University Times

Balance research presented

Researchers from the Department of Otolaryngology presented their findings on balance at a meeting of the Association for Research in Otolaryngology.

Among their presentations were two studies funded by the National Institute on Deafness and Other Communication Disorders.

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Virtual reality helpful to balance 

Research suggests that “walking” through a virtual reality grocery store can benefit people with balance disorders who otherwise may find maneuvering through grocery store aisles a source of anxiety or dizziness.

Such a virtual store in the Department of Otolaryngology is like a life-size video game that projects 3-D, moving images of a grocery store around a real shopping cart on a custom-built treadmill. A person operating the shopping cart can control his or her own speed and direction while walking up and down 18 aisles that display realistic-looking products. “Easier” aisles display larger products, like paper towels, while the more challenging aisles contain smaller products, like tiny bottles of medicine.

Led by Sue Whitney, a physical therapist at the School of Health and Rehabilitation Sciences and a researcher at the Medical Virtual Reality Center, the study followed 11 patients with balance disorders who participated in the grocery store trial at increasing difficulty levels for six weekly sessions.

Patients went through a series of balance and mobility tests and self-reported surveys before and after participating. After six weeks, the majority of patients improved in every test taken.

This ongoing trial will compare the virtual reality treatment to traditional physical therapy.

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Balancing while listening is harder with age 

Everyday tasks that require listening and balancing simultaneously, like walking while paying close attention to a conversation, may become more difficult for people as they age past their late 70s, according to research led by Joseph Furman.

Furman is a professor in the otolaryngology and neurology departments in the School of Medicine and a professor in the Department of Physical Therapy at Pitt’s School of Health and Rehabilitation Sciences, as well as director of UPMC’s Center for Balance Disorders.

Randomized trials with three groups of healthy adults, ages 24-27, 65-71 and 76-82, compared how well they were able to accomplish listening tasks while their visual and balance systems were kept busy. Seated in swivel chairs that were either upright or at a 30-degree tilt, the volunteers performed listening exercises while motionless or spinning in darkness or in light.

The researchers found all age groups reacted more slowly in general to the listening tasks when spinning than when motionless, but it was especially true for people in the oldest group.

They also found that stimulation of the ear’s gravity-sensing organs — through the 30-degree tilt of the chair — was especially powerful in slowing down a person’s auditory reaction time and also was most pronounced for people in the oldest age group.

The National Institute on Aging also supported this research.

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Emphysema protein found

A study by School of Medicine researchers has found that blocking the activity of a structural protein called caveolin-1 stops free radical-induced aging and damage of fibroblasts, a kind of lung cell, in an animal model of emphysema.

The study appears in the Feb. 27 issue of the Journal of Biological Chemistry.

In patients with emphysema, alveoli (the lungs’ air sacs in which oxygen exchange occurs) are damaged, impairing lung function.

Senior investigator Ferruccio Galbiati, professor of pharmacology and chemical biology, said, “Our findings indicate that the free radicals or oxidants produced by smoking accelerate the aging of lung fibroblasts, which may contribute to the pathogenesis of emphysema.”

Cells cannot replicate forever, he explained. After a certain number of divisions, the cycle stops due to a cellular aging process called senescence. Oxidative stress, meaning increased production of free radicals, can induce that process prematurely.

In Galbiati’s study, normal mice began to show signs of premature aging in lung fibroblasts after six weeks of exposure to cigarette smoke and developed pulmonary emphysema after six months. But premature senescence and emphysema induced by smoke exposure were significantly prevented in mice that lacked the gene to make caveolin-1.

The research was supported by the National Institutes of Health.

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Bed sharing persists despite expert advice 

In spite of expert advice opposing the practice, many parents believe the perceived benefits of sharing their bed with their infants outweighs concerns and warnings, according to a Pitt study published in the journal Academic Pediatrics.

Research that suggests increased risk of sudden infant death syndrome and accidental suffocation has prompted the American Academy of Pediatrics to advise against bed sharing.

The Pitt study interviewed 28 caregivers of infants up to six months of age — all who “bed share” regularly — in four focus groups. In every focus group, parents reported near-miss incidents of their infants suffocating. Some parents reported they would recommend against bed sharing to others, despite the fact that they bed share themselves. Others denied that bed sharing posed any risk to their infants, describing themselves as “light sleepers” and able to wake up if their children were near harm.

Researchers found that better sleep, convenience, tradition, child safety and emotional needs were common motivations for bed sharing.

Doctors’ recommendations not to bed share did not dissuade any of the caregivers. However, parents did appreciate advice on increasing the safety of bed sharing. Such tips include using a firm mattress, avoiding extra pillows and covers and putting babies to sleep on their backs.

Senior study author Judy Chang, professor of obstetrics, gynecology and reproductive sciences, said, “These findings should give physicians a better idea of the reasons behind bed sharing, allowing them to offer more customized advice on the subject. In addition to counseling against bed sharing, physicians should include suggestions for room sharing and reducing bed-sharing risks. Room sharing may be an alternative to parents, as it allows them to watch over their infants while decreasing risks for SIDS.”

Former pediatrics professor Jennifer Chianese also was an author of the study.   

This study was funded by the Department of Pediatrics.

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Tiny transistors created

 Pitt researchers have created a platform for creating electronics at a nearly single-atom scale that could yield advanced forms of high-density memory devices, transistors and computer processors.

The work stems from a technique previously developed by the same team to fashion rewritable nanostructures at the interface between two insulating materials. The researchers demonstrate this process’s various applications in the Feb. 20 edition of Science.

Physics and astronomy professor Jeremy Levy, the paper’s senior author, said, “We’ve demonstrated that we can make important technologies that are significantly smaller than existing devices and all from the same material. To sustain the development of smaller and faster computers, we will probably need to transition away from existing materials in the coming decade. The memory bits in magnetic hard drives are about as small as they can get; silicon transistors will get increasingly difficult to miniaturize. We have created advanced storage and processing capability using the same material, presenting a totally new flexibility in building electronics.”

Levy and his team reported in Nature Materials in March 2008 that their process of swapping insulators and conductors works like a microscopic Etch A Sketch.

The idea for the process originated from a visit Levy made to the University of Augsburg in Germany where the Science paper’s co-authors, Jochen Mannhart and his student Stefan Thiel, showed Levy how the entire interface could be switched between a conducting and insulating state.

Levy thought of adapting the process to nanoscale dimensions, and his student and co-author, Cheng Cen, brought the idea to fruition. Using the sharp conducting probe of an atomic force microscope, he created wires less than 4 nanometers wide at the interface of a crystal of strontium titanate and a 1.2 nanometer thick layer of lanthanum aluminate, both of which are insulators. The conducting nanowires could then be erased with a reverse voltage or with light, rendering the interface an insulator once more.

The current publication in Science illustrates that the potential of this process extends beyond simple insulators and conductors to other uses — most notably, field-effect transistors (FETs), the building blocks of computers and electronics.

Levy and his colleagues fashioned a transistor they call a “SketchFET” with feature sizes of only two nanometers — considerably smaller than the most advanced silicon transistor, which measures 45 nanometers.

The SketchFET transistor can be erased at will and replaced with other devices such as high-density memory, wiring or chemical sensors that could rival the ultra-sensitive detectors made from carbon nanotubes.

Because the sensitive region of Levy’s proposed sensor can be the same size as a single molecule, it can be used to sense the presence or absence of a single molecule, making it ideal for chemical and biological sensing technologies, he explained.

Additionally, the scale of these components is such that fundamental properties of quantum mechanics too complex to simulate with ordinary computers can be observed. So-called quantum “tunneling” — in which electrons pass through forbidden regions — was directly observed and controlled. Such behavior also may be useful in quantum simulations of novel electronic materials, and for the construction of a quantum computer.

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The University Times Research Notes column reports on funding awarded to Pitt researchers as well as findings arising from University research.

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