The Uncalculability of Electron Systems
Theoretical physicists of the Max Planck Institute of Quantum Optics reveal limitations of Density Functional Theory using Quantum Information Theory tools.
Bringing objects close together can boost radiation heat transfer, according to new study that shows breakdown in Planck's law.
Image: A diagram of the setup, including a cantilever from an atomic force microscope, used to measure the heat transfer between objects separated by nanoscale distances.
[Image credit: Sheng Shen; MIT]
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Chemistry & Biology
Nanogap Sensor Array
New ultrasensitive electronic sensor array speeds up DNA detection: Singapore scientists developed cost-effective technology for disease diagnosis and biological research.
Learning from evolution: Fine-tuning an anti-cancer drug.
Researchers have determined in detail how the
bacteria-derived molecule Salinosporamide A disables the
intracellular waste-processing plants called proteasomes.
Field trials in the US show that
enhancing the attractiveness of maize roots to
insect-killing nematodes can effectively fend off Western
corn rootworm.
Image: The Western corn
rootworm (insert) is a devastating pest of maize roots.
[Credit: Matthias Held and Sergio
Rasmann, University of Neuch?el, Switzerland]
Epoxides in Atmospheric Chemistry
Caltech researchers show how organic carbon compounds emitted by trees affect air quality. The research provides first-ever glimpse of role of epoxides in atmospheric chemistry.
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Chemistry & Geology
Carbonyl Sulfide
The greenhouse gas that saved the world: Chemistry researchers uncover why the archean world was not frozen solid.
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Chemistry & Nanotechnology
Self-Destructing Messages
Light-reactive coatings make metal nanoparticles into inks for self-erasing paper.
Low-cost Photovoltaics
Lower-cost solar cells to be printed like newspaper, painted on rooftops.
Nanocrystal Growth
Berkeley Lab Researchers Record First Real-Time Direct Observations of Nanocrystal Growth in Solution.
Plastic Solar Cells
Plastics that convert light to electricity could have a big impact.
Nuisance or nutrient? Kudzu shows promise as a
dietary supplement
Kudzu, a nuisance vine, shows
promise as a dietary supplement that fights an unhealthy condition
called metabolic syndrome.
[Credit: Wikimedia Commons]
Kudzu, the nuisance vine that has overgrown almost
10 million acres in the southeastern United States, may sprout into a
dietary supplement. Scientists in Alabama and Iowa are reporting the
first evidence that root extracts from kudzu show promise as a dietary
supplement for a high-risk condition - the metabolic syndrome - that
affects almost 50 million people in the United States alone. Their
study appears in the current issue of ACS' Journal of Agricultural and
Food Chemistry, a bi-weekly publication.
J. Michael Wyss and colleagues note in the new
study that people with metabolic syndrome have obesity, high blood
pressure, high blood cholesterol, and problems with their body's
ability to use insulin. Those disorders mean a high risk for heart
attacks, strokes, and other diseases. Scientists have been seeking
natural substances that can treat the metabolic syndrome. The new
study evaluated kudzu root extracts, which contain healthful
substances called isoflavones. People in China and Japan long have
used kudzu supplements as a health food.
The study found that a kudzu root extract had
beneficial effects lab rats used as a model for research on the
metabolic syndrome. After two months of taking the extract, the rats
had lower cholesterol, blood pressure, blood sugar, and insulin levels
that a control group not given the extract. Kudzu root "may provide a
dietary supplement that significantly decreases the risk and severity
of stroke and cardiovascular disease in at-risk individuals," the
article notes.
People vary widely in ability to eliminate
arsenic from the body
Large variations exist in
people's ability to eliminate arsenic (sample shown) from the body,
a new study shows.
[Credit:
Wikimedia Commons]
Large variations exist in peoples' ability to
eliminate arsenic from the body, according to a new study that
questions existing standards for evaluating the human health risks
from the potentially toxic substance. The study found that some people
eliminate more than 90 percent of the arsenic consumed in the diet.
Others store arsenic in their bodies, where it can have harmful
effects. The research, based on the first application of new methods
for studying arsenic, is scheduled for the Sept. 21 issue of ACS's
Chemical Research in Toxicology, a monthly journal.
In the study, Kevin Francesconi and colleagues point out that drinking
water in many parts of the world, including some regions of the United
States, contain amounts of arsenic that exceed the World Health
Organization's maximum acceptable levels. Consumption of seafood, the
article notes, is another major source of arsenic contamination.
Health effects from chronic arsenic exposure include skin and internal
cancers, cardiovascular disease, and possibly diabetes, it adds.
The scientists describe monitoring arsenic excretion in the urine of
human volunteers. They found that ability to eliminate arsenic from
the body varied greatly, with some participants excreting up to 95
percent of the ingested arsenic but others eliminating as little as
four percent. "This observed individual variability in handling [arsenic]
exposure has considerable implications for the risk assessment of
arsenic ingestion," the paper states. It adds that further study is
needed to assess potential risks to humans consuming seafood products.
"The data presented here suggest that the long held view that seafood
arsenic is harmless because it is present mainly as organoarsenic
compounds needs to be reassessed."
Heat forms potentially harmful substance in
high-fructose corn syrup
A new study shows that heat can
produce a potentially toxic substance in high-fructose corn syrup
that may kill honeybees and might also endanger human health.
[Credit: Wikimedia Commons]
Researchers have established the conditions that
foster formation of potentially dangerous levels of a toxic substance
in the high-fructose corn syrup (HFCS) often fed to honey bees. Their
study, which appears in the current issue of ACS' bi-weekly Journal of
Agricultural and Food Chemistry, could also help keep the substance
out of soft drinks and dozens of other human foods that contain HFCS.
The substance, hydroxymethylfurfural (HMF), forms mainly from heating
fructose.
In the new study, Blaise LeBlanc and Gillian
Eggleston and colleagues note HFCS's ubiquitous usage as a sweetener
in beverages and processed foods. Some commercial beekeepers also feed
it to bees to increase reproduction and honey production. When exposed
to warm temperatures, HFCS can form HMF and kill honeybees. Some
researchers believe that HMF may be a factor in Colony Collapse
Disorder, a mysterious disease that has killed at least one-third of
the honeybee population in the United States.
The scientists measured levels of HMF in HFCS
products from different manufacturers over a period of 35 days at
different temperatures. As temperatures rose, levels of HMF increased
steadily. Levels jumped dramatically at about 120 degrees Fahrenheit.
"The data are important for commercial beekeepers, for manufacturers
of HFCS, and for purposes of food storage. Because HFCS is
incorporated as a sweetener in many processed foods, the data from
this study are important for human health as well," the report states.
It adds that studies have linked HMF to DNA damage in humans. In
addition, HMF breaks down in the body to other substances potentially
more harmful than HMF.
A better test to detect DNA for diagnosing
disease, investigating crimes
Scientists have developed a new
electronic sensor that shows promise as a better way to detect DNA
for diagnosing disease and investigating crimes.
[Credit: Wikimedia Commons]
Researchers in Singapore are reporting development
of a new electronic sensor that shows promise as a faster, less
expensive, and more practical alternative than tests now used to
detect DNA. Such tests are done for criminal investigation, disease
diagnosis, and other purposes. The new lab-on-a-chip test could lead
to wider, more convenient use of DNA testing, the researchers say.
Their study is scheduled for the Sept. 2 issue of the Journal of the
American Chemical Society, a weekly publication.
In the new study, Zhiqiang Gao and colleagues note
that current methods for detecting DNA involve the used of the
polymerase chain reaction (PCR). This technique "amplifies" or makes
multiple copies of trace amounts of DNA, much as a photocopier
produces multiple copies of documents, in order to detect the genetic
material more easily. The amplification step is one reason why tests
involving PCR can be too expensive, cumbersome, and imprecise for
wider use.
The researchers describe development of a so-called
"nanogap sensor" that appears to overcome those obstacles. The process
uses a pair of micro-sized metal electrodes separated by a nanogap,
1/50,000 the width of a human hair, in combination with special
chemical probes, to capture tiny segments of DNA. The newly formed
"circuit" then translates the presence of DNA into an electrical
signal so that it can be measured by a computer. In laboratory tests,
the sensor showed "excellent" sensitivity at detecting trace amounts
of human DNA and may eliminate the need for DNA amplification
altogether, the researchers say.
This pinhead-sized worm could
play an important role in discovering and testing new antibiotics,
researchers say.
[Image credit: Wikimedia Commons]
In an advance that could help ease the antibiotic
drought, scientists in Massachusetts are describing successful use of
a test that enlists pinhead-sized worms in efforts to discover badly
needed new antibiotics. Their study appeared in ACS Chemical Biology,
a monthly journal.
Frederick Ausubel and colleagues note in the new
study that existing methods for identifying germ-fighting drugs
involve adding the potential drug to cultures of bacteria or cells and
watching the results. These tests sometimes do not work well. They may
give passing grades to potential drugs that are toxic, or that fight
bacteria in the same ways as existing antibiotics that are loosing
effectiveness against drug-resistant bacteria. A much better test
would involve screening of potential new antibiotics in living animals
infected with bacteria to see the effects on the entire body of the
animal.
The scientists describe successful use of such a
whole-animal high throughput screening test - automated with a robot -
to test the effects of 37,000 potential drugs on C. elegans (a type of
worm) infected with E. faecalis (a type of bacteria). That bacterium
causes life-threatening infections in humans. C. elegans are tiny
nematode worms that are widely used in scientific research. The tests
identified 28 potential new drugs never before reported to have
germ-fighting effects. Some of the potential new drugs worked in ways
that appeared to be totally different than existing antibiotics.
Growing evidence of marijuana smoke's potential
dangers
Smoking marijuana causes more
damage to cells and DNA than smoking tobacco, scientists say.
[Image credit: Wikimedia Commons]
In a finding that challenges the increasingly
popular belief that smoking marijuana is less harmful to health than
smoking tobacco, researchers in Canada are reporting that smoking
marijuana, like smoking tobacco, has toxic effects on cells. Their
study is scheduled for the Aug. 17 issue of ACS' Chemical Research in
Toxicology, a monthly journal.
Rebecca Maertens and colleagues note that people
often view marijuana as a "natural" product and less harmful than
tobacco. As public attitudes toward marijuana change and legal
restrictions ease in some countries, use of marijuana is increasing.
Scientists know that marijuana smoke has adverse effects on the lungs.
However, there is little knowledge about marijuana's potential to
cause lung cancer due to the difficulty in identifying and studying
people who have smoked only marijuana.
The new study begins to address that question by
comparing marijuana smoke vs. tobacco smoke in terms of toxicity to
cells and to DNA. Scientists exposed cultured animal cells and
bacteria to condensed smoke samples from both marijuana and tobacco.
There were distinct differences in the degree and type of toxicity
elicited by marijuana and cigarette smoke. Marijuana smoke caused
significantly more damage to cells and DNA than tobacco smoke, the
researchers note. However, tobacco smoke caused chromosome damage
while marijuana did not.
Re-examination of T. rex verifies disputed
biochemical remains
A new analysis of the
remains of a T. rex has confirmed traces of protein from blood and
bone, tendons, or cartilage.
[Image credit: Wikimedia Commons]
A new analysis of the remains of a Tyrannosaurus
rex (T. rex) that roamed Earth 68 million years ago has confirmed
traces of protein from blood and bone, tendons, or cartilage. The
findings, scheduled for publication in the Sept. 4 issue of ACS'
monthly Journal of Proteome Research, is the latest addition to an
ongoing controversy over which biochemical remnants can be detected in
the dino.
In the study, Marshall Bern, Brett S. Phinney and
David Goldberg point out that the first analysis in 2007 of a
well-preserved, fossilized T. rex bone identified traces of seven
distinct protein fragments, or peptides, from collagen. That material
is one of the primary components of bone, tendons and other connective
tissue. However, later studies disputed that finding, suggesting that
it was a statistical fluke or the result of contamination from another
laboratory sample.
The scientists describe reanalysis of the T. rex
data and also report finding evidence of substances found in collagen.
"In summary, we find nothing obviously wrong with the Tyrannosaurus
rex [analysis from 2007]," the report states. "The identified peptides
seem consistent with a sample containing old, quite possibly very
ancient, bird-like bone, contaminated with only fairly explicable
proteins. Hemoglobin and collagen are plausible proteins to find in
fossil bone, because they are two of the most abundant proteins in
bone and bone marrow."
Freshly crushed garlic better for the heart than
processed
Freshly crushed garlic is better
for the heart than dried garlic, scientists are reporting.
[Image credit: Wikimedia Commons]
A new study reports what scientists term the first
scientific evidence that freshly crushed garlic has more potent
heart-healthy effects than dried garlic. Scheduled for the Aug. 12
issue of the Journal of Agricultural and Food Chemistry, it also
challenges the widespread belief that most of garlic's benefits are
due to its rich array of antioxidants. Instead, garlic's heart-healthy
effects seem to result mainly from hydrogen sulfide, a chemical
signaling substance that forms after garlic is cut or crushed and
relaxes blood vessels when eaten.
In the study, Dipak K. Das and colleagues point out
that raw, crushed garlic generates hydrogen sulfide through a chemical
reaction. Although best known as the stuff that gives rotten eggs
their distinctive odor, hydrogen sulfide also acts as a chemical
messenger in the body, relaxing blood vessels and allowing more blood
to pass through. Processed and cooked garlic, however, loses its
ability to generate hydrogen sulfide.
The scientists gave freshly crushed garlic and
processed garlic to two groups of lab rats, and then studied how well
the animals' hearts recovered from simulated heart attacks. "Both
crushed and processed garlic reduced damage from lack of oxygen, but
the fresh garlic group had a significantly greater effect on restoring
good blood flow in the aorta and increased pressure in the left
ventricle of the heart," Das said.
'Artificial Golgi' may provide new insight into
key cell structure
Researchers have developed an
artificial version of the Golgi organelle, shown in this
illustration of a cell cross-section. The device could lead to a
better method for producing heparin, they say.
[Image credit: The American
Chemical Society]
Scientists in New York and North Carolina are
reporting assembly of the first functioning prototype of an artificial
Golgi organelle. That key structure inside cells helps process and
package hormones, enzymes, and other substances that allow the body to
function normally. The lab-on-a-chip device could lead to a faster and
safer method for producing heparin, the widely used anticoagulant or
blood thinner, the researchers note. Their study is scheduled for the
Aug. 12 issue of the Journal of the American Chemical Society, a
weekly publication.
The Golgi organelle is named for Camillo Golgi, the
Italian scientist and Nobel Prize winner who discovered the structure
in 1898. It is composed of a network of sacs, stacked like a deck of
playing cards, located inside cells. In the new study, Robert Linhardt
and colleagues point out that Golgi bodies are one of the most poorly
understood organelles (specialized structures inside cells) in the
human body. Scientists already know, however, that the organelles play
a key role in producing heparin, a substance that helps prevent
clotting.
The researchers describe development of a prototype
lab-on-a-chip device that closely mimics the natural Golgi apparatus.
They showed in lab tests that the device could quickly and efficiently
produce heparin. It did so in an assembly-line fashion using a
combination of enzymes, sugars and other raw materials and
demonstrated that the substance has a strong clot-fighting potential.
In the future, an "artificial Golgi" could lead to a faster and safer
method for producing heparin, the scientists suggest.
A substance made from shrimp
shells may transform biodiesel production into a faster, less
expensive and more eco-friendly process, researchers are reporting.
[Image credit: Wikimedia Commons]
Call it a "shrimp cocktail" for your fuel tank.
Scientists in China are reporting development of a catalyst made from
shrimp shells that could transform production of biodiesel fuel into a
faster, less expensive, and more environmentally friendly process.
Their study is scheduled for the Aug. 20 issue of ACS' Energy & Fuels,
a bi-monthly journal.
Xinsheng Zheng and colleagues note that an
energy-hungry world, concerned about global warming, increasingly puts
its future fuel hopes on renewable fuels like biodiesel. Today's
biodiesel production processes, however, require catalysts to speed up
the chemical reactions that transform soybean, canola, and other plant
oils into diesel fuel. Traditional catalysts cannot be reused and must
be neutralized with large amounts of water - another increasingly
scarce resource - leaving behind large amounts of polluted wastewater.
The researchers describe development of a new
catalyst produced from shrimp shells. In laboratory tests, the shrimp
shell catalysts converted canola oil to biodiesel (89 percent
conversion in three hours) faster and more efficiently than some
conventional catalysts. The new catalysts also can be reused and the
process minimizes waste production and pollution, the scientists note.
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