Issue 2 Spring 2015
Behind Also In This Issue:
The People and the Processes That Make Science Happen
Understanding Our Animal Friends Let’s Talk About Sex (and Parenthood) The Mystery of Alzheimer’s Disease & Three Sets of Clues Explosive Water
Table of Contents Welcome to Inscripto: Letter from the Editor..........................................3 The Creation of Gods: Why we anthropomorphize.................................4 A scientist’s best friend.......................................................................................6 Let’s Talk Bird Brains.............................................................................................8 Baby-Crazy: The Mind-Control of Motherhood...................................... 10 What We Talk About When We Talk About Sex....................................... 12 Does Fat Play A Role In The Development of Alzheimer’s Disease?.15 How to Rebuild a Brain.................................................................................... 18 The Mystery of Alzheimer’s: is it an Autoimmune Disorder?............. 20 The Case for Basic Science Research.......................................................... 23 The Blind Eye of Objectivity........................................................................... 25 Recap: The Atlanta Science Festival............................................................ 28 Staying in Touch................................................................................................. 30 Under-representation in research............................................................... 32 Towards Precision Medicine: Promises and Hurdles............................. 34 Explosive Elements: *Just add Water* ....................................................... 36 Solar Water Splitting: Future Paths to Clean Unlimited Energy..... 38
The Science Writers Association of Emory Editor-in-Chief
Marika Wieliczko B Wilson
Jadiel Wasson Kristen Thomas
Welcome to Inscripto: Letter from the Editor
ello everyone, and welcome to the Spring 2015 Issue of Inscripto. My name’s Anzar Abbas and I’m a PhD student in the Neuroscience Program at Emory. I was approached last fall by Yun Wei, a fellow graduate student, to restart an old student organization called the Science Writers Association of Emory. It was an effort made by past graduate students to write about science in a way that would be interesting to the public. Unfortunately, as those students graduated, SWAE dissolved as well. Yun was able to drum up interest for the group from just enough people, and we embarked upon a mission to recover and relaunch SWAE and its publication, Inscripto. It’s been a challenge, but I’m glad to say we’re finally getting on our feet. The spring Issue of Inscripto has twice as many contributors than the fall, and we’re proud to launch all of those insightful articles on our brand new website so they’re even easier to read and share amongst your friends. SWAE’s aim is to provide an opportunity for students at Emory – particularly those working in the STEM fields – to participate in the popular communication of science. They are welcome to write about current issues in their field, topics of public interest, and even their own research. It’s an exercise that hopes to foster a generation of scientists that are better connected to the public, and play a more central role in the delivery of scientific knowledge to the masses. We hope to do this partly through Inscripto, which aims to provide a comfortable introduction for a scientist to the world of popular science communication. I thank everyone that chose to contribute to the spring 2015 issue of Inscripto, especially those who were embarking upon popular science writing for the first time. Most of all, I invite all others to ponder the possibility of contributing as well. Sure, it’s a bit of effort and time. But it easily redeems itself in lessons and an appreciation of the difficulty of explaining complex ideas simply. There is beauty in communicating science in layman’s terms. Lastly, this publication could not have been possible without every bit of effort from our entire team. I want to thank Brindar Sandhu, our Managing Editor, for her leadership and work in producing this issue, along with our wonderful Associate Editors, B Wilson and Marika Wieliczko. Responsible for the impeccable design behind the text on every page are our talented Design Editors, Kristen Thomas and Jadiel Wasson. If you aren’t reading this in print, you must be reading it online, and for that I would like to thank Sara List for countless hours towards the development of SWAE and Inscripto’s website. Hope you enjoy the issue! Until next time Anzar Abbas Editor-in-Chief
The Creation of Gods:
Why we anthropomorphize
ave you ever assigned human-like traits to animals or even inanimate objects? If so, you’ve participated in something called anthropomorphism. We often attribute emotions to animals and intentionality to mindless objects. Every time you mistake your coat-rack for an intruder or claim that your puppy loves you, you are guilty of anthropomorphizing. Anthropomorphism is the tendency to assign human traits such as physical qualities, emotions, intentions or thoughts to non-human objects such as animals or objects.
when we observe others performing an action. People with deficits in the regions where these mirror neurons are located correspond to deficits in empathy and Theory of Mind. Unsurprisingly, these are the same regions of the brain that are active when a person is anthropomorphizing. Predicting the actions of animals and inanimate objects employs the same brain regions as predicting the behavior of another human. Though we can consciously differentiate between human and non-human, the same mechanisms in our brain are activated when we are observing actions of both.
Humans naturally treat everything as if it possesses some degree of understanding or responsibility. (Have you ever cursed at your printer or encouraged your car to start?) This is a byproduct of our tendency to anthropomorphize. It permeates our perception. It is a commonality in human life, and one that can be particularly problematic given the right circumstances.
It is important to note that the way we experience our thoughts is not just constrained by our perception, but by the language we have available to communicate our perception. Think about it this way: Most people would agree that a mouse cannot think like a human. At the very least, you can probably agree that you cannot tell what a mouse is thinking. To know what a mouse is thinking you would either have to be a mouse or be able to talk to a mouse. So how do we explain mouse behaviors? What is a mouse doing if not thinking? We don’t have a word for it. To fall into my own trap, we can’t think like a mouse, so we have no words to describe what may be happening inside a mouse’s head. We’re forced to imagine things like only a human can because after all, we are only humans.
But why do we anthropomorphize?
Long story short: it’s the way we’re naturally wired. Human brains are tuned to try to understand other human’s intentions, thoughts and feelings. This concept is called Theory of Mind. Specific regions of the brain contain populations of ‘mirror’ neurons, which display the same activity when we’re performing an action as
So what’s the use of anthropomorphism? It’s quite easy to justify why we would want to understand other humans. We’re a social species, and thus need to be able to comprehend others to at least some degree. But is anthropomorphism just a byproduct of an overenthusiastic brain trying to give Theory of Mind to everything? Doubtful. Evolutionarily speaking, it is almost always better to assume something is smarter than it is. More accurately, it is almost always better to assume that the something is out to get you and that the something is intelligent enough to fear it. Believing every shadowy figure is a robber is much safer than believing every shadowy figure is a bathrobe. Believing every spider is full of malicious hate for mankind is safer than not giving any spider a second thought. Think of your anthropomorphic brain as a highly sophisticated better safe than sorry mechanism. We’re programmed to believe, at least initially, that everything we see behaving is behaving with some degree of intentionality. The results of this can be good or bad.
What are the consequences of anthropomorphism? As mentioned above, anthropomorphism is usually a good thing. But when can anthropomorphizing go awry? Dr. Shannon Gourley, a professor of Neuroscience at Emory University, describes anthropomorphism as “a dual threat.” She says, “we run the risk of trivializing the human condition. Can a mouse really experience the debilitating nature of schizophrenia? Of autism? We just don’t know. And the related issue pertains to the limits of our ability as scientists to interpret our data. If we attribute human-like traits to an animal, we run the risk of failing to consider other possibilities. For example, is the mouse huddled in the corner because it is “depressed,” or because it’s simply cold? Or ill?”
directly translatable to common human experiences. However, Dr. Gourley reminds us that “reporting that the mouse develops ‘depression-like’ behaviors is more scientifically accurate -- and it allows us to bear in mind the alternative possibilities, and to acknowledge the limitations of our own knowledge which are bound by the fundamental inability to directly communicate with animals.” Our brain’s predisposition for giving agency leads us to see intention, thought, and cause in the natural world, even when it is not explainable. We naturally attribute intentionality to everything we see: whether it has a human brain, an animal brain, or no brain at all. Anthropomorphism is so prevalent that some biologists and biological philosophers claim that it is the basis for people’s perception of higher powers, or gods, acting on the world. When thinking about deities, the same brain regions within the brain are active as when attributing Theory of Mind to other humans. Since the beginning of time, humans have been attributing unexplainable events to entities that they cannot see or feel, only sense and infer. Some scientists claim the neurological basis for anthropomorphizing contributes to this phenomenon. In essence, we could even be constructing ideas of gods in the image of ourselves.
Even despite the risks, it is not uncommon to hear a meteorologist to talk about the wrath of nature or a biologist to talk about what a cell wants to do. It is especially tempting to anthropomorphize when research appears
A scientist’s best friend
the biology behind the human-dog relationship Kristen Blanchard
f you had visited Tokyo’s Shibuya Station in the 1920s, chances are, you would have met Hachikō. At the end of every day, this purebred Akita Inu faithfully waited for the train to deliver his master, Hidesaburō Ueno. Yet, when Ueno died in May 1925, Hachikō continued to wait. For the rest of Hachikō’s life (nine years, nine months, and fifteen days to be exact), Hachikō continued to arrive at the station and wait for his owner’s train. Hachikō may be the most famous symbol of canine loyalty, but he is by no means alone. Capitán, a German Shepherd in Argentina, stayed with his owner’s grave for 6 years after he passed. Orlando, a black lab guide dog in New York City, helped save his owner from an oncoming subway train after the man fell onto the tracks. In addition to these “celebrity” dogs, we rely on countless others to help us track missing persons, locate explosives, and help those with disabilities. In return for their services, we love these creatures like no other on the planet. More than one third of American households own a dog, and we spend more than $50 billion annually on our pets. It seems obvious that dogs are man’s best friend, but why does the bond between man and dog seem so much stronger than with any other animal? The answer to this question likely lies in dogs’ unique history. Domesticated dogs, as we know and love
them today, evolved from ancient wolves. Unlike the evolution of virtually every other animal species throughout history, the evolution of dogs was artificial. Humans essentially “created” this species by domesticating wolves. Through lucky accidents in different regions throughout the planet, ancient humans noticed that some wolves were more cooperative than their peers. They took in these unusually helpful wolves, cooperating to hunt prey and avoid predators. Biologists believe that by continually selecting for better companions, wolves and humans evolved side-by-side, eventually creating the unique bond between modern humans and dogs. This strong evolutionary pressure has had significant consequences for the way humans and dogs interact. In the past few decades, scientists have been able to quantify what dog lovers have long understood on an intuitive level; the bond between canines and humans is unique among the animal kingdom. Scientists have demonstrated that dogs are adept at communicating with humans. They can pick up on auditory cues and even physical signals. Dogs understand the meaning behind human pointing, while even our closest relatives, great apes, cannot interpret this gesture. Despite the fact that great apes are more intelligent than dogs, and more closely related to humans, dogs are better at com-
municating with us. This communication skill goes beyond merely communicating basic information. Some evidence shows that dogs can understand human emotion. Scientists at the University of Veterinary Medicine in Vienna, Austria tested dogs for their ability to recognize human facial expressions. The study found that dogs could distinguish between “happy” human faces and “angry” human faces, even while only seeing part of the face in a photograph. What do dogs do with this information about human emotion? Do they “care” if a human is happy or angry? Do dogs have some sort of empathy with their human companions? Scientists have recently tried to answer these questions as well. Contagious yawning (i.e., the tendency to yawn when witnessing someone else yawn) is thought to be a sign of empathy. Contagious yawning is usually more common between people who are emotionally close, than between strangers. Scientists at The University of Tokyo recently investigated whether dogs were also affected by the contagious yawning phenomenon. They found that not only did dogs exhibit contagious yawning when seeing humans yawn; this effect was also more common between the dog and its owner than the dog and a stranger. These results suggest that dogs do display this measure of empathy. The idea that dogs possess empathy for their human companions is further supported by an interesting study by researchers at the University of Otago in New Zealand. These scientists measured the human physiological response to a baby crying. Humans respond to this trigger with an increase in cortisol and heightened alertness. Fascinatingly, they discovered that a human baby crying affected dogs in the same way. In addition to the increase in cortisol and heightened alertness, dogs also became more submissive. While it is difficult to quantify whether or not dogs “love” their human companions, there is certainly some evidence that dogs have empathy for humans and an understanding of human emotion.
to be in dogs? Some recent studies suggest that this evolution was a two-way street; just as dogs evolved to cooperate better with us, we evolved to cooperate better with them. While dogs are adept at recognizing human facial expressions, we are adept at recognizing theirs as well. A recent study found that even people without any experience with dogs were able to infer a dog’s emotion from a photograph. The fact that even those without dog experience were able to complete this task suggests that this recognition may be innate – an artifact from our co-evolution with domesticated dogs. Fortunately for us, while dogs may have influenced our evolution, it seems to be worth the tradeoff. Our relationship with dogs provides us numerous benefits as a species. Dogs have a well-documented effect of reducing stress. The American Heart Association has even reviewed the scientific literature and agreed that dog ownership may slightly reduce the risk of heart disease. These health benefits explain why dogs are frequently used as therapeutic aids – they can help soldiers recover from trauma and help children with autism improve their social skills. Thanks to our truly unique interspecies bond, these creatures really are man’s best friend.
We’d like to thank the Atlanta Humane Society for allowing us to photograph the dogs featured in this artlcle. To adopt your new best friend, check out atlantahumane.org.
But what about the other side of this relationship? It certainly seems as though humans’ artificial selection of ancient wolves contributed to the way dogs relate to humans today. Were humans also affected by this parallel evolution? Is the bond between humans and dogs hard-wired into us the way it seems
Let’s Talk Bird Brains Zack Johnson
For a long time we thought that language separated us from other animals, but it’s a bit more complicated than that. Chimpanzees, bonobos, gorillas, and orangutans can all learn sign language. Dogs can use body language, vocalizations, and even facial expression to communicate; and many birds can sing extraordinarily intricate songs to relay information. Even insects and plants can release chemicals that carry important information to their neighbors. So what’s unique about language? While many animals can “speak,” or produce sounds, humans are uncommon because we can imitate sounds and mix and match them in new combinations to communicate information. This process is called “vocal learning,” and it requires using our vocal chords to imitate sounds. Neuroscientists believe we can do this because we have unique connections in our brains between higher processing areas at the front and motor areas further back that control our vocal chords; other primates—which can’t do vocal learning—don’t have these connections. But humans aren’t the only vocal learning animals, and
scientists have turned their attention across 300 million years of evolution to learn more about this unique capacity. While many birds can sing, their songs are often innate and fixed. Only three lineages possess the unique ability to learn, imitate, and modify their vocalizations based on what they hear: parrots, hummingbirds, and songbirds. Neuroscientists discovered that, like humans, these birds also have unique connections between frontal areas and motor areas controlling the vocal chords. These connections are absent in birds that can’t do vocal learning, like chickens. Both humans and vocal-learning birds that suffer damage to these connections have trouble imitating others’ vocalizations and stringing syllables together correctly. These discoveries had scientists scratching their heads: not only can distantly related birds do vocal learning, but their brains seem to be doing it in a similar way. Before diving deeper, it’s important to appreciate the explosion in technological capacity that biologi-
cal research has witnessed in the past few decades. In 1950, we didn’t know what DNA was. Since then we’ve learned that the genetic codes, or “genomes,” of both humans and birds are made of billions of nucleotides (the “N” in DNA). We know that every cell in the body contains the same genetic code, but specific kinds of cells turn parts of the genome “on” or “off,” depending on their jobs. Think of pianos; they all have the same 88 keys, but pressing those keys in different combinations and to different degrees results in different chords. Different types of cells in our bodies “express” different combinations of genes and to different degrees; each type has its own “chord,” or its own unique gene expression fingerprint. This is even true across species: gene expression fingerprints of skin, heart, and brain cells in humans may look different from each other, but they look very similar to gene expression fingerprints of skin, heart, and brain cells in other animals. A team of Duke neuroscientists led by Dr. Erich Jarvis recently took these ideas a bit further: are the gene expression fingerprints of “vocal-learning” brain cells unique? In other words, maybe the animal genetic code can express certain genes to create vocallearning brain cells across species, just like skin cells or heart cells. The scientists collected tiny samples of bird brain tissue from vocal-learning brain areas in parrots, hummingbirds, and songbirds and analyzed the gene expression fingerprints for each. Next, they tapped into a huge database of gene expression
fingerprints spanning the entire human brain. Like forensic detectives, they searched the database for matches. Sure enough, the strongest matches in the human brain database were regions involved in human speech and language. So what? The idea here is that perhaps we aren’t quite as unique as we’d like to think. Scientists have known for a while that the genes guiding human body development are the same exact genes guiding body development across fishes, amphibians, reptiles, and birds. The Duke neuroscientists extended that idea to specific capacities of the human brain. The same genes that guide the development and wiring of areas involved in human vocal learning also guide the development and wiring of areas that control vocal learning in birds. This is important because our language capacity is a huge part of being human, and it has indisputably shaped the course of our history. As biology advances, we will certainly continue to learn more about this unique capacity from parrots, hummingbirds, and songbirds, as well as our other vocal-learning relatives: bats, seals, elephants, and dolphins. In the meantime, the next time someone calls you “bird brain,” consider it a compliment, and take a moment to wonder what other capacities of the human brain and mind might be hidden in the animal genetic code.
The Mind-Contro of Motherhood
Amielle Moreno Introduction
The Power of Hormones
Any wilderness expert will tell you the most dangerous animal to see in the wild is a baby bear. Accidently stumbling between a mother bear and her cubs is a sure way to get mauled. And none of us would be here today if it wasn’t for the selflessness of our ancestors, sometimes putting the survival of their offspring before themselves.
I’m sorry to be the one to tell you this, but the areas of your brain responsible for decision-making can be overpowered by hormone-driven signals from deeper brain regions. During development, hormones influence the structure of our bodies, including our brains. During puberty, the same hormones can act again on these existing systems to make you feel awkward during gym class. But perhaps the largest natural shift in hormone concentrations is during pregnancy.
So apparently, the most basic drive for self-preservation can be trumped by babies. While we can’t live forever, we can pass on our genes. Thus, what Richard Dawkins termed “selfish genes” have created animals built for their own survival, and that drive for self-preservation can be redirected to reproduction and then parental care.
The milieu of hormones pregnant women experience can make long-lasting structural changes to the neurons in our brain. The neurons in deep brain regions responsible for maternal behavior can grow in size when exposed to pregnancy hormones such
as estrogens. So, the same time motherhood occurs, the brain is experiencing significant changes. The growing neurons start to communicate with areas of the brain that make the signaling molecule dopamine. Dopamine rules what neuroscientists call “the reward pathway” and it’s the reason you like anything… ever… in your entire life. Your body releases this magical molecule when you perform activities that will keep you and your genes alive and spreading. Dopamine is released while consuming food or having sex, and because your genes want to be passed on, the drive for parental care relies on this reward pathway too. Large doses of estrogen, such as those occurring during late stages of pregnancy and labor trigger the release of dopamine, stimulating the reward system. This makes new mothers primed and ready to love that 7 pound 5 ounce screaming, floppy pile of responsibility, you named “Aden.” Hormones lead to new and permanent changes in brain circuitry, which is how areas of the brain interact and respond to one another’s activity. Perhaps surprisingly, animals that haven’t been around babies are not initially fond of infants. Virgin, pupinexperienced female mice have a natural avoidance to infant stimuli, which is not completely unreasonable. Think about what a baby would seem like if you didn’t know what it was: they cry for seemingly no reason, smell, and demand a lot of time, money and attention. In mice, researchers have explored a natural avoidance and defensive response associated with animals that are new to infant care. There are defined circuits in the brain responsible for this avoidance response. The hormones of pregnancy, silence this circuit, and neural circuits responsible for maternal responses can then be more active.
Changes in Behavior You might have heard from your friendly neighborhood neuroscientist that you don’t have free will. Let me reassure you that yes, you’re a slave to the power of babies. The immediate changes in a mom’s behavior after childbirth suggest major changes
are occurring in brain circuitry. This new baby addiction or “sensitization” is caused by changes in the reward system’s dopamine release. Cocaine and other addictive drugs trigger the reward system and release dopamine throughout the brain. Like a drug, the allure of babies is so strong that when given the choice, rats with maternal experience prefer to press a lever that delivers infant pups over one that delivers cocaine. Using this knowledge, let’s take care of two societal problems at once: “Orphanages: The New Methadone Clinic!” Sensitization causes mothers to act differently. Mother rodents show increases in risk-taking behavior. For example, mother mice on an elevated maze with enclosed and open arms, will spend more time exploring the potentially dangerous open arms than virgin mice. On the up side, new mothers display increases in memory. In a maze, mother rats were better than virgins at remembering where the food was and were faster to retrieve it. The researchers concluded that improved foraging memory increases the chance of survival for a mother’s pups. If this held true in humans, the concept of “baby brain” might be unfounded. However, funding cuts have halted the construction of the human-sized maze stocked with baby supplies. Even abstaining from motherhood won’t save you from becoming a slave to baby overlords. Mere exposure to infants can activate changes in the brain regions responsible for maternal behavior, and start the process of sensitization in rodents. The process does take more exposure time than in natural mothers, without the surge of hormones to speed things along. This suggests that women become “baby crazy” by exposure to infant stimuli. While we all might inherently be ambivalent or avoidant of infants, through exposure to them, babes become conditioned and highly rewarding stimuli. Do you want kids? Then it might already be too late. Not being female won’t save you either. A study that looked at brain activity using an fMRI machine found that when fathers are shown images of their children, they display similar brain activity as mothers. Recent research out of Emory made headlines when it found this increase in activity in the reward
pathway was inversely correlated with testes size, and blood testosterone concentration. The conclusion: more parental care equals less testosterone and smaller balls, fellas!
Against Logic The combination of a higher consciousness and a desire to reproduce means, unlike other animals, humans are presented with the question of if we should reproduce. However, the reason they instruct you on airplanes to put the air mask on yourself before you assist young children is because the human drive to protect our genes, I mean, children, sometimes overrides logic. There’s also an illogical drive to have our own children. In a planet with millions of
orphan children, you would assume that the baby-loving masses (and cocaine addicts) would decrease the supply of foster kids overnight. However, our biological nature has a way of convincing humans that we don’t just want a child, but we want our child. In a modern environment where motherhood is a choice, it’s illogical for anyone to be pressured to give birth to an eighteen-year commitment. Because not all people (or laboratory animals) naturally become sensitized to infants, it might be better for everyone if people who don’t want children aren’t pressured to have them. By simply understanding the literally mind-altering process of parenthood, individuals can make decisions that benefit everyone, including our baby overlords.
What We Talk About When We Talk About Sex Edward Quach
he manner in which societies and cultures have constructed gender and gender identity has been changing for ages. Although an academic or philosophical dichotomy was not acknowledged for several thousand years, the separation of physiology and gender identity has existed perhaps since the dawn of man. It may have its origins in the very moment early hominids forewent stark individualism and entered into John Locke’s social contract. A couple days ago, I had the opportunity to chat with the John L. Loeb Associate Professor of the Social Sciences at Harvard University, Sarah Richardson. Dr. Richardson is a historian and philosopher of science with an impressive collection of research concerning gender and the social dimensions of science. Ac-
cording to Dr. Richardson, the academic sex/gender distinction is traced to the 1960s and sexologists dealing with gender identity disorders or feminist theorists of the same era. Nonetheless, she goes on to trace less specific philosophical sparks of this distinction to the 19th century and earlier. As we can see, for several decades now, social scientists have been studying countless aspects of gender. The sociology, psychology, history, politics, and performance of gender have been under scrutiny in humanities classrooms around the world. However, one thing that has seemed to remain relatively static is the biological understanding of “sex”, a steadfast counterpart to the fluid and constructed idea of
gender. Or so it was presumed. Growing up in the in the fairly progressive time period that I did, my childhood had been at least minimally shaped by the idea that a person’s gender may not actually match up with what they have between their legs. That being said, it was fairly well established that your sex was your sex, and that the distinction was primarily binary (male or female). However, a recent Nature News feature published by Claire Ainsworth examines several studies both new and old, which may complicate the issue of biological sex in the way that the social sciences have unpacked and examined gender. According to Ainsworth, the binary male vs female distinction is antiquated, and biology requires a more comprehensive spectrum. When I asked Dr. Richardson about this, she elaborated on the concept, explaining how a hard-line distinction between the biological sexes was often an underpinning of more traditionalist ideologies which use this dimorphism to reinforce restrictive gender roles. She feels it is “important to really allow the scientific data to speak for itself and to learn from the great degree of variation…” But what are these data and wherein lies the variation? We have all heard about individuals born without physiologically distinct male and female parts. In the medical field they are referred to as individuals suffering from Disorders of Sex Development, or DSD, but you might have heard the term “intersex”. These individuals, while not entirely uncommon (some form of DSD occurs in approximately 1% of individuals), are likely not going to rewrite government and medical forms or completely change the way we understand sex. Besides, the fact that many of you will recognize the term “intersex” implies that this condition (or set of conditions) is something that isn’t outside the realm of general knowledge. A lot of us are already aware of intersex individuals, but we’ve yet to adjust our concept of biological sex. A more broad-scale change in our attitudes toward biological sex may require a more radical challenge. Coincidentally, there are some interesting cellular and molecular events that may give us a little more food for thought. Take, for example, the axiom that human males have one X and one Y sex chromo-
some in their cells while females have two X chromosomes. This is one of the most universally accepted facts about biological sex, especially among nonscientists. You don’t have to have a degree in a life science to know that this difference in our chromosomes makes us male or female. In the case of this guiding principle of biological sex, there is a good basis for it. It is true in general that if you snatch a single cell from anywhere in my body and look at the chromosomes, you’ll see one X and one Y. However, in the case of the merging of twin embryos, there can be individuals born with some cells bearing an XX and some bearing an XY. Indeed, given certain circumstances of this chimerism as we call it, one may not even notice that they are living with two distinct groups of cells in their body. Certainly in the case of would-be twins that fuse in the womb, this is an interesting phenomenon. However, chimerism in humans is not so rare. There are a number of much more common processes by which we can acquire the cells of another genetically distinct individual and grow with that person’s cells becoming, quite literally, a part of us. Consider the significant interchanges that can occur between mother and fetus during gestation. These exchanges of materials can and often do include cells, specifically stem cells which are multipotent or pluripotent, a term we use to mean that they can turn into many different kinds of cells. We call this phenomenon microchimerism, and it means that you can have cells from your mother inside of your body right now. In fact, if you have any older siblings, it is possible that their cells continued to grow in your mother’s body, and were subsequently transferred to your body during your growth. I can sense the outcry from younger siblings already. These cells are not just mooching off your energy, either. In many cases, they are earning their keep by working. Cells from your mother or siblings may mature into cardiac tissue, neurons, immune cells, and the like, lending a whole new meaning to the term “you’ve got your mother’s eyes”. In addition to actually having cells in your body from another person of a different sex, there are instances where the sex differences may be even sneakier. For decades, scientists believed that sex development was a pretty clean switch from female to male, with female being the default program. It was thought that the female programming had to be suppressed
by the male programming in order for genes responsible for testes, male sex hormones, and other sex characteristics to win out. However, more recent studies have identified a signal for testicular development which female programming must suppress in order for feminine characteristics to develop. Development of one sex over the other (although expressing them in a binary appears to be getting harder and harder) is not one program overriding the default program. Rather, it is a constant competition of factors. There isn’t just one “yes” or “no”, but rather a chorus of “yes” and “no” shouting in a cacophony that may well come out sounding like a “maybe”. When I first began researching this issue, these phenomena all seemed like fun or intriguing biological quirks. I thought it was fascinating that some people could be born with genitals not matching their chromosomes or with a cellular makeup that was a mosaic of male and female. However, I began to wonder what these new understandings meant for us as a country, a society, and a species. One issue, which Ainsworth and many before her have highlighted, is the common practice of genital “normalization” procedures that occur quite frequently. They allow intersex babies to go on and develop as one sex or the other. We have come a long way in our societal treatment of gender. Many people no longer care what pronouns you use to refer to yourself, your choice of sexual partner, and the way you choose to dress. If I am being too optimistic about this, then there are at least signs of progress in that direction. On the other hand, there are no such advances being made in the world of medicine and biological sex. Babies are too young to be able to consent to this change in their genitals, often occurring just days or hours after birth. Do parents have the rights to decide which sex their intersex child
continues down the path of? Is this in the same vein as trying to change someone’s sexuality or gender identity? Richards was quick to emphasize that there are clear differences between gential normalization procedures and something like gay conversion therapy. Nevertheless, she underscored that a healthier way to approach this kind of surgery would be to ensure it is coming from a place of informed and empirical science, perhaps for individuals who are old enough to understand what is unique about their bodies, and not out of our sense of panic that intersex does not conform to the binary. Another issue may arise in individuals with chimerisms, which may describe many of us. There are certain diseases, both genetic and acquired, which affect one sex (or perhaps I should say “chromosomal profile”?) more severely than the other. Let’s say that certain cells in my brain developed from my mother’s cells which I acquired in the womb. If I were suffering from a brain disease affecting XX individuals more severely than XY individuals, doctors might not necessarily diagnose me correctly until they had exhausted many other options, simply because I’d checked M on the form in the waiting room. It would appear that the issue of sex development and biological sex has not quite reached a critical mass, but this growing body of work certainly complicates sex in ways we could not have anticipated during the development of our medical system and our societal opinions on sex. While pressure to adhere to a given gender is beginning to alleviate, pressure to conform to a single, specific sex is alive and well. It can be a little discomforting to think so differently about a concept we often consider black and white, but understanding the intricacies which govern sex development can help us to appreciate the beauty of gray.
There isn’t just one “yes” or “no”, but rather a chorus of “yes” and “no” shouting in a cacophony that may well come out sounding like a “maybe”. 14
Does Fat Play A Role In The Development of Alzheimer’s Disease?
ue to the growing prevalence of Alzheimer’s disease and limited efficacy of drugs for the associated memory-loss symptoms, scientists and non-scientists alike are interested in the potential for practical lifestyle changes such as diet to reduce the risk of developing Alzheimer’s disease and memory loss. The food you eat can alter the chances you and your loved ones will develop diseases such as Alzheimer’s or dementia. Yet even if you’ve merely dipped your toe into the vast ocean of information
on nutrition and Alzheimer’s disease, it’s easy to become confused about which foods or food-types you should add to or remove from your diet if you want to reduce your risk of developing Alzheimer’s disease. Unlike the protective effect of some foods, such as leafy green vegetables, the role of fat and fatty foods in Alzheimer’s disease risk seems to be less understood, and controversial. What is clear is that its role in Alzheimer’s disease is a little complicated. Luckily, despite the present uncertainty about
whether some types of fats or specific fatty foods fatty foods are actually beneficial or harmful, the research on diets and Alzheimer’s disease risk does seem to coalesce around some common themes that can be translated into real-life changes. What seems most certain is that not all fats are created equal.
Which fatty foods should I avoid? Red meat & Dairy.
Consumption of saturated fats – including those found in red meats and high fat dairy – has been linked to lower cognitive performance in healthy elderly people, as well as increased risk of developing dementia or being diagnosed with Alzheimer’s disease. Saturated fat intake may increase Alzheimer’s disease risk or exacerbate cognitive decline by degrading the integrity of the blood brain barrier (which usually protects the brain from potentially harmful agents in the blood), increasing inflammation in the brain, or decreasing the ability of brain regions important for memory to use glucose for energy. Saturated fats also increase cholesterol, which is involved in the regulation of the beta-amyloid proteins that are thought to play a major role in driving the disease process. In short, you may want to hold off on the cheese burgers.
Which fatty foods should I eat? Fatty Fish.
Several epidemiological studies have found that the more people report consuming fatty fish, the less likely they are to develop cognitive impairments and be diagnosed with Alzheimer’s disease or dementia. The “fattiness” of the fish is likely key to the protective benefit, as the consumption of lean fish has been linked to an increased risk of developing dementia. It also seems likely that the particular fat is found in fish, mainly polyunsaturated fats that are rich in Omega-3 Fatty Acids, may play a role in keeping the neurons in your brain healthy and communicating effectively.
Indeed, positive results from clinical trials with just Omega-3 Fatty Acids supplements corroborate the role of these fatty acids in improving cognition – or at least slowing cognitive decline in healthy elderly and Alzheimer’s disease patients. Studies in animals have found that Omega-3 Fatty Acids may also prevent Alzheimer’s disease by enabling the synthesis of Acetylcholine, a neurochemical important for attention and memory that is drastically reduced in the brains of Alzheimer’s disease patients. Omega-3 Fatty Acids may also promote the clearance of some of the pathological proteins (e.g. beta-amyloid) that likely drive the disease process. However, the benefits of eating fatty fish may go beyond their fattiness: fatty fish are also a rich source of minerals that may protect against oxidative stress that occurs during aging and Alzheimer’s disease. For example, sardines contain high levels of Selenium, a mineral with antioxidant properties that is decreased in Alzheimer’s disease patients. To reap some of these promising benefits, pile your plate high with fatty fish such as salmon, sardines, and mackerel.
Which fatty foods should I be cautious about? Coconut Oil.
Excitement over the health benefits of coconut oil seems to have taken the internet world by storm. It’s purported role in Alzheimer’s disease is largely driven by the testimony of one physician who reported that giving her husband coconut oil actually reversed his Alzheimer’s disease symptoms. However, coconut oil specifically has not been linked to Alzheimer’s disease risk in epidemiological studies, and there seem to be no clinical trials that have systematically evaluated the effects of coconut oil. In animal studies, some have found beneficial effects on cholesterol levels (e.g. less of the “bad” LDL cholesterol) and cognition, whereas others report harmful effects on cholesterol levels and cognition. There could be many reasons for these inconsistencies, but one possibility is that the optimal amount of dietary coconut oil to consume in order to ward off dementia lies within a narrow range.
...a mere tablespoon of coconut oil has 12g of saturated fat
Indeed, a mere tablespoon of coconut oil has 12g of saturated fat – which is over half of your recommended daily intake. So what is driving all the hype? The saturated fat in coconut oil mostly consists of medium-chain-triglycerides, which may not be as harmful as the long-chain-triglycerides found in cow milk, for example. In fact, medium-chaintriglycerides are converted into ketones, which serve as an alternative energy source for the neurons in your brain. This could be especially helpful in Alzheimer’s disease, as the neural and cognitive dysfunction may be partly due to the decreased ability of Alzheimer’s disease brains to properly metabolize and use the primary energy source of the brain, glucose. Even more promising, some studies have also found that ketones may be able to protect neurons from beta-amyloid and its associated attacks on neuronal function. Nevertheless, you may want to restrain from dousing your food in coconut oil until scientifically-rigorous research has time to catch up to the enthusiastic anecdotes that can be found on the internet. In the meantime, coconut oil in low amounts is probably a good alternative to butter and margarine, but only in those recipes in which a rich source of Omega-3 Fatty Acids – such as olive oil – simply will not do. An important caveat to remember is that your genetic background can play an important role in the efficacy of nutritional interventions. For example, many nutritional correlations or interventions show
no effect or even an opposite effect in carriers of the APOε4 allele, a gene that codes for a protein involved in blood cholesterol transport. It may be worthwhile, then, to find out whether you or your loved one is a carrier before implementing any dietary change to lower your Alzheimer’s disease risk. Another important thing to remember is that Alzheimer’s disease normally occurs late in life, when the nutritional status and dietary patterns reflect decades of habits of eating. Not to mention other lifestyle habits – such as physical activity levels or coping with stress – that may synergistically or antagonistically interact with your diet to affect your overall risk. That is, it may not be possible to reverse 70 years of cheeseburgers with 2 years of sardines. All things considered, it is very unlikely that we will find a secret, super-diet that will protect us all from Alzheimer’s disease and dementia. If anything, dietary changes are more likely to delay the onset, decrease the speed of cognitive decline, or otherwise lessen the severity of Alzheimer’s disease in subtle ways. However, given the limited treatment options for Alzheimer’s disease, incorporating a few relatively inexpensive and tasty diet changes is worthwhile. Especially when a particular diet or food has other known benefits – such as reducing your risk of developing diabetes and heart disease or promoting healthy weight loss – what do you have to lose?
How to Rebuild a Brain
Hibernating animals perform a truly remarkable feat every winter. First, their body temperatures cool to within a few degrees of ambient temperatures, well below what humans can survive. Arctic ground squirrels allow their core temperature to drop below the freezing point of water. Their brain activity also becomes almost undetectable: only the regions required for maintaining vital functions like breathing
remain active. The brain shrinks as neurons retract their branches and lose spines, the leaflike protrusions where they receive signals from neighboring neurons. In humans, hypothermia causes an almost complete loss of spines, like trees in the dead of winter. In hibernating animals, however, only a quarter are lost, so it’s more like the thinning of the leaves in early fall. Upon waking from hibernation, the neurons return to their original size within two hours. Imagine watching the plants grow in the spring but on fastforward. Though the neurons may not regain their original shape exactly, hibernator brains regain all of the size and complexity they possessed prior to the loss. When neuronal loss of this extent happens in the brains of Alzheimer’s disease patients, the damage is irreversible: our brains are not naturally capable of such large-scale recovery. But what if we can mimic the brains of hibernators? Mild hypothermia has long been known to be protective in neurodegenerative disease, but until recently we had no idea why. Early this year, re-
Photo by Alan Vernon
ithin your brain lies a forest of treelike cells called neurons. Each has elaborate branches and even small leaflike protrusions. When you are young, these cells slowly grow to form intricate networks that remain with only minor changes throughout your lifetime. Unless they don’t. Sometimes the leaves fall, the branches retract, and the progress of growth gets turned on its head and into its ugly nemesis: neurodegeneration. In patients with Alzheimer’s disease, this process is irreversible. Yet in hibernating mammals, like bears and ground squirrels, this process occurs every winter and is rapidly reversed in the spring. Research suggests that these animals may hold the key to treating neurodegenerative disease.
Nature may have already provided a solution for Alzheimer’s disease...
searchers reported that cooling the brain causes it to produce cold shock proteins. One of these, called RBM3, can start the process of making new proteins on a massive scale. This allows the cells to rebuild themselves and to recover from the damage caused by cooling. This process of cooling and recovery appears to have beneficial longterm consequences: even brief bouts of hypothermia can delay the onset of neurodegeneration in mouse models of Alzheimer’s disease. Future therapies might increase RBM3 in patients’ brains to delay the beginning of symptoms, including memory loss, and to promote brain recovery from damage that has already begun. The hibernating brain might also provide insight into a hallmark of Alzheimer’s disease: paired helical filaments. Though they sound innocuous, these filaments of protein are thought to wreak havoc on brain function. When a common brain protein called tau gets modified with negatively charged phosphate groups, the modified tau, or hyperphosphorylated tau, can form these filaments within cells and impair function. Hibernating brains, however, contain large amounts of hyperphosphorylated-tau, particularly in the regions where neurons shrink the most. Upon awakening, the brain clears it com-
pletely. We don’t know why this phosphorylated tau accumulates in the hibernating brain, what function it serves, or how it is cleared. Answering these questions in hibernators will help us understand Alzheimer’s disease and perhaps lead to new disease treatments. Millions of Americans currently suffer from Alzheimer’s disease, and that number will only continue to rise as long as our population ages and science searches for a cure. As the trees bloom this spring and these animals awaken from their winter slumbers, they are redefining what we think is possible in brain regeneration. Nature may have already provided a solution for Alzheimer’s disease in the resilient brains of ground squirrels and other hibernators, but before we accept it one lingering question remains. When hibernators’ neurons regrow, how closely do they resemble their previous form? The shapes and connections of neurons hold our memories, our personalities, and even our identities. What if they take on a new shape completely? Perhaps the squirrel that lies down in the winter is not exactly the same squirrel that rises in the spring. When the alternative is Alzheimer’s disease, how much should we care?
THE MYSTERY OF ALZHEIMER’S: IS IT AN AUTOIMMUNE DISORDER? Kevin Sullivan There is a good chance that you personally know someone suffering from Alzheimer’s disease. This is unsurprising, as it is estimated that one out of every nine people over 65 is affected, making it the most common form of dementia. Initially, someone with Alzheimer’s will show signs of forgetfulness and disorientation which may not be immediately noticeable. A person might find themselves losing their keys more often or asking the same question multiple times in a conversation without realizing it. These symptoms gradually get worse over a period of three to nine years, leading to more severe memory loss, mental and physical impairment, and eventually resulting in death. According to the 2014 World Alzheimer Report, 44 million people are living with dementia worldwide, with the number set to double by 2030. Aside from the devastating emotional costs imposed upon the individuals and their care providers, usually family members, the economic impact of dementia is an imposing figure. In 2010, the cost of care for dementia was $604 billion, with costs expected to exceed $1 trillion by 2030. Decades of research have revealed several risk factors for the disease, such as age, head trauma, heart disease, and sex (women may be more susceptible than men). Despite information about these risk factors and studies revealing the differences between the brains of people with Alzheimer’s relative to those of healthy people, the exact cause still remains a mystery. In recent years, researchers have discovered many clues that have gotten us closer to solving this mystery. One of the key findings is that the degeneration of the brain in Alzheimer’s is associated with the presence of protein fragments called amyloid beta peptides. Amyloid beta is present in healthy brains as well, but problems arise in Alzheimer’s when these peptides become folded in an incorrect way, causing them to associate with one another and form clumps, called plaques, which deposit in the brain.
Another major finding is that tau proteins, which normally help to stabilize the structural components of cells, can become defective in Alzheimer’s disease, causing them to get tangled up and deposit in the brain. Both amyloid beta plaques and tau protein tangles are quite toxic to nerve cells and eventually result in the death of the neurons that make up the brain. Despite these and a variety of other clues that have been discovered, Alzheimer’s is plagued by the classic chicken-or-egg question: which of the observed problems are causes of the disease, and which ones are a result of the disease process? So far, this question has been very difficult to answer. Only one form of Alzheimer’s, known as early onset familial Alzheimer’s disease, has a definite cause involving a mutation in specific genes that produce amyloid beta proteins. However, these mutations are the cause of only 1 to 5 percent of cases, while the origin of the rest of the cases remains unclear. The field of Alzheimer’s research is rapidly advancing, with new discoveries made nearly every day. One intriguing recent discovery suggests that an immune response may be responsible for the progression of Alzheimer’s disease. In a March 2015 review published in Nature Immunology, a group led by Michael T. Heneka from the University of Bonn explained some of these recent findings. One of these hypotheses proposed explains that, because amyloid beta is found in several different viruses and bacteria, the body developed an immune system response to the peptide in order to fight off these pathogens. In some cases, the immune response can become misdirected and targets the amyloid beta found in human tissue instead of that of an invader, which is known as an autoimmune response. When the immune system attacks tissue within the brain, it causes damage to the local neurons and leads to destruction of brain tissue. The immune response in the brain is controlled by cells called microglia. These cells act as the guard
dogs of the central nervous system, both defending against infections and scavenging damaged cells and waste found around the brain. Much like certain dogs, they can have extremely strong reactions to even small disturbances. This sensitivity, while quite advantageous for quickly responding to threats, can also have major consequences if they become so sensitive that they start attacking human tissues. Once the microglia are activated, they release molecules that trigger inflammation in surrounding tissue. Inflammation is a process that normally helps to eliminate the initial cause of an injury and help with tissue repair, but persistent inflammation will result in significant cellular damage. Moreover, this response actually makes it more difficult for the body to clear beta amyloid plaques, causing a negative feedback loop that results in even more plaque deposition in the brain. Adding more evidence to this theory, a new study published in the Journal of Alzheimer’s Disease on February 2015 by the Bieberich lab at Georgia Regents University demonstrated that an autoimmune response might be responsible for the progression of the disease. Researchers have discovered that a molecule called ceramide, mainly found in membranes surrounding cells throughout the body, can be targeted by the immune system. This immune response causes an increase in antibodies that destroy ceramide in the brain. The research-
ers found that when amyloid beta plaques start to build up in the brain, certain cells begin producing more ceramide. The ceramide is then targeted by the immune system, causing inflammation and increasing the amount of amyloid beta in the brain. These new studies suggest that our own immune response, then, may be what is ultimately responsible for the advancement of the disease. While we may still not know the root cause behind the mystery of Alzheimer’s disease, these new findings have revealed another important clue, which is that autoimmune responses may play a significant role in the progression of the disease. One of the exciting aspects of this research is that it opens up a whole new set of opportunities to treat Alzheimer’s using therapeutics that target the microglia or reduce inflammation in the brain, which may be able to slow down the progression of the disease. More effective treatments are sure to significantly address the mounting healthcare costs associated with the growing population afflicted with this disease. More importantly, these new treatments have the potential to provide life-altering relief to those currently suffering from Alzheimer’s.
Behind the Science Pages 22-33
The Case for Basic Science Research Brindar Sandhu
ow many times have you been asked to donate $1 for juvenile diabetes, cancer, ALS, MS, or Alzheimer’s research at the grocery store checkout? What about space exploration, how bacteria fight infections, or the basis of all life? Chances are pretty high that you’ve been asked the former, and about zero that you’ve been asked the latter. We know why – diseases pull at people’s heartstrings. We most likely all know someone, or know someone who knew someone, who has had cancer. We want to cure diseases; that’s why we study biology. Obviously we’re not in it for the money or the fame. Does this mean that everyone should solely study a cure for some disease? Is it wrong to be motivated by wanting to learn more about the world we live in? A poll conducted by the winners of a 2013 video competition sponsored by FASEB, the Federation of American Societies for Experimental Biology, asked the general public of San Francisco the following question: If you had $10 to spend on research, would you donate to researching affordable diabetes treatment, or to study how bacteria protect themselves? The public overwhelmingly chose diabetes, but in the 1960s, the National Institutes of health, or NIH, chose the latter. By doing so, scientists discovered that bacteria produce restriction enzymes to cut up foreign DNA. Now almost every lab uses restriction enzymes for cloning. Not just that, but this discovery allowed scientists to clone human insulin - which was previously only purified from cattle and pigs or chemically synthesized with poor yields - and express it and purify it from bacteria. The bacterium used, E. coli, quickly earned the nickname “the laboratory workhorse.” This dramatically reduced the cost of insulin for those suffering from diabetes, and today, almost all diabetic people use recombinant human insulin instead of animal insulin. Anyone who has written a grant application for the NIH knows that the proposed research has to have a translational impetus. “Why should I care?” is a question we are taught to answer. We are required to provide evidence as to what contribution our research will make. If the answer is “We don’t
know how this will benefit medicine, energy, or technology...yet,” does that mean it shouldn’t be pursued? A survey of the research laboratories in the Graduate Division of Biological and Biomedical Sciences, or GDBBS, here at Emory, shows that about two-thirds of faculty research descriptions contain a specific type of disease, drug development, or the word disease. That number is most likely lower than the actual percentage of labs that focus on the disease state. I am not arguing that studying the disease state is not fruitful. Of course we need to know how a disease operates if we ever want to treat or even cure it. I argue, however, that sometimes the solution can be answered in a way that would not be obvious if we solely focused our efforts on curing cancer. Studying how nature works in a non-disease state can tell us a lot about how nature stays healthy, and thus, how we can stay healthy. If the stigma surrounding basic science research is prominent among scientists, how can we expect the public, and therefore, the federal government, to support such important endeavors? “But so much more is known about biology than 60 years ago,” one could argue. Does this mean we have learned all we need to know? Of course not. Yes, biology has had an explosion of knowledge in the last half century, but people still suffer from disease, even if they are different than the ones we saw 100 years ago. We also know that cancer is a lot more complicated than we originally thought, and the reality of a cure-all cancer drug is now just a figment of our imaginations. Although we have learned a lot in the last 60 years, much is clearly unknown, and focusing solely on diseases can limit our ability to find solutions that could be applied to multiple problems. Most scientific advancements, especially technological ones, are based off of how nature operates, so further exploration into how nature works in general, not necessarily in the disease state, is crucial for scientific advancement.
The Blind Eye of Objectivity Sara List
cientists must take daily snapshots of our work, recording what we see one piece at a time. The full picture is too vast for the lens. The fisheye would distort the image if we included too much, too many variables with too few controls. We want to capture the world as it really is, and in order to do so with our limited frames of view, we use objectivity as our guide. Scientific objectivity refers to the idea of recording only those phenomena that are observable without prejudice or bias. The use for such an approach is vast in the world of science but also limited. SScience seeks to categorize, to filter, and to quantify observations. When we conduct science, we try to leave our social, political, and experiential backgrounds behind in favor of the ideal of pure logic. This practice does allow us to make compelling arguments when trying to convince others that our findings, not those of others, are reflections of the truth. â€ŻIf someone is open-minded toward having one set of results and another for their experiment, then he or she does not have any reason outside of
the merit of the experiment itself to have obtained those results. Striving for scientific objectivity can seem noble, chivalrous even. The knights of research lay down their beliefs, their emotions, their political contentions, and their self-serving motives all in the name of science. However, thereâ€™s one practical problem with this ideal. People who are completely disinterested in an experiment or science in general are often also indifferent about it. These people cannot be paid to do research, given how much effort is required. Those who are paid to do science then, are a passionate and opinionated few. There are multiple potential threats to scientific objectivity which can include one or a combination of the following desires on the part of the scientist: desire for approval, desire for potential financial gain, and to avoid controversy. In addition, active advocacy for a certain public policy or vested interest in a particular theory can cloud the objective lens as well. These factors can and do interfere with the
scientific approach if ignored by the research community. However, in addition to our scientific enthusiasm, many of us also depend on outside agencies to fuel our work, and the funding can be contingent upon those agencies’ approval of our research. The quest for scientific objectivity may be a noble one, but that quest adds more problems than solutions to the ever-morphing body of knowledge we call modern science.
was a prominent scientist who strove for leaving his personal opinions out in favor of the facts, he also had clear goals to use craniometry to “find some information relevant to the intellectual value of the various human races.” With this hypothesis in mind, he concluded that “In general, the brain is larger in the mature adult than in the elderly, in men than in women, in eminent men than in men of mediocre talent, in superior races than in inferior races.”
Striving to be the omniscient, neutral observer can lead us into territory that only leaves us blind to our own biases. Neuroscience in particular is rife with examples of social bias motivating how we study the brain, even though, or perhaps because, objectivity is the goal. The study of the brain, and by extension, the human mind, gives particular sensitivity to the findings. Scientific objectivity lends scientists a certain authority. That authority is never clearer than when examined within the world of brain science. With that power comes the responsibility to be aware of our human subjectivity.
The case of Broca is a shocking example of scientific objectivity clouding the inner skeptic. He may have thought that by striving for scientific objectivity, he was immune to being subjective. Broca did not question the premise that craniometry could illustrate differences in intelligence. Instead, he designed experiments and interpreted the findings in ways that upheld the views of the time. His basic assumption, that measurements of the brain could rank humans on a linear scale of mental aptitude equivalent to their place in social hierarchy, was not only false, but also highly subjective, despite his support of scientific objectivity.
One canonical scientist in the field of neuroscience was anthropologist Paul Broca, known for the discovery of Broca’s area in the nineteenth century. Broca’s area is a brain region which when damaged, renders the patient unable to produce intelligible speech, although he or she retains the ability to understand language. Broca found an excellent example of a brain area that is responsible for a specific function, which drove the modern study of human neuroscience. Broca’s name also appears in Wikipedia’s Scientific racism entry. entry. In addition to his studies on stroke patients, Broca was a fan of craniometry, the measurement of skull size or brain volume. While craniometry is not inherently a discriminatory method, practitioners, Broca included, used their measurements to justify social views about women and minorities at the time, claiming that biological difference was proof of inferiority. Broca was not ill informed about scientific objectivity, and strove to meet the demands of this realm of thought, stating “there is no faith, however respectable, no interest, however legitimate, which must not accommodate itself to the progress of human knowledge and bend before truth.” While Broca
Broca’s time was over a century ago, and the optimist may suppose this incident was an isolated farce. Unfortunately, Broca is hardly the first and will not be the last person studying the brain to use the mask of objectivity. John Money, a psychologist and sexologist most known for work in the 1950s and ‘60s, had botched David Reimer ’s infantile circumcision. David no longer had a penis, and Money advised he be given a sex reassignment surgery and raised as a girl alongside his twin brother Brian. While Brian played with trucks, David, then known as Brenda, was given dolls. David and Brian attended multiple therapy session with Money geared toward convincing David that he was a girl and his brother was a boy who would fulfill their respective gender roles. Money was known well for his part in supporting the theory of hormonal organization of the brain to produce sexually dimorphic behaviors in animals. Much to the relief of parents at the time, he also supported the theory that for humans, gender identity and sexual orientation were a result of environment and upbringing alone. The doctor wrote extensively about the twins, highlighting David’s successful reassignment to the heterosexual female identity. In one of his many books, Money described his rigorous sys-
tem for interviewing subjects and cataloging their data that allowed “objectivity to reside in the scoring criteria”. As a mature adult, David Reimer found out what happened to him as an infant and why he had been so firmly pressed by his parents and Dr. Money into fulfilling the traditionally defined woman’s role. Brenda changed his name to David and began living as a man, but tragically committed suicide in 2004. Even today, studies like that of Skoe, Krizman, and Kraus (2013) uphold objectivity while trying to find “the biological signatures of poverty”. The authors attempt to link socio-economic status (SES) and differences in the brain’s response to sound. They use a “neurophysiologic test used to quickly and objectively assess the processing of sound by the nervous system,” which is interpreted by an audiologist. While the brain is quite malleable and the environment can and does affect neural circuitry, studies such as these can encourage the treatment of poverty as a disease. The language in the article suggests many possible methods of targeted “intervention” for low SES students. From this point, the leap is not large to consider these neural differences a factor in the perpetuation of intergenerational poverty. This type of approach can lead to interpretations not far from Broca’s if we suggest that these studies are purely objective.
edge does not pretend to disengagement” and is instead a collective of scientific voices that consider themselves rational but not invulnerable to their own background and bias. Objective research as it stands has offered much improvement to the scientific community and the method of inquiry since the nineteenth century, but the time has come to allow the definition of objectivity to morph. Let’s make an effort, in our reading and our own work, to acknowledge the subjective and take our biases into consideration. Objectivity is an ideal, but in reality, an eye that observes is not blind and should not pretend to be. The most beautiful photograph is crafted, not captured from the ether. The exposure, the contrast, the angle. The question, the hypothesis, the model. Perhaps most important for both photography and research, the interpretation. All of these aspects matter. Paying attention to each detail, ensuring no one feature overtakes the others, is the quality that separates the novice from the pro.
All of the scientists above were, and are, respected, intelligent, and creative individuals. All of them have used scientific objectivity. These scientists were most likely working in good faith and not intentionally biased. However, they were sorely misguided in applying objective measures to such a degree as to find themselves impervious to partiality. In trying to act as the disinterested observer, these researchers stumbled into the realm of ignorance, focusing on the experiment but not the outside pressures. They aren’t the only ones. The ideal of objective thinking can render scientists blind to the ways that the question begets the answer. Perhaps scientific objectivity then has no place in scientific practice. Donna Haraway, scientific philosopher and feminist, argues that objectivity in science should be discarded in favor of acknowledging the individual, both researcher and participant. She advocates for the idea of situated knowledges from multiple individuals, meaning that “rational knowl-
Recap: The Atlanta Science Festival
he sun’s barely out in downtown Atlanta on this cold Saturday morning, but David Nicholson, a graduate student studying Neuroscience at Emory University, is carrying a box labeled ‘Teaching Brains’ to one of – what seems like – a sea of white tents set up in Centennial Olympic Park. The banner outside his stall reads, ‘Hey, You Touched My Brain!’ “What’s in the box?” “Human Brains! We’re going to give people a chance to see what a brain actually looks like and try to teach them a little bit about how it works.” David is one of hundreds of scientists, engineers, and enthusiasts setting up their stalls to prepare for the Exploration Expo, which is the last hurrah hosted by the second annual week-long Atlanta Science Festival. In its inaugural year, the Atlanta Science Festival brought together 30,000 people into Atlanta’s
streets, classrooms, auditoriums, concert halls, squares, breweries, parks – you name it – to teach the public about science. “Why do you think what you’re doing is important?” I ask David as he puts on gloves to show me the brains. “Put quite simply, people want to do stuff. They don’t want to just be told about it. What we’re doing here today is hands-on work, and that makes a greater impact on people. You tell me, how many people have held an actual human brain in their hands?” And he was exactly right. Just in a few hours, the Exploration Expo was bustling with families, students, tourists, and enthusiasts, all being entertained by over a hundred interactive exhibits, hands-on experiments, mind blowing demos and a full line-up of science-themed performances. But the Expo was just the Festival’s way of ending with a bang.
Within a week, the Atlanta Science Festival hosted over 140 events celebrating science and technology attended by thousands of people. The events, approaching hands-on science in a plethora of different ways, ranged from talks held on the science of beer to robot demonstrations, with events geared towards people of all ages and interests. I got a chance to speak with Jordan Rose, one of the founders and directors of the Festival. Though he claimed he was exhausted, you couldn’t have guessed it. Springing with energy, he described how this year’s Atlanta Science Festival was different. “The events are just bigger, better, and more collaborative. And this is only the second year we’ve been hosting this.” I asked him what importance the Festival holds in the greater mission of communicating science to the public.
“Nobody gets to see science outside of the classroom or the lab. Science always happens behind closed doors. This is a way to get scientists and engineers outside those walls and into the community, giving them opportunities to interface with the public so that people can get excited about local opportunities for educational and scientific advancement. Science is usually lectures, talks, and panels, but that’s not what this festival is about. This is science in your face.” The effect that the festival had on the community was evident when I spoke with Lula Huber, an 8-year attending the Expo, about her experience. Having learned about the effects of pollution, she told me she wanted to organize a club in school to pick up litter on the streets so that she could contribute towards making earth a cleaner place. It didn’t seem that science class next week was going to be boring anymore.
Staying in Touch
ll too often scientists get caught up in the nuances of their individual research projects. They are so focused on the function of their protein or gene of interest that they forget about the ultimate goal of biomedical research: understanding and curing human disease. However, Emory has made several efforts to make sure that this is not the case for their graduate students. Emory graduate students have access to several avenues that help them stay in touch with the human aspect of research. These include the Molecules to Mankind Doctoral Pathway, the Certificate Program in Translational Research, and interactive courses such as Cancer Colloquium. The Molecules to Mankind Doctoral Pathway, or M2M, is an interdisciplinary effort that combines existing laboratory and population science Ph.D. tracks to create “a new breed of scientist.” Students that graduate from M2M are well suited for careers in public health as they are able to not only design and analyze laboratory experiments, but they can also integrate bench science to help solve population based health issues. Ashley Holmes, a third year Nutrition Health Science student in the M2M pathway, shared her perspective on the importance of keeping science in context: “I think it’s pretty easy to become hyper-focused on your dissertation topic and in doing so, you can unintentionally reduce people to data or biological samples. The M2M program addresses [this] issue in its awesome weekly seminars: the speakers usually have interdisciplinary backgrounds and interest-
ing collaborations that address basic, clinical, and population sciences. Even when the details of their experiments or statistical analyses get tedious, they “bring it home” by reminding us of the public health implications of their work and how they are helping people.” Rachel Burke, an Epidemiology student also on the M2M pathway, agrees. “I like how the M2M seminars try to bring things back to the practical application of the research — the ‘so what’ factor. I think that having this background has helped me in turn think about what are the implications of my research and how can I focus those towards helping mankind.” For more information on M2M visit their website: www.m2m.emory.edu Emory’s Certificate Program in Translational Research provides Emory graduate students, post-doc fellows, and faculty with an opportunity to bridge the gap between basic bench science and clinical research. This program has 14 credit requirements, including a clinical medicine rotation which allows program participants to shadow a clinician and interact with current patients. Katherine Henry, a third year student in the Molecular Systems Pharmacology program appreciates the unique perspective of translational research: “I have always been more interested in the translational aspects of science. I like science that I can
explain to my family and it’s a lot easier to do that when you can relate your work to some disease or physiological process. The hope is that this program will set me up for a career in clinical/translational science, for example at a clinical trials firm (CRO), or a public health agency like the CDC.” For more information about the Certificate Program in Translational Research follow this link: www. gs.emory.edu/sites/translational A third way Laney Graduate students can stay in touch with the human side of bench research is through courses with context such as the Cancer Colloquium course. This course is the capstone for the Cancer Biology Graduate Program. The course director is clinician Dr. Ned Waller, who treats patients as well as runs his own basic research laboratory. Dr. Waller brings oncologists and patients into the classroom setting to create an interactive and collaborative learning environment. The goal of this course is not only to explain to students how the cancers they research are treated but also to remind them of why they are performing this research. Katie Barnhart, a
third year Cancer Biology student currently enrolled in Cancer Colloquium says: “Courses like Cancer Colloquium allow students to make a connection between what they learn in a lecture setting and apply it to real world applications. We learn about molecular pathways and drug development, but to hear about how these therapies are affecting the lives of cancer patients helps put what we do in the laboratory into perspective. Courses like this help students to take a step back and remember the big picture.” Cancer Colloquium is offered every other Spring under the listing IBS 562. Emory students want their research to make an impact in the lives of patients and their families. M2M, the Certificate Program in Translational Research, and Cancer Colloquium provide pathways for students to reach out from their lab bench and stay in touch with the context of their research. In the age of interdisciplinary research, programs like these will become critical for advancing medicine.
Under-representation in research: Steps Toward Jadiel Wasson
ake a look around you. What do you see? Does your environment reflect what the real world looks like? If not, why do you think that is? How does this difference influence the nature of science? In the past few decades, this disparity of representation from different groups, specifically women and minorities, has become increasingly apparent. Many studies have demonstrated that this lack of diversity leads to a different kind of “brain drain” in that it caps interest in STEM careers in the up-and-coming generation which can ultimately take away minds that can contribute significantly to STEM. Although very few government initiatives have been put into place to address this issue, they have greatly influenced the demography of STEM degrees and careers. In addition to this, a handful of studies in conjunction with media attention have also altered diversity trends in STEM by bringing greater awareness to the underrepresentation that plagues these fields. But have has enough been done to truly alleviate this is-
sue? What steps have already been taken to address this issue of underrepresentation? Step 1: The Civil Rights Act of 1964 was the first step taken to address inequality in the workforce. This act significantly increased the availability of equal opportunities in education and employment for women and minorities. Before the implementation of this act, less than 5% of women earned PhDs in STEM careers. That number tripled to around 15% in the early 1980’s. In the late 1950’s, prior to any official census data, it was estimated that about 500 total African-Americans had a PhD of any kind. In 1975, only about 1.2% of PhDs were earned by AfricanAmericans. Step 2: The Science and Engineering Equal Opportunities Act of 1980 was mandated by the National Science Foundation to increase the participation of women in science. This act aimed to increase female
participation through various propaganda campaigns. These campaigns aimed not only to increase the public’s awareness of the value of women in science, but also to increase support for women who chose to pursue STEM careers by implementing committees, fellowships and programs. Since the inception of this act in 1980, the number of women holding STEM PhDs has increased from about 15% with STEM PhDs to fewer than 40% in 2011, lending to the effectiveness of such measures. Step 3: Beyond Bias and Barriers: Fulfilling the Potential of Women in Academic Science and Engineering is a national academy of sciences report that was published 2006. It is incredibly extensive in how it addresses the issues that still plague women in STEM disciplines that prevent them from advancing in their careers regardless of their academic stage. This report ultimately refuted many of the biases and “reasonings” behind the gap between men and women participation in STEM careers. Some of the key findings of this report include evidence of institutional biases against women and taking a look at the loss of women from each stage on the track to a career in STEM. One of the main contributions of this work came from some of the recommendations that were made to rectify the representation problem. In 2007, the National Institutes of Health, or NIH, created the working group on women in biomedical careers in response to the findings in the report. This
group has subsequently established many sub-committees with specific goals, such as public outreach and mentoring, all aimed at increasing the retention of women in STEM. Step 4: Current steps to enhance diversity in the STEM disciplines include the Enhancing the Diversity of the NIH-Funded Workforce program. This program was established in 2012 to increase underrepresented minorities in the STEM disciplines through a series of initiatives that will try to address how to keep minorities engaged in the STEM disciplines. Current state: Even with these steps there still remains a discrepancy in equal representation. For example, a recent report entitled “Double Jeopardy? Gender Bias Against Women of Color in Science” published online at www.worklifelaw.org in February of this year highlighted some of the prevalent biases that still plague women of color, such as differences in how they are perceived compared to their male counterparts. In addition to these findings, although we have seen the percentage of women employed in the STEM disciplines steadily increase each decade since the 1970’s, there has been a decline in this trend since 1990’s. All in all, initiatives to increase women in science have worked to a certain extent, but a large gap still remains. We need more measures that aid to reverse this trend.
Towards Precision Medicine: Promises and Hurdles Hyerim Kim
f you’ve ever seen an ad on the internet that seemed as if it was intentionally catered to your interests, you’ve probably been subject to customization in marketing. While mass customization has become commonplace in fields such as marketing and manufacturing, its scope is extending further than just business. Advances in genetics are allowing doctors to start customizing medical treatments for individuals through a new field being called ‘Precision medicine.’ Before precision medicine, diagnosis and treatment of disease was determined by categorization without consideration of individual diversity. These procedures, albeit leading to a huge improvement compared to non-scientific treatment, have brought concerns about diagnostic accuracy and side effects of prescribed medicine. Some of these concerns can be resolved by studies on the variation between the genes of different people. Scientists have launched international projects in order to illustrate the common patterns of human genetic variation. These ongoing efforts have helped in understanding why a certain population of people would be susceptible to a particular disease and what their responses would be to certain types of drugs. A medical movement applying individual genetic data into medical practice is considered as a milestone in the journey toward precision medicine. The movement is gaining momentum, with the President’s 2016 Budget allocating it a $215 million investment. In particular, the system is expected to reap enormous benefits in cancer treatment.
Hence, we can now ask ourselves: What’s the success story for precision medicine we’re looking for, and what are current challenges faced by this medical movement? Back in the 60s, chronic myeloid leukemia (CML) was a devastating disease and the average lifespan of patients was 3-7 years after diagnosis. However, a new genetic technique in 1970 enabled scientists to identify what caused the deadly disease, an abnormal molecule called Bcr-Abl. The elucidation of this abnormal molecule promoted the development of a new target therapy, “Gleevec” for CML patients. Since nearly all CML patients carry the fusion molecule, a therapeutic outcome was outstanding with higher efficacy and lower side effects compared to conventional chemotherapy. The success of Gleevec brought to the field a concept of targeted therapy in cancer treatment, resulting in the development of many similar therapies. A wider breakthrough in targeted therapy, however, could not be accomplished without further technological innovation. As technologies did develop, they were unfortunately too costly. However, newer sequencing platforms have led to the rapid reduction in DNA sequencing costs, and in the near future, $100 genome sequencing will be open to most people. As such, one can imagine genomic mutation profiling becoming routine in determining the best therapeutic regimens for individual cancer patients. Despite the mapping of a personal genome being expensive, the extraction of biological information
from complex human genomes is a major obstacle to the start a precision medicine era.
be able to access their own genomes so that they are able to play an active role in prevention of predisposed disease and treatment. Moreover, the pharTo illustrate, the detailed biological functions of maceutical industry will have to restructure itself protein-coding genes (1 % of human genome) still toward a more patient-oriented outlook. In terms needs to be explored, although the ENCODE Projof medical costs, we can save money from unnecesect launched to identify all functional elements of sary examination to identify the cause of disease. genome after the completion of the Human Genome As such, precision medicine is expected not only Project has brought about substantial understandto realize optimal medical services to patients but ing about the genome. In addition, most genomic also to transform medicinal industry in future. This regions outside of what codes for proteins (99 % realization, nevertheless, cannot be done by only an of human genome), such as promoters, enhancers, institute or a country. Collaborative research across and insulator regions that regulate gene expression, the world to clarify undermined and undiscovered remain to be elucidated. In particular, intergenic genomic data is essential. regions considered as â€œjunkâ€? DNA before are now thought to play regulatory roles in gene expression yet most of them remain uncategorized.. In other words, current genomic data is incomplete. In addition, there are no standard informatic programs to analyze raw sequencing data, and data storage and sharing are practical issues to be discussed. In order to overcome these limitations, international collaborations for breakthrough efforts are necessary. In the case of cancer research, The Cancer Genome Atlas in the US, the Cancer Genome Project in the UK, and the International Cancer Genome Consortium have been launched to aim for a deeper understanding of individual cancer patients by managing and sharing the data from these projects. Such combined efforts to elucidate the human genome, standardize data processing, and generate publicly available datasets will pave the way for precision medicine.
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Precision medicine is not a void dream. Along with technological innovation in genome research, individual diseases will be minutely categorized depending on an individualâ€™s genetic makeup, and treatments will be carefully chosen based off of that information. In addition, patients will
Explosive Elements: Ben Yin
*Just add Water*
In the pilot episode of the iconic 80s TV show, MacGyver, the titular character made his debut as a resourceful secret agent by making a sodium bomb to take down a wall, rescuing a couple of scientists. For MacGyver, with his extensive knowledge of the physical sciences, the process was simple: he immerses pure sodium metal inside a bottle of water and the explosive reaction between sodium and water is great entertainment for viewers of all ages. Today, this little display of pyrotechnic shenanigans is often seen in high school chemistry demos.
Alternatively, one can find many dozens of internet videos documenting this violent reaction between alkali metals like sodium or potassium and water, often accompanied by exclamations and whistles of joy. Itâ€™s no surprise that some of these videos have also gone viral. This amusing diversion of chucking alkali metals into water to watch it explode has been around since the 19th century and scientists have had a solid description of the nature of this reaction for about as long. Or so we thought. The classic explanation of elemental sodiumâ€™s volatile reaction with water involves the simple reduction-oxidation chemistry of sodium and water: electrons flow from sodium metal into the surrounding water, forming sodium hydroxide and hydrogen gas. This is a very fast reaction that produces a lot of heat. Hydrogen gas is extremely flammable in air, and in the presence of a heat source, this mixture can lead to a hydrogen explosion, not unlike the infamous incident that allegedly set the Hindenburg zeppelin aflame. The release of the large amount of energy in these reactions results in rapid expansion of the surrounding gas, which is what causes chemical explosions. Generations of chemists have accepted this seemingly obvious explanation without much deliberation. It is perhaps surprising then, that one curious soul decided to look at this century-old reaction more in-depth. Philip Mason earned his PhD in chemistry and has co-authored more than 30 scientific papers, but is probably better known for his YouTube channel,
where he regularly posts videos, often in vlog format, under the pseudonym “Thunderf00t” (yes, that’s two zeros substituting for the letters “O”). His favorite post topics are often pieces of popular science he encounters, and Mason has earned the support of a huge public following with his YouTube channel. In 2011, using donations from some of his more than 300,000 YouTube subscribers, Mason purchased the materials and consumer grade high-speed cameras necessary to look at what he thought would be “home chemistry.” The YouTube project, it turns out, raised many questions, for which Mason found traditional answers unsatisfactory, namely the explosive nature of alkali metals in water. Compelling footage also showed a secondary gas explosion above the water surface that resembles a hydrogen explosion, demonstrating that the initial stronger and faster explosion can’t be explained with our traditional understandings of this reaction. Some scientists have suggested, instead, that the explosion is caused by the sheer amount of heat released during the reaction. If this were the case, the heat would boil the water and a rapid generation of steam leads to explosion. Mason remained unconvinced. A key insight by Mason and his colleagues was that as hydrogen and steam are generated when the alkali metal comes into contact with water, the interface between the metal and water should be blocked off by the products and therefore inhibit further reaction. This would result in the exact opposite of the explosive reactions being observed. Crucially, immersing solid chunks of sodium and potassium under water still results in rapid explosions, so this too could not be the explanation for the initiation of the explosion. These enigmas led Mason to bring his YouTube project into the lab. To get a better look at the reaction, Mason and his colleagues turned to research grade high-speed cameras. Filming at around 10,000 frames per second, they were able to capture the beginning of the reaction between alkali metals and water in astounding detail. What they captured is striking: the reaction is immediate, and the metal shatters on contact with the water surface. Within two-ten thousandths of a second, spikes of metal are flying apart from anywhere the surface touches water. As the sheer force of the rupturing metal bursts forth, a
brilliant blue wash appears to stain the blast of water in the very next frame. This stunning blue color is due to solvated electrons in water, which is usually far too short-lived for people to see. What isn’t so easy to interpret are the metal spikes flying apart, piercing the water in the process. However, with some chemical intuition and computing time on supercomputers, Mason and his colleagues came up with an explanation for this observation that ultimately describes the explosive nature of alkali metals in water. When large numbers of electrons escape from the alkali metals into the surrounding water, the metal itself becomes extremely positively charged. Like the static charges that can make our hair spike up for that mad scientist look, the positive metal atoms now repel each other, except with much more violent force. Atoms that were previously bonded together as a solid now suddenly fly apart at extraordinary speed. This, in turn, exposes fresh metallic surfaces to water for the explosive reaction to take place. This little-known phenomenon is called Coulomb explosion. The immediate application of this knowledge for preventing explosions in industrial use of alkali metals will be useful. Just as important, the discovery of this mechanism of explosion in a chemical reaction over a century old reminds us not only of how little we know, but also how much we simply fail to even consider. In the face of public apathy for science, it is encouraging that such a significant scientific discovery should come from a YouTuber, funded partially by the YouTube community, and documented in vlog format throughout the research process. It leaves us wondering what other remarkable discoveries such public engagement could lead to. Mason and his colleagues published their research in the February issue of Nature Chemistry, they acknowledged the support of his YouTube followers. Link for video: https://youtu.be/LmlAYnFF_s8 Link for article: http://www.nature.com/nchem/journal/v7/n3/full/nchem.2161.html
Solar Water Splitting: Future Paths to Clean Unlimited Energy Marika Wielickzo
With recent advancements in science, the ability to artificially split water – much like what plants do all the time – might be humanity’s way of finally having access to unlimited clean energy. Looking back, one of the most important scientific developments of the 20th century was the industrial synthesis of the compound ammonia from nitrogen and hydrogen. Analogous to the oxygen atom in water, H2O, ammonia, or NH3 is the most basic combination of nitrogen with the simplest element, hydrogen. Developed initially for military applications, the revolutionary Haber-Bosch process, compresses nitrogen gas and hydrogen gas under extreme conditions to yield ammonia. The ability to produce ammonia from its elements facilitated an unprecedented boom in human population. Living things require useable forms of nitrogen for making proteins and DNA, but most of the nitrogen on the planet is in the form of unreactive nitrogen gas, which is the bulk of the air we breathe. Unlike the oxygen, which most organisms use for metabolism, nitrogen gas is almost completely unreactive. Only a handful of microorganisms are capable of “fixing” the N2, by breaking its very strong nitrogen-nitrogen bond so that the individual nitrogen atoms can be used in more complex molecules
required by the organism. Before the Haber-Bosch process was developed, the amount of usable nitrogen on the planet was limited by the rate at which these microorganisms could enrich the soil with usable nitrogen to incorporate into the food chain, which by then had essentially plateaued. Once human beings mastered the ability to fix nitrogen on their own, the bottleneck that had been keeping population growth in check was gone, and in only one hundred years, 1.6 billion people grew to over 6 billion. Such a dramatic and sudden increase in the population has led to fears of overpopulation, and the consequences for the environment of the additional demand for resources and surplus waste. Scientists have long recognized the need for sustainable energy; most current sources, such as burning fossil fuels, are not renewable and release excess waste that is unlikely to be inconsequential on this massive global scale. One of the most promising sources of sustainable energy is sunlight, and provided we can find ways to convert that light energy into solar power we can use efficiently, could sustain all of the planet’s energy needs for generations to come. Plants, and a handful of microorganisms have been capturing and harvesting solar energy for millions of
years through photosynthesis. In this process, energy from sunlight is used to convert carbon dioxide and water into carbohydrates, or sugars. The waste product is molecular oxygen, the essential component of the air we breathe. The energy is stored in the chemical bonds until they are broken during metabolism. In effect, all of the oxygen on Earth originated through this process, and allowed for the evolution of complex life. Whether it occurs in plants or bacteria, photosynthesis begins with the absorption of light. The light energy is transferred to an electron in the light-absorbing molecule. In this energetically excited state, the electron can be captured by a neighboring acceptor molecule, leaving a positive “hole” behind. The electrons to neutralize these positive holes are harvested from water by the oxygen-evolving complex, or OEC. The OEC contains four manganese ions and one calcium, arranged in a cube-like shape, along with several oxygen atoms and water molecules. The cluster takes two water molecules and combines them into molecular oxygen, O2. The process has been studied thoroughly, but many of the details are not completely understood. We do know that the process occurs in steps, and the positively charged hydrogen ions, H+, are released in sequence, and kept separated from the negatively charged electrons in order to generate a potential across the cell, that it can use for energy. Both metabolism and combustion of fossil fuels are effectively the reverse of photosynthesis. In the presence of oxygen, molecules that contain carbon and hydrogen are converted into carbon dioxide and water. Despite debates over the existence or causes of climate change, scientists have long anticipated the need for sustainable sources of renewable energy, and have recognized that one of the most promising paths is to learn from nature and develop technology for artificial water splitting and solar energy capture. Significant progress has been made in recent years, with, for instance, the appearance of so-called “artificial leaves”. Usually, in artificial systems and plants alike, each of the overall reaction steps is accomplished by separate components. One component absorbs light, another generates oxygen and still another for managing protons or hydrogen produc-
tion, in addition to other components that may be needed to keep the oxygen and hydrogen reactions separated, as both do not usually occur under the same conditions. One particularly exciting system was recently reported by researchers in China and Israel. These scientists, led by Zenhui Wang, have discovered that by combining two materials, carbon nitride and carbon nanodots, an indirect route involving hydrogen peroxide allows for a synergistic effect. While each component alone is a capable catalyst, carbon nitride is quickly deactivated by the products it generates. When combined however, each component alleviates shortcomings of the other. This solid material, when placed in water and irradiated with light, generates a 2:1 ratio mixture of H2 and O2 gas. This particular system is difficult to understand, and almost seems too good to be true. The major drawback is that this mixture of gases is explosive, ideally they would be generated in separate, isolated components. Another weak point is the overall efficiency, when comparing the energy stored in the chemical bonds of O2 and H2 that are formed to the energy in the light needed to drive the process. While the efficiency is far from optimal, the material is made of abundant elements and is extremely stable, and after 200+ days of continuous use, the material continues to steadily split water using sunlight. Nature often serves as a source of inspiration or guidance, but artificial systems address different needs. While it is amusing to imagine putting water into the gas tank of a solar-powered car, with only water vapor on the tailpipe end, the need for technology for splitting water into O2 and H2 is more extensive than that. The Haber-Bosch process, after all, relies on the reaction of N2 and H2, and the ultimate sources of H2 are typically fossil fuels. Water splitting technology, especially if powered by sunlight, holds enormous promise for changing the way we use resources by closing loops in inefficiency and reducing or even eliminating unnecessary waste. Solar water splitting continues to be an active and exciting field of research, and in the face of impending urgency for green technology, may one day be called the most important scientific development of this century.