With prices of gourmet coffee approaching
sticker-shock levels, scientists in Illinois are reporting development
of a method to �fingerprint� coffee to detect when corn has been mixed
in to short-change customers. Their study is in the Aug. 8 issue of
ACS�s Journal of Agricultural and Food Chemistry, a bi-weekly journal.
Gulab Jham and colleagues point out that such
adulteration of Brazilian coffee is among the most serious problems
affecting coffee quality - with cereal grains, coffee twigs, and brown
sugar sometimes mixed into the genuine article. Their research focuses
on detecting corn, probably the most widely used adulterant.
The study describes development and use on six
popular coffee brands of a method for analyzing one form of vitamin E
in Brazilian coffee. Because roasted corn samples have high
concentrations of vitamin E, it serves as a fingerprint for
adulteration with corn. In laboratory tests they found that one brand
of Brazilian coffee contained almost 9 percent corn. Although noting
that their results are preliminary, the scientists say their new
method appears to be �a significant improvement� over existing tests
to detect corn adulteration.
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Tiny carbon nanotubes show big germ-fighting
potential
In nanoscience�s version of a David-and-Goliath
story, scientists in Connecticut are reporting the first direct
evidence that carbon nanotubes have powerful antimicrobial activity, a
discovery that could help fight the growing problem of antibiotic
resistant infections. Their research on so-called single-walled carbon
nanotubes (SWNTs) is scheduled for publication in the current (Aug.
28) issue of ACS� Langmuir, a bi-weekly journal.
Menachem Elimelech and colleagues point out that
past research on the toxicity of SWNTs has focused on their adverse
human and environmental effects. These microscopic cylinders of carbon
- thousands of times smaller than a human hair - are one of the most
promising raw materials for commercial and industrial applications of
nanotechnology in the 21st century. Their potential uses range from
biosensors to new drug delivery systems.
�Surprisingly, however, no published studies exist
on the direct interaction of SWNTs with microbes,� their report states.
�Our experiments provide the first direct evidence that highly
purified SWNTs exhibit strong antimicrobial activity and indicate that
severe cell membrane damage by direct contact with SWNTs is the likely
mechanism responsible for the toxicity to model bacteria. These
observations point to the potential use of SWNTs as building blocks
for antimicrobial materials.�
Nanomagnetic sponges to clean precious works of
art
Chemists in Italy are reporting �a real
breakthrough� in technology for cleaning and conserving priceless oil
paintings, marble sculptures and other works of art in an article in
the Aug. 14 issue of ACS� Langmuir, a bi-weekly journal. In the report,
Piero Baglioni and colleagues describe development and successful
testing on artworks of �nanomagnetic sponges� that could have a range
of other applications in cosmetics, detergents, and biotechnology.
Highlighting potential uses in art conservation,
the report explains that conservators often use solvents and other
cleaning agents in a gel formulation, somewhat similar in consistency
to gelatin desert. Compared to liquids, gels have less of a tendency
to soak deep into the surface of artwork and cause damage. Gels,
however, are difficult to remove from painted surfaces and may leave
behind undesirable residues.
The new nanomagnetic sponges - made from
nanoparticles so small that about 10,000 would fit across the diameter
of a human hair - overcome that problem, the report states. The
sponges can be loaded with solvents and other cleaning agents, and cut
with a knife or scissors into desired shapes for application to
specific, soiled areas of a painting. When the cleaning is done,
conservators can remove the gel with a magnet. �The nanomagnetic gel
represents the most advanced and versatile system for cleaning and
will have a dramatic impact on the conventional methods used in the
conservation field and in several other fields where fine tuning of
the release or uptake of confined material is required,� the report
states.
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Toward improved drug-delivery: Coating gives
nanowires easy access to cells
Scientists in Idaho and Korea are reporting
development of a protein coating that may turn nanowires into a new
drug delivery system that could allow use of lower doses of medicine
that are less harmful to normal cells. In a report scheduled for the
Sept. 12 issue of ACS� Nano Letters, a monthly journal, they describe
use of the coating to enable silica nanowires to enter cultured human
cells and deliver a lethal dose of toxin.
Gregory Bohach, David McIlroy, Carolyn Hovde, and
their colleagues point that nanowires and other nanomaterials (NMs),
which are 50,000 times smaller in diameter than a human hair, have
great potential as new drug delivery systems. NMs may penetrate tumors
more easily, for instance, and could be coated with antibodies or
other materials that home in on target cells while sparing normal
cells.
One roadblock, however, involves finding ways to
enable NMs to easily penetrate cells. The researchers report nanowires
coated with the protein fibronectin penetrate cells more easily than
uncoated nanowires. In experiments with human and animal cells, they
showed that coated nanowires can enter and deliver a toxic agent
called StxA1 that killed the cells. �This indicates that nanowires can
carry StxA1 and potentially other toxic or therapeutic agents into
cells,� the researchers said.
Memory enhancement drugs show promise but face
growing scrutiny
In our aging society, with an increased urgency to
develop new compounds that target serious illnesses like Alzheimer�s
and Parkinson�s disease, memory enhancement drugs are becoming a big
business. But these same drugs are also creating a growing ethical
controversy over their potential off-label uses, such as taking these
drugs as �performance enhancers� to gain a competitive advantage in
the workplace. These issues, along with the biochemistry of memory,
are explored in an article of Chemical & Engineering News (C&EN), ACS�
weekly newsmagazine.
Right now, there are only a handful of
memory-enhancing drugs on the market. In the C&EN cover story, senior
editor Sophie L. Rovner describes work at several companies, from
small start-ups to pharmaceutical giants, that are developing and
testing a variety of memory enhancing products that show promise for
the treatment of Alzheimer�s, Parkinson�s, stroke and schizophrenia.
In the continuing search for better drugs, even familiar compounds
such as nicotine and coffee are being explored for their potential
memory-enhancing effects, Rovner notes.
Despite their promise, there�s growing regulatory
and ethical concern about the use of such drugs for non-medical
purposes. This includes using memory-enhancing compounds as stimulants
to gain a competitive edge in the workplace or even on exams, which
could result in unfair advantages over people who do not use the drugs.
The possibility of off-label or recreational uses of these drugs could
ultimately limit their wider acceptance, the article suggests. For
better or for worse, memory-enhancing drugs are poised to play a
bigger role in the future.
Brake linings and
tires source of major toxic emissions
Particles from the wear of brake linings and tires are still a major
source of emissions of toxic metals. Researchers at the University of
Kalmar in Sweden have studied city traffic in Stockholm and found that
the emission of toxic metals has not decreased appreciably despite
major environmental efforts by automakers.
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Nanowire coating for bone implants, stents
Researchers have found a simple, inexpensive way to create a nanowire
coating on the surface of biocompatible titanium that can be used to
create more effective surfaces for hip replacement, dental
reconstruction and vascular stenting.
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Nanotube formation: researchers learn to control the
dimensions of metal oxide nanotubes
Toward a new generation of low-cost,
high-efficiency solar cells
Solar energy, once regarded as costly and
impractical, is now poised to play a bigger, brighter role in meeting
future energy needs due to new materials and processes that offer
lower costs and improved efficiencies, according to an article [insert
link] scheduled for the Aug. 27 issue of Chemical & Engineering News,
ACS� weekly newsmagazine. With potential applications ranging from
homes to offices to portable electronics, solar energy could soon
become a common part of your daily lives.
The magazine�s cover story, by C&EN senior editor
Mitch Jacoby, includes interviews with of the world�s leading solar
energy experts. They describe the challenges of tapping into this rich
energy source and the new materials and strategies that are emerging
from their research.
The materials include semiconductor nanocrystals
that can be formed into flexible sheets and networks of nanowires for
improved electrical transport. Jacoby also describes new generations
of promising yet inexpensive solar cells, including low-cost �plastic�
solar cells based on semiconducting polymers.
�It�s tough to predict which class of materials and
solar cell design will be the winning combination that generates a
supply of clean, renewable, and affordable energy plentiful enough to
make a significant contribution to the world�s future energy needs,�
Jacoby writes. �The solution may come from new types of devices and
novel materials yet to be discovered or from creative ways of using
substances already in hand.�
Explosive crystal
300 years after its discovery, the crystal structure and molecular
structure of mercury fulminate are determined.
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New finding bubbles
to surface, challenging old view
Chemical engineers have discovered a fundamental flaw in the
conventional view of how liquids form bubbles that grow and turn into
vapors, which takes place in everything from industrial processes to
fizzing champagne.
Clemson scientists
shed light on molecules in living cells
Clemson University chemists have developed a method to dramatically
improve the longevity of fluorescent nanoparticles that may someday
help researchers track the motion of a single molecule as it travels
through a living cell.
Compound in
broccoli could boost immune system
A compound found in broccoli and related vegetables may have more
health-boosting tricks up its sleeves, according to a new study led by
researchers at the University of California, Berkeley.
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Follow your
nose: Houston air quality study finds a few surprises:
As a frequent addition to the list of America's most polluted cities,
Houston is no stranger to having more than just oxygen and carbon
dioxide in the air. But a University of Houston study found a few
surprising results in the air Houstonians breathe day in, day out:
mercury and formaldehyde. This is the first time mercury has been
measured in Houston's air, and scientists are still trying to figure
out what it's coming from.
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Revealing
estrogen's secret role in obesity
New research on the effects of the female sex hormone estrogen in the
brain lend credence to what many women have suspected about the
hormonal changes that accompany aging: Menopause can make you fat.
New capabilities increasing knowledge of heavy element
fate and transport.
Researchers at Pacific Northwest
National Laboratory are uniting theory, computation and experiment to
discover exactly how heavy elements, such as uranium and technetium,
interact in their environment.
