Wednesday, March 25, 2015

Physicist's research of glassy materials nets NSF CAREER award

Physicist Justin Burton at work in his lab, where he studies amorphous matter. (Emory Photo/Video)

By Carol Clark

Emory physics professor Justin Burton received a $625,000 award from the National Science Foundation’s Faculty Early Career Development (CAREER) Program. The five-year CAREER grants, among the NSF’s most prestigious awards, support scientists who exemplify the role of teacher-scholars through outstanding research integrated with excellence in education.

Burton will apply the award to his research into amorphous matter, or substances made up of granules in jumbled, irregular states. These substances include everything from the foam on your cup of cappuccino to the vast, slushy mélange of a glacier as it breaks down and flows into the sea. Amorphous matter also encompasses soft condensed matter such as toothpaste, shaving cream, plastic and glass, which are collectively known as “glassy” materials.

“Amorphous material is everywhere, it’s among the most common states of solid matter,” Burton says, “and yet, there’s a lot that we don’t understand about it.”

Crystalline material, by contrast, is relatively rare but well understood by physicists. Crystals have a structural order that makes them easier to conceptualize and define mathematically. “Research into the thermodynamic behavior of crystals at ultra-low temperatures led to our understanding of how they conduct heat,” Burton says. “That’s one of the fundamental triumphs of quantum mechanics. It helped lay the foundation for a lot of important tools of the modern world, from computers to cell phones.”

Lacking the well-defined order of crystals, amorphous materials often behave in peculiar, unpredictable ways. Burton uses the example of a pile of sand at the bottom of an hourglass. “What seems stable enough can suddenly avalanche upon the addition of a few extra grains,” he says. “Or even a traffic jam: What determines the boundary between a flowing state and a rigid one? Our world is full of similar examples where systems exist in a region near marginal stability.”

A view inside the vacuum chamber, where colloidal particles are suspended in a flat disc, lit by the green light of a laser. Photo by Justin Burton.

Burton’s lab is creating model systems to simulate the dynamics of the microscopic granules of amorphous, glassy matter at ultra-low temperatures of below 1 degree Kelvin. That’s colder than the deepest reaches of space.

In a vacuum chamber, filled with argon gas, the lab conducts experiments. The chamber is filled with ionized argon gas. “It’s a plasma, or a gas that has had its electrons ripped away from its atoms,” Burton explains. “The electrons are constantly being ripped away and resembling.”

Colloidal particles, tiny as dust specks, are suspended in the plasma of the vacuum chamber, to stand-in for the molecules of an amorphous material. By altering the gas pressure inside the chamber, and varying the size of the particles, the lab can study how the particles behave as they move between an excited, free-flowing state into a jammed, stable position.

They can also simulate how molecules in a stable position react to a disturbance. “We want to create a wave, like dropping a pebble into a still pond to make ripples, and study that dynamic,” Burton says. “That could help us understand, for instance, how sound moves through a glassy material.”

Burton’s lab will use another model, involving polymer hydrogel particles that expand or shrink in response to salt concentrations, to study Casimir forces, a special type of long-ranged force that can arise between objects in a highly fluctuating medium.

In addition to opening a window into the molecular motions common in glasses, the research could shed light on the connection between the dynamics and disorder in a broad range of physical systems, Burton says.

In parallel to his research effort, the CAREER award will also fund the creation of an after-school science club at an elementary school in Dekalb County. Burton and his graduate students will lead children in hands-on activities and experiments that give insights into basic principles of physics.

Related:
The physics of falling icebergs
Physicists crack another piece of the glass puzzle

Tuesday, March 24, 2015

Neuroethics and the human brain projects

Image from cover of the NIH brochure "The BRAIN Initiative."

The European Commission has promised 1 billion euros for its Human Brain Project, which seeks to build a computer model of the human brain within the next decade. And U.S. federal agencies are expected to contribute several billion dollars to President Obama's BRAIN Initiative (Brain Research through Advancing Innovative Neurotechnologies).

Meanwhile, the U.S. Presidential Commission for the Study of Bioethical Issues, which includes Emory’s President James Wagner as its vice chair, has outlined the need for ethical inquiry alongside this research. In a 2014 report entitled “Gray Matters: Integrative Approaches for Neuroscience, Ethics and Society,” the commission calls for a systematic ethics education throughout the careers of neuroscientists.

Articles in the current issue of the American Journal of Bioethics Neuroscience (AJOBN) represent the scope of ongoing neuroethical inquiry, from criteria for human trials to study Parkinson’s disease to the use of prescription stimulants to enhance motivation.

“The study of neuroscience, unlike many other scientific disciplines, resonates with the notion of who we think we are,” write the authors of an editorial in the issue. “Therefore, the ethical questions often move beyond research and professional ethics into the complex terrain of evaluating societal implications. This will impact how we educate our burgeoning neuroscientists.”

The editorial was co-authored by Karen Rommelfanger, director of the Neuroethics Program at Emory’s Center for Ethics.

“Ultimately, the success or failure of the human brain projects will be measured only partly by the extent to which they accomplish the goal of mapping the human connectome,’ the editorial authors conclude. “If the goal of the projects is to understand the human brain, the goal of neuroethics is to help understand and explain what understanding the brain would really mean.”

The ABJOBN is the official publication of the International Neuroethics Society and many of its editors are housed in Emory’s Center for Ethics.

Wednesday, March 18, 2015

Atlanta Science Festival offers formula for fun

Emory chemist Doug Mulford gets kids fired up for science during a demonstration at last year's Atlanta Science Festival. Emory Photo/Video

By Carol Clark

Start with a beaker as big as metro Atlanta. Add scientists, artists, music, dance, robots, games, movies, lab tours and chances to try new technology and conduct fun experiments. Throw in some liquid nitrogen ice cream, giant soap bubbles and Tibetan momos. Now mix with hundreds of enthusiastic volunteers and thousands of curious people of all ages. Finally, jump in yourself.

The Atlanta Science Festival is back, March 21-28, with its ever-evolving formula for fascination and fun. The eight-day celebration of local science and technology encompasses more than 120 events at 70 venues throughout Atlanta, including many on the Emory campus. The festival culminates in the Exploration Expo at Centennial Park on Saturday, March 28.

“We want to help our community become proud of the resources, research and discoveries happening here, and all the opportunities for careers,” says Jordan Rose, co-director of the festival and associate director of the Emory College Center for Science Education. “The more we can connect people to local scientists and their innovations, the more people can get excited about science in general.”

Last year, 30,000 people attended the week-long inaugural Atlanta Science Festival, including 16,000 who came to the Exploration Expo, which was chaired by Emory chemist Monya Ruffin. "It’s hard to predict attendance this year for all of the events over eight days, but we’re expecting at least 20,000 people for the Expo alone,” Rose says. “It’s going to be a busy day at the park.”

About 20 booths at the Expo will feature Emory science faculty and students. ChEmory, for example — the outreach group made up of Emory chemistry undergraduates — will return with its popular dance pit. Kids can kick their shoes off and experience moving to music through a non-Newtonian fluid.

Several events are scheduled on the Emory campus on Saturday, March 21, targeting both adults and children. You can find details about all the Emory events here.

Read more in Emory Report.

Monday, March 16, 2015

Taking hands-on mentoring to new heights


Click here, if video does not appear on screen.

By Marsha Walton, via AAAS

Emory biology professor Patricia Marsteller makes it clear to students of all ages that they can change the world at any time. And it doesn’t have to be a big gesture.

At the Center for Science Education (CSE), she helps create hands-on research and curriculum for students and teachers at the pre-college, college and postgrad levels. With one local grant, for example, her team of science educators worked with high school students to make connections between science and the arts.

Pat Marsteller
Another school wanted to use science to learn more about homelessness in metropolitan Atlanta. “The students actually went out and talked with homeless people under bridges, with help from grad students and teachers. But then they decided they wanted to do something about it. They used their science class to build little solar heaters for homeless people. So they could see right there where they could make a difference,” she said.

Marsteller, a AAAS fellow, joined the Emory faculty in 1990 with a focus on bringing more women and minorities to biology and medicine. Today, her mission has broadened to improving science education by mentoring learners from “K through gray.” And she says doing that well literally takes a “hands-on” approach.

One of her liveliest examples? On day one of the class Biology, Physics, Chemistry and Design Principles of Coffee and Beer, Emory students dissected the workings of coffeemakers rescued from yard sales. “We had them take them apart, and try to explain how they worked,” said Marsteller. “They were just astonished. None of them had ever done anything like that before. But it grabbed them.”

She says students who are academic stars—but who have never taken apart a tractor, car or other machinery—may be missing the problem-solving experience that’s crucial for developing a scientific mindset. “They can learn facts and spit them back at you, but that is not what we want them to do. We want them to find new ways of doing things. The science changes all the time and they need to learn to investigate claims on their own,” she said.

Marsteller grew up on a farm in Pennsylvania, the oldest of 11 children. All those siblings and animals gave her plenty of chances for hands-on, unscripted learning. Although she was first headed toward a career as a physician, her interest began shifting toward research and science education after a discouraging undergraduate experience. “I encountered some really bad teaching,” she said.

Her search for her own scientific future became a wide one, ranging from clinical research in pediatric cardiology to analyzing cattle nutrition.



But it was volunteer work with alligators at the Savannah River Ecology Laboratory in South Carolina that intrigued her so much that it galvanized her scientific focus on research and teaching. She studied evolution of animal behavior and genetics for her graduate degrees, including the study of an alligator’s ability to use celestial navigation. “We kept finding that if you relocated an alligator, even hundreds of miles away, they would find their way back home. Well, how do they do that?” she said.

Her own captivation with reptile research early in her career inspires her to guide students to find their passion, even if it takes them in a whole new direction from where they started. She describes herself as a “change agent” and “transformer.”

As director of CSE, she helps undergraduates with that quest with a simple exercise. “It’s like a Venn diagram. There are three circles: What are you good at? What do you like to do? What will make a difference in the world?”

She says students who soar in the sciences often are channeled into medical careers, for financial security or to make their parents happy. She stresses that scientists in other specialties can make practical things happen through research.

One of her proud creations is the SURE program, the Summer Research Experience at Emory. Undergrads from Emory and other schools are paired with grad students for summer projects. Most go on to succeed in graduate programs.

While attracting women and underserved students has shown success, Marsteller says creating diversity among science faculties has been painfully slow and frustrating. “People on the search committees write to their friends, and their friends all look like them,” she said, adding that more of an effort needs to be made by major institutions to stay in touch with successful alumni with PhDs and bring them back to join the faculty.



Marsteller is convinced that mentors are the key to success at every level of STEM education. “There needs to be a kind of cascade of mentoring, from faculty to postdoc to undergrad to high school. And not just for research, but for professional development, for strategy in launching a career,” she said.

Marsteller also helps her students bring scientific understanding to the public about some of today’s critical issues, including climate change, population growth and sustainable energy. She encourages them to reach out in coffee shops, bars, or botanical gardens. She says podcasts, websites, and public talks have just “taken off” with popular support. “I think we can engage people from all walks of life into thinking about these issues,” she said.

Whether it is staring down a baby alligator, reimagining a coffeemaker, or embarking on a nontraditional scientific quest, Marsteller is a vocal advocate and example of the rewards of following the path that is most inspiring. “Students need that nourishing and pushing a little bit,” she said.

Copyright by AAAS, used with permission.

Related:
Cultivating brains for science
Bringing new blood to high school science

Tuesday, March 10, 2015

Disease poses risk to chimpanzee conservation, Gombe study finds

Gombe is the site where Jane Goodall conducted her pioneering research into the behavior of wild chimpanzees, beginning in 1960. "If we’re going to keep these iconic chimpanzees on the planet, we need to address the spread of infectious diseases," says disease ecologist Thomas Gillespie.

By Carol Clark

Infectious disease should be a key consideration in wildlife conservation, suggests a study focused on primates in Tanzania’s Gombe Stream National Park, published by PLOS Neglected Tropical Diseases. The study investigated the parasite Cryptosporidium and cross-species transmission risks among humans, wild primates and domesticated animals within the greater Gombe ecosystem.

“We found that people are likely exposing the endangered chimpanzees of Gombe to a particular species of Cryptosporidium, which may be contributing to their decline,” says Michele Parsons, a PhD student in Emory University’s departments of Environmental Sciences and Environmental Health. “It appears to be a case of spillover, or exchange of a pathogen, from humans to animals, instead of the other way around.”

The spillover of any one pathogen between species, Parson adds, “is an indicator that an ecological connection exists, with potential for other pathogens to emerge.”

The study also revealed that some of the chimpanzees are infected with a species of Cryptosporidium associated with pigs. “No domesticated pigs reside in the village just outside the park, so we think it’s likely that the source of infection is wild pigs living in the forest,” Parsons says.

In addition to being a student in Emory’s Population Biology, Ecology and Evolution Graduate Program, Parsons is a research microbiologist at the Centers for Disease Control and Prevention’s Division of Foodborne, Waterborne and Environmental Diseases. She led the study with her PdD adviser, disease ecologist Thomas Gillespie, a professor in Emory’s Department of Environmental Sciences and Rollins School of Public Health’s Department of Environmental Health.

“When it comes to protecting endangered species, the focus is often limited to providing habitat and preventing hunting,” Gillespie says. “But disease also matters in conservation, and that’s a relatively new message. Our research shows that if we’re going to keep these iconic chimpanzees on the planet, we need to address the spread of infectious diseases.”

Gombe is the site where Jane Goodall conducted her pioneering research into the behavior of wild chimpanzees, beginning in 1960. Goodall’s project is now the longest field study of any animal. Each individual chimpanzee has been identified, and its maternal line is known.

Despite the fact that Gombe became a protected wildlife park in 1968, the chimpanzee population there is on the decline, down from about 150 chimpanzees 20 years ago to 100 today.

Emory disease ecologists Michele Parsons and Thomas Gillespie in the field in Gombe.

The Gillespie lab is one of the few investigating the ecology and epidemiology of infectious disease in natural systems where domesticated animals, humans and wildlife overlap.

Cryptosporidium, or "Crypto," is one of the most frequent causes of waterborne disease in the United States, and is among the top four cases of moderate-to-severe diarrheal disease in young children in developing nations. Crypto is particularly dangerous for people infected with HIV, who tend to have more severe cases that can be fatal. Studies have also shown that chimpanzees infected with SIV (the ancestor of HIV) have a reduced lifespan and may be more vulnerable to opportunistic infections.

The researchers collected fecal samples from a cross-section of chimpanzees, baboons, humans, and domesticated dogs, goats and sheep within the greater Gombe ecosystem. The results revealed Crypto infection rates of about 16 percent in the wild primates, 4 percent in humans and 10 percent in the goats and sheep.

DNA sequencing uncovered a complex epidemiology for Crypto in this system, with humans, baboons and a subset of chimpanzees infected with C. hominis (which is most closely associated with humans), and another subset of chimpanzees infected with C. suis, (usually associated with pigs). All the positive sheep and goats were infected with C. xiaoi (a subtype associated with livestock).

“The dominance of C. hominis among humans and non-human primates suggest cross-species contamination,” the study authors write.

The research team gathers stream water samples for analysis.

The baboons are known to raid human homes and trash for food, while the chimpanzees raid agricultural fields just outside the park boundaries. These behaviors expose the wild primates to the potentially contaminated feces of livestock or exposed human sewage.

Although water samples screened in the study were negative for Crypto, waterborne outbreaks of Crypto as a result of human and animal fecal contamination are common. “Homes with positive livestock had a tendency for increased risk of human infection, suggesting contribution of environmental factors or behaviors that may place the household at increased risk,” the study authors write.

The findings highlight the complex nature of zoonotic parasite transmission and stress the need for further studies, Parsons says. “It’s important to understand the ecology of diseases for both wildlife conservation and for human health. We need good baseline data in order to monitor emerging pathogens.”

Co-authors of the study include researchers from the University of Minnesota, Franklin and Marshall College, the Jane Goodall Institute and the Henan Center for Disease Control and Prevention.

Photos courtesy of Thomas Gillespie and Michele Parsons

Related:
Ebola's back story: How germs jump species
Sanctuary chimps show high rates of drug-resistant staph