Oculus Science Journal
Issue 6
FOCUS — Superpowers becoming reality: cephalopods as the next Wright brothers? By JIWON LEE Invisibility, like flying, superstrength, and other superpowers, has long resided in human imagination. However, it is no longer an impossible feat. In fact, it has never been entirely unfeasible, with many animals having developed intrinsic methods of achieving near-invisibility. Light manipulation is vital to achieve transparency; in the end, visibility is determined by how light strikes an object and bounces back into our retina, which then converts the light to neural signals that are transported to our brains. If the light that initially strikes the object fails to reach our eyes, then we would not be able to see the object. This is the logic behind cellular invisibility: maximizing the light that passes through the cells while also minimizing the amount of light that reaches our eyes through diffusively reflecting light rays. This is why natural invisibility is more frequently observed in aquatic organisms than is in terrestrial ones—the refractive index of water is greater than that of air, and is thereby much closer to the refractive index of living tissue. A greater refractive index disparity leads to a greater surface reflection, discouraging the evolution of transparency in animals. Greater amounts of surface reflection mean that the light bouncing off the animals are more likely to reach our retina, thereby making them visible to us. Moreover, terrestrial animals require cellular pigment for protection against ultraviolet radiation, another hindrance for their invisibility. This pigment—melanin, to be exact—is necessary to convert radioactive rays into heat through a very rapid chemical process, preventing the ultraviolet ray from harming cells. While land animals that are frequently exposed to direct light require this protective pigment, aquatic animals are subject to a smaller amount of light given that it is difficult for sunlight to penetrate through water, and therefore are able to sacrifice skin pigment for a better chance at survival. Generally, cephalopods—the animal class including squid, octopus, and cuttlefish—able to mimic transparency do so with leucosomes, which are protein structures with the ability of increasing the scattering visible light. These leucosomes contain reflectins, proteins with unique amino acid sequences that give them a high refractive index and the ability to self-assemble. These two characteristics give the animals the ability to turn partially transparent at their will: the high refractive index helps them scatter more light, while self-assembly allows these animals to change the orientation of their proteins in response to external threats, such as predators, turning them invisible. However, the structural differences between human cells and those of invisibility-possessing animals has been a major obstacle in the step toward human invisibility, as human cells do not possess leucosomes.
Figure 1: A close-up view of the reflectin structures that make up leucosomes, protein structures in cephalopods that serve to scatter visible light. Reflectins contain unique amino acid sequences that give them high refractive indices and the ability to self-assemble, allowing cephalopods to turn partially transparent at will. Source Credit: Nature.com (L ​ INK​) Another vital factor of transparency is the random orientation of the nanostructures responsible for reflecting and changing the direction of light. The glasswing butterfly, for example, has transparent wings caused by nanopillars covering its body. With random heights and widths, these pillars contribute to creating the optical illusion of invisibility for the animal. The primary function of these nanopillars is to minimize the light that bounces off the wings of the butterfly, and for the light that does, vary the direction of the rays such that a minimal number of them travel to our retinas. Despite being a terrestrial animal, the glasswing butterfly is able to achieve partial transparency through employing random nanostructuring. However, given the difference between human skin and the thin membrane of a butterfly wing, drawing inspiration from this form of transparency-generation posed yet another challenge.
Figure 2: A picture of the glasswing butterfly, which exhibits uniquely transparent wings. This is largely due to their low absorption levels of light and minimal scattering of light that passes through its cells. Source Credit: Prince Edward Island Preserve Company (​LINK​) A team of researchers was able to overcome these biological shortcomings, modifying human cells by giving them a protein-based, photonic structure to make it reconfigurable, allowing these cells to appear transparent through light manipulation. Moreover, by designing these human cells to be responsive to stimuli, the scientists were able to have them change their appearance and interactions with light through organized cues, similar to how transparency-achieving cells work in animals. This design was primarily influenced by cephalopods, which have pigment organs that allow them to alter how their skin receives, absorbs, and reflects light. With these methods of camouflage and transparency, these animals have developed unique survival techniques through generations of evolution. It is generally believed that the pigment organs in these animals consist of tunable leucophores, which contain the aforementioned leucosomes in disorderly arrangement. Varying diameters and widths have further improved the light-scattering abilities of these leucosomes, leading scientists to experiment with the implementation of similar designs in human cells. Initial experiments were conducted on Human Embryonic Kidney 293 cells, given their high tolerance for foreign biomolecules and their desirable production of recombinant proteins.
Moreover, the scientists chose the reflectin A1 isoform to build the protein structures out of, given the material’s large refractive indices. Arranging these proteins into strength-responsive structures, the scientists were able to mimic the behavior of squid skin cells. Additionally, upon interaction with chemical stimuli, these modified cells were also able to reconfigure their internal architectures to scatter and transmit different amounts of visible light, thereby altering the transparency level of the cells. Although having long been solely part of our imagination, human invisibility is now on the horizon. While this signifies a great step in modern scientific development and heralds even more radical breakthroughs in the future, we must keep in mind that with new technologies come new responsibilities. Harry Potter using the Cloak of Invisibility to explore Hogwarts after curfew might have seemed fairly exciting, but substituting the situation with a criminal infiltrating government headquarters makes it anything but fun. Invisibility is a new power we may develop; but it is, in the end, a mere tool. The hands that hold it will determine its lasting impact on human society, and whether it is used for good or evil is entirely up to them.
Q&A: Sally: If animals have both melanin and leucosomes, can they possibly be invisible? - Yes: in fact, most animals have both melanin and leucosomes; the melanin causes the animal to be visible, and the leucosomes minimize this effect by scattering light. However, this invisibility is partial invisibility—the animals just become as transparent as physically possible. Xavier: Are there some other future implications for “invisible” human cells other than superpowers? How near in the future is this ability projected to be possible? - There are a number of future implications, in particular for military operations (which is quite possibly a very bad happening). In fact, scientists from the University of Rochester have already created a gadget to aid human invisibility. While this is not necessary the same technology described in this article, a similar logic of minimizing light reflection is at play in this human cell-altering scenario. Given the advancements being made in this field and the general technological growth of the human race, I would give it another 10 to 20 years for this technology to be perfected. Honestly though, who knows? Eric: How successful is invisibility/camouflage as a self-defense mechanism in the wild? What other ways do the example animals protect themselves if invisibility fails to work? - Invisibility is relatively successful as a self-defense mechanism in the wild, especially for aquatic animals such as jellyfish, squid, octopi, and cuttlefish. While some squid create ink clouds to hinder the visibility of predators and buy time to escape, for other species, invisibility is the predominant method of protection; if it fails to work, then these animals will most likely be consumed by predators.
Wooseok: Can individual cells containing reflectin achieve invisibility? (e.g. unicellular organisms) - Given that scientists are modifying individual human cells to achieve partial transparency, I think the answer would be yes. However, the unicellular organism would have to be artificially modified. Hugh: What is the “reflectin A1 isoform?” - The reflectin A1 isoform is a type of reflectin that is able to replicate the growth of human cells due to its optical, electrical, and assembly properties. This protein plays a key role in cephalopod coloration. John: How do the dimensions of the leucosome affect its light-scattering ability? - If by dimensions you mean its ability to self-assemble, then this property of the leucosomes will affect their light-scattering ability through allowing them to modify their photonic architectures to scatter more light in some situations than others.
Works Cited: Chatterjee, A., Cerna Sanchez, J.A., Yamauchi, T. et al. Cephalopod-inspired optical engineering of human cells. Nat Commun 11, 2708 (2020). https://doi.org/10.1038/s41467-020-16151-6 Davis, Nicola, and India Rakusen. “How Cephalopod Cells Could Take Us One Step Closer to Invisibility - Podcast.” The Guardian, Guardian News and Media, 18 June 2020, www.theguardian.com/science/audio/2020/jun/18/how-cephalopod-cells-could-take-us-onestep-closer-to-invisibility-podcast. Lund University. "Skin pigment renders sun's UV radiation harmless using projectiles." ScienceDaily. ScienceDaily, 26 September 2014. <www.sciencedaily.com/releases/2014/09/140926085818.htm>. Siddique, R., Gomard, G. & Hölscher, H. The role of random nanostructures for the omnidirectional anti-reflection properties of the glasswing butterfly. Nat Commun 6, 6909 (2015). https://doi.org/10.1038/ncomms7909
T he Neuroscience of Decision Making: What Lessons Does Dopamine Offer? By ERIC YOON The decisions we make range from those that occur in a split second to ones we delineate for days or even years. It feels natural to us—after all, we’re the ones making the decisions—but taking the time to stop and consider what really happens when we make a difficult choice is a fascinating thought experiment, one individuals have been pondering for millennia. The brain chemistry of how we make decisions is a multilayered process, but looking at the specific chemicals that play a major role can help give us an idea of what to expect. One of these chemicals is dopamine, a neurotransmitter defined in casual speech as the unit of pleasure. It isn’t simply a measure of our pleasure, however: Dopamine is intricately tied with motor and motivational functions, and is vital “for the 'stamping-in' of stimulus–reward and response–reward associations” (Roy A Wise).
Figure 1: Dopamine and serotonin pathways exist throughout the brain, able to be transported in milliseconds. Dopamine is the primary neurotransmitter functioning to control motivation. Source Credit: iflscience.com (L INK) How does this vary for the different types of decisions we make, and what factors influence how much dopamine is released? Amount of time until reward is one, and actual benefit is another.
For the former, an interesting phenomenon arises: the anticipation for a reward often realizes just as much dopamine as when the reward is obtained. Researchers at Paris-Sud University have found that “For the first time, a direct link between DAT availability and reward anticipation was detected within the mesolimbic pathway in healthy and psychiatric participants, and suggests that dopaminergic dysfunction is a common mechanism underlying the alterations of reward processing observed in patients across diagnostic categories'' (Dubol et. al) - dopamine’s primary function serves as a method of anticipation. The reward of anticipation is what motivates us to make decisions. But what changes between different decisions we make and the levels of dopamine released, as well as what factors create the most impact? Besides the actual significance of the decision/reward, the amount of time until the reward arrives is key in determining how much dopamine is released and whether we commit to an action or not. Take the Stanford Marshmallow Experiment as an example of the dilemma: children could take a smaller reward without waiting (a single marshmallow), or receive a larger reward (a second marshmallow) if they were able to successfully wait 15 minutes. Clearly, a larger reward is necessary to justify extra waiting time, and, notably, the children that chose to wait had generally greater “success” in life. What allows us to wait and overcome instant gratification though is the ability of dopamine neurons to learn to encode the long-term value of multiple future rewards with distant rewards discounted.
Figure 2: A second trial of this experiment compared what happened when the marshmallow was exposed vs obscured, finding that the success of the experiment was more pronounced when the marshmallows were open to view while participants waited. Source Credit: Simple Psychology (LINK) That’s what happened in the Stanford Marshmallow Experiment, and why the children who could wait showed a correlation to higher SAT scores and improved BMI: the ability to assign long-term reward values for individual actions is a learned intelligence for the successful achievement of distant goals. Time, practice, and learning all are factors that impact how our body uses dopamine to guide us to make our decisions. Understanding the science is important, then, as sometimes the short-term gains our brain wishes for do not align with the long term benefits we get from results that have delayed gratification. Dopamine holds the potential to understand that, and its lessons have far-reaching applications for our society.
Q&A: Jiwon: In your article, you talk about how dopamine is produced in the process of anticipating a reward, and that time until reward is a factor that affects this dopamine production. How exactly, then, is the amount of dopamine affected by the time until reward? - Sadly, there isn’t a single answer to this question: it depends on the nature of the reward and the importance the brain places on the achievement. The brain’s expectations on how long it will take until a reward is earned is important, however: if the reward comes before, the brain treats it as a pleasant surprise, and dopamine levels increase. If no reward comes by the expected time, dopamines drops. Sally: What about “How does this vary for the different types of decisions we make”? - Decisions that touch on more basic human needs–food, water, and sex, for example– would likely prioritize quick results, as more of the input into those decisions is placed by our amygdala. Decisions that involve more of the prefrontal cortex would likely be able to exhibit more long-term control. The expectations of our brain and subsequent dopamine release would likely reflect that. Xavier: How can this information be applied to high school students’ everyday lives? - My personal takeaways from writing this article was the importance of training your brain to satisfy itself with long-term rewards: for the average high schooler, this could mean studying over playing around, sleeping over binge watching Netflix, etc. Knowing the workings of the brain on what seems to be an intuitive topic helps you be more aware as you make decisions in high school and beyond. Wooseok: How can these studies on the capabilities/functions of dopamine be used to benefit humanity? (Like what are some possible ways in which this knowledge can be utilized? E.g. development of drugs for specific disorders) - Dopamine truly reaches many applications, from resolving psychiatric disorders and drug addictions to optimizing our ability to make smart choices. One that I find most interesting is controlling dopamine release in the aftermath of opioid usage. John: How does DA deficit affect such rewarding mechanisms? - Great question. Individuals with ADHD usually have lower levels of dopamine, which may explain why it’s hard for them to stay on one topic. Works Cited: Berke, J.D. What does dopamine mean?. Nat Neurosci 21, 787–793 (2018). https://doi.org/10.1038/s41593-018-0152-y
Decisions and Desire. 1 Aug. 2014, hbr.org/2006/01/decisions-and-desire. Enomoto, Kazuki et al. “Dopamine neurons learn to encode the long-term value of multiple future rewards.” Proceedings of the National Academy of Sciences of the United States of America vol. 108,37 (2011): 15462-7. doi:10.1073/pnas.1014457108 Eshel, N., Tian, J., Bukwich, M. et al. Dopamine neurons share common response function for reward prediction error. Nat Neurosci 19, 479–486 (2016). https://doi.org/10.1038/nn.4239 Wise, R. Dopamine, learning and motivation. Nat Rev Neurosci 5, 483–494 (2004). https://doi.org/10.1038/nrn1406
The Finale of 2020: the Collapse of the Arecibo Observatory BY HUGH KANG What is, or was, the Arecibo Observatory?
Figure 1: The Gregorian dome was installed as a part of the observatory in 1997. With its two subreflectors and multi-beam receiving capabilities, the Gregorian dome improved the telescope’s ability to focus radiation on specific points in space. However, weighing at over 110 tons, it likely accelerated the demise of the telescope. Source Credit: ScienceMag.com (L INK) The Arecibo Observatory is a 57-year old radio telescope located in Puerto Rico, best known for being the biggest radio dish in the world up until 2016. Curved almost like a bowl, the radio telescope collected naturally occurring radio light from extraterrestrial sources (stars, galaxies, planets) in order to allow astronomers to detect the contours of the surfaces. Originally, the Arecibo Observatory was not intended for astronomers. When it was founded in the early 1960s, the construction was part of a military initiative, with its main purpose being the detection of airborne Soviet missiles. However, as upgrades—such as the installation of aluminum panels that allow detection of higher frequencies—were made, scientists began to
realize that the instrument could be used for far more than what was inside of the Earth’s atmosphere. Instead, it could be used to track asteroids that could threaten the entire planet, rather than just local regions. With targeted engineering towards scientific needs (e.g. installation of radio transmitters and aluminum panels that could collect waves of higher frequencies), the telescope had allowed several significant discoveries in the past decades, including the evidence of gravitational waves, evidence of volcanic repaving on the foggy surface of Venus, and the first-ever planet discovered outside of our solar system. Beyond the pure technological power of the telescope, the Arecibo Observatory was also a cultural icon, with cameos in blockbusters such as Contact and GoldenEye. Puerto Ricans had fully embraced this marvel as the face of their technological innovations, so the collapse had been a painful blow to the citizens. To the local community living in the Arecibo neighborhood, the observatory had been the destination of field trips for many children, helping plant in them an interest in astronomy. How did it fall? https://www.youtube.com/watch?v=b3AASKr_iHc Figure 2: A drone positioned on Tower 4 captures heart-breaking footage of how the Arecibo Observatory collapses. The sequences of suspension cable failure can be observed, starting from the top cable. Source Credit: youtube.com (MDx Media/Arecibo Observatory) (L INK) How did this marvelous, decade-old titan fall? Simply put, the suspension cables broke. But according to Sravani Vaddy, an astronomer at the Arecibo Observatory, the telescope had collapsed spectacularly. On Aug. 10, 2020, the first of the 18 cables had broken, all of which suspended the 900-ton telescope in the air. Three months later, the second support cabled had also disconnected. The National Science Foundation had known about these cables but decided that it would be too dangerous to attempt to repair the giant telescope. As a result, it died a slow, dramatic death, eventually collapsing on the dish on Dec. 1, 2020.
Future implications for astronomy
Figure 3: On December 1, 2020, the 900-ton instrument collapsed, leaving sinkholes in the dish. Source Credit: Nature.com (â&#x20AC;&#x2039;LINKâ&#x20AC;&#x2039;) Despite the shock that was felt by astronomers worldwide, researchers at the observatory have ambitious plans for the reconstruction of the telescope. According to the plan that was submitted to the National Science Foundation, the researchers are looking for a telescope that would have a 300 foot wide platform, more rigid structure, and most importantly, a dish that would contain over one thousand dishes with modern designs. With these plans, the new telescope would have a more powerful beam than the original,double the sensitivity, and quadruple the radar power. It would be named the Next Generation Arecibo Telescope. With such a creation, the researchers will be able to investigate double the original view of the sky and a field of view that is 500 times bigger. Due to the scale of the project, the Next Generation Arecibo Telescope may take years to be constructed. Some have even called it a pipedream. Truly, this represents a time of adversity for the world of astronomy, as well as a moment of opportunity.
Q&A: - Xavier: How exactly does a radio dish function? What information can be derived from studying the surfaces of planets and asteroids? The radio dish functions as a receiver of the naturally occurring waves that are emitted from various objects in outer space. It then uses that information in order to graph out the surfaces of those objects, essentially making the information available for analysis. Great question, so why is astronomy so essential to mankind? Simply put, it allows us to understand the Earth better, as a celestial object in its own right. While we can learn about Earth mostly from our perspective, there are also many things that are simply impossible or difficult to learn from our grounded perspective. Beyond that, understanding space and the place we live in simply helps us answer fundamental questions about our history, and the challenges that we face in exploration has proven to be important triggers in the expansion of technology, new industries, and global peace. Even in our own lives, the first prototype of wireless earphones was created for space exploration. You can credit those AirPods to the astronomers. -
Jiwon: While the Arecibo Observatory had much symbolic value, did it contain any scientific abilities unique to itself? (How is it different from other radio dishes?) The Arecibo Observatory was considered a trailblazer among telescopes. What made it unique was simply its ability to detect emissions that were far more distant than the distances that other telescopes (until it was surpassed by the power of the Five-hundred-metre Aperture Spherical Telescope in 2020). For the past decade, there has been a hunt for fast radio bursts. The Arecibo Telescope immensely aided in this search by discovering that the burst was repeating, indicating that the source of these mysterious radio bursts from space was still present. - Sally: How did they engineer the telescope to make more significant discoveries? As can be seen in the first picture, one of the most notable engineering changes made during the lifetime of the Arecibo Observatory was the installation of the Gregorian Dome in 1996, which contained two subreflectors (which would become the secondary and tertiary reflectors) that would essential assist in focusing the radiation on the space object that it is studying, whether its a planet or star. It also had a horn antenna that would allow a boost in the telescopeâ&#x20AC;&#x2122;s ability to collect these signals. However, unfortunately, many researchers believe that the Gregorian Dome accelerated the fall of the telescope, as it added 300 more tons to the weight that the cables held. -
Wooseok: Why did the radio dish break in the first place? Could this possible factor of downfall be considered in future construction plans? (e.g. lack of care, design issues, etc.) Beyond the weight that the cables had to carry, many of the researchers also suspect that water corrosion may have been a big factor. There was a hurricane in 2017, called Hurricane Maria, that likely accelerated the collapse of the cables. The storm winds carried seawater from the shores onto the telescope, and due to the salt composition of the water, the cables were very vulnerable to corrosion. Scientists are especially considering weather issues in the tropical
climate of Puerto Rico. However, despite the fall, many researchers have reportedly said that the Puerto Rico staff were very caring and scrupulous with the observatory, so they are not to be criticized. -
Eric: What other technologies exist that overlap with the function of a radio dish, and are radio dishes a relic of the past as other technologies advance further? Satellites actually work in a similar way as radio dish telescopes. They use the curved design in order to receive radio signals transmitted from distant objects, while radio dishes capture naturally occurring waves. As satellites are still at the forefront of space exploration, radio dishes are also far from being outdated technology. Even recently, the Chinese government funded the construction of the Five-hundred-meter Aperture Spherical Radio Telescope (FAST) in southern China for over $180 million USD, which is actually the one telescope that has surpassed the Arecibo Observatory in size, prior to its fall. -
John: How can improved government funding towards science help resolve these kind of problems in the future? Good question. One positive aspect of the collapse of the Arecibo Observatory was that it brought many of its discoveries to the public eye again. Hopefully, this event will remind governments of the immense importance of these astronomical instruments and dedicate more funds. Due to the newer and more powerful Five-hundred-meter Aperture Spherical Radio Telescope (FAST) that was constructed in 2020, there are many factors that many lead to the telescope not being constructed, but hopefully we can at least see more government funding in other areas of astronomy.
Works Cited: Australia Telescope National Facility. How Does a Radio Telescope Work?, 17 Nov. 2020, www.atnf.csiro.au/outreach/education/pulseatparkes/radiotelescopeintro.html. Clery, Daniel. “How the Famed Arecibo Telescope Fell—and How It Might Rise Again.” Science, 2021, doi:10.1126/science.abg5640. Eric HandDec. 1, 2020, et al. “Arecibo Telescope Collapses, Ending 57-Year Run.” Science, 3 Dec. 2020, www.sciencemag.org/news/2020/12/arecibo-telescope-collapses-ending-57-year-run.
Gibney, Elizabeth. “Gigantic Chinese Telescope Opens to Astronomers Worldwide.” Nature News, Nature Publishing Group, 24 Sept. 2019,
www.nature.com/articles/d41586-019-02790-3.
Stochastic Gravitational Waves: The Harshly Underrated Sibling of Binary Inspirational Waves BY JOHN K. LEE
Figure 1: A computer simulation of a binary system consisted of two supermassive black holes spiraling into each other. Such a system produces gravitational waves that propagate outwards through spacetime. Source Credit: NASA Goddard Space Flight Center (LINK) Gravitational waves have gained a lot of attention since its first physical observation by the Laser Interferometer Gravitational-wave Observatory (LIGO) detector on Sept. 14, 2015. The ensuing popularization of this observation by the media only spilled gas on the already tempestuous fire. Numerous people were fascinated by this rare astronomical occurrence, which corroborated the belief in both the existence of gravitational waves and binary systems consisting of two merging black holes. Despite the public fascination at this recent observation, gravitational waves are no rare occurrence. In fact, astrophysicists say there are gravitational waves washing over the Earth all the time. The sources of these “stochastic gravitational waves” are yet to be identified, but progress is continually being made. This leads us to the natural question of “what are stochastic gravitational waves?” In order to answer this question, we must first understand the basics, then work up from there. Any high
school student with an interest in physics will have approached the study in the Newtonian formulation. In Newton’s widely applicable (yet fundamentally incorrect) description of gravitation, he describes the phenomenon as the peculiar attraction between any two objects. However, this formulation cannot fully describe what gravitational waves are. A formulation of physics that can accurately describe the phenomenon is that of Albert Einstein. In his theory of general relativity, the existence of gravity hinges on three phenomena: i. Mass bends the fabric of spacetime: that is, the presence of mass distorts the geometry of the 4-dimensional manifold, consisting of three spatial and one temporal dimensions. This distortion increases with mass, but decreases with the distance between an observer and the said mass. ii. This distorted spacetime geometry allows the existence of geodesics that aren’t necessarily straight, but are rather curved. iii. The journey of masses along such geodesics that aren’t necessarily geometrically straight causes masses to naturally gravitate towards each other. Gravitational waves, first predicted by Henri Poincaré, naturally follow this formulation of gravity—they are merely waves (a disturbance in a medium, that propagates outward from its source) that propagate through the very fabric of spacetime, thereby creating disturbances in its geometry. The sources of such gravitational waves are accelerating masses that create ripples in spacetime as they move through it (relative to an inertial frame of reference). This phenomenon is analogous to that of electromagnetic waves (light), in which accelerated charges create disturbances in the electromagnetic field.
Figure 2: The gravitational wave spectrum (from larger periods to smaller periods), their potential sources, and the different mechanisms with which we can detect such gravitational waves. Source Credit: NASA Laser Interferometer Space Antenna (LISA) mission (L INK) Stochastic gravitational waves are relics from the birth of the universe. While its source has not been identified, most astrophysicists theorize that these weak, random, and thus barely detectable gravitational waves that wash over the entire universe—thereby mapping out a cosmic gravitational background—are actually remnants of the gravitational waves created from the random processes generated by the big bang. By detecting such stochastic gravitational waves, we might even be able to map out the story of the early stages of our universe. Some sources from which we can detect such gravitational waves, according to professor Bruce Allen’s “The stochastic gravity-wave background: sources and detection,” are coalescing binary systems, pulsars, and supernovae. A coalescing binary system consists of two celestial bodies (most likely neutron stars or black holes) merging into one. When these objects orbit each other closely, they gravitate to, and spiral into each other due to their immense gravity. As they do so, they create very significant gravitational waves that propagate outwards from the system, like
mallets striking the surface of a drum. As they propagate gravitational waves outwards, the binary system begins to lose angular momentum, thereby spiraling into smaller and smaller orbits, until they merge into one, whereafter the gravitational waves stop propagating. The aforementioned LIGO detection of gravitational waves had its source in such a phenomenon. Pulsars are compact objects (most likely a neutron star) that are highly magnetized and rotate at very fast rates. These pulsars emit stable and periodic radio waves/pulses whose timing we can very precisely predict from Earth. Thus, if gravitational waves were to interrupt the path of a radio beam headed towards Earth, its path would bend, and its timing will be erratic, thereby giving us clues about such gravitational waves. Lastly, a supernova is an explosion that occurs during the death of a star - as the nuclear fuel of the star runs to depletion, the star, unable to withstand its own gravity, collapses unto itself, crushing even its constituent atoms, and thereafter creating a powerful explosion, during which great gravitational waves are generated. In comparison to detecting the gravitational waves generated by the merging of two celestial bodies, detecting stochastic gravitational waves are analogous to trying to distinguish the sound of a conversation in a boisterous party, due to its comparatively minute magnitude. For the past several years, interferometer technology, such as the LIGO and VIRGO detectors (alongside the less-known geo-600 and tama-300) and numerous radio telescopes have been put into use in order to detect such waves. A newer technology called Laser Interferometer Space Antenna, consisting of interferometer technology in outer space (with three spacecraft situated in a triangular manner following a heliocentric orbit) is currently under development. Furthermore, recent reports show that the North American Nanohertz Observatory for Gravitational Waves (otherwise known as the NANOGrav Institute), a leading force in using radio telescopes to observe pulsars and detect gravitational waves, has successfully received some strong signals that hint at gravitational waves from an unknown source. There is still much work to be done, and the detection of stochastic gravitational waves is a ripe frontier of exploration.
Q&A: - Xavier: What would the confirmation of these stochastic gravitational waves mean? Why are they important? - By mapping out the stochastic gravitational wave background, we will be able to map out how the universe evolved after its creation. - Jiwon: In your article, you mentioned that astrophysicists say that gravitational waves are a continuous occurrence. Then, why is it taking so much time to detect and analyze these waves? - This is mainly because gravitational force is the weakest of the four fundamental forces of nature. Thus, perturbations in the gravitational field are barely felt by any detector. Moreover, gravitational waves come in various wavelengths. The technology we have at the moment can detect gravitational waves of small ranges of wavelength (and this is partly why we want LISA and pulsar timing array technologies - to detect waves of different wavelengths). - Sally: What are some other potential sources of stochastic gravitational force since you mentioned in the beginning that the sources are yet to be identified? - Here is a comprehensive list of the possible sources of stochastic gravitational waves: - The Big Bang, Binary systems (of black holes, white dwarves, and neutron stars), Neutron Star spin, Compact stellar masses spiraling into black holes, Supernovae. - Wooseok: Do these gravitational waves have significant impacts on human life? (e.g. health conditions) - The answer is no. While the gravitational waves stretch spacetime, they do it at such small scales that it is barely felt or heard by humans. - Josh: How could the analysis of stochastic gravitational waves help in future space exploration? - â&#x20AC;&#x153;By mapping out the stochastic gravitational wave background, we will be able to map out how the universe evolved after its creation.â&#x20AC;? This means that we will be able to gather more information about the properties of celestial bodies. - Eric: What threshold of mass do neutron stars/black holes need to be to generate gravitational waves? As long as any size combines, are gravitational waves produced? - Yes - as long as anything has mass, it has an effect on gravity. Analogously to large binary systems, if you and I were to dance around each other (or really accelerate in any fashion), we would create gravitational waves (though very minute in amplitude). - Hugh: What does the 3 point about the theory of general relativity outline in the essay? Perhaps you can connect back to it later in the essay? - The 3 points about the theory of general relativity are the propositions from which we can hypothesize (and confirm) the existence of gravitational waves.
Works Cited: “'Galaxy-Sized' Observatory Sees Potential Hints of Gravitational Waves.” ScienceDaily, ScienceDaily, 11 Jan. 2021, www.sciencedaily.com/releases/2021/01/210111125614.htm. Allen, B. “Sources and Detection.” CERN Document Server, 17 Apr. 1996, cds.cern.ch/record/301296?ln=en. Cofield, Calla. “What Are Pulsars?” Space.com, Space, 22 Apr. 2016, www.space.com/32661-pulsars.html. Garner, Rob. “NASA's Goddard Space Flight Center.” NASA, NASA, 10 Feb. 2015, www.nasa.gov/goddard. Hensley, Kerry. “Can We Detect Gravitational Waves from Core-Collapse Supernovae?” AAS Nova, 5 July 2019, aasnova.org/2019/07/05/can-we-detect-gravitational-waves-from-core-collapse-supernova e/. “Introduction to LIGO &amp; Gravitational Waves.” LIGO Scientific Collaboration - The Science of LSC Research, www.ligo.org/science/GW-Stochastic.php. “LISA - Laser Interferometer Space Antenna -NASA Home Page.” NASA, NASA, lisa.nasa.gov/. North American Nanohertz Observatory for Gravitational Waves, nanograv.org/. “What Is LIGO?” Caltech, www.ligo.caltech.edu/page/what-is-ligo.
Will flying green be possible with hybrid-electric planes? BY SUNMIN LEE
Figure 1: MIT’s new hybrid-electric plane design with the emissions control system. Source Credit: MIT(L INK) Air transport is responsible for two to three percent of global carbon dioxide emissions, and has also contributed to the steady increase in other air pollutants such as nitrogen oxides and sulfur dioxide. In the United States, aircrafts emission has increased 17 percent since 1990, and without further advancements in environmental friendly aviation technology, researchers estimate a 43 percent rise in NO emissions by 2035. And, of course, these statistics reflect devastating consequences. Ten thousand people die every year due to airplane exhaust, which cause cardiovascular and respiratory diseases and infections. With growing concern over the effects of air travel pollutants, research upon improving aviation technology has increased significantly in recent years. An emerging technology is the Hybrid Electric Propulsion System (HEPS), which combines conventional combustion engines with an electrically-fueled method. In order to effectively integrate and reduce the possibility of failure, many studies have developed energy management
strategies, such as various configurations and system designs. In addition, newly discovered advancements have been included as Harmon et al. from the University of California-Davis did by applying the concept of neural network control to the system to optimize energy efficiency. For small-scale, mid-scale, and large-scale aircrafts, researchers developed distinct strategies, each having certain advantages and disadvantages, and their respective maximum payload, seats, and flight time varied. Despite the fact that they had made an arduous effort, it seems very challenging for them to create feasible designs. MIT, however, revealed that their hybrid-electric plane design has no significant fundamental physics limitations compared to previous studies, and that its system is quite viable with the addition of another concept called the emissions control systems, a setup that filters the exhaust. While researching the Volkswagen emissions cheating scandalâ&#x20AC;&#x201D;an incident in 2015 of car manufacturers turning on the emissions control systems only during lab testing to merely pass the NO emission standardâ&#x20AC;&#x201D;they became interested in the emission control systems and how they are used in diesel trucks to eliminate nitrogen oxide emissions. Combining the idea with hybrid electric propulsion seemed to provide two environmental advantages: reduction in use of fossil fuels and less harmful chemical released from exhaust. However, in current aircrafts, jet engines are beneath each wing with a gas turbine that is directly connected with the propeller. Due to the fact that their exhaust is pushed out to the back of the aircraft, MIT engineers could not attach the emissions control systems for they would significantly block the thrust produced. As a solution to this problem, the team suggested placing the gas turbines in the plane cargo hold. Then, instead of them directly powering the propellers, would drive a generator, which would also be repositioned in the cargo hold. Now, applying hybrid propulsion, specifically in the form of series configurations, the electricity produced from the generators would power the propellers or the fans. The emissions control system will also be located in the cargo hold, and the exhaust from the turbine would be filtered without issues. MIT revealed that this newly developed system can reduce the amount of NO emissions by 95 percent and possibly contribute to the decrease in associated diseases and early deaths by 92 percent. Not only does HEPS help reduce pollution, but it can help sustain natural resources with its use of electricity. Indeed, a total electric system is more favorable in terms of being eco friendly, but there is a reason for this semi-electrified plan: battery weight. Compared to a volume of fuel that can provide the same amount of energy, the electric motors require batteries that are 30 times heavier. For small planes flying a short distance, this implementation might be possible, but for large planes that need to carry passengers as well as the batteries, they might have problems taking off due to its weight. However, with ongoing developments in battery technology, it will not be long until this system will be finalized, allowing us to fly green.
Q&A: - Jiwon: You briefly mentioned the Volkswagen’s emissions cheating scandal. For what reason did the scientists only turn on the emissions control system during lab testing, and what exact environmental impacts did this action have? - They only turned on the system to meet the NO emission standard, and after testing, the cars emitted 40 times more NO than it did during testing. - Xavier: The only downside seems to be a constraint regarding the weight hybrid-electric planes can carry. Are there no other obstacles preventing the possibility of flying green? - The design is finalized, but the plane is not actually produced, so there might be other challenges, but for now, the only problem explained is the weight.
Works Cited: “How Hybrid Electric and Fuel Aircraft Could Green Air Travel.” Horizon,
horizon-magazine.eu/article/how-hybrid-electric-and-fuel-aircraft-could-green-air-travel.ht ml.
“Hybrid Electric Aircraft: State of the Art and Key Electrical System Challenges.” IEEE Transportation Electrification Community,
tec.ieee.org/newsletter/september-2016/hybrid-electric-aircraft-state-of-the-art-and-key-ele ctrical-system-challenges. Jennifer Chu | MIT News Office. “Concept for a Hybrid-Electric Plane May Reduce Aviation's Air Pollution Problem.” MIT News | Massachusetts Institute of Technology, news.mit.edu/2021/hybrid-electric-plane-pollution-0114. Zart, Nicolas. “This Hybrid Airplane Could Become the Tesla of the Skies in the Next Two Years.” Robb Report, Robb Report, 7 May 2020, robbreport.com/motors/aviation/hybrid-electric-airplane-rewrite-aviation-two-years-29193 73/. flydragon/Depositphotos, and Mit. “MIT's Hybrid Electric Plane Concept Captures Its Own Harmful Pollutants.” New Atlas, 19 Jan. 2021, newatlas.com/aircraft/mits-hybrid-electric-plane-concept-pollutants/.
How are autoimmune responses related to the coronavirus? BY WOOSEOK KIM
Figure 1: Artificially colored coronaviruses under an electron microscope Source Credit: Fred Hutchinson Cancer Research Center (L INK) The clear atmosphere that seems deceptively empty is in fact bursting with all sorts of harmful microorganisms, ready to invade the human body at all times. While millions of these foreign invaders infiltrate our systems at every moment, a significant portion of the attempts are rendered obsolete thanks to the immune system, a set of lymphocytes dedicated for the purpose of identifying and removing harmful antigens from the body. However, as odd as it may sound, these loyal defenders sometimes strike down their own allies, a phenomenon that scientists refer to as “autoimmune responses.” Possible causes that lead to autoimmune responses can mainly be divided into four categories: genetic, hormonal, environmental, and infectious. Autoimmune responses are caused by a variety of different components, with examples ranging from the failure of specific gene expressions to heavy exposure of ultraviolet rays, and even affliction of certain diseases like the Human Immunodeficiency Virus. While autoimmune responses could be categorized in numerous ways depending on their distinct causes and consequences, a shared aspect among all types is the activation of defect immune cells that misidentify normal host cells as sources of danger, eradicating them like how they would do so against foreign pathogens. This deliberate act of self-harm not only damages organs, but also impairs the existing immune system, thus
weakening the body and making it more vulnerable to outside forces. Common examples of diseases resulting from autoimmune responses include arthritis, type one diabetes, and sclerosis. While these autoimmune responses generally tend to be caused by internal factors of the human body, they could also come to be as a byproduct of infections caused by external antigens, as stated previously. Like the Human Immunodeficiency Virus, Researchers have recently discovered that the COVID-19 virus may have close connections with autoimmune responses. A key symptom of COVID-19 is that it triggers the body to release an abnormally large amount of cytokines, a type of hormone that initiates the immune response against pathogens. Cytokines are regulatory hormones that mark the transition from an innate immune response to an adaptive immune response, initializing the CD4 Helper T Cells which in turn allows the activation of Plasma B Cells and CD8 Cytotoxic T Cells. While an appropriate amount of cytokines is necessary in order to empower the immune system, an excessive amount can deregulate the immune system and trigger autoimmune responses. Scientists have named this phenomenon of excess cytokine production as the â&#x20AC;&#x153;cytokine storm syndromeâ&#x20AC;?. Rather than simply activating a greater number of immune cells for longer periods of time, the cytokine storm syndrome is also accompanied by the loss of control over the activated immune cells, preventing the immune system from recognizing healthy cells as harmful pathogens and proceeding to assault them. This indiscriminate attack damages and causes inflammatory responses in multiple sections of the body. However, this phenomenon also hints at the possibility of utilizing autoimmune disease drugs to alleviate symptoms displayed by patients of COVID-19. As the main problem at hand is the increased degree of inflammation that takes place all over the body, a key consequence of the cytokine storm syndrome, scientists project that taking medication that reduces the production of cytokine, and thus preventing the over activation of the immune system, could potentially lessen the critical effects of COVID-19. As much as how COVID-19 has shown to instigate various critical autoimmune responses and related disorders, such as arthritis and the Guillain-BarrĂŠ syndrome, multiple researchers have also proven that immunomodulatory drugs like cytokine blockers and inflammation reducing drugs like glucocorticoids are effective at assuaging the viral infection cases.
Q&A: - Sally: Is the autoimmune response the only explanation for the symptoms of the coronavirus? What are some other assumptions? - Xavier: Have scientists begun developing medication that could counteract the overactivation of the immune system mentioned in the final paragraph? - Yes! There are existing medications that combat the overactivation of the immune system, most of which involve immune-suppressing hormones such as cytokine blockers and glucocorticoids. - Jiwon: How are these immunomodulatory and inflammation reducing drugs effective in countering infection cases? In other words, what is the mechanism behind how they work? - Like how their names suggest, immunomodulatory drugs function by suppressing unnecessary immune activation responses. Thus, it could be said that they are effective against infection cases only when there is an excessive immune reaction. - Eric: How do autoimmune responses differ between the different types of coronavirus? - Josh: Are there any ways through which autoimmune diseases can be preemptively treated? Is there a way in which we can reduce the risk of developing autoimmune disorders, like how we prevent infection through vaccines? - John: What are the socio economic implications of these findings? How can they help alleviate the effects of the current pandemic? Are the side effects of the cytokine inhibitor drugs (some of which are increased susceptibility to pathogens) a logical payoff for dulling the effects of coronavirus on the immune system? - These findings not only provide temporary solutions to some, but also help the development of future medications to combat the current COVID pandemic. - Hugh: I feel like you can add more about the even more broader picture of what this means for the pandemic. How certain are we that immunomodulatory drugs are a sustainable, affordable, and practice solution to the virus? Works Cited: Ehrenfeld, Michael, et al. "Covid-19 and Autoimmunity." Autoimmunity Reviews, vol. 19, no. 8, Aug. 2020, p. 102597. ncbi, doi:10.1016/j.autrev.2020.102597. Accessed 30 Jan. 2021. Novelli, Lucia, et al. "The JANUS of Chronic Inflammatory and Autoimmune Diseases Onset during COVID-19 – a Systematic Review of the Literature." Journal of Autoimmunity, vol. 117, Feb. 2021, p. 102592. ScienceDirect, doi:10.1016/j.jaut.2020.102592. Accessed 30 Jan. 2021. Shoenfeld, Yehuda, and David A. Isenberg. "The Mosaic of Autoimmunity." Immunology Today, vol. 10, no. 4, Apr. 1989, pp. 123-26.
ScienceDirect, doi:10.1016/0167-5699(89)90245-4. Accessed 30 Jan. 2021.
Why stem cell research is being conducted in space BY XAVIER KIM
Figure 1: Astronaut Peggy Whitson adjusts a microscope used to observe the growth of MSCs aboard the International Space Station’s laboratory module. Source Credit: NASA (LINK) Modern medical research has surpassed the domains of Earth to space, and for good reason. The conditions in space allow scientific experimentation without the influence of gravity, making certain types of research more accessible and effective. More specifically, experiments aboard the International Space Station (ISS) since its launch in 1998 have provided new, impactful insight into human health here on Earth. In particular, stem cell research has been an integral part of the ISS’s mission, and researchers believe that a breakthrough is close. In 2017, Abba C. Zubair, the Director of Transfusion Medicine and Stem Cell Therapy at the Mayo Clinic collaborated with NASA to explore the growth of human-derived mesenchymal stem cells (MSCs) in an ISS laboratory. Their goal was to verify the “feasibility, potency, and safety” (Nature) of space-grown stem cells for clinical procedures both on Earth and in long-term spaceflight. MSCs are valuable due to their importance in tissue repair and regeneration as it is able to differentiate into a variety of cells, including osteocytes (cells found in bone),
chondrocytes (cells found in cartilage), and adipocytes (cells found in connective tissue within the skin). Moreover, another crucial function of MSCs is their ability to release cytokines and other growth factors that catalyze the production of other stem cells such as neural, skeletal, and hematopoietic stem cells, which regenerate blood cells. The research done by Zubair is significant as it tests the growth of stem cells in microgravity. Stem cell research on Earth faces limitations as the regular, two-dimensional cell culture does not accurately simulate the environment of human bodies in which stem cells typically develop. While cells in this setting can grow outwards, they are unable to grow upwards or downwards. Furthermore, it can also be observed that these cells are constantly in contact with the plastic or glass that contains them during experiments, thereby making them only able to organize themselves into simple, single-layered structures. Conditions on the ISS, on the other hand, eliminate these constraints, and stem cells are able to grow in three dimensions, forming complex aggregates. The results of the investigation, which were published in June 2020, concluded with the final findings of the experiment. Microgravity not only promoted MSC secretion of cytokines and growth factors but also found that the stem cells grown in space were more immunosuppressive than their Earth counterparts. All in all, they determined that MSCs grown in space can safely have clinical applications. The result of the experiment has several critical implications in both the scientific fields of space exploration and medicine. Further research of stem cells in space could improve the safety of astronauts in long-term space missions. Astronauts in the ISS are subject to an average of ten times more cosmic radiation than people on Earth. The environment in space can have negative effects on human health, just as it did for NASA astronaut, Scott Kelly. After spending a year on the ISS, his body was met with a number of repercussions: fluid-swollen upper body and head, unusual gene activation, an overactive immune system, inflammation in his microbiomes, and even a loss of cognitive ability. If space agencies like NASA intend to follow through with their ambitions requiring long-term spaceflight and even moon colonization, they will have to keep the health of every crew member a priority. As such, the ability to readily treat astronauts through regenerative therapy utilizing stem cells will be essential to further space exploration. In a global population that continues to grow older, age-induced conditions like stroke, cancer, and dementia are affecting a growing number of people. As organ transplant procedures are the most effective remedy, the necessity for organ donors is proportionately rising. However, the demand for such organs is much too overwhelming relative to the limited supply. Moreover, organ transplants through donors face the risk of rejection, as the human body only accepts compatible organs. Fortunately, further research on stem cells will allow doctors to close this gap. The ability to grow tissues and entire organs in space could allow patientsâ&#x20AC;&#x2122; own cells to be
used, lowering the possibility of rejection. Stem cells will, without question, prove themselves to be a critical component of tissue engineering. If it were not for the laboratories available in microgravity conditions, stem cell research would have reached a roadblock long ago. The laboratories in Earthâ&#x20AC;&#x2122;s orbit provide a new medium for scientists to test the limits of medical research, and to apply their findings back on Earthâ&#x20AC;&#x2122;s surface. Within these experiments, stem cell research, in particular, will undoubtedly continue to be a major point of focus for scientists and astronomers alike to make the next breakthrough discoveries in their proper fields.
Q&A: - Sally: Is there a way to imitate outer space condition? - While it is possible to emulate microgravity here on Earth, it is only in short periods of time. The ISS allows longer durations of experiments to observe long term effects of microgravity. - Jiwon: Why is the ability of MSCs to release growth factors that catalyze the production of other stem cells important? What will happen to a human body without enough of these MSCs? - Found in the bone marrow, MSCs are stem cells that are imperative to both the production and maintenance of skeletal tissue. These specific kinds of stem cells are also important as they are multipotent, meaning they can differentiate into many different types of cells. - Wooseok: Are there any significant side effects to conducting this research in outer space? - Eric: How have the previous ways stem cells were extracted (from fetuses) contributed to the push for research? - Josh: What are some current limitations in advancing stem cell research in space? - One obstacle in this effort will definitely be a time constraint, as the ISS is planning to close by the year 2024. The eventual shutdown of the ISS will be a big blow to a large range of sciences as its laboratory in microgravity has provided many breakthroughs in its twenty years of orbit. - John: Do the potential health benefits justify the economic resources required to sustain this process? - There is definitely a good reason to invest large sums of money into this research. It has benefits that can be realized both within Earth as well as in outer space, such as the growth of human tissues in space. - Hugh: How does the fact that these cells were â&#x20AC;&#x2DC;immunosuppressiveâ&#x20AC;&#x2122; and /form complex aggregatesâ&#x20AC;&#x2122; allow their applications in space exploration and medicine? You do draw the connection in the article but you should also go back to why your explanation at the start is able to be used in these applications.
Works Cited: “Cutting-Edge Biomanufacturing Aboard the International Space Station.” NASA, NASA, science.nasa.gov/science-news/news-articles/3d-biomanufacturing-aboard-the-ISS. Huang, P., Russell, A.L., Lefavor, R. et al. Feasibility, potency, and safety of growing human mesenchymal stem cells in space for clinical application. npj Microgravity 6, 16 (2020). https://doi.org/10.1038/s41526-020-0106-z Johnson, Michael. “20 Breakthroughs from 20 Years of Science Aboard the ISS.” NASA, NASA, 26 Oct. 2020, www.nasa.gov/mission_pages/station/research/news/iss-20-years-20-breakthroughs. “Microgravity Tissue Engineering Could Help Deep Space Crews Regrow Human Body Parts.” Thomasnet® - Product Sourcing and Supplier Discovery Platform - Find North American Manufacturers, Suppliers and Industrial Companies, Thomasnet, www.thomasnet.com/insights/microgravity-tissue-engineering-could-help-deep-space-cre ws-regrow-human-body-parts/. “Studying Stem Cells in Space for the Benefit of Humankind on Earth and Beyond.” ISS US National Laboratory, 11 June 2020, www.issnationallab.org/blog/stem-cell-research-results-published-zubair/#:~:text=The%2 0investigation%20established%20the%20feasibility,to%20survive%20better%20in%20m icrogravity.