Scientia 2018

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EDITOR IN CHIEF Jianna Lin

STUDENT EDITORIAL BOARD

Joshua Baker, Sean Ngo, Rachel Parker, Samuel Shenoi, Ryan Rahman, and Micheal Munson

ADVISORY BOARD

Dean Brian Raines, D.Phil.

PROFESSOR REVIEW BOARD

Tamarah Adair, Ph.D., Patrick Farmer, Ph.D., Linda Olafsen Ph.D., and Dennis Johnston, Ph.D.

PUBLISHING ADVISOR

Lauren Vorderkunz, Baylor Pre-Health Department

DESIGN TEAM

Text: Jenil Patel References Format: Micheal Munson Cover: Zach Pranske and Emily Ziperman

FUNDING AND SUPPORT

Dean Lee Nordt, Ph.D., and the Baylor University College of Arts and Sciences

PHOTOGRAPHY

Jianna Lin, Director of Photography Courtney Bishop, Photographer BURST Stock Photos

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IN THIS ISSUE

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A Letter From the Scientia Editorial Board

ORIGINAL RESEARCH

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Effects of Stress on Reaction Time, Blood Pressure and Heart Rate Adrianna Martin and Caroline Fanous

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Effects of Heat Transfer in Dust Aggregates on the Photophoretic Force Dustin Sanford, Lorin Matthews, Ph.D., and Truell Hyde, Ph.D.

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Electrical Field Influence on Growth ofBrassica rapa Andrew Ensenberger and Ali Lahiji

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Effects of 2-aminoethanesulfonic Acid on

Dugesia tigrina Leigh Hickham, Taylor Luster, Taylor Weber, and Marty Harvill, Ph.D.

The Effects of 100mM Ammonium Chloride on Tetrahymena Christian Gomez, Sydney Gauss, Anthony Hernandez, Samantha Hodges, Will Mullen, and Tamarah Adair, Ph.D.

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Actigraphy-Defined Sleep Quantity is Associated with Pre-Test Stress, Creativity, and Educational Learning Taylor Terlizzese, Chenlu Gao, and Michael K. Scullin, Ph.D.

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Effects of Differing Insulin Concentrations on Tetrahymena After 24-hour Exposure Kaitlyn Armijo, Kaitlyn Clevenger, Kimberly Imoh, Evelynne Morris, Felicia Osburn, and Hope Willenborg, andTamarah Adair, Ph.D.

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Body Mass Index, Body Image, and Total Wellness in College Women Georgie Hendrickson

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Comparing Burnout and Fitness Levels Among Medical Residents Tristin Chaudhury, Niharika Koka, and Kent Yamamoto

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URSA WINNERS ABSTRACTS 2017

ABSTRACTS

Psychology and Neuroscience

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Long Term Trends in Atmospheric Particulate Matter in Central Texas Jessica Su; Mentor: Rebecca Sheesley, Ph.D.

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Prevention of Death by Suicide in OEF/OIF Veterans Kensi Boenker

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Alveolar Epithelial Cell Ligands Targeted as Therapy for Pneumocystis Pneumonia Ariane Kubena

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Third Grade Students’ Perceptions and Attitudes Towards Science Mehul Mistry; Mentor: Marty Harvill, Ph.D.

REVIEW ARTICLES

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Review Assessing the Role of TLR4 Inhibitors in Innate Immune Response Allie Stinchcomb, Alyssa Alaniz, Liam Ferreira

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Understanding the Mechanisms of Susceptibility Genes Implicated in Autism Spectrum Disorders Kayla Murphy, Kara Barber, Keegan Bush; Mentors: Yogesh Wairkar, Ph.D., and Bob Kane, Ph.D.

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A Mouse Model of Fragile X Syndrome Exhibits Qualitative Deficits in Vocalization Behavior Kaylin Ackerman, Samantha Hodges, Suzanne Nolan, Conner Reynolds; Mentor: Joaquin Lugo, Ph.D.

Geology

Neuropharmacology of Alpha7 Nicotinic Acetylcholine Receptor in Alzheimer’s Disease Courtney Smith

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Testing Prospective Memory Theories with MouseTracker Trajectories Kiersten A. Scott; Mentor: Michael K. Scullin, Ph.D.

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A Geological Comparison of the Oil Shale, Natural Gas, and Nahcolite Resources of the Piceance Basin and their Associated Extraction Methods Hayden Ross; Mentor: Wayne Hamilton, Ph.D.

Physics

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Orbit Determination of 2004 Lexell: Applying Gauss’s Method Thayer Walmsley; Mentor: Dwight Russell, Ph.D.

Chemistry and Biochemistry

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Thiosemicarbazone Compounds as Inhibitors of Cruzain for the Potential Treatment of Chagas’ Disease Tuate Dambo, Mary Trawick, Ph.D., Samuel Odutola, Ph.D., Erica Parker, Ph.D.., and Kevin Pinney, Ph.D.

Biology

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A Cost-Effective Design For A Laparoscopic Box Trainer Austin MacDonald, Davis Payne and Marty Harvill, Ph.D.

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The Effects of Dopamine on Egg Laying Behaviors of

Caenorhabditis elegans Susana Diaz, Ialexa Plascencia, Jordan Spaude, and William Townsend; Mentor: Myeongwoo Lee, Ph.D.

STUDENT RESEARCH SPOTLIGHT

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Navin Kumar Andrew Burry Christina Gaw

For Prospective Authors

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A Letter From the Editors Jianna Lin, Joshua Baker, Micheal Munson, Jenil Patel, Sam Shenoi, Sean Ngo, Rachel Parker, Ryan Rahman

An Introduction to Scientia 2018

It is our pleasure to introduce to you Scientia 2018, Baylor’s Undergraduate Research Journal in Science and Technology. Scientia is an interdisciplinary publication that aims to increase awareness of the wide-reaching nature of undergraduate research at Baylor and to provide a unique platform for undergraduate students at Baylor University to showcase their original research. To do this, Scientia publishes a collection of selected original research articles and abstracts that span the interdisciplinary sciences chosen by Scientia’s editorial board. As advocates of maximizing our education, we believe that the promotion of research here at Baylor provides students with quintessential and formative experiences that develop valuable characteristics such as intellectual curiosity, resilience, and, simply, strong interest in the pursuit of knowledge. To us, research is a hallmark of education, because it involves applying the information learned in classes to unanswered questions in hopes of advancing our knowledge of the world around us. For these reasons, we commit ourselves to reviewing, editing, and publishing the work initiated and collaborated on by Baylor undergraduates.

Scientia is created through the student organization Baylor Undergraduate Research in Science and Technology (BURST), whose mission statement is to increase awareness of undergraduate research on the Baylor campus, provide opportunities for undergraduates to optimize their research experiences, and educate undergraduates in the proper habits and techniques of research in scientific fields. In conjunction with BURST, we hope this array of student discovery will inspire an increasing number of students to partake in the many research opportunities present at Baylor.

The process of crafting Scientia includes a methodical review of submissions and collaboration between student researchers and editors of Scientia’s Editorial Board. Student editors are closely involved in the selection of submissions for acceptance through careful review and meeting with authors to improve the professionality of the work. As undergraduate editors, we understand that undergraduate researchers are in the process of developing the skills required of professional research, and we strive to enhance these qualities in those who submit. Each author is provided with personalized guidance and an opportunity to improve their ability to compose scientific literature. Following student editor review of each accepted submission, the articles are reviewed by Scientia’s Professor Review Board, which includes Tamarah Adair, Ph.D., Patrick Farmer, Ph.D., Linda Olafsen, Ph.D., and Dennis Johnston, Ph.D. Further revisions are then made by the authors based on comments from these professors. This overall process is modulated and funded by the Deans of the College of Arts & Sciences, while the Office of Pre-Health Studies assists in the journal’s printing. We are grateful to Dean Brian Raines for his continuous support and thoughtful guidance.

Most undergraduate work in laboratories is primarily aimed to assist the research projects of graduate students and professors. Therefore, the research of most undergraduate students at Baylor is not eligible for publication in Scientia. To abridge the gap between the research we feature and the enormous amount and variety of undergraduate research that students partake in at Baylor, Scientia features students in the Student Research Spotlight section. This section of Scientia aims to highlight the work of undergraduates who assist in research at Baylor but are unable to release data or specific intellectual content they work with in hope that the research conclusions drawn from the project may be published by a professor or graduate student elsewhere.

We hope that our efforts in creating Scientia 2018 excites the scientific community at Baylor to pursue further research experiences at Baylor and beyond, and that this journal effectively conveys the magnitude of undergraduate research here at Baylor so that you will be inspired to partake in this community.

Sincerely, The Scientia Editorial Board

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Original Research

Effects of Stress on Reaction Time, Blood Pressure and Heart Rate Adrianna Martin and Caroline Fanous Baylor University, Waco, Texas

Abstract This experiment is sought to find the effect of a stressful stimulus on reaction time, heart rate and blood pressure, if any, and discover whether it correlates between gender. We hypothesized that a stressful stimulus will overall increase blood pressure and heart rate, while decreasing reaction time, and the difference will be greater observed in females. One sample of 21 students between the ages of 18-24 was selected for this experiment. Individuals were taken into a separate room in pairs of two. A baseline blood pressure and heart rate was taken previously over the weeks prior. An average of these baseline measurements is used for the first blood pressure (BT1) and heart rate (HR1) measurement. Following this, their first reaction time (RT1) was recorded using iWorx technology with LabScribe, in conjunction with a plug-in EM-220 event marker. Once this was completed a timed multi-digit multiplication math test was given. After the math test the blood pressure (BT2), heart rate (HR2) and reaction time (RT2) was once again tested. The data was analyzed using a two-sample t-test assuming equal variances. No statistical significance between males and females for the variables measured, however an inverse relationship was witnessed between blood pressure and heart rate..

Introduction

The effects of a stressful stimulus can be perceived many different ways, especially between genders. According to the American Psychological Association (2015), reaction time (RT), heart rate (HR), and blood pressure (BP) are main factors that undergo changes when there is an influence of stress. This is also referred to as the “fight or flight” mechanism or an activation in the sympathetic nervous system, which prepares the body to deal with a sudden change in its environment.

In a study conducted by Aditya Jain et al. (2015), titled “A comparative study of visual and auditory reaction times on the basis of gender and physical activity levels of first year medical students,” there was a significant difference in reaction time between males and females. Males tended to have faster reaction times than females, because although each gender has the same muscle contraction time, the motor responses for females are much weaker than in males, generating the quicker response in males (Jain et al).

Onose et al. (2017) studied the effect PTSD had between genders after a natural disaster occurs is evaluated in patients with cardiovascular complications. The pervasiveness of PTSD among females was higher than it was found to be in males. In females, PTSD proved to have more of a detrimental impact on their cardiovascular health, with more females than males dying from cardiovascular health

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problems (Onose et. al).

In 2010, a study done by Norman B. Anderson, titled “Gender and Stress in America” reported that when people were put under stressful situations, in this case lifestyle changes such as moving or job transfer, women experienced a higher level of stress than men. With 28 % of women reported to have a great deal of stress compared to 20 % of men, the researchers found that women are more likely to report physical and emotional symptoms of stress (41 percent vs. 30 percent), thus affecting their ability to focus and increasing their heart rate. In an additionl sampling year done in 2012, results were consistent. When given a stress evaluation, measured on a scale of 1 to 10, where 1 is relaxed and 10 is the highest level of stress, men had an average score of 4.8, compared to women who rated their stress levels at a 5.4.

In the study done by Shoemaker et al. (2001) “Gender affects sympathetic and hemodynamic responses to postural stress,” differences in gender in reflex responses initiated by the sympathetic nervous system were explored. Reaction time is shown to have been affected by stress more in females, because they showed a decreased neural response, indicating that their sympathetic division was not as active as in males. Their postural vasomotor responses diminished, while in males, the decline wasn’t as significant (Shoemaker et. al).

This study compared reaction times, heart rates, and blood pressures between males and females prior to and after completion of a stressful task: a written, timed math test. We expect males to have a faster reaction time than females after completion of the timed math test, as well as a lower cardiovascular response than females.

Methods and Materials

This experiment compared the difference in visual reaction time, (RT) heart rate (HR), and blood pressure (BP) for 21 undergraduate university participants (13 females, 8 males) before and after a stressful stimulus was presented.

Participants were brought into the room in groups of two to avoid being influenced by other students. Gender and ID number were recorded along with resting HR1, and BP1. For a more accurate measurement of HR1 and BP1, an median rate was calculated from several weeks of resting measurements using a digital finger pulse-oximeter and digital wrist blood pressure cuff. RT1 was measured using iWorx technology with LabScribe, along with a plug-in EM-220 event marker. Participants were instructed to press the red button with their don the EM-220 as soon as they saw the black line on the LabScribe screen. The line was randomly generated by the pressing the F1 key on the computer keyboard every three to five seconds. After RT1 is taken for both participants, they were given 2 minutes to complete a challenging multiple digit multiplication math test, and were told that whoever gets the most correct answers will be rewarded with an incentive of five dollars. HR2 and BP2 were measured immediately after the math test using a digital wrist blood pressure monitor.

RT2 was measured after the math exam using an identical method to RT1. Participants were then given a short debriefing, where they were instructed to not to disclose any information about the math test.

To analyze the data, we first divided all the data into male and female. Next we took the average for each of the before and after variables for heart rate, blood pressure and reaction time of each participant to determine patterns among each group for each of the variables. Once these averages where calculated a Two Sample t-Test was ran to determine statistical significance.

Figure 1. The before and after effects of a stressful stimuluson the systolic blood pressure (mmHg), between males and females. Based on the data collected, the systolic reading of blood pressure increased for both males and females, with a stronger increase in males, with the mean rising from 119 mmHg to 124 mmHg. The mean systolic pressure for females rose from 111 mmHg to 113 mmHg.

Figure 2. The before and after effects of a stressful stimulus on the diastolic reading of blood pressure, measured in mmHg, between male and female. There was no significant differences for diastolic blood pressure.

Results

The study was conducted on 19 participants (n=19), with 8 male participants, and 11 female participants. There was not a significant difference in the variables we measured, regarding before and after the stressful stimulus was presented to the participants (Figure 1,2).

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The statistical analysis run on the results using a Two Sample t-Test assuming equal variances showed there to be no statistical significance between males and females for the variables measured. We calculated the change for blood pressure, heart rate, and reaction time for men and women. Systolic blood pressure (t15 = 2.13144, p = 0.71), heart rate (t15 = 2.13144, p = 0.77), and reaction time (t15 = 2.13144, p = 0.94), all showing that the p-values were greater than 0.05, which conveys that there was no statiscal significance between gender.

Figure 3. Before and after effects of a stressful stimulus on reaction time, measured in seconds, between males and females. While reaction time consistently decreased for both males and females, this difference was not significant.

Figure 4. The before and after effects of a stressful stimulus on heart rate, measured in bpm, between males and females. For both males and females, heart rate declined by 5 bpm, with females generally having higher heart rates than males.

Although there were signs of the blood pressure increasing, heart rate decreasing, and reaction time decreasing after the math test was administered, there was not a notable difference between males and females for each of these variables.

Systolic blood pressure increased after the math exam for both males and females (Figure 1). Diastolic blood pressure remained relatively constant after the math exam for both males and females (Figure 2). Reaction time decreased after the math exam for both males and females (Figure 3). Heart rate declined by 5 bpm after the math exam for both males and females (Figure 4).

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Discussion

The results of the study were inconclusive and did not support our hypothesis. The results of this study showed an overall increase in blood pressure, and decreases in heart rate and reaction time after participants completed a stressful stimulus in the form of a math test. While males exhibited a stronger increase in blood pressure in response to the administration of the math test, other variables did not differ between males and females, as they were fairly uniform in their change among males and females.

Blood pressure increased after the stressful stimulus was presented. On average, systolic blood pressure increased in more in males, from 119 mmHg to 124 mmHg, while for females it rose from 111 mmHg to 113 mmHg. These results are consistent with previous studies. Through the research Reckelhoff (2001) conducted, blood pressure shows to be higher in men than in women around the same age range. However, after menopause women tend to have higher blood pressure than men, which could be due to the hormonal changes taking place at this time. The age range of the participants in this study was 19-27 years old, so menopause does not need to be taken into consideration.

Reckelhoff also concluded that androgens have an impact on blood pressure by increasing it through the renin-angiotensin system. An inverse relationship between blood pressure and heart rate was something also that was witnessed.

This shows the cardiovascular system adjusting to maintain homeostasis.

Our original hypothesis stated that women would have a greater effect from the stressful stimulus than men.

Besides males having a larger increase in systolic blood pressure, it overall was not significant, and thus, leading to our hypothesis not being supported. The lack of significant findings may be attributed to experimental design.

Subjects self assessed resting heart rate and blood pressure, using a variety of measurement methods. Some individuals used an auscultatory method, using a stethoscope and a sphygmomanometer, to measure their blood pressure, while others used the oscillometric method with an electronic blood pressure monitor. Even though both methods are prone to error, the people who used the auscultatory method probably had a less accurate measurement because this tool requires extensive experience in proper use. The

inaccuracy in baseline measurements may have limited our ability to detect a change in blood pressure after the exam.

The math test selected as a stressful stimulus may have been too difficult. This caused a few of the participants to give up as soon as looking at the paper. Giving up without making an attempt at the exam may have reduced the stress response in those subjects, as there was no external consequences for not completeing the math problems. Lastly a predominant source of error stemmed from the limited sample we had to run the experiment on. If we sampled more individuals, particularly individuals chosen from different populations and demographics, our results may have been different.

Additional research could test a larger group of subjects. Using consistent heart monitoring equipment with all subjects, particularly equipment less subject to user error, may yield more precise results. In addition, giving a more doable math test would beneficial in a future study. A test that didn’t require multiplication of decimals would be more practical to ask of the participants in otder to elicit greater responses. Instead of providing an incentive for doing well on the exam with monopoly money, we could try to provide real money for scoring the highest on the test to see if students would be more willing to do well on the exam.

The data collected from this experiment has external importance. For example, these results may be important to individuals who work in stressful employment where fast reaction times are critical, such as law enforcement. These results are useful in understanding the way individuals perform on a particular exam as well as how fast the complete the exam. They may indicate the stress response of students taking exams, particularly students who take more than one exam in a day. In addition, it can be related to how medical professionals assess a person’s health, both on the physiological level and psychological level, if the sickness is stemming from a stressful situation. The study is relevant to how clinicians evaluate health from a cardiovascular perspective, especially in regards to the blood pressure and heart rate variables that were measured, since these measurements are visually taken by a nurse or medical assistant prior to seeing a physician.

References [1] American Psychological Association Stress and Gender.

2011.

[2] Jain, A.; Bansal, R.; Kumar, A.; Singh, K. D. A comparative study of visual and auditory reaction times on the basis of gender and physical activity levels of medical first year students. International Journal of Applied and Basic Medical Research. 2015, 5(2), 124.

[3] Onose, T.; Sakata, Y., Nochioka; K.; Miura, M.; etc. Sex differences in post-traumatic stress disorder in cardiovascular patients after the Great East Japan Earthquake: a report from the CHART-2 Study. European Heart Journal-Quality of Care and Clinical Outcomes 2017, 3(3), 224-233.

[4] Shoemaker, J. K.; Hogeman, C. S.; Khan, M.; etc. Gender affects sympathetic and hemodynamic response to postural

stress. American Journal of Physiology-Heart and Circulatory Physiology 2001, 281(5), H2028-H2035.

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Original Research

Effects of Heat Transfer in Dust Aggregates on the Photophoretic Force Dustin Sanford, Lorin Matthews, Ph.D., and Truell Hyde, Ph.D. CASPER, Baylor University, Waco, Texas Abstract A dust grain suspended in a low density gaseous environment and illuminated by a radia-tion source, such as a star or laser light, develops a temperature gradient across its surface. As gas molecules collide with the grain and equilibrate with the surface temperature of the dust, the mole-cules on the hot side transfer more momentum to the grain due to their greater rebound velocities than molecules on the cold side. This difference in momentum transfer results in the photophoretic force, which is (usually) directed away from the illumination source. Photophoresis may have a large impact on protoplanetary disks by sorting dust by size, material, or geometry and in the pro-cess, create rings of high and low dust densities.

Photophoresis may also increase relative veloci-ties between dust grains of different properties, which could increase the rate of aggregation and accelerate planet growth. However, experiments have shown that some illuminated dust grains move on helical paths, or with a velocity at an angle to the direction of illumination. The magnitude and direction of the photophoretic force is dependent on the magnitude and orientation of the tem-perature gradient on dust grains. To more fully understand the effects of photophoresis in pro-toplanetary disks, this project develops a numerical model for the heat flow in aggregate dust grains in order to determine the photophoretic force on aggregate grains. The distribution of the direction of the drift velocity with respect to the illumination direction agrees with previous experimental studies.

Introduction The behavior of dust aggregates under the influence of the photophoretic force may play a role in the formation of planetary embryos in protoplanetary disks. Pebble accretion theories have arisen in response to the bouncing and fragmentation barriers for collisional aggregate growth [1]–[3].

Photophoresis has been proposed as an aiding mechanism in the creation of high density dust regions, which are required by many pebble accretion theories [4]. Also, high planetary embryo surface luminosities caused by rapid embryo formation can generate temperature gradients in the surrounding gas, which subjects dust to the photophoretic force [3], [5].

Photophoresis occurs when a dust grain that is suspended in a low density gaseous environment develops a temperature gradient across its surface due to an anisotropic radiation field. When a gas molecule collides with the dust grain, its temperature equilibrates with the local dust grain surface temperature. The net momentum transferred to the grain generally causes the grain to accelerate away from the illumination source [6]. However, experiments have found that the photophoretic force can accelerate grains in any direction relative to the illumination direction, particularly in the case of aggregate grains [7], [8]. The magnitude

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and direction of the photophoretic force are dependent upon the magnitude and direction of the temperature gradient across the dust grain [7]. Negative photophoresis occurs when the orientation of the temperature gradient causes the dust grain to be accelerated towards the illumination source. A numerical model was developed to investigate the photophoretic force acting on irregular Âľm-sized aggregates built from spherical monomers [9].

While the model reproduced the general trends for the distributions of the magnitude and velocity of the photophoretic drift observed in the paired experimental study [9], a heuristic algorithm was used to calculate the temperature gradient for the dust aggregates. Furthermore, the model for the temperature gradient did not predict negative photophoresis, as observed in experiment [7], [10].

This study builds on the numerical model for photophoresis developed in [9] by evaluating the effects of heat transfer processes in irregular aggregate grains.

Numerical Model

Aggregates are built from collections of spherical monomers. Each monomer is divided into discrete volumes, the top face of which are defined by twenty patches spaced evenly over the surface, and an additional equivalent volume at the grain’s center. The temperature of each volume is characterized by the temperature at the center of the volume, which is determined by summing all of the heat transfer processes to that volume: heat transfer to the surface by illumination, black body radiation, and collisions with gas molecules, as well as conduction between adjacent volumes.

Given an illumination source acting along a single direction, the magnitude of the radiation energy absorbed by a patch on a monomer’s surface during a time Δt is given by

where Ii is the illumination intensity with its direction given by the illumination direction, ni is the unit vector normal to the surface patch, ∆Ω is the solid angle subtended by the patch on the surface of the monomer, and LOS is a Boolean value, set to zero if the line of sight (LOS) along the illumination direction is blocked by another monomer in the aggregate, and one if the LOS is open.

The heat conduction within a monomer during a time Δt is calculated from the sum of the conduction between all adjacent volumes, given by

where A is the area of the contact surface between the volumes, ΔT is the temperature difference between the two volumes, k is the thermal conductivity, and l is the distance between their respective center of mass.

The attractive forces that hold monomers in an aggregate together, such as the Van Der Waals force, cause touching monomers to deform at their point of contact.

This deformation creates a circular contact area between touching monomers (Figure 1). Conduction between monomers occurs through these circular contact areas, which can vary in size. This conduction occurs between the two closest volumes on touching monomers and follows equation (2), except A is the contact area between monomers and l is half the distance between the centers of the touching monomers.

Figure 1: The circular contact area between two monomers created by the forces holding the monmers together, such as the Van Der Waals force.

Aggregates are treated as black bodies where each patch can radiate to free space as well as to other monomers within the aggregate. One thousand straight line paths, or lines of sight (LOS), are drawn from each patch and then checked to determine if each LOS is blocked or open. Open LOS radiate to free space and the heat transfer is calculated by

where σ is the Stefan-Boltzmann constant, Tp is the temperature of the volume, Ts is the temperature of space, ΩLOS is the solid angle of a single LOS, and N is the number of free LOS. Blocked LOS radiate to other patches, where the heat transfer between two patches is calculated by

where Tb is the temperature of the blocking patch, and n is the number of LOS from the first patch blocked by the second patch.

When a gas molecule collides with the aggregate, it equilibrates with the local surface temperature before being ejected. The magnitude of the heat exchange due to all gas molecules which strike a patch is given by

where Igas is the gas flux and ΔT is the change in temperature of the gas molecule from the ambient gas temperature to the local aggregate surface temperature.

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rection than aggregates with large contact areas (Figure 4).

Both populations produced negative photophoresis, and the distribution of the drift velocity direction is representative of the observations in [7].

Figure 2: (a) Photophoretic force vs. number of monomers, normalized to the force on a single monomer, f = 1x10^16 N. (b) Drift velocity vs. number of monomers.

Figure 4: Distribution of drift velocity with respect to the illumination direction for dust aggregates calculated with small (a) and large (b) monomer contact areas. Zero degrees represent a drift velocity directed away from the radiation source.

Figure 3: Temperature gradient on a dust aggregate composed of 71 monomers calculated with small contact areas (a) and with large contact areas (b) Results Preliminary data are shown for a population of silicate aggregates generated using a combination of particle-cluster and cluster-cluster aggregation as in [9]. Each aggregate was simulated twice with different values for the contact area between monomers, once with contact areas calculated theoretically as in [11] yielding an area of 0.015 Îźm2, and then with contact areas based on experimental images from [7] yielding an area of 1.815 Îźm2. Conditions typical of a protoplanetary disk were assumed where the gas temperature was 300 K, the illumination intensity was 10 kW/m2, and the average gas particle mass was 2.3m_p, with m_p as the proton mass [9].

Large contact areas yielded linear temperature gradients, while small contact areas caused non-linear temperature gradients with hot spots often located in the center of the aggregate (Figure 3). As a result, aggregates with small contact areas had a larger variance in drift velocity di-

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Preliminary results show that the small contact areas produce a larger variance in the magnitude of the photophoretic force and drift velocity than the large contact areas. However, the average drift velocity is the same for both contact areas and is not correlated with the number of monomers in an aggregate (Figure 2). Future work is will examine larger aggregates.

References [1] J. Drazkowska, Y. Alibert, and B. Moore, “Close-in planetesimal formation by pile-up of drifting pebbles,” ArXiv160705734 Astro-Ph, Jul. 2016.

[2] M. Lambrechts and A. Johansen, “Rapid growth of gas-giant cores by pebble ac-cretion,” Astron. Astrophys., vol. 544, p. A32, Aug. 2012.

[3] J. E. Owen and J. A. Kollmeier, “Dust traps as planetary birthsites: basics and vortex formation,” ArXiv160708250 As-tro-Ph, Jul. 2016.

[4] N. Cuello, J.-F. Gonzalez, and F. C. Pignatale, “Effects of photophoresis on the dust distribution in a 3D protoplane-tary disc,” Mon. Not. R. Astron. Soc., vol. 458, no. 2, pp. 2140–2149, May 2016.

[5] C. Loesche, G. Wurm, T. Kelling, J. Teiser, and D. S. Ebel, “The motion of chondrules and other particles in a pro-toplanetary disc with temperature fluctua-tions,” Mon. Not. R. Astron. Soc., vol. 463, no. 4, pp. 4167–4174, Dec. 2016.

[6] S. Tehranian, F. Giovane, J. Blum, Y.-L. Xu, and B. Å. S. Gustafson, “Photopho-resis of micrometer-sized particles in the free-molecular regime,” Int. J. Heat Mass Transf., vol. 44, no. 9, pp. 1649–1657, May 2001.

[7] M. Küpper, C. de Beule, G. Wurm, L. S. Matthews, J. B. Kimery, and T. W. Hyde, “Photophoresis on polydisperse basalt microparticles under microgravity,” J. Aerosol Sci., vol. 76, pp. 126–137, Oct. 2014.

[8] G. Wurm and O. Krauss, “Experiments on negative photophoresis and applica-tion to the atmosphere,” Atmos.

Environ., vol. 42, no. 11, pp. 2682–2690, Apr. 2008.

[9] L. S. Matthews, J. B. Kimery, G. Wurm, C. de Beule, M. Kuepper, and T. W. Hyde, “Photophoretic force on aggregate grains,” Mon. Not. R. Astron. Soc., vol. 455, no. 3, pp.

2582–2591, Jan. 2016.

[10] I. von Borstel and J. Blum, “Photophore-sis of dust aggregates in protoplanetary disks.” [Online]. Available: http:// www.aanda.org/articles/aa/pdf/2012/12/aa19622-12.pdf.

[Accessed: 01-Nov-2016].

[11] C. Dominik and A. G. G. M. Tielens, “The Physics of Dust Coagulation and the Structure of Dust Aggregates in Space,” Astrophys. J., vol. 480, no. 2, p. 647, 1997.

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Original Research

Electrical Field Influence on Growth of

Brassica rapa

Andrew Ensenberger and Ali Lahiji Baylor University, Waco, Texas Abstract Scientists have experimented with electric fields and their possible impact on plants for generations. In such studies, plants were usually exposed to impractical strengths of voltage in a controlled laboratory. This experiment drew from previous ones, but was unique in that it sought to find a correlation between plant growth and plant exposure to a more naturally occurring constant electric field. Separate groups of plants were grown in the presence of continuous electric fields of varying intensities. Both dry mass and height were used as a measure of growth. The resulting data suggests with statistical certainty that some voltages promoted plant growth, while others greatly impeded growth. The general trend depicted that relatively lower levels of voltage better-promoted plant growth, opposing the initial hypothesis that higher voltage exposure results in more favorable effects. After a certain threshold, it appears electric fields are, in fact, detrimental - likely due to the continuous nature of the electric field. Due to the energy efficiency and cost-effective nature of the project’s design, these findings have significant implications. They can prove useful in third world countries, space travel, and in harsh climates where conservation of power and increased food yield is essential.

Introduction Humanity has consistently redefined the boundaries of what is possible. With the dawn of power lines and other methods of transportable energy, societal advancement has increased exponentially. One of recent history’s most important advances was the discovery and utilization of electricity. Today, electricity is universal. Most people are familiar with the basic concepts of power. Still, some are skeptical about the safety issues that come with utilizing such forces for energetic needs or scientific advancement.

In an article published by scientists Swanson and Jeffers, the authors regard that these suspicions have been around for almost twenty years, that power sources may have a negative impact on our well-being as a species.8 One of the goals of this experiment is to determine if electric fields are detrimental to the organisms under direct exposure. By exposing plants to electric fields of varying intensities, a more confident prediction of the effects of electrical fields on other organisms, namely humans, will arise. Previous similar experiments have shown a positive effect resulting from the presence of the electrical phenomenon during plant germination. In one study, seeds were subjected with up to 800 kV/m for 30 seconds before they were allowed to germinate.

Stanko observed that substances containing nitrogen moved into plant roots and shoots much faster. He also noticed stockpiled sugars, nucleic acids, and amino acids in the stimulated seedlings.7 Stanko’s findings provide insight into

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the reasons an electric field could enhance plant growth, but his design is not very practical. Such extreme circumstances are not regularly found in nature nor are they very energy efficient. A more pertinent experiment was carried out by Lemström in the 1800s. Lemström recorded his travels to the Earth’s Arctic Pole and observed naturally occurring anomalies in fir tree growth, which he contributed to the greater electric fields found in that area.4 Lemström’s work inspired this present-day experiment, and shifted the aim towards quantifying the effects of more economically feasible electric fields. The Stanko Experiment yielded positive growth for short bursts of extremely high voltage; thus, this study’s original hypothesis was that the stronger the electric field, the greater the growth would be.3 Another difference this experiment considers is comparing both mass and height to define “growth,” whereas others observed a single factor. This more holistic comparison between the two types of measurement should give more precise and usable results. The plant of choice was the Brassica rapa, or “Wisconsin Fast Plant.” This plant species was chosen due to the short germination length, which would allow for two trials to be completed within the short time frame allocated.

Methods and Materials

This experiment aimed to quantify the effects of constant and long-term electric field exposure on the height

and dry mass of Brassica rapa. In order to do so, two phases were set up. In each phase of the experiment, low voltage, high voltage, and control groups were set up. A control was grown for each trial so that each charged group could be compared to its respective control, grown under the same circumstances. 90 seeds were distributed among the three groups, 30 in each group to satisfy the conditions of running statistical significance tests. The seeds were planted 2 cm deep and watered daily with deionized water. Once the plants had sprouted, average plant height was recorded daily for the first phase. After ten days of growth under a constant electric field, the plants were removed, any attached soil was rinsed off, and the plants were left under a light bulb to dry out. After three days, the dry masses of each group of plants was weighed and recorded in grams.

To create each setup, rectangular plates were cut from aluminum metal sheets to fit the dimensions of the containers housing the plants. The 30 Brassica rapa plants in each group were placed inside two small plastic bins labeled “Tub Front” and “Tub Back” with respect to their position within the apparatus. This minimized the distance between the two aluminum plates, which in turn minimized interference. The distance between each pair of charged plates was set to 0.305 meters; one plate was connected to the negative terminal of a DC battery, and the other plate was attached to the positive terminal. Insulated copper wires were used to prevent current leakage. The dimensions of the aluminum plates were 31.5 by 18 inches. Wooden supports of 12 inches connected the four corners of the oppositely charged plates.

Illustrations 1-4 below visualize these aspects. An ohmmeter was used to measure the voltages of the aluminum plates daily, to ensure that the voltages matched the values of the experiment, by attaching the electrodes to the positive and negatively charged plates. Additionally, cardboard cutouts roughly the same dimensions as the aluminum plates were placed between setups to isolate them and reduce interference with one another.

The isolated laboratory housing was held at a constant 22°C, within the optimal temperature growth zone for the Brassica rapa (between 18°C and 26°C), as per the instructions included with the seedlings. A light was hung approximately two feet above each group and was kept on for 24 hours each day, accelerating the growing process by allowing the plants to grow overnight. The watering process remained consistent between the bins, and the volume of water given to the plants varied per day depending on soil dampness, with the average amount being 557 mL for Phase One and 256 mL for Phase Two. Tempreature, atmospheric pressure, light, water, and method of measurement were carefully monitored and kept constant between the three bins of each phase.

Illustration 1: Side view of a computer generation of the aluminum plate setup. Included are dimensions of aluminum plates and measurements for placing holes for screws to set into wooden supports. 1/8” hole is for attaching wire from external battery to give electrical charge to the plate.

Illustration 2: Actual setup used for experiment. Assembly modeled from Illustrations 2 and 3 listed above. Cardboard cutouts separate setups from one another.

In Phase One, the three setups were charged with voltages of 0, 24, and 100 V to gain a baseline of data and adjust accordingly for Phase Two. One battery was configured to apply 24 V, and the other 100 V, with the final bin serving as the control. These voltages correspond to 0, 78.74, and 328.08 V/m respectively. During this initial phase, a ruler was used to measure average plant height in each bin to the nearest centimeter. At the conclusion of this trial, the plants were uprooted, dried out, and the mass was calculated and recorded.

Upon reviewing the results from Phase One, it was decided that the voltages of Phase Two be set to 0, 6, and 12 V, which correspond to 0, 19.69, and 39.37 V/m respectively. In addition, the method of watering the plants was changed by gently trickling the water onto the plants to remove the chance of displacing the seeds.

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The amount of water given was also edited to make sure that the plants were not being over watered.

Throughout the second phase, instead of roughly measuring plant height averages per bin with a ruler as in Phase One, a caliper paired with a ruler was used to record the height for each of the plants to the nearest millimeter. This process was much more time-consuming since measurements were repeated three times to ensure accuracy. As with the previous phase, a dry mass test was conducted at the end.

During Phase Two, the 6 V (low voltage) containers were not usable due to an experimenter who failed to properly water these plants, thereby decreasing the average water amount for Phase Two. In addition, a single seed, position A1, within the control and 12 V back bins during Phase Two, did not sprout and was gauged accordingly in the results.

Results

The presence of voltage had a statistically significant impact on the height of Brassica rapa, though the initial difference did not support the hypothesis. As mentioned previously, to help keep these observations accurate, each trial was compared to its respective control group. The data shows that, on average, plants under electrical field influence had a higher dry mass with respect to their control group.

Phase One’s fundamental purpose was to discover an existing trend, if any. It also provided a smaller confidence interval in which we could find a positive effect. At the conclusion of Phase One, average height and dry mass of each setup were recorded. Figures 1 and 2 below illustrate these aforementioned findings.

Figure 2: Comparison of the dry mass of the three setups at the conclusion of Phase 1

An identical design was employed in Phase Two as was used in Phase One. Only the strengths of the voltages were altered via the battery. Figure 3 below depicts the results of this second trial, as well as an ANOVA Test of significance, and Figure 4 shows the results of the dry mass test.

Figure 3: This graph plots Average Plant Height (cm) vs.

Time (Days) for Phase 2.

Figure 1: Average Plant Height (cm) vs. Time (Days), pertains to Phase 1. Blue line represents control (0V); yellow line represents 24 V; green line represents 100V.

For Phase One, as depicted in Figure 2, the final height of the 24 V container plants was 4.32 cm, and the dry mass was 0.181 g. The control group, on the other hand, had a final height of 4.47 cm and a dry mass of 0.148 g at the conclusion of the experiment.

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Figure 4: This chart compares the dry mass of the experimental and control groups at the conclusion of Phase 2.

At the end of Phase Two, the average height of plants exposed to 12 V was 3.791 cm, and the average height of the control group was 3.483 cm. Average daily growth was also higher for the 12 V plants, measuring at 0.502 cm/day, whereas the 0 V plants lagged behind with an average growth rate of 0.443 cm/day. After meticulously measuring and recording the individual heights of 90 plants to the nearest millimeter, a statistical significance test was conducted between the average heights of the 12 V group and its 0 V control. To perform this test for significance, an ANOVA Single Factor test was conducted. Measuring the heights of all 12 V plants over the full duration of Phase Two, compared to the height of the Phase Two control, formed the data points to be run by the ANOVA test. With a P-value of 0.080129 and an Alpha of 0.1, the conclusion can be drawn with a 90% accuracy that there was a significant statistical difference of height between the average of the two groups throughout Phase Two.

Furthermore, the significance of the last day of Phase Two using a One-Tailed Hypothesis Test was tested.

This test was selected due to the interest of observing an increase in growth at the positive end of a standard normal distribution bell curve. All previous articles cited indicated a positive growth with an application of voltage. Therefore, it was unnecessary to test the negative end of the bell curve.

As previously discovered, voltages from Phase One demonstrated more and more detrimental effects the higher the exposed voltage. Because of this, the focus should be put on one direction of the bell curve over the other, as a OneTailed Hypothesis Test evaluates.

The difference between each experimental 12 V plant and its respective control was calculated to test for significance. This method was used because the position of the plant in the container could affect plant growth. The mean difference between the experimental plants and their control was +0.305 cm with a standard deviation of 0.913 cm as shown beneath in Exhibit 1.

Based on the 95% confidence level of a One-Tailed Hypothesis Test, a 1.64 threshold was applied to the standard deviation of the mean to calculate the significance of hypothesis test and find value height necessary for significance of the experimental group on Day Nine.

Because the mean difference of +0.305 cm is larger than the calculated threshold of 0.278 cm, it is therefore plausible to reject the null hypothesis that there is no difference in the growth rates between experimental plants and its respective control.

As the 12 V surpassed this threshold value of an average height of 3.78 cm on Day Nine, it can be concluded that Day Nine’s data in Phase Two was significant. As this was the last day of the experiment, and the final culmination of all trials in this experiment leading up to it, Day Nine’s significance is very important and helps show overall

impact of the investigation.

Not only average plant height, but also the dry mass of the 12 V setup aligned with the revised hypothesis.

In Phase Two, the experimental plants had increased mass compared to their control. The 12 V containers had a dry mass of 0.146 g while the control had a dry mass of 0.103 g. With the 12 V containers having masses of 142% that of their control, data supports that electrical fields can assist plant physiology not only in height but also in density. This evidence can be extrapolated to many potential benefits in numerous areas of application.

Discussion

Initially, previous research seemed to conflict with the results found in trial one. In Ellis’ experiment, plants were placed under wire-mesh hanging seven feet above that was charged with 40-80 kV (up to 37,505 V/m) for 3-hour sessions and displayed significant positive results.2 Stanko also used high voltage and achieved positive results.7 Despite applying a voltage 400 times smaller than that used in Ellis’ works, detrimental effects on plant growth were observed in Phase One of this experiment, especially in the 100 V group. The original hypothesis was quickly disproven as it became apparent that the most powerful electric field, 100 V or about 328.08 V/m, was stunting plant height. A possible explanation for this was the constant exposure of the plants in this experiment to current, divergent from the comparatively short bursts Stanko employed.7 Over time, even a weak electric field could perhaps be more influential than a powerful yet brief one. This line of reasoning agrees with Lemström, who noticed positive growth in naturally occurring electrical fields.4 Noting this, the experiment was adjusted accordingly, and Phase Two began. The purpose of Phase Two was to test the effects of weaker electric fields on plant growth and determine whether a significant, positive, difference would arise. The hypothesis was revised so that a voltage between 0 and 24 V would show positive growth under this sustained exposure.

To help explain this data, answers were drawn from Xiao’s work, a scientist who studied how much electrical fields promote atmospheric carbon dioxide absorption in plants. The increased intake of atmospheric CO2, he noticed, led to more dry mass.9 Furthermore, fast-growing plants are observed to take up nutrients more quickly, with their net nitrate uptake being four to six times larger in fast-growing species. 6 The 12 V containers may have caused a faster rate of ion intake, as one of the most common, naturally existing ions in soil is nitrate.

The effects observed in this experiment have significant implications that can be applied to help major industries and assist in making critical advancements in society. Using electricity and wire, farming in disadvantaged areas of the world can potentially benefit from this experiment. Area

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can easily be changed as dimensions in the fields can be kept proportional to voltage set. This allows a farm to have the ability to make custom electric fields so long as they can supply the constant 12 V power necessary. This caveat becomes a problem when applying previous experiments, as such vast quantities of electricity required for any potential benefit is outside the realm of possibility for some farmers.

A practical solution to help pay for the cost of large-scale farming is solar panels that can be applied to the energy sources. This experiment was able to decrease the vast amount of voltage needed compared to other experiments, while still maintaining a significant growth in plant groups impacted by the electrical field. This is an important observation due to the realization that even though this experiment came to similar conclusions to other experiments, what separates other experiments from this study is the difference of voltage versus exposure. The challenge will be finding an efficient method to supply such a large area with a consistent electrical field without creating a biohazard in the process.

In addition, the findings from this experiment can be used in the future for space travel. Development of sustainable hydroponic farming in NASA and other space exploration entities may be able to mimic the effects on crops using a similar setup to this experiment. As of now, space expeditions are short in length and individuals do not need long-term food supply according to NASA. To understand how this experiment can help, defining hydroponics shows where a niche could exist for electric fields. Space travel uses hydroponics, which is the method of raising plants in nutrient solutions rather than normal soil. The soil is removed due to weight limitations, and to avoid particles floating in zero gravity.3 Easy modifications can be made to incorporate an electrical field. The lack of soil would create more exposure to an electrical field. While data can be extrapolated to assume an even stronger influence from the electrical field and possibly a positive result, more testing would be required to confirm this.

Concluding this experiment, there are a few factors that could have helped improve the study. To refine the results and receive additional data, allowing a larger window for time to allow the plants to go through full life cycles would have proven beneficial. The reason this experiment was carried out over the course of ten days was due to previous similar experiments that determined that most of the growth between electrified plants happens very early after germination.2 More so, a larger sample size would solidify any findings observed in this experiment. Additional space and funding towards supplying plant seeds would be necessary. Additionally, more sensitive and accurate tools for measurements could have given more concise results. High precision is important because this experiment dealt with plants growing on a scale of centimeters daily.

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References [1] Church, Christopher et al. “Integrated Electrical Con centration and Lysis of Cells in a Microfluidic Chip.” Biomicrofluidics 4.4 (2010): 044101. PMC. Accessed 24 Apr. 2017.

[2] Ellis, H. W., and E. R. Turner. “The Effect of Electricity on Plant Growth.” Science Progress (1933- ), vol. 65, no.

260, 1978, pp. 395-407. Accessed 5 Apr. 2017.

[3] Green, Michael. “Pure Innovation.” https://www.nasa. gov/offices/oct/home/tech_life_asa_analytics.html (accessed Apr 30, 2017).

[4] Lemström, Selim. “Electricity in Agriculture and Horticulture.” London: “The Electrician” Printing & Publishing Company, ltd., 1904. Accessed 15 Apr. 2017.

[5] McNeil, Paul L., Miyake, Katsuya, and Vogel, Steven.

“The Endomembrane Requirement for Cell Surface Repair.” Proceedings of the National Academy of Sciences of the United States of America (2003) 100 (8) 4592-4597; published ahead of print April 2, 2003, doi:10.1073/ pnas.0736739100. Accessed 1 May 2017.

[6] Scheurwater, I., et al. “Why do Fast- and Slow-Growing Grass Species Differ so Little in their Rate of Root Respiration, Considering the Large Differences in Rate of Growth and Ion Uptake?” Plant, Cell and Environment, vol. 21, no.

10, 1998, pp. 995-1005. Accessed 21 Dec. 2017.

[7] Stanko, S.A., and Koshevnikova N.F. “Physiologico-Biochemical Changes in Wheat Plants Before and After Pre-Sowing Treatment of Seeds with an Electric Current.” (in Russian), Sel’Sko-Khozyaistvennaya 7: 624-626. Accessed 11 Apr. 2017.

[8] Swanson, John, and Jeffers, David. “Possible Mechanisms by which Electric Fields from Power Lines Might Affect Airborne Particles Harmful to Health.” Journal of Radiological Protection, vol. 19, no. 3, 1999, pp. 213-229, doi:10.1088/0952-4746/19/3/202. Accessed 21 Apr. 2017.

[9] Xiao, L.; Liu, G.-B.; Xue, S. “Elevated CO2 Concentration and Drought Stress Exert Opposite Effects on Plant Biomass, Nitrogen, and Phosphorus Allocation in Bothriochloa ischaemum.” Journal of Plant Growth Regulation 2016, 35 (4), 1088–1097 DOI: 10.1007/s00344-016-9606-1.

Accessed 24 Apr. 2017.

Acknowledgements

Wickramasinghe Ariyasinghe, Ph.D., instrumental in forming, revising, and supplying this experiment as well as explaining relevant application of physics Richard Bill, Organization and Interpretation of Data Chara Blackwell, Organization and Interpretation of Data Marty Harvill, Ph.D., Senior Lecturer Amber Ludtke, Student Research Advisor Chris Nguyen, Experimenter Joseph White, Ph.D., Biological Application Consultant

Original Research

Effects of 2-aminoethanesulfonic Acid on Dugesia tigrina Leigh Hickham, Taylor Luster, Taylor Weber, Marty Harvill, Ph.D. Department of Biology, Baylor University, Waco, Texas Abstract The purpose of this experiment was to measure the effects of the controversial sulfur-containing amino acid, taurine, on memory retention in Dugesia tigrina, a regenerative species of planaria. For decades, skeptics vehemently opposed the addition of taurine into baby formula and energy drinks¹. It is hypothesized that taurine-concentrated solutions will impair the retention of memory in the regenerative planaria, concluding that the additive in baby formula could adversely affect infants. The experimental specimens, regenerative flatworms, are an underestimated tool used to provide a platform to delve into the world of memory. They serve as model organisms for several reasons, the most significant being that they possess a central nervous system, “They are the first to have a true synaptic nervous system, definite encephalization, and bilateral symmetry”². Classical conditioning using light association and electric shock was used to train forty-eight Dugesia tigrina in spring water, and their baseline response times to the light stimulant were recorded³. Each planarian received twenty-five rounds of electroshock therapy once a day for a duration of seventeen days. The trained planaria were then placed in a gradient of taurine-concentrated solutions and their response times were logged again after seven days. The average baseline response time of planaria in spring water was 0.522 seconds and the planaria in taurine-concentrated solutions averaged 0.50 seconds slower. This significant difference supports the hypothesis that taurine negatively affects physiological responses in Dugesia tigrina.

Introduction Taurine, 2-aminoethanesulfonic acid, is naturally produced in the body and is primarily found in “the brain, eyes, heart, and muscles”⁴. Taurine plays an important role in development of the central nervous system, brain growth, and myelination.⁵ According to a study done by the Department of Comparative Pathophysiology at the University of Tokyo, taurine is concentrated in the hippocampal region of the brain, “and modulates synaptic transmission as an inhibitory neuromodulator interacting with g-aminobutyric acid type A (GABAA) or glycine receptors”⁶. Recent studies performed on rat brain preparations have shown that the introduction of taurine into the brain resulted in consistent strengthening of synapses, “the features of this taurine-induced synaptic potentiation are similar to those of long-term potentiation (LTP), which is a typical example of synaptic plasticity, and is thought to be a basic model for learning and memory, indicating that taurine is likely to be involved in learning and memory”⁶. Given its vital role in developing memory function, it was postulated that taurine would impact the ability of planaria to retain and learn information gained through behaviorally induced stimuli. Planaria were used as test subjects due to their rudimentary central nervous system and ability to learn. These attributes provided an easily observable response to classical conditioning.

Due to its vital role in these rudimentary stages of development, taurine is a common additive to baby formula and energy drinks. In addition to its use in these substances, taurine has traditionally been used to treat various medical conditions including “heart failure, epilepsy, chemical dependencies, and hyperactivity”¹. Human adults are able to synthesize taurine using the amino acids methionine and cysteine, however, infants do not possess this ability, requiring a limited amount dietary intake, usually provided by the mother’s breast milk. This inability to synthesize the enzyme that produces taurine only lasts a short period of time, “Full-term babies only need this additional source of taurine for about two weeks, while prematurely born infants may need it for a longer period of time based on doctor’s’ recommendations”⁷. Although taurine is necessary for childhood development, it is possible to be supplemented an excess of taurine, which could potentially bring about negative consequences. In 1984, taurine was added to instant baby formulas to serve as a nutritional substitute for breast milk. However, unlike the biologically-produced taurine in breast milk, taurine in baby formula is produced synthetically through the use of sulfuric acid, which is “a toxic and carcinogenic substance”⁵. Another method to produce synthetic taurine uses aziridine. According to the Environmental Protection Agency, aziridine is listed as a hazardous air pollutant⁵.

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The harmful methods used to create synthetic taurine should alarm parents and force them to reconsider all options when choosing formula. Throughout the experiment we tested to see if an excess of taurine in body would adversely affect the response times.

Methods and Materials The experiment is designed to test the potential progression of memory in forty-eight planaria to measure the effects of taurine on the Dugesia tigrina. All forty-eight Dugesia tigrina were separated into individual petri-dishes filled with spring water at room temperature. Twenty-four petri-dishes were labeled C1-C24 and the other twenty-four petri-dishes were labeled T1-T24. After allowing three days for the Dugesia tigrina to adjust to the change in environment, the training phase began. Classical conditioning was used to train all the Dugesia tigrina to associate light with 5.1V of energy (shock); the light served as the positive stimulus and shock served as the negative stimulusÂł. All Dugesia tigrina were trained in spring water to create a consistent baseline response in all Dugesia tigrina. Each worm received twenty-five rounds of shock therapy once a day for a duration of seventeen days. The therapy was delivered in thirty-second intervals to allow a recovery time for the worms between each trial. The electroshock therapy provokes a response, measured as longitudinal contraction of the body, in the Dugesia tigrina. The following sequence of pictures illustrates the bodily response during training:

Through repetitive shock therapy the Dugesia tigrina developed the basic signs of learning. The shocking mechanism consisted of a 5.1V shock originating from a wall-plug, phone charger, electrical tape, and two needles adhered to the wires from the charger. One of the needles served as the cathode and the other s the anode. The organism was placed in between these two needle points and a shock reverberated through its body when the needles were placed in the water, promoting a response.

After measuring the baseline response, the memory retention phase began. The forty-eight trained Dugesia tigrina were split into four groups: a control group of regular spring water and a gradient of three different concentrations of taurine. C1-C12 was the control group in spring water, C13-C24 was concentrated with 0.045g/1L(~6 mg) of taurine, T1-T12 was concentrated with 0.126g/1L(~12 mg), and T13-T24 was concentrated with 0.0813g/1L(~20 mg).

After seven days, the new response times were recorded and compared to the baseline responses.

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The first day the responses were recorded, the times had almost doubled from the baseline, seven days before.

When the responses were taken on the fourth day, the worms took even longer to respond. This shows that there is a direct correlation between the higher concentrations of taurine and slower response times.

Results The original hypothesis was supported based on the statistical ANOVA (Analysis of Variance) single-factor test- there was significant difference in reaction times between the control group and all of the experimental groups. Therefore, the null hypothesis was rejected at an alpha level of 0.05.

This statistical analysis provides 95% confidence that the data found demonstrates a significant difference between the various experimental groups involving three different concentrations of taurine.

Table 1: The table shows the similarity of the averages on

day 1 and additionally shows the effect of the three concentrations of taurine on the averages after two more days.

Graph 1: The line graph to the left offers a visual correlation of the statistical significance between the three concentrations of taurine and the baseline response time of the planaria.

Graph 2: The bar graphs offers a different representation of the statistical difference between the three levels of taurine and the baseline response time of the planaria.

Discussion and Conclusion It is interesting to note a direct correlation between the increased response times and the increased taurine concentrations in the spring water (see Figure 1). Based on the response time disparity between the experimental groups, there was a statistically significant variance between the planaria, as seen in Figure 1. The average baseline time for the control group was 0.522 seconds, and after the seventh day waiting period the average response time had doubled to 1.229 seconds. This shows that a greater amount of taurine present, resulted in slower response times. This experiment thoroughly supports the hypothesis, providing evidence that taurine negatively influences the organism’s ability to respond to stimuli.

The forty-eight organisms in this study were of different sizes, which may have led to differences in training times, as some took six days to learn and some took the full seventeen days. It was observed that the larger organisms had a more dramatic response and learned more efficiently.

Another compelling observation was that, when the light was flashed on the organisms, the planarian would attempt to hide in the black numbering on the petri dish. It was if they were trying to find shelter from the light. Furthermore, on the third day of data collection, four organisms in the 12mg solution and three organisms in the 20mg solution were found dead. Although the cause of death is uncertain, it is interesting to note that only those submerged in taurine died. After only ten days, five out of the twelve organisms in 20 mg of taurine died, four out of twelve organisms in 12mg had died, and two out of twelve organisms in 6 mg of taurine had died. Although these deaths cannot add to the hypothesis be cause their deaths do not correlate with memory, they do provide serious physiological implications.

Given taurine’s relationship to brain development, findings are counter to the generally accepted belief that taurine enhances memory⁶. The planaria are also not able to be directly compared to any person ingesting taurine as they are small flatworms and are not as highly advanced as humans.

If, in fact, the planarian central nervous system can be

correlated to the human central nervous system, then future experiments could be conducted to further understand the basis of learning and memory. This research was conducted to identify a potential problem with a supplement, not directly make connections to the human population.

Potential error was accounted for when taking the measurements: the fastest the researchers could stop the timing device was 0.20 seconds and therefore a response faster than 0.20 seconds was considered “immediate.” Another possible error was the response time of the researcher and how long it would take the researcher to pause the stopwatch. The average response time of Dugesia tigrina was 0.522 seconds; the response times ranged from “immediate” to 0.90 seconds. A better way to analyze the effects of taurine would be to use vertebrates. As this research project only allotted for the use of invertebrates, researchers could seek to perform a similar experiment on an easily observable vertebrate, such as a rat. In the future, a researcher could further apply these findings by looking at the effects of taurine on memory in the context of the human population.

Acknowledgements Marty Harvill, Ph.D., Senior Lecturer Lauren Graham, Laboratory Assistant Chara Blackwell, Statistician Camila Albo, Research Assistant References [1] Dogar, Mariam. “The Effects of Taurine on Memory Retention in Dugesia Dorotocephala.” Science Review (2014): n. pag. Print.

[2] Sarnat, H. B., and Netsky, M. G. (1985, Nov 12). The Brain of the Planarian as the Ancestor of the Human Brain. Retrieved from http://www.ncbi.nlm.nih.gov/ pubmed/4084864.

[3]Mueller, Caitlin T. “The Use of Classical Conditioning in Planaria to Investigate a Non-neuronal Memory Mechanism.” (2016): n. pag. Web. [4] Mawer, Rudy, MSc, CISSN. “What Is Taurine? Benefits, Side Effects and More.” Authority Nutrition. Authority Nutrition, 18 Aug. 2016. Web. 23 Apr. 2017.

[5]Valleys, Charlotte. “DHA and ARA in Infant Formula Dangerous and Unnecessary—Synthetic Additives Have No Place in Infant Foods.” Cornucopia.org. The Cornucopia Institute, May 2010. Web. [6]Ito, K., Arko, M., Kawaguchi, T., Kuwahara, M., Tsubone.

(2009). “The effect of subacute supplementation of taurine on spatial learning and memory.” Exp. Anim. 58 (2), 175180.

[7]Wasserman, Robin. “What Foods Contain Taurine?”

LIVESTRONG.COM. Leaf Group, 15 Apr. 2015. Web. 23 Apr. 2017.

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Original Research

The Effects of 100mM Ammonium Chloride on Tetrahymena Christian Gomez1, Sydney Gauss1, Anthony Hernandez1, Samantha Hodges2, Will Mullen1, Tamarah Adair,1 Ph.D. 1 Department of Biology, Baylor University, Waco, TX 76798, USA. 2 Institute of Biomedical Studies, Baylor University, Waco, TX 76798, USA.

Abstract Tetrahymena is a type of ciliate that is commonly found in soil ecosystems. Protists, including ciliates, play a critical role in microbial communities by helping regulate components of the soil food web. However, despite the high sensitivity they may have to environmental perturbations, little is known regarding how different chemicals affect ciliates. The purpose of this experiment was to determine if ammonium chloride (NH4Cl) would have an effect on Tetrahymena cell counts after 24 hours of exposure to the compound. NH4Cl is a compound commonly found in fertilizers and used in agriculture across the world. In this study, we treated Tetrahymena with a 100mM concentration of NH4Cl for 24 hours and then performed cell counts for the NH4Cl treated and control wells. After averaging the cell counts for the treatment and control groups, the mean cell count for the treatment group was 3,118 Tetrahymena cells/mL. Furthermore, the average cell count for the control group was 7,538 cells/mL. These findings show that NH4Cl negatively affects Tetrahymena cells and their ability to grow. With this, it is evident that NH4Cl and possibly other components of fertilizers are affecting the ecosystem within the soil. This experiment furthers our understanding of how commonly used products in agricultural and farming may be impacting soil biodiversity.

Introduction Tetrahymena are found in large numbers in many different ecosystems. Specifically, they are abundant in soil ecosystems, and they grow and reproduce rapidly along with having many unique characteristics (Shi, Ma, Xu, Zhang, & Yu, 2012). For instance, they are heterokaryotic with two nuclei, a micronucleus and a macronucleus, and have diverse patterns of cilia that help with movement of the organism (Orias, Cervantes, & Hamilton, 2011). Their role in the soil ecosystem is important because they constitute a major part of the bottom of the food chain by consuming large amounts of bacteria. Keeping bacterial numbers in check is very important in the soil ecosystem, so for that reason Tetrahymena play an essential role within the ecosystem (Hiltunen, Kaitala, & Laakso, 2017). Furthermore, Tetrahymena consume large amounts of bacteria and intake large amounts of ammonium (NH4+). The excess amount of NH4+ is released by the Tetrahymena into the soil, and those nutrients can then be reused by bacteria and other organisms. In most cases, the excess NH4+ can even be absorbed by plant roots.

The nitrogen cycle is an example of how crucial Tetrahymena are to the microbial food web within soil ecosystems and to the environment overall. However, within the soil environment, many substances accumulate and the impact these substances have on ciliate populations is broadly unknown.

We hypothesize that depending on the substance, it can be beneficial or harmful for the Tetrahymena population and

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therefore the food web.

Many fertilizers are consistently introduced to ecosystems within the environment. Some of the most common fertilizers that have been noted to increase vegetable growth are nitrogen and phosphorus fertilizers (Bi et al., 2017). A study conducted by Wang et al. (2017) examined how different concentrations of nitrogen and phosphorus in commonly used fertilizers affected organisms in soil ecosystems. The study discovered that any treatment with nitrogen-containing components such as nitrate (NO3-) negatively affected populations of bacteria and archaea, known as diazotrophs, within the soil that are known to play a key role in nitrogen fixation (Wang et al., 2017). The present study expands on these findings by investigating the specific effect of another component of fertilizers, ammonium chloride (NH4Cl), on Tetrahymena ciliates which are also known to play an important role in the nitrogen cycle.

In this experiment, a 100mM concentration of NH4Cl was introduced to Tetrahymena cultures in order to measure the effects on Tetrahymena cells following 24 hours of exposure to the NH4Cl. NH4Cl is a chemical that is abundant in the soil environment because it is commonly found in fertilizers. For this purpose, NH4Cl was specifically studied to determine if it would affect Tetrahymena cell growth. It was hypothesized that the NH4Cl would inhibit cell growth, resulting in a lower number of cells in the treatment groups compared to the control cultures.

If the hypothesis is supported, this result would suggest that the same may be true in the soil. Decreased numbers of Tetrahymena in the soil could both directly and indirectly have negative effects within the ecosystem Methods and Materials General Experimental Design

Tetrahymena within a proteose peptone tryptone (PPT) media solution were treated with a 100mM concentration of ammonium chloride (NH4Cl) in order to examine the chemical’s effects on cell counts after 24 hours of exposure to the chemical. For comparison, Tetrahymena cultures were grown within a PPT solution without the added NH4Cl. Eighteen identical experiments were performed for a total of 54 measurements, for both the treatment and control wells.

Preparation of Tetrahymena Culture

The stock Tetrahymena pyriformis cells (Carolina Biological Supply Company) were grown in bacteria-free proteose peptone media. Prior to the experiment, baseline cell counts were conducted in order to determine the Tetrahymena stock concentration in cells/mL. Dilutions of the stock culture were made in order to start the experiments with a constant number of cells (1000 cells/mL).

Effects of NH4Cl on Tetrahymena

For each experiment, three control wells and three treatment wells contained 950µL of 1000 Tetrahymena cells in PPT media. For the three treatment wells, 50µL of 2M NH4Cl was added to the PPT media for a final concentration of 100mM NH4Cl. For the control wells, 50µL of water was added for a final volume of 1,000µL in each well.

After 24 hours of incubation with NH4Cl, Tetrahymena cell counts from the treatment and control wells were performed in triplicate for each well. The counts were made in 10µL drops and for some experiments the cells were stained with 10µL of iodine prior to counting in order to view and count the cells more easily under the compound microscope. Eighteen identical experiments were performed for a total of 54 measurements.

Statistical Analysis

All statistics were performed using the Data Analysis ToolPak in Excel. For the control and treatment groups, average cell counts and standard errors were found.

An F-test was performed to examine whether the variances were significant between the groups and a t-test was conducted to determine whether or not the cell counts were significantly different between groups.

Descriptive statistics showed that the mean cell count for the control group was 7538 Tetrahymena cells/ mL and the mean following 24hrs of NH4Cl treatment was 3118 Tetrahymena cells/mL. The standard error calculated for the control group was 3858 cells/mL, while for the treatment group it was calculated to be 2275 cells/mL. The highest average number of Tetrahymena cells/mL in the control group was calculated to be 17,000 cells/mL, while the lowest was 2,300 Tetrahymena cells/mL. This produced a control group range of 14,700 cells/mL. However, in the treatment group, the Tetrahymena treatment cell counts included a maximum count of 8,700 cells/mL and a minimum cell count of 460 cells/mL. This produces a treatment cell count range of 8,240 Tetrahymena cells/mL.

Determined from the F-test, the variances of the control and treatment groups were significantly different (p = 0.02), and therefore a t-test assuming unequal variances was used. The t-test was significant (p = 0.0003), demonstrating that the cell counts for the control and treatment groups differed significantly (Fig. 1). Treatment with NH4Cl significantly decreased Tetrahymena cell counts.

Figure 1. Average Tetrahymena cell counts between the control and treatment groups following 24 hours of exposure to 100 mM NH4Cl. Following exposure of Tetrahymena to NH4Cl (n=54), the number of cells was significantly decreased compared to control sampes (n=54) (p-0.0003).

Data are expressed as mean standard error of the mean (SEM), *p< .05.

Results Effects of NH4Cl on Tetrahymena Cell Counts

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Discussion

The purpose of this study was to examine how a common component of fertilizer, NH4Cl, effected Tetrahymena ciliate populations following 24hrs of exposure to the chemical. The average cells counts for the treatment and control groups varied significantly. The control group had a mean cell count of 7538 cells/mL and the Tetrahymena treated with NH4Cl had an average cell count of 3118 cells/mL. These results demonstrate the negative effects of NH4Cl on Tetrahymena. These findings supported the hypothesis that NH4Cl would inhibit Tetrahymena cell growth. In this experiment, the cell counts were conducted after only one day of exposure to NH4Cl, but fertilizers used by humans for agricultural purposes are most likely applied to soil for much longer than one day and most of the time it is reapplied. This could mean that the effects of NH4Cl discovered in this experiment could have a much broader and extreme effect in our ecosystems.

Another study conducted by Liu et al. (2017) using chemicals involving inorganic mercury components discovered similar results as to what that NH4Cl produced among Tetrahymena populations in this experiment. The inorganic mercury examined is commonly found in the damp environments where many soil ciliates reside just like NH4Cl. Furthermore, the mercury-based chemicals studied seemed to have negative effects on the cell membranes and mitochondrial function of Tetrahymena, which lead to a decreased number of cells (Liu et al., 2017). A slight difference in this experiment compared to this study of NH4Cl is that the inorganic mercury was observed to have been ingested by the Tetrahymena. In this study, it is not for certain how NH4Cl directly affects the physiological functions of Tetrahymena cells, but both experiments demonstrate how commonly found chemicals produce harmful effects on Tetrahymena growth and replication.

Similarly, a different study using another type of ciliate, Paramecium, showed decreased Paramecium cell counts when a chemical containing phosphoramidate was introduced to the treatment populations (Houneida, Berrebah, Berredjem, & Djebar, 2012). Phosphoramidate is a phosphate group that contains an NR2 group instead of an OH group attached to it. Again, a nitrogen containing compound like NH4Cl seemed to have a negative effect on growth and replication for ciliates. The main difference in the study is that the Paramecium treatment groups were exposed to the chemical for 72 hours, and there were no serious effects recorded until 18 hours of exposure had taken place. Furthermore, as more time passed, the effects of the phosphoramidate increased. In our experiment conducted with NH4Cl, the compoundâ&#x20AC;&#x2122;s severe effects were noticed after the Tetrahymena treatment groups were exposed to NH4Cl for only 24 hours. The effects of NH4Cl seem to be much more harmful in terms of inhibiting cell growth, and the phosphoramidate compound studied seemed to have

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the same growth inhibitory effects. The only difference was that the phosphoramidate effects took place after more time passed.

The purpose for investigating NH4Cl is because of its significant relevance in many environments and ecosystems. NH4Cl accumulates in environments due to humans adding fertilizers to lawns and crops. Furthermore, when it rains, the chemicals will travel with the water and end up being absorbed by the soil. The soil that absorbs these chemicals, such as NH4Cl, is home to many soil ciliates like Tetrahymena. Fertilizers appear to be harmless to many people, but this experiment helps demonstrate its effects that we cannot see with the naked eye in environments around us everywhere. Because of this, it is important to be vigilant when using chemicals that most people deem harmless when in fact they can actually be extremely harmful to organism populations.

Together, NH4Cl was observed to be a harmful compound by decreasing Tetrahymena cell numbers and prohibiting their reproduction following 24hrs. of treatment. However, some limitations existed within this experimental design. The outdoor conditions were not replicated, as the experiment took place within a controlled laboratory. Because of this, factors such as temperature and the amount of precipitation could change results in some way.

Regardless, after this experiment, it is evident that NH4Cl is a chemical that has detrimental effects on Tetrahymena populations, which may significantly impact other forms of life within the soil and broader ecosystem.

Acknowledgements The authors would like to acknowledge Dr. Adair for all of her expertise and help throughout the semester in the Ciliate Investigative Learning Initiative (CILI) â&#x20AC;&#x201C; Classroom Undergraduate Research Experience (CURE).

References [1] Bi, Q. F.; Chen, Q. H.; Yang, X. R.; etc. Effects of combined application of nitrogen fertilizer and biochar on the nitrification and ammonia oxidizers in an intensive vegetable soil. AMB Express 2017, 7(1), 198.

[2] Hiltunen, T.; Kaitala V.; Laakso, J. Evolutionary contribution to coexistence of competitors in microbial food webs. Proceedings of the Royal Society 2017, 284(1864).

[3] Houneida, B.; Berrebah, H.; Berredjem, M.; etc. Effect of novel phosphoramidate on growth and respiratory metabolism of Paramecium aurelia. Journal of Natural Science, Biology, and Medicine 2012, 3(1), 48-51. doi: 10.4103/09769668.95949 [4] Liu, C.; Qu, G.; Cao, M.; etc. Distinct toxicological characteristics and mechanisms of Hg2+ and MeHg in Tetrahymena under low concentration exposure. Aquatic Toxicology 2017, 193(Supplement C), 152-159.

[5] Orias, E.; Cervantes, M. D.; & Hamilton, E. P. Tetrahymena thermophila, a unicellular eukaryote with separate germline and somatic genomes. Res Microbiol 2011, 162(6), 578-586.

[6] Shi, J. P.; Ma, C. Y.; Xu, B.; etc. Effect of light on toxicity of nanosilver to Tetrahymena pyriformis. Environ Toxicol Chem 2011, 31(7), 1630-1638.

[7] Wang, Q.; Wang, J.; Li, Y.; etc. Influence of nitrogen and phosphorus additions on N2-fixation activity, abundance, and composition of diazotrophic communities in a Chinese fir plantation. Sci Total Environ 2017, 619-620:1530-1537.

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Original Research

Actigraphy-Defined Sleep Quantity is Associated with Pre-Test Stress, Creativity, and Educational Learning Taylor Terlizzese, Chenlu Gao, Michael K. Scullin, Ph.D. Baylor University, Waco, Texas Abstract Sleep duration and quality are important factors in educational learning, creativity, and stress in college students. With many students receiving an insufficient amount of sleep, there is concern that sleep deprivation could affect academic success. A group of 41 undergraduate students participated in a multi-session study in which they first learned microeconomics concepts and then were tested one week later. Participants also completed tests of creativity and stress rating scales, and we monitored participants’ sleep quantity between sessions by using wristband actigraphy and sleep diaries. We found that students who slept more during the week reported less pre-test stress. Furthermore, there were nominal (but nonsignificant) increases in performance in good sleepers (7-9 hours per night) for the creativity tests and microeconomics questions that required application of learned material. We conclude that sleeping 7-9 hours per night is beneficial to academic performance by increasing the ability to apply learned information, increasing creativity, and decreasing pre-test stress.

Keywords Actigraphy, college students, creativity, educational learning, sleep deprivation, stress Introduction Imagine you have a major exam tomorrow morning and you do not feel prepared. Should you forgo the recommended eight hours of sleep for studying? Do you pass up a night’s rest for another set of practice problems? Many college students will answer “yes” to such questions when faced with the pressures of a heavy academic work load. Sacrificing sleep has become so normal that many students will reduce their amount of sleep or even pull “all-nighters” in order to finish their school work (Noland, Price, Dake, & Telljohann, 2009; Thacher, 2008). On a broader scale, sleep deprivation is associated with negative effects including elevated risks for stroke, heart attack, type II diabetes, and certain types of cancer (Grandner et al., 2010; Kakizaki et al., 2008; Von Ruesten, Weikert, Fietze, & Boeing, 2012). Sleep deprivation also has adverse consequences on psychological processes including increased impulsivity and reduced mood and emotional regulation (Anderson & Platten 2010; Haack & Mullington, 2005; Ju, Lucey, & Holtzman, 2014).

Cognitive effects include reduced memory consolidation, impaired creativity, and difficulty coping with stress (Curcio, Ferrara, & Degennaro, 2006; King, Daunis, Tami, & Scullin, 2017; Pilcher, & Walters, 1997). Further, sleep is necessary for integration of learned principles, especially in

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tasks requiring creative processes (Cai et al., 2009; Lewin & Glaubman, 1975; Walker, Liston, Hobson, & Stickgold, 2002). Even partial sleep deprivation impacts cognitive and motor performance (Pilcher & Huffcuff, 1996). After only 19 hours of sleep deprivation, participants performed with equal cognitive impairments associated with a blood alcohol content of 0.05%. The measured effects included decreased performance on tests of reaction time, tracking, divided attention, and spatial memory (Williamson & Feyer, 2000).

Longer than normal sleep duration (greater than 8 hours per night) is also problematic. The cognitive effects of long sleep duration are not well known; however, longer durations are associated with obesity, diabetes, cardiovascular diseases (Buxton & Marcelli, 2010), and increased mortality in adults (Patel, Malhotra, Gottlieb, White, & Hu, 2006). Therefore, the effects of poor sleep, either too long or too short, may make students unable to thrive in a learning environment.

Unfortunately, students may find that they must budget part of their sleep time to studying and completing their work. Most students often overlook the importance of good sleep quality and quantity, with many students sleeping an average of 5-6 hours per night (Drayton, Gullarr, & Johnson, 2006; Lund, Reider, Whiting, & Prichard, 2010).

Because sleep is vital to memory consolidation, it is no wonder that sleep deprived students demonstrate worse classroom performance (Rasch & Born, 2013). In a group of high school seniors, students who stayed awake longer to study showed worse academic functioning the following day (Gillen-O’Neel, Huynh, & Fuligni, 2013). Moreover, poor subjective sleep quality was associated with a decrease in grade point average by 0.23 points in college students (Gilbert & Weaver, 2010). Time of day also plays a significant role in academic performance (Wile & Shouppe, 2011).

Students tend to perform worse when tested in the early afternoon compared to the morning and late afternoon (Monk, 2005).

The final factor of academic performance discussed that is relevant to our study is stress. Increased levels of stress are associated with decreased academic performance in students (Akgun & Ciarrochi, 2003; Sohail, 2013), particularly in students anxiously anticipating an upcoming test (Cassady & Johnson, 2002). Interestingly, stress may be bidirectionally associated with sleep quality in college students (Lund, Reider, Whiting, & Prichard, 2010). Individuals with greater stress, measured objectively using neuroendocrine responses, show decreased total sleep time (Meerlo, Sgoifo, & Suchecki, 2008). Likewise, individuals who have been sleep deprived show hyperactivity in both the autonomic sympatho-adrenal system and the hypothalamic-pituitary-adrenal axis—systems known to be involved in human stress response (Meerlo, Sgoifo, & Suchecki, 2008). Worse sleep quality may negatively impact mood, resulting in an increased sense of stress (van Eck, Berkhof, Nicolson, & Sulon, 1996). Not all research studies, however, indicate that poor sleep quality is associated with increased stress.

Salivary cortisol levels, an objective measure of stress (van Eck, Berkhof, Nicolson, & Sulon, 1996), were blunted in the presence of a stressor for participants who received objectively worse quality sleep (Backhaus, Junghanns, & Hohagen, 2004; Wright, Valdimarsdottir, Erblich, & Bovbjerg, 2007). One explanation could be because decreased sleep quality results in diminished immune functioning (Bryant, Trinder, & Curtis, 2004). An abated stress response may then result from immune system impairment. Because of the limited amount of research on subjective stress and poor sleep, we have directed our efforts to identify a link between sleep quantity and subjective stress levels.

In our study, we investigated the relationship between sleep duration and academically-relevant outcomes. Specifically, we measured creativity, ability to learn and apply educational principles, and stress state. We hypothesized that reduced

sleep quality and quantity would be correlated with (1) a decreased ability to learn and apply educational material, (2) decreased performance on tasks requiring creative processes, and (3) increased levels of subjective stress.

Methods Participants

The participants were 41 undergraduate students (26 females, 15 males, Mage = 18.9 years, age range 18–20 years) enrolled in psychology classes at a private university.

Participants were recruited through an online program for class credit (SONA Systems, self-selection sampling). The sample consisted of a mixture of Caucasian (63%), Asian/ Pacific Islander (20%), Hispanic (10%), and African American (7%) participants.

Study Design

Participants completed two sessions in a cognitive testing laboratory. During the first session, participants completed a series of questionnaires and cognitive tests and worked through a microeconomics lecture. During the second session, participants were given another series of questionnaires and cognitive tests and took a microeconomics test. The sessions were separated by 7 days and occurred at the same time of day. Between each session, participants wore a wrist actigraphy device and maintained a daily sleep diary.

Procedure During Session 1, participants read and signed an informed consent form. They then completed a pre-task

Short Stress State Questionnaire (Helton, 2004), a demographics questionnaire, the Raven’s progressive matrices test (Raven, Raven, & Court, 1998), the Remote Associates Test (Mednick, 1962), the Alternate Uses Test (Guilford, 1967), and a post-task Short Stress State Questionnaire. They then worked through a microeconomics lecture and took a final post-lecture Short Stress State Questionnaire. Finally, participants were instructed on how to wear their actigraphy device and maintain a Consensus Sleep Diary (Carney et al., 2012), a physical activity diary, and a dietary diary.

During Session 2, participants were given a pre-test Short Stress State Questionnaire and an exit questionnaire. The participants completed a microeconomics test, a post-test Short Stress State Questionnaire, and an alternative version of the Raven’s progressive matrices test, the Remote Associates Test, and the Alternate Uses Test. They were then administered a final post-task Short Stress State Questionnaire. Participants were debriefed and received class credit for their participation.

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Actigraphy Sleep Measurement

Actigraphy is a movement-based tool used to estimate the sleep/wake state of participants. The device (Phillips Respironics – Actiwatch 2) was worn on the wrist for the entire duration of the study to estimate sleep quantity and number of nighttime awakenings. The actigraphy device uses accelerometer and light exposure data to detect the participants’ sleep/wake state. We implemented the factory recommended settings of epoch length (15 seconds) and sensitivity (medium threshold of 40 activity counts for defining wake onset and 10 minutes of immobility for defining periods of rest as sleep).

Sleep, Activity, and Food Consumption Diary

Participants maintained the Consensus Sleep Diary (Carney et al., 2012) throughout the week. The diary consisted of 8 questions answered every day. Their responses were used to identify subjective sleep and wake time, sleep latency, number of awakenings, naps, and sleep quality.

We also gave a diary to participants inquiring about the number of hours they studied, the number of minutes they exercised, and the amount of fruits, vegetables, and fats they consumed each day.”

Figure 1 - Study protocol, the tests in Session 2 were alternative, counterbalanced versions of tests given in session 1.

Figure 2 – Microeconomics equilibrium problem requires the student to shift the supply and demand curve in the appropriate direction and amount in order to calculate the new price and quantity.

Microeconomics Lecture (Session 1)

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Participants engaged in a 30-minute computer based interactive lecture on the topics of supply and demand. The lecture taught how to identify changes in either supply or demand for a given situation. The lecture also taught how to calculate the changes in supply or demand by shifting the respective curve. After each topic was discussed in the lecture, the program gave participants practice problems to test their understanding.

Measures

We administered a 27-question microeconomics test, the Raven’s progressive matrices test, the Remote Associates Test, the Alternate Uses Test, and the Short Stress State Questionnaire. The In the microeconomics lecture test, p required participants to apply what they had learned by answering questions about supply and demand. Participants were required to determine if the scenario presented in the problem affected supply or demand and then shift the curve appropriately to calculate the correct answer.

Participants also completed problems requiring integration of supply and demand. As illustrated in Figure 2, A question would ask participants would have to calculate the new price and quantity given changes in both supply and demand.

The Raven’s Progressive Matrices test is a measure of fluid intelligence (Raven, Raven, & Court, 1998). Participants were shown a pattern of eight complex figures and were asked to predict the next item in the pattern. The test consisted of 18 questions over the span of ten minutes. The Remote Associates Test (RAT) (Mednick, 1962) is a measure of creative thinking which asks participants to link three given words with a common word. For example, the words fur/ rack/ tail would be given and the correct answer would be coat. In order to gather responses from participants of varying creative ability, we selected five very easy items, ten medium difficulty items, and five very hard items to form each Remote Associates Test. Another measure of creativity is the Alternate Uses Test (AUT), which asks participants to provide alternative uses for common items (Guilford, 1967). For example, alternative uses for a shoe could include storing keys, hammering a nail, or stomping on a bug.

The Short Stress State Questionnaire (SSSQ) is a subjective, multidimensional measure of self-reported stress state (Helton, 2004). Participants rated on a five-point scale how much they currently feel certain emotions (e.g., dissatisfaction, depression). The questions are used to indicate subjective levels of stress. The SSSQ was administered six times throughout the two sessions (see Figure 1). When the SSSQ was given before the task, lecture, and test, the form was written using the present tense “I want to succeed on the task.” When the SSSQ was given after the task, lecture, and test, the form was written using the past tense “I wanted to succeed on the task.”

Statistical Analysis

We used t-tests to compare microeconomics test performance between good sleepers and poor sleepers based on their actigraphy data and calculated Cohen’s d to estimate effect size. We also used t-tests to compare microeconomics test performance with time of day. Partial-correlation was used to examine associations between sleep duration and RAT performance. We utilized analysis of variance (ANOVA) to calculate the difference in economics test performance in different time groups. Finally, we used Pearson’s correlation coefficients to examine the relationship between sleep duration and pre-test stress levels. We used an alpha level of 0.05 to determine statistical significance.

Results

Following contemporary professional sleep society recommendation to sleep 7-9 hours/ night (Hirshkowitz et al., 2015; Watson et al., 2015), we classified participants as good sleepers (sleeping 7-9 hours per day on average, n = 18) or poor sleepers (sleeping less than 7 hours or more than 9 hours per day on average, n = 22). The 7-9 hours of sleep per day range was chosen as “good” because it is optimal amount of sleep for young adults and it has been conventionally used in cognitive studies (Ferrara & De Gennaro, 2001). On average, participants scored 83% correct on practice problems throughout the lecture, indicating a basic understanding of microeconomic principles after watching completing the virtual lecture. When given a test one week later with problems covering concepts that students were trained to perform, good sleepers tended performed nominally (but not significantly)to score higher better when thancompared to poor sleepers (t = 1.44, p = .16, d = 0.466, d = 2.91) (Figure 3a). We observed similarA non-significant patternstrend was also observed on microeconomics testthe problems requiring that required integration of learned material (t = .88, p = .39, d = .2752) (Figure 3b) and on . However, the test scores fell short of statistical significance. Further, participants classified as good sleepers demonstrated higher overall Remote Associates TestRAT post-test scores (Figure 4a). The results, albeit nonsignificant, indicated that RAT performance is may be better in good sleepers (r = .27, p = .100), particularly on the items of medium difficulty (r = .29, p = .071). Additionally, testing time of day yielded significant differences. ANOVA indicated higher performance on the microeconomics tests in the morning group (x = 10.9, SD = 6.0) than the early afternoon group (x = 3.3, SD = 3.7) (η2 = 0.15, p = .046, Figure 4b). Finally, participant pre-test stress levels and sleep time are shown in Figure 5. Participants who slept less reported significantly higher levels of stress before the microeconomics test (r = -.35, p = .030). HoweverS, stress levels at other time points were not significantly different associated with sleep durationbetween groups.

Figure 3: Microeconomics tests scores for all problems (a) and integration problems (b) for good and poor sleepers.

Figure 4: Remote Associates Test Scores (a) and the effect of time of testing on Microeconomics test scores (b).

Discussion

We found that good sleepers scored higher on portions of the microeconomics test than the poor sleepers.

Though this medium-sized effect did not reach statistical significance, our finding converges with previous evidence that decreased quality and quantity of sleep impair learning and test performance (Curcio, Ferrara, & Degennaro, 2006).

Some reasons for the relationship being nonsignificant include low statistical power and the moderating impact of the time of day participants were tested. In such case, we believe time of day may be just as, or even more influential than sleep duration.

We also observed evidence that better sleep was correlated with increased creativity (medium-sized correlation). This finding is consistent with the hypothesis that Rapid Eye Movement (REM) sleep is crucial to creativity and integration of learned information (Cai et al., 2009; Lewin & Glaubman, 1975). Because REM sleep time is proportional to total sleep time, decreased sleep duration consequentially decreases time spent in REM sleep in young adults. Sleep duration was also associated with subjective levels of pre-test stress. Previous research indicates that restricted sleep relates to levels of the neuroendocrine stress response (Meerlo, Sgoifo, & Suchecki, 2008).

A fascinating outcome, however, was that only pre-test stress levels were increased, indicating that reduced sleep time may have only influenced stress in the presence of a potential stressor (i.e., an upcoming test they may have

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been thinking about for the past week). Increased stress levels at only the pre-test time likely means decreased sleep duration is linked specifically to increased anticipatory stress. A possible confounding variable could be pre-existing stress (trait-level stress) that results in overall decreased sleep time; however, we would then anticipate stress levels at all time points to be correlated with sleep time. Because only pre-test stress levels from Session 2 were significant, we can conclude trait-level stress was not a significant factor.

Limitations

Though time of day was consistent between the two sessions, we did not randomly assign session time in the current study. Future studies should consider testing at different times throughout the day to replicate our correlational finding. Such studies would benefit from a sample size of at least 30 participants per group to ensure adequate power. Further, we believe REM sleep duration to be an important factor in cognitive performance; however, actigraphy is unable to determine time in REM sleep. Future studies may utilize polysomnography to determine whether reduced REM sleep duration is associated with RAT performance. Moreover, we assessed only a few parameters of sleep quality. The Consensus Sleep Diary asked participants sleep quality questions, such as rating how well they slept on a Likert scale. The diary is a measure both subjective and limited in scope. Because sleep quality is known to affect cognitive processes, future studies may employ the use of other measures of sleep quality such as the Pittsburgh Sleep Quality Index (PSQI), a standard measure of subjective sleep quality (Buysse et al., 1989; Nebes, Buysse, Halligan, Houck, & Monk, 2009), which asks questions about nightly disturbances and medication usage.

Implications

The results of our study indicate that sleep time played an important role in both learning educational material and in creativity performance. Furthermore, we found that reduced sleep time was significantly related to increased levels of anticipatory stress in students. Decreased cognitive performance and increased stress levels are known to be detrimental to academic success, which prompts our concern for the proportion of students who have poor sleep habits. One of the aims of our work is to call attention to the harms of not receiving the recommended eight hours of sleep per night.

As for future work, researchers should investigate how time of day influences educational learning and test performance (Wile & Shouppe, 2011), especially if testing is performed in the early afternoon “dip” (Monk, 2005). We also recommend that future sleep research employ learning materials with ecological validity. In our study, participants were asked to learn and integrate microeconomics material, a task with more ecological validity to the classroom than

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typical laboratory tests of learning, such as memorizing a list of words. The microeconomics task also included problems requiring the integration of learned material, testing the participants’ ability to apply the concepts they learned.

We suggest future research to test students in ways which require application of learned principles.

With our findings in mind, we recommend that students change their study and sleep habits to achieve eight hours of quality sleep every night. Because of the detrimental effects of poor sleep, students should prioritize sleep and forgo the late nights of studying. Our recommendation aims to benefit students in both their academic and psychological well-being. Hopefully our findings will prompt you to put down that textbook and catch a couple more hours of sleep.

If you are not convinced, sleep on it.

References [1] Akgun, S.; Ciarrochi, J. Learned resourcefulness moderates the relationship between academic stress and academic performance. Educational Psychology 2003, 23(3), 287–294.

[2] Anderson, C.; Platten, C. R. Sleep deprivation lowers inhibition and enhances impulsivity to negative stimuli.

Behavioural Brain Research 2011, 217(2), 463–466.

[3] Backhaus, J.; Junghanns, K.; Hohagen, F. Sleep disturbances are correlated with decreased morning awakening salivary cortisol. Psychoneuroendocrinology 2004, 29(9), 1184–1191.

[4] Bryant, P. A.; Trinder, J.; Curtis, N. Sick and tired: Does sleep have a vital role in the immune system? Nature Reviews Immunology 2004, 4(6), 457–467.

[5] Buxton, O. M.; Marcelli, E. Short and long sleep are positively associated with obesity, diabetes, hypertension, and cardiovascular disease among adults in the United States.

Social Science & Medicine 2010, 71(5), 1027–1036.

[6] Buysse, D. J.; Reynolds, C. F.; Monk, T. H.; etc. The Pittsburgh Sleep Quality Index: a new instrument for psychiatric practice and research. Psychiatry Research 1989, 28(2), 193–213.

[7] Cai, D. J.; Mednick, S. A.; Harrison, E. M.; etc. REM, not incubation, improves creativity by priming associative networks. Proceedings of the National Academy of Sciences 2009, 106(25), 10130–10134.

[8] Carney, C. E.; Buysse, D. J.; Ancoli-Israel, S.; etc. The Consensus Sleep Diary: Standardizing prospective sleep self-monitoring. Sleep 2012, 35(2), 287–302.

[9] Cassady, J. C.; Johnson, R. E. Cognitive test anxiety and academic performance. Contemporary Educational Psychology 2002, 27(2), 270–295.

[10] Curcio, G.; Ferrara, M.; Degennaro, L. Sleep loss, learning capacity and academic performance. Sleep Medicine Reviews 2006, 10(5), 323–337.

[11] Drayton, W.; Gullatt, C.; Johnson, L. M. Sleep deprivation among college students. NAAAS Conference Proceedings 2006, 1639–1654.

Continued references [12] Ferrara, M.; De Gennaro, L. How much sleep do we need? Sleep Medicine Reviews 2001, 5(2), 155–179.

[13] Gilbert, S. P.; Weaver, C. C. Sleep quality and academic performance in university students: A wake-up call for college psychologists. Journal of College Student Psychotherapy 2010, 24(4), 295–306.

[14] Gillen-O’Neel, C.; Huynh, V. W.; Fuligni, A. J. To study or to sleep? The academic costs of extra studying at the expense of sleep. Child Development 2013, 84(1), 133–142.

[15] Grandner, M. A.; Jackson, N. J.; Pak, V. M.; etc. Sleep disturbance is associated with cardiovascular and metabolic disorders: Sleep disturbance and cardiometabolic disorders.

Journal of Sleep Research 2012, 21(4), 427–433.

[16] Haack, M.; Mullington, J. M. Sustained sleep restriction reduces emotional and physical well-being. Pain 2005, 119(1–3), 56–64.

[17] Helton, W. S. Validation of a Short Stress State Questionnaire. Proceedings of the Human Factors and Ergonomics Society Annual Meeting 2004, 48(11), 1238–1242.

[18] Hirshkowitz, M.; Whiton, K.; Albert, S. M.; etc. National Sleep Foundation’s sleep time duration recommendations: methodology and results summary. Sleep Health 2015, 1(1), 40–43.

[19] Ju, Y.-E. S.; Lucey, B. P.; Holtzman, D. M. Sleep and Alzheimer disease pathology: A bidirectional relationship.

Nature Reviews Neurology 2013, 10(2), 115–119.

[20] Kakizaki, M.; Inoue, K.; Kuriyama, S.; etc. Sleep duration and the risk of prostate cancer: The Ohsaki Cohort Study. British Journal of Cancer 2008, 99(1), 176–178.

[21] King, E.; Daunis, M.; Tami, C.; etc. Sleep in studio based courses: Outcomes for creativity task performance.

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[22] Lewin, I.; Glaubman, H. The effect of REM deprivation: is it detrimental, beneficial, or neutral? Psychophysiology 1975, 12(3), 349–353.

[23] Lund, H. G.; Reider, B. D.; Whiting, A. B.; etc. Sleep patterns and predictors of disturbed sleep in a large population of college students. Journal of Adolescent Health 2010, 46(2), 124–132.

[24] Mednick, S. The associative basis of the creative process. Psychological Review 1962, 69(3), 220–232.

[25] Meerlo, P.; Sgoifo, A.; Suchecki, D. Restricted and disrupted sleep: Effects on autonomic function, neuroendocrine stress systems and stress responsivity. Sleep Medicine Reviews 2008, 12(3), 197–210.

[26] Monk, T. H. The post-lunch dip in performance. Clinics in Sports Medicine 2005, 24(2), e15–e23.

[27] Nebes, R. D.; Buysse, D. J.; Halligan, E. M.; etc. Self-Reported sleep quality predicts poor cognitive performance in healthy older adults. The Journals of Gerontology: Series B 2009, 64B(2), 180–187.

[28] Noland, H.; Price, J. H.; Dake, J.; & etc. Adolescents’ sleep behaviors and perceptions of sleep. Journal of School

Health 2009, 79(5), 224–230.

[29] Patel, S. R.; Malhotra, A., Gottlieb, D. J.; White, D. P.; etc. Correlates of long sleep duration. Sleep 2006, 29(7), 881–889.

[30] Pilcher, J. J.; Huffcutt, A. I. Effects of sleep deprivation on performance: A meta-analysis. Sleep 1996, 19(4), 318–326.

[31] Pilcher, J. J.; Walters, A. S. How sleep deprivation affects psychological variables related to college students’ cognitive performance. Journal of American College Health 1997, 46(3), 121–126.

[32] Rasch, B.; Born, J. About sleep’s role in memory. Physiological Reviews 2013, 93(2), 681–766.

[33] Raven, J.; Raven, J. C.; Court, J. H. Manual for Raven’s Progressive Matrices and Vocabulary Scales.

Sohail, N. (2013). Stress and academic performance among medical students. J Coll Physicians Surg Pak 1998, 23(1), 67-71.

[34] Thacher, P. V. University Students and the “All Nighter”: Correlates and patterns of students’ engagement in a single night of total sleep deprivation. Behavioral Sleep Medicine 2008, 6(1), 16–31.

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Original Research

Effects of Differing Insulin Concentrations on Tetrahymena After 24-hour Exposure Kaitlyn Armijo, Kaitlyn Clevenger, Kimberly Imoh, Evelynne Morris, Felicia Osburn, Hope Willenborg, and Tamarah Adair, Ph.D. Baylor University Abstract Healthy soil ecosystems are necessary for human health and survival because they provide clean water and air as well as the nutrients needed to grow food. Insulin is a rising drug in the pharmaceutical industry that could potentially harbor many harmful effects on soil ecosystems. This project investigates the effect that insulin in the environment may have on soil ecosystems by testing three different concentrations of this chemical on the ciliate, Tetrahymena in 1-milliliter cultures.

The number of cells present were counted before and after 24-hour exposure to insulin and compared to a control group.

The results indicate that a low concentration of insulin does not result in a change in cell survival or reproduction, but an insulin concentration over 5.97 x10-6 µmol/mL lowers cell survival. Interestingly, an insulin concentration of 5.97 x10-7 µmol/mL resulted in a significant increase in the number of Tetrahymena in the treatment group (p<0.05). Further studies are needed in order to explore the mechanisms of insulin toxicity and the relevance of insulin levels found in wastewater and contaminated soils.

Keywords soil health, Tetrahymena, insulin Introduction Soil is the source in which food is grown, making it directly relevant to the topic of human health. Soil contains different types of chemicals and nutrients that directly contribute to its health. Varying concentrations of these chemicals may have a positive, negative, or neutral effects on organisms.

Chemicals enter the soil as a byproduct of daily life and impact the soil’s ecosystem. This potentially has long-lasting repercussions on the environment such as pollution and soil contamination. Soil pollution occurs when components of the soil are at a higher level than what is considered normal (usually as a result of human activity), whereas contamination includes a deterioration of the health of organisms present within the soil [6].

Tetrahymena, ciliates from the class Oligohymenophorea, live in the third trophic level along with other organisms including flagellates, shredders, and fungal feeders. This trophic level receives nutrients from the soil and is therefore directly impacted by components found in the surrounding soil including chemicals [5]. Tetrahymena are commonly used in toxicology research today as model organisms and thus can easily be compared to other organisms [8, 11]. For example, experimental results can be extrapolated to what may happen to the ciliates in soil ecosystems. [12]. Ciliates are commonly used in wastewater

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treatment plants as bioindicators and more recently for testing environmental quality [9]. With ciliates fast reproduction rate (about a 2-3 hour doubling time) and inexpensive costs, they allow many tests to be run in a short time period [11].

Since the environment takes in chemicals every day, the effects need to be studied for preventative and protective measures. Once these chemicals reach inhibiting or toxic levels, they influence an organism’s ability to function.

When the ability of an organism is impacted, the soil ecosystem will be affected, in turn altering overall soil diversity.

Similarly, poor land management caused by human activities affects soil biodiversity. This prevents its ecosystem from functioning properly, resulting in a reduction of clean air and water as well as an increase of pathogens [14]. Human activities that have the potential to impact soil diversity include nitrogen deposition, exploitation of land or land products, improper disposal of waste, and climate change [10]. These everyday actions influence the microorganisms in the soil which may impact the overall health of the soil.

Once soil health is impaired, many necessary resources for human health are impacted including clean air, clean water, and nutrient-rich food. One area of environmental pollution is pharmaceutical waste, which may consequentially alter soil health [14].

Insulin is a chemical with increasing prevalence in society due to the drastic increase of diabetes [3]. With this in mind, insulin may potentially become more prominent within soil ecosystems over time. There is a possibility of insulin being introduced into the environment due to the fact that water treatment plants cannot filter out all organic compounds and chemicals from bodily excretions before allowing water to re-enter the environment [1]. The remaining traces of insulin in the environment could potentially build up over time and affect the organisms within the ecosystem. A study conducted in Kuwait determined that endocrine disrupting compounds in the environment that have not successfully been removed from treatment plants do have the capability of returning to the environment.

These chemicals were found in the hepatic tissue of fish living in the surrounding environment demonstrating how chemical pollutants reenter the environment and impact organisms [2].

Although insulin may not be stable in the environment, with increased usage it’s concentration in wastewater may increase. Insulin’s primary function is to regulate blood sugar levels through cell signaling and may have an impact on other organisms’ pathways [8]. Therefore, this experiment measures the survival rate of Tetrahymena using three concentrations of insulin. These results may elucidate the effect, if any, of insulin on soil health.

mL) affects ciliate survival rates. In each concentration, six wells of a twelve-well plate are used as the dilution site to contain each sample. Three wells contain a solution with insulin, and three other wells contain a solution with sterile D.I. water. The first treatment group added 1µl insulin to 999µl ciliate-PPT solution creating an insulin concentration of 5.97x10-8 µmol/mL. This trial contained 15 control groups and 15 treatment groups. In the following trial, 10µl insulin was added to 990µl ciliate-PPT solution creating an insulin concentration of 5.97x10-7µmol/mL. This trial contained 15 control groups and 15 treatment groups. The final trial added 100µl insulin to 900µl ciliate-PPT solution creating an insulin concentration of 5.97x10-6µmol/mL. This treatment trial contained 24 control groups and 24 treatment groups.

Each well plate used was mixed with a sterile micropipette tip to ensure that each treatment was fully immersed in the Tetrahymena media solution. A 10 µl drop was extracted and pipetted onto a concavity slide and observed under a compound microscope. An average cell count was calculated by counting the number of living cells in three 10µl drops from each replicate. The wells of each well plate were covered and stored in the dark at standard room temperature (25 °C) for 24 hours. After 24 hours, the counting procedure was repeated.

Methods Preparation of Ciliates The culture used for the experiment was prepared from a stock culture of Tetrahymena. Four hundred and fifty microliters of proteose-peptone-tryptone (PPT) media was pipetted into three wells of a twelve-well plate, then 50µl of a thoroughly mixed stock culture of Tetrahymena was added to the media in the first well. An additional two 10-fold dilutions were made. Multiple 10µl samples of PPT diluted within the Tetrahymena media were viewed under a compound microscope and the number of ciliates present was recorded and used to produce a culture of 1000 cells/mL.

Statistical Analysis The average number of ciliates in their respective treatment groups were calculated by adding the number of cells in each group and dividing the total by the number of trials conducted. The optimal dilution for cell counting was

found by testing multiple dilutions and choosing the dilution which resulted in a total of 20-200 cells. A two-tailed F-test and t-test were conducted for each treatment group. These tests allowed us to determine the true p-value and whether the experiment rejects or fails to reject the null hypothesis.

Characterization of Insulin The Insulin used was “Pharmacy Relion Humulin”. The insulin used was Pharmacy Relion Humulin (stock concentration of 100 units/mL). The concentration for each unit of insulin is 5.97 x10-9 µmol/mL For each treatment group, insulin was added to a total of 1 mL of stock culture (1000 cells/mL). The low treatment group consisted of 1 µl (0.1 units), the medium treatment group was 10 µl (1unit) and the high treatment group 100 µl (10 units).

General Experimental Design Tetrahymena have insulin receptors similar to humans which are required for survival [13]. This research tests how different concentrations of insulin (0.1, 1.0 and 10.0 units/

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Results Ciliates

Each well began with an average cell count of 1000 cells/mL. After 24-hour exposure to either water or insulin, the cells were recounted. The ciliates exposed to 1 unit of insulin (low) had an average cell count of 2.0 x104 compared to the control cell count of 1.9x104 cells. The ciliates exposed to 10 units of insulin (medium) had an average cell count of 3.8x104 cells compared to the control cell count of 1.9x104 cells. The ciliates exposed to 100 units of insulin (high) concentration had an average cell count of 1.1x104 cells compared to the control cell count of 3.7x104.

Insulin

The three different insulin concentrations had varying results. The lowest concentration of insulin (1 unit) was not statistically significant. The average cell count for the cells receiving the medium treatment (10 units) was significantly higher than the control, whereas the cell counts from the cells receiving the highest concentration of insulin (100 units) were significantly lower than the control (Figure 1).

Statistical Analysis

The normal distribution of cells is depicted in the QQ plots [Figure 2]. These plots show that the data is plausible and follows a normal distribution. The treatment group exposed to 1 unit of insulin had a p-value of 0.7318, allowing the hypothesis to fail to be rejected. There was no statistical significance between the treatment group with the lowest concentration of insulin and its control group (p>0.05). The treatment group exposed to 10 units of insulin had a p-value of 0.0032 which allowed the hypothesis to be rejected.

The number of cells after a 24-hour exposure had statistical significance when exposed to the medium insulin concentration (p<0.05). The treatment group exposed to 100 units of insulin had a p-value of less than 0.0001 which allowed the hypothesis to be rejected. The exposure to the highest insulin concentration demonstrated statistical significance. The average number of cells increased when exposed to 10 units of insulin, but decreased when exposed to 100 units of insulin.

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.

Table 1: This descriptive data shows the mean, median, standard deviation, variance, and range. The T-Stat measures how extreme the statistical estimate is. The F-Stat measures the means between two populations. The P-value measures whether the results were statistically significant (P-value < 0.05) or not statistically significant (P-value > 0.05).

Figure 1: This QQ Plot represents the normal distribution ofTetrahymena cell counts after 24 hour exposure to an insulin concentration of 5.97 x10-8 Âľmol/mL. n=15

Figure 2: This QQ Plot represents the normal distribution of Tetrahymena cell counts after 24 hour exposure to an insulin concentration of 5.97 x10-7Âľmol/mL. n=15

Figure 3: This QQ Plot represents the normal distribution of Tetrahymena cell counts after 24 hour exposure to an insulin concentration of 5.97 x10-6Âľmol/mL. n=24 Discussion This study was performed to further understand the implications of insulin on the soil ciliate, Tetrahymena. In this study, a significant difference was noted in the survival rates of Tetrahymena after 10 and 100 units of insulin were administered to the treatment group (p<0.05). Upon analyzing the data, it became evident that the potential impact is also dependent on the amount of insulin used to treat the culture. The samples treated with 1 unit of insulin showed no significant difference between their treatment and control groups (p>0.05) whereas the samples treated with 10 units of insulin noted a significant increase in the treatment group rather than the control (p<0.05). These factors have been revealed to vary inversely, suggesting that increasing the amount of insulin could increase cell proliferation and after a certain threshold may restrict their growth. These findings align with a study conducted on the extremophile nature of ciliates which discusses a maximum community capacity of ciliates in acidic areas that similarly contributes to the idea that there is a threshold to ciliate proliferation in overbearing conditions [4].

When referencing the data, the t-stat of -0.3462 for the group with the lowest insulin concentration supports the conclusion that not enough insulin was present for the growth factor to cause a change in cell counts. In addition,

the p-value of 0.7318 fails to reject the null hypothesis. In the trial testing the medium concentration of insulin, there was a significant difference among the collected results as shown in the t-stat of -3.3586 (p<0.05) (Figure 1). Adding 10 units of insulin to the ciliate-PPT solution confirms that this is a large enough concentration to have significant results. The null hypothesis was rejected following the calculation of the p-value (p=0.0032). In the last treatment group, the addition of 100 units of insulin significantly decreased the Tetrahymena cell count with a t-stat of 7.9265 and a p-value less than 0.0001.

This project, amongst many others, relays the importance of pharmaceutical regulation and could be the basis of influencing other research. Bureaucratic agencies such as the EPA (Environmental Protection Agency) and the FDA (Food and Drug Administration) rely on this information to lobby officials into writing laws accordingly.

Other countries, more specifically Germany, have reviewed studies on preserving soil fertility and productivity and in turn, have passed legislation such as the German Federal Soil Protection Act (FSPA). The FSPA enforces safety measures on agricultural land use which has significantly diminished the prevalence of soil pollution in Germany [7].

Implementing similar legislation in the United States would lead to an overall increase in soil health therefore positively influencing agricultural output.

Possible errors that may have occurred during this experiment include human error when counting the Tetrahymena, the use of non-sterilized tools, and the process of storing the well plates. The counting of the Tetrahymena was the most feasible human error among the data because there were up to hundreds of Tetrahymena in each drop which required a series of dilutions. This allows room for sampling bias due to random pipetting errors and inaccuracies when using microscopic observations, such as, counting a Tetrahymena twice or missing one. Laboratory error could have also been introduced by not using sterilized tools during this experiment. The use of non-sterile tools added risk because of the possibility of introducing outside pathogens which could have had an effect on the survival outcome of Tetrahymena.

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If the experiment were to be replicated, error should be reduced as much as possible. This includes counting the same sample for each trial multiple times to ensure accuracy and using sterilized tools to determine whether or not this would have any effect on the survival rate of the Tetrahymena after 24 hours. Also, adding additional treatment groups to determine the ciliate’s insulin threshold.

More trials should be conducted in future experiments.

The investigation of the waste disposal path of insulin should be conducted to determine the breakdown products from this protein. Other variables that could be tested for future studies include: determining the effects of varying amounts of other chemicals found in soil such as calcium or nitrogen (from calcium or nitrogen deposits) and their products on the survival rates of Tetrahymena, the effects of light exposure on the survival rates of Tetrahymena, the effects of introducing an outside organism on the survival rates of Tetrahymena, and the effects of soil composition on Tetrahymena survival rates.

References [1] (1998). How Wastewater Treatment Works…The Basics.

United States Environmental Protection Agency. https:// www3.epa.gov/npdes/pubs/bastre.pdf [2] Al-Jandal, N., Saeed, T., Azad, I., Al-Subiai, S., Al-Zekri, W., Hussain, S., & Al-Hasan, E. (2018). Impact of Endocrine Disrupting Compounds in Sewage Impacted Coastal Area on Seabream. Ecotoxicology and Environmental Safety, 150, 280–288. https://www.sciencedirect.com/science/article/pii/ S0147651317308710?via%3Dihub#bib55 [3] Forouhi, N. G., & Wareham, N. J. (2014). Epidemiology of Diabetes. Medicine, 42. https://www.sciencedirect.com/ science/article/pii/S1357303914002710?via%3Dihub [4] Hu, X. (2014). Ciliates in Extreme Environments. Journal of Eukaryotic Microbiology, 61(4), 410–418. https://doi.org/10.1111/jeu.12120 [5] Ingham, Elaine R., Moldenke, Andrew R., & Edwards, Clive A. (1999). Soil Biology Primer. United States Department of Agriculture, A1-H8. https://www.nrcs.usda.gov/ wps/portal/nrcs/detailfull/soils/health/biology/?cid=nrcs142p2 053868 [6] Knox, A.S., Gamerdinger, A.P., Adriano, D.C., Kolka, R.K., & Kaplan, D.I. (1999). Sources and Practices Contributing to Soil Contamination. American Society of Agronomy, 37, 53-87. https://www.srs.fs.usda.gov/pubs/ja/ ja_knox001.pdf [7] Lebert, M., Böken, H., & Glante, F. (2007). Soil Compaction—Indicators for the Assessment of Harmful Changes to the Soil in the Context of the German Federal Soil Protection Act. Journal of Environmental Management, 82(3), 388–397. https://doi.org/10.1016/j.jenvman.2005.11.022 [8] Lynn, D (2009). Ciliates. Protists. Elsevier Inc., 578-592.

[9] Pawlowski, J., Lejzerowicz, F., Apotheloz-Perret-Gentil, L., Visco, J., & Esling, P. (2016). Protist Metabarcoding and

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Environmental Biomonitoring: Time for Change. European Journal of Protistology, 55, 12–25. https://www.sciencedirect.com/science/article/pii/S0932473916300037 [10] Pfützner, A., Musholt, P. B., Malmgren-Hansen, B., Nilsson, N. H., & Forst, T. (2011). Analysis of the Environmental Impact of Insulin Infusion Sets Based on Loss of Resources with Waste. Journal of Diabetes Science and Technology, 5(4), 843–847. https://www.ncbi.nlm.nih.gov/ pmc/articles/PMC3192587/ [11] Ruehle, M.D., Orias, E., & Pearson, C.G. (2016). Tetrahymena as a Unicellular Model Eukaryote: Genetic and Genomic Tools. Genetics, 203, 2, 649–665. https://www. ncbi.nlm.nih.gov/pmc/articles/PMC4896184/ [12] Sauvant, N.P., Pepin, D., & Piccinni, E. (1999). Tetrahymena pyriformis: A Tool for Toxicological Studies.

A review. Chemosphere, 38, 7, 1631-1669. http://www. sciencedirect.com/science/article/pii/S0045653598003816 [13] Shemarova, I.V., Selivanova G.V., & Vlasova, T.D. (2002). The Influence of Epidermal Growth Factor and Insulin on Proliferation and DNA Synthesis in Ciliates Tetrahymena pyriformis. Institute of Evolutionary Physiology and Biochemistry RAS, St. Petersburg. https://www.ncbi. nlm.nih.gov/pubmed/12561730

[14] Wall, Diana H., Nielsen, Uffe N., & Six, Johan (2015). Soil Biodiversity and Human Health. Nature, 528, 7580. https://www.nature.com/articles/nature15744

Original Research

Body Mass Index, Body Image, and Total Wellness in College Women Georgie Hendrickson Baylor University, Waco, Texas Abstract The objective of this research is to examine the relationship that body mass index (BMI) has with various factors, including: self-esteem, depression, close friendships, GPA, social media consumption, childhood diet and exercise, and current exercise. A survey was administered to 130 college women at Baylor University. Participants were analyzed based on the BMI categories of underweight, healthy, overweight, and obese. The results show that obese women tend to have fewer close friends, lower GPA, and generally had an unhealthy childhood, when compared to women of other BMI categories. It was also found that women who are in the categories of healthy weight, overweight, and obese view their bodies as insufficient when comparing themselves to the way women are portrayed on social media. The findings indicated that many aspects of a female’s life could be influenced by her weight.

Introduction “I hate the way my thighs look in my new jeans. I really need to lose a few pounds.” These are typical words spoken by young women who can be quick to criticize their bodies and form a poor body image from trivial observations. Some young adults have a skewed perception of their body because of the influences around them, including friends, parents and the media (Posavac, Posavac, & Posavac, 1998). The mental health of a woman can suffer when she views herself in a negative way (Posavac, Posavac, & Posavac, 1998).

Very often women feel pressured to meet the exceedingly high standards that society has set (Posavac, Posavac, & Posavac, 1998). It is nearly impossible to flip through a magazine or watch a television show without seeing women that have the “ideal body”. Even women that have a healthy body mass index can still feel that their bodies are inadequate compared to women portrayed in the media or to their peers (Posavac, Posavac, & Posavac, 1998).

Body Mass Index (BMI) uses height and weight to find the amount of stored body fat in a person (Streeter, Milhausen, & Buchholz, 2012). It is a common measure of general health. Some women have adopted a weight-influenced self-esteem, in which they assess their self-worth primarily from their weight (Dijkstra, Pieternel, Barelds & Brummen-Girigori, 2015). Body image can affect all areas of one’s life and may change the way a person interacts with others (Dijkstra, Pieternel, Barelds & Brummen-Girigori, 2015).

Studies are now showing that body mass index and mental health are related (McLaren, Beck, Patten, Fick, &

Adair, 2008). The aim of this study is to explore how BMI relates to mental wellbeing, body image, and social competence in college-aged women. This study extends existing research by focusing on college women and how many areas of young women’s live can be affected by their weight. This study investigates the relationship of obesity to self-esteem, depression, close friendships, and GPA. Other factors considered are social media consumption, childhood diet and exercise, and current exercise.

There is prior research pertaining to body mass index, body image, and mental health in women. This section outlines some of the key findings in these areas as well as other issues that are in need of further research. Sand, Nina, and Olaug studied the relationship among BMI, self-esteem, and other issues that young women face. Twelve women, ranging in ages of 22 to 25, were interviewed. Half of them were overweight and half were of a healthy weight. Young women who were overweight were more sensitive and vulnerable to the impact that appearance can have on one’s life. These women were more likely to criticize themselves and form a poor body image. Overweight women generally knew the negative consequences that their weight could potentially have on their health and future. Some of these women made a conscious effort to lose weight, while others did not think it was realistic and did not attempt to change their habits. Other research also finds that women who have a body mass index that falls in the overweight or obese range have a lower body image and self-esteem than other women (Streeter, Milhausen, & Buchholz, 2012).

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These studies show that body mass index is inversely proportional to body image and self-esteem.

Mental health is affected by weight (McLaren, Beck, Patten, Fick, & Adair, 2008). Obese females who struggle with weight control have an increased likelihood of suicidal thoughts (Yeong, 2016). These women have tried to lose weight, but continually gain weight, leading them into depression, which can sometimes result in suicide (Sand, Emaus & Olaug, 2015). Mood disorders are also more prevalent in obese women verses women of normal weight (McLaren, Beck, Patten, Fick, & Adair, 2008). Society puts a high value on being thin, which could cause overweight women to form mood disorders. Conversely, it is possible that emotional eating from a mood disorder would lead to weight gain and obesity (McLaren, Beck, Patten, Fick, & Adair, 2008). Obese women experience a higher rate of depression (Sand, Emaus & Olaug, 2015).

Several studies show that being physically active can decrease depression, improve mental health, and increase self-esteem as well as body image (Monteir, Novaes & Santos 2014). Physically active women tend to have a more positive body image than women who do not exercise (Monteir, Novaes & Santos 2014). Women of normal weight believe it is more important to be active and gain muscle than to just appear lean (Sand, Emaus & Olaug, 2015). These women also think that having a support system and friends to keep them accountable has kept them healthier (Sand, Emaus & Olaug, 2015). In addition, they express that the topic of being overweight is sensitive and needs to be handled with delicacy when discussed, even though they do not struggle with this issue (Sand, Emaus & Olaug, 2015). Thus, weight and appearance are sensitive matters for almost all women.

Even though women with different weights have varying views of their bodies, they agree on some ideas.

Both overweight and women of healthy weight find that the main motive to lose weight is the desire to become healthier, not to look thinner (Sand, Emaus & Olaug, 2015). It is a consensus from women of all weights that there is not a true representation of a “normal female body” in the media (Sand, Emaus & Olaug, 2015). They feel that this should be changed to embody a more realistic view of women (Sand, Emaus & Olaug, 2015). Most women think that there will be a change in the future regarding the public perception of body image and the standards society has set (Sand, Emaus & Olaug, 2015). A trend is beginning to emerge that is creating positive body culture and encouraging women to be confident in their appearance (Sand, Emaus & Olaug, 2015).

The media can play a critical role in how young women develop and view themselves. Interestingly, it has been found that the amount of time spent consuming various types of media does not have an impact on body dissatisfaction (Bell & Dittmar, 2011). Poor body image is associated with the extent to which a young woman identifies with the female being portrayed in the media (Bell & Dittmar, 2011). In the research by Sand et al., overweight

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women expressed that they have felt deeply offended by how the media portrays women of their weight. They also felt that the media influences people to label and judge others based solely on their body shape and appearance.

Exposure to thin females in the media is correlated with weight concerns in young women (Posavac, Posavac, & Posavac, 1998). The media has set an egregious standard for the ideal female body. These expectations coupled with the professional photography and retouching techniques used by the media, make it nearly impossible for most women to meet the criteria. When young women compare their body and appearance to the level of extremity promoted by society, they tend to be more dissatisfied with their body (Du, 2015). However, media exposure will not affect all women, especially those who are already confident in their skills and abilities no matter their weight (Posavac, Posavac, & Posavac, 1998).

There is a high importance placed on appearance and attractiveness in society for young women, which contributes to them being more susceptible to eating disorders (Dijkstra, Pieternel, Barelds & Brummen-Girigori, 2015).

Weight-influenced self-esteem is a key contributor to females with anorexia nervosa and bulimia nervosa (Dijkstra, Pieternel, Barelds & Brummen-Girigori, 2015). Physical appearance, therefore, can influence the social lifestyle a young woman has, which adds pressure to have an ideal body (Posavac, Posavac, & Posavac, 1998). Weight-influenced self-esteem can affect all areas of one’s life, including relationships, work and overall well-being (Dijkstra, Pieternel, Barelds & Brummen-Girigori, 2015). These women criticize every small variance in their appearance and weight, which leads to lower self-esteem and body image (Dijkstra, Pieternel, Barelds & Brummen-Girigori, 2015). Weight can likewise impact popularity, performance in school and intelligence (O’Dea, 2016). Overweight women have lower self-concepts and not as many close friendships as women of healthy weight (O’Dea, 2016).

Being overweight or obese as a child can influence the mental and physical health of that person (O’Dea, 2016). Adolescence is a critical time for development and formation of habits. There is a great range of aspects that are affected by being overweight as a child and these can also influence their lives as adults (O’Dea, 2016). Overweight children are more likely to have physiological and emotional issues, which can be a result of bullying and the stigma that is connected to being overweight (O’Dea, 2016). Obesity in children is associated with many health risks that can be long term, causing childhood obesity to become a challenging issue for our society (O’Dea, 2016). Further research is needed to investigate the long-term correlation between overweight children and how it affects their development into adulthood.

Even though several aspects of the topics of body mass index, body image, and mental health have been thoroughly researched, there are still areas that are in need of further exploration. It has been found that poor body image is correlated to having a BMI in the overweight or obese range (Streeter, Milhausen, & Buchholz, 2012). There is not sufficient information regarding the progression of poor body image. Do young women become overweight because they have a poor body image, or if they were overweight did they then form a poor body image (Streeter, Milhausen, & Buchholz, 2012)? There is a need for research pertaining to the areas of food preferences, physical activity, and body size perceptions for overweight young women (Sand, Emaus & Olaug, 2015). More research also needs to be conducted to investigate how a person can maintain and encourage others to have a positive body image (Sand, Emaus & Olaug, 2015).

Hypotheses Numerous studies point to an inverse relationship between BMI and self-esteem and self-worth. Many factors play into this correlation, including media consumption, exercise and mental health. The first hypothesis (H1) is that as BMI increases in college women, their view of themselves to be a person of high value and worth decreases. Many women form a poor body image, especially women who are overweight (McLaren, Beck, Patten, Fick, & Adair, 2008). The second hypothesis (H2) is that as BMI increases, college women are more likely to dislike their appearance.

The media plays a major influence in how young women view their body and how they develop an opinion of how a woman should look. There is a high importance placed on being thin and having a good appearance in society (Dijkstra, Pieternel, Barelds & Brummen-Girigori, 2015).

The media has set a nearly unattainable standard for young women, making it easy to form a poor body image. Women of higher BMIs tend to be more likely to view themselves in a negative way (Dijkstra, Pieternel, Barelds & Brummen-Girigori, 2015). Because of these findings, it was hypothesized (H3) that college women who are in the overweight or obese categories are more likely to view themselves in a negative way when comparing their bodies to women portrayed in the media.

Women who are overweight are more likely to have mental health problems and experience suicidal thoughts (Yeong, 2016). Mood disorders are more commonly found in obese and overweight women (McLaren, Beck, Patten, Fick, & Adair, 2008). This correlation leads to a fourth hypothesis (H4): college women who have a BMI in the overweight and obese range are more likely to have depression or a mood disorder.

Women with high BMIs do not have as great of a social competence as women with low BMIs (O’Dea, 2016).

Women who are overweight tend to be shy and introvert-

ed (O’Dea, 2016). Therefore, it is hypothesized (H5) that college women with high BMIs do not have as many close friendships as women with average or low BMIs. There is additional research that claims that women who are overweight are less likely to perform well in school (O’Dea, 2016). Because of this, the sixth hypothesis (H6) is that college women with increased BMIs will have lower GPAs compared to college women with healthy BMIs.

The habits people form and choices they make as children affect their health into adulthood (O’Dea, 2016).

Overweight children are more likely to have physical and mental issues as they age (O’Dea, 2016). From this research, it is hypothesized (H7) that overweight and obese women are more likely to have not exercised regularly and eaten healthy as a child.

As young women exercise more frequently, they form a higher body image and view themselves in a positive way (Monteir, Novaes & Santos 2014). Exercise allows people to hold themselves accountable for their own health.

People who exercise regularly tend to look more physically fit, which increases their confidence in their appearance. In a previous study, some overweight and obese women made a conscious effort to lose weight, while others did not think it was realistic and did not attempt to change their habits (McLaren, Beck, Patten, Fick, & Adair, 2008). The final hypothesis (H8) is that underweight and healthy weight women exercise more frequently than overweight and obese women.

Methodology

The hypotheses were with a survey conducted at Baylor University in March 2017. The survey was administered to women in multiple sections of Introduction to Sociology. The participants took an anonymous survey through Qualtrics, an online survey system. The total number of participants was 130. The survey asked for the participant’s height and weight, which was used to calculate BMI. BMI values were used to split respondents into categories of underweight (BMI values of 0 to 18.4), normal weight (BMI values of 18.5 to 24.9), overweight (BMI values of 25 to 29.9) and obese (BMI values of 30 and above).

Seven questions asked the participants to give a response based on the ranking of strongly agree, agree, disagree, and strongly disagree. These questions pertained to self-esteem, media consumption, mental health, and overall healthiness as a child. The survey also asked how frequently respondents exercise. In order to gauge social competence and success in school, the survey asked respondents to include their number of close friendships and their GPA. The appendix lists all survey questions.

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Results

Before testing hypotheses, the weight categories were reported of the survey participants. Underweight females accounted for 6% of the sample (8 participants), women of healthy weight made up 59% (76 participants), overweight females were 25% of the sample (33 participants), and obese females made up 10% (13 participants).

The first survey question asked if women feel that they are a person of worth or value. Table 1 shows that 90.77% of females view themselves to be a person of worth and high value. The vast majority of young females do believe they are a person of value, regardless of weight. The group that was most likely to disagree was females who are obese. There were 30.77% of obese females that did not agree with the idea that they have value and worth, compared to less than 13% of participants in any other weight category. The Chi-square test of significance shows that the relationship between weight category and perception of worth is not statistically significant. Even though there was a difference in the responses across weight categories, it was not large enough to be statically significant so the hypothesis is not supported.

Table 1: Participant responses on measure of personal worth and value

The second question asked participants to respond to the statement “I like my physical appearance.” According to Table 2, 58.46% of the total participants strongly agree or agree that they are fond of their appearance. The weight category that was most likely to disagree with that statement was the obese participants; 76.92% of the obese females strongly disagree or disagree with the statement that they like their physical appearance. This supports the second hypothesis, that as BMI increases, women are more likely to dislike their appearance. Overweight women are more likely to criticize themselves and form a poor body image (Sand, Emaus & Olaug, 2015). The chi-square test of significance shows that the relationship between body weight and liking physical appearance is statistically significant at a p-value of less than .10. That means that this test is 90% confident that the relationship did not occur by chance and is statically significant.

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Table 2: Participant responses to the item, “I like my physical appearance.”

Table 3 shows responses for the item “I feel like my body is not sufficient when I compare myself to the way women are portrayed in the media.” Overall, 81.54% of women do not feel that their body is sufficient when they compare themselves to the way women are portrayed in the media. According to another question in the survey, 90% of participants view women on some form of media everyday. The standards that the media has set for women have influenced women of all sizes to believe that their bodies are not sufficient. The survey finds that 92.32% of obese women, 84.84% of overweight women, and 81.58% of healthy weight women think that their body is not sufficient when compared to women portrayed in the media. These percentages are higher than the percentage for women that are underweight (50.0%). This supports the third hypothesis, that college-aged women who are in the overweight or obese categories are more likely to view themselves in a negative way when comparing their bodies to women portrayed in the media. It was found, however, that women of healthy weight are almost as likely to feel that their body is insufficient when compared to women in the media. According to the chi-squared test of significance, this is a statically significant relationship.

Table 3: Participant responses to the item, “I feel like my body is not sufficient when I compare myself to the way women are portrayed in the media.”

Table 4 shows the percentage of participants who have or previously had depression or a mood disorder.

Obese women in the sample are more likely to have depression or a mood disorder. Over eighty percent (84.62%) of obese females strongly agree or agree to the statement that they have had depression or a mood disorder. Overweight women have a lower percentage of participants that have had depression or a mood disorder than women who are of a healthy weight. This test is not statically significant, according to the chi-squared test of significance. Since the differences in the percentages are not large enough to be significant, the hypothesis is not supported.

Table 4: Participant responses to the item, “I have, or previously had, depression or mood disorder.”

Table 5: Participant responses to the item, “Not including family, how many close friends do you currently have?

Data in Table 5 gives the number of close friends that participants currently have. Underweight women are most likely to have five or more close friends. Obese women are the least likely to have five or more close friends. This shows a correlation that college women with high BMIs do not have as many close friendships as women with average or low BMIs. There were no prominent patterns in the data for participants with zero friends, one to two friends, or three to four friends. According to the chi-squared test of significance this test is statically significant.

Table 6 below shows the average cumulative college GPA for participants in each weight division. There is a significant pattern in the average GPA of females based on their BMI. The average GPA for students in the obese category was substantially lower than the participants in the other three weight divisions. This supports hypothesis 6 that college women with increased BMIs will have lower GPAs compared to college women with healthy BMIs.

Many factors play into performance in the classroom. This could be due to obese participants having not as many close friends, low self-esteem, or high depression rates. This data is statically significant.

In response to the statement “As a child (ages 6-12), I generally ate healthily and exercised regularly,” obese and overweight women were most likely to disagree with the statement that they had a healthy childhood. Over sixty percent (61.54%) of obese females and 27.27% of overweight females disagree or strongly disagree with the statement, while 19.74% of healthy weight females and 0% of underweight females disagree or strongly disagree. According to the chi-squared test of significance, this data is statically significant. This supports hypothesis 7 that overweight and obese women are more likely to have not exercised regularly and eaten healthily as a child. The developmental time during one’s childhood is when most people form habits that stay with them into adulthood. This is shown by the correlation between poor exercise and diet as a child and obesity as an adult.

Data was also collected on how often participants currently exercise. There is not a significant pattern in the frequency of exercise and weight division. The category, overweight women, had the highest percentage of individuals that exercised two or more times a week. All weight categories had a relatively low percentage of participants that exercised less than once a month. Even though this data is statically significant, the findings fail to support hypothesis 8 that underweight and healthy-weight women exercise more frequently than overweight and obese women. This data suggests that obese and overweight women may recognize their weight issue and are taking action to try to improve their health.

Conclusion

This study is intended to further research by exploring how BMI in college-aged women relates to social, emotional, and physical aspects of a woman’s life. The factors tested include: self-esteem, depression, close friendships, GPA, social media consumption, childhood diet and exercise, and current exercise.

This research found that a majority of women do not feel that their body is sufficient when compared to the way women are portrayed in the media. Almost all of the participants view women on media on a daily basis. Obese and overweight women are more likely to feel that they body is not up to the standards of the media than underweight women.

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Obese women do not have as many close friends and have lower GPAs than women in other weight categories. Also, obese women were less likely than women of other BMI categories to report having healthy habits as a child. Exercise frequency was not significantly different by weight category in the sample.

The main limitation for this research was that the sample was from one university. Future research could be conducted by sampling women from multiple colleges across the United States. Another limitation is that BMI does not account for total health of a person. Muscle weighs more than fat, so the BMI of some participants that exercised regularly could have put them in a BMI category that was not representative of their total health. More research could be done in this field to study the effects of obesity on young women. This data only showed correlation between variables, in order to test for causation, data would be needed over a duration of time in a more controlled experiment.

Many aspects of a person’s life are influenced by weight.

This research found that obese women are more likely to have a low social competence and low scholastic performance. Further research should be conducted to find the root of these problems. More importantly, future research should explore resources that would enable obese women to overcome emotional and physical problems.

References [1]Streeter, Veronica M,M.A.N., R.D., Milhausen, R. R., Ph.D.., & Buchholz, Andrea C,Ph.D.., R.D. (2012). “Body image, body mass index, and body composition: In young adults.” Canadian Journal of Dietetic Practice and Research, 73(2), 78-83.

[2]McLaren, L., Beck, C. A., Patten, S. B., Fick, G. H., & Adair, C. E. (2008). “The relationship between body mass index and mental health.” Social Psychiatry and Psychiatric Epidemiology, 43(1), 63-71.

[3]Posavac, H. D., Posavac, S. S., & Posavac, E. J. (1998).

“Exposure to media images of female attractiveness and concern with body weight among young women.” Sex Roles, 38(3), 187.

[4]Dijkstra, Pieternel, Dick P. Barelds, and Odette van Brummen-Girigori. (2015). “Weight-Influenced Self-Esteem, Body Comparisons and Body Satisfaction: Findings among Women from the Netherlands and Curacao.” Sex Roles, 73 (7-8), 355-369.

[5]Sand, Anne-Sofie, Nina Emaus, and Olaug Lian. “Overweight and Obesity in Young Adult Women: A Matter of Health Or Appearance? The Troms? Study: Fit Futures.”

International Journal of Qualitative Studies on Health and Well-Being, vol. 10, 2015, Social Science Premium Collection, http://ezproxy.baylor.edu/login?url=http://search. proquest.com/docview/1718812361?accountid=7014, doi:http://dx.doi.org/10.3402/qhw.v10.29026.

[6]Yeong, Jun J. “Association between Weight Control

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Failure and Suicidal Ideation in Overweight and Obese Adults: A Cross-Sectional Study.” BMC Public Health, vol. 16, 2016, SciTech Premium Collection, http://ezproxy.baylor.edu/login?url=http://search.proquest.com/ docview/1797862103?accountid=7014, doi:http://dx.doi. org/10.1186/s12889-016-2940-1.

[7]Bell, Beth. Helga Dittmar. (2011). “Does Media Type Matter? The Role of Identification in Adolescent Girls’ Media Consumption and the Impact of Different Thin-Ideal Media on Body Image.” Sex Roles. 65(478). http://link. springer.com/article/10.1007%2Fs11199-011-9964-x [8]O’Dea, Jennifer A. (2016). “Self-concept, Self-esteem and Body Weight in Adolescent Females.” Journal of Health Psychology. 11(4), 599 – 611.

[9]Monteiro, L., Novaes, J., Santos, M. (2014). “Body Dissatisfaction and Self-Esteem in Female Students Aged 9-15: the Effects of Age, Family Income, Body Mass Index Levels and Dance Practice.” Journal of Human Kinetics, 43(1), 25-32.

[10]Du, Yu. (2015). “Media Influences on Body Image Dissatisfaction: the Moderating Role of Collectivism vs.

Individualism.” Journal of Student Research, 4(2), 73-87.

Original Research

Comparing Burnout and Fitness Levels Among Medical Residents Tristin Chaudhury, Niharika Koka, and Kent Yamamoto Baylor University, Waco, Texas Abstract Medical Residency programs can induce a considerable amount of stress that negatively influences the residents well-being potentially leading to burnout. Furthermore, the purpose of this project was to find a relationship between fitness and burnout among incoming medical residents and to see if this relationship is influenced by gender. Burnout was quantified through a 22- questionnaire known as the Maslach Burnout Inventory. Physical fitness was measured through the Bruce Treadmill Test Protocol. The data was collected and analyzed graphically. The results show that neither fitness levels nor gender were in a correlated relationship with burnout.

Introduction

Residency Programs introduce new physicians who have just finished medical school to the practice of medicine under supervision. This gives these residents a great opportunity to be in a rich learning environment and to further craft their knowledge and experience in the health field.

However, these programs can induce a considerable amount of stress that negatively influences these residents well-being potentially leading to burnout. Burnout involves exhaustion of physical or emotional strength or motivation usually as a result of prolonged stress or frustration (1). Furthermore, the Waco Family Medicine Residency Program have taken steps to analyze the health and fitness of their residents.

Furthermore, they have developed a curriculum to promote the well-being of these residents.

In looking through the literature to find studies related to burnout, there were numerous articles on measured burnout among students in medical school (2).

However, little research has observed burnout in medical residents. This led to our current interest in how a medical resident may deal with the stress that often leads to burnout?

Exercise has been noted as a common coping mechanism to protect against and create resilience to stress (3). These studies showed that exercise was directly associated with a decrease in burnout levels, especially when measured immediately after a workout. According to research, exercise must be regular, structured, and a leisure-time pursuit in order to decrease burnout levels (4). Studies have shown the strenuous exercise, often at the competitive level or beyond one’s comfort level, have led to a worsened mood and increased stress after a workout (5).

The influence of gender on burnout rates was also studied, as research has shown that women tend to report higher

levels of stress in comparison to men (6).

The aim of the present study was to find the relationship between fitness and burnout among residents, and to determine if this relationship is influenced by gender.

Methods

Burnout was measured through the Maslach Burnout Inventory (or labeled as MBI). This is a 22 questionnaire that allows one to quantify burnout. In addition, this specific survey is validated and used in occupational settings.

Before measuring burnout, a clear definition of burnout was provided. It primarily emphasizes three categories of burnout. The most significant one is emotional exhaustion: this directly pertains to a person’s perceived psychological level. These are feelings of being emotionally overextended and exhausted by one’s work. Depersonalization is when one has a dehumanized perception of others. A physician may start to view his patients as biological parts working together instead of as human beings, and this may lead to the development of an insensitive attitude towards the patients. And the last category is affected by both emotional exhaustion and depersonalization and it’s a person’s sense of accomplishment at work at the end of the day. A burned out individual may feel unhappy about himself and dissatisfied with his success at his workplace.

These are three components that make up burnout. Each of these components address different questions on the Maslach Burnout Inventory. There are 9 questions that address Emotional Exhaustion. There are 5 questions that address Depersonalization. Also, there are 8 questions addressing Personal Achievement. The questions on the Inventory were scaled to quantify each of the components.

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The sum scores for each category were interpreted with

this table involving the three components of burnout.

The scale was ranged from 0 to 6. 0 represented never to express certain feelings. 6 represented expressing feelings every day. For example, a high score of Emotional Exhaustion was equal to or greater than 27.

Table 1: Scores for emotional exhaustion, depersonalization, and personal accomplishment.

The physical fitness levels of the residents were quantified through their VO2 Max levels. VO2 Max is the maximum amount of oxygen that an individual can utilize during intense or maximal exercise. It is measure as milliliters of oxygen used per minute per kilogram of body weight (ml/ (min*kg)). This specific project utilized the Bruce Treadmill Test Protocol to estimate the VO2 Max of the medical residents. In the Bruce protocol, the treadmill speed and incline is increased every three minutes.

In reviewing how the data was collected, the cohort of 21 individuals (10 male/ 11 female) were tested through the Bruce Protocol and the Maslach Burnout Inventory.

The cohort was mixed and then split into two groups.

Each group participated in a particular test. The Maslach Burnout Inventory was orally administered by physicians privately. Burnout was quantified through the use of this data. The Bruce Treadmill Test Protocol was performed by the other group. These individuals exercised on the treadmill wearing a mask that measured their VO2 max while being monitored by a research assistant. After data in each test was gathered, the cohorts switched and performed the other required test. Furthermore, this one day of testing was sufficient to gather the data that was needed of the cohort to quantify their VO2 max levels (fitness) and burnout.

Before looking at question 1 and analyzing the data, the Burnout Ranges and VO2 Max Ranges were identified.

Medical residents were partitioned into validated categories of low, moderate, or high levels of burnout and VO2 max based upon their sum scores.

It is important to understand the cut off points. For example, high levels of fitness are VO2 Max scores equal to or greater than 45.5 ml. This chart represents the important cutoff points and how these people were categorized.

It is important to note the cohort that was tested.

The chart provided gives the mean of different components of the incoming first-year medical residents. For example, the average age of the cohort was around 28 years of age. Another specific example, the average VO2 Max was recorded at around 39 ml/(min*kg). Furthermore, this chart provides a generalization of scores and data most commonly seen in the project, as well as the range of the data.

Results:

The same conclusions of each burnout component (EE, DP, and PA) in relation to physical fitness can be drawn from each category based on the results shown in the graphs. If one analyzes the graphs, the standard error bars have a broad range in both genders in each category.

Furthermore, there was consistent overlap of these error bards leading to the conclusion that there is no significant difference of burnout scores among genders.

Graph 1: The graph shows y-axis (Emotional Exhaustion scores) vs. x-axis (Levels of Fitness or VO2 Max levels). One can see the consistent overlap of the error bars shows no significant difference or relationship between Emotional Exhaustion scores and levels of fitness.

Table 2: VO2 max ranges on high, moderate, and low levels.

There were three sub question that needed to be answered in order to determine a relationship between burnout and physical fitness. 1). How varied is the cohortâ&#x20AC;&#x2122;s demographics? 2). Does Fitness impact burnout scores per category (EE, DP, PA)? 3). Does gender influence burnout scores per category (EE, DP, PA)?

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In analyzing the graphs and the data gathered, there is a decrease in emotional exhaustion, a decrease in depersonalization, and an increase in personal accomplishment with increased VO2 Max levels. Thus, there is an inverse relationship between VO2 max and emotional exhaustion and between VO2 max and depersonalization. There is a direct relationship between VO2 max and emotional exhaustion and between VO2 max and depersonalization.

Graph 2: y-axis (Depersonalization scores) vs. the x-axis (Levels of Fitness or VO2 Max levels). One can see the consistent overlap of the error bars shows no significant difference or relationship between depersonalization scores and levels of fitness.

Discussion

The cohort measured (10 men/11 women) is young, healthy, and exhibit low EE, DP, and high PA. Neither fitness levels nor gender impacted how the incoming residents responded to the Maslach Burnout Inventory.

Why? One of the limitations was the small sample size. Even though there was a variety within the sample, it clearly needed to be larger. Another factor to this conclusion is the fact that the sample measured consists of recent medical school graduates. Graduation comes with a sense of accomplishment and personal achievement, contributing to the high PA scores. In addition, they had the entire summer off, giving them time to relax and accounting for the generally low EE and DP scores.

Continued research should be done over the years to account for more subjects and variability in scores over the years as the difficulties of medical reidency comes into play.

Perhaps with more information, fitness levels or gender will more directly influence burnout levels.

For future application, a project could analyze the change in burnout of these medical residents over the beginning and end of their residency program. Another interesting experiment would be to apply this project to Baylor undergraduate students and measure their change in burnout and fitness levels over their four-year track.

Ackowldegements Dr. Wilson, a doctor of Internal Medicine; Crashanta Evans, a Preceptor; incoming residents at the Waco Family Health Center; Dr. Pete Grand jean and Dr. Burritt Hess, a Co-Investigators of Physician Well-Being Study.

Graph 3: y-axis (Personal Achievement scores) vs. the x-axis (Levels of Fitness or VO2 Max levels). One can see the consistent overlap of the error bars shows no significant difference or relationship between personal achievement scores and levels of fitness.

Graph 4: y-axis (burnout scores) vs. x-axis (each of three burnout domains).

References [1]Burnout https://www.merriam-webster.com/dictionary/ burnout (accessed Jun 11, 2017).

[2]University of Virginia School of Medicine https://med.virginia.edu/exercise-physiology-core-laboratory/fitness-assessment-for-community-members-2/vo2-max-testing/ (accessed June 6, 2017).

[3]Mental Health and Depersonalization Disorder https:// www.webmd.com/mental-health/depersonalization-disorder-mental-health (accessed Jun 6, 2017).

[4]Vries, J. de. Exercise as intervention to reduce stress http:// publication-online.com/files/8615/0280/0421/14739_JdeVries_ ONL.pdf (accessed Jun 9, 2017).

[5]http://www.cleveland.com/healthfit/index.ssf/2012/12/ too_much_exercise_could_be_bad.html [6]http://www.apa.org/news/press/releases/stress/2010/gender-stress.aspx (accessed Jun 7, 2017).

[7]A Study on the Coffee Spilling Phenomena in the Low Impulse Regime https://www.sciencedirect.com/science/article/ pii/S2078152015300377 (accessed Jun 8, 2017).

[8]VO2 max https://en.wikipedia.org/wiki/VO2_max (accessed Jun 8, 2017).

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Abstracts

Long Term Trends in Atmospheric Particulate Matter in Central Texas Jessica Su; Mentor: Rebecca Sheesley, Ph.D. Baylor University

Atmospheric particulate matter (PM) is comprised of different sized airborne particles that can be harmful to both the environment and humans. The Environmental Protection Agency (EPA) has set National Ambient Air Quality Standards (NAAQS) for particles 2.5 and 10 micrometers or smaller (PM2.5 and PM10, respectively) because these particles are respirable and cause the most damage to human health [1]. Because a large portion of PM is carbonaceous, the composition of PM can be further categorized into two groups: organic carbon (OC) and elemental carbon (EC).

Long term monitoring of OC and EC has been conducted in Riesel, TX, a 73 rural town of 1,000 people 12 miles east from Waco, TX. Between 2011 to 2016, a total of 202 PM2.5 samples have been collected at the United States Department of Agriculture-Agricultural Research Service site (USDA-ARS). These samples, collected every six days (EPA schedule), were analyzed by the NIOSH 5040 method using a thermal optic transmission carbon analyzer from Sunset Laboratories to determine ambient OC and EC concentrations [2]. This five year dataset was then used to characterize long term seasonal and monthly trends at this background site. To better understand the interaction between gas and particle phase pollutants, correlation analyses’ were completed using ozone data from a local Texas Commission on Environmental Quality (TCEQ) [3]. This site represents the only regional background site for carbonaceous PM in central Texas and helps to understand potential impacts of PM on regional climate and human health.

Prevention of Death by Suicide in OEF/OIF Veterans Kensi Boenker Baylor University

Rates of death by suicide have steadily risen among veterans returning from Operation Enduring Freedom (OEF) and Operation Iraqi Freedom (OIF). It has been estimated that an average of 20 veterans die by suicide every day. Current estimates greatly contrast from previous historical trends that have shown a decrease in suicide during times of war, which highlights the unique differences between OEF/OIF veterans and aging veterans from past wars. The Interpersonal Theory of Suicide (IPTS) has shown to be an important tool in the assessment of potential risk of suicide, which considers the role of three major components (“perceived burdensomeness,” “thwarted belongingness,” and “acquired capability” (Joiner, 2005)). In addition to using the IPTS as a source for assessing suicide risk, prevention should be emphasized throughout the veterans’ most vulnerable times at the beginning of deployment and through the transition process by implementing programs that provide social support for the veteran. This poster reviews recent research concerning suicidal ideation and suicide risk with the purpose of analyzing modern military culture, testing the effectiveness of assessing potential risk of suicide through measures derived from the IPTS, and utilizing effective programs of social support to decrease the likelihood of death by suicide.

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Abstracts

Alveolar Epithelial Cell Ligands as Therapy for for Pneumocystis Pneumonia Ariane Kubena Baylor University

Pneumocystis (PC) is an opportunistic fungus that causes a limited asymptomatic infection in immunocompetent individuals but results in Pneumocystis Pneumonia (PCP) in subjects with impaired CD4+ T cell immunity. While detectable anti-PC antibody is commonly found in most humans by 2 years of age, approximately 400,000 cases of PCP occur yearly worldwide. PCP is the most frequent HIV-associated opportunistic infection, showing a 10-20% mortality rate for those with HIV/AIDS and a 30-50% mortality rate for those with cancer or other immune deficiencies. The mortality rate for those placed on a ventilator due to the side effects of PCP is 50% or even higher. The absence of CD4+ T cells during PCP is accompanied by the recruitment of CD8+ T cells to the lung, which are ineffective for host defense against PC and cause inflammatory lung injury. Our laboratory recently determined that a high proportion of CD8+ T cells in the lungs during PCP express the inhibitory receptors PD-1 (programmed cell death protein 1) and Lag-3 (lymphocyte-activation gene 3). These receptors suppress CD8+ T cell effector function and may impair CD8 antifungal activity and/or limit immunopathogenesis during PCP. Because the tight attachment of PC to alveolar epithelial cells has been shown to activate the NF-κB pathway, we hypothesized that alveolar epithelial cells produce inhibitory ligands that contribute to the suppression of CD8+ T cells during PCP. To test our hypothesis, type II alveolar epithelial cell lines were stimulated in vitro with Pneumocystis, and PD-L1, PD-L2, and galectin-3 production was measured at the mRNA and protein level.

Our study suggests that alveolar epithelial cells secrete PD-L1, PD-L2, and Gal-3, suggesting that alveolar epithelial cells may contribute to CD8+ T cell suppression during PCP by stimulating the inhibitory receptors PD-1 and Lag-3. Modulating inhibitory receptor pathways may represent a potential adjunctive therapy to reduce lung injury and enhance fungal clearance in PCP patients.

Third Grade Students’ Perceptions and Attitudes Towards Science Mehul Mistry; Mentor: Marty Harvill, Ph.D. Baylor University - VA CERP

This study attempts to find the perception and attitudes towards science held by 3rd grade students at China Spring Elementary School in Waco, TX. In order to measure these qualitative traits, 182 students were given a survey prior to a fieldtrip to the Lake Waco Wetland, and at conclusion of the Lake Waco Wetlands fieldtrip. The survey aimed to measure: (a) The draw a student feels towards the sciences, (b) The understanding what it means to be a scientist (c) An assessment of the students’ knowledge of scientific topics covered either in the classroom or during modules covered during their fieldtrip to the wetlands. In effort to account for students “guessing” answers on the pre-assessment portion of the survey, half of the surveys possessed an option for “I do not know.” The data indicates that after the fieldtrip students had a better outlook and attitude towards the sciences. Also, the students who had the option for “I do not know” showed improvement in the post assessment questions regarding scientific topics covered during the module learning experiences.

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Review Articles

Neuropharmacology of alpha7 nicotinic acetylcholine receptor in Alzheimer’s Disease Courtney Smith Baylor University Abstract

Alzheimer’s disease (AD) is the leading cause of dementia and involves the development of amyloid beta plaques.

Through its interactions with amyloid beta plaques, the alpha7 nicotinic acetylcholine receptor (α7) mediates the effects of the plaques as they develop within the brain. Review of research in this area shows that the exact nature of the relationship between amyloid beta plaques and the α7 receptor is unclear but may have clinical implications in future therapeutic treatment for AD. Amyloid beta is present in both healthy individuals and those with AD, though the effect of α7 receptors in the presence of the amyloid beta protein is different between the two conditions. Variation in the concentration and size of the amyloid beta proteins can modulate the function and concentration of the α7 receptors to develop plaques and contribute to the development of AD. In addition, inflammation and respiration illnesses can impact α7 receptors and their interaction with beta amyloid plaques thereby increasing the likelihood of developing AD. This integration of α7 receptors in the development of AD drives research into treatments utilizing the α7 receptors to mitigate their effects in developing amyloid beta plaques. Despite promising results in rodent studies with these treatments, these effects have not translated to humans successfully, requiring future research to improve the therapeutic effects in AD patients.

Introduction

Worldwide, Alzheimer’s disease (AD) is the

leading cause of dementia and was the seventh leading cause of death in 2004 (Conejero-Goldberg, Davies, & Ulloa, 2008, pg. 694). By 2050, the disease is expected to impact approximately 106 million people (Dziewczapolski, Glogowski, Masliah, & Heinemann, 2009, p. 8805).

It is a neurodegenerative disease hallmarked by cognitive impairments across a wide range of functions beginning with episodic memory declines then progressing to aphasia, apraxia, agnosia, and impaired executive functions accompanied by neurofibrillary tangles and amyloid plaques that are the results of hyperphosphorylated tau protein and misfolded amyloid beta protein (Aβ), respectively (Conejero-Goldberg et al., 2008, pg. 694).

Tau is a protein that stabilizes microtubules and aids in the transportation of vesicles along neurites. The binding between tau and the microtubule is regulated by phosphorylation, however, hyperphosphorylation of tau causes it to dissociate from the microtubule and accumulate in paired helical filaments (PHFs) that in turn accumulate into clusters within the cell bodies forming neurofibrillary tangles (NFTs). The dissociation of tau from the microtubules is associated to the loss of synapses and degeneration of neurons as axonal transport is limited without tau. Because of the involvement of

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abnormal tau aggregation in the brain, AD is referred to as a tauopathy (Conejero-Goldberg et al., 2008, pg. 694).

Aβ comes from abnormal proteolysis of the transmembrane amyloid beta precursor protein (APP) by β and γ secretases. These pieces of Aβ protein then fold into extracellular senile plaques. These plaques do not inherently cause AD, as they are present even in healthy, normal individuals (Conejero-Goldberg et al., 2008). In fact, the proper cleavage of APP and subsequent folding into Aβ proteins does not lead to AD, as long as the production and elimination of the Aβ plaques is kept in balance by degradative enzymes.

Healthy Aβ may even serve important physiological roles and impair neuronal death. It has been indicated to regulate ion channel expression, excitability of neurons, formation of memories, and plasticity of synapses (Sadigh-Eteghad et al., 2014).

In addition, physiological levels of Aβ are able to activate α7 thereby enhancing the induction of hippocampal long-term potentiation (LTP). When Aβ levels increase, they inhibit LTP induction by increasing extra-synaptic NDMA receptors that result in detrimental ERK/MAPK activation (Pirttimaki et al., 2013). The Aβ protein associated with AD is normally found in two different lengths, based on how long a segment of the APP protein is cut off—AB1-40 and AB1-42, which are 40 and 42 amino acids in length respectively (Nery

et al., 2013). When Aβ accumulates, it begins with small molecules. Low molecular weight fractions of Aβ (monomers, dimers, and trimers) form first then are followed by oligomers or insoluble fibrils. The lower weight forms of Aβ are usually non-pathogenic with Aβ monomers operating protectively on developed neurons to prevent excitotoxic death and improve endurance. The larger weight oligomers and insoluble fibrils are the molecules that break apart and trigger cytotoxicity in cells (Sadigh-Eteghad et al., 2014).

Nicotinic acetylcholine receptors (nAChR) are ligand gated cation channels that are found throughout the central and peripheral nervous systems, in addition to neuromuscular junctions, and are activated by the neurotransmitter acetylcholine. When activated, ion influx through the nAChR channels excites the neuron. As a class, these receptors are linked to learning and memory (Fan, Gu, & Wei, 2015, pg. 354). In the CNS ACh is connected with synaptic plasticity and stability. In the CA1, neocortex, dentate gyrus, and piriform cortex it increases the amplitude of the synaptic potential following LTP and it decreases the conductance of currents dependent on voltage and Ca2+. The impact of α7 on learning and memory is evidenced in CHRNA7 (an α7 gene) knock out mice that exhibit dysfunction in attention and working memory.

In schizophrenics there are variations in CHRNA7 that influence attention gating (Conejero-Goldberg et al., 2008).

Further studies with KO mice showed a deficit in implied prolonged sessions in memory tests, reinforcing the idea that nAChR are involved in LT memory. Through binding studies using [3H]-nicotine and [3H]-ACh, Lombardo et al. found a reduction of nAChR, muscarinic acetylcholine receptors (mAChr), and choline acetyltransferase (ChAT) in AD, indicating a relationship between the disease progression and structure of the ACh system (Lombardo & Maskos, 2015).

The alpha7 nicotinic acetylcholine receptor (α7) is a homopentameric ionotropic receptor made up of five α7 subunits that is reported to desensitize quickly when continuously exposed to agonists (Fan et al., 2015). It is primarily permeable to Na+ but has a high conductance for Ca2+. Therefore the receptor is considered to have metabotropic-like properties by activating the Ca2+ secondary messenger system. It has low sensitivity for ACh contrasted by a high affinity for the α7 antagonist α-bungarotoxin. Its mechanism involves alternative signal pathways in neuronal and non-neuronal cells. In neurons, α7 increases intracellular Ca2+ through voltage-activated channels, activating ERK1/2 in a Ca2+ and PKA dependent manner.

In non-neurons such as astrocytes, α7 influences Ca2+ release from intracellular storage (Bitner et al., 2010; Conejero-Goldberg et al., 2008).

Aβ Effects on α7 Nicotinic Acetylcholine Receptors

Both the positive and negative effects of Aβ are

linked to α7. When Aβ is monomeric and in low concentrations (pΜ) it is neuroprotective via α7. Increasing concentrations of Aβ, especially in oligomeric form, cause reductions in LTP in a concentration-dependent manner (Sadigh-Eteghad et al., 2014). Aβ can complex with α7 and enter the cell via endocytosis, triggering the cell to also absorb in NMDA receptors via endocytosis (Dziewczapolski et al., 2009). Thus, the relationship between Aβ and α7 seems to be dependent upon the type of Aβ present as well as how much is present, but further research is necessary to clarify the exact nature of this relationship. Some headway at least into understanding the chemical nature of the interaction between α7 and Aβ came with amino acids 12-18 of the Aβ sequence being identified as the segment that binds with α7 (Lombardo & Maskos, 2015).

Liu, Xie, Emadi, Sierks, and Wu in 2015 studied whether α7 is necessary for the cytotoxic effects of Aβ plaques or not, particularly at nanomolar concentrations.

Previous research showed that Aβ has a high affinity for α7 and that by linking to it, it disrupts normal α7 function. Liu et al. state that when Aβ is chronically present there is an upregulation in α7 receptors on neurons and glia cells that increase neuronal hyperexcitability which may contribute to the neurotoxicity of Aβ by increasing presynaptic glutamate release. They found that inhibiting α7 with methyllycaconitine (MLA) or deleting the α7 gene decreased the cytotoxicity resulting from chronic Aβ exposure. The chronic larger aggregates of Aβ increased the expression of α7 on the cell surface, but did not significantly alter the overall α7 expression level. This indicates that Aβ aggregates in some way influence the intracellular transit or assembly of α7 surface proteins. By upregulating the α7 surface receptors, there is an increase in the Ca2+ concentration in the cell leading to cytotoxicity. In addition to increasing the Ca2+ concentration, once Aβ binds with α7 it forms a complex that enters the cell via endocytosis and accumulates within the lysosome compartment, resulting in further cytotoxicity (Liu, Xie, Emadi, Sierks, & Wu, 2015).

While Liu et al. argue for the upregulation of α7 receptors, Conejero-Goldberg and colleagues gave evidence for downregulation of α7. Decreases in nAChRs, especially α7 in the frontal lobe, are associated with the process of aging but also with AD and the subsequent loss of cognition.

In AD, the α7 in the cortex and hippocampus is reduced.

In the hippocampus, there was found a 36% reduction in α7 proteins but a 65% increase in mRNA expression that indicates that these cells are trying to compensate through transcription for a physical loss or blocking of the receptors (Conejero-Goldberg et al., 2008).

The discrepancy between these two studies concerning the effects of Aβ on α7 concentration may be due to the phenomena mentioned by Lilja, Porras, Storelli, Nordberg, and Marutle in 2011. They reported that α7 was upregulated on astrocytes, but downregulated on neurons

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in AD. This is one direction for future research. Discerning the effects of different Aβ on α7 in different brain locations is important for determining the effects of various treatments.

Using the α7 agonists varenicline and JN403, they studied the effects of different forms of Aβ on α7 receptors. Their findings indicated that nanomolar concentrations of fibrillar AB1-40 is neurotoxic while physiologically normal concentrations of both fibrillar and oligomeric AB1-40 and AB1-42 did not significantly affect cell viability. Both varenicline and JN403 protected cells exposed to fibrillar AB1-40 suggesting that neuroprotective functions are at least partly moderated through α7. This protective mechanism may be due to the agonists displacing Aβ from α7, similar to the effects of α7 agonist S24795 shown in two other studies. Oligomeric AB1-40 also modulated the affinity of varenicline to bind and displace the nicotinic receptor radioligand, [3H]epibatidine, which indicates that oligomeric Aβ may be an allosteric modulator of nAChR (Lilja, Porras, Storelli, Nordberg, & Marutle, 2011).

Pirttimaki et al. studied the effects of Aβ on astrocytic α7 receptors. Astrocytes regulate synapses through the release of gliotransmitters (ATP, D-serine, and glutamate) when intracellular levels of Ca2+ increase.

When Aβ is present, it increases α7-dependent activity in CA1. In this study MLA inhibited the effect of Aβ, much like in the study by Liu et al., and the α7 selective positive allosteric modulator (PAM) PNU120596 enhanced the response of astrocytes to Aβ, while antagonists to other nAChR subunits did not inhibit the Ca2+ increase caused

by Aβ. All of this indicates that Aβ functions through α7.

In addition to MLA, NMDA receptor antagonist D-APV blocked the Aβ effect by inhibiting the glutamate release from astrocytes, indicating that Aβ induces glutamate release through α7 (Pirttimaki et al., 2013).

Along with Ca2+ concentrations, the study looked at changes in NMDAR-mediated slow inward currents (SICs) as indicators of astrocytic glutamate release. In the Tg2576 AD model mice these SICs were increased compared to WT mice. When these cells were stimulated with the α7 agonist PNU282987, there was an increase in the SIC frequency for WT mice, but mixed results in the AD model mice, indicating dysregulation of the Ca2+-gliotransmitter release pathways. This difference in the SICs of the Tg2576 mice contributed to the increased CA1 activity from Aβ by enhancing the impact of NMDA-mediated currents. The implications of this study lie in early detection of AD development. These changes in gliotransmitters released from astrocytes were observed in young mice (3-4 months old) that exhibited no synaptic or cognitive deficits. Thus, a potential future method of AD detection would involve monitoring early astrocyte Ca2+ concentrations and gliotransmitter release

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prior to the development of any AD impairments (Pirttimaki et al., 2013).

Dziewczapolski, Glogowski, Masliah, and Heinemann studied the impact of α7, APP, and Aβ on the development of AD. They found that in APP mice there was a decrease in the synapse terminal marker synaptophysin in both the frontal cortex and the hippocampus whereas in APPa7KO mice this decrease was not observed. As they aged, the APP mice began to have early phase LTP deficits in the Schaffer collateral-CA1 synapse and could not maintain LTP in the late phase. APPa7KO mice lacked any of these deficits, despite having extracellular Aβ levels comparable to APP mice, therefore indicating α7’s involvement in the effect of Aβ on the neuronal function. It also indicates that intracellular Aβ has a greater detrimental effect in neurons than extracellular deposits of Aβ. Further research is necessary to determine if the effect of a7KO is truly due to the lack of α7 or, because the Aβ couldn’t complex with α7 and enter the cell, the NMDA receptors were protected from Aβ-induced endocytosis (Dziewczapolski et al., 2009).

α7 mediates the cytotoxicity of AB1-42 as when AB1-42 binds α7 it induces tau phosphorylation via ERK and c-Jun and N-terminal kinase (JNK-1). In contrast, α7 agonists block apoptosis by activating tyrosine kinase Janus 2 (JAK2) and phosphorylating Akt through phosphatidylinositol-3-kinase (PI3K) thereby influencing α7’s neuroprotective abilities. This pathway is inhibited by the α7 antagonist a-bungarotoxin and utilized by the α7 agonist TC-1698, evidence that it functions via α7 (Conejero-Goldberg et al., 2008).

Inflammation and antibody effects on AD progression via α7 Nicotinic Acetylcholine Receptors

Based on the findings that former smokers a reduced risk for AD and Parkinson’s disease (PD) as they have fewer amyloid plaques than non-smokers and that nicotine treatment in general has shown improvements in attention but not memory, studies are looking into the effects of nicotine on neurons and how it may be preventative. This indicates a possible role of inflammation in AD and PD. In both diseases and general aging, there are local inflammatory responses that are maintained by activated microglial cells. Normally, microglia are neuroprotective, secreting growth factor or anti-inflammatory mediators to maintain tissue homeostasis. But these cells can become neurotoxic when stimulated by lipopolysaccharides (LPS) found in gram-negative bacteria walls and they then begin secreting free radicals and inflammatory cytokines (such as TNF). The immune responses initiated by microglia cells are moderated in part by α7 receptors. Nicotine can trigger anti-inflammatory pathways to combat this reaction by decreasing the production of tumor necrosis factor (TNF) through blocking the NF-kB pathway via α7 thereby reduc-

ing the activation of ERK and p38 MAPK (Conejero-Goldberg et al., 2008).

The importance of inflammation in the course of AD is additionally evidenced in the effect of antibodies against α7. The ability of antibodies to penetrate into the brain is increased with inflammatory stimuli. Therefore, the greater the inflammation, the more nAChR antibodies are able to enter into the brain and affect the receptors within. When antibodies for nAChR are present in the brain, there is an associated decrease in the number of nAChRs. The presence of α7 antibodies has been linked to negative impacts on episodic memory. Losing α7 receptors has also been shown to increase Aβ oligomer accumulation. Together, these impact the worsening of memory seen in AD (Lykhmus et al., 2011).

Koval et al. in 2011 also approached the issue of inflammation and antibodies impacting α7 function and contributing to AD pathology. The downregulation of α7 is not always associated with impaired protein synthesis or endocytosis of the regulators upon forming a complex with Aβ; therefore some are impacted via a different route.

Koval et al. hypothesized that autoantibodies may contribute to the decreased levels of α7 found in AD. Autoantibodies to AB1-42 have been found in parallel with AB1-42 depositions in the brains of AD patients and autoantibodies to α –synuclein have been found in PD patients, therefore there is a precedent for autoantibodies to be associated with cognitive disorders. The origin of autoantibodies is still unclear, , they may come from dysfunctional immune cells not caught during differentiation, they may be genetically inherited, or they may be triggered when an infection triggers the formation of antigens that cross-react with self-proteins. For some time, the CNS was thought to be safe from these autoantibodies due to the blood brain barrier (BBB) however, increasing evidence has found NMDA and glutamate type 3 receptor antibodies in the brain triggering the search for other autoantibodies present in the CNS (Koval et al., 2011).

Studies have shown that in mice immunized with a4 or α7 extracellular domains or rabbit antibodies against α7(1-208) there was a decrease in nAChR densities in the spleen and in the brain if the injections were coupled with an inflammatory stimulus. This is significant as antibodies against a4 and α7 are normally present in healthy individual’s blood, however, when there is inflammation, the antibodies are able to cross into the brain, as correlated by Lykhmus et al. The increasing permeability of the BBB associated with aging or inflammatory diseases may contribute to the development of AD pathology and the ensuing cognitive decline (Koval et al., 2011).

Koval et al. expanded their explanation to include further risks that increase a4/α7 nAChR specific antibodies. A major factor is the number, severity, and spectrum of respiratory diseases an individual may experience in their lifetime. Respiratory infections that result in the

destruction of respiratory epithelium, such as chronic obstructive bronchitis (OB) and chronic obstructive pulmonary disease (COPD), may stimulate immune responses that generate α7 autoantibodies. In AD patients that had high levels of α7 autoantibodies, there was an increase in the number of α7 receptors on blood lymphocytes and in early onset AD patients there was an increase in the antibodies levels and a greater frequency of antibodies present.

In α7(1-208) immunized mice, worsening episodic memory was associated with an increase in antibodies penetrating the brain and decreasing the number of α7 receptors (Koval et al., 2011).

Potential Treatments Utilizing α7 Nicotinic Acetylcholine Receptors

Galantamine, a weak acetylcholinesterase inhibitor, is a current treatment for AD and functions primarily as an allosterically potentiating ligand of nAChR. It has been found to be neuroprotective against toxicity from glutamate, tropic factor deprivation, hypoxia, and β-amyloid via nAChR. It also serves a neurogenesis function through increasing the phosphorylation of the nerve growth factor (NGF) receptor trkA and the BDNF receptor trkB in mouse hippocampus. 192IgG-saporin, a cholinergic immunotoxin, decreases hippocampal levels of proBDNF and galantamine reverses this effect. Galantamine increases insulin-like growth factor 2 (IGF2) mRNA in the hippocampus, an effect blocked by MLA. IGF2 is involved in inhibitory avoidance learning in the hippocampus by promoting IGF2 receptor dependent persistent LTP in the hippocampus. Galantamine enhances cognitive function partly by increasing the levels of BDNF, NGF, and IGF2 as these are some of many factors that generate adult neurogenesis in the hippocampus. Beyond the neurogenesis properties of it, galantamine also increases the phosphorylation of CREB in the hippocampus, increasing synaptic plasticity (Kita et al., 2013).

Nery et al. found that soluble Aβ binds to α7 with nanomolar affinity to the heptapeptide with the amino acid sequence, IQTTWSR (IQ), that is homologous to a sequence found both in nicotine and in many human nAChR binding pockets. Nanomolar concentrations of IQ were able to inhibit Aβ inhibition of cells expressing α7 suggesting the action of Aβ at nAChRs is mediated through the nicotine/ACh binding site in the receptor. They posit that differences in effects of drugs and Aβ on cells with α7 versus cells that have other nAChRs is due to the homopentameric nature of α7. α7 receptors have 5 identical ligand-binding sites that are all able to be affected by the same materials while other heteropentameric receptors may have only 2-3 binding sites each that bind the same ligands. Further research into the efficacy of IQ and analogues may offer potential new methods of Aβ blockage on nAChR cells (Nery et al., 2013).

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Fan et al. in 2015 argued that α7 agonists might be a useful treatment for AD as it could outcompete Aβ for binding α7 thereby reducing Aβ induced apoptosis and supplementing the decreased ACh in AD. They summarize the usages of various agonists, both full and partial, for α7 receptors in the treatment of AD. These include descriptions on ABT-107, S24795, and A-582941.

ABT-107 is highly selective for α7 with reduced or no activation for the other nAChR subtypes which may make it useful for humans. S24795 is a partial α7 agonist has no affinity for the other alpha nAChR subunits or muscular nAChR but it reduces the formation of Aβ-α7 complexes both in vivo and in vitro while releasing Aβ that has already bound with α7. A-582941 is another partial agonist for α7 that has a high affinity for the receptor and has shown good brain penetration in animal studies along with improved cognition (Fan et al., 2015).

Bitner et al. in 2010 conducted research utilizing 5-)6-[(3R)-1-azabicyclo[2.2.2]oct-3-yloxylpyridazin-3yl)-1H-indole (ABT-107) and 2-methyl-5-(6-phenyl-pyridazin-3-yl)-octahydro-pyrrolo[3,4-c]pyrrole (A-582941).

A-582941 was found to enhance signaling pathways that influence synaptic plasticity, especially extracellular signal-regulated kinase (ERK) and cAMP response element-binding protein (CREB) phosphorylation. Akin to A-582941, ABT-107 caused increased phosphorylation in both ERK1/2 and CREB. The ERK pathway aids in the regulation of cell functions such as growth, differentiation, survival, and synaptic plasticity. CREB operates as an effector-substrate of the ERK pathway instigating the expression of genes for synaptic plasticity proteins including brain derived neurotrophic factor (BDNF). In AD patients, there is reduced BDNF and phosphorylated CREB (Bitner et al., 2010).

Both ABT-107 and A-582941 also increased the phosphorylation of the inhibitory regulatory amino acid residue Ser9 on glycogen synthase kinase-3 (GSK3β), which is associated with the hyperphosphorylation of tau, thereby inhibiting its action in both the cortex and hippocampus of normal and AD mice but not in a7KO mice. Acute administrations of ABT-107 increased the phosphorylation of the inhibitory Ser9 residue in GSK3β while also decreasing the amount of phosphorylated tau protein in the hippocampus of mice. (Bitner et al., 2010).

ABT-107 efficacy was not affected when co-administered with donepezil, indicating that ABT-107 could be used with acetylcholinesterase inhibitors (AChEIs). It also lacked the psychomotor stimulant properties and the abuse potential of nicotine, however, more research in self-administration is necessary to confirm the lack of abuse potential.

In tests on monkeys and mice, it improved both short term (ST) and working memory especially after a long delay period. The effects of ABT-107 continued even after it left the receptor indicating that it may trigger sec-

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ondary pathways that impact synaptic plasticity. The effects of both ABT-107 and A-582941 indicate the potential use of α7 agonist in inhibiting GSK3β by phosphorylating the Ser9 residue via the phophoinositide-3-kinase/Akt pathway and thereby reducing the amount of tau phosphorylated.

When nicotine exerts a neuroprotective effect it also initiates the phophoinositide-3-kinase/Akt pathway (Bitner et al., 2010).

Another method under investigation for potential AD treatment usage is positive allosteric modulators (PAMs). PAMs have several advantages over using α7 agonists. When using PAMs, the α7 activation only occurs in the presence of the endogenous agonist and thereby there is less risk of desensitization from chronic administration of an exogenous agonist. PAMs also work well for smokers as they are not competing with the nicotine for the active site (Nikiforuk, Kos, Potasiewicz, & Popik, 2015).

There are two main categories of PAMs. Type I PAMs potentiate the agonist-induced peak current but do not affect the desensitization process of the neuron. Type II PAMs delay the desensitization kinetics. A study has shown that type I and type II PAMs and galantamine, an allosteric modulator, postponed delay-induced impairment on the novel object recognition task (NORT) in rodents and improved results on the attentional set-shifting task (ASST) but these effects were hindered by MLA. The type II PAM, N-(5-Cholor-2,4-dimethoxyphenyl)-N’-(5-methyl-3-isoxazolyl)urea (PNU-120596), with sub-threshold dose of donepezil improved recognition memory but the effect was blocked by MLA, indicating the α7 receptor mediated the procognitive effects. With repeated administration, the type I PAM, N-(4-cholorophenyl)-[[(4-cholorphenyl)amino]methylene]-3-methyl-5-isoxazoleacet-amide (CCMI), enhanced memory in rats. Acute administration of the type I PAM, NS1738, had social recognition enhancement affects similar to nicotine. These studies conducted by Nikiforuk and colleagues give evidence that both types of PAM are able to enhance short-term recognition memory and substantiate other studies’ results showing that galantamine is able to enhance longer-interval memory retention in mice (Nikiforuk et al., 2015).

Difficulties in α7 Nicotinic Acetylcholine Studies

Despite multiple successes in improving memory and cognition in lab animals, there are issues in transferring these successes to human patients.

Lewis, Schalkwyk, and Bloch (2017) address the issue of poor translational quality between rodent and human studies. Despite wide success for many α7 agonists in rodent experiments in improving spatial and non-spatial memory, the meta-analysis conducted by Lewis et al. found that in human subjects there was no significant benefit from α7 over the placebo in improving the overall cognition of the patient. They suggested that the reason for this disparity may be the rapid desensitization of α7 receptors

in the continued presence of an agonist, thereby diminishing the effect after repeated dosages. In addition, many agonists for α7 also have an impact at other receptors including other nAChR subtypes or 5-HT3. The review suggested multiple additional issues in transitioning from rodents to humans. First, most rodent studies use acute treatment of the drugs rather than the chronic regime found in human treatments, thus there is no opportunity for desensitization to develop in the rodents. Some of these drugs have also had some success in earlier human phase studies but have issues that surface in later phase trials. Thus, suggestions for improvements in translation from rodent studies to human testing are to: 1) initiate more experiments looking at chronic α7 agonist exposure in rodents, 2) then having humans complete cognition tests under chronic dosage and then, 3) only when improvement is seen in both spatial and non-spatial tasks may the drug then progress forward into the next clinical phase (Lewis, van Schalkwyk, & Bloch, 2017).

There is additional difficulty in experiments determining if positive effects of α7 agonists in treating AD are due to its effects on the α7 receptor or through the rapid desensitization of the receptor. In addition, it is difficult to establish the relationship between α7 and Aβ in the pathology of AD as it appears that α7 activation by pΜ concentrations of Aβ is necessary for LTP enhancement, but nanomolar concentrations of Aβ impair LTP and memory (Dziewczapolski et al., 2009).

Conclusion

The relationship between α7 and AD progression is complex. Investigations continue to understand more comprehensively the effect of Aβ on α7 in terms of concentration, molecule type, and time of development.

Further lines of research seek insight into the effect of inflammation, from a variety of causes, on α7 and the overall development of AD. With all this research comes the continuous process of refining the treatment options for patients suffering from AD, a process that any advances in understanding would greatly profit. Finally, there are the challenges in adapting the discoveries in non-humans to clinical treatment of patients that require attention in order to ensure the best possible options for patients.

Future experiments will hopefully shed light on all these areas and yield clarity into the nature of α7 nicotinic acetylcholine receptors on the pathology of Alzheimer’s Disease.

References [1]Bitner, R. S., Bunnelle, W. H., Decker, M. W., Drescher, K. U., Kohlhaas, K. L., Markosyan, S., … Gopalakrishnan, M. (2010). In Vivo Pharmacological Characterization of a Novel Selective α7 Neuronal Nicotinic Acetylcholine Receptor Agonist ABT-107: Preclinical Considerations in Alzheimer’s Disease. Journal of Pharmacology and Experimental Therapeutics, 334(3), 875–886. https://doi.org/10.1124/ jpet.110.167213 [2]Conejero-Goldberg, C., Davies, P., & Ulloa, L. (2008).

Alpha7 nicotinic acetylcholine receptor: A link between inflammation and neurodegeneration. Neuroscience & Biobehavioral Reviews, 32(4), 693–706. https://doi.org/10.1016/j. neubiorev.2007.10.007 [3]Dziewczapolski, G., Glogowski, C. M., Masliah, E., & Heinemann, S. F. (2009). Deletion of the α7 Nicotinic Acetylcholine Receptor Gene Improves Cognitive Deficits and Synaptic Pathology in a Mouse Model of Alzheimer’s Disease. Journal of Neuroscience, 29(27), 8805–8815. https:// doi.org/10.1523/JNEUROSCI.6159-08.2009 [4]Fan, H., Gu, R., & Wei, D. (2015). The α7 nAChR selective agonists as drug candidates for alzheimer’s disease. Advances in Experimental Medicine and Biology, 827, 353–365. https://doi.org/10.1007/978-94-017-9245-5_21 [5]Kita, Y., Ago, Y., Takano, E., Fukada, A., Takuma, K., & Matsuda, T. (2013). Galantamine increases hippocampal insulin-like growth factor 2 expression via α7 nicotinic acetylcholine receptors in mice. Psychopharmacology, 225(3), 543–551. https://doi.org/10.1007/s00213-012-2841-7 [6]Koval, L., Lykhmus, O., Kalashnyk, O., Bachinskaya, N., Kravtsova, G., Soldatkina, M., … Skok, M. (2011). The presence and origin of autoantibodies against α4 and α7 nicotinic acetylcholine receptors in the human blood: Possible relevance to Alzheimer’s pathology. Journal of Alzheimer’s Disease, 25(4), 747–761.

[7]Lewis, A. S., van Schalkwyk, G. I., & Bloch, M. H. (2017).

Alpha-7 nicotinic agonists for cognitive deficits in neuropsychiatric disorders: A translational meta-analysis of rodent and human studies. Progress in Neuro-Psychopharmacology and Biological Psychiatry, 75, 45–53. https://doi. org/10.1016/j.pnpbp.2017.01.001 [8]Lilja, A. M., Porras, O., Storelli, E., Nordberg, A., & Marutle, A. (2011). Functional interactions of fibrillar and oligomeric amyloid-β with Alpha7 nicotinic receptors in Alzheimer’s disease. Journal of Alzheimer’s Disease, 23(2), 335–347.

[9]Liu, Q., Xie, X., Emadi, S., Sierks, M. R., & Wu, J. (2015).

A novel nicotinic mechanism underlies β-amyloid-induced neurotoxicity. Neuropharmacology, 97, 457–463. https://doi. org/10.1016/j.neuropharm.2015.04.025 [10]Lombardo, S., & Maskos, U. (2015). Role of the nicotinic acetylcholine receptor in Alzheimer’s disease pathology and treatment. Neuropharmacology, 96, Part B, 255–262. https:// doi.org/10.1016/j.neuropharm.2014.11.018

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[11]Lykhmus, O., Koval, L., Skok, M., Zouridakis, M., Zisimopoulou, P., Tzartos, S., … Cloëz-Tayarani, I. (2011). Antibodies against extracellular domains of alpha4 and alpha7 subunits alter the levels of nicotinic receptors in the mouse brain and affect memory: Possible relevance to Alzheimer’s pathology. Journal of Alzheimer’s Disease, 24(4), 693–704.

[12]Nery, A. A., Magdesian, M. H., Trujillo, C. A., Sathler, L. B., Juliano, M. A., Juliano, L., … Ferreira, S. T. (2013). Rescue of amyloid-beta-induced inhibition of nicotinic acetylcholine receptors by a peptide homologous to the nicotine binding domain of the alpha 7 subtype. PLoS ONE, 8(7). https://doi.org/10.1371/journal.pone.0067194 [13]Nikiforuk, A., Kos, T., Potasiewicz, A., & Popik, P. (2015). Positive allosteric modulation of alpha 7 nicotinic acetylcholine receptors enhances recognition memory and cognitive flexibility in rats. European Neuropsychopharmacology, 25(8), 1300–1313. https:// doi.org/10.1016/j.euroneuro.2015.04.018 [14]Pirttimaki, T. M., Codadu, N. K., Awni, A., Pratik, P., Nagel, D. A., Hill, E. J., … Parri, H. R. (2013). α7nicotinic receptor-mediated astrocytic gliotransmitter release: Aβ effects in a preclinical Alzheimer’s mouse model. PLoS ONE, 8(11). Retrieved from http://ezproxy.baylor.edu/login?url=http://search. ebscohost.com/login.aspx?direct=true&db=psyh&AN=2014-00906-001&site=ehost-live&scope=site

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Review Articles

Review Assessing the Role of TLR4 Inhibitors in Innate Immune Response Stinchcomb Allie, Alyssa Alaniz , Liam Ferreira Baylor University Abstract The activation of the immune system post-transplant can cause inflammation, leading to graft failure. Toll-like receptor 4 (TLR4) provides a pathway for inflammatory cytokines to be secreted, and recent advances in inhibiting/blocking TLR4 have been shown to increase graft viability and transplantation success. This review will examine the role of TLR4 in post-transplant inflammation and ischemia reperfusion injury (IRI), the effect of TLR4 antagonists post-transplantation, and recent literature regarding different TLR4 antagonists.

Introduction

Organ transplantation provides a viable way of treating organ failure and dysfunction, and new methods of protecting transplanted organs have significantly improved the success of transplantation within the past few years.

Improvements in the methods of matching donors to patients help promote successful grafts and new immunosuppressive treatments allow grafts to survive the attacks of the host’s adaptive immune system. However, clinical graft rejections still pose a significant risk to the viability of transplanted organs.

The three classifications of graft rejections are characterized by the time frame in which the rejection occurs (Ruiz et al., 2013). Hyperacute rejection occurs within the initial few minutes or hours after transplantation. It is caused by the host’s pre-existing antibodies attacking the graft’s major histocompatibility complex (MHC) antigens, which stimulates an inflammatory response that ultimately leads to capillary obstruction and tissue necrosis. This type of rejection is no longer common due to advances in matching techniques and blood typing before organ transplantation (Ruiz et al., 2013; Singh, Pirsch, & Samaniego, 2009).

Acute rejection occurs within days to months after transplantation. It is caused by the development of alloantibodies and alloreactive T cells that react against antigens— mainly MHC antigens—present in the graft that are not present in the host’s red blood cells. The T cells are responsible for creating lesions in the endothelial cells of the graft. These lesions can cause microvascular endothelialitis and arteritis to develop, leading to graft failure. Other alloantibodies cause the graft to become inflamed, leading to coagulation and thrombotic ischemia of the transplant as well. However, acute rejection is also no longer common due to advances in

immunotherapy treatments (Ruiz et al., 2013).

Chronic rejection occurs within months or years after transplantation and is currently the biggest challenge for the procedure. It is caused by chronic secretion of inflammatory cytokines, leading to a subsequent chronic inflammation within the tissue. Insufficient immune system suppression can allow the host to develop donor-specific antibodies (DSA) that bind and injure the graft, causing organ failure. This type of rejection still remains unresolved, and further research is required to discover a remedy (Becker, Morath, & Suesal, 2016; Ruiz et al., 2013).

Ischemia-reperfusion injury (IRI), damage due to the re-oxygenation of hypoxic tissues, leads to an activation of an innate immune response that is detrimental to the health and longevity of a graft. It has been shown that the level of IRI affects the timeframe and severity with which the transplant is rejected (Braza, Brouard, Chadban, & Goldstein, 2016; Chalasani et al., 2004). In order for IRI to occur, the TLR4 / MyD88 dependent pathway must be activated, and inhibition thereof has been shown to prevent IRI in transplanted tissue (Huiling Wu et al., 2007).

Therefore, inhibiting the TLR4 pathway should dramatically increase the viability and longevity of a graft.

Toll-Like Receptor 4 Signaling Pathway

Toll-like receptors (TLR) are a relatively new focus in immunology research. They are expressed as part of the innate immune response that leads to inflammation.

There are a total of ten TLRs in the human body, each of which contain activation sites that are specific for different components of a foreign pathogen (Moresco, LaVine, &

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Beutler, 2011; Nishiya & DeFranco, 2004). TLR4 has several pathogen-associated molecular patterns (PAMPs) that can stimulate the receptor such as lipopolysaccharide (LPS), fusion protein from respiratory syncytial virus, and endogenous molecules such as heat-shock proteins, hyaluronic acid, and β-defensin 2 (Lu, Yeh, & Ohashi, 2008; Nishiya & DeFranco, 2004). Of all of these PAMPs, LPS has been the most studied immunostimulatory component of bacteria as it is an important structural component found in the outer membrane of gram-negative bacteria (Lu et al., 2008).

Figure 1: TLR4 / NFκB Signaling Pathway

The primary signaling pathway (Figure 1) begins with an LPS binding protein binding to the bacterial LPS polymer creating a complex. This complex is then transferred to CD14, a homing receptor found anchored peripherally to the cell membrane of monocytes and macrophages (Jersmann, 2005). CD14 loads the LPS polymer into the ectodomain of the TLR4 where it is identified by the accessory protein myeloid differentiation 2 (MD-2) (Jersmann, 2005; Miyake, 2003; Roman & Dipika, 2000). Once LPS is detected, homodimerization of the TLR4 ectodomains is induced and leads to a conformational change of the complex consisting of CD14, TLR4 dimer and MD-2 (Lu et al., 2008). This conformational change initiates the dimerization of cytoplasmic toll interleukin L-1 receptor (TIR) that recruits one of five different adaptor proteins such as myeloid differentiation protein (MyD88), TIR domain containing adaptor protein (TIRAP), TIR domain-containing adaptor protein inducing IFN-Beta (TIRF), TRAM (TRIF- related adaptor molecule), and SARM (sterile alpha and HEAT-Armadillo motifs-containing protein) to form a post-receptor signaling complex (Apos, Neill, & Bowie, 2007).

TLR4 has both a MyD88-dependent pathway and a MyD88 independent pathway (Adachi et al., 1998). The dependent and independent pathways mediate the activation of proinflammatory cytokines and Type I interferon genes

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respectively. Both pathways turn on the primary transcription factor, nuclear factor kappa B (NFκB). NFκB is the major initiator of inflammation and is kept in the cytoplasm by inhibitor kappa B (IκB). The phosphorylation of IκB frees NFκB to translocate to the nucleus and initiate transcription of designated inflammatory genes. After transcription, effectors of the innate immune response such as cytokines and chemokines are synthesized and lead to an inflammatory response to block the growth of bacteria (Lu et al., 2008; Moresco et al., 2011).

Ischemia Reperfusion Injury Occurring After Kidney Transplant and Leading to Acute Renal Failure

Ischemia reperfusion injury (IRI) occurs within the renal system inevitably after a kidney transplant leading to negative repercussions in both long term and short-term survival of the recipient (Parker, Arslan, Keogh, & McGuirk, 2010; H. Wu, 2010). IRI is caused by the activation of the inflammatory response resulting in endothelial activation and injury, enhanced endothelial cell-leukocyte adhesion, leukocyte entrapment, and a compromise in microvascular blood flow (Bonventre & Zuk, 2004). This loss of blood flow to regions or the entirety of the kidney lead to acute renal failure (ARF). Acute renal failure is also the product of sepsis, in which an LPS endotoxin is released which acts on extrarenal TLR4 and leads to tumor necrosis factor (TNF) being released.

TNF has been shown to be responsible for the initiation of apoptosis to epithelial renal cells throughout the renal system (Cunningham, Wang, Guo, He, & Quigg, 2004). While TLR4 is the primary topic of this paper, it is also important to note that TLR2 is also a key receptor in the inflammatory response (Rusai et al., 2010). Studies of knockout mice have been conducted to further determine whether TLR4 and TLR2 are the primary causes of ARF by testing the effects of a nephrotoxin on both TLR4 and TLR2 deficient mice as well as MyD88 independent and dependent pathways to try to fully understand the inflammatory pathway.

Once it was discovered that both TLR4 and TLR2 are utilized in IRI and ARF, mouse studies were conducted to knockout each individually and then both of them together. Results showed that disabling both does not increase the effectiveness of the protection against the inflammatory response when compared to separately disabling TLR4 and TLR2 (Rusai et al., 2010). This demonstrated that the TLR4 and TLR2 may prime each other during reperfusion injury (Cunningham et al., 2004).

Knockout bone marrow and TLR4 deficient mice demonstrated a tolerance to the nephrotoxin, whereas wildtype mice had significant tissue damage and showed signs of ARF after one hour (Zhang, 2008). When transplantation occurs, it can be hypothesized that similar results will arise.

If there is no TLR4 on the renal epithelial cells to begin the inflammation process, then transplantation of a kidney donor

that is a match will not demonstrate such a high risk of ARF or IRI occurring (Cunningham et al., 2004).

Further knockout mice studies demonstrated MyD88 deficient mice were protected against inflammatory response and kidney damage, although not as efficiently as targeting TLR4 on its own, concluding that IRI uses a MyD88 dependent TLR4 pathway (Pulskens et al., 2008; Huiling Wu et al., 2007).

In order to combat the renal failure and injury that occurs after transplantation, this research suggests that the TLR4 and TLR2 pathway is the primary cause of IRI and ARF (Parker et al., 2010). From there, the details of the TLR4 pathway of this condition remains a matter for additional study (Zhang, 2008).

Neural cells and Ischemic Stroke

IRI, tissue damage due to the re-oxygenation of hypoxic cerebral tissues, is also induced by the activation of the toll-like receptor 4 (TLR4) pathway (Gao, Fang, Tong, Liu, & Zhang, 2009). Inhibition of the TLR4 pathway has been shown to prevent damage to neural cells and curb the damaging inflammatory effects of ischemic stroke (Liu et al., 2016). One promising area of research is the development of a method of transplanting neural stem cells (NSC) after ischemic stroke to aid in neuroregeneration (Bacigaluppi, Pluchino, Martino, Kilic, & Hermann, 2008; Vladimer et al., 2010). However, one complication is cell death after NSC transplantation into the hostile ischemic environment (Joshua et al., 2017). It can be hypothesized that if the initial IRI can be ameliorated, the efficacy of the neural stem cells should increase, and perhaps future investigation can determine whether TLR4 inhibitors can directly protect the NSCs.

Nevertheless, it has been demonstrated that ameliorating IRI by inhibiting the TLR4 pathway is possible, and several TLR4 inhibitors have been tested in mouse models.

For this review, three inhibitors were chosen that were tested on mice, PC12 cells, and primary cortical neuron cells, and the results appear to be promising in relation to increasing cell viability in the aftermath of ischemic stroke.

Daphnetin, Salvianolic Acid B (SAB), and Dioscin have all been shown to successfully ameliorate cerebral injury from ischemia reperfusion by inhibition of the TLR4 pathway (Abdoulaye & Guo, 2016; Liu et al., 2016; Tao et al., 2015; Y. Wang et al., 2016).

Daphnetin, SAB, and Dioscin were tested on mice that underwent induced middle cerebral artery occlusion (MCAO), and Dioscin and SAB were tested on PCN and PC-12 cells in addition to on mice. These compounds were found to significantly decrease the expression of inflammatory proteins TNF-α, IL-1β, and IL-6, and decreased the neurological score of MCAO mice, in which a higher score means more neurological damage (Liu et al., 2016; Tao et al., 2015; Y. Wang et al., 2016).

Daphnetin (Figure 2), a natural derivative of coumarin, plays a significant role in inhibiting tumor necrosis factor-α (TNF-α) mediated NFκB expression. It does so by interfering with the NFκB pathway by preventing phosphorylation of the NFκB inhibitor IκB. This in turn ameliorates the activity of NFκB transcription units and NFκB cytoplasm subunits as well (Kumar, Sunita, Jha, & Pattanayak, 2016).

Figure 2: Chemical Structure of Daphnetin

SAB (Figure 3) (Ai & Li, 1988), derived from a traditional Chinese herb, is known to exhibit anti-oxidative and anti-inflammatory effects and can inhibit LPS induced inflammation (Chen et al., 2011). It does so by targeting and inhibiting the TLR4 / NFκB pathway in a dose dependent manner (J. Wang, Xiong, & Feng, 2013). By inhibiting the TLR4 pathway, it attenuates production of LPS induced pro-inflammatory cytokines such as TNF-α and interleukin-1β (IL-1β). SAB also mediates expression of nitric oxide synthase (iNOS), TNF-α, and IL-1β mRNA, which can be activated by NF-κB (S.-X. Wang, Hu, Gao, Guo, & Fan, 2010).

Figure 3: Chemical Structure of Salvianolic Acid B (SAB)

Similarly, Dioscin (Figure 4) is also obtained from a traditional Chinese medicine and ameliorates IRI by inhibiting the TLR4 / NFκB pathway. Dioscin has been found to down-regulate expression of both NFκB and MAPK signaling pathways, which decreases expression of the IL-10 pro-inflammatory cytokine and TNF-α and IL-6 cytokines (Qi et al., 2015).

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— potent vasoconstrictors that induce hypertension and subsequent cardiac remodeling (Dange et al., 2014; Zhang et al., 2015). Angiotensin II (AII) stimulates the TLR4 pathway and induces an inflammatory response leading to ventricular damage (Zhang et al., 2015). In fact, central TLR4 signaling in the paraventricular nucleus (PVN) of the hypothalamus is also instrumental in contributing to hypertension. Research revealed that rats treated with AII and the TLR4 blocker, viral inhibitory peptide (VIPER), showed a decrease in hypertrophy and mean arterial pressure. TLR4 inhibition attenuates the myocardial inflammatory response, which leads to the symptoms of hypertension (Dange et al., 2014).

Figure 4: Chemical Structure of Dioscin

Both SAB and Dioscin were tested on PCN and PC12 cells in differing doses in similar environments.

Both significantly increased cell viability in ischemic en-

vironments in a dose dependent manner (Tao et al., 2015; Y. Wang et al., 2016). SAB, Dioscin, and Daphnetin have been tested on mice models and were found to significantly decrease the neurological damage and infarct volume in pre-treated mice (Liu et al., 2016; Tao et al., 2015; Y. Wang et al., 2016). These findings hold potential for further investigation into TLR4 inhibitors and ischemic injury.

Cardiovascular Remodeling

With the incidence of obesity rising, hypertension and chronic inflammation are major contributors to the development of cardiovascular disease. Research on TLR4 knockout mice has shown that TLR4 deficiency results in decreased levels of inflammation and cardiac remodeling (Hu & Zhang, 2017).

While the inflammatory response of TLR4 has been linked with hypertension-associated cardiac remodeling, no evidence has shown a clear relationship between left ventricular damage and hypertension (Echem et al., 2015).

After showing the positive correlation between an increase in TLR4 expression and hypertension, research used anti-TLR4 therapy and non-specific IgG antibody treatment in spontaneously hypertensive rats (SHR) to determine the cause of cardiac remodeling. Histological analysis revealed that IgG treatment did not lead to changes in left ventricular composition while anti-TLR4 therapy led to a decrease in myocyte size and left ventricular collagen. Most importantly, anti-TLR4 therapy reversed the damage to cardiomyocytes while not affecting blood pressure. The experiment showed that left ventricular remodeling is largely independent of rising blood pressure and induced by the inflammatory pathway of TLR4. (Echem et al., 2015). Decreasing expression of TLR4 prevents hypertrophy and reactions to subsequent viral reactions after cardiac overload (Ehrentraut et al., 2015; Wang, Zhu, Xiong, Zhang, & Ren, 2016).

The Renin-Angiotensin-Aldosterone System (RAAS) leads to the production of Angiotensin II and Aldosterone

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The small-molecule TAK-242 is a potent anti-inflammatory suppressant that binds to the intracellular portion of TLR4 (Matsunaga, Tsuchimori, Matsumoto, & Ii, 2011).

Studies have shown that Aldosterone (Aldo) led to an increase in TLR4 gene expression in rats, and histological analysis shows that TAK-242 can reverse the progression of hypertension In experiments where rats were given an Aldo-salt and TAK-242 treatment, the rats showed a decrease in myocardial fibrosis. Cardiomyocytes of those rats also showed a decrease in inflammatory cytokines and fibrotic factors (e.g. Collagen type 1 and transforming growth factor-β).

These results demonstrate that TAK-242 is a promising solution for cardiovascular disease by inhibiting the TLR4 signaling pathway (Zhang et al., 2015).

Myocardial inflammation is a key step in the pathogenesis of cardiovascular diseases such as myocarditis, myocardial infarction, and myocardial ischemia/ reperfusion (MIR) injury (Yang et al., 2016). Although TLR4 has a beneficial effect in viral myocarditis by activating IFN-β through the MyD88-independent pathway, TLR4 usually leads to an increase in cytokine production which exacerbates the inflammatory process in cardiovascular disease (Feng & Chao, 2011; Ha et al., 2011; Yang et al., 2016). During MIR, sudden restoration of blood flow after occlusion results in tissue damage from the innate immune response (Lee, Hutchinson, & Saint, 2016; Lu et al., 2015). In ischemic tissue, damaged cells release DAMPs which initiate the TLR4-signalling pathway, further damaging the tissue (Feng & Chao, 2011; Yang et al., 2016). Although TLR4s on leukocytes contribute to the inflammatory response, the cardiomyocyte TLR4s amplify the inflammatory response in ischemic tissue (Liu et al., 2015).

Figure 6. Structure of Astragaloside IV (AsIV)

Astragaloside IV (AsIV) is isolated from the herb Astragalus membranaceus. AsIV can alleviate many symptoms of cardiovascular disease and attenuates the effects of inflammation initiated by the TLR4 pathway in response to ischemia (Zhang et al., 2011).

Figure 5. Chemical Structure of Eritoran

Eritoran (Figure 5), a TLR4 antagonist, decreases infarct size in cardiac cells (Ha et al., 2011). It is able to prevent LPS from binding to the TLR4 activation site, thus inhibiting the inflammation that would occur as a result (Opal, Laterre, Francois, & et al., 2013). New pharmaceutical research also demonstrated that anti-inflammatory Astragaloside IV (AsIV) inhibits the TLR4 / NF-ÎşB pathway. The tissue of rats administered AsIV (Figure 6), following simulated MIR, showed a decrease in infarct size, myocardial distortion, and serum levels of TNF- Îą and IL-6.

The results of the MIR study showed that AsIV attenuates the effects of MIR by inhibiting the TLR4 signaling pathway (Lu et al., 2015).

Eritoran is a synthetic TLR4 antagonist derived

from LPS. Although structurally resembling LPS, Eritoran prevents the initiation of the TLR4 inflammatory response. The shortened lipid portions of the antagonist bind to the MD-2 complex that interacts with TLR4. Both ligands, Eritoran and LPS, compete for the same binding region in the TLR4 pathway. Administration of Eritoran saturates the MD-2 binding sites and prevents the binding of LPS (Jin & Lee, 2008).

Conclusion

Recent advances hold significant potential for increasing the viability and longevity of transplanted tissues.

Future efforts will hopefully yield the ability to selectively inhibit particular aspects of the immune system in a dose dependent manner. Until then, the scientific community will continue to perform research focused on reducing the quantity and severity of graft rejections. The research regarding TLRs appears to be a key focus, and future discoveries about TLR4 inhibition may aid in the goal of someday eradicating graft rejection and failure.

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JAMA, 309(11), 1154-1162. doi:10.1001/jama.2013.2194 [19]Parker, A. E., Arslan, F., Keogh, B., & McGuirk, P. (2010). TLR2 and TLR4 in ischemia reperfusion injury. Mediators of Inflammation, 2010, 1-8.

[20]Pulskens, W. P., Teske, G. J., Butter, L. M., Roelofs, J. J., van der Poll, T., Florquin, S., & Leemans, J. C. (2008). TollLike Receptor-4 Coordinates the Innate Immune Response of the Kidney to Renal Ischemia/Reperfusion Injury. PLoS ONE, 3(10), e3596.

[21]Qi, M., Zheng, L., Qi, Y., Han, X., Xu, Y., Xu, L., . . . Peng, J. (2015). Dioscin attenuates renal ischemia/reperfusion injury by inhibiting the TLR4/MyD88 signaling pathway via up-regulation of HSP70. Pharmacological Research, 100(Supplement C), 341-352.

[22]Roman, D., & Dipika, G. (2000). Role of MD-2 in TLR2and TLR4-mediated recognition of Gram-negative and Gram-positive bacteria and activation of chemokine genes.

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[24]Rusai, K., Sollinger, D., Baumann, M., Wagner, B., Strobl, M., Schmaderer, C., . . . Lutz, J. (2010). Toll-like receptors 2 and 4 in renal ischemia/reperfusion injury. Pediatric Nephrology, 25(5), 853-860.

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[26]Tao, X., Sun, X., Yin, L., Han, X., Xu, L., Qi, Y., . . . Peng, J. (2015). Dioscin ameliorates cerebral ischemia/reperfusion injury through the downregulation of TLR4 signaling via HMGB-1 inhibition. Free Radical Biology and Medicine, 84(Supplement C), 103-115.

[27]Vladimer, D., Susan, J. A., Carlo, C., Emanuela, M., Daniela, K., Therése, K., . . . Zaal, K. (2010). Cell Number and Timing of Transplantation Determine Survival of Human Neural Stem Cell Grafts in Stroke-Damaged Rat Brain. Journal of Cerebral Blood Flow & Metabolism, 31(1), 235-242.

[28]Wang, J., Xiong, X., & Feng, B. (2013). Cardiovascular Effects of Salvianolic Acid B. Evidence-Based Complementary and Alternative Medicine, 2013, 16.

[29]Wang, S., Zhu, X., Xiong, L., Zhang, Y., & Ren, J. (2016).

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2017 URSA Winners Abstracts

Psychology and Neuroscience Testing Prospective Memory Theories with MouseTracker Trajectories Kiersten A. Scott; Mentor Michael K. Scullin, Ph.D. Prospective memory refers to remembering to complete a future task, such as remembering to read for a class or to return to the washer at the appropriate time. The Multiprocess Theory states that spontaneous retrieval, or automatic remember-ing due to environmental cues, initiates prospective memory. Existing evidence for spontaneous retrieval arises from slowed reaction times relative to control items when a prospective memory cue is presented in an unexpected context.

However, reaction times only indirectly support cue driven spontaneous retrieval. In contrast, MouseTracker software can visualize cursor trajectories, velocities, and acceleration, thereby providing greater insight into mental processes during cue presentation. In the present experiment, participants learned a word or a non-word decision task by selecting boxes in the top right or left-hands of a computer screen, respectively. They were then instructed to select a third box in the bottom right hand corner if the target words “corn” or “dancer” were present (i.e., prospective memory task). Following a performance phase, participants were instructed either to suspend the prospective memory task for the next phase, or that their prospective memory task was finished. Regardless, the target words were re-presented in the following block. Based upon pilot data we hypothesize that participants will show mouse cursor trajectories toward the prospective memory response during target trials (bottom right corner) in the suspended, but not the finished, condition. Such a finding would provide strong evidence that spontaneous retrieval is the primary method of retrieval for active prospective memory tasks.

Understanding the Mechanisms of Susceptibility Genes Implicated in Autism Spectrum Disorders Kayla Murphy (Baylor), Kara Barber and Keegan Bush (Neurology Department at University of Texas Medical Branch, Galveston); Mentors: Yogesh Wairkar, Ph.D. (Neurology Department at UTMB, Galveston) and Bob Kane, Ph.D. Autism Spectrum Disorders (ASD) affect 1 in 68 children worldwide. Previous research has indicated a strong genetic component through the identification of many susceptibility genes, many of which affect synapse growth and development.

MARK1 is one gene that was found to be upregulated in the prefrontal cortex of ASD patients. Previous research from our laboratory has shown that neuronal overexpression of Par-1, its Drosophila homolog, leads to a specific accumulation of Bruchpilot (BRP) within axons. Since alteration in gene dosage is highly implicated in ASD, we aimed to test the hypothesis that the correct gene dosage of Par-1 is critical for effective BRP and/or active zone protein transport. We looked at the reduction of Par-1 by using RNAi of Par-1(Par-1 RNAi) and mutations in fat facets (faf). Mutations in faf, a deubiquitinating enzyme, prevent the deubiquitination of Par-1 leading to a reduction of Par-1 levels in vivo. Through Drosophila larval dissection and immunohistochemical staining of the exposed neuromuscular junctions, we found that Par-1 RNAi and faf lead to a specific accumulation of active zone proteins in axons. However, other synaptic cargoes did not accumulate in axons. This data confirms our hypothesis that gene dosage of Par-1 specifically affects active zone protein transport. peutic benefit to subjects without pre-existing cognitive dysfunction.

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A Mouse Model of Fragile X Syndrome Exhibits Qualitative Deficits in Vocalization Behavior Kaylin Ackerman, Samantha Hodges, Suzanne Nolan, and Conner Reynolds; Mentor: Joaquin Lugo, Ph.D. The Fmr1 knockout (KO) mouse has commonly been used to investigate communication impairments, one of the key diagnostic symptoms, observed in Fragile X syndrome (FXS) and Autism spectrum disorder (ASD). Many studies have found alterations in ultrasonic vocalizations (USVs) in neonatal Fmr1 KO mice, however, there is limited research investigating whether these deficits continue into adulthood. In the present study, we examine differences in female urine-induced ultrasonic vocalizations, scent marking behavior, odor discrimination, and open field activity in adult male Fmr1 KO and WT mice. Overall, we found extensive alterations between genotypes in both spectral and temporal properties of vocalizations. There was no difference in the average number of calls emitted by both genotypes, however, Fmr1 KO mice emitted calls of a higher frequency, decreased amplitude, and shorter duration than WT mice. Spectrographic analyses revealed significant differences between genotypes in the types of calls emitted. Contrastingly, we found no differences in scent marking behavior, a form of social communication, or in odor discrimination and activity levels of the mice. The results corroborate previous studies emphasizing the importance of qualitative differences observed in vocalization behavior of Fmr1 KO mice, rather than quantitative measurements such as number of calls emitted. Overall, the study confirms the presence of significant abnormalities in vocalization behavior in adult Fmr1 KO mice that we believe are consistent with communication deficits seen in the syndrome.

Geology A Geological Comparison of the Oil Shale, Natural Gas, and Nahcolite Resources of the Piceance Basin and their Associated Extraction Methods Hayden Ross; Mentor: Wayne Hamilton, Ph.D. The Piceance Basin of the Green River Formation in northwestern Colorado contains an abundant accumulation of natural gas, oil shale, and nahcolite. This basin contains the single largest accumulation of oil shale deposits in the world with an estimated in-place value of 1.5 trillion barrels. Natural gas is currently being produced from the basin out of tight sands and coal seams using modern methods of hydraulic fracturing. The Piceance Basin also contains the second largest deposit of nahcolite in the world. Such a large energy potential is contained within the basin, and newer techniques of extraction will be needed to utilize its full potential. A high percentage of federal land covering the basin, combined with energy intensive extraction methods have made production only viable during higher oil and gas prices. Environmental impacts with current production methods have also hindered extraction in this area. This research will attempt to give the most viable extraction method for each resource based on depth, cost, environmental impact, and areas where the resource is most abundant. Various publications were collected and compiled in the attempt to better understand this complex and mineral-rich basin. The most efficient extraction methods were chosen using the compare and contrast diagram made after gathering all data. After comparing and contrasting the different production methods for each resource based on the criteria, the results indicate that in-situ methods need to be used for oil shale and nahcolite production.

Current methods of hydraulic fracturing have proven to be economic and environmentally safe to use for natural gas. Although the in-situ methods of recovery have proven to have a high success rate of both oil shale and nahcolite, they have a high-energy intake making it uncompetitive against modern methods of obtaining crude. Natural gas production in the basin has spiked in recent years as more efficient methods of hydraulic fracturing have been developed. A huge resource is contained within the basin, but better methods of extraction for oil shale and nahcolite will need to be developed to get the full potential out of the basin while also satisfying strict environmental policies.

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Physics Orbit Determination of 2004 Lexell: Applying Gauss’s Method Thayer Walmsley; Mentor: Dwight Russell, Ph.D. Orbits are uniquely defined by six orbital elements. The goal of this research project was to determine the viability of using Gauss’s Method to determine these elements for 2004 Lexell. The asteroid was chosen based on its size and ability to be observed from the Paul and Jane Meyer observatory during the research period. Gauss’s method requires three position measurements of right ascension and declination as well as the time intervals between them. A key determinant in the viability of this method is these time intervals. The research assessed what range of time intervals produced reasonable orbits for the asteroid. Observations were conducted using a 24 inch Ritchey-Chretien reflective telescope. Supplemental data was obtained from the IAU minor planet data center.

Chemistry and Biochemistry Thiosemicarbazone Compounds as Inhibitors of Cruzain for the Potential Treatment of Chagas’ Disease Tuate Dambo; Mentors: Mary Trawick, Ph.D., Samuel Odutola, Ph.D., Erica Parker, Ph.D., and Kevin Pinney, Ph.D. Trypanosoma cruzi (T. cruzi) is the parasite that causes Chagas’ disease. Charles Darwin was said to have died from the symptoms of Chagas’ disease. T. cruzi is in the same phylum (phylum Kinetoplastea) as the parasite that causes sleeping sickness (T. brucei). Cruzipain is the major cysteine protease of T. cruzi. It is a sulfated glycoprotein that plays a major role in the metabolism and life cycle of the parasite—which makes the inhibition of cruzipain an effective criterion for drug design. A recombinant form of cruzipain known as cruzain—which a member of the papain family and a cathepsin-L like enzyme was used in this study. Thiosemicarbazone compounds are efficient in the inhibition of cathesin-L. In a collaborative project between the Trawick and Pinney research groups at Baylor University, the reactions tween different thiosemicarbazone compounds (less than 10 µM) and cruzain substrate Z-Phe-Arg-AMC in the presence of an enzyme were monitored using a fluorogenic enzyme assay. The enzyme assay measured the cleavage of 7-amino-4-methylcoumarin (AMC, a fluorescent compound) from Z-FR-AMC (a non-fluorescent compound). IC50 was used to measure the concentration of the compound required to reduce cruzain activity by 50%.

Biology A Cost-Effective Design For A Laparoscopic Box Trainer Austin MacDonald and Davis Payne; Mentor: Marty Harvill, Ph.D. The development of laparoscopic surgical methods began in the early 1900s and emerged as a staple of multiple surgical fields in the 1990s. However, it was discovered that the skills associated with open surgery did not fully translate into the skills required for the successful completion of a laparoscopic case. Two common challenges associated with laparoscopic surgery are lack of coordination with the instruments and loss of depth perception due to the use of a camera for visualization. Due to these obstacles, various methods have been designed and implemented to create training programs of sufficient efficacy. Different modes of training range “box” trainers to surgical simulations carried out 40 through virtual reality programs. Our goal was to create a cost-effective box trainer that would allow a person to effectively improve their performance in completing laparoscopic exercises. The trainer and exercises were inspired by various designs used by training programs today. The efficacy of the trainer was tested by undergraduate students with little to no knowledge concerning the field of laparoscopic surgery.

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The Effects of Dopamine on Egg Laying Behaviors of Caenorhabditis elegans Susana Diaz, Ialexa Plascencia, Jordan Spaude, and William Townsend; Mentor: Myeongwoo Lee, Ph.D. There are four dopamine receptors in C. elegans and eight dopaminergic neurons in the nervous system. The dopaminergic neurons are classified dependent on their location in the body. There are four that innervate the tip of the nose, 42 two innervate the head cuticle and two innervate the posterior cuticle. C. elegans has two D1-like receptors, dop-1 and dop-4, and two D2-like receptors, dop-2 and dop-3. Dopamine has been related to locomotion and sensory perception of surroundings. Dopamine has been shown to inhibit locomotion and egg-laying as well as having modulatory purposes in crawling speed in response to food. When exposed to food, the dopamine signaling pathway, containing the DOP3 receptor, is utilized and causes a slowing response in order to remain near the food source. Dopamine has also been associated with learning and memory in C. elegans, such as tap habituation. Dopamine has been shown to inhibit defecation as well. As a project for our Cell and Developmental Biology Lab, we will create various mutants for resistance to the effects of dopamine and be determining how dopamine is inhibiting the egg-laying in C. elegans. The new mutants will be important in understanding how the mechanism of dopamine in animal behavior.

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Student Research Spotlight A Survey of Undergraduate Research in Baylor University, Waco, Texas Navin Kumar - Class of 2021

I am currently taking a fantastic research course offered to undergraduate students called BIO 1V90.

This course is mainly dealing with laparoscopy tools and shows how to properly perform laparoscopy using a laparoscopy simulator. Later in the first semester, we had the opportunity to test different scenarios that a surgeon might face when doing laparoscopy trials. My lab partners and I tested the effect of muscle fatigue on laparoscopy surgery, an idea we had when we realized how long surgeries last. We had researched and found that a lot of surgeons face muscle fatigue during long hours of surgery and we wanted to see if this idea could be applied to our laparoscopy class.

I have always wanted to do research and this class is designed to give freshman students the tools they need in order to do later research during their college careers. In the beginning, I started going to a two hour session where I began to try out how to use the tools and other materials that I would later need when doing research. During this time, I realized that practice truly makes perfect and in order to master the science of laparoscopy, I would need a lot of practice. I mainly took this course because I wanted to understand the fundamentals of research while being able to network with surgeons that have been guest speakers in the program. I think that the biggest challenge I truly overcame this past semester was being able to persist, even if error occured. Our project did not go right in many ways, yet I feel as if I grew from the experience and came to appreciate science even more. I used this as an opportunity to understand where our group went wrong and to discover new methods we could use to improve our research for the following semester. I realize that many times my experiments may not go â&#x20AC;&#x153;according to planâ&#x20AC;?, but I should be prepared in that case to improvise. I understand that the workload of the laparoscopy research project was very large at times but because of my amazing lab group, we were able to come together and finish all assignments to the best of our abilities. I am excited for this upcoming semester because I have new opportunities to explore the research that I could do for not just laparoscopy, but other types of surgery as well.

Andrew Burry - Class of 2021

I participate in research at the Waco Family Health Center to assist with the collection of data from their patients. Up until this point, these survey questions were recorded on paper and then transferred to the computer, so this app will be a huge help in increasing the efficiency of the researchers. I personally worked on Authitication and Database management for the project while also helping with the flowchart for the app. I wanted to do research to get some experience making apps, apps seem to be a way to get rich quick and I figured this would give me the experience I would need if I ever had a good idea. I have learned alot about teamwork within agile development, and collaboration with my partner on various bugs we have had to deal with. Overall it has been a great experience and taught me a lot about becoming an engineer.

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Christina Gaw - Class of 2020

I started my research at Baylor University through the summer research program Baylor offers to its incoming freshmen. I had the opportunity to spend the second half of my summer in Dr. Solouki’s analytical chemistry lab. While I had little background with the topics that the Solouki lab explored, I spent time reading material relevant to the lab’s research interests and learning from the graduate students. Since then, I have gained knowledge and still continue to learn from my experiences in the lab. During my time as a member of the group, I have been working on projects related to a new method of detection called the vacuum ultraviolet photospectrometer (VUV) for more confident analyte detection. I have been involved with sample preparation, data collection, and data processing. In addition, through the lab, I have had opportunities to attend conferences and present the work I have been a part of at other universities. When I began my academic career at Baylor, I had no idea how much of an impact research would have on me. Now, I look forward going into the lab between and after classes to work on projects and learning more about topics in chemistry.

For Prospective Authors

We thank you for your interest in reading this journal. Through this journal, students and members of faculty have diligently and passionately devoted their time to promote an atmosphere of scholarship and academic curiosity. It is our hope and desire to see that our readers are both intrigued and inspired by the level of curiosity demonstrated through the research done here by Baylor’s very own. With this motivation instilled in students, we are looking forward to beginning the submission process for Scientia 2019.

Acceptance to Scientia is an achievement that demonstrates independent curiosity and willpower, as well as one’s desire to take initiative to participate in substantial research opportunities at Baylor University. In a world of academia, being a published author, no matter the caliber of the journal published in, demonstrates academic curiosity and extensive inolvement in research. We offer this journal as a very strong starting point for excellent undergraduates at Baylor to publish and showcase their work. Acheiving a publication in Scientia may lead to further opportunities for larger and higher-level experiences in research, since publication proves a higher level of commitment and interest towards conducting serious research than instilled in the average undergraduate student.

We enourage undergraduate researchers at Baylor to consider Scientia as a platform by which to inspire others to participate in research, and a means to demonstrate their own passion and experience in research. Again, we appreciate your interest in Scientia, and we hope to see a commitment and growth of that in the coming years.

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Scientiaâ&#x20AC;&#x2122;s Mission Scientia shall provide a professional platform upon which undergraduates of Baylor University are able to publish personally conducted and outstanding research in the areas of biological sciences, physical sciences, mathematics, and technology.

Accepted Formats Research Articles presenting major findings performed by current undergraduate level students enrolled at Baylor University. Research articles must include an abstract, introduction, materials and methods, results, and discussion.

Review Articles synthesizing developments of interdisciplinary significance written by current undergraduate level students enrolled at Baylor University. Review articles must include an abstract and an introduction outlining the topic of discussion.

Abstracts proposing research topics currently being investigated by current undergraduate level students enrolled at Baylor University.

Submitting to Scientia To submit to Scientia for publication, email your research article, review article, abstract, or Student Spotlight Submission to Jianna_Lin@baylor.edu To read previous editions of Scientia online, please visit https://www.baylor.edu/burst/index.php?id=930886 For more information, including the official Scientia 2019 Submission Guidelines Packet, please email Scientiaâ&#x20AC;&#x2122;s Editor in Chief, Jianna Lin, at Jianna_Lin@baylor.edu

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Freshman Dustin Sanford works on a research project in the Baylor University SPARK laboratory. Read his article on page 12.

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