Discovery supports development of nanoscale magnetic storage devices.
[Image courtesy Saw-Wai Hla, Ohio University]
Graphene
What projections and humps can be good for: Investigators measure how the electronic properties of graphene can be controlled with purposefully used roughnesses.
Antimony in the Environment
A different kind of mine disaster: The world's largest antimony mine has become the world's largest laboratory for studying the environmental consequences of escaped antimony - an element whose environmental and biological properties are still largely a mystery.
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Chemistry & Geology
Abiotic Nitrous Oxide Emission
Research in Antarctica reveals non-organic mechanism for production of important greenhouse gas.
Ultrasensitive Imaging Method Uses Gold-silver Nanocages
New research findings suggest that an experimental ultrasensitive medical imaging technique that uses a pulsed laser and tiny metallic "nanocages" might enable both the early detection and treatment of disease.
Fuel Cells Get Up to Speed with a New Kind of Platinum
A new form of platinum that could be used to make cheaper, more efficient fuel cells has been created by researchers at the Department of Energy's SLAC National Accelerator Laboratory and the University of Houston.
Plastic Money
Australia?s plastic bills make life difficult for counterfeiters.
Large, Solution-Processable Graphene Quantum Dots as Light Absorbers for Photovoltaics.
The picture shows a 2-D view of a graphene sheet (black) and attached sidegroups (blue) that IU Bloomington chemist Liang-shi Li and his collaborators devised
[Credit: Image by Liang-shi Li].
Propylene Oxide Production
Scientists develop environmentally friendly way to produce propylene oxide using silver nanoclusters.
Lightweight Batteries
MIT makes significant step toward lightweight batteries. Research shows metal catalysts play important role in improving efficiency.
Little melamine appears in eggs from chickens on
highly contaminated
Chickens that eat high levels of
melamine in their feed still produce eggs that contain low levels
of the potentially toxic contaminant.
[Credit: iStock]
Eggs from chickens that consumed extremely high
levels of melamine in their feed still did not contain levels of the
potentially toxic contaminant that exceeded U. S. Food and Drug
Administration (FDA) limits. That was the conclusion of the first
study to check on the effects of melamine-contaminated feed in laying
hens. It appears in ACS' Journal of Agricultural and Food Chemistry, a
bi-weekly publication.
Liying Zhang and colleagues note that melamine,
which is used to make certain plastics, triggered a public health
controversy in 2008 because certain food manufacturers in China
illegally added it to milk powder to distort the protein content.
Authorities have since found excessive levels of melamine in eggs from
chickens eating feed contaminated with the substance. However,
scientists did not know how much melamine might accumulate in eggs
from this process, until now.
In an effort to establish a scientific basis for
determining the risk, Zhang's group gave melamine-contaminated feed to
egg-laying hens and found that increasing amounts of the chemical in
feed resulted in increasing amounts in the eggs. However, none of the
melamine concentrations in the eggs exceeded the FDA's maximum
allowable level - 2.5 parts per million (ppm) in foods. The highest
levels of melamine in the feed, about 100 ppm, resulted in egg
contamination levels of about 1.45 ppm. The scientists suggest that
melamine contamination levels in feed that fall below 100 ppm would
not result in potential hazards for food safety.
Solar panels, flexible displays,
and other futuristic electronics made with nanoparticles may
become more affordable thanks to a new method that recovers the
pricey particles for reuse.
[Credit: iStock]
Scientists are reporting first use of a new method
that may make it easier for manufacturers to recover, recycle, and
reuse nanoparticles, some of which ounce for ounce can be more
precious than gold. The method, which offers a solution to a nagging
problem, could speed application of nanotechnology in new generations
of solar cells, flexible electronic displays, and other products, the
scientists suggest. Their study appears in ACS' Langmuir, a bi-weekly
journal.
Julian Eastoe and colleagues point out that
scientists are seeking better ways to recover and reuse nanoparticles,
which are barely 1/50,000th the width of a human hair. Without that
technology, manufacturing processes that take advantage of
nanoparticles' unusual properties might be prohibitively expensive.
Recovering and recycling nanoparticles is especially difficult because
they tend to form complex, hard-to-separate mixtures with other
substances.
Eastoe and colleagues describe the development of a
special type of microemulsion - a mixture of oil and water (mayonnaise
is an edible emulsion) - that may solve this problem. In laboratory
tests using cadmium and zinc nanoparticles, they showed how the oil
and water in the microemulsion separated into two layers when heated.
One layer contained nanoparticles that could be recovered and the
other contained none. The separation process is reversible and the
recovered particles retain their shape and chemical properties, which
is crucial for their reuse, the scientists note.
The age of Aquarius? Nope, it's the Anthropocene
epoch
The geologic time scale might be
amended in the future to include a new period called the "Anthropocene
epoch" that is marked by stunning population growth and
unprecedented changes in human activity.
[Credit: US Geological Survey]
In just two centuries, humans have wrought such
vast and unprecedented changes to our world that we actually might be
ushering in a new geological time period that could alter the planet
for millions of years, according to a group of prominent scientists
that includes a Nobel Laureate. They say the dawning of this new epoch
could lead to the sixth largest mass extinction in the Earth's
history. Their commentary appears in ACS' bi-weekly journal
Environmental Science & Technology.
Jan Zalasiewicz, Mark Williams, Will Steffen, and
Paul Crutzen (the Nobel Prize-winning atmospheric chemist) reflect
that recent human activity, including stunning population growth,
sprawling megacities and increased use of fossil fuels, have changed
the planet to such an extent that we are entering what they call the
Anthropocene (New Human) epoch. The notion of such drastic human
influence was controversial for many years. However, as more potential
consequences of human activity - such as global climate change and
sharp increases in plant and animal extinction - have emerged. The
Anthropocene (a term proposed by Crutzen a decade ago) has gained
support. Currently, the worldwide geological community is considering
whether Anthropocene should join Jurassic, Cambrian and other more
familiar units on the Geological Time Scale.
Zalasiewicz, Crutzen and colleagues note that
getting that formal designation could be contentious. But they
conclude, "However these debates will unfold, the Anthropocene
represents a new phase in the history of both humankind and of the
Earth, when natural forces and human forces became intertwined, so
that the fate of one determines the fate of the other. Geologically,
this is a remarkable episode in the history of this planet."
Environmental Science & Technology: "The
New World of the Anthropocene" [Environ. Sci. Technol., 2010, 44
(7), pp 2228?2231; DOI: 10.1021/es903118j].
Household detergents, shampoos may form harmful
substance in waste water
Dishwashing detergent is among
the household cleaning products containing ingredients that could
form a cancer-causing contaminant in wastewater.
[Credit: iStock]
Scientists are reporting evidence that certain
ingredients in shampoo, detergents and other household cleaning agents
may be a source of precursor materials for formation of a suspected
cancer-causing contaminant in water supplies that receive water from
sewage treatment plants. The study sheds new light on possible
environmental sources of this poorly understood water contaminant,
called NDMA, which is of ongoing concern to health officials. Their
study is in ACS' Environmental Science & Technology, a semi-monthly
journal.
William Mitch and colleagues note that scientists
have known that NDMA and other nitrosamines can form in small amounts
during the disinfection of wastewater and water with chloramine.
Although nitrosamines are found in a wide variety of sources -
including processed meats and tobacco smoke - scientists know little
about their precursors in water. Past studies with cosmetics have
found that substances called quaternary amines, which are also
ingredients in household cleaning agents, may play a role in the
formation of nitrosamines.
Their laboratory research showed that when mixed
with chloramine, some household cleaning products - including shampoo,
dishwashing detergent and laundry detergent - formed NDMA. The report
notes that sewage treatment plants may remove some of quaternary
amines that form NDMA. However, quaternary amines are used in such
large quantities that some still may persist and have a potentially
harmful effect in the effluents from sewage treatment plants.
Toward a better dining experience: The emerging
science of molecular gastronomy
Novel food textures and flavor
combinations are among the promises of a new science called
molecular gastronomy, which may revolutionize the dining
experience at restaurants and homes.
[Credit: iStock]
A new and relatively little-known scientific
discipline called molecular gastronomy has quietly revolutionized the
dining experience in some famous restaurants and promises to foster a
wider revolution in other restaurant and home kitchens. That's the
conclusion of an article in ACS' Chemical Reviews, a monthly journal.
In the article, Peter Barham and colleagues present
a sweeping overview of molecular gastronomy, which focuses on the
science behind food preparation techniques, including the chemistry of
cooking. "Our basic premise is that the application of chemical and
physical techniques in some restaurant kitchens to produce novel
textures and flavor combinations has not only revolutionized the
restaurant experience but also led to new enjoyment and appreciation
of food," the scientists note. Examples include the restaurants El
Bulli in Spain and Fat Duck in the United Kingdom, which have become
regarded by some as among the finest in the world after adopting this
scientific approach to cooking.
The new science pays particular attention to the
conditions that underpin an individual's enjoyment of food, including
flavor levels in a food dish and even a diner's "frame of mind" for
enjoying a meal. The authors note that "we may be able to serve
different variants of the same dish to our dinner party guests so that
each has their own uniquely pleasing experience. If molecular
gastronomy can achieve such a goal, it will go a long way to changing
forever the public perception of chemistry."
Evidence that nanoparticles in sunscreens could be
toxic if accidentally eaten
Sunscreens contain nanoparticles
of zinc oxide - used to prevent the damaging effects of sunlight -
that can harm colon cells and may be toxic if accidentally eaten.
[Credit: iStock]
Scientists are reporting that particle size affects
the toxicity of zinc oxide, a material widely used in sunscreens.
Particles smaller than 100 nanometers are slightly more toxic to colon
cells than conventional zinc oxide. Solid zinc oxide was more toxic
than equivalent amounts of soluble zinc, and direct particle to cell
contact was required to cause cell death. Their study is in ACS'
Chemical Research in Toxicology, a monthly journal.
Philip Moos and colleagues note that there is
ongoing concern about the potential toxicity of nanoparticles of
various materials, which may have different physical and chemical
properties than larger particles. Barely 1/50,000 the width of a human
hair, nanoparticles are used in foods, cosmetics and other consumer
products. Some sunscreens contain nanoparticles of zinc oxide.
"Unintended exposure to nano-sized zinc oxide from children
accidentally eating sunscreen products is a typical public concern,
motivating the study of the effects of nanomaterials in the colon,"
the scientists note.
Their experiments with cell cultures of colon cells
compared the effects of zinc oxide nanoparticles to zinc oxide sold as
a conventional powder. They found that the nanoparticles were twice as
toxic to the cells as the larger particles. Although the nominal
particle size was 1,000 times larger, the conventional zinc oxide
contained a wide range of particle sizes and included material small
enough to be considered as nanoparticles. The concentration of
nanoparticles that was toxic to the colon cells was equivalent to
eating 2 grams of sunscreen - about 0.1 ounce. This study used
isolated cells to study biochemical effects and did not consider the
changes to particles during passage through the digestive tract. The
scientists say that further research should be done to determine
whether zinc nanoparticle toxicity occurs in laboratory animals and
people.
Consumers over age 50 should consider steps to cut
copper and iron intake
Copper from home plumbing is one
metal that may increase the risk of Alzheimer's disease and other
age-related disorders.
[Credit: Susan Lesch, Wikimedia
Commons]
With scientific evidence linking high levels of
copper and iron to Alzheimer's disease, heart disease, and other
age-related disorders, a new report in ACS' Chemical Research in
Toxicology suggests specific steps that older consumers can take to
avoid build up of unhealthy amounts of these metals in their bodies.
"This story of copper and iron toxicity, which I think is reaching the
level of public health significance, is virtually unknown to the
general medical community, to say nothing of complete unawareness of
the public," George J. Brewer states in the report.
The article points out that copper and iron are
essential nutrients for life, with high levels actually beneficial to
the reproductive health of younger people. After age 50, however, high
levels of these metals can damage cells in ways that may contribute to
a range of age-related diseases.
"It seems clear that large segments of the
population are at risk for toxicities from free copper and free iron,
and to me, it seems clear that preventive steps should begin now." The
article details those steps for people over age 50, including avoiding
vitamin and mineral pills that contain cooper and iron; lowering meat
intake: avoiding drinking water from copper pipes; donating blood
regularly to reduce iron levels; and taking zinc supplements to lower
copper levels.
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