Duke Research Blog

Following the people and events that make up the research community at Duke.

Author: Guest Post

Understanding the Universe, Large and Small

From the miniscule particles underlying matter, to vast amounts of data from the far reaches of outer space, Chris Walter, a professor of physics at Duke, pursues research into the great mysteries of the universe, from the infinitesimal to the infinite.

Chris Walter is a professor of physics

As an undergraduate at the University of California at Santa Cruz, he thought he would become a theoretical physicist, but while continuing his education at the California Institute of Technology (Caltech), he found himself increasingly drawn to experimental physics, deriving knowledge of the universe by observing its phenomena.

Neutrinos — miniscule particles emitted during radioactive decay — captured his attention, and he began work with the KamiokaNDE (Kamioka Nucleon Decay Experiment, now typically written as Kamiokande) at the Kamioka Observatory in Hida, Japan. Buried deep underground
in an abandoned mine to shield the detectors from cosmic rays and submerged in water, Kamiokande offered Walter an opportunity to study a long-supposed but still unproven hypothesis: that neutrinos were massless.

Recalling one of his most striking memories from his time in the lab, he described observing and finding answers in Cherenkov light – a ‘sonic boom’ of light. Sonic booms are created by breaking the sound barrier in air.  However, the speed of light changes in different media – the speed of light in water is less than the speed of light in a vacuum — and a particle accelerator could accelerate particles beyond the speed of light in water.  Walter described it like a ring of light bursting out of the darkness.

In his time at the Kamioka Observatory, he was a part of groundbreaking neutrino research on the mass of neutrinos. Long thought to have been massless, Kamiokande discovered the property of neutron oscillation – that neutrinos could change from flavor to flavor, indicating that, contrary to popular belief, they had mass. Seventeen years later, in 2015, the leader of his team, Takaaki Kajita, would be co-awarded the Nobel Prize for Physics, citing research from their collaboration.

Chris Walter (left) and his Duke physics collaborator and partner, Kate Scholberg (right), on a lift inside the Super-Kamiokande neutrino detector.

Neutrinos originated from the cosmic rays in outer space, but soon another mystery from the cosmos captured Walter’s attention.

“If you died and were given the chance to know the answer to just one question,” he said, “for me, it would be, ‘What is dark energy?’”

Observations made in the 1990s, as Walter was concluding his time at the Kamioka Observatory, found that the expansion of the universe was accelerating. The nature of the dark energy causing this accelerating expansion remained unknown to scientists, and it offered a new course of study in the field of astrophysics.

Walter has recently joined the Large Synoptic Survey Telescope (LSST) as part of a 10-year, 3D survey of the entire sky, gathering over 20 terabytes of data nightly and detecting thousands of changes in the night sky, observing asteroids, galaxies, supernovae, and other astronomical phenomena. With new machine learning techniques and supercomputing methods to process the vast quantities of data, the LSST offers incredible new opportunities for understanding the universe. 

To Walter, this is the next big step for research into the nature of dark energy and the great questions of science.

A rendering of the Large Synoptic Survey Telescope. (Note the naked humans for scale)

Guest Post by Thomas Yang, NCSSM 2019

Pursuing Smell as a Path Into the Brain

Although the mystery of how the brain works and grows is a massive puzzle to figure out, the hope is that piece by piece, we can start to work towards a better understanding.

A person’s (or fly’s) sense of smell, or their olfactory system, is one of these pieces.

Though olfaction may not be the first part of the nervous system to cross someone’s mind when it comes to how we understand the brain, it is actually one of the most complex and diverse systems of an organism, and there’s a lot to understand within it, says Pelin Volkan, an assistant professor of biology and neurobiology and investigator in the Duke Institute for Brain Sciences.

Pelin Volkan in her lab.

Volkan and her lab have been working with fruit flies to try to unfold the many layers of the olfactory system, or the, “giant hairball,” as Volkan calls it.

Though she has been doing this work for years, she didn’t begin with an interest in neuroscience. Volkan was more interested in genetics in college and didn’t really start exploring neurobiology and development until her master’s degree at a Turkish university, when she worked with rats.

Not keen on working with rodents as model organisms but sticking with them anyway, she moved from Turkey to UNC to get her PhD, where she strayed away from neuroscience into molecular biology and development. Eventually, she realized she had a stronger passion for neuroscience, and ended up doing a postdoc at a Howard Hughes Medical Institute lab at UCLA for six years.

There, she became interested in receptors and neuronal wiring in the brain, propelling her to come to Duke and continue research on the brain’s connections and development.

One of the main reasons she loves working with the olfactory system is the many different scientific approaches that can be used to study it. Bouncing between using genetics, evolution, development, molecular biology,and other areas of study to understand the brain, her work is never static and she can take a more interdisciplinary approach to neuroscience where she is able to explore all the topics that interest her.

 Volkan says she has never had to settle on just one topic, and new questions are always arising that take her in directions she didn’t expect, which is what makes her current work particularly enjoyable for her.

“You have your stories, you close your stories, but then new questions come into play,” Volkan says. “And you have no choice but to follow those questions, so you just keep on going.”

And isn’t that what science is all about?

Guest Post by Angelina Katsanis, NCSSM 2019

An Indirect Path to Some Extreme Science

Dr. Cynthia Darnell’s path to becoming a postdoctoral researcher in the Amy Schmid Labat Duke University was, in her words, “not straightforward.”

Dr. Cynthia Darnell is a Postdoc at Duke, studying ‘extremophiles.’

At the start of her post-high school career, Darnell had no clue what she wanted to do, so she went to community college for the first two years while she decided. She had anticipated that she was going to go to college as an art major, but had always enjoyed biology.

While at community college she took a couple biology courses. She transferred to another college where she took a course in genetics and according to her, “it blew my mind.” While at the college she took a variety of different biology courses. Her genetics professor’s wife was looking for a lab technician in the microbiology lab she ran. After Darnell worked there for two years, she decided to go to graduate school and had a whole list of places/universities she could attend.

However, after going to a conference in Chicago and meeting her future graduate advisor, Darnell made the decision to go to Iowa for six years of Graduate school. She ended up in the Schmid Lab at Duke University for her “postdoc” after her boss had recommended the lab to her.

Previously, Darnell had done research on the connectedness of genetic pathways in halophilic extremophiles — bacteria that lived in extremely salty conditions. She developed projects to understand the how their genetic network sends and receives signals.

Darnell is continuing that research at Duke while also looking at the effects of different environmental factors on growth and the genetic network using mutant halophilic extremophiles.

Darnell with some plated archaebacteria in her Duke lab

There are generally three different paths Darnell’s day in the lab can take. The first path is a bench day. During a bench day, she will be doing experiments looking at growth curves, microscopes or RNA extracts. The second path is a computational day in which she will do sequencing to look at gene expression. The third option is a writing day in which she spends a majority of her time writing up grants, papers, and applications.

Dr. Darnell wishes to open up her own lab in the future and serve underprivileged students in underserved areas. She wishes to do more research in the area of archaebacteria because of how under researched and underrepresented it is in the scientific community. Dr. Darnell hopes to study more about the signaling networks in archaebacteria in her own lab someday.

She especially wishes to be able to open her lab up to underprivileged students, exposing them to the possibilities of research and graduate programs.

Guest Post by Tejaswi Siripurapu, NCSSM 2019

Finding Success in Science and the Economic Brain

How can we understand how humans make decisions? How do we measure the root of motivation?

Gregory Samanez-Larkin, an assistant professor in Psychology & Neuroscience at Duke, uses neuroeconomic and neuromarketing approaches to seek answers to these questions. He combines experimental psychology and economics with neuroimaging and statistical analysis as an interdisciplinary approach to understanding human behavior.

Gregory Samanez-Larkin 

From studying the risk tendencies in different age groups to measuring the effectiveness of informative messages in health decision-making,Samanez-Larkin’s diverse array of research reflects the many applications of neuroeconomics.

He finds that neuroeconomic and neurofinance tools can help spot vulnerabilities and characteristics within groups of people.

Though his Motivated Cognition & Aging Brain Lab at Duke, he would like to extend his work to finding interventions that would encourage healthier or optimal decision-making. Many financial organizations and firms are interested in these questions.

While Samanez-Larkin has produced some very influential research in the field, the path to his career was not a straightforward one.Raised in Flint, Michigan, he found that the majority of people around him were not very career-oriented. He found a passion for wakeboarding, visual art, and graphic design.

As an undergraduate at the University of Michigan-Flint, he was originally on a pre-business track. But after taking various psychology courses and assisting in research, Samanez-Larkin was captivated by the excitement and the advances in brain imaging at the time.

However, misconceptions about the field caused him to question whether or not going into research was the right fit, leading him to seek jobs in marketing and advertising instead. But in job interviews, he ended up questioning the methods and the ways companies explained the appeal of different ways of advertising. Realizing that he really enjoyed asking questions and evaluating how things work, he reconsidered pursuing science.

After a series of positive experiences in a research position in San Francisco, Samanez-Larkin began his graduate studies at Stanford University. The growing field of neuroeconomics — which combined his diverse set of interests in neuroscience, psychology, and economics — continued the “decade-long evolution” of Samanez-Larkin’s career.

Samanez-Larkin’s experiences in his career journey are reflected strongly in his approach to teaching.

“I feel like my primary responsibility is to help people become successful,” he says, as we sit comfortably on the sofas in his office.“Everything I do is for that.”

In his courses, Samanez-Larkin emphasizes the need to think critically and evaluate information, consistently asking questions like, “How do we know something works or not? How do I know how to evaluate if it works or not? How can I become a good consumer of scientific information?”

In his teaching, Samanez-Larkin hopes to set students up with usable, translatable skills that are applicable to any field.

Samanez-Larkin also hopes to support his students in the same way he received support from his previous mentors. “It’s cool to learn about how the brain works, but ultimately, I’m just trying to help people do something.”

Guest Post by Ariba Huda, NCSSM 2019

Tiny Bubbles of Bacterial Mischief

Margarethe (Meta) Kuehn studies vesicles — little bubbles that bud off bacterial membranes. All sorts of things may be tightly packed into these bubbles: viruses, antigens, and information a bacterium will need to make cells vulnerable to infection.

But why do bacteria produce these small membrane vesicles in the first place? Why not spread out to nearby cells themselves?

Jenny and Meta met last month on the Duke campus.

“The short answer is that we don’t know yet,” explains Kuehn, an associate professor of biochemistry at Duke. “But we speculate that it is due to their small size. These vesicles, which serve as delivery ‘bombs,’ can pass through pores that are too small for bacteria to fit through.”

Originally a chemistry major, Kuehn always had an interest in biochemistry. As an undergraduate, she worked in protein purification and then in the infectious disease division of a children’s hospital. There, she learned about pathogenic bacteria and how they secrete proteins to give themselves access to host cells.

Kuehn’s lab studies the mysterious world of bacterial vesicle production,focusing on the genetic, biochemical, and functional features of vesicles. So far, they have identified specific proteins and genes involved in the vesiculation process.

With a fine filter, they showed that vesicles can fit through holes to reach mammalian cells where a bacterium cannot.

Kuehn wonders why the bacteria don’t just use soluble proteins, which are even smaller than vesicles. They must have some reason for preferring the cell’s vesicles. Currently, they believe that vesicles can serve as nice packages — a whole bolus of information delivered together.

Basic anatomy of a vesicle, a bubble-like  membrane-bound package used by cells to move things around.

Not only will this new insight into extracellular vesicles of gram-negative bacteria aid in identifying new medicines, vesicles are also being used for vaccine delivery.

“They are really good antigen vehicles,” reveals Kuehn, “The more we know how they are made, the better we can design effective vaccines for humans.”

According to Kuehn, the amazing part about studying these pathogens is that, “You are never done. You never know it all. Every single pathogen, they each do things differently.” What keeps Kuehn going, she explains, is that the search never ends.

“There is never really a defined end point; you have to come to grips with the fact that you will never know that whole answer.”

Guest Post by Jenny Huang, NCSSM 2019

Biology by the Numbers

Michael C. Reed was trained as a pure mathematician, but from the start, he was, as he explained to me, a “closet physiologist.” He’s a professor of mathematics at Duke, but he’s always wondered how the body works.

Michael Reed in his office

Reed explains an example to me: women have elbows that are bent when their arms are straightened, but men do not. He rationalized his own explanation: women have wide hips and narrow shoulders; their bodies are designed so their arms don’t knock into their sides when they walk. (That basically ended up being the answer.)

Still, Reed never really explored his interest in physiology until he was 40 years old, when he realized that if he wanted to explore something, he should just do it. Why not? He had tenure by that point, so it didn’t really matter what his colleagues thought. He was interested in physiology, but was a mathematician. The obvious answer was mathematical biology.

Now he uses mathematics to find out how various physiological systems work.

In order to decide on a research project, he works with a biologist, Professor Fred Nijhout. They meet for two hours every day and work together. They have lots of projects, but they also just talk science sometimes. That’s how they get their ideas, mainly focusing on things in cell metabolism that have to do with important public health questions.

Reed has been investigating dopamine and serotonin metabolism in the brain, in a collaborative project with Nijhout and Dr. Janet Best, a mathematician at The Ohio State University.

Maybe better math is going to help us understand the human brain

As he explained to me, the brain isn’t like a computer; you don’t know how it works and there are a lot of systems in play. Serotonin is one of them. Low serotonin concentration is thought to be one of the causes of depression. There’s a biochemical network that synthesizes, packages, and transfers serotonin in the brain.

He told me that his work consists of making mathematical models for systems like this that consist of differential equations for concentrations of different chemicals. He then experiments with the system of differential equations to understand how the system works together. It’s not really something you can learn by having it explained to you, he told me. You have to learn through practice.

In a way, biology doesn’t seem like it would be the most compatible science, especially with math. But as Reed explained to me, “Math is easy because it’s very orderly and organized. If you work hard enough, you can understand it.” Biology, on the other hand, “is a mess.”

Everything in biology is linked to everything else in a system of connectedness that ends up all tangled together, and it can be hard to identify how something happens in the human body. But Reed applies math – an organized construct – to understand biological systems.

In the end, Reed does what he does because it’s how we — as human beings — work. He has no regrets about the choices he’s made at all.Mathematical biology seems to be his calling — he’s more interested in understanding how things work, and that’s what he does when he works.

Or rather, he doesn’t really work; because, as he told me,“try to find something to do that you really like, and are passionate about,because if you do, it won’t seem like work.” Reed doesn’t see coming into work as a struggle. He’s excited about it every single day and “it’s because you want to do it, it’s fun.”

Guest Post by Rachel Qu, NCSSM 2019

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