Fall 2008 Issue

sc1ent1ficcarolina Undergraduate Magazine UNC-Chapel Hill

Fall 2008 Issue I, Volume I

Carolina Scientific

Fall 2008, Volume I Issue I 2

Staff WritersPrashant Angara Elizabeth BergenKelly Bleaking Natalia DavilaLenny Evans

Rebecca HolmesAlia KhanMary LaAnn Liu

Adrian PringleRebecca Searles

Guest WriterDavid McInnes

For more information, please email us at:

[email protected] or visit us online at:

http://studentorgs.unc.edu/uncsci

From the EditorsTo our readers: As undergraduates who have been involved in research since high school, we understand and recognize the importance of research as the source of new and exciting scientific knowledge. And who says that undergraduates cannot be involved in research? With UNC as one of the best public research institutions in the nation, we hope that this publication will help other undergraduate students learn about and become involved in the many research opportunities in labs across this campus. Enjoy! ~Ann, Adele, and Lenny

~Adele Ricciardi is a sophomore majoring in Biochemistry and

Biology.

~Lenny Evans is a sophomore majoring in Physics and Math.

~Ann Liu is a sophomore majoring in Biochemistry and

Business.

Mission Statement:Founded in Spring 2008, Carolina Scientific serves to educate undergraduates by focusing on the exciting innovations in science and current research that are taking place at UNC-CH.

Carolina Scientific strives to provide a way for students to discover and express their knowledge of new scientific advances, to encourage students to explore and report on the latest scientific research at UNC-CH, and hopes to educate and inform readers while promoting interest in science and research.

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Fall 2008, Volume I Issue I

ContentsReconstructing Factors Influencing Higher Incidence of Female ACL Injury Adrian Pringle4

Gamma Ray Bursts: Chasing the Biggest Explosions in the Universe Rebecca Holmes6

Nature’s Drawing Board: How Natural Products Aid in Drug Discovery & Synthesis Mary La8

Magnetoreception in Sea Turtle Navigation Rebecca Searles10

The Development of Synthetic Heparin Prashant Angara14

Autoimmunity: How Defense Mechanisms Can Hurt Our Bodies David McInnes16

Reproductive Biology & Behavioral Neuroecology: The Sockman Lab Elizabeth Bergen18

Yes to NO: UNC Researcher Explores Molecule for Biomedical Advances Natalia Davila20

Physics Tips for Living a Healthy and Happy Life at UNC Kelly Bleaking22

SURF: Cambodian Drinking Water Alia Khan24

Undergraduate Summer Research Spotlights Featuring Brittany Fotsch and Lalitha Kunduru26

Fantastic Neutrinos and Where to Find Them Lenny Evans12

Carolina Scientific


After he was tackled following a punt return, Brandon Tate

limped off the field. Bobby Frazor limped off the court after attempting to secure the basketball and landing awkwardly. The diagnosis for both athletes was a torn anterior cruciate ligament (ACL). During the past semester, about eight Lady Tarheel athletes suffered either a partial or complete ACL tear [1]. The major difference between male and female ACL injuries is that female ACL injuries often occur in the absence of physical contact. Herein lies the problem. Some coaches have taken precautions to insure the safety of their athletes [2]. These precautions range from modifying the strength and conditioning program to re-teaching the vintage jump-stop move to their players [1]. In general, ACL injuries are gruesome to witness. The performance of teammates can become severely diminished as they are constantly wondering if they will be injured next. The well-being of athletes and the skyrocketing costs of healthcare, serve as catalysts propelling research designed to reverse this trend [3]. Structurally, the knee is an unstable joint. This instability is mostly due to the fact that the femur does not fit well into the pocket created by the tibia. The knee joint is essentially held together by a

network of muscles and ligaments. David Bell, a doctoral candidate working in The Sports Research Laboratory at UNC, focused on the interaction between the hamstrings and the ACL. ACL rupture is due to excessive anterior tibial translation, movement of the tibia relative to the femur. The hamstrings are theorized

to protect the ACL by preventing this motion. ACL injury commonly results from direct trauma to the knee joint. Also, muscle imbalances within the hamstrings or quadriceps due to sport specific training regimens can culminate in ACL injury. Together or apart, these anomalies can result in excessive anterior tibial translation. When a ligament’s elastic properties are exceeded, the ligament can rupture. However, new research has indicated that female reproductive hormones may partially explain the increased incidence of injury to

females [2]. Male and female subjects were used in a study to determine whether reproductive hormonal changes negatively affect hamstring stiffness. Test subjects had no history of previous ACL injury and were physically active. Female subjects exhibited normal menstrual

cycles that were unaltered by contraceptives. Each female subject was tested three days after menses and again at ovulation. Menses marks the point of lowest concentration of estrogen in the female body, while ovulation marks the opposite [2]. By using these specific biological markers, researchers were able to create a range of low influence of estrogen to high influence of estrogen.

Across the twenty-eight to thirty days of a normal menstrual cycle, the concentrations of estrogen, progesterone, and luteinizing hormones fluctuate in the female bloodstream [2]. These hormonal changes, along with estrogen receptors on the female ACL, are one of the proposed reasons why females are more prone to ACL injury [1,6,8]. While the primary reproductive hormone of the male is testosterone, estrogen and progesterone are present in trace amounts. Intriguingly enough, the male ACL is immune to the

Structure of the Knee

Adrian Pringle, Staff Writer

Reconstructing Factors Influencing Higher Incidence of Female ACL Injury

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influence of estrogen because it lacks estrogen receptors [1]. Researchers found that estrogen levels and hamstring stiffness were negatively correlated. A negative correlation implies that increased blood concentration of estrogen results in decreased muscle stiffness [1]. Therefore, females have a less stiff muscle. A less stiff muscle could cause an entire joint to operate improperly [5]. Previous research has suggested that estrogen is responsible for decreasing the collagen content within connective tissue. Decreased collagen content could result in a less stiff muscle, forcing it to provide inadequate support to the joint [4]. The lack of proper joint support due to decreased muscle stiffness and collagen content may be reasons why females are more prone to non-contact ACL injuries. Contemporary female athletes are bigger, stronger, and more athletic than their peers from previous generations. This increased athleticism requires female athletes’ muscles to exert greater force on the bones to which they are attached. Rate of force production and time to 50% peak force data gathered by researchers might also be influenced by hormones. Rate of force production corresponds to how quickly a muscle can produce force, while time to 50% represents the split second timing to react and prevent injury. Estrogen and rate of force production yielded a negative correlation. However, no correlation existed between time to 50% peak force and estrogen. Instead, there is a negative correlation between time to 50% peak force and testosterone [1]. In the case of the knee joint, the quicker a supporting muscle can produce force, the quicker that muscle can correct

for joint misalignment and prevent injury [2]. Females have lower testosterone concentrations within their bloodstreams and it takes them longer to reach 50% peak force. Together, the negative correlation given for rate of force production and the negative correlation for time to 50% peak force, indicate possible explanations for the prevalence of non-contact ACL injuries suffered by female athletes [1]. Electrochemical delay (EMD) is the time interval between the initiation of electrical activity and force production during skeletal muscle contraction. Researchers found that there is no correlation between estrogen and EMD. A short EMD time corresponds to efficient interpretation of electrical activity by a given muscle. Theoretically, stiffer muscles have a shorter lag time between electrical signal and force production. Males generally have a shorter EMD time than females as a result. A longer lag time causes a muscle to react slower than required and may compromise joint stability [1]. Under these circumstances, female athletes would face an increased likelihood of injury. Researchers found correlations between concentration of estrogen and testosterone in relation to muscle stiffness, time to 50%, and rate of force production. These correlations suggest that estrogen could be responsible for rendering a muscle less stiff [1]. Hormonal fluctuations could prove detrimental by affecting the ability of the knee joint to respond to increased force placed upon it [5]. Thus, consensus can be drawn that the elevated estrogen levels of females could be responsible for creating conditions in which their knee joints are not as stable as those of their male peers

[7]. This induced instability could be one of the reasons why a female ACL injury often occurs in the absence of contact.

References1. Liu S.H. et al. (1996). Primary immunolocalization of estrogen and progesterone target cells in the human anterior cruciate ligament. J Orthop Res. 14, 526-533. 2. Bell, D. R. (2006). The Effect of Menstrual Cycle Phase on Hamstring Extensibility and Muscle Stiffness.3. Blackburn, J.T. (2004). Sex comparison of extensibility, passive, and active stiffness, of the knee flexors. Clinical Biomechanics. 19, 36-43.4. Agel, J., Bershadsky, B., Arendt E.A. (2006). Hormonal therapy: ACL and ankle injury. Med Sci Sports Exerc. 38, 7-12.5. Salmon, L. et al. (2006). Long-term outcomes of Endoscopic Anterior Cruciate Ligament Reconstruction With Patellar Tendon Autograft. Am J Sports Med. 34, 721-732.6. Wojitys, E.M. et al. (2002). The effect of the menstrual cycle on anterior cruciate ligament injuries in women as determined by hormone levels. Am J Sports Med. 30, 182-188.7. Interview with D. R. Bell, MEd, ATC, PES 11/04/20088. Fischer G.M., Swain, M.L. (1977). Effect of sex hormones on blood pressure and vascular connective tissue in castrated and noncastrated male rats. Am J Physiol. 232, 617-621.

~Adrian Pringle‘10 is an Exercise and Sports Science major.

Carolina Scientific


On the fourth floor of the Morehead Planetarium, UNC

physics professor Dr. Dan Reichart and his team are studying the early universe. Along with graduate students and professionals, UNC undergraduates Summers Brennan, Rebecca Holmes, Mark Schubel, and Jana Styblova use remote-control telescopes in Chile to observe gamma-ray bursts, the most powerful explosions in the universe. Gamma-rays are the most energetic form of electromagnetic radiation. They are far more energetic than visible light, the part of the electromagnetic spectrum the human eye can see. They are even more energetic than X-rays, which can pass right through human skin. Gamma-rays carry so much energy that they are only associated with violent phenomena like nuclear explosions. Gamma-ray bursts (or GRBs) were first discovered in the 1960s by satellites specifically designed to detect high-energy radiation—but not from deep space. The satellites were intended to monitor Soviet adherence to the Nuclear Test Ban Treaty. The United States suspected the Soviet Union might hide illegal nuclear weapons tests on the far side of the moon. The gamma-ray detectors on the satellites never saw evidence of such tests, but to the surprise of scientists, they did see bursts of

gamma-rays coming from deep space. The bursts were short, lasting at most a few minutes [1]. Two major explanations for the origin of these gamma-ray bursts emerged in the following decades. Both models involved the formation of a black hole with an “accretion disk” of material orbiting around it, but they differed on how that black hole was formed. One model suggested that the black hole was formed during the supernova explosion of a massive star. The other model suggested that the black hole formed during the collision and merger of two neutron stars. Neutron stars are extremely dense objects which are themselves the remnants of dead stars. More data were needed to determine which of these models was actually happening [2]. In 2002, Dr. Reichart discovered something interesting in the data for GRB 970228. There was an unexpected bright spot in the light that the GRB’s afterglow emitted [3]. This “bump” in the afterglow was consistent with the added brightness from a supernova explosion [2]. Its brightness and the time at which it occurred matched t h e o r e t i c a l

predictions about what a supernova associated with a gamma-ray burst should look like. Although there has since been some conflicting evidence, most astronomers now believe that at least one type of gamma-ray bursts come from black holes formed in the supernova deaths of massive stars. When a black hole forms from the death of a massive star, it is surrounded by a rapidly rotating accretion disk of material. As this material falls onto the black hole, it heats up, and the resulting energy causes some of the material still orbiting the black hole to shoot off in narrow jets traveling at nearly the speed of light. This ejected material moves through space, colliding with other material. “Like a snowplow that collects too much snow,” Dr. Reichart says, “it sweeps up gas and dust until it decelerates quickly, violently releasing most of its energy all at

Rebecca Holmes, Staff Writer

Artist’s depiction of a GRB, as formed by the collapse of a large star into a black hole

Gamma Ray Bursts: Chasing the Biggest Explosions in the Universe

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once in the form of a [gamma-ray burst]” [2]. Since gamma-ray bursts are so blindingly bright compared to other events in the universe, they can be detected on Earth even if they are extremely far away. GRBs are useful tools for studying the early universe because as astronomers look far off into the distance, they are also looking back in time. This is because light travels at a fixed and finite speed, so there is a time delay between when an event happens and when someone on Earth can observe it. For example, the sun in the sky on Earth is really an image of the sun as it was about eight minutes ago, because it takes about eight minutes for light to travel from the sun to the Earth. Looking at something much father away than the sun, like a gamma-ray burst, is looking much farther back in time. In fact, in 2005, then-UNC undergraduate Josh Haislip discovered a gamma-ray burst which was then the farthest known object in the universe—nearly 13.5 billion light-years from Earth[4]. Its light had been traveling for 13.5 billion years before it reached a telescope. Today, Dr. Reichart and his team

continue to observe and study GRBs using the PROMPT array of telescopes at Cerro Tololo near La Serena, Chile. PROMPT stands for Panchromatic Robotic Optical Monitoring and Polarimetry Telescopes. The array consists of six 0.41 meter Ritchey-Chretien telescopes which can be controlled remotely through the internet. Each telescope is optimized to observe GRBs in a particular wavelength, or color, of light. The telescopes can move rapidly across the sky, so when a GRB is detected by a satellite, PROMPT can automatically begin imaging the afterglow in multiple colors within seconds [5]. Students like Brennan, Holmes, Schubel, and Styblova then work to analyze the images from the telescopes and get information about the brightness of the GRB and how it faded over time. Once this initial data from PROMPT has been reduced—sometimes within hours—student researchers submit a report to the gamma-ray burst scientific community. Then the research continues, especially if the GRB seems unusual or interesting. Mathematical modeling with genetic algorithms can help refine scientists’ understanding of the mechanism behind GRBs. Data from images taken by PROMPT is fed into these models to improve them. Astronomers think they have pinned down a source of energy—the supernova explosion of a massive star—which could power gamma-ray bursts. However, the mechanism by which this energy becomes gamma-rays is still unknown. A complete model

of gamma-ray bursts will have to explain not only where these violent events get their energy, but also how the gamma-rays are produced. It will need to be able to predict the duration, brightness, color, and other characteristics of GRBs that Dr. Reichart and his students observe. Gamma-ray bursts which could be seen from Earth happen about once a day, each providing another opportunity to collect data and test predictions. For now, the mystery remains and the research continues.

Close-up of a PROMPT telescope

~Rebecca Holmes ‘11 is an Astrophysics major and a Creative Writing minor.

References:1. Schilling, Govert. Flash! The Hunt for the Biggest Explosions in the Universe. 1st ed. Cambridge, UK: Cambridge University Press, 2002.2. Reichart, Daniel. (2003) “The Gamma-ray Burst/Supernova Connection.” Mercury September/October 2003: 15-24. 3. P.A. Price, et al. (2003) “Discovery of GRB 020405 and its Late Red Bump.” ApJ. http://arXiv:astro-ph/0208008v3.4. J. Haislip, et al. (2006) “Discovery and identification of the very high redshift afterglow of GRB 050904.” Nature 440: 181-183.5. D. Reichart, et. al. (2005) “PROMPT: Panchromatic Robotic Optcal Monitoring and Polerimetry Telescopes.” Il Nuovo Cimento 28C: 767-770.

Carolina Scientific


Drawing BoardHow Natural Products Aid in Drug Discovery and Synthesis

Mary La, Staff Writer

Plants have been a source of natural medicines for as long

as they have been viable food sources. For example, willow tree extracts have been known to reduce inflammation and pain. More than seven millennia after its first recorded therapeutic use, one of its active compounds–salicylic acid–was chemically extracted, purified, and later fully synthesized. Though its painkilling effects were potent, salicylic acid was known to cause stomach ulcers. Near the end of the 19th century, Felix Hoffmann reduced its irritating effects by slightly modifying the compound to produce acetylsalicylic acid – more commonly known as aspirin [1]. This process exemplifies the importance of natural products in pharmaceuticals. “Natural product” is a general category that includes true, naturally occurring bioactive agents, as well as fully synthesized compounds with natural pharmacophores (bioactive regions) [2]. By linking natural products to chemical and

biomedical laboratories, medicinal chemistry has vastly expanded the number of drug candidates and expedited the development of safe and potent medications. Many drug discoveries from natural products originated from their therapeutic use in traditional or homeopathic medicine where some of the earliest examples came from the Chinese, Babylonians, Egyptians, and Greeks. Currently, due to advances in automation and chemical techniques, the screening of multiple natural products is the primary method of limiting the number of candidates to be tested for bioactivity and toxicity [3]. Novel drug lines may also stem from chemical modifications to the bioactive agent. In its original form, a natural product may be unstable, too toxic, too weak, or otherwise in a form that cannot be optimally used by the body. In this case, alterations must be made in order to produce an effective drug that can survive potential metabolism and extreme changes in biochemical environment before reaching its target. Scientists can reverse-engineer the functional agents found in natural products by imitating what the organism can accomplish with highly specialized enzymes and signal pathways. As with any process, this has both benefits and difficulties. Most natural products are not easily renewable and can be expensive to cultivate. An

efficient synthesis scheme for the target compound would make mass production of the bioactive agent manageable, but the structural complexity of most molecules of interest poses challenges in constructing multistep syntheses, stabilizing reaction intermediates, and recovering products efficiently. Recent successes in identifying and synthesizing pharmacophores have made combinatorial syntheses more popular. In a combinatorial synthesis, modular components (in this case, building block pharmacophores) are identified, and large libraries of structurally similar but chemically distinct candidate compounds can be generated from the combinations of these constituents. Advances in analytical chemistry and focused screening have permitted better efficiency in synthesis and identification of new bioactive compounds. Pharmacophores isolated from natural products have been modified and exchanged between parent drug structures in combinatorial schemes that generate “unnatural” compounds with new bioactivity. Still, there are several drawbacks to the application of combinatorial chemistry to bioactive compound synthesis. The constituents must be easily interchangeable, so more complex pharmacophores may have to undergo other levels of modification before participating in

Aspirin can trace its roots from the willow tree to the pharmacy counter.

Nature’s

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combinatorial synthesis. Peptides are often used in combinatorial schemes due to their relatively small size and commercial availability. Also, only select sites on a candidate molecule contribute to its bioactivity. Optimal conformations and arrangement of pharmacophores might already be determined by natural selection [4]. In reality, analyses of naturally derived agents involve a mixture of compound library screening, in vitro synthesis, and modification. At the Natural Products Research Laboratories of the UNC School of Pharmacy, the Lee group has used a combination of these three methods to produce derivatives of the flavonoid desmosdumotin B (DesB) with higher anticancer potency than the parent compound. Flavonoids are one of the classes of antioxidant c o m p o u n d s that give plants their color and have recently attracted interest as anticancer agents. Some tumor cells combat anticancer medication by increasing expression of genes that aid in multidrug resistance (MDR). Several of these genes, such as P-glycoprotein (Pgp) and MDR1, code for membrane proteins that actively transport bioactive compounds, including anticancer agents, out of the cell. Therefore, much emphasis has been placed upon finding compounds that regulate MDR gene expression, and flavonoids are particularly effective in tempering the activities of Pgp and MDR1.

In one study, sixteen DesB derivatives were produced via total synthesis, then screened against two cancer cell lines (nasopharynx carcinoma), one of which was resistant to the chemotherapy drug, vincristine. DesB and six select derivatives were additionally screened against cell lines from human lung, breast, colon, and prostate cancers. The activity of these derivatives was evaluated with ED50 (effective dose, 50%) values – the amount of the compound required to produce an effect (in this case, inhibit cell growth) in 50% of a test population. Ideally, minimal amounts of the compound could be used to produce significant results, so a lower ED50 is a mark of higher

bioactivity. Of the derivatives tested, it was found that modifications at a particular position in the DesB molecule (the 4’ carbon) resulted in

the lowest ED50 values for the vincristine-resistant nasopharynx cancer line, but not for the vincristine-susceptible line. In addition, the derivatives with napthyl B-ring substituents had relatively low ED50 values for all six cancer cell lines tested. As shown, analogs of a naturally derived compound may lead to a new series of powerful anti-cancer drug candidates [5]. The search for more effective bioactive compounds has become essential, especially in light of drug resistance exhibited by tumor cells and bacteria.

Naturally derived products, by offering drug candidates and potential pharmacophores to aid in total syntheses, have gained attention as the innovative source for structurally and functionally diverse compounds that could lead to the aspirins, morphines, and taxols of tomorrow’s pharmacopeia.

References1. Mahdi JG, Mahdi AJ, Mahdi AJ, Bowen ID (2006) The historical analysis of aspirin discovery, its relation to the willow tree and antiproliferative and anticancer potential. Cell Prolif. 39, 147-155.2. Newman DJ, Cragg GM, Snader KM (2003) Natural Products as Sources of New Drugs over the Period 1981 – 2002. J. Nat. Prod. 66, 1022-1037.3. Muñoz O, Montes M, Wilkomirsky T. Plantas medicinales de uso en Chile: Química y farmacología. Santiago: Edi-torial Universitaria, S.A., 1999.4. Ortholand JY, Ganesan A (2004) Nat-ural products and combinatorial chemis-try: back to the future. Current Opinion in Chemical Biology. 8, 271-280.5. Nakagawa-Goto K, Bastow KF, Chen TH, Morris-Natschke SL, Lee KH (2008) Antitumor Agents 260. New Desmosdumotin B Analogues with Improved In Vitro Anticancer Activity. J. Med. Chem. 51, 3297-3303.

~Mary La ‘11 is a

Chemistry and Spanish

double major.

Desmosdumotin B (DesB)

~With kind assistance and reviews from Dr. Michael Crimmins (Dept.

of Chemistry), Dr. Kuo-Hsiung Lee (School of Pharmacy), and Dr. Susan Morris-Natschke (School of

Pharmacy).

Carolina Scientific


Magnetoreception in Sea Turtle NavigationRebecca Searles, Staff Writer

It’s easy to see how an unprepared fisherman could find himself

lost at sea—misguiding currents, no land-markers in sight, and every mile passed looks exactly the same as the mile before it. Yet, below the surface, sea turtles are finding their way around just fine, even thousands of miles away from home. Researchers of the Lohmann Lab at UNC Chapel Hill are looking to find how these marine species and others engage complex sensory systems to navigate their open-sea migration routes.

Most sea turtle species migrate intermittently throughout their lifespan, traveling back and forth between feeding grounds, mating and nesting areas, and

seasonal habitats. But even more baffling to scientists is the species’ demonstration of natal homing. After 10-15 years of maturation, and thousands of kilometers traveled, they find their way back to the exact region they were born in to lay their eggs [1]. According to the research model, there are two components of information to marine animals’ ocean navigation: compass and map. Compass information is sometimes sufficient to orient an animal in the correct direction. For example, sea turtle hatchlings migrate from the nest to the safety of deep water, and need only to know that they are moving in a constant offshore direction rather than toward a specific destination. However, positional or ‘map’ information is needed to pin-point a specific goal or to guide the turtle along a complex migratory route. Using ‘map’ information, marine species can identify their location relative to a goal and ensure greater accuracy in reaching the destination [1]. So how do sea turtles acquire this map and compass information? Researchers have identified three significant types of directional and positional cues: geomagnetic, chemical, and hydrodynamic [1]. In recent years, however, researchers at Lohmann Lab have been focusing much of their attention on geomagnetic cues in

order to better understand the role of magnetoreception in marine species’ navigation systems. The concept of animals interpreting geomagnetic cues is based on the knowledge that they are able to sense the Earth’s magnetic field. This magnetic field is a constant environmental force that exists throughout all parts of the ocean, at all times of the day, and is unaffected by changes in weather and season. It is not surprising then, that animals have evolved a way to exploit this environmental feature as a guide that gives both directional and positional information. Directional, or compass information, is the simplest of these. Among the animals that have been found to possess it are isopods, spiny lobsters, sea turtles, and salmon. Determining positional information from the Earth’s magnetic cues is a little more complicated. There are several elements to the magnetic field that vary predictably across the surface of the Earth, which might enable animals to assess their geographic location. The first is the way the lines of the magnetic field intersect the Earth’s surface to form inclination angles. The field lines at the magnetic equator parallel the Earth’s surface, gradually becoming steeper as one nears either of the magnetic poles. Therefore, inclination angles

Dr. Kenneth J. Lohmann, Professor of Biology at UNC

Credit: www.unc.edu

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vary predictably with latitude, and animals that are capable of detecting these elements of the magnetic field would, in principle, be able to determine their position relative to a certain area [1]. Three other elements of the Earth’s magnetic field may act as navigational cues: 1) the horizontal field intensity, 2) the vertical field intensity, and 3) the total field intensity. Like inclination angles, these three elements also vary predictably across the Earth’s surface, lending themselves to navigation sense [2]. Lohmann Lab’s research has discovered that hatchling loggerhead sea turtles have the inherent ability to detect both magnetic inclination angle and field intensity. In one particular experiment, juvenile green turtles were captured from a feeding ground and placed in an arena where they were exposed to magnetic fields that existed 340 km north or south of the capture site. Turtles exposed to the field from the northern area swam south, whereas those that were exposed to the field from the southern area swam north. These results imply that the turtles utilized a magnetic map that would have led them back home had they been displaced to the locations where the two magnetic fields exist [1]. Animals with the ability to

derive positional information from the Earth’s magnetic field are said to possess a ‘magnetic map.’ It is important to note, however, that the term ‘map’ implies

the human notion of specific spatial representations, and it is unknown whether internal spatial representations exist in animals, or how closely they resemble the human concept of a map [2]. How ocean migrants manifest

this physiological ability remains a huge challenge to sensory biologists. Though scientists have discovered the physical basis for nearly all other senses, and even a mechanism for magnetoreception in bacteria, how animals perceive magnetic fields is still a great mystery. One of the main reasons the question is

so difficult to answer is because most nonhuman senses are extensions of human abilities, such as polarization detection and UV vision. Magnetoreception,

however, is not. Another complication is that biological tissue is essentially transparent to magnetic fields. This means that magnetoreceptors are not necessarily located on an animal’s surface and could potentially be anywhere in the body in order for them to function. This turns a two-dimensional inspection task into a three-dimensional one, requiring some very advanced imaging techniques. Yet another difficulty arises with the likely possibility that there is no central structure for the magnetoreceptors. Instead, they may be microscopic, intracellular structures scattered throughout the body, making detection nearly impossible [3].

A juvenile green turtle swims in an arena during a magnetic navigation

experiment

~Rebecca Searles ‘11 is a Biology major.

~Special thanks to Dr. Lohmann for his help and resources.

References1. Lohmann, K. J., Lohmann, C.M.F., Endres, C.S. (2008). The sensory ecol-ogy of ocean navigation. J. Exp. Biol. 211, 1719-1728.2. Lohmann, K.J., Lohmann, C.M.F., Putnam, N.F. (2007) Magnetic maps in animals: nature’s GPS. J. Exp. Biol. 210, 3697-3705.3. Lohmann, K. J., Johnsen, S. (2008). Magnetoreception in animals. Physics Today. 31, 29-35.

Figure 1: The four elements of a geomagnetic field vector, which could be another means

for providing animals with positional information.

Credit: D

r. Kenneth Lohm

ann

Fantastic Neutrinosand where to find them

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Neutrinos are elementary particles as fundamental as

electrons or the quarks that make up protons and neutrons. Unlike electrons and quarks, neutrinos are nearly massless and chargeless. This means that of the four fundamental forces of physics, neutrinos only interact via the weak nuclear force, which is not very powerful [1]. As a result, neutrinos rarely interact with matter, and in fact, over a trillion pass through you at any given second yet only a couple will interact with the atoms in your body in your lifetime [2]. This makes neutrinos difficult to detect, leaving many things unknown about them. The standard model of particle physics is a theory formulated in the 1970s that has required little change in four decades. It predicted that neutrinos were massless particles and that they differed from their antiparticles but there is now evidence that refutes this. The value of these masses is only weakly constrained - we only know that they are very light. It is also possible that the neutrino could be its own antiparticle, but the reactions in the experiments used to confirm or refute this claim have minimal half-lives on the order of ten trillion times the universe’s age [3,4].

Where Are They Found? The density of neutrinos in the universe is estimated to be around 300 per cubic centimeter, so they are basically everywhere [5]. These neutrinos are believed to be relics of the Big Bang and are the most abundant particles in the universe. Many elementary particles, such as the proton and electron, are charged, which made their discovery relatively easy. Not until later did the neutron, which has no charge, get discovered. Unlike the neutron, the neutrino does not have a quality known as “color,” so it cannot interact with nuclei through the strong nuclear force [1]. The neutrino could interact gravitationally, but on the nuclear scale, this force is 1034 times weaker than the weak nuclear force [6]. Thus, almost all neutrino interactions involve the weak force, which is responsible for beta decay. As a result, neutrinos can be produced in beta decay. Beta decay and many of its variants, such as double beta decay, electron capture, and

neutrino capture, have proved crucial to study the basic properties of neutrinos [4].

The Majorana Experiment UNC, along with 17 other institutions, is involved in an experiment known as Majorana that will try to determine whether the neutrino is its own antiparticle and possibly measure its mass [3,4]. An antiparticle has the opposite charge as a regular particle; when it interacts with its opposing regular particle, the masses of the two particles will be converted to energy according to Einstein’s famous relation E = mc2. If the neutrino were its own antiparticle, it would be called a Majorana particle [7]. Though this may sound like an unreasonable statement, other chargeless and colorless particles, such as the photon, are known to be their own antiparticles. Neutrino theorists have relied on the idea that the neutrino is its own antiparticle to formulate neutrino theories, but this fact has not been experimentally

confirmed [8]. Majorana, along with other experiments like EXO and CUORE, are trying to determine this property of the neutrino by searching for a hypothetical rare process known as neutrinoless double beta decay [9]. Double beta decay alone is a rare

Lenny Evans, Staff Writer

Schematic diagram of beta decay, in which a neutron is converted into a proton, electron, and an anti-neutrino.

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Fall 2008, Volume I Issue I13

process in which a nucleus like 76Ge undergoes two beta decays in rapid succession. The beta decays happen so quickly that due to the Heisenberg uncertainty principle, the first beta decay does not have to conserve energy, as long as the decay conserves energy as a whole. Theoretically, if the neutrino were its own antiparticle, the two neutrinos that should be given off by each decay could annihilate one another according to one possible mechanism, and give all its energy to the two electrons given off in the reaction [2]. However, this decay has an extremely long half-life, on the order of ten trillion times the universe’s age [9]. The Majorana experiment will use germanium detectors enriched in the double beta-decaying isotope 76Ge that will both be a source and detector of electrons from double beta decay. If the neutrinos take away no energy from the reaction, the electrons will take away all the energy of the reaction, and thus, if neutrinoless double beta decay can happen, we would expect to be able to detect two electrons with all the energy of the double beta decay. However, because the process is so rare, any noise in the detector could drown out the signal being sought in the experiment. This noise is mostly due to decaying

radioactive nuclei that occur naturally on Earth or are created by cosmic-rays [3,4,9]. One of the greatest goals of the UNC Majorana group is to find out how much this background noise will affect the experiment and find out how to minimize its interference. UNC is the lead institution on the

Majorana project; its team is led by project director, Dr. Wilkerson of the physics department. Dr. Henning, also of the physics department, was one of the leaders in the development of a computer program called MaGe that simulates the Majorana experiment. By using MaGe, researchers can alter various parameters, such as the amount of shielding placed around the detector, without having to spend money testing the various factors with actual experiments [10]. Others have been involved in testing the efficiency and spectrum output of germanium detectors that are similar to ones that will be used in the Majorana experiment. Groups at UNC are also involved with studying the ultra-pure materials required for the detector construction and different prototype detectors. Through all the preliminary efforts, Majorana hopes to have a working detector with as little noise as possible, in order to detect, to a high degree of certainty, two electrons taking away all the energy of a reaction in neutrinoless double beta decay. With these efforts, the Majorana team hope to achieve enough sensitivity to see this signal only once per year per tonne of

isotope[3,4]. Thus, it will take many years before some of the mysteries of the neutrino can be unveiled.

References:1. Mohapatra, Rabindra, and Palash Pal. Massive Neutrinos in Physics and Astrophysics. River Edge, NJ: World Scientific Publishing Co., 2004 (3-5).2. Esterline, James, and Mary Kidd. Double Beta Decay. Durham, NC: TILT Presentation, July 9, 2008.3. Wilkerson, John. The Majorana 0vbb Experiment. March 30, 2007. http://ma-jorana.npl.washington.edu/docs/TheMa-joranaExperiment.pdf4. The Majorana Collaboration. Neutri-noless Double Beta Decay and Direct Searches for Neutrino Mass arXiv:hep-ph/0412300v1.5. Bellerive, A. Review of Solar Neu-trino Experiments. International Journal of Modern Physics.6. Fundamental Interactions of Particle Physics Poster. cpepweb.org.7. Griffiths, David. Introduction to El-ementary Particles. Canada: John Wiley & Sons Inc., 1987 (20-24).8. Ronquest, Michael. Explanation of Neutrinoless Double Beta Decay. Dur-ham, NC: Lecture, June 19, 2008.9. Henning, Reyco. The Majorana Neu-trinoless Double-Beta Decay Experi-ment. Apr. 17 2005, http://majorana.pnl.gov/documents/HennningAPS05.pdf.10. Chan, Yuen-dat, et al. MaGe – a GEANT-4 Based Monte Carlo Frame-work for Low-Background Experiments. arXiv: hep-nucl-ex/0802-0860v1.

~ Lenny Evans ‘11 is a Physics and Math double major.

Proposed design of the Majorana detector, which has an array of Ge detectors

surrounded by a copper shielding.

Carolina Scientific


The anticoagulant heparin is one of the most widespread drugs today [1]. As a complex

carbohydrate that thins blood, heparin has the ability to stop blood from clotting, making it incredibly useful in medicine. Often used to treat bleeding disorders, it is also used in heart surgery and the artificial kidney, among many other uses. This versatility creates an enormous demand for the drug, about 30-

40 tons per year, worldwide. The current method for meeting this demand is by isolating it from pigs, using somewhere between 400-700 million pigs [2]. However, the risk of impurities within the heparin samples is high, due to the anticoagulant’s lengthy isolation and purification process, and the lack of quality control and standardization of the pigs from which the heparin is derived. All of this led to the March 2008 heparin contamination, killing 81 people in the United States alone [1]. The raw heparin product was produced in China and imported to the United States [3]. However, this heparin was different in that it had been intentionally

contaminated with an inexpensive mimic of real heparin. The counterfeit heparin was able to pass routine testing, and was thus imported and used in the United States [3]. Heparin is a large carbohydrate that can be easily broken down into a disaccharide molecule that repeats 200-400 times. Scanning for impurities is often difficult because of the sheer size of the molecule. Any of the disaccharide units can be replaced, as they were in the counterfeit, without significant changes in the chemical’s physical or chemical properties [2]. The fake heparin shipped into the United States had up to 20% of the active ingredient replaced by chondroitin sulfate [4]. This over-sulfated version of heparin was only found after detailed scanning [3]. How do we avoid such problems and contaminations in the future? The solution: synthetic heparin [2]. Synthetic heparin, as the name implies, is a man-made version of heparin that has its advantages over its animal-derived counterpart. Firstly, the production method for synthetic heparin is much simpler, and secondly, synthetic heparin could be more effective. Synthetic heparin is composed of only heparin that contains the active ingredient, whereas the bioactive molecule constitutes a mere one-third of natural heparin. Therefore, a synthetic version would be more potent and, hopefully, have fewer side-effects on humans. One of the biggest side effects of heparin is heparin-induced thrombocytopenia. This occurs in about 4-7% of patients treated with heparin and causes platelet clots to form. These clots are similar to blood clots but are due to platelets rather than red blood cells [2]. Dr. Jian Liu of the University of North Carolina at Chapel Hill School of Pharmacy has come up with a method of creating this synthetic heparin. The technique uses bacteria, one chemical reaction, and two enzymatic steps to create a small amount of the desired synthetic variant. He harvests a disaccharide (figure 1) from the bacteria E. Coli and exposes it

Prashant Angara, Staff Writer

The Development of Synthetic Heparin

Structure of Heparin Disaccharide Unit

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to two enzymatic processes to create the desired disaccharide [2]. When many of these disaccharides are combined, the synthetic heparin is formed. Dr. Liu adds sulfate groups (SO3) to the NHCOCH3 and two of the -OH groups on the disaccharide. Sulfating the NHCOCH3 can be done via a chemical reaction because differentiating nitrogen from the -OH group is simple. However, differentiating the various -OH groups from each other is chemically difficult and must be done via enzymatic reactions. Because enzymes are very specific, it is possible to sulfate the correct -OH group [2]. Figures 2, 3 and 4 show the process used to create the synthetic heparin.

This method of production only produces about 1 milligram of heparin, nowhere near the required amount [2]. Dr. Liu’s next goal is to try to create more synthetic heparin. He hopes to first synthesize between 1-10 grams, and then move to the kilogram level required for global production. He likes to think this is possible, but different equipment and synthesis optimization will be required. Research labs can only produce small quantities and are not designed for mass production. Currently, Dr. Liu is negotiating with various financial backers to obtain better equipment. He also hopes to make the market price of his heparin competitive with current heparin prices. The current price for animal derived, semi-pure heparin is about $4,000-$5,000 per kilogram and Dr. Liu hopes to get the price of his synthetic heparin close to this value. Even if his heparin is slightly more expensive, he rationalizes that the safety and purity of the product will allow it to compete with the heparin currently on the market [2]. With these goals in mind, he returns to the lab.

References:1. Harris, Gardiner. April 22, 2008. “U.S. Identifies Tainted Heparin in 11 Countries”, New York Times.2. Interview with Jian Liu, Ph.D 2008, 9/22/20083. Bogdanich, Walt. March 6, 2008. “Drug Tied to China Had Contaminant, F.D.A. Says”, New York Times. 4. Bogdanich, Walt. March 20, 2008. “Heparin Find May Point to Chinese Counterfeiting”, The New York Times.

Figure 1: The original disaccharide unit harvested from E. coli

Figure 2: NHCOCH3 is changed to NH2SO3

via a chemical reaction involving NaOH and

SO3-.

Figure 3: The CH2OH is

sulfated into a CH2OSO3

-.

Figure 4: Another CH2OH is sulfated into a CH2OSO3 to

create final synthetic heparin disaccharide.

~Prashant Angara ‘12 is a Chemistry major.

~Special thanks to Dr. Liu for his time and help.

Carolina Scientific


Comedian Jerry Seinfeld quipped that a dermatologist’s

entire profession “revolves around saying ‘Put some Aloe on it.’” But dermatologists here at the University of North Carolina School of Medicine are knee-deep in research on a handful of insidious diseases of which most Americans have never heard: the autoimmune bullous diseases of the skin. The research laboratories here in the Department of Dermatology, where I have worked for the past three years, is one of the few research centers in the world focused on these diseases. This emphasis on research, along with excellent patient care, has been a trait of the Department for many decades, and can be attributed to the late Dr. Clayton E. Wheeler and to Dr. Robert A. Briggaman. Dr. Wheeler had been a dermatologist at UNC since 1951 and became the first chairman of the Department in 1972. Even after stepping down in 1987, when Dr. Briggaman

became chairman (until 1999), Dr. Wheeler continued to see patients until shortly before his death, in 2007. Dr. Luis A. Diaz began his tenure as chairman in January, 2000. Dr. Diaz, Dr. Briggaman, and others speak admiringly of Dr. Wheeler as a great mentor and the driving force behind the current research efforts into the autoimmune bullous diseases. Autoimmunity is the improper misuse of our defense systems in attacking ourselves. Essentially, immune cells mistakenly recognize elements of self as foreign invaders, and autoimmunity is medically defined as an immune response to self or autologous antigens. The diseases can be organ-specific, such as those of the skin or thyroid, or non-specific, as in the case of lupus [1]. Autoimmune bullous diseases consist of antibodies, primarily IgG class, which are produced by white blood cells known as B cells. These antibodies act on the proteins that hold the epidermal cells to each other in the epidermis and to the dermis below. This causes acantholysis, or cell separation, and the formation of subepidermal bullae, or large blisters. The lion’s share of research performed by the UNC Department of Dermatology is on diseases that fall into two primary groups: the Pemphigus diseases, primarily pemphigus foliaceus (PF) and pemphigus vulgaris (PV), and the Pemphigoid

diseases, mainly bullous pemphigoid (BP). Researchers at UNC-Dermatology, such as Dr. Diaz, Dr. David S. Rubenstein, and Dr. Zhi Liu, approach these diseases from several different angles [1]. Dr. Luis A. Diaz has been doing extensive research on PF for decades. PF autoantibodies target desmoglein 1 (Dsg1), a strongly adhesive cell surface protein which holds cells of the granular layer together, close to the surface of the skin. Ongoing work between Dr. Diaz and other immunologists is aimed at determining why B cells produce autoantibodies in the first place. While somewhat rare in the United States, PF is significantly more common in South America, particularly Brazil. Among Amerindian populations on reservations in Brazil, there are several clusters of the disease in certain regions. There, the endemic PF found in these clusters is known as Fogo selvagem (FS), or “wild fire,” a Portuguese name given to the disease centuries ago by local inhabitants [2]. Dr. Diaz travels to Brazil every year to study and treat individuals at the Limao Verde Indian reservation, which has one of the highest prevalences of FS in the world, around 3%. While treating individuals there, he requests blood samples with which to perform FS research back at UNC. Dr. Diaz is convinced that there is a genetic

Artist’s depiction of IgGAbove, B cells

David McInnes, Guest Writer

Autoimmunity:How Defense Mechanisms Can Hurt Our Bodies

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component to the disease, as well as a possible environmental factor, such as the hematophagous biting insects, which seem to trigger the disease. Dr. Diaz has compiled genealogies of the resident families and has been tracking the disease for decades in those families. His number one wish is to identify the cause of, and the cure for, PF/FS before he retires [2]. Dr. David S. Rubenstein is concentrating on PV, where patients produce autoantibodies against Dsg3, a binding protein found in the deeper superbasal cells. In order to prevent acantholysis, Dr. Rubenstein studies the downstream effects on the proteins that are bound and the effects of that binding on skin cells. His work focuses on dealing with those effects and on preventing skin damage, even after binding occurs. Some positive results of his research are already being examined for practical applications of the pharmacological control of the disease [3]. Dr. Rubenstein has been working at UNC since he started his residency here in 1994. As attending physicians, he and Dr. Diaz regularly see patients at the Department’s two clinics, one here on campus in the Ambulatory Care Center and the other in the Southern Village community of Chapel Hill [3]. Dr. Zhi Liu’s research focuses on the pathogenesis of BP, and he is determined to learn as much as possible about new therapies to control the disease. BP targets the proteins that hold the epidermal basal cells to the dermis, along what is known as the Basement Membrane Zone (BMZ). The

BMZ of the skin consists of a wide variety of collagens and other matrix proteins. BP produces autoantibodies against BP180, an epidermal basal binding protein, and causes deep and painful blistering. Research in Dr. Liu’s lab has progressed to the point that recently it has been shown that the epitope, or the precise antibody-binding region, of the BP180 antigen is a very small stretch of the protein known as NC16A. This protein and its gene have been sequenced, leading to the creation of “humanized” mice, which express human NC16A on their BMZ. Using these “humanized” mice, research on the effects of BP autoantibodies is proceeding very quickly, leading to important findings in the pathogenesis of this disease [4]. To a lesser degree, Dr. Liu researches other autoimmune diseases involving the BMZ proteins, such as Linear IgA Bullous Dermatosis, and Epidermolysis Bullosa Acquisita. The clinical laboratory, where I work with Dr. Diaz, is easily able to diagnose these cases from blood samples and biopsies, obtained by clinicians from UNC and other state dermatologists [4]. For those not in the field, it can be difficult to understand the lengths to which research in a particular field must go. While millions of patients around the world suffer from various kinds of autoimmune diseases, Dermatology is often perceived as a lesser field. Considering the embarrassment, the discomfort, and even the risk of death, for

those with any of these diseases, this perception couldn’t be more untrue.

Autoimmune bullous diseases cause severe blistering of the epidermis

References1. Culton, D. A. et al. “Advances in Pemphigus and Its Endemic Pemphigus foliaceus (Fogo Selvagem) Phenotype: A Paradigm of Human Autoimmunity.” Journal of Autoimmunity. 30 (2008): 1-14.2. Diaz, Luis A., MD. Personal Interviews. 8 Sept 2008. 10 Oct 2008. 30 Oct 2008.3. Rubenstein, David S., MD, PhD. Personal Interviews. 29 Oct 2008. 3 Nov 2008.4. Liu, Zhi, PhD. Personal Interviews. 26 Sept 2008. 17 Oct 2008. 24 Oct 2008.

~David McInnes is a part time graduate student and a full time research assistant in the UNC

dermatology department

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Reproductive Biology and Behavioral Neurecology: The Sockman Lab

Elizabeth Bergen, Staff Writer

Each summer, Keith Sockman and a crew of

both undergraduate and graduate students travel to a wet meadow in the Colorado Rockies. They’re looking for one little brown bird: the Lincoln’s sparrow, Melospiza lincolnii, which migrates to high-altitude meadows for the summer breeding season. The Sockman crew spends two months in the field collecting data on the sparrows’ reproductive biology, which later provides ecological context to controlled experiments done in the lab. In the Sockman Lab, under-graduates wishing to conduct original research in ecology have a wide range of opportunities. Dr. Sockman eagerly encourages students to develop research projects in the field or in the lab on whatever topic most interests them. One student might use genetic techniques to determine nestling gender distributions. Others might examine hormone distribution in the avian brain or study the relationship between song quality and mating success.

Frequently, research topics are derived from direct observations of the birds in their natural environment each summer.

A Summer in the Field Field research at 10,000 feet is a grueling, but rewarding, experience. Members of the field crew typically wake up before sunrise to record birdsong and then spend the rest of the day

searching for nests, trapping and banding adult sparrows, or feeding hatchlings that have been collected from the field, among other tasks. Crew members work eight hours a day and seven days a week. The ability to cope with living in very small groups is crucial to semi-remote field research. For up to two and a half months the field crew lives in a single campsite with limited internet and cell phone access and only periodic trips into the nearby small town of Silverton, CO. Frequent bad weather, biting insects, and hard physical work compound social stress among members of the crew. For those who can maintain good spirits in adverse conditions, working on the Sockman field crew provides a precious opportunity. Not only can undergraduates obtain serious research experience, but Dr. Sockman puts forth extra effort to engage his crew members in the scientific process above and beyond the project at hand. Evenings in camp are spent reading scientific papers for journal club.

Above: Lincoln’s sparrow; Top: the Molas Pass field site

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Dr. Sockman enthusiastically challenges his crew to keep all their senses open and to stay alert for mysteries in the natural world that could inspire future research projects. Undergraduates interested in joining Dr. Sockman’s summer crew are encouraged to review his recent publications on his website, www.unc.edu/~sockman.

Funding Sources and the Undergraduate Research Symposium A variety of funding sources may be applied to research conducted in the Sockman lab. Students who work in the lab during the school year may apply for Undergraduate Research Support Grants of up to $750. Eligible seniors who wish to do an honors senior thesis, which requires enrollment in Biol 395/396 and Biol 691H/692H, may apply for an Honors Thesis Research Grant of up to $1000. First-year or sophomore students may apply for the Science and Math Achievement and Resourcefulness Track (SMART) program, which awards $2000 for a semester of research.

The Sockman lab pays members of its field research crew a living stipend of approximately $100 a week. Students may also apply for a Summer Undergraduate Research Fellowship (SURF) for up to $3000. The SMART program also provides a $3000 summer fellowship. Students who choose to take advantage of these funding sources are invited to present a poster of their work at the annual Undergraduate Research

Symposium, which takes place in the spring.

A Lincoln’s sparrow hatchling in the author’s hand

How to Get InvolvedInterested in doing research in the Sockman Lab? Send an email to Keith Sockman at [email protected] and include: 1) a resume or C.V. 2) a brief explanation about why you are interested in joining the lab

For more information, visit:www.unc.edu/~sockman

~Elizabeth Bergen ‘10 is a Biology major. Last summer she traveled to Molas Pass with the SURF fellowship to study the relationship between arthropod food availability and nest timing. She currently is completing her project in the Sockman lab.

Avian brain sections in

the Sockman Lab that will be optically imaged to determine hormone

distributions

Carolina Scientific


How does an undergrad at the University of Kansas

go from a major in German and a mild interest in Chemistry classes to becoming a professor and researcher of biomaterials, sensors and new therapeutics at the University of North Carolina at Chapel Hill? Internationally recognized research scientist Dr. Mark Schoenfisch was, like many undergraduates, undecided about his career path and even his major until a friend suggested talking to a professor about joining a research lab. His curiosity broadened working in the lab because, as Dr. Schoenfisch puts it, he could see the applications of chemistry and the connections between different branches of science more easily than simply doing chemistry homework.

The enthused graduate went on to earn his Ph.D. in Chemistry at the University of Arizona where he worked with p a c e m a k e r e l e c t r o d e s and explored their surface chemistry. At Arizona and during his p o s t d o c t o r a l years at the University of Michigan, the c o n n e c t i o n b e t w e e n chemistry and b i o m e d i c a l e n g i n e e r i n g developed in his research, which he later brought to UNC. In 2000, the Schoenfisch lab officially began with projects spanning analytical chemistry, organic chemistry, polymer chemistry, microbiology and biomedical engineering. Over the years, the group’s interest has expanded to include on investigating protein adsorption and designing nitric oxide (NO) releasing materials [1]. The latter covers a wide array of projects and new techniques being used by the Schoenfisch group. Testing NO’s roles in human physiology is a relatively new area in chemistry. Typically

recognized as a toxic air pollutant, the versatile gas acts as a natural

anticoagulant, a neurotransmitter and an a n t i b a c t e r i a l agent in the immune system [2]. Nitric oxide kills bacteria and thus may be useful for designing more biocompatible sensors and implants. A s i g n i f i c a n t l i m i t a t i o n in the use of s u b c u t a n e o u s in vivo sensors (used

for monitoring physiological status of patients) and implants, such as catheters and artificial prosthetics, is their inadequate biocompatibility [3]. Days, even hours, after implantation, the human body responds to these devices as foreign objects, which triggers platelet and protein adhesion, biofilm formation and encapsulation of the device [1]. These biological responses not only compromise the performance of the sensors and implants, but also cause infection and pose other health risks [4]. Dr. Schoenfisch’s group, consisting of postdoctoral fellows and graduate and undergraduate

Credit: http://www.chem.unc.edu/people/faculty/schoenfisch/group/index.html

Lewis Diagram and 3-D Model of Nitric Oxide

Yes to NO:UNC Researcher

EXPLORES Molecule for Biomedical Advances

Natalia Davila, Staff Writer

Dr. Mark Schoenfisch, Assistant Professor of Chemistry

Credit: M

ark Schoenfisch

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students, is tackling the challenge of improving the biocompatibility of these sensors by developing polymer membranes that make use of active release strategies. Among the many focuses of the lab, they are investigating NO release coatings via diazeniumdiolate NO donors that function as natural NO releasing agents. Nitric oxide has proven to inhibit platelet adhesion, suppress bacterial growth, promote wound healing and kill parasites when exposed in the human body [2]. Schoenfisch group studies have also revealed that the slow release of NO from a polymer membrane, for instance on in vivo sensor surfaces, reduces biofilm formation and bacterial adhesion [4]. Though the beneficial characteristics of NO seem favorable, a few problems persist when using this gas: the uncontainable and disorderly characteristics in the body and the possibly toxic effects [5].

NO oxidizes quickly and is very reactive. Therefore, NO storage has been one of the biggest challenges. The Schoenfisch team constantly works to develop new materials that store more and more quantities of the molecule and effectively control the release of NO [5]. The latter is a particular challenge as well because exposure to NO in high quantities can be toxic [2]. Although they usually fit under the umbrella of analytical chemistry, Dr. Schoenfisch runs projects and a laboratory that involve a variety of scientific disciplines including analytical, polymer and organic chemistry, physics, and biomedical engineering. A man who simply calls himself a chemist, Dr. Schoenfisch professes that collaboration is a key component of his research and multidisciplinary laboratories are important for solving medicine’s most significant problems [1].

References:1. Interview with Mark H. Schoenfisch, Ph.D. 2. L.K. Keefer, CHEMTECH, 1998, 28(8), 30-35.3. J.H. Shin and M.H. Schoenfisch, The Analyst, RSC, 2006, 131, 609-615.4. E.M. Hetrick and M.H. Schoenfisch, Chemical Society Reviews, 2006, 35, 780-789.5. D. Jacobs, Endeavors, Carolina Alumni Review, 2007, 24, 7-9.

~Natalia Davila ‘11 is a Studio Art and Chemistry double major.

~Special acknowledgement to Dr. Schoenfisch for devoting his time and resources.

Figure 1. A) Subcutaneous electrochemical glucose sensor plagued by bacteria biofilms and poor wound healing (e.g., fibrous encapsulation). B) Nitric oxide-releasing sensor that eliminates biofilm and reduces capsule thickness

thereby enhancing the analytical response properties of the device.

Credit: Mark Schoenfisch

A) B)

Carolina Scientific


Ask someone what they think about physics and you will hear “physics is difficult and boring!” But there are so many cool components to physics about which most people don’t know. For instance: do you

know how to have extra time to study for your tests? How to travel through time? How to avoid being eaten by black holes? The following are some tips for navigating the nuances of physics for successful adventures here at UNC.

According to Einstein’s Theory of Relativity, time is different at different heights: a clock farther from the surface of the earth will tick

faster. So you should study on the eighth floor of Davis Library because you will have more time to study compared to those unknowing students on the first floor. (Caution: the time it takes you both to wait for, and ride up in, the terrifying elevators - built before most of us were born - will negate the time you save; but who’s counting?).

You’re in class one day and you’re waiting anxiously for your test results from a ridiculously

hard test. The class average was a 43, so you think that, this time, the professor will have to curve. (After all, there’s no way anyone got above a 70, right?) You glance over at the guy sitting next to you, and for the third time in a row, he’s received a perfect score! Looks like there’s no curve for you, again. But it’s okay: he’s from the future and simply not telling. Relax. All you have to do is be his friend, and next time, he will take you back in time with him. Currently it is believed that time travel forward in time is possible and time travel backwards is not;

moving very fast, traveling forward in time is possible, as you would have a different relative time compared to Earth time (after several years of traveling very fast in space, a twin who went into space would be younger than his twin who stayed on earth). While traveling back in space is not currently considered

TIP #1: How to Find Extra Time... in Davis Library!

Davis Library

TIP #2: Time Traveling to Beat the Curve!

Physics Tips for Living a

Healthy and Happy Life at UNC

Kelly Bleaking, Staff Writer

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possible; however, the theory is that wormholes, or shortcuts, between two points in space, exist. If people could travel through this wormhole, they could travel backwards in time. But the gravity of a wormhole would cause it to collapse almost immediately after forming. It could be possible in the future to produce some kind of antigravity device that could keep the wormhole open long enough to travel through it (check with the guy with the perfect scores!).

Your new friend agrees to take you on a time travel expedition. He’s just glad you don’t hate him (like everyone else does). So you go in his spaceship and he says “all you have to do to improve that test

grade is ride this blue probe through the black hole in the distance.” You’re still not so sure about this guy (after all, if he’s from the future, and has an awesome spaceship, why does he waste time in class instead of on saving the world?) And he does have a suspicious look in his eye and he really wants you to go into the black hole. You vaguely remember something about black holes, but what was it? Thankfully, as a physics student, you would remember that if you were on a spaceship 15,000 km from a black hole five times the mass of the sun, and you sent a probe that emits a blue glow towards the black hole, from your point of view, the probe would take an infinite amount of time to reach the surface of the black hole. However, you wouldn’t be able to see it with the human eye. As the probe falls, the gravity of the black hole causes the light of the probe to have longer and longer wavelengths. This means that the light from the probe will turn from blue to green to yellow to red and will eventually have a wavelength that you cannot see. If you had infrared goggles, near the surface of the black hole, the gravity would be so much stronger on the part of the probe closest to the black hole than on the part farther away, that it would stretch the probes out like spaghetti, rip it into atoms, and then even rip the atoms apart. To the probe, or someone with the probe, there would be no change of time or color. He would simply get close to the black hole and be ripped apart. So if your buddy is trying to convince you that you should be the one to enter the black hole to figure out what’s inside, and he tells you he’ll watch and see what happens, don’t do it! The upside is that now you know better and aren’t going to be ripped into atoms, but the downside is you’re trapped in a spaceship with someone who just tried to kill you (no wonder everybody hates him). Perhaps instead of time travel and black hole expeditioneering you should take your chances on the 8th floor of Davis. Good luck!

TIP #3: Gosh-darned Black Holes!

An artist’s depiction of a black hole, Credit: NASA

~Kelly Bleaking ‘11 is currently undecided in her major.

So if you think you’ve seen the light and discovered how phun

physics can be, you should join UNC’s Society of Physics

Students! To find out more information, contact Jon Toledo at [email protected] or

join the listserv: [email protected].

Carolina Scientific


SURF: Cambodian Drinking Water

As I stared out the window of the plane while flying into Cambodia, I could see two of the

major rivers of this region- the Mekong and the Tonle Sap. The further we descended, the clearer I could see the land below me, and the more I realized how very different the landscape, climate, and culture would be from the Old North State I had recently left. As the plane touched down I knew I was in for an amazing adventure over the next two months and was filled with motivation to dive headfirst into my field research while assimilating into the Cambodian way of life. Through a Summer Undergraduate Research Fellowship (SURF), I had the opportunity to travel to Kean Svay, Cambodia to conduct environmental microbiology field research in the summer of 2007. Effective water treatment has been the most important factor influencing advances in public health in the last century [1]. However, 1.1 billion people still lack access to improved drinking water and as a result suffer from water-borne diseases such as dysentery and diarrhea. In developing countries such as Cambodia, surface water is polluted with pathogens and ground water is contaminated with heavy metals such as arsenic. Water disinfection supplies are often inaccessible for typical Cambodian families living on less than $2 US a day, and the amount of disinfectant needed in areas with highly polluted water can often be too toxic or unpalatable to consume on a regular basis. In order to identify which waters are contaminated, there must be procedures to assess

water quality, as well as to evaluate the effectiveness of the microbial and chemical methods used to treat water [1]. The aim of my studies was to compare the efficacy of four alternative low cost/simple methods to detect E.coli with the standard US-EPA method, membrane filtration. If the results proved similar, the need for expensive methods could be deemed unnecessary, therefore making identification methods more accessible to developing communities.

The base for my research was my generous host, Resource Development International- Cambodia (RDI-C). RDI-C is a local non-governmental organization (NGO) based in a village in Kean Svay, about 30 minutes outside of Phnom Penh by car.

Cambodia, a country in Southeast Asia

Credit: Alia KhanOpen well in Kean Svay, one of the three types of

water sources tested.

Alia Khan, Staff Writer

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This NGO has on-going tangible community-based projects, ranging from clean water and sanitation to sustainable agriculture and head-lice soap production. During my stay I had the opportunity to accompany a work-crew to complete a rainwater catchment tank in Preak Russai- a remote Cambodian village with drinking water 200 times the World Health Organization safe-level of arsenic. Field work was one of the most rewarding aspects of my trip, as well as the relationships that I formed with the NGO staff and local villagers. Throughout my study, I had the benefit of collecting my own water samples from common drinking water sources from village homes throughout Preak Thom (the village RDI was based in), as well as surrounding areas- usually travelling by ‘moto’ (motorcycle). While there are obviously many cultural differences between the U.S. and Cambodia, as a science student, one aspect that greatly intrigued me is how these differences translated into the lab atmosphere. In most western laboratories, it is required by law to wear closed toed shoes. This was never a problem in Kean Svay, as it would have been culturally improper not to remove my shoes before entering the lab. By the end of two months of research, I found evidential support for the effectiveness of the alternative methods tested. These methods could be used to replace the more expensive standard E.coli

membrane filter method, and hence provide cheaper and more accessible methods to identify c o n t a m i n a t e d drinking water for developing countries such as Cambodia. The o n - t h e - g r o u n d perspective that I gained to water and sanitation issues facing rural Cambodia was an invaluable e x p e r i e n c e , and I learned a tremendous amount from my advisor,

Dr. Mark Sobsey, my host organization RDI-C, and its director, Dr. Mickey Sampson. Having the opportunity to work side by side with Cambodian staff, as well as conduct my own research miles away from my sponsoring advisor, gave me the opportunity to grow as an independent academic researcher while also enriching my appreciation for the variety of atmospheres in which similar research can be conducted.

References1. Madigan, Michael T, Martinko, John M., Parker, Jack. Brock Biology of Microorganisms. 10th ed. Upper Saddle River, NJ 07458, Pearson Education, Inc, 2003.

The RDI-C Microbiology Lab *Note the shoes by the doorCredit: Alia Khan

~Alia Khan ‘09 is an Environmental Science and Engineering major.

Carolina Scientific


Undergraduate Summer Research Spotlights

1. How did you hear about your program? Last fall, I was invited to an event on Facebook. The event was an information session about Summer Undergraduate Research Fellowships. After the information session, I went to the Office of Undergraduate Research to find out all I could about their fellowships. I applied for a SURF and also found out about the Science and Mathematics Achievement and Resourcefulness Track Program (SMART). I decided to apply for this program as well, and this is the one I chose to participate in last summer.

2. Describe the application process. Any tips/suggestions? The application process is pretty simple for the SMART program. You must fill out an application online describing your general information, the various science and mathematics courses you have taken in college and high school, and why you would be competitive for the program. The last part is an essay. I suggest spending a good amount of time on the essay and definitely having a professor proof read it for you. After your application has been reviewed by Dr. Parikh and Dean Woodard, you may be asked to come in for an interview. This is the

most important part of the application process. If Dr. Parikh and Dean Woodard feel that you would be a nice addition to the program, then you’re in! I would suggest dressing in business attire for the interview. It’s always better to be overdressed than underdressed, and in business attire, you will seem more impressive. Be yourself in the interview. Don’t get nervous. If the program is meant for you, then you have nothing to worry about.

3. How did you find a lab to work for and what was your research about? I found a lab before I came to UNC, and began working in that lab just before my first semester of college. I was able to do this through my professor of medicinal chemistry in high school. I would recommend others to search their majors’ websites for professors willing to accept undergraduate students into their lab. Although, if you are interested in the SMART program, they will match you with a professor if you don’t already have a lab to work in. My research was about the RyR1 ion channel, which controls muscle contraction. I worked on trying to find a model through computer simulations to imitate how it works.

4. Overall, how was your research experience? What were some positive aspects? Negative aspects? Random fun facts? My research experience was amazing. It’s the best way to spend a summer. I was paid for something I love to do anyways. I got to know people in my lab so well. Everyone becomes sort of a family in a lab. The people in my lab now even help me with some of my classes if I have questions. I learned so much this summer, including computer programming, how to use Matlab and Mathematica, all about ion channels, and so much more. It was an amazing learning experience. I would say that it was a little annoying to have to compile PowerPoint presentations of my weekly progress, but in the end, it was completely worth it. I am so much more comfortable speaking about my work in front of an audience now, and at the end, we, the SMART fellows, were able to present our work to many others including our families. Also, the SMART program introduced me to the Alliances for Graduate Education and the Professoriate (AGEP) program. I am now an AGEP fellow, which is also an amazing experience. To find out more about the AGEP program, go to http://www.unc.edu/agep/. To find out more about the SMART program, go to http://www.unc.edu/depts/our/students/fellowship_supp/smart.html. To find out more about the SURF program, go to http://www.unc.edu/depts/our/students/fellowship_supp/surf.html.

~Brittany Fotsch ‘11 is a Chemistry major and currently works in the Dokholyan Lab at UNC.

Compiled by Ann Liu, Staff Writer

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1. How did you hear about your fellowship/program? Found out about the Baylor SMART program at Rice University from Google

2. Describe the application process. Any tips/suggestions? The application consists of a general information sheet, transcript, listing career goals, 2 letters of recommendation, a page about prior research and training experience, a skills assessment/evaluation sheet about what you know/can do. (Prior research expe-rience is not absolutely necessary.) About 95% of the participants were rising juniors/seniors. They give preference to students who have in interest in graduate school/medi-cal school.

3. How did you find a lab to work for and what was your research about? I was matched with a lab based on my interests. (You list 3 areas of interest in your application.) If you have a specific request to work in a particular lab, you can also list it on your application. My research was nutrition-related and about iron bioavailability from Arabidopsis thaliana leaves.

4. Overall, how was your research experience? What were some positive as-pects? Negative aspects? Random fun facts? It was great! Positive aspects include a seminar series (everyday from 12-1) when we had a speaker come and talk about their research, evening activities, career development sessions, as well as social activities. The people I met there came from very diverse backgrounds—students from all over the nation, several from Puerto Rico, as well as inter-national students. There were also many opportunities to get career advice and opportunities for job shadowing (very helpful!!) Rice University dorms are awesome! Negative aspects include repetitiveness in lab experiments but this may be true of many types of research. Houston is also very hot in the summer but there is a lot to see there.

~Lalitha Kunduru ‘11 is a Biochemistry major and worked in the Etcheverry Lab at the Baylor College of Medicine this summer.

Summer Fellowship Deadlines1. Summer Undergraduate Research Fellowship (SURF) DEADLINE: February 26, 2009

SURFs are major awards (at least $3000) to enable undergraduates to engage in research, scholarship or creative performance under the guidance of faculty advisors (and possibly also graduate student mentors) for at least 9 weeks (20 hours/week) during the summer.

2. Science and Math Achievement and Resourcefulness DEADLINE: March 16, 2009Track Program (SMART)The SMART program provides an excellent, paid (~$3000) opportunity for rising sophomores to spend eight weeks during the summer doing 20 hours of research per week with a faculty mentor. SMART is sponsored by the National Science Foundation and is a part of its nationwide Alliance for Minority Participation initiative to increase the number of underrepresented minority students who earn degrees in science, technology, engineering, and mathematics (STEM) disciplines.

NEED $$$ FOR A SUMMER IDEA?

Undergraduate Summer Research Spotlights

“If we knew what it was we were

doing, it would not be called research,

would it?”~Albert Einstein

Carolina Scientific Fall 2008Front Cover: A 4-day old Lincoln’s sparrow, credit: Elizabeth Bergen

This publication was funded at least in part by Student Fees which were appropriated and dispersed by the Student Government at UNC-Chapel Hill.

Documents

Fall 2008 Issue