DNA repair mechanisms relocate in response to stress
Like doctors making house calls, some DNA repair enzymes can relocate to the part of the cell that needs their help, a collaborative team of scientists at Emory University School of Medicine has found.
New research finding could lead to more durable aircraft, automotive components.
Nanoscale pillar-like fibers that bridge together both sides of a crack and slow its growth, could lead to tougher, more durable components for aircraft and automobiles.
It's raining pentagons
Scientists have discovered a novel one dimensional ice chain structure built from pentagons that may prove to be a step toward the development of new materials which can be used to seed clouds and cause rain.
Bristly Spheres as Capsules Inorganic nanoparticles with a layer of hydrophilic polymer chains aggregate into complex nanostructures
[Image credit: Wiley-VCH].
Researchers discover a potential on-off switch for nanoelectronics
Elecrical resistance through a molecular junction can be turned ?on and off?? simply by pushing and pulling the junction. This feature could be used as a switch in future nanoscale electronic devices.
Predicting the ocean's role for global climate requires a profound understanding of the cycling of matter in the sea. Regarding nitrogen losses, scientists were apparently off the mark. A novel study reveals the complex interactions in the nitrogen cycle of the Eastern Tropical South Pacific oxgen minimum zone.
[Image source: Phyllis Lam, MPI; published in PNAS]
Johns Hopkins engineers have invented a method that could be used to help figure out how cancer cells break free from neighboring tissue, an "escape" that can spread the disease to other parts of the body ... [Diagram by Peter Searson]
Scientists are reporting
differences in the brains of nurse bees and forager bees.
Image by The American Chemical
Society
Adults facing unexpected career changes, take note.
Scientists from Brazil and Cuba are reporting that honey bees - a
mainstay for behavioral research that cannot be done in other animals
- change their brains before transitioning to that new job. Appears in
the current edition of ACS' monthly Journal of Proteome Research, the
research provides valuable insight into the biochemistry behind the
behavior, feats of navigation, and social organization in these
animals.
In the study, Marcelo Valle de Sousa and colleagues
point out that worker bees begin adult life by performing tasks in the
nest such as brood nursing. By 2-3 weeks of age, however, these
females - equivalent to middle age in human years - switch to foraging
for nectar and pollen. Foraging requires a new skill set that includes
uncanny ability to navigate to and from feeding sites, communicating
the location of food to other bees, and flights of hundreds of miles
in a lifetime.
The researchers collected and analyzed hundreds of
bee brains, comparing the proteins scripted by the genes in nurses and
foragers in order to find proteins related to the genetic and
behavioral shifts during these career transitions. The brains of nurse
bees have higher levels of certain "royal jelly" proteins involved in
caste determination. Experienced foragers, in contrast, over expressed
proteins linked to energy production and other activities.
"Our study demonstrated clear brain proteome
differences between honey bee nurse and forager subcastes with
distinct social roles," the study says. - AD
"Magic potion" in fly spit may shoo away
blinding eye disease
Scientists have found proteins in
the black fly?s saliva that help spread parasites that cause a
devastating eye disease.
Image by the US Department of
Agriculture, The Diptera Site
Researchers are reporting the first identification
of a "magic potion" of proteins in the saliva of the black fly that
help this blood-sucking pest spread parasites that cause "river
blindness," a devastating eye-disease. A better understanding of these
proteins may lead to better drugs and a vaccine for river blindness
and other diseases spread by biting insects. Also known as
onchocerciasis, river blindness affects more than 17 million people
worldwide, particularly in rural Africa. The report appears in the
current edition of ACS' Journal of Proteome Research, a monthly
publication.
In the new study, Jos?M.C. Ribeiro and colleagues
explain that the saliva of adult female black flies contains
substances that mute the human body's natural defenses. This chemical
cocktail makes the body more vulnerable to disease when infected flies
bite into the skin. Until now, however, nobody had identified the
specific chemicals involved in this devious action.
The scientists collected salivary glands from
hundreds of adult female black flies and isolated the proteins using
high-tech analytical gear. They identified 72 different proteins,
including several new to science. These proteins could serve as the
basis for developing drugs or vaccines against diseases transmitted by
the black fly and other blood-sucking insects, including mosquitoes,
midges, and sand flies, the researchers say. - MTS
New gas storage material: One ounce has surface
area of 30 football fields
A new nanomaterial could help
usher in hydrogen fuel cell vehicles.
Image by The American Chemical
Society
In a finding that may help speed the production of
ultra-clean fuel cell vehicles powered by hydrogen, scientists in
Michigan are reporting development of a sponge-like nanomaterial with
a record-high surface area for holding gases. Just 1/30th of an ounce
of the material has the approximate surface area of a football field.
Their study is scheduled for the April 1 issue of the Journal of the
American Chemical Society, a weekly publication.
Adam Matzger and colleagues note in the new study
that scientists have tried for years to find a material to optimize
hydrogen storage in futuristic fuel cell vehicles. Despite identifying
several promising materials, researchers have been unable to meet the
hydrogen storage goals proposed by the U.S. Department of Energy (DOE)
for hydrogen fuel cell vehicles, they state.
They describe development of a highly-porous
nanomaterial with an unprecedented ability to absorb gases that may
help meet DOE's target. Called University of Michigan Crystalline
Material-2 (UMCM-2), it consists of zinc oxide nanoclusters - each
about 1/50,000 the width of a human hair - linked together by organic
materials to generate a robust porous framework. The scientists showed
that UMCM-2 has a surface area exceeding 5,000 square meters per gram
which is, they say, the highest value ever achieved. - MTS
In a step toward using gas hydrates as a future
energy source, researchers in New York are reporting the first
identification of an optimal temperature and pressure range for
maximizing production of natural gas from the icy hydrate material.
Their study appears in the March 18 issue of ACS' Industrial &
Engineering Chemistry Research, a bi-weekly journal.
Marco Castaldi, Yue Zhou, and Tuncel Yegualp note
that gas hydrates, also known as "ice that burns," are a frozen form
of natural gas (methane). This material exists in vast deposits
beneath the ocean floor and Arctic permafrost in the United States and
other areas. Scientists believe that fuel from these frozen chunks,
formed at cold temperatures and high pressures, may help fuel cars,
heat homes, and power factories in the future. Although scientists
have identified several different methods for extracting the fuel,
including depressurization, researchers have not found an practical
approach for producing the gas on an industrial scale.
To reach this goal, the researchers built what they
believe to be the world's largest experimental reactor, filled with
sand, water, and methane, to simulate the formation gas hydrates (at
low temperatures and high pressure) and production of the gas. While
depressurizing the hydrates to free the methane, they observed an
optimal boost in gas production between a narrow range of temperatures
and pressures. Maintaining gas production at these settings could be a
key step in boosting production of methane at an industrial scale, the
researchers suggest. - MTS
Bonanza of new oral drugs offers hope for MS
patients
Years of scientific research on multiple sclerosis
(MS) are showing signs of paying off, with almost a dozen potential
new drugs in the final stages of clinical trials and moving toward
pharmacy shelves, according to an article scheduled for the April 6
issue of Chemical & Engineering News, ACS' weekly newsmagazine. Those
drugs could double the number of medications available to treat MS -
which affects about 400,000 people in the United States - over the
next several years.
In the article, C&EN senior editor Lisa Jarvis
explains that MS is a disease in which the immune system attacks
myelin, a protective coating on many nerve fibers. This attack
triggers a slowly worsening host of symptoms. Twenty years ago, few
effective medicines were available for these patients.
Many of the new drugs are pills rather than
injectable medicines, making it easier for patients to take the
medication over long periods of time. Most of the drugs ease the
immune system damage to myelin or offer protection to already-damaged
nerves.
New super-bouyant material: Life preserver might
float a horse
Scientists have developed miniature
super-bouyant boats that could lead to aquatic robots and other
futuristic devices.
Image by The American Chemical Society
Here's a story that might float your boat:
Researchers in China are reporting the development of miniature
super-bouyant boats that float so well that an ordinary life preserver
made from the same material might support a horse without sinking. The
advance, they say, might be difficult to apply to full-size craft.
However, it could lead to a new generation of aquatic robots for spy
missions and other futuristic devices, the scientists add. Their study
is reported in ACS Applied Materials & Interfaces, a monthly journal.
In the new study, Qinmin Pan and Min Wang note that
researchers have studied the chemistry of surfaces for years in an
effort to design novel drag-reducing and fast-moving aquatic and air
devices, such as boats and planes. Scientists have often turned to
nature for inspiration. One source: The water strider, whose highly
water-repellant (superhydrophobic) legs allow this insect to literally
scoot across water surfaces at high speeds. But researchers still have
not found a practical way to apply this phenomenon to technology.
Pan and Wang made several miniature boats about the
size of a postage stamp. They used copper mesh treated with silver
nitrate and other substances to make the boats' surfaces
superhydrophobic. When compared to similar copper boats made without
the novel surfaces, the water repellant boats floated more smoothly
and also showed a surprisingly large loading capacity. The best
performing mini-boat floated with up to two times its maximum
projected loading-capacity, the scientists say. "Interestingly, the
boat is able to keep floating even if its upper edges are below the
water surface," the scientists note. - MTS
First discovery of "animals-only" pigment
bilirubin in plants
Scientists are reporting discovery of bilirubin
in the white bird of paradise tree, the first example of this
pigment in plants. Shown is the plant's furry seed which contains
bilirubin.
Image by The American Chemical Society
In a first-of-its-kind discovery that overturns
conventional wisdom, scientists in Florida are reporting that certain
plants - including the exotic "White Bird of Paradise Tree" - make
bilirubin. Until now, scientists thought that pigment existed only in
animals. The finding may change scientific understanding of how the
ability to make bilirubin evolved, they say in a report in the Journal
of the American Chemical Society, a weekly publication.
In the new study, Cary Pirone and colleagues note
that bilirubin is a brownish yellow substance resulting from the
liver's breakdown of hemoglobin, the red pigment that carries oxygen
in the blood. Parents know bilirubin as the stuff that discolors the
skin of newborns with neonatal jaundice, sometimes requiring
phototherapy, treatment with light. Bilirubin also gives a yellowish
tinge to the skin of patients with jaundice resulting from liver
disease. Until now, scientists never dreamed that plants, as well as
animals, produce bilirubin.
The researchers used two powerful laboratory
techniques, liquid chromatography and nuclear magnetic resonance, to
detect bilirubin in fruit of the white bird of paradise tree. The
fruits contain unusual, orange-colored, furry seeds, and bilirubin
turns out to be the coloring agent. They also found the pigment in two
closely related plant species. The discovery may stir evolutionary
research to understand why and how plants make what everyone regarded
as an animals-only pigment, they suggest. - MTS
A new dating method finally is allowing
archaeologists to incorporate rock paintings - some of the most
mysterious and personalized remnants of ancient cultures - into the
tapestry of evidence used to study life in prehistoric times. That's
the conclusion of a new report in ACS' Analytical Chemistry, a
semi-monthly journal.
In the study, Marvin W. Rowe points out that rock
paintings, or pictographs, are among the most difficult archaeological
artifacts to date. They lack the high levels of organic material
needed to assess a pictograph's age using radiocarbon dating, the
standard archaeological technique for more than a half-century. Rowe
describes a new, highly sensitive dating method, called accelerator
mass spectrometry, that requires only 0.05 milligrams of carbon (the
weight of 50 specks of dust). That's much less than the several grams
of carbon needed with radiocarbon dating.
The research included analyzing pictographs from
numerous countries over a span of 15 years. It validates the method
and allows rock painting to join bones, pottery and other artifacts
that tell secrets of ancient societies, Rowe said. "Because of the
prior lack of methods for dating rock art, archaeologists had almost
completely ignored it before the 1990s," he explained. "But with the
ability to obtain reliable radiocarbon dates on pictographs,
archaeologists have now begun to incorporate rock art into a broader
study that includes other cultural remains." - JS
Record long platinum nanowires: An advance
toward better fuel cells
In an advance that could aid development of fuel
cells, researchers are reporting the longest platinum nanowires
ever made.
Image by The American Chemical Society
Researchers from New York are reporting production
of the longest platinum nanowires ever made - an advance that they say
could speed development of fuel cells for cars, trucks, and other
everyday uses. The wires, 1/50,000 the width of a human hair, are
thousands of times longer than any previously made, according to a
report scheduled for the March 11 issue of ACS' monthly journal, Nano
Letters.
In the article, James C. M. Li and colleagues point
out that short platinum nanowires already have been used in
sub-microscopic sensors and other applications. With platinum the
primary material used in fuel cells (which generate electricity
cleanly from hydrogen and oxygen), scientists have sought to produce
long wires from this precious metal. Those wires could be woven into
the first self-supporting webs of pure platinum for fuel cell
electrodes.
By a process known as electrospinning, the team
made platinum nanowires long enough to construct that web. "Our
ultimate purpose is to make free-standing fuel cell catalysts from
these nanowires. This technology is a key step toward better solutions,"
says Li. - AD
A new generation of simple, affordable medical
diagnostic tests is heading toward the developing world where they may
protect impoverished people from AIDS, tuberculosis, malaria and other
infectious diseases. That's the message from an article on these
simple medical diagnostics scheduled for the March 16 issue of
Chemical & Engineering News, ACS' weekly newsmagazine.
C&EN senior editor Celia Henry Arnaud explains that
scientists have designed the tests for the harsh realities that exist
in much of the developing world. Those include lack of modern
laboratory equipment, lack of refrigeration and unreliable sources of
pure water. Many of the new tests require no instruments and can be
read and interpreted by workers with minimal training. Some are
multi-purpose, capable of diagnosing several infections simultaneously
from a few drops of blood or urine, the article notes.
One new test, for example, can monitor levels of
key immune system cells in patients infected with HIV, the cause of
AIDS, and help determine when costly anti-viral therapy is needed. The
tests may also be a boon for the developed world, making health care
more affordable, the article suggests.
Improving rural sanitation by 65 percent could save
as many as 1.2 million lives a year worldwide, scientists in
Pennsylvania conclude in a new study on diarrheal disease. Their
report, in the current edition of ACS' semi-monthly journal
Environmental Science & Technology, found that developing countries in
Africa and Asia would experience the greatest savings in life.
In the study, Sean T. Green and colleagues note
that diarrhea causes 2.2 million deaths a year worldwide. It is the
third leading cause of childhood mortality after neonatal disorders
and respiratory infections. Many previous studies have tried to
identify the factors that contribute to child mortality. Only a few,
however, have evaluated the factors contributing to diarrheal disease
at a national level, leaving a major information gap on the topic.
The researchers developed a new computer model for
that purpose using an artificial intelligence technique called
Classification and Regression Trees. They used it to predict diarrheal
illness nationally, based on data from 192 countries. Using the model,
the scientists identified improvements in rural sanitation - such as
providing safe disposal of feces - as the measure in their study with
the single greatest impact in reducing deaths from diarrheal disease.
"The most important variable for reducing diarrheal illness in the
worst afflicted countries is rural sanitation, a message that can be
obscured with a 'one size fits all' linear regression model" like
those used in the past. - MB
Gooda, Gouda! Solving the 800-year-old secret of
a big cheese
Scientists have identified key substances that
give Gouda its complex taste.
Image by public-domain-photos.com
Almost 800 years after farmers in the village of
Gouda in Holland first brought a creamy new cheese to market,
scientists in Germany say they have cracked the secret of Gouda's good
taste. They have identified the key protein subunits, or peptides,
responsible for the complex, long-lasting flavor of the popular cheese.
That discovery could lead to development of more flavorful cheeses and
other dairy products. Their study is in the current issue of ACS'
Journal of Agricultural and Food Chemistry, a bi-weekly publication.
Thomas Hofmann, Simone Toelstede and Andreas Dunkel
note that the scientists have tried for years to pinpoint the natural
molecules responsible for the long-lasting taste and wonderful texture
of Gouda cheese. It develops during the aging or ripening stage, with
aged Gouda more full and complex, with longer-lasting flavor, than the
younger version. Cheese lovers prize this characteristic taste, known
as the "kokumi sensation."
The scientists solved the age-old mystery by
applying a molecular sensory science approach. It combined mass
spectroscopy and other high-tech analytical instruments and
sophisticated sensory tools to identify six gamma-glutamyl peptides
that appear to be mainly responsible for the kokumi sensation in Gouda.
This knowledge could be used to enhance the flavor of dairy products
by technological means, the researchers say. - MTS
New genre of sugar-coated "quantum dots" for
drug delivery
Quantum dots (QDs) capped with D-mannose,
D-galactose, and D-galactosamine have been synthesized. The stable,
high quantum yield fluorescence of QDs was exploited to study
specific carbohydrate-protein interactions in vitro and in vivo.
Image credit: American Chemical Society
Scientists in Switzerland are reporting an advance
that could help tap the much-heralded potential of "quantum dots"-
nanocrystals that glow when exposed to ultraviolet light - in the
treatment of cancer and other diseases. They are publishing the first
study showing that giving quantum dots an icing-like cap of certain
sugars makes these nanoparticles accumulate in the liver but not other
parts of the body. That selective targeting could be used to deliver
anti-cancer drugs to one organ, without causing the body-wide
side-effects that occur with existing cancer drugs, they suggest.
Their study is in the Feb. 18 issue of the Journal of the American
Chemical Society, a weekly publication.
In the new report, Peter H. Seeberger and
colleagues note that quantum dots, about 1/5,000th the width of a
human hair, are used in solar cells, medical diagnostic imaging, and
electronics. Scientists believe these particles also show promise for
drug delivery for treating cancer and other diseases. However,
researchers still have not found an ideal way to target these dots to
specific tissues or organs in order to maximize their effectiveness
and limit toxicity.
They describe development of a new type of quantum
dot coated with certain sugar molecules that are attracted to
receptors in specific tissues and organs. In a study with laboratory
mice, the scientists coated quantum dots with either mannose or
galactosamine, two sugars that accumulate selectively in the liver.
The sugar-coated dots became three times more concentrated in the mice
livers than the regular dots, demonstrating their higher specificity,
the researchers say. - MTS.
Old soles: 800-year-old shoe soles yield clues
about preservation of leather
A leather sole recovered from an archaeological
trash dump in Lyon, France.
Image by Pierre Alain Bayle
Ancient garbage can be like gold to archaeologists.
During excavation of an 800-year-old trash dump in Lyon, France,
scientists discovered the archaeological equivalent of golden shoe
soles: A trove of leather soles of shoes, which is helping scientists
understand how leather stays preserved in wet, oxygen-free
environments. That knowledge could aid restoration of other leather
artifacts, according to a report on analysis of the old soles
scheduled for the current issue of ACS' semi-monthly journal
Analytical Chemistry.
In the article, Michel Bardet and colleagues point
out that leather consists of collagen, a tough protein that can remain
intact hundreds of thousands of years under ideal conditions. The
French soles were buried in mud in the absence of oxygen - good
conditions for preservation.
They used laboratory technology called nuclear
magnetic resonance to compare composition of the ancient leather to
modern leather. It turned out that tannin, which helps to preserve
leather, had been washed out of the old soles and replaced by iron
oxides. The iron oxides, which leached into the leather from
surrounding soil, helped preserve the soles in the absence of tannins.
- AD
A new, more economical technology for decoding
genes is shuttling the long-awaited era of personalized medicine -
with doctors customizing prevention and treatment for each
individual's genetic endowment - closer to reality, according to an
article scheduled for the March 9 issue of Chemical & Engineering
News, ACS' weekly newsmagazine.
In the article, C&EN deputy assistant managing
editor Stu Borman describes a key advance toward a bargain-basement
DNA sequencer, a device to determine the chemical instructions in the
famed double helix molecule. Called a "nanopore sequencer," it could
replace higher-priced sequencing techniques currently in use. The
nanopore can identify all four DNA building blocks(adenine, thymine,
guanine, and cytosine) based on the amount of electric current these
so-called nucleotides block as they squeeze through the pore.
Nanopores could reduce the cost of gene sequencing to $1,000 for an
individual's genome, or complete genetic endowment. That compares with
the $100,000 to $1 million for sequencing an entire genome using
conventional techniques.
Although the nanopore sequencer still needs
tweaking, scientists are optimistic about its future potential. "This
is the first time a clear, feasible pathway to nanopore sequencing has
been shown," says one authority in the C&EN article.
Two food additives with previously unrecognized
estrogen-like effects in two food additives
Scientists have identified two
food additives with previously unrecognized estrogen-like effects.
One of the additives, 4-hexylresorcinol, is used to prevent
discoloration in shrimp and other shellfish.
Image credit: National Cancer
Institute, Renee Comet
Scientists in Italy are reporting development and
successful use of a fast new method to identify food additives that
act as so-called "xenoestrogens" - substances with estrogen-like
effects that are stirring international health concerns. They used the
method in a large-scale screening of additives that discovered two
additives with previously unrecognized xenoestrogen effects. Their
report appears in the current edition of ACS' Chemical Research in
Toxicology, a monthly journal.
In the study, Pietro Cozzini and colleagues cite
increasing concern about identifying these substances and about the
possible health effects. Synthetic chemicals that mimic natural
estrogens (called "xenoestrogens," literally, "foreign estrogens")
have been linked to a range of human health effects. They range from
reduced sperm counts in men to an increased risk of breast cancer in
women.
The scientists used the new method to search a food
additive database of 1,500 substances, and verified that the method
could identify xenoestrogens. In the course of that work, they
identified two previous unrecognized xenoestrogens. One was propyl
gallate, a preservative used to prevent fats and oils from spoiling.
The other was 4-hexylresorcinol, used to prevent discoloration in
shrimp and other shellfish. "Some caution should be issued for the use
of propyl gallate and 4-hexylresocrinol as food additives," they
recommend in the study. - MB
German scientists have developed
a test to differentiate real organic milk from fake.
Image by Max Rubner Institute,
Germany
Scientists in Germany are reporting development of
a new, more effective method to determine whether milk marketed as "organic"
is genuine or just ordinary milk mislabeled to hoodwink consumers.
Their report appears in the current edition of ACS' Journal of
Agricultural and Food Chemistry, a bi-weekly publication.
In the study, Joachim Molkentin and colleagues
point out that organic milk has soared in popularity in many countries.
Sales in Germany, for instance, rose by almost one-third between 2006
and 2007. Consequently, crooks may take advantage of the situation by
marketing increasing quantities of fake organic milk. That situation
created a need for better tests to detect the fraud.
To address the issue, the scientists developed a
test based on an analysis of milk fat for the ratio of stable isotopes
of carbon. They used it to identify milk samples from cows raised on
feed containing a higher ration of maize. Such a feeding regimen is
typical of conventional milk production. Organically raised cows are
fed less maize but more pasture feed. In addition, the team identified
a significant difference in the alpha-linolenic acid content of milk
fat between organic and conventional milk samples. Organic milk
typically has a higher alpha-linolenic acid content than conventional
milk. - MB
Scientists discover historic sample of
bomb-grade plutonium
This is a recovered glass bottle containing
several hundred milligrams of plutonium.
Image by The American Chemical Society
Scientists in Washington state are reporting the
surprise discovery of the oldest known sample of reactor-produced
bomb-grade plutonium, a historic relic from the infancy of America's
nuclear weapons program. Their research, which also represents the
first demonstration of how radioactive sodium can be used as a tool in
nuclear forensics, appears in the current issue of ACS' Analytical
Chemistry, a semi-monthly journal.
In the new study, Jon Schwantes and colleagues note
increased concern about the possibility of terrorists smuggling
radioactive materials to make illegal nuclear weapons. As a result,
scientists are stepping up efforts to identify and track the source of
these radioactive materials using the advanced tools and techniques of
a new field called "nuclear archaeology."
The scientists describe efforts to determine the
origin of an unknown sample of plutonium (Pu) found in 2004 in a
bottle at a waste burial trench at the Hanford nuclear site in
Washington. Hanford is the earliest location for U.S. plutonium
production for nuclear weapons and now the focus of a massive
environmental cleanup effort due to high levels of radioactive waste
that remain at the site.
Using multiple pairs of "parent" Pu and "daughter"
uranium (U) isotopes, the researchers were able to correct for
chemical fractionation that occurred as a result of repackaging in
2004 and determine the age of the sample. Using this technique, they
estimated that the Pu in the sample had been separated from U and
fission products in 1944, making it the oldest known sample of
bomb-grade plutonium produced in a reactor. The only older known
samples of Pu-239 were produced by the late Glenn Seaborg and his
associates in the beginning of the 1940's when the existence of the
element was first confirmed and characterized.
The study identified the Clinton reactor in Oak
Ridge, Tenn., as reactor of origin for this material, by comparing
reactor burnup modeling results with measurements of minor Pu isotopes.
These results were also supported by a series of historical documents
tracking the material's movement from Oak Ridge and the processing at
Hanford. "Aside from the historical significance of this find, this
work provides the public a rare glimpse at a real-world example of the
science behind and power of modern-day nuclear forensics," the
scientists note. - MTS
"Silver nanoparticle" microscope may shed new
light on cancer, bone diseases
In a finding that could help speed the
understanding of diseases ranging from cancer to osteoporosis,
researchers in Utah are reporting development of a new microscope
technique that uses "silver nanoparticle" mirrors to reveal hidden
details inside bones, cancer cells, and other biological structures.
The method also can help identify structural damage in a wide variety
of materials, including carbon-fiber plastics used in airplanes, the
researchers say. Their study is scheduled for the March issue of ACS'
Nano Letters, a monthly journal.
In the new study, John Lupton and colleagues point
out that one of the most powerful, widely used tools for imaging
hidden biological structures is fluorescence microscopy, which
requires the specimen to be treated with fluorescent dyes or stains.
But the dyes used to visualize the structures can kill living cells,
limiting the effectiveness of the technique, the researchers note.
The scientists improved on this technique by using
an infrared laser to excite clusters of silver nanoparticles, each
about 1/5000th the width of a human hair, placed below the material
being studied. The particles focus intense beams of light up through
the sample to reveal information about the composition and structure
of the substance examined, the scientists say. In laboratory studies,
they used the new technique to view the iridescent green scales of the
so-called "photonic beetle," whose scales may provide clues to
designing new, more powerful solar cells and computer chips, the
scientists say. - MTS
Super-thin carbon sheets poised to revolutionize
electronics
Super-thin films of carbon with exotic properties,
now taking the scientific world by storm, may soon mean a new era of
brighter, faster, and smaller computers, smart phones, and other
consumer electronics. Brighter digital displays that flex like a sheet
of paper. Faster computer chips. Smaller computers. That's the word
from an article scheduled for the March 2 issue of Chemical &
Engineering News, ACS' weekly newsmagazine
In the magazine's cover story, C&EN Senior Editor
Mitch Jacoby notes that these so-called graphene sheets - 50,000 times
thinner than the width a single human hair - were first isolated by
researchers just a few years ago. The nano-size sheets perform better
than life-size carbon, with higher strength and the ability to conduct
electricity faster. These properties make them attractive for
developing new and improved electronic devices, the article notes.
Scientists in academia and industry have stepped up
their efforts to improve the performance and manufacture of graphene
sheets. At least one company plans to produce the sheets on an
industrial scale in ton quantities. Scientists had predicted the
existence of these unusual carbon sheets just a few years ago but had
not produced actual thin-films until recently. "Graphene is one of the
hottest topics in materials science these days," says one authority in
the C&EN article.
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