Negotiating uneven ground can be challenging for people who use lower-limb prostheses to walk, so researchers spend time searching for solutions that will allow greater stability in these situations. Manufacturers of prosthetic feet have contributed to a solution by adding multiaxial features that better reproduce the behavior of human ankles, which can stiffen as the terrain warrants. However, School of Biological Sciences Senior Lecturer W. Lee Childers found that there was a lack of evidence evaluating the prosthetic ankle stiffness as it relates to the user’s dynamic balance and gait over uneven terrain. Thus, his continuing research focuses on defining the effect of multiaxial stiffness on gait stability among people with unilateral transtibial amputations....“The main focus of this work was to justify that it is a good thing for prosthetic feet to have multiaxial function,” Childers says, because if it can prevent falls among its users, its value is demonstrated to the payers.
According to a study published by Georgia Tech researchers in the journal Scientific Reports, healthy people who take measures to avoid getting sick cannot fully eradicate the spread of disease without an infected individual taking preemptive steps first. Instead, the sick individual in question needs to take steps to avoid infecting anyone else, and the main motivator for taking those steps seems to be empathy -- the ability to understand the feelings of others. Ceyhun Eksin and Joshua S. Weitz collaborated on the study with a researcher from King Abdullah University of Science and Technology. Eksin is a postdoctorate fellow in Weitz's lab in the School of Biological Sciences.
Bees perform a crucial function for nature by pollinating crops. Now, researchers at Georgia Tech have explored how they keep themselves clean while dealing with that messy pollen.... David L. Hu, an associate professor who has a joint appointment in the School of Biological Sciences and the School of Mechanical Engineering, co-authored the study. Hu says this is the first quantitative analysis of how honeybees clean themselves and carry pollen using the 3 million hairs on their bodies. The study appeared in the journal Bioinspiration and Biomimetics.
The story of warring bacterial armies started as a Georgia Tech research published in February. Now it's a nationally distributed podcast produced by the National Science Foundation (NSF), and you can thank the researchers' unique mix of biology and math for inspiring NSF to tell the story widely in this format.
"The Discovery Files" recently highlighted the work of Brian Hammer, Will Ratcliff, Samuel Brown, and Peter Yunker in a 90-second radio feature titled "A Gut Reaction." The podcast is based on a paper published on Feb. 6, 2017, in the journal Nature Communications.
The researchers used math and physics equations to find patterns and consistency in how two competing armies of cholera bacteria attack each other. The work could someday help scientists develop targeted therapies using engineered microbes that could kill infectious, harmful bacteria while sparing helpful ones.
NSF, which helped fund the research, creates a weekly audio report on the latest scientific research. "The Discovery Files" airs on radio stations throughout the U.S.
You can listen to "A Gut Reaction" here.
Hammer and Brown are associate professors in the School of Biological Sciences. Ratcliff and Yunker are assistant professors, respectively, in the School of Biological Sciences and the School of Physics.
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Empathy is a crucial human ability. It’s the basis of the golden rule: do unto others as you’d have them do unto you. New research from Georgia Tech finds that empathy can help prevent the spread of disease during an outbreak. This segment on Georgia Public Broadcasting's "On Second Thought" program featured Ceyhun Eksin, a postdoctoral fellow in the lab of School of Biological Sciences professor Joshua S. Weitz. Eksin and Weitz collaborated with a researcher from King Abdullah University of Science and Technology.
Honeybees have almost three million hairs on their tiny bodies. Each hair is strategically placed to carry pollen and also to brush it off. Researchers at Georgia Tech used high-speed footage of tethered bees covered in pollen to see how these hairs work. David Hu, an assistant professor in the School of Biological Sciences, was a co-author of the study. The Georgia Tech Urban Honey Bee Project assisted in the research.
David Hu, an assistant professor in the School of Biological Sciences, has applied his expertise in the mechanics of interfaces between fluids such as air and water to the biomechanics of animal locomotion, publishing papers ranging from why frog tongues are so sticky to how fire ants form waterproof rafts....Hu, a 1997 graduate of Montgomery Blair High School Magnet in Montgomery County, Maryland, talks to the Magnet Foundation Newsletter about his experiences in the Magnet, how he became a professor, and his research today.
Raquel L. Lieberman is the recipient of the 2017 Georgia Tech Sigma Xi Best Faculty Paper Award. Lieberman is an associate professor in the School of Chemistry and Biochemistry. The paper recognized by this award is “Enzymatic hydrolysis by transition-metal-dependent nucleophilic aromatic substitution,” published in Nature Chemical Biology.
The work involves protein crystallography, enzymology, and organic chemistry to address a question related to chemical ecology. This diversity of fields exemplifies the highly interdisciplinary questions Georgia Tech researchers are aiming to answer.
Also notable is the diversity of Lieberman’s research team. It involved high school, undergraduate, and graduate students; a technician; and a postdoctoral fellow. Also with the team was a remarkable high school teacher whose teaching has been transformed by doing research in the Lieberman lab. The paper uniquely embodies Georgia Tech’s motto: Progress and Service.
The paper describes a precedent-setting metalloenzyme discovered in the context of the complex biochemical warfare waged in farm soils where potato is grown. In such soils, the bacterium Streptomyces scabies infects potato tubers and secretes compounds that induce the formation of scabs; among them is 5-nitroanthranilic acid (5NAA).
Also in the same soils is another bacterium, Bradhyrhizobium sp. This nonpathogenic microbe seems to defend itself and the potato plant from S. scabies by detoxifying 5NAA. Lieberman’s collaborator of more than five years, Jim C. Spain, in the School of Civil and Environmental Engineering, discovered the unusual metalloenzyme in this bacterium.
The enzyme – 5-nitroanthranilic acid aminohydrolase (5NAA-A) – performs unusual chemistry: hydrolysis of a nitroaromatic compound. Nitroaromatic compounds are notoriously toxic, challenging to synthesize, and difficult to degrade, but are found widely in synthetic dyes, explosives, and pesticides.
The Lieberman team solved the structure of 5NAA-A and investigated its enzyme mechanism, substrate specificity, metal-binding properties, and phylogeny. They found that the chemistry it mediates, and the mechanism it uses, is rare among known enzymes.
A major force in the work was Casey Bethel, who is Georgia’s 2017 Teacher of the Year (TOTY). Bethel helped pave the way to solving the crystal structures of 5-NAA-A and mentored students who helped confirm its unique chemical properties.
A highly charismatic high school teacher, Bethel has spent the past six summers working in the Lieberman lab. His participation was made possible by Georgia Intern Fellowships for Teachers (GIFT), a program administered by the Center for Education Integrating Science, Mathematics, and Computing. Funds from Lieberman’s NSF CAREER award sponsored Bethel for four of the six years.
“It’s rare – we believe unprecedented! – in Georgia for the TOTY award to go to a STEM teacher at the high school level,” Lieberman says.
“On behalf of my co-authors, I thank Sigma Xi and Georgia Tech for this honor,” Lieberman says. “Not only does our discovery have impact from a number of scientific angles; our study also truly epitomizes the interdisciplinary and collaborative culture at Georgia Tech."
What can microorganisms teach us about climate change?
Plenty, because microbes respond, adapt, and evolve faster than other organisms. Scientists can discover how microorganisms will change because of global warming more quickly than is possible for complex organisms. Understanding how microbes respond to climate change will help predict its effects on other forms of life, including humans.
Yet our understanding of microbes’ complex functions in ecosystems and their interaction with a warming planet is incomplete. Filling the knowledge gaps is crucial, says a report just released by the American Academy of Microbiology and the American Geophysical Union. The report, based on a workshop of experts, underscores the importance of microbes in ecosystems buffeted by climate change and identifies priorities for future study.
In addressing climate change, it’s important to understand the importance of microbes in ecosystems, says Joel E. Kostka, a professor in the School of Biological Sciences and the School of Earth and Atmospheric Sciences. He was invited to the workshop for his expertise on microbes in terrestrial polar environments. Despite their size, microorganisms provide critical services to ecosystems, Kostka says. “Through activities that produce or consume greenhouse gases, microbes intimately impact Earth’s climate.”
Microbes are the decomposers, breaking down organic matter and recycling nutrients, Kostka says. “Literally, the clean air we breathe and the food we eat depend upon carbon and nutrient cycling – ecosystem services provided by microbes.”
However, the processes microbes mediate are complex and need to be better understood, Kostka says, “so we can make accurate predictions of how ecosystems will respond to climate change.”
One example of that complexity is plant-microbe interactions. Thousands of microbial species make up plant microbiomes – microbes that live inside or on plants. Microbiomes help plants grow better through nutrient acquisition among many functions. Conversely, microbes process organic matter produced by plants. How microbial communities will change due to Earth’s warming will depend on how plants respond and vice versa, Kostka says. To understand the effect of climate change on ecosystems, we have to know how plants and microbiomes interact or communicate.
Also highlighted by the workshop, Kostka says, is the need for communication across scientific disciplines. “I found myself informing the chemists on the latest information we have on microbes and microbial activity in wetlands, for example.”
The report is intended for the public, educators, and the broader science community, Kostka says. “I would hope that it represents a call to action for better understanding of microbiomes in the environment.”
Somebody give David Hu's graduate and undergraduate students medals for bravery -- and maybe some hazmat suits. Hu, an associate professor in the School of Biological Sciences and an adjunct associate professor in the School of Physics, is a 2015 Ig Nobel Prize winner for his "urination duration" research, and he and his intrepid fluid dynamics team have also gotten hands-on (yuck) with frog saliva. Now he has studied the physics of poop among mammals, venturing to Zoo Atlanta to follow elephants around and figure out things like speed, duration, size, mucosity, etc. Hu, also an associate professor in the George W. Woodruff School of Mechanical Engineering, makes the connection between his research and a better understanding of gastrointestinal health. The research also helped his team design state-of-the-art undergarments for astronauts. Hu's study was published April 25 in the journal (wait for it)....Soft Matter.