Materials researchers at the National Institute of Standards and Technology (NIST) have developed a simplified, low-cost process for producing high-quality, water-soluble "quantum dots" for biological research.
A team of Penn State researchers has shown for the first time that the entire class of non-magnetic materials, such as those used in some computer components, could have considerably more uses than scientists had thought.
The findings are important because they reveal previously unknown information about the structure of these materials, expanding the number of properties and uses that they potentially could have.
Scientists report in an open access article that low doses of resveratrol can potentially boost the quality of life by improving heart health in old age.
The ability to see is based on molecules in the eye that flip from one conformation to another when exposed to visible light. Now, a new technique for attaching light-sensitive organic molecules to metal surfaces allows the molecules to be switched between two different configurations in response to exposure to different wavelengths of light.
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Chemistry & Environment
Proteins can reduce the toxic content in rice
Researchers at the University of Gothenburg have found the proteins which govern how plants absorb arsenic. With this discovery, a variety of rice can be developed which does not absorb the toxin, even if it is irrigated with untreated water.
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ACS News (open access articles):
The tummy's taste for red wine with red meat
Scientists are reporting that red
wine can block formation of harmful substances released during
digestion of fat in meat.
Image by public-domain-photos.com
What happens when red wine meets red meat? If the
rendezvous happens in the stomach, scientists in Israel are reporting,
wine's bounty of healthful chemical compounds may thwart formation of
harmful substances released during digestion of fat in the meat. The
study, which reinforces the benefits of consuming wine and other foods
rich in so-called polyphenols during meals, appears in the June 11
issue of ACS's bi-weekly Journal of Agricultural and Food Chemistry.
In the study, Joseph Kanner and colleagues point
out that scientists attribute wine's health benefits, including
protection against cancer and heart disease, to its high levels of
polyphenols, powerful antioxidants found in fruits and vegetables.
However, the body does not absorb polyphenols easily, and scientists
have been puzzled about how and where these substances exert their
beneficial effects.
The researchers found an explanation in experiments
with laboratory rats fed either red meat or meat combined with red
wine concentrate. Wine concentrate substantially reduced formation of
two byproducts of fat digestion, malondialdehyde and hydroperoxide,
which are toxic to cells. The researchers say the stomach acts as a "bioreactor"
that facilitates the beneficial effects of polyphenols. The
polyphenols work not only to prevent generation of cytotoxic compounds,
but also as compounds which prevent the absorption of cytotoxic
compounds from the gastrointestinal tract into the blood stream. - MTS
Proteins could relate to increased longevity in
women
Scientists in Spain and Italy have identified a
group of proteins in laboratory rats that could help explain two
enduring medical mysteries - why women live longer than men and why
calorie restriction stands as the only proven method of extending
longevity. Their study, which could help scientists understand the
biochemical underpinnings of aging, is scheduled for the July 3 issue
of ACS' monthly Journal of Proteome Research.
In the study, Adamo Valle and colleagues point out
that women, on average, live years longer than men. Previous studies
also have shown that diets extremely low in calories consistently
increase maximum life spans in a wide range of animals. Scientists
have speculated that the explanation may involve hormones, stress,
cardiovascular protection and other factors.
Using lab rats as stand-ins for humans, the
researchers found that the livers of both female rats and
calorie-restricted rats produced different levels of 27 proteins than
male rats or those on a normal diet. The findings suggest that a
previously unrecognized set of cellular pathways may be involved in
the longevity boost from being female and eating a sparse diet, the
study says, suggesting that these insights could lead to new ways of
boosting human longevity. - JS
Toward perfumed-clothing: Fabric-friendly "microcapsules"
hide unpleasant body odors
Researchers in Portugal are reporting development
of a new type of "microcapsule" filled with perfume and embedded in
fabric for production of scented suits, socks, undergarments and other
clothing. The same technology can be used in many other applications,
such as to mask unpleasant body odors when using textile products.
They describe the material, which is also environmentally-friendly, in
a report scheduled for the July 2 issue of ACS' Industrial &
Engineering Chemistry Research, a bi-weekly journal.
In the new study, Alirio E. Rodrigues and
colleagues point out that microcapsules, or submicroscopic shells,
have been used for years to deliver fragrances in commercial products
ranging from scratch-and-sniff stickers to the peel-apart fragrance
samples found in magazine inserts. But current microcapsules are made
using formaldehyde, a known cancer-causing agent that is also an
environmental hazard. Safer, more effective materials are needed to
extend this scented technology to textiles, the researchers say.
The researchers identified polyurethane-urea, a
type of environmentally-friendly plastic that is compatible with
fabrics, as a solution. They used the material to prepare
microcapsules containing limonene, the familiar scent abundant in
lemons and widely-used in perfumes, and applied the capsules onto wool
and polyester samples. In laboratory tests, the microcapsules showed
good performance in terms of prolonged fragrance production and
durability, the researchers say. - MTS
Toward long-range beach forecasts on bacterial
contamination
Scientists are reporting
development of a water quality prediction method so that
vacationers can better plan beach holidays.
Image by public-domain-photos.com
Long-range forecasts of beach bacterial
contamination are inching closer to reality because of a new water
quality prediction method scheduled for publication in the July 15
issue of the ACS' Environmental Science & Technology, a semi-monthly
journal. "For the first time, this study showed that bacteria
concentrations could be forecasted with reasonable accuracy, hastening
the day when people will be able to better plan their beach holidays,"
the report says.
In the new study, Walter E. Frick and colleagues
explain that decisions on whether beaches are safe for swimming, or
should be closed due to fecal contamination, are based on testing the
water for E. coli. However, existing tests take 24 hours to complete,
providing a backward-only look at conditions the previous day. As a
result, beaches may be closed unnecessarily when water quality has
improved, or open when water quality has declined and disease-causing
microorganisms are present.
Building on pioneering modeling studies in the
Great Lakes by the U. S. Geological Survey (USGS) and others, the
researchers developed "Virtual Beach," a broadly-applicable software
tool for the development of models that predict concentrations of
indicators of fecal contamination at beaches. Unique features of
Virtual Beach are the ability to evaluate a dynamic modeling approach
for using short-term data sets to rapidly develop reliable models, and
the use of available weather and marine forecast variables to forecast
E. coli levels 24 hours or more in advance.
Evaluations of Virtual Beach were accomplished
using data collected by USGS, NOAA and other sources for Huntington
Beach on Lake Erie in northeastern Ohio. During the 42-day study,
models developed by Virtual Beach correctly forecasted 24 hours in
advance eight instances when E. coli levels exceeded safety standards.
These results exceeded the accuracy of traditional sampling methods
and approximately matched the accuracy of nowcasting (real-time
predictions), according to the researchers. - DD
A healthier July Fourth: Eco-friendly fireworks
and flares poised to light up the sky
Scientists plan to replace
potassium perchlorate, a harmful substance widely used in
fireworks, with cleaner, less toxic materials.
Image by Wikimedia Commons
From the rockets' red glare to bombs bursting in
air, researchers are developing more environmentally friendly
fireworks and flares to light up the night sky while minimizing
potential health risks, according to an article scheduled for the June
30 issue of Chemical & Engineering News. Some eco-friendly fireworks
may soon appear at a Fourth of July display or rock concert near you.
In the C&EN cover story, Associate Editor Bethany
Halford points out that fireworks, flares and other so-called
pyrotechnics commonly include potassium perchlorate to speed up the
fuel-burning process. But some studies have linked perchlorate, which
can accumulate in the soil, air and water, to thyroid damage.
Pyrotechnics also contain color-producing heavy metals, such as barium
and copper, which have also been linked to toxic effects.
Researchers recently developed new pyrotechnic
formulas that replace perchlorate with nitrogen-rich materials or
nitrocellulose that burn cleaner and produce less smoke. At the same
time, these nitrogen-rich formulas also use fewer color-producing
chemicals, dramatically cutting down on the amount of heavy metals
used and lowering their potentially toxic effects. Some of these
fireworks are already being used at circuses, rock concerts, and other
events. The big challenge in developing these "eco-friendly"
pyrotechnics is making them as cost-effective as conventional
fireworks while maintaining their dazzle and glow, the article states.
Prions are not degraded by conventional sewage
treatment processes
Wastewater treatment plants do
not reduce harmful proteins called prions that cause incurable
brain infections, such as Mad Cow disease, scientists report.
Photo by Katherine McMahon
Scientists in Wisconsin are reporting in a paper
scheduled for the July 1 issue of ACS' Environmental Science &
Technology that typical wastewater treatment processes do not degrade
prions. Prions, rogue proteins that cause incurable brain infections
such as Mad Cow disease and its human equivalent, variant
Creutzfeldt-Jakob Disease, are difficult to inactivate, resisting
extreme heat, chemical disinfectants, and irradiation. Until now,
scientists did not know whether prions entering sewers and septic
tanks from slaughterhouses, meatpacking facilities, or private game
dressing, could survive and pass through conventional sewage treatment
plants.
Joel Pedersen and colleagues used laboratory
experiments with simulated wastewater treatment to show that prions
can be recovered from wastewater sludge after 20 days, remaining in
the "biosolids," a byproduct of sewage treatment sometimes used to
fertilize farm fields.
Although emphasizing that prions have never been
reported in wastewater treatment plant water or biosolids, the
researchers note that existing tests are not sufficiently sensitive to
detect the extremely low levels of prions possible in those materials.
- AD
New test for more reliable product expiration
labels
Researchers have developed a new,
more reliable test for predicting the shelf-life of
light-sensitive food and drink products.
Photo by public-domain-photos.com
Beer gets a "skunky" taste. Wine develops an
unpleasant flavor termed "light-struck." And exposure to light causes
off flavors, colors, and aromas in hundreds of other foods and
beverages and decreases shelf life. Now, researchers in Italy report
development of a more reliable method for predicting shelf-life that
accounts for light sensitivity for the first time and may help
consumers choose fresher, tastier food products. Their study is
scheduled for the June 25 issue of ACS' Journal of Agricultural and
Food Chemistry, a bi-weekly publication.
In the new study, Lara Manzocco and colleagues note
that the bright, intense light of retail displays is widely known to
cause the formation of off-flavors, loss of nutrients, and color
fading in food and beverages. But conventional methods to test the
shelf-life of these products focus on the effect of heat and ignore
the effect of light, leading to underestimations in shelf-life shown
on product expiration labels. A more reliable test is needed, the
researchers say.
The scientists exposed a soft drink containing
saffron, which contains light-sensitive substances, to different
levels of light at increasing temperatures. They found that the
beverage grew lighter in color as light intensity increased,
confirming that light can cause a dramatic decrease in beverage
quality. Based on these observations, the scientists developed a new
mathematical model that measures light-sensitivity as well as
temperature to provide a more reliable method for predicting
shelf-life. - MTS
New research reports that 12 million molecules
share 143 basic shapes
Chemists in Ohio have discovered that half of all
of the known chemical compounds in the world have an amazing
similarity in sharing only 143 basic molecular shapes. That sharply
limits the number of molecular building blocks that chemists often
deploy in efforts to develop new drugs and other products, the
researchers say in a study scheduled for the June 20 issue of the
bi-weekly ACS' Journal of Organic Chemistry.
Alan H. Lipkus and colleagues note that researchers
have known for years that certain features of molecules, such as rings
of atoms and the bonds than link them together, appear time after time
in hundreds of life-saving medications, food additives, and other
widely used products.
Scientists often tend to focus on these well-known
types of molecular scaffolding in their quest to select the most
promising rings, linkers, and other components for building new drugs
while overlooking less familiar structures, the researchers say.
In the new study, they analyzed the chemical
frameworks of more than 24 million organic substances found in the ACS'
Chemical Abstracts Service (CAS) Registry, the world's most
comprehensive database of disclosed molecules. They found that half of
the substances could be described by only 143 basic framework shapes.
By paying more attention to a multitude of other molecular shapes,
chemists might discover an array of useful rings, linkers, and other
building blocks for tomorrow's drugs and other medical, commercial,
and industrial products, the study concluded. - MTS
Building giant 'nanoassemblies' that sense their
environment
An optical photograph reveals
self-assembly of hybrid nanowires resulting in this golden droplet.
Such structures could help develop nanomachines for the medical
community, scientists report.
Image by Pulickel M. Ajayan
Researchers in Texas are reporting the design,
construction, and assembly of nano-size building blocks into the first
giant structures that can sense and respond to changes in
environmental conditions. The study, scheduled for the July 9 issue of
ACS's Nano Letters, a monthly journal, terms those structures "giant"
because they are about the size of a grain of rice - millions of times
larger than anything in the submicroscopic realm of the nanoworld.
In the new study, Pulickel M. Ajayan and colleagues
point out that such structures are a step toward the development of
futuristic nanomachines with practical applications in delivering
medicines to patients, labs-on-a-chip, and other products. Until now,
scientists have had difficulty in using nanomaterials to build more
complex, multifunctional objects needed for those applications.
The researchers describe development of a hybrid
nanowire consisting of segments with water-repelling carbon nanotubes
on one end and water-attracting metal nanowires on the other end. In
laboratory tests, they showed that the nanowires could assemble
themselves into larger, more complex structures when placed in water.
The structures also sensed and responded to their environment by
making movements when exposed to chemicals, magnets, and light. The
findings "could lead to the creation of smart materials that are a
cornerstone for the development of nanotechnology-based applications,"
the study notes.
From carrots to grapefruits to tortillas,
researchers worldwide are giving common foods a more nutritious
makeover by removing unhealthy substances and adding or enhancing
those that may help fight diseases such as cancer and heart disease,
according to an article scheduled for the June 23 issue of Chemical &
Engineering News. Some of these products could soon appear at a
grocery store near you.
In the C&EN cover story, Associate Editor Rachel
Petkewich points out that, amid growing consumer interest in leading a
healthier lifestyle, scientists are identifying an increasing number
of disease-fighting substances in foods and using them to enhance food
crops. As evidence for this skyrocketing interest in healthier foods,
the article notes that the number of published papers exploring the
disease-fighting properties of food components has quintupled since
2003. Scientists have already developed carrots with super-high
antioxidant levels. Other foods designed to target cancer, high
cholesterol, and other health conditions may soon be on the way.
But creating healthier foods that are still
appealing to consumer taste can be tricky, as changing certain food
components makes flavor and texture unappetizing. Scientists are now
working on creating substances that can boost nutrition without
loosing the qualities consumers find appealing.
Lake sediments help scientists trace 7,000 years
of mining, metal use in China
Scientists used core sediments
from China's Liangzhi Lake to track use of metals over several
thousand years.
Image by Xiangdong Li
A new geochemical study illuminates 7,000 years of
mining and metal use in central China and links these trends to
fluctuations in airborne pollution during the Bronze Age and other
military and industrial periods in Chinese history. The study, which
could help scientists better assess the accumulative environmental
effects of human activity in the region since prehistory times, is
scheduled for the July 1 issue of the ACS' Environmental Science &
Technology, a semi-monthly journal.
Using carbon-dated core sediments taken from
Liangzhi Lake in Hubei province, Xiang-Dong Li and colleagues were
able to track metal deposit trends at the lake dating back to 5,000 B.
C. Liangzhi Lake, located in an important region in the development of
Chinese civilization, is relatively undistributed by local wastewater
discharges and is therefore an ideal site to study ecological changes
and the effects of past human activity, the scientists say.
Beginning in about 3,000 B.C. concentrations of
copper, nickel, lead and zinc in the sediments began to rise,
indicating the onset of Bronze Age in ancient China, the researchers
found. In the late Bronze Age (475 B.C. to 220 A.D.), an era
corresponding with numerous wars, sediment concentrations of copper
increased 36 percent and lead by 82 percent. Copper and lead were used
extensively to make bronze tools and weapons. The sediments suggest
mining and metal usage in the region continued to wax and wane into
the modern era, reflecting the environmental changes influenced by
past human activity. - DMD
Scientists report that the simple
inhalation of coffee by rats has changed their gene expressions in
ways that help reduce sleep deprivation-induced stress.
Credit: public-domain-photos.com
Drink coffee to send a wake-up call to the brain?
Or just smell its rich, warm aroma? An international group of
scientists is reporting some of the first evidence that simply
inhaling coffee aroma alters the activity of genes in the brain. In
experiments with laboratory rats, they found that coffee aroma
orchestrates the expression of more than a dozen genes and some
changes in protein expressions, in ways that help reduce the stress of
sleep deprivation. Their study is scheduled for the June 25 issue of
ACS' bi-weekly Journal of Agricultural and Food Chemistry.
Han-Seok Seo and colleagues point out that hundreds
of studies have been done on the ingredients in coffee, including
substances linked to beneficial health effects. "There are few studies
that deal with the beneficial effects of coffee aroma," they note. "This
study is the first effort to elucidate the effects of coffee bean
aroma on the sleep deprivation-induced stress in the rat brain."
In an effort to begin filling that gap, they
allowed lab rats to inhale coffee aroma, including some rats stressed
by sleep deprivation. The study then compared gene and protein
expressions in the rats' brains. Rats that sniffed coffee showed
different levels of activity in 17 genes. Thirteen of the genes showed
differential mRNA expression between the stress group and the stress
with coffee group, including proteins with healthful antioxidant
activity known to protect nerve cells from stress-related damage. -
MTS
Natural plant materials to regulate starch
digestion
Researchers in Switzerland are reporting discovery
of natural plant materials that may regulate starch digestion -
slowing down the body's conversion of potatoes, rice, and other
carbohydrate-rich foods into sugar. The findings could lead to new
functional foods that fight diabetes, they say in a report scheduled
for the June 26 issue of the ACS' bi-weekly Journal of Medicinal
Chemistry.
In the new study, Elena Lo Piparo and colleagues
explain that a key digestive protein called alpha-amylase rapidly
converts certain high-carb foods into glucose or blood sugar. That
fast conversion results in sudden spikes in blood sugar in patients
with diabetes. A common clinical strategy to manage sharp rises in
blood glucose after eating is the use of pharmaceutical agents that
inhibit specific starch-splitting enzymes. Although researchers have
known for years that some natural foods appear to contain chemicals
capable of blocking alpha-amylase, the exact structure and mechanism
of action of these substances remained unknown.
The researchers at Nestl� Research Center were
interested in finding natural food-based compounds that can modulate
this process, and to further understand the molecular mechanisms
through which this interaction occurs. Using molecular modeling
techniques they selected 19 plant components, called flavonoids, to be
tested for their ability to block alpha-amylase activity. They
identified 7 flavonoids with significant inhibition of alpha-amylase,
the strongest of which inhibited activity by 99 percent. Knowledge
gained from this study will lead to a better understanding about
food-based compounds and their natural properties, to help the
research and development of products with a positive impact on health
and wellness. - MTS
Coats of cellulose from bacteria yield greener,
stronger natural composites
Researchers report a new method
of depositing bacterial cellulose on plant fibers to enhance
durability and strength of composite materials.
Image by The American Chemical
Society
Researchers in the United Kingdom report the first
use of bacteria to deposit sticky coatings of cellulose on the
surfaces of plant fibers, a process that may expand the use of natural
fibers in renewable plastic composites used as strong, lightweight
materials for cars, airplanes, and other products. The coated fibers
provide strength and will make composites more durable without
affecting their biodegradability. They are more suitable for recycling
(or compositing) than commonly used petroleum-based composites, the
researchers say. Their study is scheduled for the June issue of ACS'
Biomacromolecules, a monthly journal.
In the new study, Alexander Bismarck and colleagues
point out that synthetic composite materials now in use are made from
nonrenewable, petroleum sources which are becoming more expensive.
These materials not only are difficult to break down, they also create
environmental hazards when disposed. Existing composites made from
natural fibers show poor adhesion qualities and must be strengthened
by using other synthetic coupling agents, some of which are toxic, the
researchers note.
The researchers coated hemp and sisal fibers with
nano-sized particles of bacterial cellulose through a special
fermentation process. The coated sisal fibers showed much better
adhesion properties than the original fibers without losing their
mechanical properties, ideal properties for their use in composites,
the researchers say. The modified hemp fibers also had improved
adhesion properties but showed a loss of strength, they note. - MTS
Increasingly potent drug ingredients offer
growing market as manufacturers address worker safety
To develop improved drugs for fighting cancer and
other diseases, pharmaceutical researchers are finding increasingly
potent drug ingredients that will allow smaller doses while causing
fewer side effects, according to an article scheduled for the June 16
issue of Chemical & Engineering News. This development has also
spawned efforts by pharmaceutical ingredient manufacturers to increase
production, while assuring the safety of workers in their plants who
might be exposed to these powerful new chemicals.
In the C&EN cover story, Senior Correspondent Ann
Thayer points out that these powerful agents are part of the rapidly
expanding anticancer drug market, which racks up $48 billion in sales
each year and is growing at twice the rate of the overall
pharmaceutical market. These substances include targeted drugs, which
zero in on disease tissues and cells rather than exposing the entire
body to any harmful effects.
The growth in demand for these potent drug
ingredients is contributing to an increase in the number of
manufacturers that specialize in making them. As a result,
pharmaceutical manufacturers are building new facilities that can
operate at higher and safer levels of containment and are adding
specialized equipment to protect workers from exposure to these potent
materials, the article notes.
"Super paper:" New nanopaper more
break-resistant than cast iron
Scientists report development of
cellulose nanopaper, a superstrong material that could be used in
the construction industry. Above is a cross-section of a fracture
surface of a cellulose nanofibril film.
Image by the American Chemical
Society
Researchers in Sweden and Japan report development
of a new type of paper that resists breaking when pulled almost as
well as cast iron. The new material, called "cellulose nanopaper," is
made of sub-microscopic particles of cellulose and may open the way
for expanded use of paper as a construction material and in other
applications, they suggest. Their study is scheduled for the June 9
issue of ACS' Biomacromolecules, a monthly journal.
In the new study, Lars A. Berglund and colleagues
note that cellulose - a tough, widely available substance obtained
from plants - has potential as a strong, lightweight ingredient in
composites and other materials in a wide range of products. Although
cellulose-based composites have high strength, existing materials are
brittle and snap easily when pulled.
The study described a solution to this problem. It
involves exposing wood pulp to certain chemicals to produce cellulose
nanopaper. Their study found that its tensile strength - a material's
ability to resist pull before snapping - exceeded that of cast iron.
They also were able to adjust the paper's strength by changing its
internal structure. - MTS
Sniffing out a broad-spectrum of airborne threats
in seconds
Scientists in California are reporting successful
laboratory and field tests of a new device that can sniff out the
faintest traces of a wide range of chemical, biological, nuclear, and
explosive threats - and illicit drugs - from the air in minutes with
great accuracy. The ultra-sensitive detector, known as the
single-particle aerosol mass spectrometry (SPAMS) system, could
tighten security at airports, sports stadiums and other large-scale
facilities, according to their report, scheduled for the July 1 issue
of ACS' Analytical Chemistry, a semi-monthly journal.
Matthias Frank and colleagues explain that chemical,
biological, nuclear, and explosive materials, as well as illicit drugs,
all release minute amounts of aerosol particles into the air.
Detecting these particles requires a device with a high sensitivity,
low probability of false alarms, and a fast response time. "SPAMS
uniquely meets these requirements in realistic field environments,"
the report states. While other aerosol detectors exist, SPAMS is
specifically designed for the rapid detection of low-concentration
aerosols, it adds.
The study describes laboratory tests of SPAMS and
extended field tests at San Francisco International Airport. It showed
that within seconds, SPAMS detected a diverse set of materials
including simulants for potentially hazardous biological, chemical and
radiological materials, as well as actual explosives and drugs. The
study terms SPAMS a "significant and important advance in rapid
aerosol threat detection." - AD
Inhalable form of gene-therapy takes aim at lung
cancer and inflammatory lung disease
A new inhalable form of gene therapy - based on
technology recognized in the 2006 Nobel medicine prize, shows
increasing promise for treating lung cancer, infectious diseases and
inflammatory lung disease, scientists have concluded after an
exhaustive review of worldwide research on the topic. Their report is
scheduled for the June 2 issue of ACS' Molecular Pharmaceutics, a
bi-monthly journal.
In the article, Sally-Ann Cryan, Niamh Durcan, and
Charlotte Murphy focus on research efforts to develop an inhalable
form of RNA interference (RNAi), a gene-therapy technique that
interferes with or "silences" genes that make disease-causing proteins.
The authors explain that RNAi has advantages over other gene therapies.
It is potent, very specific, and appears to have a low risk of side
effects.
They cite encouraging results with RNAi in
laboratory studies in cells and animals with a range of lung diseases,
including lung cancer, certain respiratory infections and inflammatory
lung disease. Keys to successful therapy in humans include careful
design of the gene-silencing agents, determining the most effective
doses, and developing better ways of delivering RNAi agents to the
lungs, the scientists say. - MTS
Researchers band together in global battle on
bacterial biofilms
The discovery that bacteria are not loners, but
social creatures that congregate and chemically communicate in
communities - termed biofilms - has sparked a global scientific effort
to control spread of these slimy coatings that grow on hospital
surfaces, inside tubing, and a multitude of other places. That's the
topic of an article scheduled for the June 9 issue of Chemical &
Engineering News, ACS' weekly newsmagazine.
In the C&EN cover story, Senior Editor Lisa M.
Jarvis points that biofilms are the major culprit behind
hospital-acquired infections that are now the fourth leading cause of
death in the United States, claiming thousands of lives each year.
Biofilms also cause other problems ranging from dental plaque to the
biofouling of ship hulls. The films are large, complex communities of
bacteria that are difficult to kill.
But researchers from academia and industry are now
collaborating in a global effort to develop promising new strategies
to combat this problem. New approaches include the development of
non-stick surfaces and the identification of chemicals that silence
bacterial communication or starve them of key nutrients. The first
commercial compound to specifically target biofilms is still a few
years away, according to the article.
Love that garlic? Fresh may be healthier than
bottled
Compared to bottled garlic, fresh
garlic contains higher levels of an ingredient called allicin,
which can help prevent blood clots and bacterial infections.
Image by Bruce Fritz
The next time you use garlic for its renowned
antibacterial effects, consider fresh garlic instead of those bottles
of chopped garlic. Researchers in Japan report that fresh garlic
maintains higher levels of a key healthy ingredient than preserved
versions and may be better for you. Their study is scheduled for the
June 25 issue of ACS' Journal of Agricultural and Food Chemistry, a
bi-weekly publication.
In the new study, Toyohiko Ariga and colleagues
point out that allicin is one of the main active ingredients in garlic.
Other studies have shown that allicin has beneficial effects in
preventing blood clots, cancer, and bacterial infection. Although
commercially bottled garlic is often stored in oil or water,
researchers did not know how various storage and preservation methods
affect levels of allicin, which is fragile and disappears quickly.
To find out, Ariga's group compared allicin levels
in extracts of fresh garlic after 1-2 weeks of storage in water,
alcohol, and vegetable oil. Garlic stored in water at room temperature
lost about half its allicin in 6 days and garlic in vegetable oil lost
half its allicin in less than an hour. The garlic lost its
antibacterial action as allicin broke down. However, allicin broke
down into materials that still are believed to have some anticancer
and anti-blood clot effects. - MTS
Lead leaching and faucet corrosion in PVC home
plumbing
Plumbing systems with polyvinyl
chloride plastic pipes could be more susceptible than copper pipes
to leaching of lead and copper into drinking water, researchers
report.
Image by Marc Edwards
Scientists in Virginia are reporting that home
plumbing systems constructed with polyvinyl chloride (PVC) plastic
pipes may be more susceptible to leaching of lead and copper into
drinking water than other types of piping - especially when PVC
systems include brass fixtures and pipefittings. The study is
scheduled for the June 15 issue of ACS� Environmental Science &
Technology, a semi-monthly journal.
Marc Edwards and colleagues point out that more
water purification plants in the United States are using chloramine to
treat water. At the same time, builders are plumbing more houses with
plastic pipe, rather than copper, to cut costs. Past studies have
found that ammonia formed in chloramine-treated water can trigger a
series of events that corrode brass faucet components and connectors
commonly used in PVC plumbing systems. Corrosion of brass (made with
copper, zinc and lead) releases those metals into water pipes and
makes faucets prone to failure.
In the new study, researchers sampled water from
polyvinyl chloride (PVC), copper, lead, and other pipe material under
a range of experimental conditions. They found that corrosive
conditions were often worst in plastic pipes, which could be expected
to cause higher metal leaching of zinc and lead from brass faucets
used in homes and buildings. - AD
Researchers have identified
alpha-carbonyls as important compounds that reduce beer's flavor.
Image by public-domain-photos.com
Scientists in Venezuela are reporting an advance in
the centuries-old effort to preserve the fresh taste that beer
drinkers value more than any other characteristic of that popular
beverage. Their study, which identifies key substances involved in
giving beer an aged or "oxidized" flavor, is scheduled for the May 28
issue of ACS� Journal of Agricultural and Food Chemistry, a bi-weekly
publication.
In the new study, Adriana Bravo and colleagues
point out that past efforts to keep beer fresh have focused on
protecting beer from contact with the air throughout the brewing
process. That focus, however, has resulted in only a relatively small
improvement in flavor stability.
The research identified a group of poorly
understood substances called alpha-carbonyls as important culprits in
the decline in fresh flavor that occurs as beer ages. It also showed
that levels of some of these substances could be reduced by adding
ingredients that block their formation, thus making beer taste fresher
longer. - MTS
Mother Nature�s antibacterial dyes: Bright colors
and a knockout punch for germs
A strain of marine bacteria produces large amounts
of bright red pigments that can be used as a natural dye for wool,
nylon, silk and other fabrics, scientists in California are reporting.
The dyes from Mother Nature�s palate also have an anti-bacterial
effect that could discourage harmful bacteria from growing on socks,
undergarments, and other clothing, they report in a study scheduled
for the June 6 issue of ACS� Biotechnology Progress, a bi-monthly
journal.
In the new research, graduate student Farzaneh
Alihosseini, her adviser Gang Sun and colleagues point out that
conventional dyes and pigments used in clothing have several drawbacks.
Many are made from non-renewable resources such as petroleum, and are
potentially harmful to the environment and human health. In addition,
concerns exist about the potential toxicity of existing
antibacterial-fabric coatings.
The researchers found that a certain strain of
bacteria isolated from marine sediments produces large quantities of
bright red pigments called prodiginines that can be used to dye
clothing. In laboratory tests, the pigments worked on wool, silk,
nylon, and acrylic fabrics as efficiently and effectively as some
conventional dyes. The pigments showed strong antibacterial activity
against harmful bacteria, including E. coli and Staphylococcus aureus,
when applied to most of the fabrics tested. - MTS
Nano-tech process produces plastics that are 10
times more stretchable
Scientists report development of
a plastic that is 10 times more stretchable than that of the
original material. Above is a micrograph of the electrospun
nano-sized fibers.
Image by The American Chemical
Society
Move over, Rumplestiltskin. Researchers in China
report the first successful �electrospinning� of a type of plastic
widely used in automobiles and electronics. The high-tech process,
which uses an electric charge to turn polymers into thin fibers in the
presence of electricity, produced plastic mats that can stretch 10
times more without breaking than the original material and could lead
to new uses for the plastic, they say. Their study is scheduled for
the June 10 issue of ACS� Macromolecules, a bi-weekly journal.
In the new study, Zhao-Xia Guo and colleagues point
out that the original plastic, called polyoxymethylene (POM), is an
engineering staple known for its metal-like hardness, light weight,
and resistance to chemicals. However, the material is relatively
brittle, limiting its applications. Although many different types of
plastics have been electrospun into fibers with extended uses and
properties, researchers have been unable to spin POM into fibers until
now, the researchers say.
They report that POM could be turned into
nano-sized fibers - thousands of times thinner than the width of a
single hair - after first dissolving it in a solution called HFIP and
then undergoing electrospinning. The process resulted in POM mats with
improved stretchability, or ductility, high porosity, and high surface
area. Such features could extend the plastic�s uses to a wide range of
industrial, electronic and medical applications, the researchers say.
- MTS
Bisphenol A: Controversy over widely used plastics
chemical spurs product changes, regulatory debate
The controversy over bisphenol A (BPA) is spurring
manufacturers to offer BPA-free products and fueling debate over how
new chemicals enter the market, according to an article scheduled for
the June 2 issue of Chemical & Engineering News, ACS� weekly
newsmagazine. Widely used in consumer products, including baby bottles
and beverage bottles, BPA has come under increasing scrutiny by
Congress, regulators in the U.S. and abroad, the news media, and other
groups over its allegedly harmful health effects.
Written by C&EN Associate Editor Britt Erickson,
the story points out that retailers and manufacturers alike are not
waiting for scientists to settle the unknowns about BPA, which can
have estrogen-like biological effects. Instead, they have been pulling
BPA products from store shelves or abandoning its use altogether.
Consumers also are avoiding products packaged in containers made with
BPA.
More than two billion pounds of BPA are used
annually in the United States. Although a growing number of studies
suggest that low-level exposure to the chemical can cause cancer,
obesity, and other health problems, the plastics industry and federal
regulatory agencies insist that the chemical is safe, the article
states. Erickson described how Congress entered the fray by launching
an investigation into the use of BPA in baby bottles.
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