Spectroscopic identification and stability of the intermediate in the OH + HONO2 reaction.
Researchers have discovered an unusual molecule that is essential
to the atmosphere's ability to break down pollutants, especially the
compounds that cause acid rain.
Fuel from Cellulose
Inexpensive, efficient, and easy: direct formation of furan-based biofuels from cellulose.
Scientists in Berlin are using a new method to resolve the structure of uncharged gold nano particles.
Giza in the Nanoworld: Gold particles were arranged on virtual desert sand. 7 gold atoms form a triangle of 6 atoms with one additional gold atom attached. The cluster of 20 atoms are piled together to form a pyramid with four equivalent corners and faces; a tetrahedron. The cluster, with one atom less, can be constructed by cutting a corner atom off the tetrahedron.
[Image: Fritz Haber Institute of the Max Planck Society]
Water refineries?
New method extracts oxygen from water with minimal energy, potentially boosting efforts to develop solar as a 24-hour energy source.
A multi-institutional team of scientists has used beamline 9.0.1 at the Advanced Light Source to perform high-resolution x-ray diffraction imaging of an aerogel for the first time, revealing its nanoscale three-dimensional bulk lattice structure down to features measured in nanometers, billionths of a meter.
Researchers find cancer-inhibiting compound under the sea
University of Florida College of Pharmacy researchers have discovered a marine compound off the coast of Key Largo that inhibits cancer cell growth in laboratory tests, a finding they hope will fuel the development of new drugs to better battle the disease.
New reasons to avoid grapefruit and other juices when taking certain drugs
Scientists and consumers have known for years that grapefruit juice can increase the absorption of certain drugs
- with the potential for turning normal doses into toxic overdoses. Now, the researcher who first identified this interaction is reporting new evidence that grapefruit and other common fruit juices, including orange and apple, can do the opposite effect by substantially decreasing the absorption of other drugs, potentially wiping out their beneficial effects.
Scientists have developed the
world's thinnest balloon that is impermeable to even the smallest
gas molecules. Above is a multi-layer graphene membrane that could
be used in various applications, including filters and sensors.
Image by Jonathan Alden
Researchers in New York are reporting development
of the world's thinnest balloon, made of a single layer of graphite
just one atom thick. This so-called graphene sealed microchamber is
impermeable to even the tiniest airborne molecules, including helium.
It has a range of applications in sensors, filters, and imaging of
materials at the atomic level, they say in a study scheduled for the
August 13 issue of ACS' Nano Letters, a monthly journal.
Paul L. McEuen and colleagues note that membranes
are fundamental components of a wide variety of physical, chemical and
biological systems, found in everything from cellular compartments to
mechanical pressure sensing. Graphene, a single layer of graphite, is
the upper limit: A chemically stable and electrically conducting
membrane just one atom thick. The researchers wanted to answer whether
such an atomic membrane would be impermeable to gas molecules and
easily incorporated into other devices.
Their data showed that graphene membranes were
impermeable to even the smallest gas molecules. These results show
that single atomic sheets can be integrated with microfabricated
structures to create a new class of atomic scale membrane-based
devices. We envision many applications for these graphene sealed
microchambers, says McEuen. These range from hyper-sensitive pressure,
light and chemical sensors to filters able to produce ultrapure
solutions.
Test to protect food chain from human form of
Mad Cow Disease
Scientists are reporting development of the first
test for instantly detecting beef that has been contaminated with
tissue from a cow's brain or spinal cord during slaughter - an advance
in protecting against possible spread of the human form of Mad Cow
Disease. The study is scheduled for the August 13 issue of ACS'
bi-weekly Journal of Agricultural and Food Chemistry.
J�rgen A. Richt and colleagues point out that
removal of brain, spinal and other central nervous tissue after
slaughter is "one of the highest priority tasks to avoid contamination
of the human food chain with bovine spongiform encephalopathy," better
known as Mad Cow Disease. "No currently available method enables the
real-time detection of possible central nervous system (CNS) tissue
contamination on carcasses during slaughter," the report states.
They describe a test based on detection of the
fluorescent pigment lipofuscin, a substance that appears in high
concentrations in the nervous tissue of cattle. The researchers found
that it was a dependable indicator for the presence of brain and
spinal tissue in bovine carcasses and meat cuts. "Small quantities of
bovine spinal cord were reliably detected in the presence of raw
bovine skeletal muscle, fat and vertebrae. The research lays the
foundation for development of a prototype device allowing real-time
monitoring of CNS tissue contamination on bovine carcasses and meat
cuts," the report says. It was done with colleagues from the National
Animal Disease Center of the USDA-Agricultural Research Service and
Iowa State University. - AD
Researchers in Switzerland and Australia are
reporting identification of proteins in human breast-milk - not
present in cow's milk - that may fight disease by helping remove
bacteria, viruses and other dangerous pathogen's from an infant's
gastrointestinal tract. Their study is scheduled for the September 5
issue of ACS' Journal of Proteome Research, a monthly publication.
Niclas Karlsson and colleagues point out that
researchers have known for years that breast milk appears to provide a
variety of health benefits, including lower rates of diarrhea, rashes,
allergies, and other medical problems in comparison to babies fed with
cow's milk. However, the biological reasons behind this association
remain unclear.
To find out, the scientists collected human and
cow's milk samples and analyzed their content of milk fat. They found
that fat particles in human milk are coated with particular variants
of two sugar-based proteins, called MUC-1 and MUC-4. Previous studies
by others have shown that these proteins can block certain receptors
in the GI tract that are the main attachment sites for E. coli,
Helicobacter pylori and other disease-causing microbes, thereby
preventing infection. By contrast, since cow's milk lacks these
protein variants, it may not offer the same disease protection, the
researchers say.
A new look at the "biobed's" role in pesticide
spills
Scientists in Sweden call for
more research on the biobed, which was developed in 1993 to
prevent pesticide spills from spray tanks.
Image by Maria Del Pilar Castillo
Scientists in Sweden are cautioning about the need
for further research as more countries embrace a popular method for
preventing pesticide spills. Their review of current scientific
knowledge on the so-called "biobed" is scheduled for the August 13
issue of ACS' bi-weekly Journal of Agricultural and Food Chemistry.
In the study, Maria Del Pilar Castillo and
colleagues point out that pesticide spills are common when farmers
transfer highly concentrated liquid preparations into spray tanks
where the pesticide is diluted with water. Even if a small, few-inch
wide puddle of this concentrate spilled under the tank, the nearby
environment could be exposed to up to one hundred thousand times the
normal pesticide dose. "The risk of contamination is obvious," says
Castillo.
To remedy the problem, Swedish scientists in 1993
developed the biobed. Built from layers of grass, clay and a
biomixture of straw, peat and soil approximately two feet deep, the
biobed functions as an absorbent sponge for leaking concentrate from
parked spray tanks.
Castillo says the effectiveness and simplicity of
biobed systems help them spread worldwide. But as biobeds are modified
to suit local conditions and needs, she cautions that it is important
to analyze their actual performance in each specific location and
evaluate the effects of changes to the biobed's composition and how
local temperature and other conditions affect performance.
Toward a drug-free Olympics: Analytical
chemistry takes center stage
In the most comprehensive drug-testing effort in
sports history, Olympic officials are taking unprecedented steps to
make sure this year's athletes compete without the use of performance
enhancing drugs. But despite improvements in drug-testing techniques,
catching athletes who cheat remains difficult, according to an article
scheduled for the August 11 issue of Chemical & Engineering News.
In a feature article in the magazine, C&EN Senior
Correspondent Marc S. Reisch points out that Olympic officials will
spend about $10 million testing athletes for performance enhancing
drugs, including round-the clock monitoring of urine and blood samples.
Many of these tests will focus on identifying human growth hormone (hGH)
and erythropoietin (EPO), two products of recombinant DNA technology
that athletes have used to boost muscle mass and increase endurance.
Although analytical instruments have become more
accurate, reliable, and capable over the years, catching cheaters
remains a virtual cat and mouse game. One challenge is the use of
custom-synthesized "designer" drugs, which are difficult to identify
and test, according to the article. But with more money and effort
going into testing, athletes are likely to think twice before using
performance enhancing drugs, the article suggests.
Scientists report findings on
ways to preserve crispiness and crunchiness of bread and other
bakery products.
Photo by Marcel Meinders
Scientists in the Netherlands report an advance
toward unraveling one of the culinary world's long-standing puzzles:
How to maintain the crispy quality of bread crust. The findings could
help prolong the coveted crunchiness of bagels, French bread, and
other bakery products, the researchers say. Their findings are
scheduled for two reports in the August 13 issue of the ACS' bi-weekly
Journal of Agricultural and Food Chemistry.
In the new study, Neleke van Nieuwenhuijzen, Marcel
Meinders, Ton van Vliet, and colleagues point out that scientists have
known for years that dry bread crust starts losing its crispness when
water migrates into the crust, resulting in a perceived loss of
freshness that turns off consumers. Details of the mechanisms involved
in this effect, however, have remained a mystery until now.
The scientists baked wheat bread under different
moisture conditions, vapor pressures, and temperatures and then
studied the water content and texture of the resulting crusts using
sensitive laboratory instruments. They found that water content and
water movement in the bread during and after baking were the key
factors that determine the crispness of crusts and its retention. By
modifying these factors, bakers can optimize bread ingredients to
produce crisper, longer-lasting crusts, the researchers say. - MTS
Perfectly proportioned legs keep water striders
striding
The amazing water strider - known for its ability
to walk on water - came within just a hair of sinking into
evolutionary oblivion. Scientists in France and the United Kingdom are
reporting that the insect's long, flexible legs have an optimal length
that keeps it afloat. Their report is scheduled for the August 19
issue of ACS' Langmuir, a bi-weekly journal.
In the new study, Dominic Vella notes that
scientists already know much about the water-repellant structure of
the water strider's legs and how it allows them to efficiently scoot
and jump on ponds and lakes. However, the insect's many adaptations to
life on water surfaces pose scientific puzzles. Solving those
mysteries may have practical applications in the design of
water-walking robots that can support the maximum possible payload,
they note.
Building on earlier work by scientists at Carnegie
Mellon University, Vella developed a mathematical model to determine
the maximum weight load that a thin, flexible cylinder - representing
a water strider's legs - can support on a liquid surface without
sinking. He found that as the length of the cylinder increases, the
maximum load at first increases but then reaches a plateau at some
critical length. After that length, the cylinder begins to bend and is
not able to support more weight. Comparing the model to measurements
on museum specimens, Vella found that the strider's legs are typically
slightly shorter than the critical length. This suggests that the
water strider's legs are just the right length: Long enough to provide
maximum weight support but not long enough to bend and hinder the
insect's movement, he says. - MTS
Turning those old electronic circuit boards into
new park benches
Scientists report development of
a process that uses recycled circuit boards to create
high-strength materials, such as park benches and fences.
Image by Wikimedia Commons
Scientists in China have developed a new recycling
method that could transform yesterday's computer into tomorrow's park
bench. Their study, which focuses on decreasing environmental
pollution through resource preservation, reuses fibers and resins of
waste printed circuit boards (PCBs) that were thought worthless to
produce a variety of high-strength materials. It is in the July 15
issue of Environmental Science & Technology.
Zhenming Xu and colleagues point out that as more
electrical and electronic equipment has become obsolete, the issue of
electronic-waste removal has intensified. PCBs account for about 3
percent by weight of all electronic waste, Xu says. Although metals
from the circuit boards, such as copper and aluminum, are recycled,
landfill disposal has been the primary method for treating their
nonmetallic materials, which have been difficult to recycle, the paper
says.
In the study, the researchers developed a process
to recycle those nonmetallic materials, which they say could be used
to produce diverse items like sewer grates, park benches and fences.
The recycled material could also be a substitute for wood and other
materials since it is almost as strong as reinforced concrete. "There
is no doubt that the technique has potential in the industry for
recycling nonmetallic materials of PCBs," Xu says. - JS
"Chiral" molecules pave the way for safer, more
effective drugs
In the drive to create safer, more effective drugs
for cancer, Parkinson's disease, and other health challenges,
researchers worldwide are stepping up efforts to produce purer
substances based on a molecule's unique symmetry or chirality,
according to an article scheduled for the August 4 issue of Chemical &
Engineering News.
In the C&EN cover story, Senior Correspondent Ann
M. Thayer points out that in the pharmaceutical world, a molecule's
right- or left-handed symmetry determines whether it does good or ill
in the body. Today, about 70 percent of new small-molecule drugs that
the Food & Drug Administration approved in 2007 contained at least one
chiral molecule as its central active component.
But creating one specific configuration of mirror
image molecules rather than a mixture remains a challenge, as these
molecules are complex and difficult for chemists to construct. But
thanks to increased cooperation between academia and industry,
chemists are identifying new catalysts and reactions to produce chiral
compounds faster, more efficiently, and with fewer environmental risks,
such as metal contaminants, the article notes. Although these
processes will likely remain unknown to the average consumer, health
and the environment will benefit in the long run, the article suggests.
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