Wednesday, May 16, 2018

Chemistry students sing their studies, hoping for a good reaction

By Carol Clark

On the last day of the spring semester, during Bill Wuest’s “Principles of Reactivity” course, loud noises rattle the Atwood Chemistry Center’s Atomic Classroom. It isn’t explosions — it’s pop music mixed with bursts of laughter.

“This bond’s alright!” a group of Emory first-year students belts out on a YouTube video playing on screens before the class. Backed by the music of “Oh, What a Night,” they dance before a periodic table, write on a white board and mix chemicals in a lab while singing lyrics they wrote themselves: “Now I use a base to synthesize. It can readily be hydrolyzed. Mechanisms, what a sight!”

In just under four minutes, the students sing key lessons they learned over the semester about carbonyl mechanisms.

“It’s basically describing how reactions go,” explains Rebecca Henderson, one of the performers. “A reaction is not normally just putting two chemicals together and — BOOM — a product comes out. There’s a lot of different steps involved and we wanted to describe some of them, and why a reaction goes down one pathway and not another.”

Henderson created the video with classmates Carson Brooks, Lauren Cohen, Justine Griego and Alex Kim. They all played themselves in the video — except for Kim, who used powder to create a white patch in his hair and portray the professor.

“I love it when they mock me, they get extra points for that,” says Wuest, who has a natural, white streak of hair running through the center of his close-cropped dark hair.

Wuest, who joined Emory in the fall of 2017 as a Georgia Research Alliance Distinguished Investigator, directs an organic chemistry lab along with teaching undergraduates. He started having students make music parody videos while he was at Temple University.

“A lot of people think that chemistry is dry and boring but there’s a lot of creativity involved in it and that’s often overlooked in classrooms,” Wuest says.

The videos fit in well with Emory’s curriculum. Last fall, Emory became one of the first major research universities to completely overhaul how chemistry is taught, from introductory courses to capstone seminars. The new program, called Chemistry Unbound, moves away from teaching a narrow slice of chemistry every year to jumping into a big-picture understanding of chemistry’s central role across the sciences.

The video assignment helps with those big-picture concepts, Wuest says. Students form groups of up to six to make a two-to-four-minute educational video about some aspect of what they’ve learned in class. The video can either take the form of a musical parody of a well-known song or — for the less adventurous — a more straightforward lesson in the style of the Khan Academy website.

While Wuest is not the first to have chemistry students make videos, he is one of the few to actually measure their effect. With the help of his wife, Liesl Wuest, an educational analyst who also works at Emory, he has compared learning outcomes — in the form of exam performance before and after the videos — and found a strong correlation to improved scores.

His Temple students received extra credit, but not a grade, for making videos. Out of 130 students, 25 percent of them opted to do the videos. The average score for the class on an exam before the video project and an exam following the video project found that those who made videos had an average of 50 percent more improvement in their scores compared to those who opted out.

“Making the videos forces students to think about the material in new ways,” Wuest says. “It also makes the material more memorable to help it stick with them long term.”

Wuest refined the criteria for the video project and turned it into a graded requirement for his Emory classes. The top videos, based on accuracy and execution, will be housed on the Canvas learning management system so that future students can use them for inspiration and study aids.

“I was really impressed with the level of the videos this semester,” Wuest says. “They showcase the quality and the diversity of the students at Emory.”

Wuest plans to continue measuring the effect of the videos on learning. Many of the students, meanwhile, have given the video assignment a big thumb’s up.

“Not only do you learn the material, but it’s a fun experience,” says Dennis Jang, a first-year student.

Jang helped make a video called “I’ll Make a Chemist Out of You,” set to the song “I’ll Make a Man Out of You” from the Disney movie “Mulan.” The other first year students in his group included Muhammad Dhanani, Alex Fukunaga, Gaby Garcia and Jessie Kwong.

“The hardest part of this project was balancing the content and the comedy,” Jang says. “We presented some broad aspects of what we learned in class and some more specific aspects. And then we added humor to keep the audience watching.”

The formula worked. An informal vote following the screening of the videos in class, based on laughter and applause, showed “I’ll Make a Chemist Out of You” was the clear audience favorite.

“As we were watching all of the videos together we were laughing and just really enjoying being together,” Henderson says. “It was the final wrap-up of a great semester. Bill really knows how to make a true community out of a classroom.”

You can watch more of the videos by clicking here. 

Chemistry synthesizes radical overhaul of undergraduate curriculum

Monday, May 14, 2018

Study reveals how the brain decides to make an effort

"Understanding how the brain works normally when deciding to expend effort provides a way to pinpoint what's going on in disorders where motivation is reduced," says Emory psychologist Michael Treadway, whose lab conducted the study.

By Carol Clark

From deciding to quit hitting the snooze button and get out of bed in the morning to opting to switch off the TV and prepare for sleep at night, the mind weighs the costs versus benefits of each choice we make. A new study reveals the mechanics of how the brain makes such effortful decisions, calculating whether it is worth expending effort in exchange for potential rewards.

The Proceedings of the National Academy of Sciences (PNAS) published the findings by psychologists at Emory University.

“We showed that the brain’s ventromedial prefrontal cortex, which was not previously thought to play a key role in effort-based choices, actually appears to be strongly involved in the formation of expectations underlying those choices,” says Emory psychologist Michael Treadway, senior author of the paper.

Treadway’s lab focuses on understanding the molecular and circuit-level mechanisms of psychiatric symptoms related to mood, anxiety and decision-making.

“Understanding how the brain works normally when deciding to expend effort provides a way to pinpoint what’s going on in disorders where motivation is reduced, such as depression and schizophrenia,” he says.

Previous research had observed three brain regions in decision-making; the dorsal anterior cingulate cortex (dACC), the anterior insula (aI) and the ventromedial prefrontal cortex (vmPFC). Studies had pointed to the vmPFC as central to the computation of subjective value during probability decision-making. But prior evidence also suggested that when it comes to decisions about effort expenditure, those subjective value estimates were not computed by the vmPFC but by the other two brain regions.

A limitation to previous studies on effort-based choices is that they simultaneously presented the costs and benefits of a choice to experimental subjects.

“In the real world, however, we usually have to make decisions based on incomplete information,” says Amanda Arulpragasam, first author of the PNAS paper and a psychology PhD candidate in Treadway’s lab.

Arulpragasam designed a study that allowed the researchers to model distinct neural computations for effort and reward.

Subjects underwent functional magnetic resonance imaging (fMRI) while performing an effort-based decision-making task where the effort costs and rewards of a choice were presented separately over time.

The subjects could choose to make no effort and receive $1, or make some level of physical effort in exchange for monetary rewards of varying magnitude, up to $5.73. The physical effort involved rapid button pressing at varying percentages of each participant’s maximum button pressing rate. Participants were required to press the button using their non-dominant pinkie finger, making the task challenging enough to be unpleasant, although not painful.

In the effort-first trials, participants were shown a vertical bar representing the percentage of their maximum button pressing rate that would be required to do the task. They were then shown the size of the reward for performing the task. The reward-first trials presented the information in the opposite order.

After receiving both sets of information, participants were prompted to choose the no-effort option or the effort option.

The experimental design allowed the researchers to tease apart the effects of recent choices on the formation of value expectations of future decisions.

The results revealed a clear role for the vmPFC in encoding an expected reward before all information had been revealed. The data also suggested that the dACC and aI are involved in encoding the difference between what participants were expecting and what they actually got, rather than effort-cost encoding.

“Some have argued that decisions about effort have a different neural circuitry than decisions about probability and risk,” Treadway says. “We’ve showed that all three brain regions come into play, just in a different way than was previously known.”

Co-authors of the PNAS paper include Jessica Cooper, a post-doctoral fellow in the Treadway lab and Makiah Nuutinen, a research interviewer in the lab.

Twitter reveals how future-thinking Americans are and how that affects their decisions

Friday, May 11, 2018

Dengue 'hot spots' provide map to chikungunya and Zika outbreaks

A street scene in Merida, Mexico, a city of about one million in the Yucatan Peninsula where the study was based. Merida had a little over 40,000 reported dengue cases during 2008 to 2015 and nearly half of them were clustered in 27 percent of the city.

By Carol Clark

Identifying dengue fever “hot spots” can provide a predictive map for outbreaks of chikungunya and Zika — two other viral diseases that, along with dengue, are spread by the Aedes aegypti mosquito.

PLOS Neglected Tropical Diseases published the findings, the first confirmation of the spatial-temporal overlap for outbreaks of the three diseases, led by Emory University.

“We had hypothesized that we would see some overlap between these diseases, but we were surprised at the strength of that overlap,” says Gonzalo Vazquez-Prokopec, a disease ecologist in Emory’s Department of Environmental Sciences and lead author of the study. “The results open a window for public health officials to do targeted, proactive interventions for emerging Aedes-borne diseases. We’ve provided them with a statistical framework in the form of a map to guide their actions.”

The analysis drew from eight years of data from Merida, Mexico, on symptomatic cases. A city of one million located in the Yucatan Peninsula, Merida had about 40,000 reported dengue cases during 2008 to 2015, and nearly half of them were clustered in 27 percent of the city. The neighborhoods comprising these dengue hot spots contained 75 percent of the first chikungunya cases reported during the outbreak of that disease in 2015 and 100 percent of the first Zika cases reported during the Zika outbreak in 2016.

“Currently, most mosquito control efforts are not done until cases of mosquito-borne diseases are detected,” Vazquez-Prokopec says. “But by the time you detect a virus in an area, it has likely already begun to spread beyond that area.”

Mosquito control efforts generally involve outdoor spraying that covers broad swaths of a city, further reducing efficacy, he adds. Outdoor spraying is particularly ineffective for the Aedes aegypti mosquito. “This mosquito is highly adapted to urban environments,” Vazquez-Prokopec says. “It likes to live inside houses and to feed on people.”

A targeted approach would make it more feasible to implement time-consuming and costly interventions such as indoor residual spraying.

A technician sprays the ceiling and walls of a home in Merida. Indoor residual spraying is effective, but is not practical for large areas of a city, due to the time and expense involved. Photo by Nsa Dada.

“The statistical framework that we have developed allows public health officials to harness the power of big data to do more effective and efficient mosquito control by focusing on high-risk areas — even before an epidemic begins,” Vazquez-Prokopec says.

The study used disease case reports at the household level and then scaled them up to neighborhoods to protect individuals’ privacy in the final map. The hot spots for reported dengue cases were confirmed by data from laboratory blood tests of a cohort of 5,000 people. The analysis showed that people living in a dengue hot spot had twice the rate of infection of those outside of the hot spots.

The research team included scientists from the Autonomous University of Yucatan and health officials from the state and federal level in Mexico. Other members of the team were scientists from seven other universities and health research institutions, including the U.S. Centers for Disease Control and Prevention.

The researchers are now working with the Pan American Health Organization (PAHO) to develop a manual and training materials, based on open-access software, for mapping risks of Aedes-borne diseases to guide proactive interventions throughout urban areas of the developing world.

More than one third of the world’s population lives in areas at high risk for infection with the dengue virus, a leading cause of illness and death in the tropics and subtropics, according to the Centers for Disease Control and Prevention. Dengue fever is sometimes called “break bone fever” due to the excruciating pain that is among its symptoms.

The chikungunya virus emerged in the Americas in 2013, sweeping through many countries where dengue is endemic. Common symptoms of chikungunya infection may include headache, muscle pain, joint swelling and rash.

Zika virus followed in 2016, causing little alarm at first due to its relatively mild symptoms. It soon became apparent, however, that the Zika virus could cause birth defects in the babies of pregnant women who were infected.

“You tend to see transmission go down right after large numbers of a population are infected with these Aedes-borne viruses, leading to herd immunity,” Vazquez-Prokopec says. “But these viruses do not disappear. They keep circulating and can reappear later.”

Meanwhile, new Aedes-borne viruses are likely to emerge, he adds, as rapid urbanization and a warming climate help the mosquito thrive.

Vaccines are not yet available for chikungunya or Zika, and efforts to roll out a vaccine for dengue are complicated by the fact that the virus comes in different serotypes.

“Although effective vaccines would be the ultimate line of defense against these diseases, we cannot give up on mosquito control,” Vazquez-Prokopec says.

Contact tracing, with indoor spraying, can curb dengue outbreak
Zeroing in on 'super spreaders' and other hidden patterns of epidemics
Human mobility data may help curb epidemics

Monday, May 7, 2018

Bonding over bones, stones and beads

By Carol Clark

"I've really been into bones since I was little. I don't know why," says Emory University senior Alexandra Davis, an anthropology major. "Not fresh bodies, though. No soft tissues or blood. Just bones."

In fact, Davis loves bones so much that she was willing to spend seven weeks in Malawi with Emory anthropologist Jessica Thompson and four more of her students last summer, excavating bones and other artifacts in ancient hunter-gatherer sites, assisted by a team of locals.

Thompson will return to Malawi in July with another team of students to continue excavation of two sites that were started last summer. "We want to get into the deeper layers, because in both cases we did not come close to reaching the bottom of the sites," Thompson says. "Then, we want to find out how old they are."

Read more about the project.

Malawi yields oldest-known DNA from Africa
Have skull drill, will travel

Friday, May 4, 2018

'Dog-nition' research set for Science Friday

Come. Sit. Stay. And listen to Science Friday's interview at 3:30 pm E.T. today with Emory neuroscientist Gregory Berns, who is exploring the inner workings of the canine mind. Two of the questions the program plans to explore: Do dogs have a concept of time? And how do our furry companions make sense of the world?

You can tweet questions you'd like answered to @scifri. The radio program is based at WNYC Studios, distributed to public radio stations across the United States, and is also accessible online.

A dog's dilemma: Do canines prefer praise or food?
Recreating the brain of the extinct Tasmanian tiger

Tuesday, May 1, 2018

Emory chemistry receives $7.5 million to lead fuel cell research

"A deeper understanding of electrochemical processes is important in the quest for more efficient, renewable forms of energy," says Emory physical chemist Tim Lian, shown in his lab. Photo by Stephen Nowland, Emory Photo/Video.

By Carol Clark

The U.S. Department of Defense awarded $7.5 million to Tianquan (Tim) Lian, professor of physical chemistry at Emory University, to lead an investigation of electrochemical processes underlying fuel-cell technology. The award comes through the DoD’s highly competitive Multidisciplinary University Research Initiative, or MURI. The program funds teams of investigators from more than one discipline to accelerate the research process.

“A deeper understanding of electrochemical processes is important in the quest for more efficient, renewable forms of energy,” Lian says. His lab develops sum-frequency generation spectroscopy to selectively probe reactions on the surface of an electrode. The technique can provide insights into the fundamental steps involved in energy generation, conversion and storage technologies — ranging from solar cells, to fuel cells and batteries.

Fuel cell electric vehicles use a fuel cell instead of a battery — or in combination with a battery — to generate electricity for power. While they have lower emissions and higher fuel-efficiency than internal-combustion engines, fuel cell vehicles are currently limited to lighter fuels, such as hydrogen.

The Air Force Office of Scientific Research accepted the MURI proposal from Lian, principal investigator of the project, and his colleagues from five other universities, including Yale, Cornell, Massachusetts Institute of Technology, the University of Pennsylvania and the University of Southern California. Together, the researchers encompass the disciplines of advanced spectroscopy, electrochemical mass spectroscopy and electrochemical theory to model, test and interpret reactions.

“Bringing together experimentalists and theorists with different backgrounds gives us the expertise to tackle more challenging problems,” Lian says.

The concept of fuel cells was first demonstrated in 1801, while the invention of the first working fuel cell occurred in 1842, when William Grove showed that an electrochemical reaction between hydrogen and oxygen could produce an electric current. NASA later developed fuel cell applications for the space program.

“Electrochemistry goes way back in science, and has many important applications, but our understanding of it remains largely empirical,” Lian says. “The Air Force wants to make a concerted effort to advance the field by boosting our understanding of electrochemical processes at the molecular and atomic level.”

The research team will develop software for electrochemical platforms as an experimental tool to gather data at the microscopic scale of processes such as the current-voltage curve generated in an electrochemical cell. The team will also develop theoretical tools to interpret the data. They will apply these experimental and theoretical tools to study fuel-cell technologies that use methanol and ethanol directly as fuels. These fuels are more energy dense than hydrogen, giving them the potential to greatly improve the range of fuel-cell vehicles, although their use in fuel-cell technology currently suffers from poorly understood side reactions that occur on electrode surfaces.

The software and theoretical tools that Lian’s team develops will be open source, allowing researchers in other labs to use it to simulate their own electrochemical experiments as well as interpret their data.

Providing these tools to the broader electrochemical industry will support widespread efforts for innovation and discovery, Lian says. “We hope to make a lasting impact in the field, opening doors to do things with electrochemistry that are currently out of reach.”

Over the past 30 years, DoD’s MURI program has brought significant new capabilities to U.S. military forces and opened up new lines of research. Notable examples include foundations in the fabrication of nanoscale and microscale structures by the processes of self-assembled materials and microcontact printing, the integration of vision algorithms with sensors to create low-power, low-latency, compact adaptive vision systems, and advances in fully optical data control and switching.

Chemists find new way to do light-driven reactions