April 19, 2002
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Editor: Josh Chamot
Contents of this News Tip:
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
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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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: http://www.sspi.org/html/index9.html
For historical background on the MARISAT, see: http://www.hughespace.com/factsheets/376/marisat/marisat.html
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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
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
For images of Neurospora, please see: http://www.fgsc.net/neurosimages/neuimage.htm
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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
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
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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