Edible nanostructures:
Compounds made from renewable materials could be used for gas storage, food technologies.
Sugar, salt, alcohol and a little serendipity led a Northwestern University research team to discover a new class of nanostructures that could be used for gas storage and food and medical technologies. And the compounds are edible
[Image credit: Angewandte Chemie, DOI 10.1002/anie.201002343].
Listen up! U-M experiment records ultrafast chemical reaction with vibrational echoes.
The molecules shown here in yellow are first-hand observers to an ultrafast chemical reaction.
As the reaction proceeds, the vibrational frequencies of the yellow
molecules change ...
Chemists at Indiana University Bloomington have
designed a molecule that binds chloride ions - but can be
conveniently compelled to release the ions in the presence of
ultraviolet light[Image credit: Amar Flood].
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More News (open access):
Best way to pour champagne? 'Down the side' wins
first scientific test
In a study that may settle a long-standing
disagreement over the best way to pour a glass of champagne,
scientists in France are reporting that pouring bubbly in an angled,
down-the-side way is best for preserving its taste and fizz. The study
also reports the first scientific evidence confirming the importance
of chilling champagne before serving to enhance its taste, the
scientists say. Their report appears in ACS' bi-weekly Journal of
Agricultural and Food Chemistry.
Gerard Liger-Belair and colleagues note that tiny
bubbles are the essence of fine champagnes and sparkling wines. Past
studies indicate that the bubbles - formed during the release of large
amounts of dissolved carbon dioxide gas - help transfer the taste,
aroma, and mouth-feel of champagne. Scientists long have suspected
that the act of pouring a glass of bubbly could have a big impact on
gas levels in champagne and its quality. Until now, however, no
scientific study had been done.
The scientists studied carbon dioxide loss in
champagne using two different pouring methods. One involved pouring
champagne straight down the middle of a glass. The other involved
pouring champagne down the side of an angled glass. They found that
pouring champagne down the side preserved up to twice as much carbon
dioxide in champagne than pouring down the middle - probably because
the angled method was gentler. They also showed that cooler champagne
temperatures (ideally, 39 degrees Fahrenheit) help reduce carbon
dioxide loss.
Toward safer plastics that lock in potentially
harmful plasticizers
Scientists have published the first report on a new
way of preventing potentially harmful plasticizers from migrating from
one of the most widely used groups of plastics. The advance could lead
to a new generation of polyvinyl chloride (PVC) plastics that are
safer than those now used in packaging, medical tubing, toys, and
other products, they say. Their study is in ACS' Macromolecules, a
bi-weekly journal.
Helmut Reinecke and colleagues note that
manufacturers add large amounts of plasticizers to PVC to make it
flexible and durable. Plasticizers may account for more than one-third
of the weight of some PVC products. Phthalates are the mainstay
plasticizers. Unfortunately, they migrate to the surface of the
plastic over time and escape into the environment. As a result, PVC
plastics become less flexible and durable. In addition, people who
come into contact with the plastics face possible health risks. The U.
S. Consumer Product Safety Commission in 2009 banned use of several
phthalate plasticizers for use in manufacture of toys and child care
articles.
The scientists describe development of a way to
make phthalate permanently bond, or chemically attach to, the internal
structure of PVC so that it will not migrate. Laboratory tests showed
that the method completely suppressed the migration of plasticizer to
the surface of the plastic. "This approach may open new ways to the
preparation of flexible PVC with permanent plasticizer effect and zero
migration," the article notes.
Oil-eating bacteria may determine environmental
impact of Gulf oil
The environmental impact of millions of gallons of
oil still in the Gulf of Mexico from the Deepwater Horizon incident
may depend on microscopic helpers: Bacteria that consume oil and other
hydrocarbons and could break down the spilled crude, making it
disappear. That's the topic of an article in the current issue of
Chemical & Engineering News (C&EN), ACS' weekly newsmagazine.
It points out that the oil-eating bacteria are
beneficial in helping to clear away the oil. Their activity, however,
could eventually pose risks to the Gulf's ecosystem, particularly in
the deep ocean. The oil acts as a huge source of food and could
produce bacteria "blooms," or massive population explosions. As the
blooms die and decay, they remove oxygen from the Gulf water,
jeopardizing the health of fish and other aquatic animals.
The article discusses scientific research underway
to shed light on the bacteria's effects. It notes that the oxygen
depletion so far is not as serious as the Gulf of Mexico's infamous
"dead zone," an 8,000 square mile area - about the size of New Jersey
- with oxygen levels too low for fish to survive. The Gulf's oil
plumes cause nearly a 35 percent oxygen drop compared to a 90 percent
drop in that dead zone.
Chemical & Engineering News: "Microbes
to the Rescue" [Volume 88, Number 32pp. 32 - 33; DOI:
10.1021/CEN080210163345].
Deathstalker scorpion venom could improve gene
therapy for brain cancer
An ingredient in the venom of the "deathstalker"
scorpion could help gene therapy become an effective treatment for
brain cancer, scientists are reporting. The substance allows
therapeutic genes - genes that treat disease - to reach more brain
cancer cells than current approaches, according to the study in ACS
Nano, a monthly journal.
Miqin Zhang and colleagues note that gene therapy -
the delivery of therapeutic genes into diseased cells - shows promise
for fighting glioma, the most common and most serious form of brain
cancer. But difficulties in getting genes to enter cancer cells and
concerns over the safety and potential side effects of substances used
to transport these genes have kept the approach from helping patients.
The scientists describe a new approach that could
solve these problems. Key ingredients of their gene-delivery system
are chlorotoxin, the substance in deathstalker scorpion venom that can
slow the spread of brain cancer, and nanoparticles of iron oxide. Each
nanoparticle is about 1/50,000th the width of a human hair. In tests
on lab mice, the scientists demonstrated that their venom-based
nanoparticles can induce nearly twice the amount of gene expression in
brain cancer cells as nanoparticles that do not contain the venom
ingredient. "These results indicate that this targeted gene delivery
system may potentially improve treatment outcome of gene therapy for
glioma and other deadly cancers," the article notes.
This skin tumor is shown after
treatment with a new contrast agent that can improve the
visualization of skin cancer cells using an advanced medical
imaging device.
Credit: American Chemical Society
Scientists are reporting development of a substance
to enhance the visibility of skin cancer cells during scans with an
advanced medical imaging system that combines ultrasound and light.
The hybrid scanner could enable doctors to detect melanoma, the most
serious form of skin cancer, in its earliest and most curable stages,
the report in the monthly journal ACS Nano indicates.
Lihong Wang, Younan Xia, and colleagues point out
that early diagnosis is key to improving survival in patients with
melanoma. The five-year survival rate for melanoma is about 98 percent
if detected early but can be as low as 15 percent when detected at an
advanced stage. Existing imaging techniques for early detection of
melanoma produce low-quality images, can "see" only a fraction of an
inch below the skin, and use potentially harmful radioactive
materials. A promising new technique called photoacoustic tomography
(PAT) can overcome these problems. The system shoots light into
tumors, which slightly heats up the cancer cells and produces high
frequency sound waves that provide images of the tumor. But the PAT
system lacks an optimal contrast agent that can easily enter skin
cancer cells and make them visible.
The scientists developed such an agent by attaching
a peptide (one of the building blocks of proteins) that targets skin
cancer cells to gold "nanocages." These hollow gold nanoparticles have
a box-like shape and are barely 1/50,000th the width of a human hair.
When injected into mice with skin cancer, the nanocages improved the
image quality of the cancer cells by three-fold compared to
nanoparticles lacking the peptide. The gold nanocages also show
promise as a way to kill skin cancer cells using heat or anti-cancer
drugs, they add.
X-ray fluorescence spectroscopy unveils Da Vinci’s astounding sfumato technique.
Image:
Non-invasive X-ray fluorescence spectroscopy was used to reveal the sfumato paint layer stacking method that was used by Leonardo da Vinci to paint the faces in seven of his paintings.
InChI makes chemical structural formulae on the Internet visible to all search engines.
Image: An InChI is a character string of letters,
numbers and symbols; the InChIKey is a pure text string, which can be
processed very easily by search engines.
Study of electron orbits in multilayer graphene finds unexpected energy gaps.
This graphic shows electrons that move along an
equipotential, while those that follow closed
equipotentials (as in a potential-energy valley)
become localized (right).
For the first time ever, physicists from
the Laboratory for Attosecond Physics (LAP) at the Max
Planck Institute of Quantum Optics have observed what occurs
inside an atom from which a single electron has been
ejected.
Figure: A sequence of snapshots showing the oscillatory motion of a valence electron inside an atomic ion, as reconstructed from attosecond measurements [Courtesy of Dr. Christian Hackenberger, Ludwig-Maximillians University, Munich, Germany].
Individual molecules and their dynamics can also be made visible in living cells using conventional fluorophores at a resolution of around 20 nanometers.
How this is done is being revealed for the first time by researchers from Würzburg, Bielefeld, and New York in the journal Nature Methods.
Help from the dark side: Using dark channel fluorescence, scientists can explain how biochemical substances carry out their function.
Image:
X-ray photon taking electron from the Fe(III) active center to the water mixed orbital in time scale faster than 7 femtoseconds (the core-hole life time of Fe(III).
[Credit: Helmholtz-Zentrum Berlin für Materialien und Energie, HZB]
Direct potentiometric determination of the sialic acid concentration on cell surfaces - a new technique for tumor diagnosis?
Image: A self-assembled phenylboronic acid
monolayer on the surface of a gold electrode enabled the potentiometric
detection of cell-membrane sialic acidand
differentiation of healthy pneumocytes from metastatic melanoma cells on
the basis of altered SA expression.
[Credit: Angewandte Chemie, DOI 10.1002/anie.201001220]
Materials for tomorrow's nanoelectronics: scientists reported in Nature how they have managed for the first time to grow graphene ribbons that are just a few nanometres wide using a simple surface-based chemical method.
Image:
This is a structural model and three-dimensional picture of the scanning tunneling microscope view of a zig-zag shaped graphene nanoribbon. [Credit: EMPA].
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Chemistry & Nanotechnology
MRSA Killing
Coating
Rensselaer Polytechnic Institute researchers develop coating
that safely kills MRSA on contact.
'Microfluidic palette' may paint clearer picture of biological processes.
Image:
This is the NIST microfluidic palette. The mixing area is the pin-sized chamber bordered by three holes in the center of the top layer [Image by G. Cooksey, NIST].
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].
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Chemistry & Environment
Mosquito-free
Mother Nature to provide an environmentally friendly method for reducing mosquitoes.
Rates of Photosynthesis and Ecosystem Respiration
A new balance for the global carbon balance: Researchers determine how rates of photosynthesis and ecosystem respiration depend on the climate in order to obtain a better assessment of the consequences of climate change.
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.
A 150-million-year old 'dinobird' fossil, long thought to contain nothing but fossilized bone and rock, has been hiding remnants of the animal's original chemistry, according to new research.
Abiotic Nitrous Oxide Emission
Research in Antarctica reveals non-organic mechanism for production of important greenhouse gas.
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