March 19, 2002
For more information on these science news and feature
story tips, please contact the public information
officer at the end of each item at (703) 292-8070.
Editor: Josh Chamot
Contents of this News Tip:
Increasing
Photonic Efficiency: Nature Knows Best
Scientists have been trying for years to apply the
principles underlying photosynthesis to the development
of a new generation of molecular-scale photonic, or
light-dependent, devices. Now, a team of chemists
supported by the National Science Foundation (NSF)
has produced efficient molecular photonic switches
with porphyrins, synthetic compounds related to the
chlorophyll molecules produced in photosynthesis.
Using high-speed laser technology, Jonathan Lindsey
of North Carolina State University (Raleigh), Dewey
Holten of Washington University (St. Louis), and David
Bocian of the University of California (Riverside)
uncovered how light energy flows efficiently from
one end of a molecular chain of interconnected porphyrins
to the other end. They developed an electrochemical
means to rapidly interrupt the energy flow and cause
the light output to turn on and off in a few trillionths
of a second.
The chemists also found that ultra-fast electronic
communication takes place not just between adjacent
molecules in a porphyrin chain, but between molecules
far removed from one another in a phenomenon called
superexchange. They are using this knowledge to design
larger and more complex arrays of porphyrins that
will further increase the efficiency of photonic devices.
[Amber Jones]
Top of Page
Biologists
Aim to Find and Grow "Bugs" Responsible For Greenhouse
Gas Methane
They've been at it for millions of years, but little
is known about wetlands bacteria that turn organic
matter into the greenhouse gas methane. Now, for
the first time, a team of scientists funded by NSF
and affiliated with Cornell University is collecting
methane-generating bacteria (called methanogens) from
oxygen-poor wetlands, and bringing them to a lab alive.
According to Cornell microbiologist Stephen Zinder,
no one has ever cultured and grown methanogens from
acidic wetlands in a laboratory. Scientists need
to know more about the conditions where the methanogens
work, he says.
Observatory sites include McLean Bog, a few miles northeast
of Cornell's Ithaca campus. The bog formed approximately
13,000 years ago when a massive chunk of glacier from
the last ice age melted and left a kettle-hole in
the surrounding gravel. Sphagnum moss, carnivorous
pitcher plants and related species cover the surface
of the bog, but researchers in the microbial observatory
project are interested in extracting the methanogens
living beneath the bog surface.
Zinder points out that, if the researchers succeed
in duplicating the carbon-rich, anaerobic, acidic
conditions where methanogens thrive, the organisms
may have a future in bioengineering – perhaps in bioremediation
of contaminated sites or in the controlled production
of methane. [Cheryl Dybas]
Top of Page
Women, Minorities,
Persons With Disabilities; Progress in Education,
Less So in Workforce
Although women, minorities, and persons with disabilities
have made educational progress in science and engineering
fields, they continue to be underrepresented in the
science and technology workforce, according to data
gathered by the Division of Science Resources Statistics
at the National Science Foundation.
The number of women receiving bachelor’s degrees in
science and engineering equaled that of men for the
first time in 1998, according to the information gathered
by NSF. In addition, Blacks, Hispanics, and American
Indians/Alaskan Natives are now as likely as whites
to major in science and engineering at the college
level.
However, while more degrees are being awarded to underrepresented
minorities than in previous years, graduation rates
are lower than compared to whites. In addition, Blacks,
Hispanics, and American Indians/Alaskan Natives are
underrepresented in engineering and scientific professions.
Persons with disabilities represent 1 percent of the
persons earning science and engineering doctorates
in 1999 and more than 12 percent of the college-educated
population, yet only make up about 6 percent of most
science and engineering related professions.
For more information, see: http://www.nsf.gov/sbe/srs
Top of Page
|