It?s all in the wiring: biocomponents at the heart of an artificial photosystem.
Image:
Electrons released by irradiation of PSI and transmitted along the wire are very efficiently transmitted to the gold electrode by the viologen group.
[Image credit: Wiley]
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Physics - Fundamental
Research
New technique boosts protein NMR imaging speeds
A researcher believes he has found a quicker and more efficient approach to using SSNMR called paramagnetic relaxation-assisted condensed data collection, or PACC.
The researchers bring together theoretical models and experimental data to explain protein folding.
Image: The UCSD model of the folding energy landscape for cytochrome c. The landscape was probed experimentally at Caltech, using time-resolved fluorescence energy transfer from six donor labels (represented as single spheres of differing colors) to the heme acceptor.
A simple, chemical materials model may lead to a better understanding of the structure and organization of the cell according to a Penn State researcher.
Image:
Primitive artificial cell created with lipid membrane and two large molecules.
Construction of a selective uranium-binding protein.
Image: This NikR mutant only binds
to DNA in the presence of uranyl, not in the presence of
nickel or other metal ions.
[Image credit: Wiley]
How cells handle broken chromosomes
Scientists from the Max Planck Institute of Biochemistry discovered a novel cellular response towards persistent DNA damage.
Aldehyde tags put chemical modifications where they?re needed.
Image:
DNA for the core sequence of six amino acids ? leucine, cysteine, threonine, proline, serine, and arginine (red letters) ? is cloned into the gene for the recombinant protein at the locus to be chemically modified.
Houseplant pest gives clue to potential new anthrax treatment
Researchers at the University of Warwick have found how a citric acid-based Achilles heel used by a pathogen that attacks the popular African Violet house plant could be exploited not just to save African Violets but also to provide a potentially effective treatment for Anthrax.
Even natural perfumes may cause allergies
Hypersensitivity to perfumes is the most common contact allergy in adults. Research at the University of Gothenburg, Sweden has demonstrated that even natural aromatic oils, which many deem harmless compared to synthetic perfumes, may cause allergic reactions.
New imaging technique reveals the atomic structure of nanocrystals
A new imaging technique developed by researchers at the University of Illinois overcomes the limit of diffraction and can reveal the atomic structure of a single nanocrystal with a resolution of less than one angstrom (less than one hundred-millionth of a centimeter).
By manipulating the magnetization of a liquid solution, the researchers have for the first time coaxed magnetic and non-magnetic materials to form intricate nano-structures
Egg-irony: High cholesterol food may reduce
blood pressure
Eggs might reduce high blood pressure,
scientists report.
Image credit: Wikipedia
Researchers in Canada are reporting evidence that
eggs - often frowned upon for their high cholesterol content - may
reduce another heart disease risk factor - high blood pressure.
They describe identification of egg proteins that
act like a popular group of prescription medications in lowering blood
pressure. The report appeared in the Feb. 11 issue of ACS' Journal of
Agricultural and Food Chemistry, a bi-weekly publication.
In the new study, Jianping Wu and Kaustav Majumder
note that eggs are an inexpensive source of high-quality protein and
other nutrients. Egg consumption, however, has decreased during the
last 40 years amid concerns about cholesterol. Recent studies do
suggest that healthy people can eat eggs without increasing their
heart disease risk. Other research hinted that certain egg proteins
might have effects similar to ACE inhibitors, prescription drugs used
to treat high blood pressure.
Pursuing that lead in laboratory studies, the
scientists identified several different peptides in boiled and fried
eggs that act as potent ACE inhibitors. The scientists showed that
enzymes in the stomach and small intestine produce these peptides from
eggs. Fried eggs had the highest ACE inhibitory activity. It will take
studies in humans to determine if the egg proteins do lower blood
pressure in people, the scientists emphasized. Funding for the
research came from livestock and poultry industry groups. - MTS
In an effort to curb the illegal use of steroids in
the European beef industry, scientists in the United Kingdom are
reporting the development of a new test that can identify steroids
with higher accuracy, more convenience, and less cost than
conventional doping tests. Their report is in the current issue of
Analytical Chemistry, a semi-monthly journal.
In the new study, Rodat Cunningham and colleagues
note that the European Union banned use of growth-promoting agents in
cattle. However, widespread abuse of steroids continues and remains
difficult to detect, they say. The standard methods for detecting
steroid abuse - mass spectrometry and gas chromatography - involve
directly measuring these substances in cattle. But the tests are
expensive and can't detect some of the newer steroid hormones.
The scientists describe a new test that measures
steroids indirectly based on chemical changes associated with growth
and muscle development in steroid-treated cattle. Using a commercial
blood analyzer commonly found in hospitals, the researchers measured
20 chemical markers, including proteins and cholesterol, in cattle
treated with and without commonly used steroids over a 42-day study
period. The new test detected the steroids with accuracy between 91
and 96 percent. The study opens the door to on-site steroid testing
with portable instrumentation, the researchers say. - MTS
Injections of licorice ingredient show promise
as treatment for cocaine addiction
An ingredient in licorice shows promise as an
antidote for the toxic effects of cocaine abuse.
Image credit: American Chemical Society
An ingredient in licorice shows promise as an
antidote for the toxic effects of cocaine abuse, including deadly
overdoses of the highly addictive drug, researchers in Korea and
Pennsylvania are reporting. Their study is in the Jan. 2 issue of ACS'
Journal of Proteome Research, a monthly publication.
In the new study, Meeyul Hwang, Chae Ha Yang, and
colleagues note that there is currently no effective medicine for
treating cocaine abuse or addiction. Recent animal studies conducted
by the researchers show that a licorice ingredient called
isoliquiritigenin (ISL) can block the nervous system's production of
dopamine. That neurotransmitter is involved in emotion, movement, and
other brain activities.
Cocaine and other addictive drugs stimulate
dopamine and help produce the pleasurable and addictive effects. Drugs
that block dopamine block this response. The scientists used rats as
model animals to show that rats injected with ISL just prior to
cocaine-administration showed 50 percent less of the behavioral
effects associated with the illicit drug. They also showed that ISL
injections protected nerve cells in the brain from cocaine-associated
damage. - MTS
Soybean product fights abnormal protein involved
in Alzheimer's disease
An enzyme in natto, a soybean product, could
help fight Alzheimer's disease, scientists say.
Image credit: Wikipedia
A vegan food renowned in Asia for its ability to
protect against heart attacks also shows a powerful ability in lab
experiments to prevent formation of the clumps of tangled protein
involved in Alzheimer's disease, scientists in Taiwan are reporting.
Their study is in the Feb. 11 issue of ACS' Journal of Agricultural
and Food Chemistry, a bi-weekly publication.
Rita P. Y. Chen and colleagues point out that
people in Asia have been eating natto - a fermented food made from
boiled soybeans - for more than 1,000 years. Natto contains an enzyme,
nattokinase, that has effects similar to clot-busting drugs used in
heart disease.Nattokinase is sold a dietary supplement to improve the
body's circulatory system. The scientists term this the first study on
whether nattokinase also can dissolve amyloids. Those tangled proteins
are involved in Alzheimer's disease and several other health problems.
In the study, the nattokinase degraded several
kinds of amyloid fibrils, suggesting its possible use in the treatment
of amyloid-related diseases. "Moreover, since natto has been ingested
by humans for a long time, it would be worthwhile to carry out an
epidemiological study on the rate of occurrence of various
amyloid-related diseases in a population regularly consuming natto,"
the scientists say. - JS
Ocean becoming more acidic, potentially
threatening marine life
A dramatic increase in carbon dioxide levels is
making the world's ocean more acidic, which may adversely affect the
survival of marine life and organisms that depend on them, such as
humans. An article on this topic is scheduled for the Feb. 23 issue of
Chemical & Engineering News, ACS' weekly newsmagazine.
In the article, C&EN Associate Editor Rachel
Petkewich notes that the increased use of fossil fuels has caused
levels of carbon dioxide in the atmosphere to nearly double since the
Industrial Revolution. The ocean absorbs large amounts of carbon
dioxide - about 22 million tons a day - causing the water's pH to
decrease or acidify. The pH scale measures how acidic or alkaline
substances are. The pH scale ranges from 0 to 14. A pH of 7 is
neutral. A pH less than 7 is acidic. A pH greater than 7 is alkaline.
The ocean's pH is currently about 8.1, down from 8.2 in the 18th
century, the article notes. Scientists project that the ocean's pH
will fall by about 0.3 more units in the next 50 to 100 years.
Researchers worldwide are now reporting that these
lower pH levels could affect many aspects of the biochemistry,
development, and reproduction of marine organisms, including jellyfish,
sea anemones, plankton, and coral. Lower pH levels may even affect the
ability of the ocean to transmit sound, which could affect the way
some mammals communicate by sonar, the article notes. "To what extent
the oceans will continue to acidify is uncertain and whether marine
organisms can adapt to the changes in store also remains to be seen,"
the article notes.
New biomass heater: A "new era" of efficiency
and sustainability
This is a photo of the charcoal
combustion heater that Japanese scientists say will offer cleaner,
more efficient home heating.
[Image by Amit Suri]
Millions of homes in rural areas of Far Eastern
countries are heated by charcoal burned on small, hibachi-style
portable grills. Scientists in Japan are now reporting development of
an improved "biomass charcoal combustion heater" that they say could
open a new era in sustainable and ultra-high efficiency home heating.
Their study was published in ACS' Industrial & Engineering Chemistry
Research, a bi-weekly journal.
In the study, Amit Suri, Masayuki Horio and
colleagues note that about 67 percent of Japan is covered with forests,
with that biomass the nation's most abundant renewable energy source.
Wider use of biomass could tap that sustainable source of fuel and by
their calculations cut annual carbon dioxide emissions by 4.46 million
tons.
Using waste biomass charcoal, their heater recorded
a thermal efficiency of 60-81 percent compared to an efficiency of
46-54 percent of current biomass stoves in Turkey and the U.S. "The
charcoal combustion heater developed in the present work, with its
fast startup, high efficiency, and possible automated control, would
open a new era of massive but small-scale biomass utilization for a
sustainable society," the authors say. - JS
Antibacterial plaster could put a clean sheen on
walls
Scientists in China are reporting development and
testing of new self-sanitizing plaster with more powerful
antibacterial effects than penicillin. The material could be used in
wall coatings, paints, art works and other products. The study is in
the current issue of ACS' Crystal Growth & Design, a bi-monthly
journal.
Liang-jie Yuan and colleagues note that plaster has
been used for centuries as building material and surfaces for great
works of art, including Michelangelo's famed Sistine Chapel ceiling in
Vatican City. The new, first-of-its kind plaster - formed from
different ingredients from traditional gypsum plaster - still retains
similar mechanical properties while having added antibacterial effects.
Lab tests showed that the so-called "supramolecular"
plaster has a "very broad" antibacterial spectrum, killing five types
of disease-causing bacteria. When compared with penicillin, the
plaster was more effective at controlling growth of four kinds of
bacteria, including dangerous Staphylococcus aureus and Escherichia
coli. "It can be expected that the supramolecular plaster can be used
for building, painting, coating and carving, and the coat, brick, or
art ware constructed by the plaster do not need additive antiseptic or
sterilization," the authors say. - JS
Information superhighway's trash yields a super
highway asphalt
Materials from printed circuit boards used in
electronics, such as computers and cell phones, could be used to
strengthen asphalt paving, scientists report. Above is a
micrograph of the modified asphalt.
Image by The American Chemical Society
Discarded electronic hardware, including bits and
pieces that built the information superhighway, can be recycled into
an additive that makes super-strong asphalt paving material for real
highways, researchers in China are reporting in a new study. It is
scheduled for the Feb. 1 issue of ACS' Environmental Science &
Technology, a semi-monthly journal. They describe development of a new
recycling process that can convert discarded electronic circuit boards
into an asphalt "modifier." The material makes high-performance paving
material asphalt that is cheaper, longer lasting, and more
environmentally friendly than conventional asphalt, the scientists
report.
In the new study, Zhenming Xu and colleagues note
that millions of tons of electronic waste (e-waste) pile up each year.
The printed circuit boards used in personal computers, cell phones,
and other electronic gear, contain toxic metals such as lead and
mercury and pose a difficult disposal problem. The boards also are
difficult to recycle. Xu's group, however, realized that the boards,
which provide mechanical support and connections for transistors and
other electronic components, contain glass fibers and plastic resins
that could strengthen asphalt paving.
The scientists describe a new recycling method that
quickly separates toxic metals from circuit boards, yielding a fine,
metal-free powder. When mixed into asphalt in laboratory tests, the
powder produced a stronger paving material less apt to soften at high
temperatures, the researchers say. - MTS
Frozen smoke: The ultimate sponge for cleaning
up oil spills
Aerogels, a super-lightweight
solid sometimes called "frozen smoke," may capture oil from
wastewater and soak up environmental oil spills.
Image by Wikipedia Commons
Scientists in Arizona and New Jersey are reporting
that aerogels, a super-lightweight solid sometimes called "frozen
smoke," may serve as the ultimate sponge for capturing oil from
wastewater and effectively soaking up environmental oil spills. Their
study is in ACS' Industrial & Engineering Chemistry Research, a
bi-weekly journal.
In the new study, Robert Pfeffer and colleagues
point out that the environmental challenges of oil contamination go
beyond widely publicized maritime oil spills like the Exxon Valdez
incident. Experts estimate that each year people dump more than 200
million gallons of used oil into sewers, streams, and backyards,
resulting in polluted wastewater that is difficult to treat. Although
there are many different sorbent materials for removing used oil, such
as activated carbon, they are often costly and inefficient.
Hydrophobic silica aerogels are highly porous and absorbent material,
and seemed like an excellent oil sponge.
The scientists packed a batch of tiny aerogel beads
into a vertical column and exposed them to flowing water containing
soybean oil to simulate the filtration process at a wastewater
treatment plant. They showed that the aerogel beads absorbed up to 7
times their weight and removed oil from the wastewater at high
efficiency, better than many conventional sorbent materials. - MTS
Greener pesticides, better farming practices
help reduce U.S. pesticide use
Although few consumers realize it, fruits, veggies,
and other agricultural products marketed in the United States today
are grown on farms that use less pesticide than 30 years ago,
according to an article scheduled for the Feb. 16 issue of Chemical &
Engineering News, ACS' weekly newsmagazine.
C&EN Senior Editor Stephen K. Ritter points out in
the magazine's cover story that pesticide use has dropped in the U.S.
due to more efficient pesticides and better agricultural practices.
Pesticide use peaked at 1.46 billion pounds in 1979 and fell to 1.23
billion pounds in 2001 - the last year for which comprehensive data
are available, according to the Environmental Protection Agency. Since
then pesticide use has remained at those lower levels, the article
states.
Several innovations are responsible for this
decline in pesticide use, including better, more selective pesticides
that can be applied at lower rates while having less impact on human
health and the environment. Other factors include a farming practice
called integrated pest management (IPM), which involves withholding
the use of synthetic pesticides only until damage reaches a certain
threshold. In addition, farmers also are using more so-called
biopesticides. These natural substances, derived from plants,
microorganisms, and insects, can combat noxious weeds, insects, and
fungi with less harm to crops and the environment.
This is the Mars Rover at the Udvar-Hazy Center
of the National Air and Space Museum in Chantilly, Va.
[Credit: Wikipedia Commons]
Developed to sniff out extraterrestrial life on
other planets, a portable device known as the Mars Organic Analyzer (MOA)
is taking on a new role in detecting air pollutants on Earth.
Researchers in California report the development of a modified MOA
able to detect polycyclic aromatic hydrocarbons (PAHs), potentially
carcinogenic molecules from cigarette smoke and wood smoke, volcanic
ash, and other sources. The report appeared in the Jan. 15 issue of
ACS' semi-monthly journal Analytical Chemistry.
In the report, Richard A. Mathies and colleagues
indicate that current earthbound PAH detection focuses on the cleanup
of environmental contamination sites. On other planets, the
concentration of organic PAH molecules can provide valuable insight
into environmental conditions and the potential for extraterrestrial
life. But existing PAH detection methods are slow and costly.
Scientists thus are seeking an inexpensive, rapid and nondestructive
technique for the measurement of PAH contamination.
The researchers tested samples from Lake Erie and a
hydrothermal vent from the Gulf of California, as well as a Martian
analogue sample from the Mars-like Atacama Desert, one of the driest
spots on earth. They found that the detection sensitivity of the
device was on par with current laboratory methods. "The method of PAH
analysis developed here significantly advances the MOA's capabilities
for organic carbon detection and may also prove useful for
environmental monitoring," says Mathies. - AD
Natural solar collectors on butterfly wings
inspire more powerful solar cells
This is a close-up of the scales of a butterfly
wing. These scales have inspired more powerful solar cells.
[Credit: Michael Apel, Wikipedia Commons]
The discovery that butterfly wings have scales that
act as tiny solar collectors has led scientists in China and Japan to
design a more efficient solar cell that could be used for powering
homes, businesses, and other applications in the future. Their study
appeared in the Jan. 13 issue of ACS' Chemistry of Materials, a
bi-weekly journal.
In the study, Di Zhang and colleagues note that
scientists are searching for new materials to improve light-harvesting
in so-called dye-sensitized solar cells, also known as Gr?zel cells
for inventor Michael Gr?zel. These cells have the highest
light-conversion efficiencies among all solar cells - as high as 10
percent.
The researchers turned to the microscopic solar
scales on butterfly wings in their search for improvements. Using
natural butterfly wings as a mold or template, they made copies of the
solar collectors and transferred those light-harvesting structures to
Gr?zel cells. Laboratory tests showed that the butterfly wing solar
collector absorbed light more efficiently than conventional
dye-sensitized cells. The fabrication process is simpler and faster
than other methods, and could be used to manufacture other
commercially valuable devices, the researchers say. - MTS
Nanotubes trigger biochemical "cross talk" for
consumer protection tests
Researchers in West Virginia and Japan are
reporting an advance toward a blood test that could help protect
consumers from new products containing potentially harmful kinds of
nanotubes. These ultra small wisps of carbon - 1/5,000th the width a
single human hair - may become the basis for multibillion-dollar
medical, consumer electronics, and other industries in the future.
Their report is appeared in the Jan. 14 issue of
ACS' Nano Letters, a monthly journal.
Petia Simeonova and colleagues cite hints from past
studies that nanotubes are toxic to the lungs of laboratory animals.
Those findings emphasized the need for tests to check on the toxicity
before products containing these particles hit the market.
In the new research, scientists deposited nanotubes
in the lung of lab mice, and discovered the existence of a "cross-talk"
mechanism, in which the animals' lungs alerted the rest of the body to
the nanotubes presence. The alert caused specific genes in the animals
to kick into action and produce certain proteins. The resulting
biochemical signature of nanotube exposure could become a biomarker
for exposure to harmful nanoparticles, the researchers say. -
MTS
Toward "invisible electronics" and transparent
displays
Researchers in California are reporting an advance
toward the long-sought goal of "invisible electronics" and transparent
displays, which can be highly desirable for heads-up displays,
wind-shield displays, and electronic paper. The scientists describe
development of tiny, transparent electronic circuits - the most
powerful of their kind to date - that could pave the way for
transparent electronics and other futuristic applications, including
flexible electronic newspapers and wearable clothing displays. Their
study appeared in the Jan. 27 issue of ACS Nano, a monthly journal.
In the new study, Chongwu Zhou and colleagues point
out that although scientists have previously developed nano-sized
transparent circuits, previous versions are limited to a handful of
materials that are transparent semiconductors.
The researchers describe the development of
transparent thin-film transistors (TTFTs) composed of highly aligned,
single-walled carbon nanotubes - each about 1/50,000th the width of a
single human hair. They are transparent, flexible, and perform well.
Laboratory experiments showed that TTFTs could be easily applied to
glass and plastic surfaces, and showed promise in other ways for a
range of possible practical applications. - MTS
Nanoparticles in dietary supplements cause
health concerns, regulatory challenges
An increase in the number of dietary supplements
made with nanoparticles - so called "nanoceuticals" - is raising
growing concerns about their potential for toxicity in the wake of
little government oversight, according to an article scheduled for the
Feb. 9 online issue of Chemical & Engineering News, ACS' weekly
newsmagazine.
In the article, C&EN Associate Editor Britt
Erickson notes that manufacturers of dietary supplements are
increasingly using nano-sized particles (about 1/5000th the width of a
single human hair) to boost nutrient absorption, enhance mental focus
and creativity, and other health-promoting functions. One nonprofit
organization that tracks nanotechnology estimates at least 44 "nanoceuticals"
are currently on the market, quadruple the number that existed three
years ago.
But consumers have no way of knowing whether a "nanoceutical"
is safe or whether it does what it claims to do, the article notes.
Unlike drugs, dietary supplements do not need to be reviewed by the
Food and Drug Administration for safety and effectiveness before
marketing. This lack of government oversight, coupled with growing
concerns about the potential toxicity of nanoparticles, has led
consumer groups to urge regulators to do more to ensure that
nanoceuticals are safe and effective.
Notes one regulatory expert, "If FDA waits much
longer, we are going to be faced with hundreds of products and
hundreds of companies and a much more difficult situation."
An edible fungus added to grapefruit juice could
reduce side effects people have when drinking that juice while
taking prescription drugs, scientists report.
Image credit: Royal Botanic Gardens, Melbourne
Scientists in Florida report that adding an edible
mushroom-like fungus to grapefruit juice may help to reduce the
serious side effects that can occur when people taking certain
prescription drugs drink grapefruit juice. Their study is in the
January 14 edition of the ACS' bi-weekly Journal of Agricultural and
Food Chemistry.
In the study, Kyung Myung and colleagues explain
that furanocoumarins (FCs) - chemicals found in grapefruit and some
other citrus - block a key enzyme critical for metabolizing, or
breaking down, certain prescription medications. This "grapefruit/drug"
interaction - sometimes called the "grapefruit effect" - can turn
normal drug doses into toxic overdoses. Researchers have tried to
remove FCs using chemical, physical and microbiological methods. Myung
and colleagues, for example, had previously discovered that an
inedible fungus can be used to remove most of the FCs from grapefruit
juice.
Now they report that the edible fungus Morchella
esculenta, which is from the same major fungal group as the previously
tested inedible fungus, removed most of the furanocoumarins from the
grapefruit juice. It also reduced grapefruit juice's inhibition of the
enzyme by 60 percent. Dried M. esculenta also worked, leading the
researchers to suggest that it could be useful in removing the
compound from grapefruit juice and identifying the specific components
in the fungi that bind to furanocoumarins. - KSD
Researchers in Australia are reporting an advance
toward the first urine test for diagnosing coronary artery disease
(CAD), the condition responsible for most of the 1.5 million heart
attacks that occur in the United States each year. The test could save
lives in the future by allowing earlier diagnosis and monitoring of
the disease, which is the No. 1 cause of death in the United States,
the researchers say. Their report is in the Nov. 19, 2008 issue of ACS'
Journal of Proteome Research, a monthly publication.
In the new study, Karlheinze Peter and colleagues
note that the most reliable test for diagnosing CAD is angiography, an
invasive test in which doctors inject special dyes into the body to
visualize, via X-rays, fatty plaque deposits in the arteries of the
heart. However, the technique is invasive, expensive, time-consuming,
and may miss CAD in its earliest stages, they say.
To develop a faster, more convenient test, the
scientists collected urine samples from a group of 67 patients - 41
with CAD and 26 without - and analyzed the samples for differences in
protein content. Using a newly developed method, they identified a
group of 17 peptides (building blocks of proteins) that appear to be
directly associated with CAD. These urine-based peptides indicated the
presence of the disease with an 84 percent accuracy rate when compared
to CAD cases confirmed using angiography, the researchers say,
underscoring their potential for diagnostic screening. - MTS
Burying crop residues at sea may help reduce
global warming
Burying crop residues at sea may help reduce
carbon dioxide levels in an effort to fight global warming.
Image credit: iStockphoto
Imagine a massive international effort to combat
global warming by reducing carbon dioxide - build up in the atmosphere.
It involves gathering billions of tons of cornstalks, wheat straw, and
other crop residue from farm fields, bailing it, shipping the material
to seaports, and then burying it in the deep ocean. Scientists in
Washington and California have concluded that this Crop Residue
Oceanic Permanent Sequestration (CROPS) approach is the only practical
method now available for permanently sequestering, or isolating, the
enormous quantities of CO2 necessary to have a real impact on global
warming.
In a report scheduled for the Feb. 15 issue of ACS'
Environmental Science & Technology, a semi-monthly journal, Stuart
Strand and Gregory Benford conclude that (CROPS) could reduce global
carbon dioxide accumulation by up to 15 percent per year. Plants
remove carbon dioxide from the atmosphere during photosynthesis, and
release it when they decay. Ocean burial would prevent that carbon
dioxide from re-entering the atmosphere.
After comparing known methods for carbon dioxide
sequestration on the basis of efficiency, long-term effectiveness,
practicality, and cost, the researchers concluded that CROPS is the
only method feasible with existing technology. CROPS would be 92
percent efficient in sequestering crop residue carbon. They recommend
that crop residue sequestration and its effects on the ocean should be
investigated further and its implementation encouraged. - MTS
Quantum dots may be toxic to cells, environment
under certain conditions
Researchers in Texas are reporting that quantum
dots (QDs) - a product of the revolution in nanotechnology
increasingly used in electronics, solar cells, and medical imaging
devices - may be toxic to cells under acidic or alkaline conditions.
Their study, the first to report on how different pH levels may affect
the safety of QDs, appears in the Jan.15 issue of ACS' Environmental
Science & Technology, a semi-monthly journal.
In the new study, Pedro Alvarez, Shaily Mahendra,
and colleagues note that QDs are semiconductor nanocrystals composed
of a metal core surrounded by a shell composed of zinc or cadmium
sulfide.
Scientists are increasingly concerned that these
submicroscopic dots, about 1/50,000th the width of a human hair, could
decompose during normal use or after disposal. That decomposition
could release toxic metals into the environment, posing a health risk
to humans and animals.
To explore this concern, the scientists exposed two
common types of bacteria that serve as models of cell toxicity and
indicators of environmental health to QDs under different conditions
of acidity and alkalinity. At near neutral pH levels, bacteria exposed
to QDs experienced decreased rates of growth, but did not die. However,
at moderately acidic or alkaline conditions, many of the QD-exposed
bacteria died as QDs shells decomposed, releasing their content of
toxic metals. However, proteins and natural organic matter may be able
to mitigate toxicity by complexing metal ions or coating particles.
The study cautions, "the release of toxic inorganic constituents
during their weathering under acidic or alkaline conditions in the
human body or the environment may cause unintended harm that might be
difficult to predict with short-term toxicity tests." - MTS
New NASCAR materials may save lives on the race
track and highway
New materials for NASCAR promise to save lives and
reduce injuries in automobile racing - a popular sport with a fan-base
of 75 million - and everyday driving, according to an article
scheduled for the Feb. 2 issue of Chemical & Engineering News, ACS'
weekly newsmagazine. NASCAR's new racing season begins Feb. 7.
In the magazine's cover story, C&EN Associate
Editor Bethany Halford points out that for many years NASCAR (the
National Association for Stock Car Auto Racing) left safety
innovations in the hands of mechanics and engineers tinkering in the
garage. These innovations haven't kept pace with NASCAR's push for
faster cars, the article notes. But a series of spectacular crashes
that claimed the lives of several NASCAR stars brought about a new
focus on safety.Researchers recently established the NASCAR R&D Center
to focus on safety innovations, leading to a major redesign of the
stockcar to make it more crash resistant. Other innovations include
clothing (for drivers and crews) that is more fire-resistant and the
development of stronger safety barriers for the track walls. Some of
these materials could be used in future passenger cars and highways,
the article suggests.
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