Bridging math, biology and ecology

Josh Keller, hiking in Austria, loves exploring the outdoors, as well as different scientific fields.

“As long as I can remember, I’ve enjoyed working on analytical puzzles,” says Josh Keller, an Emory senior majoring in math and linguistics and a Rhodes Scholar finalist. He hopes to spend his career solving health puzzles at the intersection of math and biology, and also help others understand those results.

“Many people don’t have the familiarity with numbers that comes naturally to me,” he says, “but numeracy is a critical ability for everyone in modern society.”

Keller spent part of his freshman year conducting research in a chemistry lab. “I was deliberate about exploring a lot of different areas,” he says, explaining how he expanded upon his interest in math and discovered his passions for language, ecology and the environment, and human health.

In his junior year, Keller joined a project modeling the transmission patterns of dengue fever. For his honors thesis, he is applying partial differential equations to epidemiological data, to try to improve models for tracking the spread of rabies in raccoons.

Building bridges between math, epidemiology and ecology can help control the spread of all kinds of infectious diseases, from rabies to deadly strains of influenza, he says. “I want to investigate and model practical biological issues with profound detail. But I also plan to be an instructor and a public figure who can relay that information in a helpful and meaningful way.”

Keller has served as a math tutor, a teacher’s assistant for linguistics, a freshman peer advisor and a leader of Bible study groups. He is president of Emory’s Wesley Fellowship and has participated in the Ethics and Servant Leadership Forum and the Open Door Community, which provides assistance to the homeless.

A Goldwater Scholar, Keller was inducted into Phi Beta Kappa his sophomore year. He has received high departmental awards in math and computer science, as well as in German – a rare honor for a non-major.

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Diapers yield developmental data

By Robin Tricoles

With the help of babies and more than 5,000 of their diapers, Emory researchers have developed an accurate, noninvasive way to determine estrogen levels in infants. The method, described in the journal Frontiers in Systems Biology, will allow comparisons of estrogen levels in human infants and their long-term reproductive development as well as the development of sex-specific behaviors, such as toy preference or cognitive differences.


What’s more, the method will allow researchers to look at how early disruption of the endocrine system affects long-term maturation, a growing concern among physicians.

Surprisingly little is known about hormone levels during human infancy. Previous human research has focused on the measurement of hormones in blood, urine and saliva. The new data are the result of using fecal samples collected from cotton diapers. With this novel approach, the researchers successfully measured the fecal levels of estradiol, a type of estrogen.

The well-known importance of estradiol’s role in postnatal development of the body, brain and behavior has in recent years raised specific concerns about how exogenous estrogens, or environmental estrogens, such as those found in soy, fruits and vegetables, plastics and common household items, affect lifelong health.

“The development of robust, noninvasive methods to measure these hormones in infants allows us to further investigate the association between postnatal hormone production and the development of sex-specific biology and behavior,” says Emory anthropologist Michelle Lampl, senior author of the paper.

“The development of an assay to measure estrogen from diapers might initially strike one as unnecessary or strange, but the need is real,” says Sara Berga, chair of gynecology and obstetrics at Emory’s School of Medicine. “We understand very little about the hormonal dynamics that occur during early development precisely because we lack a reliable way to track hormones in neonates and very young children. Having a way to track this critical hormone that influences behavior and the development of many important tissues, including the brain, will allow us to understand normal. This really is a great leap forward.”

The paper’s authors include anthropologist Amanda Thompson at the University of North Carolina, Chapel Hill; Emory anthropologist Patricia Whitten; and Michael Johnson of the University of Virginia Health System.

Previous studies in primates have shown a close parallel between fecal levels of estradiol and serum values. Likewise, a comparison of fecal steroid levels between the study infants and previous studies of human adults shows an overlapping pattern, a pattern that is also seen in infant serum when compared with adult serum.

“These observations are the first report of human infant fecal estradiol levels and they provide a new tool for investigating early human development,” Lampl say, who also serves as associate director of the Emory/Georgia Tech Predictive Health Institute. “Because infant diapers are plentiful, fecal samples can be collected frequently and over a long period of time. Future longitudinal studies will allow the association between fecal levels of steroids and physiological measures to be assessed, and expand our understanding independent of serum measures.”

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Explorer of the 'cool universe'

Artist's impression of the Herschel space telescope, which is revealing a surprising array of activity in cold, dark regions where interstellar material condenses. Credit: ESA, D. Ducros.

Emory astrochemist Susanna Widicus Weaver will soon begin one of the first broad spectral surveys of small organic molecules in deep space. Her lab’s research proposal – to search for the raw materials of life in star-forming regions – recently won 42 hours of observing time on the Herschel Space Observatory.

“The process for applying is incredibly competitive, and 42 hours is a huge amount of time, so we’re ecstatic,” Weaver said. “I actually watched the Herschel instrument evolve over the past 10 years, so I have to pinch myself that this is actually happening.”

Astrochemistry draws on astronomy, laboratory spectroscopy and chemical modeling to study chemical mechanisms in space. Weaver is skilled in all three of these specialized areas.

Weaver studies chemical mechanisms in space.

As a graduate student at Caltech, she would visit the NASA Jet Propulsion Laboratory and marvel at the technology going into building the Herschel instruments. Headed by the European Space Agency, Herschel became the largest telescope in space when it launched last year. The scope’s 3.5 meter-diameter mirror offers an unprecedented view of the “cool universe,” the domain of objects like tiny stars and molecular clouds that barely emit light. It may not seem as glamorous as looking for new planets, but scientists believe that the cool universe holds secrets for how life forms. Herschel operates in the far-infrared range, penetrating the veil of gas and dust shrouding these cooler realms by bridging the gap between infrared and radio astronomy.

Weaver’s research is focused on that gap, in the terahertz frequency range. At Emory, she is developing the technology to search for the building blocks of life in this largely unexplored area of deep space. Students are helping her build a high-sensitivity spectrometer to record the terahertz transmission frequency of transient molecules that are key building blocks to forming simple molecules of sugars and amino acids.

Weaver theorizes that these transient molecules are present in deep space. On Earth, however, they are unstable, existing only for the blink of an eye. So Weaver is developing methods to make the molecules and keep them stable in a laboratory environment. Using spectroscopy to record the spectral “fingerprints” of the molecules gives the lab a guide to search for them in space.
Stellar pregnancy and birth in the Milky Way. Credit: ESA/HiGAL Cosortium.

Weaver and her students are frequent visitors to the Caltech Submillimeter Observatory on the Mauna Kea volcano of the Big Island of Hawaii, where they acquire terahertz spectra with a 10.4-meter radio astronomy dish. This dish is a powerful device, situated in a high, dry and dark location, but observations are still hampered by the Earth’s atmosphere, which blocks most far-infrared wavelengths, while also producing its own far-infrared radiation. Observing terahertz radiation from the ground is like trying to see stars on a cloudy night.

“That’s the reason that the Herschel telescope is so incredible. This is the first time we can observe molecules in the terahertz range from space,” Weaver says.

Weaver and her students will use their time on the Herschel observatory to search for a range of simple molecules that they have identified as key to prebiotic pathways in interstellar chemistry, such as acetic acid, methyl formate, glycolaldehyde and methanol.

“Most previous observations have targeted a few specific molecules, but we want to open that up and get a better idea of the average composition of the clouds in star-forming regions,” Weaver explains.

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Tapping secrets of the social brain

Gary Stix writes in Scientific American:

Emory University just announced at this week's Society for Neuroscience meeting that it is establishing a Center for Translational Social Neuroscience.

The objective will be to bring in bigwig scientists like psychologist Frans de Waal from the school's Yerkes National Primate Research Center to marshal a body of basic research on social bonding and translate it into drugs or behavioral interventions that can help autistic children and those suffering from the kinds of social deficits that can occur with schizophrenia. These studies will also shed light on how the normal social brain works.

"The overall goal is to foster collaboration between people trying figure to out how to treat autism patients and people who are working with animals who can come up with clever ways of stimulating the social brain and bring these people together to make translation happen," says Larry Young, the center's director, who uses prairie voles (unusual because they are monogamous mammals—see photo) to study social relationships.

Read the whole article in Scientific American.

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Entering the era of living machines

Imagine being able to program an innocuous organism to clean up hazardous waste. Or generate a clean, cheap fuel. Or destroy cancer cells.

Emory scientists are among those working at the forefront of synthetic biology – the engineering of biological functions and systems not found in nature. This rapidly accelerating field holds tremendous promise, but raises challenging questions about ethics, security and safety.

Have an interest or concern about synthetic biology? Now is the time to express it. On Nov. 16-17, Emory is hosting a public meeting of the Presidential Commission for the Study of Bioethical Issues. (Watch videos of the event by clicking here.) It’s the third and final meeting of the commission before it issues recommendations to President Obama on synthetic biology.

“We look for a good turnout from interested members of the public, as well as teachers, students and practitioners in fields that touch on synthetic biology,” said Emory President James Wagner, vice chair of the commission.

If you are unable to attend, you can still have your say. Written comments on the topic can be emailed to info@bioethics.gov.

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