Tuesday, January 27, 2015

Study finds babies do learn from videos


By Megan McRainey

Children under two years old can learn certain communication skills from a video, such as how to use signs in sign language, and perform similarly in tests when compared to babies taught by their parents, according to a new paper in the journal Child Development.

Led by researchers at Emory, the study is the first to isolate the effects of purportedly educational commercial videos on infant learning. The results contradict previous research, which showed little evidence of learning from video in children under the age of two, or less robust learning than more traditional forms of parent instruction.

Emory’s study found that babies were consistently able to understand the signs and pick out a photo of the corresponding object after watching an instructional video for 15 minutes, four times a week for three weeks. Babies who watched the video performed just as well in tests as babies who had been taught signs by their parents under similar conditions (15 minutes of instruction, four times per week for three weeks) but without a video.

After a week without instruction, babies in all experimental groups were still able to produce the signs — a much more difficult task than simply recognizing them. However, babies in parent-supported groups were able to produce a greater number of signs overall.

Read more about the study here.

Related:
Uncovering secrets of sound symbolism
What is your baby thinking?

Thursday, January 15, 2015

Global bonds boost chemists' pace of research and discovery

"It's a great feeling of accomplishment," says Emory graduate student Katie Chepiga, who helped develop new methods for organic synthesis published by the Journal of the American Chemical Society. (Photo by Kay Hinton, Emory Photo/Video.)

By Carol Clark

A pair of chemistry graduate students, from Emory and Nagoya University in Japan, combined forces to demonstrate how a newer, more efficient strategy can be applied to synthesize natural compounds that hold potential medicinal benefits.

The Journal of the American Chemical Society (JACS) published their findings, showing how C-H functionalization speeds up synthesis of two promising marine alkaloids from a sea sponge, known as dictyodendrin A and F.

“We were able to cut the number of steps needed to synthesize these products nearly in half, compared to previous, more traditional methods,” says Kathryn (Katie) Chepiga, an Emory PhD student of organic chemistry. “The ability to more efficiently synthesize them greatly improves the chances that they will be produced on a larger scale so that more can be learned about their biological properties and potential benefits.”

Previous research has found that dictyodendrin A inhibits telomerase, suggesting its potential for cancer chemotherapy. And dictyodendrin F inhibits an amyloid-cleaving enzyme, hinting at its potential to treat Alzheimer’s disease.

Chepiga shares lead authorship of the JACS paper with Atsushi Yamaguchi, a graduate student from Nagoya University. Their professors and mentors are co-authors of the paper, including Huw Davies at Emory and Kenichiro Itami and Junichiro Yamaguchi from Nagoya.

Both graduate students spent time working on the problem at one another’s universities through an exchange program of the National Science Foundation’s Center for Selective C-H Functionalization (CCHF).

Atsushi Yamaguchi at work in the Davies lab at Emory in 2013. Yamaguchi is a graduate student at Nagoya University, a member of the Institute of Transformative Bio-Molecules and a collaborator with the CCHF. (Photo by Carol Clark.)

“This paper shows the power of the global network the CCHF has developed,” says Davies, director of the center, which is based at Emory. “We hope this work serves as a model for others to emulate and to expand upon – both the new methods of doing chemical synthesis and the new ways for organic chemists to combine their expertise and collaborate, rather than compete.”

The graduate students completed the synthesis of the two products over the course of one year.

“It’s common for a total synthesis project to take four to six years,” Davies says. “It’s amazing that they achieved it in such a short time. Emory had one area of expertise needed to complete the project, and the University of Nagoya had the other area. Katie and Atsushi bridged cultures and continents and brought these two areas together.”

The project began in the fall of 2013, when Atsushi Yamaguchi traveled to Atlanta to spend three months working in the Davies lab. He brought with him an idea from the Itami lab in Nagoya – to apply C-H functionalization methods to synthesize dictyodendrins.

Traditionally, organic chemistry has focused on the division between reactive, or functional, molecular bonds and the inert, or non-functional bonds carbon-carbon (C-C) and carbon-hydrogen (C-H). The inert bonds provide a strong, stable scaffold for performing chemical synthesis on the reactive groups. 

C-H functionalization flips this model on its head: It bypasses the reactive groups and does synthesis at the inert C-H sites.

Watch a video about the Center for Selective C-H Functionalization:


The CCHF is at the forefront of this major paradigm shift in organic chemistry. It brings together scientists from leading research universities across the United States, Asia and Europe – as well as from private industry – with the aim of making organic synthesis faster, simpler and greener.

At the same time, the center is preparing students for a new era of collaborative chemistry on a global scale. Undergraduates, graduate students and post-doctoral fellows can participate in national and international exchanges, learning the techniques of other labs while bringing in new ideas of their own. 

When Atsushi Yamaguchi arrived at Emory, he hit the ground running, Davies recalls. “The culture of our lab is very different from the way they work in Japan, but Atsushi just jumped right in and embraced it. He was very focused and extremely determined to learn all that he could and to make his project work.”

Chepiga shares a similar determination, as well as the desire to gain varied experiences. She entered Emory’s graduate program in chemistry in 2010, drawn by the exchange opportunities offered by the CCHF.

The center began with a network of top research universities across the United States when it launched in 2009. Since then, it has expanded through the NSF program Science Across Virtual Institutes (SAVI) to also include organic chemistry labs and research centers in Japan, Korea, England and Germany.

“In organic chemistry, you might spend your whole PhD program just learning the techniques and expertise of one lab and one professor,” Chepiga says. “When I heard how the center was changing that concept, I wanted to be a part of it. I’m gaining a range of expertise and learning how to adapt to different lab settings. And I have a much bigger network of professors and students to bounce ideas off of when I run into a problem. It never feels like there is a dull moment in a project because we can come at it from so many different perspectives.”

Last spring, Chepiga traveled to Nagoya University for three months to help Atsushi Yamaguchi complete the synthesis project. “I loved the cultural experience and working in a new environment,” she says. “I found the members of the Itami lab to be incredibly friendly and helpful.”

The challenge facing the two graduate students was to perform controlled, sequential functionalization of four C-H bonds on a pyrrole core – a basic, organic unit common in many medicinal compounds. 

The Itami lab is specialized in C-H arylation, a process that converts a C-H bond into an elaborate structure needed for the synthesis. The Davies lab is specialized in using rhodium catalysts to directly insert a carbine fragment into C-H bonds, another critical step.

“We definitely struggled at times,” says Chepiga of the problems involved. She asked for an additional month in Japan to see the project through.

While her work at the Davies lab has focused on catalyst development and applications, the exchange project required Chepiga to learn new techniques for synthesis and for analyzing the products of small-scale reactions.

The hard work paid off when they achieved results and publication by JACS.

“It is a great feeling of accomplishment,” Chepiga says. “We’re hoping that other researchers will want to explore the potential therapeutic benefits of dictyodendrins A and F, now that the synthesis is more practical. And we also hope that our synthesis methods can be applied more broadly to many other compounds with interesting biological properties.”

Combining the expertise of different labs not only boosted the pace of discovery, it also speeded up Chepiga’s academic career. She is on track to finish her PhD program within a few months, for a total of just 4.5 years, and she has already secured a post-doctoral fellowship in Germany.

Related:
NSF chemistry center opens new era in organic synthesis
Chemists now forming global bonds

Wednesday, January 14, 2015

Yak dung burning pollutes indoor air of Tibetan households

A child sits before the family stove, fueled by yak dung, in a traditional tent in Tibet. (Photo by Qingyang Xiao.)

By Carol Clark

Tibet, the highest region on Earth and one of the most remote, is associated with vivid blue skies and the crystal clear air of the Himalayas. During the long cold season, however, the traditional nomadic people spend much of their time in snug dwellings where they cook and stay warm by burning yak dung. Their indoor air can be filled with dangerous levels of fine particulate matter, including black carbon, a new study finds.

The journal Atmospheric Environment published the research, led by Eri Saikawa, an assistant professor of in Emory's Department of Environmental Sciences and in the Department of Environmental Health at the Rollins School of Public Health.

“Indoor air pollution is a huge human health problem throughout the developing world,” Saikawa says. “In a cold region like Tibet, the impact on individuals could be even greater because they spend so much time indoors and try to keep their homes as air tight as possible.”

Globally, the World Health Organization (WHO) estimated that 4.3 million people died prematurely in 2012 due to indoor air pollution from traditional stoves, fueled by coal, wood, dung or crop waste. In comparison, WHO estimated that outdoor air pollution was linked to 3.7 million deaths that year.

Yaks are an integral part of the Tibetan way of life. (Photo by Denise Jarvis/Wikipedia.)

Tibet is situated on a plateau northeast of the Himalayas in China. For centuries, nomadic people there have herded yaks, large, long-haired relatives of cattle. Yaks work as pack animals and supply meat, milk, and fiber for fabrics. They also generate heating fuel in the form of dung.

Previous studies had looked at indoor air quality in Tibet during the summer season. Saikawa and her team wanted to investigate indoor emissions during the colder months.

In March of 2013, Qingyang Xiao, a graduate student in Rollins School of Public Health, traveled to the Tibetan region of Nam Co (which means “heavenly lake”) to gather the data. About 4,500 residents live in the region, at an altitude of 4,730 meters.

Xiao used battery powered aerosol monitors to measure indoor concentrations of fine particulate matter, or particles 2.5 micrometers in diameter or smaller, which consists mainly of black carbon and organic carbon. She recorded the measurements in six households with different living conditions and stove types. Yak dung was the main fuel for cooking and the only fuel for heating.

The results showed that the average concentrations for black carbon and fine particulate matter were nearly double those reported by some similar studies of households in areas of lower altitude and warmer climates, such as India and Mexico.

Most of the families surveyed said they were aware of the dangers of indoor air pollution. (Photo by Qingyang Xiao.)

The Tibetan homes included four traditional tents and two simple stone houses. Both the tents and the houses had only one room where all of the family members slept, ate and cooked.

Three of the families used traditional open stoves without chimneys, and three had added chimneys to their stoves. A simple house with a chimney had the lowest indoor concentrations. This household lived on tourism and used liquefied petroleum gas (LPG) for cooking.

However, a stone house with a chimney had the highest black carbon concentrations.

“That was surprising,” Saikawa says. “It shows that it is misleading to think that having a chimney will always improve the situation, unless you can be sure that the home is ventilated correctly and that you have proper air flow within a dwelling.”

Xiao also surveyed members of 23 households on energy use and awareness of indoor air pollution. The families said they spent an average of 16 hours a day indoors during the colder months of the year. 

Seventy percent of those surveyed said that they were aware of the health problems associated with indoor air pollution, and some of them did not have the economic means to purchase a chimney. (The average annual income per household is less than $900 a year, and a chimney costs around $60.)

The moisture content of the yak dung is another key factor in the emission levels, Saikawa says. After a rain or snowfall, the piles of uncovered dung are moist, leading to incomplete combustion and more emissions of fine particulate matter due to increased organic carbon by smoldering.

“It’s a complicated issue,” Saikawa says. “It’s much more than just a science problem. You have to understand how people live if you want to help find solutions to improve their lives.”

The Emory research team, including students from environmental sciences and the Rollins School of Public Health, is expanding on the small sample of households in this initial study. They are investigating indoor emissions in other areas of Tibet and plan to link these measurements to a biomarker study based on blood samples of people living in the households.

Saikawa, a specialist in atmospheric chemistry, is also studying levels of black carbon emissions in the outdoor environment generated by the burning of biomass fuels like yak dung.

Black carbon absorbs heat in the atmosphere and reduces the ability to reflect sunlight when deposited on snow and ice. Its impact is greatest at high altitudes. “Black carbon emissions from burning biofuel such as yak dung have not been quantified before in the atmosphere of the Himalayas,” Saikawa says. “We know that many Himalayan glaciers are melting rapidly, and our work suggests that more black carbon is getting deposited on them than previously thought.”

She hopes to eventually work with Georgia Tech engineer Jonathan Colton to develop gasifier cook stoves that would burn yak dung in a more efficient matter, producing fewer emissions. The stove would need to be portable, to suit the nomadic way of life, affordable for the Tibetans and simple to maintain.

“We want to use our data to make the world a better place,” Saikawa says. “The ultimate goal is to reduce pollution from biomass fuels in ways that benefit human health and reduce the climate impact.”

Related:
Creating an atmosphere for change
The growing role of nitrous oxide in climate change

Monday, January 12, 2015

Chemists show proof of concept for new method of accelerating drug discovery research

"C-H functionalization has reached the stage where it can readily be applied to the derivatization of nitrogen-containing compounds, ubiquitous in the discovery and development of new medicines," says Emory chemist Huw Davies.

By Carol Clark

Chemists have made a significant advancement to directly functionalize C-H bonds in natural products by selectively installing new carbon-carbon bonds into highly complex alkaloids and nitrogen-containing drug molecules. C-H functionalization is a much more streamlined process than traditional organic chemistry, holding the potential to greatly reduce the time and number of steps needed to create derivatives of natural products.

Nature Communications published the findings, emerging from a collaboration with Novartis Institutes for BioMedical Research and Emory University. The collaboration was fostered by the National Science Foundation’s Center for Selective C-H Functionalization (CCHF), headquartered at Emory.

“This paper is essentially a proof of concept,” says co-author Huw Davies, an organic chemist at Emory and director of the CCHF. “We’ve shown that C-H functionalization has reached the stage where it can readily be applied to derivatization of nitrogen-containing compounds, ubiquitous in the discovery and development of new medicines.”

Co-authors are Novartis chemists Rohan Beckwith, Jing He and Lawrence Hamann. The CCHF is at the forefront of a major paradigm shift in organic chemistry.

The center brings together scientists from leading research universities across the United States, Asia and Europe – as well as from private industry – with the aim of making organic synthesis faster, simpler and greener.

Traditionally, organic chemistry has focused on the division between reactive, or functional, molecular bonds and the inert, or non-functional bonds carbon-carbon (C-C) and carbon-hydrogen (C-H). The inert bonds provide a strong, stable scaffold for performing chemical synthesis on the reactive groups.

C-H functionalization flips this model on its head: It bypasses the reactive groups and does synthesis at the inert C-H sites.

“We had already demonstrated that we have a tool box of reagents and catalysts that allow us to control which sites in a molecule will undergo C-H functionalization,” Davies says. “Novartis wanted to explore whether this chemistry was robust enough to be carried out on really complex compounds like alkaloids.”

Alkaloids are a family of natural products produced by plants that have biological properties important to medicine. Morphine, codeine and opioids are examples of alkaloids.

A key part of the drug development process is creating libraries of derivatives from such natural products: Groups of chemical compounds with small molecular differences. “These small differences could determine whether a compound is toxic or carries other liabilities, or has the right mix of properties to become a safe and effective therapeutic agent,” Davies says.

The results outlined in the paper demonstrate the efficiency of rhodium catalysts to selectively install a new carbon-carbon bond into complex alkaloids in a highly controlled manner.

The research also demonstrates the ability of the CHHF to pioneer new ways of chemists working together: Breaking through the traditional boundaries of individual labs, academic institutions, countries and corporations to create a global collaboration of chemists taking different approaches to similar problems.

“Novartis sees great potential in C-H functionalization,” Davies says. “It has been an early and enthusiastic supporter of the CCFH through collaborative research of scientists at Novartis and in CCHF academic labs.”

Related:
Organic chemists now forming global bonds
NSF chemistry center opens new era in organic synthesis

Friday, January 2, 2015

Emory math ranks second in Discover Magazine's 'People's Choice' awards


The people have spoken: An Emory discovery, “Mother Lode of Mathematical Identities,” is Discover Magazine’s second most popular science story for 2014, based on readers’ votes.

Emory mathematician Ken Ono, working with Michael Griffin and Ole Warnaar, found a framework for the celebrated Rogers-Ramanujan identities and their arithmetic properties, yielding a treasure trove of algebraic numbers and formulas to access them. The editors of Discover had previously ranked the find 15th on their list of the 100 most important stories for 2014.

The editors opened up the top 16 stories to a “People’s Choice” contest, allowing people to pick their favorites through several rounds of voting. A social media campaign by the Emory community and others helped the math discovery garner second place, just behind a Harvard story about stem cell therapies.

“Michael, Ole and I were pleased just to be among the final 15,” Ono says. “All of these scientific breakthroughs were important. We were honored that so many people wanted to support math. We’re especially grateful to members of the Emory Community and the University of Chicago, my alma mater, for participating and spreading the word.”

Ono’s newest discovery, “Mathematicians prove the Umbral Moonshine Conjecture,” will be generating buzz in 2015. Ono will be presenting the proof of the conjecture, including the work of collaborators, on January 11 at the Joint Mathematics Meeting in San Antonio, the largest mathematics meeting in the world.

Related:
Mathematicians find algebraic gold
Mathematicians prove the Umbral Moonshine Conjecture