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News Tip


April 19, 2002

For more information on these science news and feature story tips, contact the public information officer listed at (703) 292-8070. Editor: Josh Chamot

New Nanomembrane Could Purify Natural Gas

Researchers supported by the National Science Foundation (NSF) have developed a polymer membrane that sorts and removes unwanted by-products in natural gas at the nanoscale, which may lead to a clean, efficient purification method. Natural gas is a widely used source of potentially clean fossil energy, commonly used for heating and cooking. However, the gas naturally contains both useful methane and unwanted hydrocarbons which can condense, causing clogged pipes and inefficient burning.

The new membrane, composed of loosely packed hydrocarbon chains, uses chemical diffusion to "weed out" large vapor molecules while retaining smaller, desirable ones. Chemical engineer Benny Freeman of the University of Texas at Austin and materials scientist Ingo Pinnau of Membrane Technology and Research, Palo Alto, California, developed the membrane from an existing polyacetylene material by introducing silicon dioxide "nanospacers" - making the material both more permeable and more selective. They report the process in the April 19 issue of Science.

The ability to sort by molecule weight, the scientists believe, could lead to the ability to remove impurities from natural gas as it flows through pipes at high pressure, allowing industry to replace the costly and energy-intensive purification process currently used. [Amber Jones]

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NSF Recognized for Innovation in Extending Satellite's Life and Link to South Pole

Due to the Earth's curvature, the NSF's Amundsen-Scott South Pole station is unable to use satellites in geostationary orbits roughly 36,000 kilometers (22,300 miles) above the equator. As a result, scientists have been unable to transfer data from experiments, operate equipment remotely or use telephones or the Internet from the station.

NSF and Comsat recently joined forces to put an aged Comsat General communications satellite to work as a link to Amundsen-Scott station. In recognition, the Society of Satellite Professionals International has given the NSF's Office of Polar Programs and Comsat General Corporation its Industry Innovator Award.

Under the leadership of Patrick D. Smith, the Antarctic Program's technology development manager, NSF and Comsat brought the MARISAT F2 satellite into service for the South Pole.

The 26-year-old satellite is in excellent condition and now gives the station six hours of daily connectivity, allowing high-quality Internet access for supporting scientific research and vital mission operations, such as telemedicine. In conjunction with a small handful of other satellites, the telecommunications window at the pole now spans half of the day.

MARISAT was launched in 1976 as an early member of the world's first global maritime satellite system. Comsat's efforts to preserve the satellite over the intervening years have allowed natural forces to tilt the satellite's orbit away from the equator and towards the poles, allowing the station to "see" it for a limited time each day. This places MARISAT in a very select and unusual family of satellites.

Karl A. Erb, who heads the U.S. Antarctic Program at NSF, said the award recognizes work that echoes the determined spirit of early Antarctic explorers to overcome geography in pursuit of scientific knowledge in remote and harsh regions.

"I commend Pat, and those on his team, for their ability to take advantage of an opportunity others might have missed," he said. "The Antarctic research community owes them a debt of thanks."

NSF manages the U.S. Antarctic Program, which coordinates almost all U.S. scientific research on the continent and its surrounding ocean. NSF maintains three year-round stations in Antarctica. [Peter West]

For more information about the non-profit SSPI's awards program, see:

For historical background on the MARISAT, see:

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Molds Provide New Insights into Gene Silencing

A study on molds raises startling new questions about gene silencing, an important factor in disease resistance. The NSF-funded research focuses on Neurospora crassa (commonly called pink bread mold), a fungus that has been a useful genetic model for more than half a century.

Molds and humans share at least one fundamental trait: in both species, the parents must donate a copy of their DNA to their offspring in order to successfully reproduce. Parental chromosomes pair up and split apart to form offspring or sex cells (sperm and eggs), in a complex cellular process called meiosis. This occurs in all organisms that reproduce sexually, from people to plants to fungi.

NSF-supported Stanford University researcher Patrick Shiu and his colleagues took a closer look at meiosis in pink bread mold and made a surprising discovery. They found that any extra copies of unpaired (and therefore probably unwanted) genes are "turned off" in a cell in the early stages of meiosis, before the parental chromosomes separate.

"In meiosis, normal chromosomes pair with one another perfectly," says Stanford scientist Robert Metzenberg, also involved in the study. "We discovered that, when mold chromosomes pair, there's a built-in checking system we didn't expect to find that determines whether the pairing is correct." According to Metzenberg, the checking system does not detect tiny differences in the two DNA sequences, but deviations the size of a gene, or larger, will trigger the mechanism.

Organisms are normally under siege by viruses and other "invaders," explains Metzenberg, "and most of them are bad. They make you carry something you shouldn't, or they may disrupt a gene you need. And they would like to hitch a ride into the future by jumping into your progeny." The checking process weeds the invading genes out.

According to Metzenberg, in this newly discovered process - dubbed MSUD, for meiotic silencing by unpaired DNA - it's as if the organism says, "no thanks, I don't want that. I'm going to activate my cellular machinery to turn off genes that are not paired properly. This is a defense system that guards the mold against invasion at a time when its chromosomes are especially vulnerable." The scientists suspect that there is a similar process in humans, but have not yet found the mechanism. [Cheryl Dybas]

For images of Neurospora, please see:

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Media, Anger Figure in Terrorism Response

Policy makers and scientists worldwide are using information on the psychological impact of the events of September 11 to confront the potential psychological and social consequences of chemical and biological terrorism.

At a recent meeting at NATO headquarters in Brussels, Jennifer Lerner, assistant professor of decision science and psychology at Carnegie Mellon University, presented results of an NSF-supported experiment examining people's emotional responses to news of terrorism. Doctoral students Roxana Gonzalez and Deborah Small, and Baruch Fischhoff, professor of social and decision sciences, also worked on the study. The study will be published in an upcoming issue of the journal Psychological Science.

The study, supported by both NSF and the American Psychological Association, was based on a field experiment with a nationally representative sample. Researchers gathered responses nine days after the attacks and again eight weeks later. For the second response data set, they presented different news stories (all from major media outlets) to different people in order to determine the effects of the stories on people's emotions and perceptions.

The study found that people's emotional responses to the events were strongly influenced by media portrayals of the events. It also found that Americans who experienced anger in response to the coverage were more optimistic about the future, less likely to take precautionary actions, and more likely to favor aggressive responses than those who experienced fear. In addition, more men than women experienced anger, which led to greater optimism among men than women.

Finally, although individuals on average saw themselves as less vulnerable to risk than "the average American," most respondents perceived considerably high levels of personal risk. [Bill Harms]

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