Using
catalysts to stamp nanopatterns without ink
Using enzymes from E. coli bacteria, Duke University chemists and
engineers have introduced a hundred-fold improvement in the precision
of features imprinted to create microdevices such as labs-on-a-chip.
Good news for lovers of fish and chips, Japanese
scientists have come up with the perfect recipe to make a crispy
batter which is also lower in fat, reports Joanna Harries in Chemistry
& Industry, the magazine of the SCI.
Dr Thanatuksorn and his team at Tokyo University of
Technology studied how the structure of the batter molecules changes
during the frying process. By altering the water content and frying
time they were able to suggest the perfect conditions to create batter
with the best lasting crispiness, as well as helping to reduce the fat
content.
During the deep-frying process a rigid
microstructure of pores is formed in the batter, and this
microstructure is responsible for the textural properties of the food,
as well as determining how much oil is absorbed during the frying. The
amount of water in the batter before and after frying is critical.
Water evaporates during cooking creating the pores responsible for
crispiness, but residual moisture remaining after causes the batter to
go soggy.
According to Thanatuksorn�s research, larger pores
trap less oil during cooking so will reduce the amount of fat in the
cooked food. By using a batter with a moisture content of 60% and
frying for 5 minutes a highly crisp lower-fat batter is formed. The
scientists say the residual moisture should be less than 5%.
Thanatuksorn says this method can be extended to
other food types, so next on the menu could be perfect chips.
CD-ROMs and DVDs and the hardware used to play
these popular audio and video compact discs (CDs) have �enormous�
potential as a new generation of portable, inexpensive instruments for
home health monitoring and laboratory-based testing, scientists in
Spain are reporting in the Oct. 15 issue of ACS� Analytical Chemistry,
a semi-monthly journal. CD technology could be adapted for tests
ranging from the measurement of environmental toxins to at-home
disease diagnosis, their report said.
In the study, Angel Maquieira and colleagues
demonstrated technology that uses ordinary CDs and CD players as
analytical tools with the potential for performing a range of key
laboratory tests. As proof of principle, they developed a CD with a
surface coating of so-called immunoassay materials and used it to
identify three pesticides - 2,4,5-TP, chlorpyriphos, and metolachlor �
placed on the disc. Upon spinning in a CD player with its standard
laser light, the compounds caused changes in light intensity. A
computer interpreted those changes and correctly named the compounds.
�The obtained results show the enormous prospective
of compact discs in combination with CD players for multiresidue and
drug discovery applications,� the article states. The researchers are
currently working on ways to increase the sensitivity and versatility
of the new technique.
Toward pure white light: Next-generation LEDs
show bright promise
Scientists in India are reporting an advance toward
discovering a Holy Grail of the illumination industry - a white LED, a
light-emitting diode that produces pure white light suitable for
interior lighting of homes, offices and other buildings. Their study
is in the Sept. 9 issue of ACS� The Journal of Physical Chemistry C, a
weekly publication.
In the report, D. D. Sarma and Angshuman Nag point
out that practical versions of these so-called white LEDs would be
brighter, longer-lasting and more energy efficient than conventional
light sources such as incandescent and fluorescent lamps and could
replace them in the future. However, scientists have faced several
difficulties in developing pure white LEDs with all the requirements
and desirable properties. Existing versions produce tinted, unstable
shades of white light that mar their performance.
The researchers report the first success in
developing a new LED based on a new phosphor from semiconductor
nanocrystals of cadmium sulfide mixed with manganese. It produces a
stable shade of white light that remains constant over time and
appears superior in overall performance in comparison to previous
generations of white LEDs. The scientists now are working to boost its
efficiency so that the white LED can be used in everyday applications.
Pomegranate juice: Tart, trendy, and targeted on
prostate cancer cells
Journal of Agricultural and Food Chemistry
Researchers in California are reporting new evidence explaining
pomegranate juice�s mysterious beneficial effects in fighting prostate
cancer. In a study scheduled for the Sept. 19 issue of ACS� Journal of
Agricultural and Food Chemistry, a bi-weekly publication, Navindra
Seeram and colleagues have found that the tart, trendy beverage also
uses a search-and-destroy strategy to target prostate cancer cells.
In previous research, Seeram�s group found that
pomegranate juice consumption had a beneficial effect for prostate
cancer patients with rising prostate-specific antigen (PSA) levels.
Such increases in PSA signal that the cancer is progressing, �doubling
time� a key indicator of prognosis. Men whose PSA levels double in a
short period are more likely to die from their cancer. Pomegranate
juice increased doubling times by almost fourfold.
In the new study, they researchers discovered
evidence in laboratory experiments that pomegranate works in a �seek
and destroy� fashion. On consumption, ellagitannins (ET), antioxidants
abundant in pomegranate juice, break down to metabolites known as
urolithins. The researchers showed that the urolithins concentrate at
high levels in prostate tissue after being given orally and by
injection to mice with prostate cancer. They also showed that
urolithins inhibited the growth of human prostate cancer cells in cell
culture.
�The chemopreventive potential of pomegranate
ellagitannins and localization of their bioactive metabolites in mouse
prostate tissue suggest that pomegranate may play a role in prostate
cancer treatment and chemoprevention,� the researchers state,
recommending further clinical studies with pomegranate and prostate
cancer patients.
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Printing with enzymes instead of ink
With all the advances in printing technology in
recent years, the latest may rise to the top of a list that would make
Gutenberg gasp. Scientists in North Carolina are reporting development
and testing of a method for printing finely-detailed microscopic
images with an enzyme, rather than ink.
In the study, Eric J. Toone and Robert L. Clark and
colleagues point out that so-called microcontact printing has found
wide application for rapidly transferring high-resolution images onto
large surfaces. But current nanoprinting technology relies on the
diffusion of ink, and cannot reproduce details smaller than one
hundred nanometers in diameter - about 400 times smaller than the
width of a human hair.
The new technology, termed biocatalytic
microcontact printing, involves coating a nano-�stamp� with an enzyme
- a protein that speeds up chemical reactions.
The enzyme then digests away a layer on the surface,
leaving behind an imprint almost like an old-fashioned rubber stamp.
Because no diffusion of ink is involved in the process, the resolution
of microcontact printed images is about one hundredfold greater than
possible with conventional technology. The technique may point the way
toward faster, less expensive methods of nanolithography, which could
be used to create complex structures for micromachines, biosensors,
and other nanoscale devices, the researchers suggest.
Drug-resistant tuberculosis rises, but new
treatments in the pipeline
An arsenal of promising new medications, vaccines,
and diagnostic tests are moving toward the global battlefield that
pits medicine against drug-resistant tuberculosis (TB), which is
claiming a terrible toll, particularly in HIV-infected individuals,
according to an article of Chemical & Engineering News, ACS� weekly
newsmagazine.
In the cover feature, C&EN senior correspondent Ann
Thayer and assistant editor Carmen Drahl describe far-ranging efforts
underway to develop new TB diagnostic tests and treatments. For years,
conventional treatments for TB had slowed the spread of the disease,
but the emergence of new drug-resistant strains has reduced the
effectiveness of those medications. Researchers are developing more
accurate diagnostic tests, new drugs to fight multidrug resistant
strains, and ones that are more compatible with individuals who are
undergoing treatment for HIV. Scientists are also developing more
effective vaccines, including those that might show promise for both
preventing and treating the disease, Thayer notes.
�In the past five years or so, the TB drug pipeline
has shifted from nearly empty to having about 30 compounds under
investigation; several are in early clinical testing,� Thayer writes.
Chemical & Engineering News: �Taking Down TB�.Taking
Down TB
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How much is a
kilogram?
A better definition for the kilogram? Scientists propose a precise
number of carbon atoms.
Argon conclusion
Researchers reassess theories on formation of Earth's atmosphere.
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CO2
emissions could violate EPA ocean-quality standards within decades
In a commentary of the Geophysical Research Letters a large team
of scientists state that human-induced carbon dioxide (CO2)
emissions will alter ocean chemistry to the point where it will
violate U.S. Environmental Protection Agency Quality Criteria [1976]
by mid-century if emissions are not dramatically curtailed now.
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Researchers
Genetically Engineer Microorganisms into Tiny Factories
Micro-organisms may soon be efficiently and inexpensively producing
novel pharmaceutical compounds, such as flavonoids, that fight aging,
cancer or obesity, as well as high-value chemicals, as the result of
research being conducted by University at Buffalo researchers.
Researchers at the Georgia Institute of Technology
have developed a miniature sensor that uses polymer membranes
deposited on a tiny silicon disk to measure pollutants present in
aqueous or gaseous environments. An array of these sensors with
different surface coatings could be used during field-testing to
rapidly detect many different chemicals.
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Sweet Smell of
The Good Earth
Brown Chemists Explain the Origin of Soil-Scented Geosmin:
Chemists have figured out precisely how the warm, slightly
metallic scent of freshly turned soil is made. In a open access
article of Nature Chemical Biology, the team describes how geosmin,
the organic compound responsible for the scent, is produced by an
unusual bifunctional enzyme.
Mechanism for
the in-vivo transport of siRNA
RNA interference, a natural mechanism that inhibits the gene
expression of individual genes in eukaryotic cells, is a major topic
in modern biology. However, their potential was usable to only a
limited extent in mammals because the mechanism for the uptake of
small RNAs was unknown up to now. ETH Zurich biologists have now
clarified this, which also opens the door for therapies based on this
mechanism.
This "briefcase" is actually an anti-terror device for
detecting homemade bombs.
Image: Courtesy of Joseph P.
Hutchinson, University of Tasmania, Australia
New technology for tracking down builders of
homemade bombs
Researchers in Australia are reporting development
of a portable device to help track down builders of improvised
explosive devices (IEDs) - those homemade fertilizer bombs that have
wreaked such havoc in terrorist attacks around the world. Their study
appeared in the Sept. 15 issue of ACS� Analytical Chemistry, a
semi-monthly journal.
Paul R. Haddad and colleagues point out that IEDs
have become a mainstay weapon for terrorists, resulting in an urgent
need for new technology to identify and eliminate the sources of the
explosives. However, quickly and reliably identifying the chemicals
used in these crude but deadly bombs remains a major challenge to
investigators. IEDs are often made with a diverse array of
conventional, easy-to-obtain materials that require slow and
painstaking analysis in the laboratory following an explosion.
The new technology streamlines that process,
quickly and accurately identifying the chemical composition of blast
residues from IEDs in the field. It consists of an instrument, about
the size of a briefcase, based on a modified form of capillary
electrophoresis, a mainstay technology for separating components in a
mixture. In the study, researchers used it to identify major
components of blast residues in less than 10 minutes.
New way to watch the lipid flip - flippases,
flopases, and scramblases
The �lipid flip� may sound like a rock and roll
dance craze from the 1960s. However, it actually is a key biochemical
process in which fatty materials termed lipids move into cells -
movements that are pointing toward improvements in gene therapy, new
medications for preventing the complications of Alzheimer�s disease,
and other health boons.
In an article in the Sept. 19 (2007) issue of ACS�
Bioconjugate Chemistry, a bi-monthly journal, Vladimir Sidorov and
colleagues report development of a new non-invasive method for
monitoring the activity of lipid-flipping enzymes. Colorfully named
flippases, flopases, and scramblases, these enzymes control the
process in which lipid molecules literally summersault from the outer
layer of a cell membrane to the inner layer where they can move into
the cell itself. The actions of those enzymes can influence blood
clotting, whether a cell lives or programs itself for death, and other
processes.
In their study, the researchers describe drawbacks
in existing methods for monitoring lipid. Their new laboratory method
overcomes those problems, and permits monitoring of the lipid flip in
actual cell membranes in real time, as the process unfolds.
Photo and illustration (inset) of carbon nanotube
circuits.
Image: Courtesy of Ze�ev Abrams and
Yael Hanein, Tel-Aviv University, Israel
Toward next-generation integrated circuits made
from carbon nanotubes
Scientists in Israel are reporting the first simple
and inexpensive method for building the large-scale networks of
single-walled carbon nanotubes (SWCNT) needed for using these
microscopic wisps in a future generation of faster, smaller, and more
powerful computers and portable electronic devices.
In a study in the Sept. 12 (2007) issue of ACS�
Nano Letters, a monthly journal, Yael Hanein and colleagues point out
that no assembly method has solved all of the key problems involved in
fabrication of large networks. Those problems range from aligning
SWCNTs in a preset pattern to integrating carbon nanotube circuits
into an integrated circuit environment similar to those at the heart
of conventional microprocessors.
The study describes a method to manufacture and
assemble large arrays of SWCNTs into an integrated circuit format. It
can be used on a variety of surfaces and produced on an industrial
scale. The process involves creating networks of nanotubes suspended
between silicon pillars, which are then transferred onto other
surfaces by direct stamping, the researchers say.
Fast, portable test promises to help detect
flammable liquids in arson
Researchers in Ohio are reporting development of an
inexpensive portable test for accurately identifying flammable liquids
used in arson - the leading cause of fires and the second leading
cause of fire deaths in the United States.
Identification of flammable liquids used in arson
usually requires time-consuming laboratory tests, Yao Lu and Peter
Harrington point out. The new test, called gas
chromatography-differential mobility spectrometry (GC-DMS), works fast
and is small enough for use in the field, they say.
In laboratory studies, the researchers added seven
different flammable liquids to carpet samples and then ignited the
samples to simulate an arson event. Analysis of the burned carpet with
GC-DMS identified the individual flammable liquids with an accuracy
rate of 99 percent. The results demonstrate that this novel test
�could be successfully used for forensic analysis of ignitable liquids
from fire debris,� the report states.
Preventing future bridge collapses: Protective
coatings may hold key
In the wake of the tragic bridge collapse in
Minnesota and last year�s shut down of an oil pipeline in Alaska due
to corrosion, researchers are facing increased pressure to develop
better protective coatings to help save aging infrastructures,
according to an of Chemical & Engineering News, ACS� weekly
newsmagazine.
Protective coatings and paints, such as epoxy
resins and polyurethanes, are designed primarily for warding off
corrosion in metal-based structures such as bridges, storage tanks and
buildings. Part of a fast-growing, multibillion dollar industry, these
chemicals have played an important but unsung role in protecting
structures for many years, writes C&EN Senior Editor Alexander H.
Tullo.
In the article, Tullo highlights efforts by coating
manufacturers to balance long-term coating protection with growing
customer demand for ease of use and lower prices and societal demands
for reducing volatile organic emissions from paints and other coatings.
He describes new multi-functional coatings that reduce the number of
protective coats applied while retaining maximum coating performance
and faster-acting curing agents that get paint jobs finished more
quickly.
But disasters aren�t the only thing fueling demand
for better coatings. A boom in construction work in emerging economies
in China, India, and Eastern Europe is also increasing demand, Tullo
notes.
Revealing
the workings of 'Mother Nature's blowtorch'
Using atom-level imaging techniques, researchers have revealed
important structural details of an enzyme system known as "Mother
Nature's blowtorch" for its role in helping the body efficiently break
down many drugs and toxins.
Probing a rare
material spin state at NIST
A team of researchers has found experimental evidence of a highly
sought-after type of arrangement of atomic magnetic moments, or spins,
in a series of materials.
Nuclear
physicists examine oxygen's limits
Physicists have made a unique measurement of an exotic oxygen nucleus, leading
scientists one step closer to deciphering the behavior of the element at
its limits of existence.
-
Using green
chemistry to deliver cutting-edge drugs
Green chemistry is being employed to develop revolutionary drug
delivery methods that are more effective and less toxic
- and could benefit millions of patients.
Dozens of cancer-clogging drug molecules loaded
onto tiny gold sphere.
Open access article: Gibson,
J. D.; Khanal, B. P.; Zubarev, E. R. - Paclitaxel-Functionalized Gold
Nanoparticles - publisahed in J. Am. Chem. Soc.; (Article); 2007;
129(37); 11653-11661; doi: 10.1021/ja075181k.
Scientists at
the Georgia Institute of Technology have developed a new technique for
nanolithography that is extremely fast and capable of being used in a
range of environments including air (outside a vacuum) and liquids.
Research Suggests Sulfur, Nitrogen Emissions Play a
Role in Changing Chemistry Near the Coast.
Open access articel "Impact of anthropogenic atmospheric nitrogen and sulfur deposition
on ocean acidification and the inorganic carbon system", published
in PNAS.
PCBs may threaten killer whale populations for
30-60 years
Orcas or killer whales may continue to suffer the
effects of contamination with polychlorinated biphenyls (PCBs) for the
next 30 - 60 years, despite 1970s-era regulations that have reduced
overall PCB concentrations in the environment, researchers in Canada
report. Their study, which calls for better standards to protect these
rare marine mammals, is scheduled for the Sept. 15 issue of ACS�
Environmental Science & Technology, a semi-monthly journal.
In the study, Brendan Hickie and Peter S. Ross and
colleagues point out that orcas face a daunting array of threats to
survival, including ship traffic, reduced abundance of prey and
environmental contamination. Orcas, which reach a length exceeding 25
feet and weights of 4-5 tons, already are the most PCB-contaminated
creatures on Earth. Scientists are trying to determine how current
declines in PCBs in the environment may affect orcas throughout an
exceptionally long life expectancy, which ranges up to 90 years for
females and 50 years for males.
The new study used mathematical models and
measurements of PCBs in salmon (orcas� favorite food) and ocean floor
cores to recreate a PCB exposure history to estimate PCB
concentrations in killer whales over time. It concluded that the
�threatened� northern population of 230 animals will likely face
health risks until at least 2030, while the endangered southern
population of 85 orcas may face such risks until at least 2063. PCBs
make whales more vulnerable to infectious disease, impair reproduction,
and impede normal growth and development, the researchers say.
�The findings provide conservationists, regulators,
and managers with benchmarks against which the effectiveness of
mitigative steps can be measured and tissue residue guidelines can be
evaluated,� the study reported. �The results of our study on PCBs may
paint an ominous picture for risks associated with emerging chemicals,
as the concentrations of structurally-related PBDEs are doubling every
4 years in marine mammals,� researchers added.
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With help from chemists,
cassava is being transformed into a healthier crop.
Discovery promises more nutritional cassava (yucca)
for developing world
An intensive international effort to improve the
nutritional value of cassava - a staple food for millions of poverty
stricken people in sub-Sahara Africa and other areas - has led to
development of a New form of cassava that may be easier to digest than
other varieties. A report on the advance is scheduled for the Sept. 5
issue of ACS' Journal of Agricultural and Food Chemistry, a bi-weekly
publication.
Also known as yucca or manioc, the roots of the
plant are similar to potatoes and are often eaten boiled or deep fried.
The roots are also used to make flour, tapioca, and a wide range of
other food products. While the roots are low in protein and vitamins,
they are an abundant source of starch. But the starch contains
relatively high levels of amylose, which can be difficult to digest.
In the new study, Hernan Ceballos and colleagues
identified a variety of cassava with less than 3 percent amylose,
compared to 18-24 percent of the hard-to-digest material in
traditional cassava. �This is the first report of a natural mutation
in cassava that drastically reduces amylose content in root starch,�
the study states. This mutation may also be better suited for the
production of bioethanol, it adds.
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�Lung on a chip� and other marvels from
microfluidic devices
Tiny new laboratory tools termed microfluidic
devices are helping biomedical researchers to better understand the
physiological and chemical processes underlying high blood pressure,
stroke, sickle cell disease and other disorders, according to an
article scheduled for the Sept.10 issue of Chemical & Engineering
News, ACS� weekly newsmagazine.
Among the exciting developments described in the
article is a �lung on a chip� device that will give researchers new
insights into fluid dynamics in the diseased lung - a key to new
treatments for pneumonia, cystic fibrosis and asthma.
In the C&EN cover story, senior editor Celia Henry
Arnaud describes how microfluidic devices, which include such features
as micrometer-scale channels and wells as part of sophisticated
�lab-on-a-chip� instruments, provide unprecedented biological realism
needed to shed light on today�s most challenging medical problems. The
devices enable scientists to study the kinds of fluid movements and
chemical interactions that occur in cells, tissues, and even organs in
ways that aren�t possible with test tubes and Petri dishes, Arnaud
notes.
Blocking formation of toxic plaques implicated
in type 2 diabetes
Amid growing evidence that the same abnormal
clumping of proteins in Alzheimer�s disease also contributes to type-2
diabetes, scientists in New York are reporting discovery of a potent
new compound that reduces formation of those so-called amyloid plaques.
Their study is scheduled for the Sept. 5 issue of the Journal of the
American Chemical Society, a weekly publication.
The report cites evidence correlating increases in
amyloid formation in the pancreas with increases in severity and rate
of progression of type-2 diabetes, which affects almost 20 million
Americans and is rapidly rising worldwide. Deposits of the abnormal
protein damage and destroy insulin-producing �islet� cells in the
pancreas. Researchers have been seeking potential new medicines that
block formation of an abnormal, misfolded protein called islet amyloid
polypeptide (IAPP), which may play a key role in the cell destruction.
In the new study, Daniel Raleigh, Andisheh Abedini
and Fangli Meng found that changing a single amino acid in human
IAPP�s structure transformed it from one of the most potent
amyloid-forming substances into a powerful inhibitor of amyloid
formation. In laboratory studies, they showed that the mutant IAPP
significantly reduced the amount of amyloid formed. In addition to
opening the door for better IAPP inhibitors in type-2 diabetes, the
findings provide potentially important insights into the formation and
treatment of amyloid plaques in Alzheimer�s disease, Parkinson�s
disease, and other conditions, the researchers say.
In a finding that could reduce the cost of ethanol
fuel, researchers in Brazil report success in using low frequency
magnetic waves to significantly boost the amount of ethanol produced
through the fermentation of sugar. Their study is scheduled for the
Oct. 5 issue of ACS� Biotechnology Progress, a bi-monthly journal.
While bioethanol (ethanol produced from corn and
other plants) is a promising alternative to fossil fuels, it currently
is expensive and inefficient to make. An intensive research effort now
is underway to improve production methods for this biofuel, which is
expected to be the cornerstone of the renewable fuel industry.
In a new study, Victor Perez and colleagues showed
that yeast-based fermentation of sugar cane - the main source of
bioethanol in Brazil - in the presence of extremely low frequency
magnetic waves boosted ethanol production by 17 percent. The
scientists also showed that ethanol production was faster, taking two
hours less than standard fermentation methods. �The results presented
in this report suggest that an extremely low frequency magnetic field
induces alterations in ethanol production by S. cervisiae [yeast] and
that the magnetic field treatment can be easily implemented at an
industrial scale,� the article states.
New method reveals substances on surfaces of any kind
ETH Zurich researchers have developed a new method that allows even
the surfaces of living organisms to be examined quickly and simply.
The method opens up interesting new possibilities not only in medicine
but also in foodstuffs monitoring.
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Skin oil
Ozone interactions worsen air quality in airplanes.
A
Nano-Microscope for Ultrafast Processes
International team of scientists proposes new ultramicroscope for
nanostructures, allowing for the direct and non-invasive measurement
of ultrafast processes on attosecond timescales with high spatial and
temporal resolution.
