Research
Highlights...
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Ames' Bakac picked chemistry over lit.
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| Number 77 |
March 26, 2001 |
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A better
Lyme disease vaccine
Spring
has finally arrived, but, unfortunately, the season often brings
an abundance of deer ticks, which spread Lyme disease. The potentially
debilitating illness is the most common vector-borne disease
in the U.S. The current vaccine for the disease is based on
OspA, an outer surface protein of the Lyme disease bacterium.
The protein's structure was deciphered at Brookhaven
National Laboratory. Recently, a Brookhaven research team
has determined the three-dimensional structure of OspC, another
key protein of the Lyme disease bacterium. This research may
lead to a second-generation vaccine that would be more effective
than the current one.
[Diane Greenberg,
631/344-2347,
greenb@bnl.gov]
Ames
investigates new superconductor
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| Magnesium
diboride wires as they appear after removal from the
tantalum tube and part of a U.S. dime for scale. |
Researchers at
the DOE's Ames
Laboratory are gaining a better understanding of the
physics operating in a remarkable new superconducting compound.
The compound, magnesium diboride, becomes superconducting
at 39 Kelvin (-389 F), nearly twice the temperature of intermetallic
superconductors currently in use. In addition to addressing
the mechanism of superconductivity in magnesium diboride,
the Ames Lab researchers have gone on to map the compound's
properties and create wire segments of the material, all
in one month's time.
[Saren
Johnston, 515/294-3474,
sarenj@ameslab.gov]
Microprobe
expands X-ray capabilities
Conventional
X-ray techniques have profoundly affected our lives. The
benefits of X-ray research include advanced materials, new
drug designs, and more accurate medical diagnostic methods.
All those benefits may increase a thousand times with the
superior resolution of the hard X-ray scanning microprobe,
developed at the Advanced Photon Source at DOE's Argonne
National Laboratory. The microprobe offers unprecedented
capabilities for imaging, which open many exciting new applications
in microelectronics and in materials, biomedical, and environmental
sciences. The microprobe provides high penetration power,
allowing studies to be performed in vacuum or in ambient
pressure, or even in an aqueous environment, with applications
to a broad range of samples and configurations.
[Catherine
Foster, 630/252-5580,
cfoster@anl.gov]
Research
to drool over
A test that quickly
determines whether a person has been exposed to harmful
chemicals would be an important medical breakthrough. Typically,
the most effective method for assessing exposure requires
analysis of blood or urine but these methods often are time
consuming and expensive. But now, DOE's Pacific
Northwest National Laboratory is developing a new monitoring
technology structured around the collection and analysis
of saliva samples. PNNL's non-invasive saliva monitoring
approach, currently undergoing bench-scale laboratory testing,
is designed to be portable, highly reliable and quick in
providing results. And it will be cost-effective for home
and workplace monitoring of trace metals and organics, and
may be applicable to a broad range of drugs and environmental
contaminants.
[Geoff
Harvey, 509/372-6083,
geoffrey.harvey@pnl.gov]
Tevatron
begins Collider Run II
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| Tevatron
(click for larger group photo) |
Batavia, Ill-Officials
at DOE's Fermi National Accelerator
Laboratory announced the March 1,
2001 start of Collider Run II at the Tevatron, the highest-energy
particle accelerator now operating in the world. Researchers
at Fermilab hope that high-energy particle collisions at
the Tevatron in Run II will yield significant, long-awaited
discoveries about the fundamental nature of matter in the
universe. World attention has focused on Fermilab's two
collider detectors at the Tevatron, CDF and DZero, as the
next possible venue for discovery of the Higgs boson, an
as-yet-unseen particle that physicists believe may determine
the property of mass.
[Mike
Perricone, 630/840-5678,
mikep@fnal.gov]
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From
classics to chemistry
Andreja
Bakac is a senior chemist at DOE's Ames
Laboratory. She grew up in Croatia and might easily have
become a professor of comparative literature were it not for
a remark made by her high school chemistry teacher.
"He
said, 'Girls belong in the kitchen, not in the lab,'" says Bakac.
"He didn't mean to offend anybody, but I took that comment as
a challenge." Although literature and languages fascinated Bakac,
she chose a different career path. "Chemistry was the very next
thing I loved, and I've never regretted that choice."
Bakac's
research focuses on fundamental chemistry, because, as she says,
"nothing happens without it." She specializes in oxidation reactions
and has successfully used visible light and oxygen to photooxidize
hydrocarbons to industrially important chemicals. However, her
current work involves thermal oxidation and using metals to
drive different chemical reactions. "Instead of using light
to activate the substrate, I'm now using transition metal complexes
to activate the oxygen," she explains. "These metals bind to
and partially reduce molecular oxygen, making it more reactive
to a variety of substrates."
Bakac
is particularly interested in the intermediates, or precursors
to desired products, resulting from her thermal oxidation experiments.
"We capture them and explore their chemistry," she says. "Then
we compare our metal-based intermediates with those derived
from organic materials in the presence of molecular oxygen.
There's a lot of similarity, but there's also much that is different
and surprising."
Bakac
explains that transition metals have a number of electronic
levels and oxidation states that generate many intermediates
not available in organic chemistry. "We've seen a lot of intermediates,
which is exciting, and we've generated some of them independently,"
she says. "Now, we're beginning to understand the mechanism
by which transition metal complexes catalyze oxidations of organic
materials with molecular oxygen."
Submitted
by DOE's Ames
Laboratory
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