Category: Health & Medicine

Psychological discomfort discourages eating disorders

Post author By Margaret Allen
Post date November 1, 2008

Popular culture’s image of the 21st-century woman is tall, large-breasted, narrow-hipped and ultra-slender. Like cultural standards of beauty throughout history, today’s “thin ideal” is unattainable for most women; for many, it also can be destructive.

Katherine Presnell, assistant professor of psychology, is helping at-risk teens challenge this ideal with the Body Project, an eating disorder prevention program that she helped develop with psychology professor Eric Stice at the University of Texas at Austin, where she earned her doctorate in 2005.

Since Stice conducted the first trial in 1998, more than 1,000 high school and college women, including 62 SMU students, have completed the program, including a research trial led by SMU Ph.D. students.

Independent studies conducted at universities nationwide and a recent analysis have shown that the Body Project significantly outperforms other interventions in promoting body acceptance, discouraging unhealthy dieting, reducing the risk of obesity and preventing eating disorders. And these results have persisted for three years.

Prevention is critical because about 10 percent of late-adolescent and adult female Americans experience eating disorder symptoms.

Katherine Presnell

Less than a third seek treatment, and less than half of those experience lasting results, says Presnell, director of SMU’s Weight and Eating Disorders Research Program in the Department of Psychology in SMU’s Dedman College.

While traditional interventions focus on education about anorexia, bulimia and binge eating, the Body Project is based on cognitive dissonance, which is the 1957 theory that inconsistent beliefs and behaviors create a psychological discomfort that motivates individuals to change their beliefs or behaviors.

While working with a patient who had anorexia during his postdoctoral studies at Stanford University, UT’s Stice says he asked her “to talk me out of being anorexic, and it was a very powerful exercise. Arguing against her own arguments caused her to rethink her perspective on her illness.”

Pictured right: Eric Stice

Body Project participants, recruited through fliers and mailings, argue and act against the thin ideal during four small-group sessions with a trained leader. They write letters to hypothetical girls about its emotional and physical costs, and challenge negative “fat talk” while affirming strong, healthy bodies.

“Many girls don’t question the messages we get from the media, the fashion industry, our peers and parents that it’s important to achieve the thin ideal at any cost,” Presnell says. “We have the girls critically evaluate the ideal, and that creates the dissonance they work to resolve.”

The Body Project includes a four-session weight management intervention that helps participants make small lifestyle changes to gain control over eating, such as scheduling time for daily exercise and a nutritious breakfast, and rewarding themselves with a book or bath rather than food.

“These little tweaks help participants maintain a healthy body weight and ward off unhealthy behaviors such as extreme dieting, fasting and self-induced vomiting to lose weight,” Presnell says. — Sarah Hanan

Tags Dedman College, Eric Stice, Katherine Presnell, SMU Department of Psychology

Culture, Society & Family Health & Medicine

Tribe, urban poor supply insight into diabetes

Post author By Margaret Allen
Post date October 24, 2008

Shawna, who is pregnant, calls diabetes a scourge. She is a member of the Akimel O’odham tribe in Arizona. “Diabetes is a sign that this life we’re living isn’t our life,” she says. “The one our ancestors had was way better.”

Before World War II, diabetes was rare among the members of the Akimel O’odhams, also known as the Pima. Today, however, Shawna is among the 12,000 tribal members on the Gila River Reservation in south central Arizona who have the highest recorded rate of diabetes of any population in the world.

The decline of agriculture set the stage for the health crisis, says Carolyn Smith-Morris, assistant professor of anthropology in SMU’s Dedman College and author of the new book “Diabetes Among the Pima: Stories of Survival” (University of Arizona Press, 2006), the first ethno-graphic account of diabetes in a community. The dramatic change of diet and reduction in activity levels, as well as a genetic predisposition to the disease, led to the epidemic, which affects 50 percent of the adults on the reservation, says Smith-Morris.

“This epidemic is about a culture defining its path in an industrial world,” she says.

For more than 30 years, the National Institutes of Health and other government and private agencies have studied the disease in the isolated Akimel O’odham population. Much of what doctors know about diabetes, a chronic disease that develops when the pancreas stops producing insulin, is based on research with the Akimel O’odhams.

Beginning in 1996, Smith-Morris lived and worked part time on the Gila River Reservation, attending health care classes, visiting medical clinics and joining holiday parades, birthday parties and bingo nights.

“After two and half years, I was finally invited to my first family memorial, spent my first nights in Pima homes, and began in earnest to study life at Gila River,” she says.

As a medical anthropologist, she has helped health care workers at Gila River better understand the Akimel O’odham culture and its attitudes about diabetes. She has spent 10 years studying the causes and conditions of the epidemic. Smith-Morris found that diabetes care practices that work in other cultures have not been as successful with the Akimel O’odhams.

From information gathered through personal interviews, surveys and observation, Smith-Morris’ research suggests that the Akimel O’odham’s diabetes epidemic can be curbed through a community-based approach tailored to their culture.

More than 95 percent of the population is obese, a risk factor of diabetes, but promoting jogging hasn’t worked well in a desert with few paved roads, Smith-Morris says. And a health care system based at one hospital is not always effective on a 372,000-acre reservation, where most residents live in poverty and where many residents don’t have cars. Buses run regularly to carry people to medical appointments, but the Akimel O’odham culture does not live by the clock, she says. In fact, while living among the Akimel O’odham, Smith-Morris deliberately slowed her big-city gait to match their more leisurely pace. In addition, diet change is expensive for a population where most live in poverty.

Based in part on her research, the tribe has spent millions of dollars to develop community-based clinics staffed by field nurses and case managers who provide more home-based care.

Smith-Morris’ research also suggests that improving prenatal care for Akimel O’odham women like Shawna can help curb the diabetes epidemic. Nearly 12 percent of pregnant women on the Gila River Reservation are diagnosed with gestational diabetes, compared with the U.S. average of 4 percent. Women with gestational diabetes and their babies are more likely to develop Type 2 diabetes and its complications of kidney failure, blindness and amputations later in life.

“The Pima want to avoid diabetes,” Smith-Morris says. “They want to learn, but not always through the traditional Western methods of written materials and lectures. This epidemic is about a culture defining its path in an industrial world.”

Smith-Morris’ current research focuses on diabetes prevention in the urban setting of South Dallas, where 33 percent of families live in poverty and 61 percent are unemployed. She developed the diabetes prevention component of a proposed $15 million project to create a wellness center in a South Dallas neighborhood. The Baylor Office of Health Equity and the Foundation for Community Empowerment are developing plans for the community-based program.

“My advocacy in these projects has impressed upon investors and planners that healthier lives need less clinic-based, biomedical intervention and more infrastructure support such as family-friendly neighborhoods and jobs that pay a living wage,” she says.

She sees positive signs of change as tribal officials are taking more control of their health care system and health education. The hospital has hired more field nurses who travel to patients’ homes. Pima women are encouraged to fry their traditional bread in oil instead of lard.

Non-Native American health care workers also have a new opportunity to better understand their patients’ culture. Bill Knowler, head of the NIH diabetes, digestive and kidney disorders research office in Phoenix now requires all Gila River Reservation NIH workers to read Smith-Morris’ new book. &#8212 Nancy Lowell George

Tags Carolyn Smith-Morris, Dedman College, SMU Department of Anthropology

Health & Medicine Plants & Animals

Pound-for-pound, chihuahuas and children expend more energy

Post author By Margaret Allen
Post date October 10, 2008

If you’ve ever visited a dog park, you may have noticed that a chihuahua tires much more quickly than a German shepherd. That does not occur just because a small dog takes more steps to cover the same amount of ground, says Peter Weyand, associate professor of applied physiology and biomechanics in SMU’s Annette Caldwell Simmons School of Education and Human Development.

In his research into animal and human physiology, Weyand has studied the impact of such factors as muscular force and the amount of time limbs are in contact with the ground on the energy cost of walking and running.

His years of research on creatures ranging from goats to antelopes to kangaroos indicate that smaller animals expend much more energy per pound to locomote. For example, a mouse expends 30 times more energy than an elephant in proportion to their weights, while human children use about twice as much energy as their parents to cover the same distance, he says.

Weyand and colleagues have found that one of the essential determinants of energy expenditure, fatigue rates and performance is the amount of time muscles are active to apply force to the ground, bicycle pedals or other external objects.

“This holds true whether you are a chihuahua, a German shepherd, Usain Bolt or a couch potato,” he says. Shorter times mean higher rates of energy expenditure and more rapid fatigue, but they are also necessary for high-end performance.

Now the holder of a patent on his methods, Weyand has explained the limits of human and animal running performance for the History Channel, CNN, the Canadian Broadcasting Corporation, NHK Television Japan and a host of other media outlets. He monitored sprinter Michael Johnson’s running mechanics in a special feature for NBCOlympics.com during the 2000 Athens games and has provided live commentary for the Boston Marathon.

Weyand’s research is funded in part by the U.S. Army Medical Research and Materiel Command, which hopes to develop quick methods to assess and monitor soldiers’ physical fitness to help improve their overall healthcare. He’s also helping to develop a new SMU undergraduate major in applied physiology and sports management.

Tags Annette Caldwell Simmons School of Education & Human Development, Peter Weyand

Health & Medicine Mind & Brain

Deep breathing worsens panic-attack symptoms

Post author By Margaret Allen
Post date September 15, 2008

Southern Methodist University psychology professor Alicia Meuret proves conventional wisdom is dead wrong: A person suffering a panic attack who tries deep breathing to calm themselves only increases his or her level of hyperventilation and overall panic-related symptoms.

Meuret’s solution? Self-training to expel lesser amounts of carbon dioxide using a hand-held, biofeedback device results in the ability to normalize breathing and avoid hyperventilation.

Tags Alicia E. Meuret, Dedman College, SMU Department of Psychology

Energy & Matter Health & Medicine Student researchers Technology

Skeptics aside, “computing with light” will replace silicon chip

Post author By Margaret Allen
Post date June 30, 2008

Gary Evans

SMU Professor of Electrical Engineering Gary Evans recently received some good news: Journal reviewers said they thought his proposal for solving one of the most perplexing problems in the emerging field of integrated photonics sounded impossible.

“To me, that’s extremely promising when the reviewers don’t think it’s possible,” Evans said. “When that’s happened, it’s been fun showing the reviewers that the conventional wisdom is incorrect.”

Photonics is the science of processing or transmitting information using light. Fiber-optic systems — perhaps the field’s best known application — transform telephone conversations into laser-generated signals that travel through thin glass wires to machines that decode the signals at the other end.

A photon is a light quantum, the smallest measurable unit of light. Integrated photonics researchers seek to create circuits that use photons to do what electrons do in electric integrated semiconductor circuits.

Evans and Jerome Butler, university distinguished professor of electrical engineering, think they have hit on a solution to the problem of integrating an optical isolator with other components in a photonic circuit. In electric semiconductor circuits, diodes act as isolators by letting electrons flow in only one direction.

“Isolation is crucial when you put about 1 billion devices on a single chip of silicon,” Evans says. The two researchers want to integrate an optical isolator with a tiny semiconductor laser that would let light travel in one direction within a photonic semiconductor circuit and keep it from reflecting back into the laser, where it could create instabilities in the laser’s output.

It is understandable that their peers might be skeptical, Evans says. Researchers around the world have been trying to create integrated photonic isolators since the 1970s and no one has overcome the problem of reflection in photonic circuits.

Evans had a similar experience when he worked with lasers at RCA Labs in Princeton, N.J., before joining SMU. In 1984 all semiconductor lasers were edge-emitting, meaning they generated light from the edge of the chip rather than the surface. Evans and his team proposed a surface-emitting laser to the U.S. Air Force.

“Their reviewers said we could never get light out, much less create a laser,” he recalls, adding that his team wrote a proposal and nevertheless received funding from the Air Force starting in 1985.

In only seven years, Evans’ group got light out of the system and demonstrated surface-emitting lasers with performance efficiencies as good as edge-emitting lasers. When he came to SMU in 1992, the Air Force continued to fund Evans’ work, which resulted in a spin-off company, Photodigm in Richardson, Texas.

Photodigm conducts research for the government and manufactures a range of lasers, most of them edge-emitting lasers that have been improved using processes developed for surface-emitting ones, says Evans. He is Photodigm’s co-founder, vice president and chief technology officer. Another co-founder is Jay Kirk, the Electrical Engineering Department’s lab manager and Evan’s former colleague at RCA. Electrical Engineering Chair and Associate Professor Marc P. Christensen is on the company’s technical advisory board, as is Butler, who worked closely with Evans when he was at RCA and helped lure him to SMU.

Evans has since expanded into medical photonics, working with SMU and Drexel University colleagues on a photodynamic therapy system to treat cancer of the esophagus.

Marc Christensen

Similar laser-based systems are used commercially, but they are large and water-cooled. The team hopes to create a machine that’s portable and cheap enough for use in every doctor’s office. Their design uses arrays of semiconductor lasers, each no bigger than a grain of sand, inserted into the esophagus via a balloon catheter. The patient is given a photosensitive drug that kills cancer cells during a chemical reaction triggered by the lasers.

Christensen says SMU’s photonics researchers — who include faculty members in electrical engineering, mathematics and physics, plus their graduate students — come together periodically for interdisciplinary meetings because so many fields are involved in creating and understanding photonic devices.

Christensen’s Photonic Architectures Laboratory has received more than $2 million in grants from the Defense Advanced Research Projects Agency, DARPA, for a project to make unmanned aerial vehicles, UAVs, stealthier.

“Today we think of a Predator UAV as flying at 30,000 feet carrying a really nice camera with a long lens that can zoom into an area on the ground and look at it very carefully,” Christensen says. Ideally, the device would be tiny with a flat lens, like a cell phone camera; however, those cameras do not produce images of adequate resolution.

Christensen’s interdisciplinary team has devised a multi-step solution that starts with an array of hundreds of tiny, flat, square cameras and equally tiny, square mirrors placed in a grid pattern that can be mounted on the underside of an aircraft as small as a model airplane. Each camera will provide slightly different information about the subject because each takes a photograph from a slightly different angle.

Computational imaging is then used to combine the numerous low-resolution images to create a sharper image that is akin to one taken by a high-performance camera too heavy to fit on the small aircraft.

Computational imaging: Each hexagonal
face is a micro-mirror, individually
positioned to create an overall shape.

“Wouldn’t it be great if the camera could determine from its wide shot which objects in the field are most important and be able to zero in on them?” Christensen asks.

Such a camera is under development at SMU. Called an adaptive resolution camera, it would analyze the wide view and use mathematical formulas to identify objects of interest — such as aircraft on the ground.

Instead of simple mirrors, the adaptive resolution camera uses an array of micro-electric machines, called MEMs. Each MEM looks like a mirror that is hundreds of microns across, or about the width of a few human hairs, attached to three even smaller levers. The levers would reposition the mirrors in the desired direction to improve the information collected by the camera’s next photographs to create another, better image — all faster than the blink of an eye.

The smarter camera would automatically put more pixels in the areas of interest and less in those considered unimportant, he says, adding that the resulting picture may look strange by conventional standards, but it would provide more useful information.

The team from the Department of Electrical Engineering in the SMU Bobby B. Lyle School of Engineering incorporates skills from physics, mathematics and computer science. Assistant Professor Dinesh Rajan, a specialist in information theory, finds the mathematical route to the best final image, a so-called “goodness value.” Associate Professor Scott Douglas, an adaptive algorithms expert, crafts the formulas to make the system home in on the important details within the big picture. And Professor Panos Papamichalis works on their robustness, making the system more tolerant of the adversities the camera will encounter in daily use.

Integrated circuits make the thousands of necessary computations, and “given the need for miniaturization, the best way to reduce the size of those circuits would make them fully photonic,” Christensen says. That step, however, is some time off. For semiconductor laser structures, Christensen works with Evans.

The two have just started a project, also for DARPA, in collaboration with the University of Texas at Dallas, Photodigm, Raytheon and Northrop Grumman. The goal: to develop signal processing with photons, instead of electrons; in other words, computing with light.

To achieve this they must create the photonic equivalent of a semiconductor chip. Most computer chips are made with silicon, which doesn’t emit light very well. A better choice is indium (In) phosphide (P), called a III-V semiconductor, Christensen says. The goal is to emit and control light, one photon at a time.

“At the quantum level you are literally controlling individual photons and providing gain (to amplify signals),” says Christensen. He compares the current state of photonic integrated circuits with the world’s first electronic integrated circuit, invented at Texas Instruments 50 years ago this summer by the late Jack Kilby when he linked a handful of transistors on a single silicon chip. Over the next 50 years, semiconductors evolved from a handful of components on that first chip to hundreds of millions of components on a single chip, he says.

“If you look at the state of photonics processing, it’s about 6 to 15 components,” he says. “It’s like we’re starting today where Jack Kilby was 50 years ago, and it will be interesting to see where a few decades takes the field of integrated photonics.” — Deborah Wormser

Tags Dinesh Rajan, Gary Evans, Jay Kirk, Jerome Butler, Lyle School of Engineering, Marc Christensen, Panos Papamichalis, Scott Douglas