ScienceCache

Vol. 216
Jan. 13, 2006

FLU NOT THE ONLY GERM THREAT THAT’S BUGGING YOU
The flu hasn’t even hit hard yet this year, but it seems like everyone’s getting sick. What’s the deal? Simply put, there are a lot more infectious invaders besides the flu to worry about. They don’t get the big headlines, but they still knock people down for days or weeks and cause thousands of deaths each winter. Metapneumovirus. Rhinoviruses. Coronaviruses. Parainfluenza. Respiratory syncytial virus (RSV). Pronouncing the names of the microbes can be almost as difficult as bearing the illnesses themselves. They’re on doorknobs, faucets, and appliance handles all around you, and maybe in your nose and lungs too. Some of the viruses are also wafting through the air you breathe, looking to land in your eyes or nose and set up house inside your body. And those are just the respiratory germs – never mind Strep in the throat and ears, or Norwalk viral agents that attack the GI system, and so on. Infectious disease experts Ann Falsey and Ed Walsh have tracked the dangers from one of the most common bugs, RSV, and they say the threat to some groups of people, such as the elderly, equals that from flu. Even though flu gets all the press, RSV is a stealth bug worthy of attention too. “A lot of cases that people think are from flu aren’t really the flu at all, but other respiratory viruses like RSV. RSV is responsible for a lot of the illness blamed on flu,” says Falsey. “At least with the flu, we have something to control it – a vaccine. We don’t even have that for RSV.” She and Walsh have identified several proteins on the surface of RSV, an important step toward creating a vaccine, but none of the vaccines they’ve tested thus far has panned out.
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BLOOD FLOW IN BRAIN TAKES A TWIST, AFFECTING VIEWS OF ALZHEIMER’S
New findings that long-overlooked brain cells play an important role in regulating blood flow in the brain call into question one of the basic assumptions underlying today’s most sophisticated brain imaging techniques and could open a new frontier when it comes to understanding Alzheimer’s disease. In a paper to appear in the February issue of Nature Neuroscience and now available on-line, scientists demonstrate that star-shaped brain cells known as astrocytes play a direct role in controlling blood flow in the brain, a crucial process that allows parts of the brain to burst into activity when needed. The finding is intriguing for a disease like Alzheimer’s, which has long been considered a disease of brain cells known as neurons, and certainly not astrocytes. “For many years, astrocytes have been considered mainly as housekeeping cells that help nourish and maintain a healthy environment for neurons. But it’s turning out that astrocytes may play a central role in many human diseases,” said neuroscientist Maiken Nedergaard, who has produced a string of publications fingering astrocytes in diseases like epilepsy and spinal cord injury. “In a disease like Alzheimer’s, for instance, perhaps it’s the astrocytes themselves that are damaged first. It may be that for whatever reason, astrocytes are not doing their job properly, and then blood flow decreases. This could lead to the death of the neurons, which would starve from a lack of nutrients, since the neurons depend on the astrocytes for their survival.”
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WATER BOILS, AND COMPUTERS CAN FINALLY KEEP UP;
COFFEE DRINKERS BENEFIT
Everyone knows what happens to water when it boils – everyone, that is, except computers. Modeling the transformation process of matter moving from one phase to another, such as from liquid to gas, has been all but impossible near the critical point. This is due to the increasingly complex way molecules behave as they approach the change from one phase to another. Now researchers in the departments of physics and chemical engineering have created a mathematical model that will allow scientists to simulate and understand phase changes, which could have an impact on everything from decaffeinating coffee to improving fuel cell efficiency in automobiles of the future. The findings have been published in Physical Review Letters. "This problem has baffled scientists for decades," says Yonathan Shapir, professor of physics and chemical engineering and co-author of the paper. "This is the first time a computer program could simulate a phase transition because the computers would always bog down at what's known as the 'critical slowdown.' We figured out a way to perform a kind of end-run around that critical point slowdown, and the results allow us to calculate certain critical point properties for the first time." Shapir worked with chemical engineering Professor Eldred Chimowitz and physics graduate student Subhranil De to solve the problem. The team's simulation approach could be used by industry in a variety of ways, including deriving more power from a fuel cell. Since fuel cells rely on the transportation of protons through a membrane separating two electrodes, Shapir and Chimowitz believe it should be possible to use their work to find the most efficient configurations for a fuel cell. Other applications, such as removing the caffeine from coffee, work in a similar way and will likely also benefit.
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