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09-May-2007
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Fluorescent
nanoparticles serve as flashlights in living cells
By using fluorescent 'quantum dot' nanoparticles, scientists of the
University of Twente are able to combine two optical techniques
-fluorescence and Raman microscopy- for better understanding of the
processes in a single living cell.
•
E-Hopping
New '1/f noise' discovery promises to improve semiconductor-based
sensors.
Exposure to depleted uranium from military action
may pose health threats
Exposure to particles of depleted uranium (DU), the
source of growing international concern as a potential health hazard,
may increase the risk of genetic damage and lung cancer, scientists in
Maine conclude in a report scheduled for the May 21 issue of ACS'
Chemical Research in Toxicology, a monthly journal.
DU is the material remaining after removal or
depletion of the U-238 isotope of uranium. With a density about twice
that of lead, DU is ideal for use in military armor and munitions,
John Pierce Wise, Sr., and colleagues point out in the new study. DU
dust produced in combat creates potentially frequent and widespread
exposure for soldiers and non-combatants, who may inhale DU dust
particles, the researchers note.
However, there have been few studies on the health
effects of lung exposure to DU, they add. In the new study,
researchers tested the effects of DU on cultures of human lung cells.
"This is the first article on the cytotoxicity and clastogenicity [chromosome
damaging potential] of particulate and soluble DU in human bronchial
cells," the study states. "These data suggest that exposure to
particulate DU may pose a significant genotoxic risk and could
possibly result in lung cancer."
New process boosts levels of heart-healthy
compounds in cocoa powder
Scientists in Spain are reporting development of a
new process to make cocoa powder with higher amounts of the healthful
chemical compounds linked to chocolate's beneficial effects. The study
is scheduled for publication in the May 30 issue of ACS' Journal of
Agricultural and Food Chemistry.
Juan Carlos Espin de Gea and colleagues report that
the new cocoa powder contains levels of some flavonoids 8 times higher
than conventional cocoa. They achieved the higher flavonoid content by
omitting the traditional fermentation and roasting steps used in the
processing of cocoa beans. Those steps destroy some flavonoids, which
are natural antioxidants.
Researchers used the flavonoid-enriched cocoa
powder in a clinical trial to determine whether the compounds were
bioavailable - in a form that humans can absorb. In the trial, six
healthy volunteers consumed a milk drink made with flavonoid-enriched
cocoa. The same volunteers later drank chocolate milk made from
traditional cocoa. Blood and urine tests established the
bioavailability of flavonoids in the enriched-milk drink, showing that
people do absorb higher levels of the compounds. Based on the results,
researchers suggest further clinical trials on the health benefits of
flavonoid-enriched cocoa powder.
Skin patch tests may miss patients allergic to
common fragrance
Skin patch screening test for allergy to fragrances
— second only to nickel as the most common cause of contact dermatitis
in the Western world — may not detect some cases of allergy to a
widely used fragrance chemical, Swedish scientists are reporting.
In a study scheduled for publication May 8 in ACS'
Chemical Research in Toxicology, Ann-Therese Karlberg and
colleagues focus on geraniol, a chemical in Fragrance Mix I (used for
allergy skin patch testing). Because of its fresh, floral scent,
geraniol is widely used in household products, underarm deodorants and
cosmetics, the report states. Geraniol has been regarded as a weak
allergen, responsible for only about 5 percent of positive patch test
responses to the fragrance allergens used for screening of fragrance
allergy in dermatitis patients.
The new research, however, shows that geraniol
oxidizes during exposure to air, changing into a more potent allergen.
"Cases of allergy to the oxidation products of geraniol will not be
diagnosed unless patients are tested with the air-exposed material,"
the report states. "Thus, our observations once more emphasize the
need for testing with the right material for screening contact allergy."
New antifreeze protein gives cold shoulder to its
natural counterpart
In another illustration of chemistry's knack for
improving on Mother Nature, scientists in Canada and the United States
are reporting that a synthetic version of a natural antifreeze protein
— with numerous potential applications — is far superior to the
natural product. The study is scheduled for publication in the May 14
issue of ACS' Biomacromolecules, a monthly journal.
The University of Ottawa's Robert N. Ben and
colleagues report on a synthetic version of the antifreeze
glycoproteins (AFGPs) that enable Arctic and Antarctic fish to survive
in freezing-cold waters. AFGPs, they note, have applications ranging
from prevention of freezer burn in frozen foods to preservation of
human organs donated for transplantation. Barriers to those uses
include the scarcity and high cost of natural AFGPs.
In the new study, researchers found that their
artificial AFGP, which can be produced in large quantities, also
appears safer in laboratory cell culture tests. A natural AFGP caused
cell damage that could substantially limit its use as an organ
preservative, for instance, while the synthetic compound showed no
such toxicity. The researchers term their results "exciting," and
describe the synthetic AFGP as "an extremely valuable lead compound
for the development of novel cryoprotectants."
"Venture philanthropists" fill a gap in funding
early stages of drug discovery
With traditional venture capital firms shying away
from investments that traditionally sustained the early stages in drug
discovery among biotechnology start-up firms, "venture philanthropists"
have quietly stepped up to fill the gap, according to an article
scheduled for the May 2 issue of Chemical & Engineering News (C&EN)
ACS' weekly newsmagazine.
In the article, C&EN associate editor Lisa
Jarvis describes how venture capital firms have shifted away from
investment in early-stage drug development, which provides "seed money"
for start-up firms to begin work on promising new drugs. Those firms
now are putting cash into the later stages of drug development and
commercialization, where risks are smaller and marketable products are
more likely to result.
The shift in priorities has resulted in emergence
of the venture philanthropy movement,in which non-profit organizations,
such as the Cystic Fibrosis Foundation, have become an important
source of money for early-stage drug discovery. At that stage,
academic scientists, entrepreneurs and start-up companies are seeking
money for research to validate ideas for new drugs. Jarvis surveys the
venture philanthropy landscape, and explains how disease advocacy
groups have become major players in the for-profit world of biotech
startups.
A research team led by Neal Woodbury, a scientist
at ASU's Biodesign Institute, has come up with a new insight into the
mechanism of photosynthesis, which involves the orchestrated movement
of proteins on the timescale of a millionth of a millionth of a
second.
Their findings are described in "Protein Dynamics
Control the Kinetics of Initial Electron Transfer in Photosynthesis,"
in the May 4 issue of Science.
Technique monitors thousands
of molecules simultaneously
A chemist is making molecules the new-fashioned way - selectively
harnessing thousands of minuscule electrodes on a tiny computer chip
that do chemical reactions and yield molecules that bind to receptor
sites.
Laser-trapping of rare element
gets unexpected assist
researchers have successfully laser-cooled and trapped atoms of radium
- the first time this rare element has been captured in a
magneto-optical trap - with an assist from an unexpected source.
Georgia Tech physicists have
discovered that water behaves differently when its compressed in
nano-sized channel. In these small spaces water behaves much like
a solid, exhibiting high viscosity and organizing itself into
layers.
Nanotechnology
provides 'green' path to environmentally sustainable economy
A new report explores potentially beneficial links between
nanotechnology and green chemistry and engineering, which aim to
minimize environmental impacts through resource-conserving and
waste-eliminating improvements in processes and products.
A
fascinating new study from the May/June 2007 issue of Physiological
and Biochemical Zoology quantifiably measures the loss of strength and
endurance in black bears during long periods of hibernation.
PFOA and PFOS
detected in newborns
An analysis of nearly 300 umbilical cord blood samples shows that
newborn babies are exposed to perfluorooctane sulfonate (PFOS) and
perfluorooctanoate (PFOA) while in the womb.
•
Class of PCB's causes developmental
abnormalities in rat pups
Scientists have determined that a specific class of PCB causes
significant developmental abnormalities in rat pups whose mothers were
exposed to the toxicant in their food during pregnancy and during the
early weeks when the pups were nursing.
•
More nutritious, less
toxic
High-quality food helps reduce toxins in the food chain, Dartmouth-led
research finds.
•
How much nitrogen is too much
for corn?
Growers could cut back on fertilizer and reap economic and
environmental benefits by using a rapid test recently discovered by
scientists to accurately predict nitrogen levels.
A human body has more than 10 to the power of 27
molecules with about one hundred thousand different shapes and
functions. Interactions between molecules determine our structure and
keep us alive. Researchers have followed the interaction of only
two individual molecules to show the basic mechanism underlying
recognition of dipeptides.
New treatment yields complete regression of a
human cancer in mice
A simple modification in an anti-cancer treatment
currently in clinical trials substantially improves the drug’s
effectiveness and reduces side effects in experiments with laboratory
mice, researchers are reporting in an article scheduled for the May 16
edition of ACS’ Bioconjugate Chemistry, a bi-monthly journal.
Enzon Pharmaceuticals’ David Filpula and colleagues at the National
Cancer Institute worked on SS1P, a so-called immunotoxin that targets
and destroys cells producing the surface protein mesothelin.
Ovarian, pancreatic and malignant mesothelioma
cells all produce abnormally large amounts of mesothelin and thus are
targets for SS1P. In the new study, researchers modified SS1P with
PEGylation, which involves attaching chains of polyethylene glycol
(also known as PEG) to the molecule. PEGylation is a well-established
process that is used in at least six protein-based pharmaceutical
products currently on the market.
PEGylated SS1Ps had fewer side effects and were
more effective in mice bearing human tumors than standard SS1P, the
report states. A single dose of the modified SS1P resulted in complete
regression of the mouse tumors, the first time that such an effect had
been observed, the researchers said. PEGylation of SS1P and other
immunotoxins may hold promise for use in cancer patients, as well,
they added.
Synthetic fuels from alternative energy sources
can power the U. S. military
The U.S. military, searching for a synthetic
alternative to imported petroleum-based fuel, can power its 21st
Century vehicles with the same chemical technology Germany used to
produce its gasoline during World War II, according to a study
scheduled for the May 16 issue of ACS’ Energy and Fuels, a
bi-monthly journal.
In the study, Sasol Technology’s Delanie Lamprecht
points out that the U.S. Department of Defense (DoD) has been seeking
alternative ways of obtaining "Jet Propulsion 8" (JP-8). DoD uses that
single kerosene-type fuel, virtually identical to commercial aviation
fuel, for almost all its gas turbine and tactical diesel engine
applications. The defense department also wants an alternative route
to JP-5, a slightly different fuel used on aircraft carriers.
Invited to participate in the effort to develop
alternatives, Lamprecht studied use of so-called Fischer-Tropsch
technology. Sasol is a pioneer in use of the technology to produce
synthetic fuels from coal. It can convert coal, natural gas, or
biomass into a synthesis gas and thereafter into a Fischer-Tropsch
syncrude suitable for refining into JP-8, JP-5 and other liquid fuels.
The study concluded that it is feasible to use the process, together
with current refining technology, to produce a "battlefield fuel of
the future" that could power the military without reliance on imported
oil.
Scientists in the United States and Canada are
reporting the first scientific evidence that ancient civilizations in
the Central Andes Mountains of Peru smelted metals, and hints that a
tax imposed on local people by ancient Inca rulers forced a switch
from production of copper to silver. Their study is scheduled for the
May 15 issue of ACS’ Environmental Science & Technology, a
semi-monthly journal.
The University of Alberta’s Colin A. Cooke and
colleagues point out that past evidence for metal smelting, which
involves heating ore to extract pure metal, was limited mainly to the
existence of metal artifacts dating to about 1,000 A.D. and the Wari
Empire that preceded the Inca. The new evidence emerged from a study
of metallurgical air pollutants released from ancient furnaces during
the smelting process and deposited in lake sediments in the area.
By analyzing metals in the sediments, the
researchers recreated a 1,000-year history of metal smelting in the
area, predating Francisco Pizarro and his Spanish conquistadors by 600
years. Their findings show that smelters in the Morococha region of
Peru switched from production of copper to silver around the time that
Inca rulers imposed a tax, payable in silver, on local populations.
Calorie restriction and increased longevity
linked to metabolic changes
In a study of Labrador retriever dogs, those fed a
calorie-restricted diet showed different lifelong patterns relating to
energy metabolism and the activities of their gut microbes and lived
almost two years longer than similar dogs given a slightly
higher-calorie diet. The study, which followed 24 dogs lifelong, is
scheduled for the May 4 issue of ACS’ Journal of Proteome Research,
a monthly publication.
Imperial College London’s Jeremy K. Nicholson and
colleagues from Nestlé and Nestlé Purina Research centers in
Switzerland and the United States point out that previous studies on a
range of animals have established calorie restriction as a proven
method for extending the lifespan of animals. Those studies, however,
have not explained how calorie restriction works.
The new study aimed at improving knowledge of the
metabolic effects of caloric restriction suggests that some of the
important beneficial changes may relate to the activities of the
symbiotic bacteria that live in the intestinal tract. Those microbes
produce a range of biochemicals that may influence disease processes
and alter energy metabolism in the host organism. Researchers paired
24 dogs, with one dog in each pair given 25 percent less food than the
other. Those with a restricted intake of calories lived, on average,
about 1.8 years longer than those with a greater intake. Researchers
noted that the study’s main goal was to help develop diets that keep
pet animals alive and healthy for as long as possible, but that the
findings may be relevant to human dietary changes and obesity.
New water filtration materials help assure safe
drinking water
A new generation of water filtration materials is
enabling municipalities and industries in the United States and
water-short countries overseas to produce safe drinking water from
supplies contaminated with salts and other undesirable compounds,
according to an article scheduled for the April 23 issue of
Chemical & Engineering News, ACS’ weekly newsmagazine.
In the article, C&EN senior editor Marc S.
Reisch explains that the technology — termed membrane filtration —
also removes bacteria and chlorine-resistant parasites such as
Cryptosporidium and Giardia. Starting with highly
contaminated water, membrane filtration can produce potable water that
can be purer than water from pristine reservoirs or deep artesian
wells, the article notes.
Reisch describes a growing market for membrane
filtration in Florida, Texas, California and other locales that must
treat brackish water. Much of the demand in the United States results
from increasingly stringent Federal regulations for drinking water
drawn from surface sources. Demand for the technology also is strong
abroad, especially in areas such as the Middle East that face severe
water shortages and produce drinking water by desalination of sea
water. A related C&EN story focuses on global chemical industry
efforts to make safe, secure sources of drinking water more widely
available.
Chemical & Engineering News: "Filtering out
the bad stuff: Polymeric membranes are increasingly being used to
clean up water for drinking and industrial use":
Scientists design new super-hard
material
UCLA scientists are now reporting a promising new approach to
designing super-hard materials, which are very difficult to scratch or
crack.
Physicists tweak zinc to get many model compounds.
Try as they might, ancient alchemists could never turn
lead into gold. Neither can the members of the Novel Materials group
at the U.S. Department of Energy's Ames Laboratory. But these
physicists do have a way with materials, and they can get them to do
some pretty amazing things ...
•
Scent prediction
Lily of the valley fragrance: Electronic surface structure determines
interactions with scent receptors.
Ethanol vehicles pose a
significant risk to human health, study finds
Ethanol is widely touted as an eco-friendly, clean-burning fuel. But
if every vehicle in the United States ran on fuel made primarily from
ethanol instead of pure gasoline, the number of respiratory-related
deaths and hospitalizations would likely increase ...
A new test to screen fish for 25 drug residues
at the same time
Amid growing concern about the accumulation of
pharmaceutical and personal care products (PPCPs) in fish and other
aquatic organisms, scientists in Texas are reporting development of
the first method that can screen fish for several different groups of
drugs at the same time. The research is scheduled for publication in
the April 15 edition of ACS’ Analytical Chemistry, a
semi-monthly journal.
In the report, C. Kevin Chambliss and colleagues
note that previous tests for detecting PPCPs in water, sediment and
other environmental material could identify only individual
medications or classes of medications, such as antibiotics. And there
were just a few methods for measuring certain drug residues in fish
tissue.
"We report the first multi-residue screening method
for pharmaceuticals representing multiple therapeutic classes in fish
tissue," the report states. It involves a way of preparing samples
that is simpler and less-time consuming than existing methods and can
simultaneously monitor fish for 25 drugs.
The researchers describe use of the method to
identify drug residues in fish from the sunfish family (which includes
popular pan fish such as bluegills) in a Texas creek composed almost
entirely of effluent from a sewage treatment plant. The drugs included
three medications never before identified in fish — diphenydramine (an
over-the-counter antihistamine also used as a sedative in
non-prescription sleep aids), diltiazem (a drug for high blood
pressure) and cabamazepine (an anticonvulsant).
Rapid, one-step, ultra-sensitive detection of
food poisoning bacteria and biothreats
A new mosquito-sized biosensor can detect amazingly
small amounts of disease-causing E. coli bacteria in food in a
single-step process that takes only minutes, compared to hours
required with conventional tests for that common food poisoning agent,
researchers in Philadelphia are reporting. The sensor also can quickly
detect proteins important in medical diagnostic testing and very low
levels of biothreats such as anthrax, according to the study,
published in the current (April 1) edition of ACS’ Analytical
Chemistry, a semi-monthly journal.
In the study, Raj Mutharasan and colleagues point
out that rapid measurements of very low concentrations of pathogens
and proteins could have wide application in medical diagnostic testing,
monitoring for biothreat agents, detecting contaminated food products
and other areas. Existing tests for low-level pathogens, however, take
time because they require a step to boost the concentration of
microbes in a sample. No direct test currently exists for low-levels
of proteins, the report adds.
The study describes use of the biosensor to detect
E. coli in ground beef and other materials at some of the
lowest concentrations ever reported. At the heart of the new biosensor
is a vibrating cantilever, with a tiny beam supported at one end and
coated with antibodies at its other, free-moving end. The antibodies
are specific to the material being detected, such as E. coli,
anthrax or proteins that are biomarkers for disease. When that antigen
is present in a sample flowing through the biosensor, it binds to the
cantilever and alters the frequency of vibration in a way that can be
detected electronically.
Bisphenol A (BPA), a weak synthetic estrogen used
in a variety of consumer products ranging from baby bottles to resins
that line food and beverage containers, has been linked in some
studies to adverse health effects in rodents, including obesity,
cancer and insulin resistance. There is growing concern that the
chemical may cause similar adverse effects in humans, particularly in
babies and young children. But there are vast discrepancies in the
findings of government-funded and industry experiments that have
explored the health effects of BPA, according to an opinion piece
article scheduled for the April 16 issue of Chemical & Engineering
News (C&EN), ACS’ weekly newsmagazine.
Among government-funded experiments on lab animals
and tissues, 153 found adverse effects and 14 did not, the magazine
reports. The majority of those that reported no harm were funded by
chemical corporations, the story notes. C&EN senior editor
Bette Hileman highlights a number of potential sources of bias behind
these inconsistent study outcomes, including the use of strains of
rats that are insensitive to estrogen and choosing batches of animal
feed that vary widely in their estrogenic activities.
Bias is even evident in the National Toxicology
Program’s assessment of BPA, the writer notes. A panel chosen to
review the data was selected with help from Sciences International, an
outside contractor with ties to two BPA manufacturers. The panel’s
review omitted critical studies and misclassified some of the studies,
according to the article. Only an unbiased panel with appropriate
expertise can resolve apparently conflicting results of these health
studies, Hileman says.
Cell phones qualify as hazardous waste, say
researchers
The cell telephones that consumers in the United
States discard by the millions each year classify as hazardous waste,
according to a study published in the current (April 1) issue of the
ACS’ Environmental Science & Technology, a semi-monthly journal.
Oladele A. Ogunseitan and colleagues at the
University of California at Irvine cite long-standing concerns about
the quantity of consumer electronics products that wind up in dumps
and landfills. They estimate that more than 700 million cell phones
already have been discarded or are stockpiled awaiting disposal, with
130 million cell phones trashed in 2005 alone.
In the new study, researchers used standard lab
procedures to analyze chemicals in simulated cell phone "leachate" —
the liquid that dribbles out into the soil from cell phones in dumps
and landfills. Lead in the leachate was high enough to make cell
phones classify as hazardous waste under Federal regulations, the
study found. Lead-free phones, however, still are classified as
hazardous waste under California regulations due to high levels of
copper, nickel, antimony and zinc in the leachate.
The findings have "profound implications" for the
ultimate disposal of cell phones, the researchers said. "These data
demonstrate that electronics manufacturers who seek to design products
exempt from current hazardous waste classifications will need to
address not just lead, as the current wave of responses to European
and Japanese regulations has shown, but also nickel, antimony and zinc,
and most importantly, copper content."
Toward a noninvasive diagnostic test for women
at high risk of preterm birth
With pre-term births a major international health
problem, scientists are reporting an advance toward developing a
much-needed, noninvasive test for predicting when pregnant women are
about to deliver early. Oregon Health Science University’s Srinivasa
R. Nagalla and colleagues there and at the University of Washington in
Seattle, report the discovery of protein biomarkers that could lead to
such a test. The work is reported in the April 9 issue of ACS’
Journal of Proteome Research, a monthly publication.
In the report, researchers explain that spontaneous
preterm births (before 37 weeks of pregnancy) have increased steadily
during the last 25 years and now account for 70 percent to 80 percent
of neonatal deaths. Development of a rapid diagnostic test for
pre-term labor thus would be a major advance, they added.
The researchers analyzed cervical-vaginal fluid
from 18 women, including six with spontaneous preterm birth, six with
preterm labor, and six controls. They identified proteins that were
present in women with preterm deliveries that could eventually serve
as biomarkers for the condition. While emphasizing that the finding
should be confirmed in a larger group of women, the study terms it an
important step toward identifying women at high risk for preterm birth.
Geochemists Take Calculi Off The
Heart
Researchers have found out where heart calculi come from. Generally,
geochemists’ task is to investigate how apatite sediments - main
source of phosphorus for mankind - are formed in nature.
Yale scientists discover footprints of shared
protons.
This week in Science, Yale researchers present "roadmaps"
showing that shared protons, a common loose link between two
biological molecules, simply vibrate between the molecules as a local
oscillator, rather than intimately entangling with the molecular
vibrations of the attached molecules.
Laser goes tubing for faster
body-fluid tests
Researchers announce in the current issue of Applied Optics a
technique that in 60 seconds or less measures multiple chemicals in
body fluids, using a laser, white light, and a reflective tube.
Polyphenols on a plate Like vitamins, the polyphenols found
in food are beneficial to health. A recent study showed that apples
and potatoes alone supply half the total polyphenols obtained from
fruit and vegetable consumption in France.
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