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.
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.
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.
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.
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.
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