Staples STEM Journal: Issue No. 8

Staples STEM Journal

2019 International Collaboration

Editor-in-Chief: Emma McKinney ‘19 Assistant Editor: Nora Dockter ‘20 Senior Layout Editor: Carter Teplica ‘19 Associate Layout Editor: Whitman Teplica ‘23 We are thankful for the support of our fabulous advisor, Ms. Karen Thompson.

Guest Writers: Jasmine Cheng, Canada Matthew Liang, Singapore Aleksander Łysomirski, Poland Aleksander Stawiarski, Poland Paul Mark Tammiste, Estonia Barbara Walkowiak, Poland Staples High School Writers: Sarah Corneck ‘21 Kate Enquist ‘20 Lys Goldman ‘21 Chloe Palumbo ‘19 Maya Reiner ‘21 Derek Ye ‘21 Special thanks to Samuel Powell ‘21, who kindly agreed to withhold his excellent article on CRISPR until the next issue due to space constraints.

Copyright © 2019 by Staples High School STEM Journal. All rights reserved.

Printed for June 2019.

The Staples STEM Journal aims to further curiosity in and broaden understanding of science, technology, engineering, and math, and to provide individuals with an outlet to share their interests with the Staples community.

Table of Contents Letter from the Editor ..............................................................................................4 1. Bacteria: A Tiny Solution to our Giant Food Crisis? .............................................. 5 Jasmine Cheng, Canada 2. CRISPR: The Solution to Coral Bleaching? ........................................................... 8 Sarah Corneck, Staples High School ‘21 3. The Consequences of Chronic Stress ................................................................. 11 Kate Enquist, Staples High School ‘20 4. Don’t Sit Still: The Benefits to Fidgeting ............................................................ 14 Lys Goldman, Staples High School ‘21 5. Current Wars: AC vs. DC ..................................................................................... 16 Matthew Liang, Singapore 6. Plant Medicine: Flavonoids and their Role in Inducing Death in Senescent Cells ..............................................................................................................................22 Aleksander Łysomirski, Poland 7. The Search for a Cure: The HIV Pandemic .......................................................... 28 Chloe Palumbo, Staples High School ‘19 8. A Common Anesthetic: Can It Possibly Help Individuals with Post-Traumatic Stress Disorder? .......................................................................................................... 30 Maya Reiner, Staples High School ‘21 9. Does Talking On Your Phone Affect Your Brain’s Metabolism? ......................... 32 Aleksander Stawiarski, Poland 10. Huntington’s Disease ......................................................................................... 38 Paul Mark Tammiste, Estonia 11. Eat Your Fruits and Veggies: AMP-Activated Protein Kinase—The Energy Sensor in the Cell and its Activators ............................................................................ 41 Barbara Walkowiak, Poland 12. The Protein Paradox ..........................................................................................46 Derek Ye, Staples High School ‘21

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Letter from the Editor Dear Reader, As another school year comes to a close for the Staples STEM Journal, it is the perfect time to pause and reflect on the many advances made possible by an outstanding team of writers, editors, and advisors. At the start of this year, I was amazed at the sheer curiosity and writing skill held by each and every member of the journal. Led by this drive, we were able to publish not only issues spanning wide varieties of STEM topics, but also a themed supplement honoring the history of women in STEM — a first for the Staples STEM Journal. With the help of our wonderful staff advisor, Ms. Karen Thompson, we were also privileged to collaborate with high school student-writers from across the world, the result of which is in your hands at this very moment. In our first-ever International Issue, you will find the work of both fellow Staples students and our peers abroad, many of whom have conducted independent research outside the classroom. I applaud the hard work of the writers, and hope you find as much interest in their work as I did.

This last issue for 2018-2019 marks a bittersweet goodbye for me and all of the journal’s senior members, but also a turning page for a new year and new writers. As we look forward to the future of the journal, I have no doubt that it will continue to expand and evolve for the better given the drive and passion I’ve seen in each and every member, the insight of next year’s leadership team, and the invaluable guidance of our staff advisor, Ms. Thompson. Until then, keep thinking, learning, and exploring the wonderful world of STEM! Happy Reading!

Emma McKinney ’19, Editor-in-Chief

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1. Bacteria: A Tiny Solution to our Giant Food Crisis?

Jasmine Cheng, Canada My name is Jasmine Cheng and I am in grade 11 at Fort Richmond Collegiate in Winnipeg, Manitoba, Canada.

My research is super important to me as it is inspired by my mother.

It is universally acknowledged that food scarcity is already a global issue, so what is going to happen in 2050 when the world population reaches a projected all-time high of a staggering 9.7 billion people? [1] Scientists estimate that worldwide food production must increase by 60-70% to meet the rising demands for food [2]. Our current agriculture methods are not adequate and a new solution to our food crisis must be developed - and soon! However, not every method for increasing production is necessarily advantageous. Farmers use chemical pesticides to increase output, and while the increase in food production is welcomed, these bolstered yields come at a cost. According to the World Health Organization, pesticides can be harmful to humans, causing problems such as cancer, reproductive issues, and adverse effects on immune and nervous systems [3]. Why not solve both these problems at once and come up with a more sustainable and healthier method to grow our food?

Plant Growth Promotion Currently, limited amounts of resources, such as water, but more importantly field space, are the main limiting factors to our agriculture industry; plant growth promotion may be the answer to this problem.

This method works by increasing the size, and consequently the yield, of the plant, thereby decreasing the overall amount of resources needed to grow sufficient amounts of food. With the help of Dr. Teri de Kievit and Dr. April Gislison from the University of Manitoba, I wanted to determine if it were possible to utilize bacteria to promote plant growth. Using bacteria is by no means a novel approach to the global food crisis; however, the novelty of my research lies in the question of whether the secondary metabolites produced by the bacteria could help with plant growth promotion when introduced to the rhizosphere, i.e., the root system of the plant.

Secondary Metabolites Produced by Bacteria Bacteria produce two types of metabolites: primary and secondary. Primary metabolites are fundamental for growth and development. In contrast, secondary metabolites are compounds produced by the bacteria that aid the bacteria in other ways and tend to be more critical for increasing the duration of a bacteria’s lifespan. While the primary metabolites produced by different bacteria are

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consistent, the secondary metabolites produced vary based on the strain of bacteria. Secondary metabolites include compounds such as antibiotics, essential oils, and steroids [5].

Figure 1: Plant growth promoting rhizobacteria (PGPR) [4].

Investigating the Effects of Secondary Metabolites on Plant Growth The actual mechanisms behind plant growth-promoting bacteria are not fully understood, so I hoped that observing the effect of secondary metabolites on plant growth would elucidate this phenomenon.

This was achieved by taking two strains of the bacteria Pseudomonas chlororaphis, strain PA23. One was the wild type, or natural, strain, and the other was a mutant strain that was unable to produce secondary metabolites. The mutant was named gacS, due to the fact that it was the gacS global regulator that was inhibited [6]. The bacteria was tested on a plant called Arabidopsis thaliana, a common model plant used in biology.

Figure 2: A. thaliana plant used in the study [7].

The plants were grown hydroponically, which is a method of growing plants in water or media instead of in soil, to ensure that no other bacteria found naturally in soil would impact the results. As the plants grow rapidly, 17 days post-inoculation of the bacteria, the plants were observed and the final data was collected.

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Figure 3: Plants 17 days post inoculation. Figure 4: Plants once they were removed from the hydroponic system.

The plants were removed from the hydroponic system, and both the wet and dry masses of the plants were taken.

It was found that the plants exposed to secondary metabolites experienced a stunted growth relative to the mutant strain and the control (the control was not inoculated with any strain of bacteria).

This finding suggests that the secondary metabolites are harmful and toxic to the plant growth. The mutant strain, on the other hand, was significantly larger than the control, which leads to the conclusion that some aspect of the strain was contributing to plant growth promotion.

Moving Forward It’s more vital than ever before that a productive way to increase our agriculture production must be developed. By using bacteria to help plants grow, I was hoping to find a greener and more sustainable method of expanding the capacity of our agricultural sector. While the mutant strain of bacteria did augment the plant growth, the mutant was missing the secondary metabolites crucial for fighting off the naturally-occurring pathogens and pests in the field. This is not the straightforward solution I was hoping for, the study could serve as a foundation for many more studies to come in the future, to develop a more environmentally-friendly and sustainable method of agriculture.

Works Cited [1] P. Gerland et al., “World population stabilization unlikely this century,” Science, vol. 346, no. 6206, pp. 234–237, Oct. 2014.

[2]Thematic Group on Sustainable Agriculture and Food Systems, “Transformative changes of agriculture and food systems.”

[3] “WHO | Pesticide residues in food?,” WHO. [Online].

[4] J. Vacheron et al., “Plant growth-promoting rhizobacteria and root system functioning,” Front. Plant Sci., vol. 4, 2013.

[5]“Difference Between Primary Metabolites and Secondary Metabolites (with Comparison Chart),” Bio Differences, 20-Jul-2017. .

[6] Poritsanos, N., Selin, C., Fernando, W.G.D., Nakkeeran, S. and de Kievit, T.R., “A GacS deficiency does not affect Pseudomonas chlororaphis PA23 fitness when growing on canola, in aged batch culture or as a biofilm,” Canadian Journal of Microbiology, no. 52, pp. 1177–1182, 2006.

[7] “Arabidopsis thaliana - mouse-ear cress | LIS - Legume Information System.” [Online].

[8] “Agriculture :: PlasticsEurope.” [Online].

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2. CRISPR: The Solution to Coral Bleaching?

Sarah Corneck, Staples High School ‘21 Coral reefs are crucial to our world. We love reefs because of their incredible beauty, but more important, coral reefs provide critical habitat to millions of species. They are also primary producers and help maintain the biodiversity of the most diverse habitat in the world [2]. Billions of species - humans, as well as animals - rely on coral reefs for both work and nutrients [7]. Years ago, no one had to imagine what a world without coral reefs would look like, but recently, coral bleaching has become such a problem that coral is in danger of becoming destroyed and even eradicated.

Left, a healthy coral reef [5]. Right, a bleached reef [14].

Corals get their color from the symbiotic algae, zooxanthellae, that live within them [12]. The photosynthetic algae dwell in the coral and convert light into energy which the coral absorbs as food [3].

Coral bleaching occurs when stressors cause the coral to expel the algae, thus losing their color and turning bone white [6]. Corals are stressed in one of two ways: a change in heat or a chemical imbalance.

This abnormality does not have to be large; even a 1-2oC fluctuation could have disastrous effects, leading the algae to stop photosynthesis [9] The coral, noticing the change, expels the algae, thinking it is defective. In a normal environment, the coral would be able to find new algae to replace the expelled, but with the ongoing warming of the ocean, the corals are dying before that is possible [6].

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Coral bleaching has happened in the past, but never for as long duration or as severe a loss. This current string of coral bleaching started in 2014 and has only degenerated further. Over two-thirds of coral reefs have been affected by bleaching and some researchers predict that all corals will be under the threat of bleaching by 2040 [8]. It’s becoming increasingly apparent that this situation will not improve on its own; the algae are adapting too slowly to keep up with the rising temperatures. Sadly, if the corals were making some rapid evolutionary change, there would be evidence of it by now [5]. Many coral experts are now calling for a ‘radical intervention’ if the corals are to be saved. Luckily, there are a group of biologists that are working on just that.

The threat on coral reefs is just intensifying year to year [13].

The results of a study were just published in the Proceedings of National Academy of Sciences, in which the gene-editing software, CRISPR, was used to modify the DNA of corals in the Great Barrier Reef. The group of scientists, a collaboration between Stanford Medical School, UT Austin, and the Australia Institute of Marine Science, were the first to be successful in this endeavor [1]. The idea, using CRISPR to enhance the resilience of coral, was introduced back in 2015, but researchers encountered a number of challenges. The first of which is the short reproduction cycle of the coral. CRISPR works best if implemented at the beginning of an organism’s life, and with corals, there is a very narrow opportunity during which this occurs. In the middle of the night, one day a year, the corals release bundles of sperm andeggs which will float to the surface. At the surface of the water, they will combine, sink, and start to grow on a rock at the bottom of the ocean [12]. To address this challenge, the Australian component of the research team has been observing the reefs and managed to predict the spawning cycle within just a few days of variance [1].

Because this was the first time using CRISPR to modify corals, the goal was not to solve coral bleaching. In fact, so little is known about the coral’s genome that the researchers wouldn’t even know which genes to manipulate. Instead, the researchers chose to edit GFP, RFP, and FGF1a genes, which are all involved in the coral’s fluorescence. They microinjected CRISPR/Cas9 into the fertilized egg of coral species Acropora Millepora. This species was chosen for its ecological significance to the Indo-Pacific region, its abundance near the testing sight in Australia, and its semi-predictable spawning. This experiment showed the first definitive evidence that CRISPR could be used to modify corals, in the hope that scientists will eventually be able to create coral that are resilient against ocean warming [2].

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Left, corals releasing bundles of egg and sperm under moonlight [6]. Right, how corals reproduce [6].

The research team stresses the fact that they are not trying to make “super corals.” That level of biological manipulation is currently implausible and would raise multiple ethical questions. Right now, what is really necessary is to determine the basic mechanisms of how coral functions, and to inform conservation efforts in the future. In the words of Dr. Philip Cleves of Stanford University, “...perhaps there are natural gene variants in coral that bolster their ability to survive in warmer waters; we’d want to know that.” [1]. The team wants to slowly begin modifying genes that are more closely related to the symbiotic relationship with algae, saying that they “...hope that future experiments using CRISPR-Cas9 will help us develop a better understanding of basic coral biology that we then can apply to predict — and perhaps ameliorate — what’s going to happen in the future due to a changing climate…” [1]. This genetic engineering has the potential to speed up adaptation, and allow coral to survive despite their changing environment.

Works Cited [1] By Hanae Armitage Hanae Armitage is a science writer for the medical school’s Office of Communication & Public Affairs Email her at harmitag@stanford.edu, “CRISPR used to genetically edit coral,” News Center. [Online].

[2] P. A. Cleves, M. E. Strader, L. K. Bay, J. R. Pringle, and M. V. Matz, “CRISPR/Cas9-mediated genome editing in a reef-building coral,” PNAS, vol. 115, no. 20, pp. 5235–5240, May 2018.

[3] “How Gene Editing Could Save Coral Reefs,” Time. [Online].

[4] “Scientists have genetically engineered coral to save reefs from climate change,” The Independent, 23-Apr-2018. [Online].

[5] K. Frischkorn, “A Blueprint for Genetically Engineering a Super Coral,” Smithsonian. [Online].

[6] W. Cornwall, “Researchers embrace a radical idea: engineering coral to cope with climate change,” Science, 21-Mar-2019.

[Online].

[7]Martin, “Oceans,” United Nations Sustainable Development. .

[8] “Newsela | Australia’s Great Barrier Reef losing brilliant colors to climate change.” [Online].

[9] “Gmail.” [Online].

[10] “Newsela | Scientists study Persian Gulf reefs for coral survival clues.” [Online].

[11] “Opinion | How to save the ‘tropical rainforests’ of the ocean,” Washington Post. [Online].

[12] K. Marhaver, How we’re growing baby corals to rebuild reefs.

[13] “Unprecedented 3 years of global coral bleaching, 2014–2017 | NOAA Climate.gov.” [Online].

[14] “Mass coral bleaching hits the Great Barrier Reef – again.” [Online].

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3. The Consequences of Chronic Stress Kate Enquist, Staples High School ‘20 In a recent study by the American Institute of Stress, 77% of American adults reported feeling stressed on a regular basis. This percentage has been steadily increasing since the late 2000s [1]. These trends are particularly alarming, since chronic stress can often lead to many health issues [4]. In order to ultimately combat this chronic stress and its resulting health issues, it’s incredibly important to understand the science surrounding its physiological effects.

How the Stress Response Works When an individual hears or sees something, the brain processes that information in the amygdala [5]. If the brain perceives that stimulus as potentially dangerous, it uses the hypothalamus to release corticotropin-releasing hormone (CRH), which travels through the sympathetic nervous system to the pituitary gland. The pituitary gland then releases adrenocorticotropic hormone (ACTH) to the adrenal gland, which is located above the kidney [4]. Finally, the kidneys release the hormones adrenaline (also called epinephrine) and cortisol into the bloodstream. Adrenaline increases the amount of blood in the muscles, heart and other vital organs. Hearing, sight, and other senses become sharper. The airways open and the lungs take in extra oxygen, which is sent to the brain to increase alertness. Blood pressure, pulse rate and breathing rate also rise due to the increased levels of cortisol. Glucose and fats are released from temporary storage sites in the body, supplying the extra energy. These changes occur so rapidly that people often don’t notice them. The body temporarily shuts down the production of reproductive hormones and decreases immune system function. After the person no longer perceives a threat, the stress response ends [2]. Adrenaline and cortisol levels return to normal, reversing the effects of the stress response.

How Chronic Stress is Different When an individual continues to perceive a danger or threat, the stress response doesn’t end. Elevated levels of cortisol and epinephrine remain in the body and cause physical health issues in the cardiovascular, digestive, immune and reproductive systems [3].

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Left, a visual of the stress response [6]. Right, impacts of long-term stress [7].

Physical Health Impacts In the cardiovascular system, the blood vessels dilate to increase the blood flow through them during the stress response. With chronic stress, this vasodilation and the increased blood pressure damages the blood vessels. As a result, the blood vessels become more rigid, making it harder to move blood through them [2]. This causes the body to increase the blood pressure long-term to ensure enough blood is circulated; this condition is known as hypertension. The damaged blood vessels are also susceptible to plaque build-ups that can potentially block the entire vessel and cause cardiac disease [3].

Chronically-elevated cortisol levels increases metabolism and causes blood sugar levels to be constantly elevated. With an increased metabolism, individuals feel the need to eat more than necessary and consume excess calories. This can lead to weight gain and its many accompanying health ramifications. Additionally, elevated blood sugar levels can exacerbate type 2 diabetes [2].

Cortisol also suppresses the release of reproductive and pregnancy hormones, such as estrogen.

When stress is constant, the hormones are always suppressed, causing reproductive issues in both sexes. Women often miss their periods or are unable to become pregnant. Men often experience erectile issues [4].

The stress response also suppresses the production of fighter cells in the immune system. With fewer of these cells, the body can become sick faster and form an attenuated strain of a pathogen.

Chronic stress also causes the body to stop activating the immune system appropriately [2]. This can result in the body attacking healthy cells, leading to autoimmune diseases such as arthritis. The body also heals wounds at a slower rate, increasing the time where that area is vulnerable to infection [4].

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Mental Health Ramifications Chronic stress has major psychological impacts, as it’s known to diminish brain function. According to multiple studies, chronic stress can disrupt synapse regulation, decreasing a person's desire and ability to socialize. Brain cells can also be killed, impairing other brain functions [3]. This is especially apparent in the prefrontal cortex, diminishing a person’s impulse control, judgement, and ability to plan. The size of the amygdala is sometimes increased, making the brain more susceptible to stress. According Christopher Bergland in Psychology Today, “Cortisol is believed to create a domino effect that hard-wires pathways between the hippocampus and amygdala in a way that might create a vicious cycle by creating a brain that becomes predisposed to be in a constant state of fight-or-flight...” [5].

Scan of a healthy brain (left) versus one exposed to chronic stress (center) [10]. Levels and Impacts of Stressful Experiences (right) [9].

How to Combat Chronic Stress Considering that chronic stress is clearly harmful to one’s physical and mental health, it’s incredibly important to learn how to effectively cope with stress [4]. There are two main strategies to accomplish this.

Dr. Herbert Benson, director of Mind Body Medicine at Massachusetts General Hospital, claims that relaxation techniques can be used to calm the body and end the stress response. These include deep breathing, focusing on relaxing words, visualizing peaceful memories, yoga, and tai chi. Secondly, engaging in physical activity focuses the mind on that activity rather than the stressor. This by itself can decrease stress, but exercise can also deepen breathing and relax muscles, helping combat some harmful side effects [3].

Works Cited [1] “2015 Stress in America Snapshot,” https://www.apa.org. [Online].

[2] Khan Academy. (2019). Physical effects of stress. [Online].

[3] “Chronic stress puts your health at risk,” Mayo Clinic. [Online].

[4] H. H. Publishing, “Understanding the stress response,” Harvard Health. [Online].

[5] “The Mind and Mental Health: How Stress Affects the Brain,” Touro University WorldWide, 26-Jul-2016. [Online].

[6] “Brain-Based Approach to Peace: Stress Impairs Brain Functioning – GUSP.” .

[7] “Slideshow: Stress and Your Body,” WebMD. [Online].

[8] Her, “Understanding Chronic Stress,” LegaSE Spiritual Enlightenment, 23-Feb-2018. .

[9] “Toxic Stress,” Center on the Developing Child at Harvard University. [Online].

[10] “Stress Affects Health of Brain and Heart, Study Reveals,” KVC Health Systems, 23-Jan-2017. [Online].

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4. Don’t Sit Still: The Benefits to Fidgeting Lys Goldman, Staples High School ‘21 You sit at your desk and bounce your leg up and down. You look around and notice a classmate drumming her foot against the floor. Another classmate twirls his hair in and out of his fingers. Another raps his pencil against the hardwood surface of their desk. Another idly doodles on a sheet of notebook paper. All of these actions and countless more constitute fidgeting, a ubiquitous act that you probably do many, many times a day. Although some believe it to be simply an annoying habit, research has found that fidgeting actually produces a multitude of benefits.

One benefit of fidgeting is a longer attention span. A study led by psychology professor Jackie Andrade found that doodling, considered one form of fidgeting, helped people maintain attention and remember more. The study involved 40 participants monitoring a phone call for the names of people coming to a party, with half of the group allowed to doodle while listening. On a surprise memory test, the doodling group recalled 29% more information than the non-doodlers [2]. In addition, a preliminary study piloted by Sheryl Stalvey investigated the effects of having sixth-graders fidget with stress balls during school. After observing the students for three weeks without the stress balls and seven weeks with them, Stalvey found that the frequency of distraction incidents decreased, attention spans increased, and based on the students’ journal entries, “...all types of learners thought that their attitude, attention, writing abilities, and peer interaction improved due to stress ball use...” [4].

A possible explanation for why fidgeting helps sustain attention is that it provides physiological stimulation. A study conducted by researcher James Levine and colleagues measuring energy expenditure of non-exercise activities, found that compared to the metabolic rate of a person in the supine position, energy expenditure increased by an average of 54% while seated and fidgeting but only 4% while seated motionlessly. Moreover, energy expenditure increased by an average of 94% while fidgeting standing and only 13% while standing still [3]. These results suggest that fidgeting can help sustain attention by increasing physiological change.

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Improved attention span is not the only positive effect that stems from fidgeting. Though it may come as a surprise, fidgeting can also have a substantial and beneficial impact on weight management.

This was shown through a study also led by researcher James Levine. Levine and his colleagues overfed a group of healthy, non-obese participants by approximately 1000 calories above their weight maintenance requirements each day for eight weeks. Rather than simply put on weight, the participants’ bodies appeared to have a large increase in fidgeting, posture changes, and random muscle tensing to fight back against the overfeeding [5]. This increase in spontaneous movements helped to combat the weight gain that would have resulted from overeating. Although fidgeting is comprised of mostly small movements, these small movements can make a much bigger impact than expected. In fact, fidgeting can account for between 100 and 800 extra calories burned off per day [6].

While many people may discourage fidgeting and brush it off as a meaningless and bothersome tendency, scientific research has shown that fidgeting does in fact have multiple benefits, including an improved attention span and weight regulation.

Works Cited [1] H. Dempsey-Jones, “The surprising science of fidgeting,” The Conversation. [Online].

[2] J. Farley, E. Risko, and A. Kingstone, “Everyday attention and lecture retention: the effects of time, fidgeting, and mind wandering,” Front. Psychol., vol. 4, 2013.

[3] J. A. Levine, S. J. Schleusner, and M. D. Jensen, “Energy expenditure of nonexercise activity,” Am J Clin Nutr, vol. 72, no. 6, pp.

1451–1454, Dec. 2000.

[4]S. Stalvey and H. Brasell, “Using Stress Balls to Focus the Attention of Sixth-Grade Learners,” Journal of At-Risk Issues, vol. 12, no. 2, pp. 7–16, 2006.

[5] J. A. Levine, N. L. Eberhardt, and M. D. Jensen, “Role of Nonexercise Activity Thermogenesis in Resistance to Fat Gain in Humans,” Science, vol. 283, no. 5399, pp. 212–214, Jan. 1999.

[6] E. Ravussin, S. Lillioja, T. E. Anderson, L. Christin, and C. Bogardus, “Determinants of 24-hour energy expenditure in man.

Methods and results using a respiratory chamber,” J. Clin. Invest., vol. 78, no. 6, pp. 1568–1578, Dec. 1986.

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5. Current Wars: AC vs. DC Matthew Liang, Singapore My name is Matthew Liang. I reside in Singapore and am currently a Secondary 4 student studying in the School of Science and Technology (SST). My research on the Skin Effect has been a very fulfilling experience for me during my education journey in SST. I think regardless of any research anyone has done, the challenges are always paramount. Determination and perseverance have definitely been a key to my success on this project. During my free time, I enjoy watching movies and rock climbing.

The War of the Currents Edison developed the first light bulb in the 1870s and started building a power system so that homes and offices could use his invention. He opened his first power plant in 1882, and soon his power system -- the Direct Current (DC) system -- was used throughout the United States. A few years later, Nikola Tesla invented and developed the Alternating Current (AC) power transmission system [1].

These inventions started an era known as the “War of the Currents” -- a series of events illustrating the competition between the AC and DC systems [1]. The competition had become so intense that Edison started to falsely mislead Americans so as to discredit Tesla’s AC system [2]. Fast forward to today, and we see that the AC system is the dominating power system, commonly used to power households, offices, and buildings [2]. AC won because it is easy to convert into higher or lower voltages using a transformer, and it is easier to transmit over long distances [2].

Now, however, the DC system is starting to make a comeback [2]. But how is that possible? The answer is simple. Contrary to popular belief, the AC system might not be better than the DC system, as it has a few drawbacks when it comes to power transmission. One of these drawbacks would be due to the skin effect.

What Is the Skin Effect?

The skin effect is a phenomenon wherein current distribution in a conductor is not uniform when AC flows through it, resulting in power losses [11]. Most of the current would tend to flow on the surface of the conductor, leaving little or no current flowing in the center of the conductor [11]. The current density, 16

which is the current per unit area, would be the highest at the surface of the conductor and decreases with increasing distance from the surface [10]. This effect becomes more apparent with the increase in frequency of the alternating current [10].

Figure 1: [3].

This phenomenon is due to electromagnetic induction. Since an alternating current varies with time, this produces magnetic fields, which change with respect to time [10]. When there are changing magnetic fields, these induce another set of currents in the conductor [10]. These currents converge towards the center of the conductor, opposing the initial current there, while the current flowing at the surface of the conductor is reinforced [9]. This means that the effective cross-sectional area has now been reduced, increasing the conductor’s effective resistance and thus causing power losses [8].

Figure 2: The skin effect [3].

Currents in DC systems do not create another set of currents because the magnetic fields induced by them are not time-variant. As such, DC systems are not impacted by the skin effect.

Experimentation I conducted an experiment to prove the presence of the skin effect and how increasing frequencies could impact it.

A wire prototype was created by adhering the copper wires together, layer by layer, using a glue gun.

A total of three layers were created.

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Figure 3: Layers in wire (own work).

Then, a circuit was created. It consisted of the prototype, a function generator, junction connectors, a 100Ω resistor, and an ammeter.

Figure 4: Methodology (own work).

Then, current readings for the various layers were recorded using the ammeter. The current density (current per unit area) is derived by taking the current reading divided by the layer’s cross-sectional area.

We then plotted a graph using a program in Matlab. We have used Koerner’s code (which models the current density in the conductor with respect to the distance from the center) as a reference, and added additional functions to create the computational model [12].

This experiment was repeated with frequencies of 100 Hz and 300 Hz.

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Results

Figure 5: Graphical results (own work).

From our results, the following can be seen: -

The current density is the highest at the surface of the conductor and decreases with increasing distance from the surface of the conductor.

-

As the frequency increases, the skin effect becomes more apparent, meaning that the current density at the surface becomes much greater compared to the current density at the center.

Current Solutions Thankfully, there are a few ways to mitigate the effects resulting from the skin effect. Tubular conductors, such as pipes, can be constructed. Since the center carries very little current, making the conductor into a tube-like structure by removing the center region of the conductor would conserve the weight and cost of the conductor.

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Figure 6: Tubular wire [4].

Another method would be utilizing the Litz wire. The Litz wire is a conductor made out of some wires insulated from each other, except at the ends where the wires are connected in parallel. To ensure the conductor's effectiveness, each wire strand in the conductor is woven in a certain way. This results in a uniform current distribution in the conductor [7].

Figure 7: Litz wire [5].

These solutions will greatly enhance the efficiency of power transmission and mitigate the skin effect.

Future Solutions Alternatively, alternating current power transmission can be replaced by the ultra-high voltage direct current (UHVDC) system. An example of this implementation can be seen in China.

China’s rapidly-expanding middle class is driving up a relentless demand for electricity. China’s solution was to construct UHVDC systems. AC systems were not chosen as they lose power during transmission. This is due to the current oscillating back and forth, consuming a significant amount of power. For a fixed voltage, an AC system has approximately twice the loss of a DC system. The UHVDC system transmits 6.4 gigawatts from the Xiangjiaba Dam in Sichuan Province to Shanghai, which is almost 2,000 km away, at 800 kilovolts (kV). This is twice the voltage of conventional long-distance systems [6]. To transmit power over several kilometers, a higher voltage is needed.

However, this solution is not a panacea to power transmission and currently has limitations. These stations can be expensive, costing up to $1 billion. There have been plans to construct UHVDC systems to transmit power from wind farms in the North Sea or solar arrays in the desert, but cost makes implementation of the UHVDC system more challenging. Aside from the technical and economic 20

demands, there are also problems of crossing jurisdictional lines and the need to forge agreements among governments and power companies [6]. At the moment, it might not be feasible for countries to use UHVDC systems. However, with the advancement of technology and the development of diplomatic ties, UHVDC systems could be a potential power transmission system standard for countries in the future.

Conclusion In conclusion, the skin effect has the potential to cause significant power losses in AC transmission systems, and there is a potential for DC systems to minimize these losses. Will these systems really make a comeback and be the dominating power system once again? Will there also be another “War of the Currents” in the years to come? That depends on the advancement in science and engineering, and it lies in the hands of our future generation.

Works Cited [1] E. Nix, “What was the War of the Currents?,” HISTORY. [Online].

[2] A. Peshin, “Alternating Current (AC) vs Direct Current (DC). Who Wins?,” Science ABC, 07-Jan-2018. .

[3] “Skin effect,” Wikipedia. 22-Oct-2018.

[4] “Tubular wire.” [Online].

[5] “Litz Wire.” [Online].

[6] “A Powerful Alternative to Alternating Current,” Scientific American. [Online].

[7] F. E. Terman, Radio engineer’s handbook. 1943.

[8] “Skin Effect,” Circuit Globe, 13-Apr-2016. [Online].

[9] admin, “Cause of Skin Effect in AC Conductors,” Electrical Concepts, 05-Sep-2016. .

[10] Z. B. Popović and B. D. Popović, Introductory electromagnetics. 2000.

[11] Casimir and Ubbink, Philips Tech. Review, 1967.

[12] “Skineffect Calculation - File Exchange - MATLAB Central.” [Online].

[13] “Converged Technology Stock Video Footage - 4K and HD Video Clips,” Shutterstock. [Online].

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6. Plant Medicine: Flavonoids and their Role in Inducing Death in Senescent Cells Aleksander Łysomirski, Poland My name is Aleksander Łysomirski and I am a student of the Batory High School, Warsaw, Poland. I am currently on my first year of the International Baccalaureate, which is a globally minded, research-based curriculum that encourages students to engage in many different educational activities. So far, it has impelled me to engage in a research project that encompasses an extremely intriguing part of cytology, namely cellular senescence. This area of research is usually undermined by many scientists but holds great potential for the development of many remedies. Since I have started my research into cellular senescence, it has become one of my favorite aspects of biology. Besides the academic interests, I am a big fan of athletics, especially cross country running.

The population of humankind is constantly rising and so does the average human lifespan. The progression of civilization has led to a dynamic increase in the length of time an individual can be expected to live by eliminating many causes of death that were previously ubiquitous. Initially, the rise was due to improvements in sanitation which helped to combat life-threatening infectious diseases such as cholera or smallpox. A subsequent development of vaccines and antibiotics prompted an even greater decrease in early and mid-life mortality. However, the latest rise in human lifespan can be almost entirely attributed to the development of remedies for age-related diseases that lead to a decreased late-life mortality. In fact, aging cannot be a cause of death itself but is a promoter of diseases such as osteoporosis, atherosclerosis, osteoarthritis, neurodegeneration and cancer. [1] Aging is an integral part of life and will always prevail in all living beings. This is because entropy of the entire universe perpetually increases and therefore deterioration dominates over synthesis. [2] Despite its universal nature the process of aging has not yet been fully described and the question of ‘how do we age’ still remains unanswered. There are a number of theories trying to settle this problem, however the one of cellular senescence is currently the most prevailing. The scientific world has recently favored the idea of rejuvenation of an organism with the use of, so called, senolytic drugs that aim to eliminate senescent cells and therefore alleviate age-related diseases. [3]

What Is Cellular Senescence?

Cellular senescence is a permanent state of cell cycle arrest. A cell in such state is fully active metabolically but does not divide. This phenomemon has been first described by Hayflick and Moorhead

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who observed that cells are not able to grow indefinitely in culture but after a definite number of divisions (which varies among cell types and depends on the conditions of the cell culture) undergo some specific morphological changes. They pass into the state of replicative senescence which is due to telomere shortening. One may wonder why telomeres can determine the cessation of the cell cycle. This is because of a phenomenon known as the “end-replication problem”, which is a result of the removal of a first primer on a strand of DNA during replication. [4] As most somatic cells do not have or have very low activity of telomerase which is responsible for resolving this issue, eventually their telomeres reach a critical length and they can no longer divide. Hayflick therefore deduced that cancer cells which express telomerase do not undergo this process and can divide indefinitely. [5]

Figure 1: β-Gal positive mouse embryonic fibroblasts Cellular senescence can also be caused by other factors than telomere erosion. A cell can undergo stress-induced premature senescence (SIPS) associated with a rapid cell cycle arrest (which in culture takes approximately a few days while it can take weeks or even months for a cell to reach replicative senescence). Furthermore, also oncogenic viruses can cause senescence-associated proliferation arrest. Such phenomenon is called oncogene-induced senescence (OIS). In this case, the type of stress that directly determines the cell cycle arrest is the forced DNA replication. [6]

DNA Damage Response and Its Outcomes DNA damage, especially DNA double-strand breaks (DSBs), can be considered the main trigger of cellular senescence. Such disruption of the genetic material induces a mechanism of DNA damage response (DDR), that consists of multiple signaling pathways leading to either the initiation of DNA repair processes or in case of greater severity of the damage, apoptosis or senescence driving programs. [7] Of particular importance in the DDR is the MRN sensor complex that detects double-strand breaks (DSBs) and contributes to the recruitment and activation of the apical DDR transducer kinase ATM (ataxia telangiectasia mutated) which then with the help of mediator proteins activates an effector kinase Chk2 (checkpoint kinase) that spreads the signal about the DSB through the nucleus. ATM also phosphorylates a histone variant known as H2AX. The phosphorylated histone known as γH2AX plays an important role in chromatin decondensation after DSBs that allows for the subsequent assembly of DDR proteins and therefore determines the latter cascade of events in the DDR. The Chk2 kinase (among other checkpoint kinases) can activate a tumour suppressor protein p53. Upon activation, p53 transcriptionally induces a host of target genes. [8] Via transactivation of CDKN1A gene, which encodes the cyclin dependent inhibitor p21, it can prevent the progression of the cell cycle and therefore promote 23

cellular senescence. However, it can also activate proteins such as p53 upregulated modulator of apoptosis (PUMA) as well as the BH domain proteins Bcl-2 antagonist/killer (Bak) and Bcl-2-associated protein X (Bax), which in turn promote cell death through apoptosis. Both of the outcomes of p53 activation (cellular senescence and apoptosis) are potent tumour suppressive mechanisms, however the way in which they are balanced is still poorly understood. [9] As stated before, cellular senescence is a barrier to cancer development. Bypassing cellular senescence has been shown to result in tumorigenesis. It appears that cells which have mutations in the genes involved in the signaling pathways leading to senescence become cancerous. [10]

Figure 2: The DNA damage response pathway [11].

Hallmarks of Cellular Senescence Many of the components of DDR (which seems to be the most universal signaling pathway in senescent cells) serve as the hallmarks of cellular senescence. Many inhibitors of cyclin-dependent kinases such as p16 and p21 function in the DDR and therefore an increased expression of these proteins characterizes senescent cells. Because of these inhibitors of cyclin dependent kinases senescent cells are arrested in the G1 or G2/M phase of the cell cycle and therefore duplication and segregation of the damaged DNA is prevented. [12] Another hallmark of cellular senescence that can be readily observed under a microscope is the appearance of DNA damage foci that are a result of local accumulation of DDR proteins at DNA damage sites. This is detectable as the phosphorylated histone H2AX which can be stained for with an immunofluorescent antibody. Other than that, senescent cells can be identified by their irregular shape and unnaturally large size; increased granularity; augmented production of reactive oxygen species (ROS) by enlarged and dysfunctional mitochondria; lamin B1 deprived nuclear envelope leading to impaired nuclear integrity and appearance of chromatin fragments in the cytosol and senescence-associated heterochromatin foci (SAHF) which are specialized domains of heterochromatin

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that play a role in silencing of proliferation-promoting genes and therefore determine the permanent cell cycle exit that is representative for senescence. [13] Lastly, the detection of senescent cells can be conducted by tracing the increased activity of lysosomal senescence-associated-b-galactosidase (SA-b-gal). [14] However, this method is not fully specific as increased activity of SA-b-gal also characterizes some overgrown quiescent cells and macrophages. Despite this drawback it is one of the most commonly used markers of senescence. [15] Of particular importance to science is the increased secretory activity of senescent cells termed the senescence-associated secretory phenotype (SASP). This characteristic has a significant impact on the microenvironment of a senescent cell as the factors (cytokines, chemokines, metalloproteinases and growth factors) which the cell secretes induce senescence in bystander cells. SASP can be considered proinflammatory as it creates a chronic sterile low-grade inflammation state. Such chronic inflammation has been proven to cause a range of different age-related pathologies, including cardiovascular diseases, type 2 diabetes and cancer. [16]

Therapy Induced Senescence Primarily, it was thought that anticancer therapeutics results in apoptosis of tumour cells. However, at the beginning of the 21st century it became apparent that at low doses they can induce the state of cellular senescence in cancer cells. This discovery caused great turmoil in the scientific community as it opened new opportunities for cancer therapy, in which smaller amounts of chemotherapeutics could be distributed to patients in order to induce senescence-associated proliferation arrest of cancerous cells and therefore treat cancer. [17] However, in the light of the latest research the perception of senescent cancer cells drastically changed as it became evident that the senescence-associated secretory phenotype (SASP) can propel the development of a pro-inflammatory microenvironment that is favourable for tumorigenesis. The discovery of SASP created a dichotomous view on senescent cells. They can act as a barrier to cancer development but at the same time, through secreting a specific group of factors, they promote tumorigenesis. Interestingly, it appears that senescing of cancer cells is not a one-way process.

Senescent cancer cells have been shown to escape the state of cellular senescence via polyploidization.

This process, which is based on the formation of multiple nuclei of different sizes can be induced in cancer cell by chemotherapeutics such as doxorubicin (Dox). While initially polyploidy was considered a positive response to treatment and cancer cell death, it is now becoming evident that it can lead to cancer renewal as cancer cells with multiple nuclei can give rise to aneuploid or near diploid cells that are able to proliferate. [18]

Flavonoids and Their Role in Eliminating Senescent Cells Since the discovery of the detrimental effects of the secretome of senescent cells, efforts have been made in order to find a way of either eliminating them or suppressing the activity of SASP. There is a growing body of evidence showing that eradicating senescent cells with the use of, so called, senolytics or minimizing the deleterious effect of their secretome by using inhibitors of SASP known as senomorphics can lead to an increased life span and most importantly alleviate age-related diseases therefore contributing to a better quality of life. [20] Developing senotherapeutics is a fairly novel area of research as the first agents exhibiting senolytic activity, dasatinib and quercetin were identified in 2015. Dasatinib is a kinase inhibitor used to treat certain cases of leukemia and quercetin is a common 25

plant flavonoid. Interestingly, further investigation showed that also other flavonoids have a potential of becoming potent senotheraputic agents. [21] Flavonoids are a large group of natural substances with a polyphenolic structure. They belong to a class of plant and fungus secondary metabolites and therefore are commonly found in a plethora of fruits and vegetables. They can also be found in roots, barks, stems, grains etc. Plant flavonoids are well known for their medicinal properties however they are generally found in low, uneven concentrations and thus providing a consistent supply of them is challenging. For a more efficient production of these natural compounds various biotechnological techniques have been tested. The reason for their remarkable effects on health is their ability to regulate some major functions of cellular enzymes and their anti-oxidative, anti-inflammatory, anti-mutagenic and anticarcinogenic properties. Thanks to these features they are biologically and pharmacologically beneficial and have great potential in future treatment of many diseases. Their senolytic acitivity has been proven not only by dasatinib but also by the subsequently identified senotherapeutic that belongs to a group of flavonoids, fisetin. The mechanism of action of these two flavonoids is likely to be associated with PI3K/AKT/mTOR and NF-κB pathway modules. [22] Further research resulted in some intriguing senomorphic activities of flavonoids being recorded. Kaempferol and apigenin were found to have prominent abilities of suppressing SASP which are presumably due to their impeding action in the NF-κB pathway. During the studies into senotherapeutics it has been noticed that senescent cells depend on some specific antiapoptotic and pro-survival pathways. Therefore, targeting components of these pathways allows for the selective elimination of senescent cells or their secretome. A great impediment in developing new senotherapeutic drugs is that their activity is mostly cell-type dependent.

Nonetheless, they hold great potential in the therapy of age-related diseases and cancer. [23]

Figure 3: Immunostaining of nuclear proteins in untreated and dox-treated (senescent) HCT-116 (colon cancer) cells. Nuclei stained with DAPI (blue).

Works Cited [1]M. V. Blagosklonny, “Why human lifespan is rapidly increasing: solving ‘longevity riddle’ with ‘revealed-slow-aging’ hypothesis,” Aging (Albany NY), vol. 2, no. 4, pp. 177–182, Apr. 2010.

[2]L. Hayflick, “Entropy Explains Aging, Genetic Determinism Explains Longevity, and Undefined Terminology Explains Misunderstanding Both,” PLoS Genet, vol. 3, no. 12, Dec. 2007.

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[3]M. Xu et al., “Senolytics Improve Physical Function and Increase Lifespan in Old Age,” Nat Med, vol. 24, no. 8, pp. 1246–1256, Aug. 2018.

[4]B. G. Childs, M. Durik, D. J. Baker, and J. M. van Deursen, “Cellular senescence in aging and age-related disease: from mechanisms to therapy,” Nat Med, vol. 21, no. 12, pp. 1424–1435, Dec. 2015.

[5]P. J. Hornsby, “Telomerase and the aging process,” Exp Gerontol, vol. 42, no. 7, pp. 575–581, Jul. 2007.

[6]T. Kuilman, C. Michaloglou, W. J. Mooi, and D. S. Peeper, “The essence of senescence,” Genes Dev, vol. 24, no. 22, pp. 2463– 2479, Nov. 2010.

[7]J.-H. Chen, C. N. Hales, and S. E. Ozanne, “DNA damage, cellular senescence and organismal ageing: causal or correlative?,” Nucleic Acids Res, vol. 35, no. 22, pp. 7417–7428, Dec. 2007.

[8]G. Giglia-Mari, A. Zotter, and W. Vermeulen, “DNA Damage Response,” Cold Spring Harb Perspect Biol, vol. 3, no. 1, Jan. 2011.

[9]H. C. Reinhardt and B. Schumacher, “The p53 network: Cellular and systemic DNA damage responses in aging and cancer,” Trends Genet, vol. 28, no. 3, pp. 128–136, Mar. 2012.

[10]F. G. Giancotti, “Deregulation of Cell Signaling in Cancer,” FEBS Lett, vol. 588, no. 16, pp. 2558–2570, Aug. 2014.

[11]H. C. Reinhardt and B. Schumacher, “The p53 network: Cellular and systemic DNA damage responses in aging and cancer,” Trends Genet, vol. 28, no. 3, pp. 128–136, Mar. 2012.

[12]G. H. Stein, L. F. Drullinger, A. Soulard, and V. Dulić, “Differential Roles for Cyclin-Dependent Kinase Inhibitors p21 and p16 in the Mechanisms of Senescence and Differentiation in Human Fibroblasts,” Mol Cell Biol, vol. 19, no. 3, pp. 2109–2117, Mar. 1999.

[13]R. Salama, M. Sadaie, M. Hoare, and M. Narita, “Cellular senescence and its effector programs,” Genes Dev, vol. 28, no. 2, pp. 99– 114, Jan. 2014.

[14]B. Y. Lee et al., “Senescence-associated β-galactosidase is lysosomal β-galactosidase,” Aging Cell, vol. 5, no. 2, pp. 187–195, 2006.

[15]D. Holt and D. Grainger, “Senescence and quiescence induced compromised function in cultured macrophages,” Biomaterials, vol. 33, no. 30, pp. 7497–7507, Oct. 2012.

[16]J.-P. Coppé, P.-Y. Desprez, A. Krtolica, and J. Campisi, “The Senescence-Associated Secretory Phenotype: The Dark Side of Tumor Suppression,” Annu Rev Pathol, vol. 5, pp. 99–118, 2010.

[17]B.-D. Chang et al., “Role of p53 and p21 waf1/cip1 in senescence-like terminal proliferation arrest induced in human tumor cells by chemotherapeutic drugs,” Oncogene, vol. 18, no. 34, pp. 4808–4818, Aug. 1999.

[18]G. Mosieniak et al., “Polyploidy Formation in Doxorubicin-Treated Cancer Cells Can Favor Escape from Senescence,” Neoplasia, vol. 17, no. 12, pp. 882–893, Dec. 2015.

[19]“PubMed Central Image Viewer.” [Online]. Available: https://www.ncbi.nlm.nih.gov/core/lw/2.0/html/tileshop_pmc/tileshop_pmc_inline.html?title=Click%20on%20image%20t o%20zoom&p=PMC3&id=4688565_gr2.jpg. [Accessed: 07-Jun-2019].

[20]E.-C. Kim and J.-R. Kim, “Senotherapeutics: emerging strategy for healthy aging and age-related disease,” BMB Rep, vol. 52, no. 1, pp. 47–55, Jan. 2019.

[21]Y. Zhu et al., “The Achilles’ heel of senescent cells: from transcriptome to senolytic drugs,” Aging Cell, vol. 14, no. 4, pp. 644– 658, Aug. 2015.

[22]D. N. Syed, V. M. Adhami, M. I. Khan, and H. Mukhtar, “Inhibition of Akt/mTOR Signaling by the Dietary Flavonoid Fisetin,” Anticancer Agents Med Chem, vol. 13, no. 7, pp. 995–1001, Sep. 2013.

[23]V. Myrianthopoulos, “The emerging field of senotherapeutic drugs,” Future Medicinal Chemistry, vol. 10, no. 20, pp. 2369–2372, Oct. 2018.

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7. The Search for a Cure: The HIV Pandemic Chloe Palumbo, Staples High School ‘19 For decades, HIV, Human Immunodeficiency Virus, has remained one of the most deadly infectious diseases, spreading to 75 million people worldwide [1]. Despite the magnitude of HIV, it still remains a largely ambiguous illness for scientists worldwide. Over the past decade, scientists have conducted a rampant search for cures as the growth of genomics has offered newfound insight behind the microscopic inner workings of HIV. One of the most perplexing topics for scientists concerning HIV was the varying levels of susceptibility among the human population. Professor Stephen O’Brien, a researcher at Harvard School of Public Health, analyzed human genomic composition in an attempt to find the underlying cause of the variable natural genetic resistance to the HIV virus. After extensive research, O’Brien discovered a genetic defect that rendered the CCR5 receptor defective. With a defective CCR5 receptor, the virus has no way of entering the T-cell as it needs to bind with both the CD4 and CCR5 receptor before entering.

Thus, one who inherits the CCR5 defect is genetically resistant to the HIV virus. It’s a very rare defect; however, O’Brien’s discovery laid the foundation for tremendous progress in treating HIV [1].

Shortly after O’Brien’s findings were published, Dr. Gero Hütter hypothesized that selecting bone marrow transplants that were both tissue matches and had the CCR5 defect would be the only viable option for Timothy Ray Brown, one of his patients who suffered from both HIV and Leukemia. Hütter’s bone marrow transplant with the CCR5 defect was a wholly uncharted area in HIV operations. However, Hütter’s revolutionizing idea emerged at the forefront of scientific breakthroughs: in February 2007, Timothy Ray Brown, also known as the Berlin Patient, would become known as the first person to be officially cured of HIV. Hütter’s success and Timothy’s negative HIV results spurred shock and questions in the scientific community [1].

And just recently, two HIV patients who were recently diagnosed with cancer have been cured as a result of similar bone marrow transplants. The first was a London patient who’s been off HIV medication 28

for eighteen months, showing no sign of the virus since. And in March of 2019, a third patient from Düsseldorf, Germany has also been seemingly cured, and has been HIV-free and free of medication for three and a half months [2]. While these patients demonstrate the potential for bone marrow transplants in treating HIV, scientists hesitate to apply similar treatments to the general population.

<CCR5><Entrance> While bone marrow transplants appear to be a potential cure for one of the deadliest infectious diseases, they are difficult to administer and pose a multitude of risks for the average HIV patient. The primary ramifications of bone marrow transplants include the lifelong reliance on immunosuppressive drugs required as well as the risk of Graft-versus-Host disease through which donor immune cells target certain organs, increasing the risk for infection and altering organ function [1]. Given the few instances of patients cured of HIV through bone marrow transplants as well as the repercussions of those procedures, scientists are beginning to look to stem cells as alternative solutions.

In fact, one such experiment conducted by Professor Cannon transplanted mice with newly modified stem cells that contained the genetic defect for the CCR5 gene. After just three months, the HIV infection was essentially eradicated. This experiment provides evidence to the capacity for stem cell application for humans with HIV. Stem cell transplants, unlike bone marrow transplants, are more easily administered and carry much less risk. Furthermore, stem cell transplants are more reliable as the cells constantly replicate, ensuring a more stable supply of negative CCR5 cells [1].

While scientists are yet to declare HIV curable, there are multitudes of promising treatments in the developing stages that could offer some answers. While bone marrow transplants aren’t the most viable options for treating HIV, other options such as stem cell transplants offer more promising and accessible treatments for HIV patients in the future.

Works Cited [1] “Cure for HIV AIDS? Possible but not yet realized,” Hiptoro, 31-Mar-2019. .

[2] R. Rettner, S. W. | March 6, and 2019 05:02pm ET, “Could a Third Person Be Cured of HIV?,” Live Science. [Online].

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8. A Common Anesthetic: Can It Possibly Help Individuals with Post-Traumatic Stress Disorder?

Maya Reiner, Staples High School ‘21 An abundance of Americans battle a serious condition and fatigue syndrome each and every day. Daily, they can feel symptoms of shock, anger, nervousness, fear, and even guilt [1]. It is developed when an individual experienced or witnessed a traumatic event in which serious physical harm occurred or was threatened [1]. This is better known as Post Traumatic Stress Disorder, PTSD, that consumes the lives of 24.4 million people in the United States at any given time [2]. This disease affects many, yet for countless years, there was not much successful treatment for these individuals.

Recent studies, however, indicate there might be effective medicines to reduce the horrible flashbacks and memories that people with PTSD endure. The terrifying thoughts that people with PTSD suffer echo ceaselessly in their minds, and usually, people are incapable to stop these flashbacks. There are two places where the brain remembers things, “When the brain remembers, proteins in two locations deep within the organ—the amygdala and hippocampus—encode the memory until it is stored, or “consolidated” in the vernacular” [3]. Neuroscientists have long believed that once a memory is put in its place, it is permanent and stable.

However, through more recent studies, scientists have discovered that there could be a common anesthetic that could ease the memories and flashbacks that cause PTSD and other stress disorders.

Bryan A. Strange, founder of the Laboratory of Clinical Science at the Universidad Politécnica de Madrid, looked for leads to tamp down toxic memories. They discovered that the anesthetic propofol, if administered correctly, can be used to alter such recollections.

The studies involved implanting memories and then trying to dissolve them, “The researchers enlisted 50 subjects, who, one week before their procedure, were shown an emotionally charged slide show—a boy struck and killed by a car or a woman abducted and molested by an ex-convict” [3]. All of the individuals saw emotionally neutral slideshows as well. Just before they went into their procedure, the individuals were asked to recall those disturbing stories. Then, they received the experimental dose of propofol.

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The researchers tested the memories of some of those patients right after, but knowing that consolidation takes about a day, they did the same assessment 24 hours later. “They found that the anesthetic made no immediate change in memory, but after 24 hours it impaired the memory of the emotionally charged slide show. By the 24-hour mark, reconsolidation had taken place—and the memory of the charged stories was impaired—not gone, but less likely to make the patient suffer” [3].

This study directly correlates to people who suffer from PTSD. This anesthetic functioned just as a PTSD drug should - it impaired the distressing memories, but left the other memories intact. However, there are other ways that PTSD patients are treated; some patients are now treated with exposure therapies, which reactivates the positive and safe memories. That treatment does help some individuals, but proves less effective in more intractable cases, “If propofol is shown in future studies to be effective it could be used for the more difficult cases,” [3]. Although the results of these studies are promising, more research must be conducted before propofol can be widely - and safely - utilized.

Works Cited [1] “Posttraumatic Stress Disorder (PTSD),” WebMD. [Online].

[2] “PTSD Statistics,” Heal My PTSD, 12-May-2009.

[3] P. Raeburn, “A Common Anesthetic Could Ease PTSD and Other Stress Disorders,” Scientific American. [Online].

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9. Does Talking On Your Phone Affect Your Brain’s Metabolism?

Aleksander Stawiarski, Poland I am Aleksander Stawiarski, and an IB Diploma Programme Year 1 student of the Batory High School in Warsaw, Poland. Wanting to investigate the effects of using mobile phones on our health, I have conducted research regarding their influence on protein biosynthesis and stress response in brains in the Nencki Institute of Experimental Biology in Warsaw. My major interests revolve around neurosciences, but I also love rock climbing and contemplating mountain landscapes.

Say you’ve just received a phone call from your best friend who you haven’t talked to for a long time and can’t wait to share some of the freshest updates from your life with. So… You basically end up chatting for 2 hours until your phone runs out of juice. Have you ever wondered how such calls affect your brain? You’ve held your phone against your head for all the time after all. Let me explain…

In our modern world, it seems very peculiar when we hear, that someone doesn’t have a mobile phone. And it’s not even an impression – for May 2019, according to GSMA Intelligence data, there are over 5,12 billon unique mobile phone subscribers in the world [1], making it around 65% of the global population. And the trends are clear – the number of users has grown by 3,72% year-on-year [1].

Therefore, potential health hazards of the mobile phone use are a huge global health issue that needs to be addressed. In this article, I will pertain to the sole physiological consequences, not the psychological or sociological ones.

Mobile phones transmit information on long distances by applying the phenomenon of electromagnetic radiation. The radiation also causes the presence of an electromagnetic field, hence in this article, it will also be regarded as EMF. It can be characterized by its frequency and wavelength (which are inversely proportional to each other), which determine its properties and function in human use.

Our handheld telecommunication devices apply the EMF in its radiofrequency spectrum (hence radiofrequency EMF, or RF-EMF), which usually corresponds to 900 MHz (9 × 108 Hz) or 1800 MHz (1.8 × 109 Hz). According to the Planck-Einstein relation (! = ℎ$;where ! is the energy of a quantum of the radiation, ℎ is the Planck’s constant and $ is the frequency of the radiation), every electromagnetic field/radiation transmits energy with the potential of concentrating in living tissues. Naturally, there are also other factors influencing the levels of absorbed energy, such as the distance between the phone and the user or the extent and type of mobile phone used [3].

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Figure 1: The electromagnetic spectrum in terms of wavelength [2]. Figure 2: Diagram representing the relation of the levels of energy absorbed by a head with the frequency of the electromagnetic field [36].

The interaction of electromagnetic fields with living tissues can either be classified as thermal and non-thermal [Behari, 2008]. The first type is caused by elevation of temperatures in the area of energy absorption as heat and is well ascertained. The second one, however, refers to all kinds of interaction not connected to heat. One of them could be induction of electric currents in the brain by the phenomenon of electromagnetic induction in the membranes of excitable neural cells. This can lead to electrophysiological stimulation (activation or inhibition) of neurons. The described mechanism is used in the technique of transcranial magnetic stimulation (TMS), which is applied in research and therapeutic purposes [4]. Thankfully for us, regular mobile phone users, this doesnâ&#x20AC;&#x2122;t pertain to cell phone radiation, which is much weaker than the one used in TMS and is characterized by different parameters [7]. This shows, however, that the electromagnetic radiation can directly affect brain function in an unobvious way.

Figure 3: Transcranial magnetic stimulation apparatus [38].

Naturally, electric current induction is not the only area of research regarding mobile phone use.

Take cancer, for example. Many studies have been conducted studies pertaining to potential risks of 33

cancerogenesis stemming from exposure to RF-EMF emitted by mobile phones. However though, most of them bring inconclusive results, that often contradict each other. In general, there is neither any consensus, nor unanimous conclusion about RF-EMF and cancer among scientists [9]. Other studies also addressed i.a. nerve cell damage [13]; abnormal glucose metabolism in brain regions close to the antenna of the mobile [3]; oxidative stress in brain [10], [11]; antioxidant defense system disorders [12], male reproductive system pathologies [15].

One way of assessing the influence of electromagnetic fields on human brains is to examine the metabolic changes in the tissues after exposure to the RF-EMF. A topic of particular interest regarding brain health is the protein biosynthesis. Many neurodegenerative diseases in the brain are caused by disturbances in these processes, such as in the case of Alzheimer’s disease connected to the emergence of β–amyloid plaques, caused by protein misfoldings. In order to examine whether exposing oneself to the RF-EMF emitted during a phone call can affect the protein production in a cell, certain marker proteins can be applied.

Heat shock proteins are a family of proteins with various properties and functions. When they were initially discovered, scientists associated them with heat shock exposure of a cell. However though, many other functions have been discovered afterwards: they work as molecular chaperones, assisting protein biosynthesis and post-translational modifications. They take part in the processes of protein folding, degradation targeting, sequestration and scaffolding [17]. The family is known to represent higher expression levels under cellular stress, which make them good markers. Elevated levels of the protein expression may thus indicate that the conditions the cell is subjected to, are highly unfavorable for proper protein biosynthesis and post-translational modifications, or an abundance of flawed proteins targeted for degradation is present.

Because heat shock proteins assist protein folding under unfavorable conditions [18], elevated expression of HSPs can imply higher probability of protein misfoldings or presence of proteins of flawed structure and function. Such instances could lead to cellular process disturbances due to the presence of malfunctional proteins, but also prion generation [19], or accumulation of toxic oligomers and other aggregates.

Available data on HSP responses to non-thermal activation by RF-EMF are often contradictory, but in general, it is considered that the electromagnetic radiation leads to higher levels of expression of heat shock proteins. [21], [22], [23], [24].

However, many studies have led me to some doubt – instead of using real mobile phones to emit radiation, they have applied specific apparatus of very high SAR value. SAR value directly corresponds to the amount of energy absorbed by tissues, expressed in watts per kilogram of tissue (W/kg). Most mobiles don’t exceed 1 W/kg in terms of SAR, however, in the study conducted by Cleary et al. in 1997, the group has exposed material to a field of 25W/kg SAR, which is significantly higher. Moreover, the radiation emitted by phones is not easy to simulate – the modulation of the signal can be very complicated and irregular, whereas electromagnetic fields emitted by “laboratory” generators are very “basic” in their signal – typical, regular sine waves. I wondered, whether the results acquired by the research groups could have been disrupted by not taking the fact into consideration.

I decided to take the matters in my own hands and design my own study. I came up with a procedure, where I exposed rat brain sections kept alive in an incubator (very briefly after the isolation) to RF-EMF emitted by an actual mobile phone conducting a phone call.

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Figure 4 Layout of instruments during the exposure of material to RF-EMF. Own work.

Afterwards, I isolated RNA from the samples and transcribed it onto DNA. Then, I examined the expression of 3 HSP family protein members using quantitative Real-Time PCR reaction.

As a result, it turned out that there is no statistically significant relationship between the expression of any of the examined HSPs and time of exposure to RF-EMF emitted by a mobile phone. In general, this meant that statistically, there is no effect of mobile phone radiation on HSP expression. However, it could clearly be seen from the graphical depiction of data, that the expression of two of the examined proteins grew with time of exposure. Despite their statistical improvability, it could be justified to take the potential correlation into consideration, due to the fact that the times of exposure were short-term and unrepeated, and the number of samples was limited to 3. The latter aspect caused the lack of statistical significance; however, this is a good pilot study, which tested the method for potential further extensions. The visible growth of HSPs level in the cytoplasm with exposure to RF-EMF show that there is much potential in this field of examination and developing the research further would be sensible.

But how could all this happen? How come some low-energy electromagnetic field that is entirely undetectable by our senses stimulate HSP response? I have come up with a model, based on my results and literature which prompts a potential mechanism underlying the seen correlation. RF-EMF has been proven to induce conformational (3D shape) changes of proteins [28]. The three-dimensional shape of proteins determines their biological function, therefore, when it is changed, it can cause disturbances in the proteinâ&#x20AC;&#x2122;s function in the cell. The electromagnetic field emitted by mobiles can also both induce the emergence of reactive oxygen species [11], which can cause damage to not only proteins, but also DNA etc.. Moreover, RF-EMF also disturbs the antioxidant defense system [29], amplifying the negative effect of the previous consequence of radiation exposure. What is also important, a group of scientists [31] stated that that RF-EMF may cause problems in the balance between protein synthesis and degradation. As the cause, they have suggested that the electromagnetic field may interact with hydrogen bonds stabilizing the secondary structure of proteins. All these factors could potentially cause problems in the correct protein biosynthesis and post-translational processes in nervous tissue. Such

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cases could potentially lead to e.g. misfolded protein aggregations, like amyloid-β and Tau in Alzheimer’s disease or islet amyloid polypeptide (IAPP) in type II diabetes [32]. Prions, which cause lethal and incurable neurodegenerative diseases such as Creutzfeld-Jakob’s disease [33], are nothing else than misfolded proteins that have gained infectious properties. Diseases that originate from flawed and abnormal proteins presence are called proteopathies. An example of such a disease may be cataract [34].

So what are the conclusions? Should we worry?

Well, it’s still hard to say. There are many contradictory reports about the negative influence of RFEMF on brain health, and much is still to be learned. But what we do know, is that mobiles radiate the most during phone calls. When you text on WhatsApp, Facebook Messenger or iMessage, the fields emitted don’t transmit as much energy, similarly with casual internet surfing. The trends nowadays suggest a shift away from phone calls via the cellular networks, towards chatting via the Internet. You can also always talk with the speaker mode on, use headphones or wireless headsets designed for phone calls. This should do the job of protecting you from excess exposure to electromagnetic fields.

Bluetooth devices also use RF-EMF, but on much weaker power levels, as they needn’t transmit the information on long ranges [35]. I’d personally suggest being cautious and aware of the potential risks, but without panicking. After all, mobile phones are not portable microwaves of 1000W power, nor do they emit ionizing radiation that could induce mutagenesis in cells. Much is still to be learned about the health consequences of mobile phones use, but if there were any direct and clear threats, we would already have known it for some time. Nevertheless, since it is a crucial issue of public health, it must be addressed by means of more research, that is congeneric, takes various approaches and takes other reports from different fields of study into consideration, as biology is a science, where a comprehensive approach is vital.

Works Cited [1]“GSMA Intelligence.” [Online]. Available: https://www.gsmaintelligence.com/. [Accessed: 27-May-2019].

[2]Cohen-Tannoudji, C., Laloë, F., & Diu, B. , Quantum mechanics. 1990.

[3]N. D. Volkow, “Effects of Cell Phone Radiofrequency Signal Exposure on Brain Glucose Metabolism,” JAMA, vol. 305, no. 8, p. 808, Feb. 2011.

[4]E. M. Wassermann and S. H. Lisanby, “Therapeutic application of repetitive transcranial magnetic stimulation: a review,” Clinical Neurophysiology, vol. 112, no. 8, pp. 1367–1377, Aug. 2001.

[5]S. Groppa et al., “A practical guide to diagnostic transcranial magnetic stimulation: Report of an IFCN committee,” Clinical Neurophysiology, vol. 123, no. 5, pp. 858–882, May 2012.

[6]M. Kobayashi and A. Pascual-Leone, “Transcranial magnetic stimulation in neurology,” The Lancet Neurology, vol. 2, no. 3, pp.

145–156, Mar. 2003.

[7]R. Jalinous, “Technical and Practical Aspects of Magnetic Nerve Stimulation:,” Journal of Clinical Neurophysiology, vol. 8, no. 1, pp. 10–25, Jan. 1991.

[8]World Health Organization, “IARC Classifies Radiofrequency Electromagnetic Fields as Possibly Carcinogenic to Humans,” May 2011.

[9]Scientific Committee on Emerging and Newly Identified Health Risks, “Potential health effects of exposure to electromagnetic fields (EMF).”

[10]S. Dasdag and M. Z. Akdag, “The link between radiofrequencies emitted from wireless technologies and oxidative stress,” Journal of Chemical Neuroanatomy, vol. 75, pp. 85–93, Sep. 2016.

[11]I. Meral et al., “Effects of 900-MHz electromagnetic field emitted from cellular phone on brain oxidative stress and some vitamin levels of guinea pigs,” Brain Research, vol. 1169, pp. 120–124, Sep. 2007.

[12]E. Kivrak, K. Yurt, A. Kaplan, I. Alkan, and G. Altun, “Effects of electromagnetic fields exposure on the antioxidant defense system,” Journal of Microscopy and Ultrastructure, vol. 5, no. 4, p. 167, 2017.

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[13]L. G. Salford, A. E. Brun, J. L. Eberhardt, L. Malmgren, and B. R. R. Persson, “Nerve cell damage in mammalian brain after exposure to microwaves from GSM mobile phones.,” Environmental Health Perspectives, vol. 111, no. 7, pp. 881–883, Jun. 2003.

[14]B. Deepti, “Electromagnetic Hypersensitivity Syndrome,” International Journal on Green Pharmacy.

[15]N. R. Desai, K. K. Kesari, and A. Agarwal, “Pathophysiology of cell phone radiation: oxidative stress and carcinogenesis with focus on male reproductive system.,” Reprod Biol Endocrinol, 2009.

[16]J. Behari, “Mobile phone frequency exposure and human health,” (:unav), Nov. 2008.

[17]R. A. Stetler et al., “Heat shock proteins: Cellular and molecular mechanisms in the central nervous system,” Progress in Neurobiology, vol. 92, no. 2, pp. 184–211, Oct. 2010.

[18]A. Blanco and G. Blanco, Medical biochemistry. London, United Kingdom ; San Diego, CA: Academic Press, an imprint of Elsevier, 2017.

[19]H.-Y. Lian, K.-W. Lin, C. Yang, and P. Cai, “Generation and propagation of yeast prion [URE3] are elevated under electromagnetic field,” Cell Stress and Chaperones, vol. 23, no. 4, pp. 581–594, Jul. 2018.

[20]N. Gregersen, P. Bross, S. Vang, and J. H. Christensen, “Protein Misfolding and Human Disease,” Annual Review of Genomics and Human Genetics, vol. 7, no. 1, pp. 103–124, Sep. 2006.

[21]D. Leszczynski, S. Joenväärä, J. Reivinen, and R. Kuokka, “Non‐thermal activation of the hsp27/p38MAPK stress pathway by mobile phone radiation in human endothelial cells: Molecular mechanism for cancer‐ and blood‐brain barrier‐related effects,” Differentiation, vol. 70, no. 2–3, 2002.

[22]S. F. Cleary, G. Cao, L. M. Liu, P. M. Egle, and K. R. Shelton, “Stress proteins are not induced in mammalian cells exposed to radiofrequency or microwave radiation.,” Bioelectromagnetics, vol. 18, no. 7, pp. 499–505, 1997.

[23]K. Balakrishnan et al., “Hsp70 Is an Independent Stress Marker Among Frequent Users of Mobile Phones,” Journal of Environmental Pathology, Toxicology and Oncology, vol. 33, no. 4, pp. 339–347, 2014.

[24]D. Weisbrot, H. Lin, L. Ye, M. Blank, and R. Goodman, “Effects of mobile phone radiation on reproduction and development in Drosophila melanogaster,” Journal of Cellular Biochemistry, vol. 89, no. 1, pp. 48–55, May 2003.

[25]J. Kiang, “Heat Shock Protein 70 kDa Molecular Biology, Biochemistry, and Physiology,” Pharmacology & Therapeutics, vol. 80, no. 2, pp. 183–201, Nov. 1998.

[26]C. Gerner et al., “Increased protein synthesis by cells exposed to a 1,800-MHz radio-frequency mobile phone electromagnetic field, detected by proteome profiling,” International Archives of Occupational and Environmental Health, vol. 83, no. 6, pp.

691–702, Aug. 2010.

[27]A. Karinen, S. Heinavaara, R. Nylund, and D. Leszczynski, “Mobile phone radiation might alter protein expression in human skin,” BMC Genomics, vol. 9, no. 1, p. 77, 2008.

[28]M. Blank, “Protein and DNA Reactions Stimulated by Electromagnetic Fields,” Electromagnetic Biology and Medicine, vol. 27, no. 1, pp. 3–23, Mar. 2008.

[29]E. Kivrak, K. Yurt, A. Kaplan, I. Alkan, and G. Altun, “Effects of electromagnetic fields exposure on the antioxidant defense system,” Journal of Microscopy and Ultrastructure, vol. 5, no. 4, p. 167, 2017.

[30]R. M. Vabulas, S. Raychaudhuri, M. Hayer-Hartl, and F. U. Hartl, “Protein Folding in the Cytoplasm and the Heat Shock Response,” Cold Spring Harbor Perspectives in Biology, vol. 2, no. 12, pp. a004390–a004390, Dec. 2010.

[31]C. Gerner et al., “Increased protein synthesis by cells exposed to a 1,800-MHz radio-frequency mobile phone electromagnetic field, detected by proteome profiling,” International Archives of Occupational and Environmental Health, vol. 83, no. 6, pp.

691–702, Aug. 2010.

[32]A. S. DeToma, S. Salamekh, A. Ramamoorthy, and M. H. Lim, “Misfolded proteins in Alzheimer’s disease and type II diabetes,” Chem. Soc. Rev., vol. 41, no. 2, pp. 608–621, 2012.

[33]G. Mackenzie and R. Will, “Creutzfeldt-Jakob disease: recent developments,” F1000Research, vol. 6, p. 2053, Nov. 2017.

[34]H. Ecroyd and J. A. Carver, “Crystallin proteins and amyloid fibrils,” Cellular and Molecular Life Sciences, vol. 66, no. 1, pp. 62–81, Jan. 2009.

[35]S. Wall, Z. M. Wang, T. Kendig, D. Dobraca, and M. Lipsett, “Real-world cell phone radiofrequency electromagnetic field exposures.,” Environ Res., no. 171, pp. 581–592, Apr. 2019.

[36]“Electric field.” [Online].

[37]D. Pimienta-Del Valle and R. Lagar-Pérez, “Design of a Dual-Band PIFA for Handset Devices and it SAR Evaluation,” Ingeniería, Investigación y Tecnología, vol. 17, no. 2, pp. 169–178, Apr. 2016.

[38]“Transcranial magnetic stimulation - Mayo Clinic.” [Online].

[39]“Cell Phones and Cancer Risk,” National Cancer Institute, 14-Jan-2019. [Online].

[40]“Electromagnetic Spectrum - Principles of Structural Chemistry.” [Online].

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10. Huntington’s Disease Paul Mark Tammiste, Estonia I'm Paul Mark Tammiste from Estonia and I study in 11th grade in Tallinn Secondary School of Science.

When I first got the proposal of doing a molecular biology research in neuroscience I was like a small boy dancing around in joy in a candy shop. My research analyzes how transcription factors can play a crucial role in neurology, especially in Huntington's disease. Besides my love for biology, chemistry and mathematics, I am no foreigner to Shakespeare, Émile Zola or Bukowski: folks, read literature!

Literature Overview Huntington’s disease (HD) is a fatal neurodegenerative disease, affecting one person in every 20,000 [1].

It is a genetic disorder caused by a mutation in the autosomal-dominant Huntingtin gene [1; 2]. Patients of HD suffer from lack of coordination, unsteady gait, and jerky body movements [1; 2]. Many patients also have problems with their mood and risk developing dementia [1; 2]. The age of onset is undefinable, but it usually appears in a person's thirties or forties [1; 2]. HD is characterized by the loss of striatal neurons -- which play a crucial role in motor and reward systems -- due to the expansion of the CAG trinucleotide repetition in the first exon of the huntingtin gene. Normal cells have less than 35 CAG repeats. The excess number of CAG repeats in the Huntingtin gene produces the Huntingtin protein with a long poly-glutamine chain in it. Due to this chain, mutant Huntingtin proteins start to interact with molecules in the cell with which normal Huntingtin proteins would not. This results in a disruption of intracellular localization of transcription factors, such as sterol regulatory element binding protein (SREBP)[3], involved in lipid homeostasis, and repressor element 1 silencer of transcription (REST/NRSF) [4], which regulates synaptic plasticity and promotes neuroprotection. This is the central reason as to why Huntington’s disease is degenerative -- these transcription factors play a crucial role in neuron development and homeostasis, and due to the disruption of normal transcription pathways, neurons die.

Transcription factor 4 (TCF4) is another transcription factor important in neural systems. Due to its structure, it can interact both with other transcription factors and directly with DNA [5]. TCF4 plays a crucial role in a fetus’ neurological development[5]. Mutations in TCF4 have been associated with PittHopkins Syndrome, intellectual disability, schizophrenia, and bipolar disease [5]. Considering the importance of TCF4 in the nervous system and the similar symptoms of anormal TCF4 and Huntington’s disease, one can question whether Huntington’s disease affects subcellular localization of TCF4.

Methodology In my research, immunocytochemistry (ICC) was used to study subcellular localization of TCF4. ICC is a laboratory method that uses antibodies to analyze an antigen’s anatomical location within a cell; in the context of this project, the scrutinized antigen was TCF4. The antibodies are conjugated with 38

fluorophores, which emit light under a fluorescent microscope. There are two main methods: direct and indirect [Fig. 2]. In the direct method, antibodies with fluorophores bind directly to the antigen. With the indirect method, primary antibodies bind to the antigen and secondary antibodies containing fluorophores bind to the primary antibodies. The latter method was used in this study, as more fluorophores are bound with one antigen, achieving stronger signalling. Three different TCF4-specific antibodies, with various dilutions, were used to identify the location of TCF4: CeMines, Derek Blake (DB) and Santa Cruz (SC). Localization of TCF4 was studied in specially-derived striatal mouse cell lines that express either normal or mutant huntingtin with 7 or 109 CAG trinucleotide repeats in either one or both alleles (Hdh 7/7, Hdh 7/109, Hdh 109/109). HD is a dominant disease, therefore Hdh 7/109 and Hdh 109/109 cells present the disease, and Hdh 7/7 presents a healthy cell.

Figure 1. The brain on the top has HD and the brain on the bottom is normal. Atrophy of the basal ganglia clearly exhibits the effects of HD [6].

Figure 2. Direct and indirect immunocytochemistry methods are shown. The signal with the direct method may be weak, as one antibody can be conjugated with only one fluorophore. In order to get a stronger visual, indirect methods must be used [7].

Results and Analysis Results in a 1:100 dilution can be seen in Figure 3. Based on the TCF4 images, it is possible to determine whether the location of TCF4 differs in various cell types in one antibody. DNA and tubulin pictures are used to help visualize the general structure of the cell. Both CeMines and SC show distribution of TCF4 relatively equally in all cell lines, while DB visualizes TCF4 mainly in the nuclei. TCF4 signals in the

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cytoplasm (seen in CeMines and SC pictures) are most likely caused by non-specific antibody binding or by insufficient blocking. Blocking is a process in which nonspecific proteins are blocked in order to prevent antibodies from interacting with them. Weak TCF4 nuclear signal in the CeMines pictures may be due to insufficient permeabilization or simply lack of localization in the nucleus. Permeabilization is a process in which a membrane is made permeable to allow antibodies into the cell or nucleus.

Permeabilization should not be the problem, however, as other cells with different antibodies were permeabilized with the same substance, concentration, and time. Therefore, CeMines is not the best antibody to visualize TCF4 distribution in the cell. Though three different antibodies with the same concentrations visualize localization of TCF4 differently in one cell type, the location of TCF4 does not change among these types.

Therefore, Huntington’s disease does not affect localization of TCF4.

Conclusion

Figure 3. Each column corresponds with one specific antibody. In the images, TCF4 is visualized in green, nuclei (DNA) are blue, and tubulin (cytoskeleton) is depicted in red. The results are given in three major categories: Hdh 7/7, Hdh 7/109 and Hdh 109/109.

Hdh 7/7 is a healthy cell type, while Hdh 7/109 and 109/109 have HD.

Huntington’s disease is a neurodegenerative disease caused by a mutation in the Huntingtin gene. The resulting abnormal Huntingtin protein interacts with transcription factors in the cell, which inhibits a normal molecular bio-system of the cell. Transcription factor 4 is a protein that plays a crucial role in fetus neurological development; its dysfunction can lead to Pitt-Hopkins Syndrome, intellectual disability, schizophrenia and bipolar disease. Although at first glance, it may seem as though TCF4 is correlated to the symptoms of Huntington’s disease due to its importance within the nervous system, this research determined no such connection. Based on immunocytochemistry analysis with three antibodies, no change was detected in TCF4’s location. From these findings, it is possible to conclude that Huntington’s disease does not affect the localization of TCF4.

Huntington’s disease is but one of the many diseases in which molecular mechanisms are yet to be determined. Finding the answers to such problems starts from dividing the problem into small questions. And nowadays, in science, it is vital to ask the right questions if we ever hope to find the solutions.

Works Cited

[1] “Huntington disease,” Genetics Home Reference. [Online].

[2] R. H. Myers, “Huntington’s disease genetics,” Neurotherapeutics, vol. 1, no. 2, pp. 255–262, Apr. 2004.

[3] M. Valenza, “Dysfunction of the Cholesterol Biosynthetic Pathway in Huntington’s Disease,” Journal of Neuroscience, vol. 25, no.

43, pp. 9932–9939, Oct. 2005.

[4] C. Zuccato et al., “Huntingtin interacts with REST/NRSF to modulate the transcription of NRSE-controlled neuronal genes,” Nature Genetics, vol. 35, no. 1, pp. 76–83, Sep. 2003.

[5] M. P. Forrest, M. J. Hill, A. J. Quantock, E. Martin-Rendon, and D. J. Blake, “The emerging roles of TCF4 in disease and development,” Trends in Molecular Medicine, vol. 20, no. 6, pp. 322–331, Jun. 2014.

[6] “Untitled.” [Online]. Available: http://kobiljak.msu.edu/CAI/Pathology/Degen_F/Degen_2c.html.

[7] “Sample Preparation for Fluorescence Microscopy: An Introduction - Concepts and Tips for Better Fixed Sample Imaging Results | July 28, 2015.” [Online].

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11. Eat Your Fruits and Veggies: AMP-Activated Protein Kinaseâ&#x20AC;&#x201D;The Energy Sensor in the Cell and its Activators Barbara Walkowiak, Poland My name is Barbara, I live in Warsaw in Poland and I am in 11th grade. I am interested in biochemistry and medicine, especially metabolic disorders. In my research I would like to examine the impact of certain nutrients on key metabolic enzymes, such as AMPK. Besides academia, I am passionate about theater and participate in the theater club at my school. I also practice sports and try to self-study Chinese.

Protein Modifications and the Role of Kinases Proteins are macromolecules essential for the cell to perform all functions of life. Their roles range from receiving signals from the cell and the environment, to providing structure, to transporting nutrients in the organism. For proteins to perform their functions properly, very often they need to undergo posttranslational modifications (PTMs) - chemical changes to the proteins that happen after the protein is synthesized and that result in an active form of the protein. One of the most important and most common PTMs is phosphorylation, a reversible mechanism of joining a phosphate group (PO4) to proteins, specifically to polar amino acids in their side chain (R group), mostly serine (86.4% of all cases of phosphorylation) and threonine (11.8]%) [1] Phosphorylation is well-established as a very abundant and common mechanism of protein modification in the cell; approximately 70% of proteins encoded in the human genome are confirmed to undergo phosphorylation with another 20% are considered likely to be phosphorylated [1]. Taking into account the abundance of phosphorylation events in the cell and its multiple effects, there is a mounting empirical evidence that excess or deficient events of phosphorylation might contribute to many significant diseases [2], such as cancer and diabetes [3]. But how can proteins become phosphorylated? This process is performed by a special class of enzymes called protein kinases. So far, scientists have identified over 550 kinases encoded in the human genome, which indicates their abundance and importance in maintaining the homeostasis in the cell [4]. One of the most studied kinases is protein kinase activated by AMP (AMPK). It is present in almost all eukaryotes, in which it displays a high degree of evolutionary conservation, such as a highly conserved core [5], which suggests its importance in the maintenance of cell homeostasis.

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Energy Balance in the Cell and the Importance of AMPK One of the most essential functions that is needed to maintain balance in the cell and in the organism as a whole is regulation of energy consumption and expenditure. A considerable amount of ATP present in the cell demonstrates high levels of energy. The ATP may be used to synthesize proteins or fats, or perform other anabolic processes, which may vary depending on the type if tissue. During anabolic processes, a phosphate group is removed from ATP, resulting in ADP, and, if the second phosphate group is removed, AMP. If there is too much AMP in the cell, it is a sign that the energy levels are low and there is a need to produce more energy through catabolism. In this step, AMPK comes into play. This kinase is activated by AMP molecules (and also, as was recently discovered, by ADP) and so detects the level of energy in the cell. In its active form, AMPK activates catabolic pathways and inhibits anabolic pathways, resulting in ATP production. Therefore, AMPK is very often called an energy switch which, through phosphorylation of certain proteins, may control cell growth, metabolism of glucose and lipids, and other essential biological processes. Moreover, AMPK allows the cell to respond to energetic stress during the period of decreased nutrients supply [6]. Its central role in the metabolic processes that take place in the cell include increasing glucose uptake, fatty acid oxidation, biogenesis of mitochondria, while suppressing anabolic processes, such as synthesis of cholesterol and proteins.

Figure 1: [19].

Structure of AMPK AMPK is a serine- threonine heterotrimeric kinase formed of three subunits (alfa, beta, gamma) present in the mass ratio 1:1:1, out of which the α subunit is the catalytic one, and β and γ are regulatory, the βsubunit being also referred to as structurally crucial. The subunits may occur in different isoforms that are encoded by different genes and are tissue-specific. AMPK is activated through phosphorylation of the 172th residue of threonine, usually referred to as Thr172, in the α subunit [16].

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Figure 2: [20].

AMPK as a Target in Therapy So far, we know that activating AMPK results in increasing fatty acids oxidation and improved glucose uptake, while it decreases the level of protein synthesis and reduces the level of fat synthesis. Doesnâ&#x20AC;&#x2122;t it seem then as a good target in treating metabolic syndrome and related diseases, such as insulin resistance, diabetes and hypercholesterolemia or obesity? Essentially, a decrease in AMPK activation was associated with metabolic syndrome. The association is based on the observation that AMPK activation in white adipose tissue is significantly reduced in humans affected by insulin resistance and diabetes. The proposed mechanism suggests that excess sugar or fat consumption and lack of physical exercise, coupled with genetic factors that increase the risk of metabolic diseases, lead to early pathogenic events, one of which is the decrease in AMPK activation, which in turn leads to hyperinsulinemia and insulin-resistance, which often pre-date hypertension or type 2 diabetes [8].

AMPK Activators Fortunately, there are many natural and synthetic compounds that activate AMPK, called, simply enough, AMPK activators. These can be divided into two groups: direct and indirect. The first group acts by mimicking the structure of AMP that allows them to bind to AMPK and activate the enzyme, while compounds from the second group increase the count of AMP molecules in the cell, creating more AMP to activate AMPK. One of the most widely known AMPK activators is a first-line type 2 diabetes drug called metformin, a derivative of guanidine [22]. However, prevention is always better than cure, and so there is a growing interest in natural substances present in food that may increase the activity of AMPK. The first group of natural substances that exhibit such activity is widely present in plants. Most phytochemicals, mainly polyphenols, are indirect AMPK activators. Well known examples include resveratrol, which can be found in grapes, quercetin from kale and red onions, and curcumin- the pigment responsible for the beautiful yellow color of turmeric. Polyphenols act through inhibiting mitochondrial action and thus decreasing production of ATP, which leads to accumulation of AMP and an increase in the AMP to ATP ratio.

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Figure 3: AMPK activators [21].

If you are interested in nutrition, you probably have heard of antioxidants- substances that scavenge oxygen-free radicals and prevent them from damaging lipids and proteins in your cells. Overabundance of free radicals is a major stressor for the body. Despite their negative effects on health, some studies show that they may also activate AMPK. This hypothesis has recently gained attention and is expected to shed light on the role of AMPK in cancer and cell senescence. One of the most commonly known antioxidants is vitamin C, a compound of great importance to the human body. Vitamin C is thought to improve immunity functioning, increase iron absorption, and regulate collagen synthesis, which makes it an important molecule in the process of wound healing as well as the maintenance of bones and cartilage [9]. Whatâ&#x20AC;&#x2122;s more, it has recently been established that vitamin C may also play an important role in regulating the energy balance through activating AMPK. You may think that due to the prevalence of vitamin C, it is impossible to develop a deficiency; however, a few studies found that globally, vitamin C deficiency is much more common than many people would expect. The results from a study in an Indian population showed that 73.9 % people in North India and 45.7% in South India were deficient in vitamin C [10]. Another study based in the United States [11] showed that more than 10% of the population was deficient in vitamin C, with low-income persons and tobacco smokers being at higher risk. Although these groups display highest risks of developing vitamin C deficiency, a study among non-smoking Canadians found that only 53% of them had adequate levels of vitamin C [12]. Also, in patients who suffer from metabolic diseases that could be a result of a highly processed, unhealthy diet, the levels of vitamin C may be too low.

Interestingly, it was found that subjects suffering from vitamin C deficiency had also significantly higher waist circumference, body mass index, and blood pressure. In fact, vitamin C has been connected to metabolism through observations of its deficiency contributing to an increased risk of obesity and fat deposition. Vitamin C intake is negatively correlated with the occurrence of cardiovascular events and metabolic diseases, including hypertension, diabetes, stroke, atherosclerosis [13] and obesity. Also, increased intake of vitamin C was shown to reduce the risk of type 2 diabetes [14], both by acting as an antioxidant and as a mediator of insulin resistance [WP15].

Whatâ&#x20AC;&#x2122;s the Conclusion?

A diet rich in plants is one crucial key to maintaining health and well-being. Specific compounds present in plants, such as polyphenols and antioxidants, are not only conducive for healthy weight

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maintenance, but may also help inhibit lipogenesis in fat tissue and improve response to glucose. Also, plant extracts may act as a support for treatment of patients suffering from metabolic diseases.

Works Cited [1]F. Ardito, M. Giuliani, D. Perrone, G. Troiano, and L. L. Muzio, “The crucial role of protein phosphorylation in cell signaling and its use as targeted therapy (Review),” International Journal of Molecular Medicine, vol. 40, no. 2, pp. 271–280, Aug. 2017.

[2]S. Marmiroli, D. Fabbro, Y. Miyata, M. Pierobon, and M. Ruzzene, “Phosphorylation, Signaling, and Cancer: Targets and Targeting,” BioMed Research International, vol. 2015, pp. 1–3, 2015.

[3]E. G. Krebs and J. T. Stull, “Protein phosphorylation and metabolic control,” Ciba Found. Symp., no. 31, pp. 355–367, 1975.

[4]D. Fabbro, S. W. Cowan-Jacob, and H. Moebitz, “Ten things you should know about protein kinases: IUPHAR Review 14,” Br J Pharmacol, vol. 172, no. 11, pp. 2675–2700, Jun. 2015.

[5]A. Jain, V. Roustan, W. Weckwerth, and I. Ebersberger, “Studying AMPK in an Evolutionary Context,” in AMPK, vol. 1732, D. Neumann and B. Viollet, Eds. New York, NY: Springer New York, 2018, pp. 111–142.

[6]S. Herzig and R. J. Shaw, “AMPK: guardian of metabolism and mitochondrial homeostasis,” Nature Reviews Molecular Cell Biology, vol. 19, no. 2, pp. 121–135, Oct. 2017.

[7]D. Martin-Hidalgo, A. Hurtado de Llera, V. Calle-Guisado, L. Gonzalez-Fernandez, L. Garcia-Marin, and M. Bragado, “AMPK Function in Mammalian Spermatozoa,” International Journal of Molecular Sciences, vol. 19, no. 11, p. 3293, Oct. 2018.

[8]N. B. Ruderman, D. Carling, M. Prentki, and J. M. Cacicedo, “AMPK, insulin resistance, and the metabolic syndrome,” Journal of Clinical Investigation, vol. 123, no. 7, pp. 2764–2772, Jul. 2013.

[9]V. Camarena and G. Wang, “The Epigenetic Role of Vitamin C in Health and Disease,” Cell Mol Life Sci, vol. 73, no. 8, pp. 1645– 1658, Apr. 2016.

[10]L. Maxfield and J. S. Crane, “Vitamin C Deficiency (Scurvy),” in StatPearls, Treasure Island (FL): StatPearls Publishing, 2019.

[11]R. L. Schleicher, M. D. Carroll, E. S. Ford, and D. A. Lacher, “Serum vitamin C and the prevalence of vitamin C deficiency in the United States: 2003–2004 National Health and Nutrition Examination Survey (NHANES),” The American Journal of Clinical Nutrition, vol. 90, no. 5, pp. 1252–1263, Nov. 2009.

[12]L. Cahill, P. N. Corey, and A. El-Sohemy, “Vitamin C Deficiency in a Population of Young Canadian Adults,” American Journal of Epidemiology, vol. 170, no. 4, pp. 464–471, Aug. 2009.

[13]C. S. Johnston, B. L. Beezhold, B. Mostow, and P. D. Swan, “Plasma Vitamin C Is Inversely Related to Body Mass Index and Waist Circumference but Not to Plasma Adiponectin in Nonsmoking Adults,” The Journal of Nutrition, vol. 137, no. 7, pp. 1757–1762, Jul. 2007.

[14]C. Zhou et al., “Dietary Vitamin C Intake Reduces the Risk of Type 2 Diabetes in Chinese Adults: HOMA-IR and T-AOC as Potential Mediators,” PLOS ONE, vol. 11, no. 9, p. e0163571, Sep. 2016.

[15]A. Mosdol, B. Erens, and E. J. Brunner, “Estimated prevalence and predictors of vitamin C deficiency within UK’s low-income population,” Journal of Public Health, vol. 30, no. 4, pp. 456–460, Dec. 2008.

[16]R. G. Kurumbail and M. F. Calabrese, “Structure and Regulation of AMPK,” in AMP-activated Protein Kinase, vol. 107, M. D. Cordero and B. Viollet, Eds. Cham: Springer International Publishing, 2016, pp. 3–22.

[17]D. G. Hardie, “AMP-activated protein kinase: the guardian of cardiac energy status,” Journal of Clinical Investigation, vol. 114, no. 4, pp. 465–468, Aug. 2004.

[18]D. Martin-Hidalgo, A. Hurtado de Llera, V. Calle-Guisado, L. Gonzalez-Fernandez, L. Garcia-Marin, and M. Bragado, “AMPK Function in Mammalian Spermatozoa,” International Journal of Molecular Sciences, vol. 19, no. 11, p. 3293, Oct. 2018.

[19]“The Energy-Boosting, Hormone-Balancing Enzyme You Need to Know About,” Dr. Axe. [Online]. Available: https://draxe.com/ampk/. [Accessed: 27-May-2019].

[20]Y.-W. Wang et al., “Metformin: a review of its potential indications,” Drug Des Devel Ther, vol. 11, pp. 2421–2429, Aug. 2017.

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12. The Protein Paradox Derek Ye, Staples High School ‘21 When was the last time that you ate protein? Maybe that hamburger for lunch, or those eggs for breakfast? Chances are it’s at least within the last few days. All animals must eat protein regularly to survive because we cannot make protein out of fat, carbohydrates, or cholesterol. Since we can’t simply make proteins from scratch, and our bodies cannot store excess protein, it is “the only macronutrient that we absolutely must eat regularly in order to thrive” [1]. But how does this protein form in the first place? For those who have taken basic biology, you may recall that there are 4 levels to protein folding.

The primary structure and linear amino-acid sequence of a protein determine its native conformation.

The secondary structure contains alpha helices and beta sheets due to intramolecular hydrogen bonds.

The tertiary structure occurs due to bonding within the R groups of a protein, and the quaternary structure is where polypeptide chains interact with each other, forming a fully functional quaternary protein. However, this spontaneous process may be much more complicated than we know. In this article, I will discuss some exceptions to this common knowledge, from Levinthal’s paradox to Anfinsen's dogma, as well as describing chaperone proteins working throughout the cells of our bodies.

Levinthal’s Paradox Levinthal’s paradox was a thought experiment designed by Cyrus Levinthal in 1969. Levinthal discovered that, due to a large number of degrees of freedom in an unfolded polypeptide chain, such a molecule has an astronomically large number of possible conformations. In fact, an estimate of 3100 or 10143 was made in one of his papers [2]! It was calculated that if a protein were to reach its correctly folded configuration by sampling all possible combinations in sequence, it would need longer than the age of the universe to arrive at the correct conformation, even if one trillion combinations were tested every second. Levinthal’s “paradox” was that most proteins fold spontaneously, on a millisecond time scale.

Being aware of this, he hypothesized that this paradox could be resolved only if “protein folding is sped up and guided by the rapid formation of local interactions which then determine the further folding of the peptide” [3]. Basically, he suggested that local amino acid sequences which form stable interactions serve as the starting point of the folding process. His hypothesis proved to be correct: partially folded states have been detected in experiments, helping to explain the speed at which proteins fold.

Anfinsen's Dogma Anfinsen’s dogma, also known as the thermodynamic hypothesis, states that for small globular proteins in a standard, physiological environment, the native structure is determined only by the protein’s amino acid sequence, or its primary structure [4]. This dogma was created by Christian B. Anfinsen in 1973, and 46

helped him earn a Nobel Prize on his research on the folding of ribonuclease A. His postulate states that at the environmental conditions at which folding occurs, the native structure is a unique, stable, and kinetically accessible minimum of free energy. Uniqueness means that the sequence does not have any other configuration with a similar amount of free energy, stability means that small changes in the environment cannot create changes in the minimum configuration, and kinetical accessibility means that the folding of the chain must not have complex changes. How the protein reaches its structure is called protein folding, which ties back to Levinthal’s paradox. However, there are two main proteins that must also be explored as an exception to this rule: chaperone proteins and prions.

Chaperone Proteins Some proteins require the assistance of other proteins to fold properly. This is where chaperone proteins come into play. They assist in the covalent folding or unfolding, as well as the assembly or disassembly of other macromolecular structures. One of their major functions is to prevent new polypeptide chains and assembled subunits from clumping up and forming a nonfunctional structure.

Although not all chaperone proteins are heat shock proteins, a large percentage of them are, as proteins tend to get bent out of shape as temperature increases. Many researchers have come to believe that these chaperone proteins’ existence disproves Anfinsen’s dogma; however, they do not seem to affect the final state of the protein. Since they only prevent the aggregation of protein molecules before the final, folded state of a protein, an argument can be made for both sides. What do you think?

Prions The term prion stands for proteinaceous infectious particle [5]. Discovered during the 1960s by Tikvah Alper and John Stanley Griffith, they seem to be the only definitive exception of Anfinsen’s dogma: stable forms of proteins different from the native folding shape. Prions are thought to cause many diseases in humans affecting the brain or other neural tissues (e.g. mad cow disease). This is because prion aggregates are stable, accumulate in infected tissues, and are often associated with tissue damage and cell death. Their stability makes them resistant to denaturation by chemical and physical agents, making it very difficult to dispose of them. There are no known effective treatments, and these diseases are always fatal. This misfolding once again contradicts our current understanding of proteins.

A Modification in Mind From our textbooks to the food on our plates, proteins seem to be everywhere; our basic understanding of such an essential part of life appears to be rather bizarre. So the next time you take a moment and realize how proteins are folded, take into account the exceptions and differences to the rules at hand.

Works Cited [1] “Protein,” Diagnosis:Diet. .

[2] “Levinthal’s Paradox,” 23-May-2011. [Online]. Available: https://web.archive.org/web/20110523080407/http://wwwmiller.ch.cam.ac.uk/levinthal/levinthal.html. [Accessed: 28-May-2019].

[3] M. Rooman, Y. Dehouck, J. M. Kwasigroch, C. Biot, and D. Gilis, “What is Paradoxical about Levinthal Paradox?,” Journal of Biomolecular Structure and Dynamics, vol. 20, no. 3, pp. 327–329, Dec. 2002.

[4] C. B. Anfinsen, “Principles that Govern the Folding of Protein Chains,” Science, vol. 181, no. 4096, pp. 223–230, Jul. 1973.

[5] S. B. Prusiner, “Novel proteinaceous infectious particles cause scrapie,” Science, vol. 216, no. 4542, pp. 136–144, Apr. 1982.

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