October 27, 2006, 9:27 PM CT

Vitamin C and Water Healthy for Plastics, Too

Two new laboratory breakthroughs are poised to dramatically improve how plastics are made by assembling molecular chains more quickly and with less waste. Using such environmentally friendly substances as vitamin C or pure water, the two approaches present attractive alternatives to the common plastic manufacturing technique called free radical polymerization (FRP).

"The methods both present novel and complementary ways to dramatically improve efficiency, product control, and cost for the polymer industry," said Andy Lovinger, the National Science Foundation program director who oversees funds for the two projects. "Each of these approaches could have a very significant impact on polymer manufacturing".

Plastics are polymers, long, potentially complex, molecule chains crafted from an array of smaller chemical units. Using FRP, chemical engineers can create the right plastic for a range of applications, such as a specific trim for a car door or soft foam for a pillow.

For some plastics, the building-block molecules do not easily link together. To surmount this problem, scientists from Carnegie Mellon University in Pittsburgh, Pa., devised a process called atom transfer radical polymerization (ATRP), which provides creative ways to coax the chemical subunits into chains. However, this method comes with certain costs, such as the need for a copper catalyst that can become unwanted waste.........

Posted by: Sarah      Permalink         Source

October 26, 2006, 4:46 AM CT

World's Most Intense Thunderstorms

A summer thunderstorm often provides much-needed rainfall and heat wave relief, but others bring large hail, destructive winds, and tornadoes. Now with the help of NASA satellite data, researchers are gaining insight into the distribution of such storms around much of the world.

By using data from the NASA Tropical Rainfall Measuring Mission (TRMM) satellite, scientists identified the regions on Earth that experience the most intense thunderstorms. Their study was reported in the August 2006 issue of the Bulletin of the American Meteorological Society. The strongest storms were found to occur east of the Andes Mountains in Argentina, where warm, humid air often collides with cooler, drier air, similar to storms that form east of the Rockies in the United States. Surprisingly, some semi-arid regions have powerful storms, including the southern fringes of the Sahara, northern Australia, and parts of the Indian subcontinent. In contrast, rainy areas such as western Amazonia and Southeast Asia experience frequent storms, but relatively few are severe. Northern Pakistan, Bangladesh, and parts of Central Africa also experience intense thunderstorms.

"TRMM has given us the ability to extend local knowledge about storms to a near-global reach," said lead author Edward Zipser, University of Utah, Salt Lake City. "In addition to containing the only precipitation radar in space, TRMM's other instruments provide a powerful overlap of data that is extremely useful for studying storms".........

Posted by: Tyler      Permalink         Source

October 24, 2006, 8:43 PM CT

A Supersolid Not Quite So Super?

A deceptively simple experiment, recently reported in the journal Science, has moved physics one step closer to explaining the odd behavior of supersolid helium. The unusual state of matter - in which a portion of the atoms are able to flow through a solid crystal with no resistance - was predicted as early as 1969 but not observed until recently.

In 2004, Eunsong Kim and Moses Chan from Penn State University published the first experimental evidence that the predicted behavior could actually be demonstrated in the laboratory. In the last two years, a flurry of papers attempted to clarify under what conditions the behavior emerges. So when Humphrey Maris, a professor of physics at Brown University, visited colleagues Satoshi Sasaki and Sebastien Balibar at l'Ecole Normale Superieure in Paris, they decided they needed to plan an experiment that could shed some new light on the problem.

"We were trying to think of an easy way to do something on superfluid solids," said Maris. "The idea of something flowing through something solid is pretty weird, isn't it? That's what we like about it".

Maris and company hatched an elegant plan that uses kitchen table physics to examine the behavior of this strange new state of matter. To understand how they probed the phenomenon, try this simple experiment. Fill a drinking straw with water and cover it with your finger. Place it in a glass of water. As long as your finger seals the straw, the water won't flow out into the cup. As soon as you release your finger, it does. The water doesn't flow out of the straw until you open a path that allows air to replace it.........

Posted by: Sarah      Permalink         Source

October 22, 2006, 8:47 PM CT

Portable 'lab on a chip'

Testing soldiers to see if they have been exposed to biological or chemical weapons could soon be much faster and easier, thanks to MIT researchers who are helping to develop a tiny diagnostic device that could be carried into battle.

By tweaking the design of a tiny pump, researchers affiliated with MIT's Institute for Soldier Nanotechnologies have taken a major step towards making an existing miniature "lab on a chip" fully portable, so the tiny device can perform hundreds of chemical experiments in any setting.

"In the same way that miniaturization led to a revolution in computing, the idea is that miniature laboratories of fluid being pumped from one channel to another, with reactions going on here and there, can revolutionize biology and chemistry," says Martin Bazant, associate professor of applied mathematics and leader of the research team.

Within the lab on a chip, biological fluids such as blood are pumped through channels about 10 microns, or millionths of a meter, wide. (A red blood cell is about 8 microns in diameter.) Each channel has its own pumps, which direct the fluids to certain areas of the chip so they can be tested for the presence of specific molecules.

Until now, scientists have been limited to two approaches to designing labs on a chip, neither of which offer portability. The first is to mechanically force fluid through microchannels, but this requires bulky external plumbing and scales poorly with miniaturization.........

Posted by: Sean      Permalink         Source

October 22, 2006, 8:23 PM CT

Subatomic Quick-change Artist

It's taken 19 long years of painstaking, high-precision experiments, but it's finally official: Physicists have announced the observation of a subatomic particle known as the Bs (pronounced "B sub s") meson switching between matter and antimatter states at a mind-boggling 3 trillion times per second.

The work could lead to a better understanding of the early universe, in which these particles were present in great abundance. It will also help physicists refine different theoretical models in high-energy physics.

Christoph Paus, associate professor of physics at MIT, led the analysis of years' worth of data from the world's highest-energy particle accelerator. Representing the 700-member team of the Collider Detector at Fermilab (CDF) collaboration, Paus presented the discovery to the scientific community Sept. 22 at the Fermi National Accelerator Laboratory in Illinois.

"The CDF result is an exquisite example of precision measurements extracting a small and subtle effect from nature," said Richard G. Milner, professor of physics and director of MIT's Laboratory for Nuclear Science (LNS). "The MIT group under the leadership of Christoph Paus, and with the strong support of the U.S. Department of Energy Office of High Energy Physics, the MIT Department of Physics and the MIT School of Science, constructed a key detector that was essential to this measurement".........

Posted by: Sarah      Permalink         Source

October 22, 2006, 8:00 PM CT

Entanglement Of Atom Pairs

Physicists at the Commerce Department's National Institute of Standards and Technology (NIST) have taken a significant step toward transforming entanglement-an atomic-scale phenomenon described by Albert Einstein as "spooky action at a distance"-into a practical tool. They demonstrated a method for refining entangled atom pairs (a process called purification) so they can be more useful in quantum computers and communications systems, emerging technologies that exploit the unusual rules of quantum physics for pioneering applications such as "unbreakable" data encryption.

The NIST work, published in the Oct. 19, 2006, issue of Nature,* marks the first time atoms have been both entangled and subsequently purified; previously, this process had been carried out only with entangled photons (particles of light). The NIST demonstration also is the first time that researchers have been able to purify particles nondestructively. Direct measurement would destroy the delicate entangled state of atom pairs; the new experiment gets around this problem by entangling two pairs of atoms and measuring only one pair.

Entanglement is a curious property of quantum physics that links the condition and behavior of two or more particles, such as atoms or photons. Entanglement can occur spontaneously when two atoms interact. For the initial interaction, the atoms have to be in close proximity, but the entanglement may persist even if they are physically moved apart. The quality of the entanglement can be degraded by a number of environmental factors, such as fluctuating magnetic fields, so the process and the transport of entangled particles need to be tightly controlled in technological applications. The purification process implemented at NIST can clean up or remove any distortions or "noise" regardless of the source by processing two or more noisy entangled pairs to obtain one entangled pair of higher purity.........

Posted by: Sarah      Permalink         Source

October 22, 2006, 7:55 PM CT

Fossilized Liquid Assembly

From a butterfly's iridescent wing to a gecko's sticky foot, nature derives extraordinary properties from ordinary materials like wax and keratin. Its secret is hierarchical topology: macroscale structures assembled from microscale components of varying sizes. Borrowing a page from nature's playbook, scientists at the National Institute of Standards and Technology (NIST) have developed a novel platform for the self-assembly of experimental hierarchical surfaces in a fluid. Their work offers diverse industries a new way to generate and measure self-assembly at the nano-scale.

A butterfly's wings shimmer because light plays upon tiny rows of scales, like tiles on a Spanish roof. The gecko sticks to surfaces because its feet are patterned with microscopic hairs, each hair tipped with hundreds of even tinier projections. Beads of water roll off the lotus's leaf because its surface is streaked with microscopic peaks, each with a finer structure, that makes the surface "super hydrophobic." These enhanced properties-other possibilities include super adhesion and low friction-have attracted the attention of design engineers for applications from bioengineered tissues to photonic crystals to submarines that slice through water with minimal drag.

Creating these topologically complex, self-assembled surfaces for study has been a challenge. If the components are mixed on a surface, that substrate affects how they assemble; if mixed in a solvent and dried, the drying process similarly distorts the results. In a recent paper*, the NIST team detailed a much simpler and faster system they dubbed "fossilized liquid assembly" to create experimental models of hierarchical topologies in which the components are allowed to mix and assemble freely in a fluid, and then quickly "frozen" in place for study. The key is the use of solutions of water and a special monomer that polymerizes-links together-when exposed to ultraviolet light. Like an oil-water mixture, the fluid forms liquid interfaces that can be manipulated to create a desired hierarchical structure and then suddenly solidified with a burst of UV light.........

Posted by: Kevin      Permalink         Source

October 22, 2006, 7:46 PM CT

SRM Can Help Control Heavy Metal Content

A new reference material developed by the National Institute of Standards and Technology (NIST) can help the agriculture industry and state regulators monitor the concentrations of several potentially hazardous heavy metal contaminants in fertilizers.

Modern multi-nutrient fertilizers produced for home and agricultural use are formulated from multiple sources to provide significant amount of nitrogen, phosphorus and potassium, the major plant nutrients, and lesser or even trace amounts of other nutrients needed by different crops, such as boron, calcium, iron and zinc.

Until relatively recently, fertilizers were tested and certified for their nutrient content, but little attention was paid to the possibility of heavy metal contaminants introduced by the mineral sources used to prepare the fertilizer. However, in response to incidents of heavy metal contamination of cropland, several states have enacted regulations in the past seven years that limit the amounts of some potentially hazardous non-nutritive elements in fertilizers. Several countries, including Japan, China, and Australia, and the European Union, also limit the amount of selected elements in fertilizers.

While fertilizer manufacturers and state regulatory authorities have needed to develop analytical methods to implement these regulations, until now there have been no certified reference materials available that they could use to validate the accuracy of their measurements. It can be difficult to measure accurately trace levels of some metals in a chemically complex mixture like fertilizer.........

Posted by: Kevin      Permalink         Source

October 19, 2006, 9:21 PM CT

Fusion In The Fast Lane

Using fast digital imaging, researchers from the Max Planck Institute of Colloids and Interfaces in Potsdam, Gera number of, together with scientists from Collge de France, have succeeded in developing two different protocols by which one can initiate the fusion process in a controlled manner and observe the subsequent fusion dynamics with a temporal resolution in the microsecond regime. For both protocols, the opening of the fusion necks was found to be very fast, with an average expansion velocity of centimetres per second. This velocity indicates that the initial formation of a single fusion neck can be completed in a few hundred nanoseconds. (Proceedings of the National Academy of Sciences of the USA 103, 15841-15846, October 24, 2006).

The process of membrane fusion is essential for the structure and dynamics of all cells in our bodies. Fusion is indispensable for intracellular vesicle traffic, which sustains the compartmental organisation of cells. Likewise, membrane fusion is the basic molecular process that controls the communication between cells via the secretion of hormones, neurotransmitters, and growth factors. Furthermore, fusion processes are also crucial for the interactions between our cells and various pathogens such as viruses and bacteria. However, in spite of the ubiquity of membrane fusion, a number of aspects of this process have remained rather controversial. This situation reflects the absence of well-defined protocols by which one can induce fusion in a controlled manner and subsequently study its dynamics with high temporal resolution.........

Posted by: Kevin      Permalink         Source

October 19, 2006, 9:01 PM CT

Affymetrix 500K Array And Memory Gene

Affymetrix Inc. announced recently that researchers at the Translational Genomics Research Institute (TGen) in Phoenix, Arizona have used the Affymetrix 500K Array to discover a gene--called Kibra--associated with memory performance in humans. The team's findings may be used to develop new medicines for memory-based diseases such as Alzheimer's and Parkinson's by providing scientists with a better understanding of how memory works at the molecular level.

The study entitled, "Common KIBRA alleles are associated with human memory performance," would be published in the Oct. 20, 2006 issue of Science. The research team was led by Dietrich Stephan, Ph.D., director of TGen's Neurogenomics Division. It included colleagues at the University of Zurich in Switzerland, Banner Alzheimer's Institute and Mayo Clinic Scottsdale.

"Using the latest Affymetrix 500K Array, we have shed light on the fundamental biological process of human memory performance," said Dr. Stephan. "We can use this new understanding to develop drugs that will improve memory function".

Until now, researchers did not have access to the high-density technology needed to examine the genetic components associated with memory performance. The team at TGen used Affymetrix Human Mapping 500K Arrays to analyze 500,000 DNA markers simultaneously, providing a genetic blueprint for the memory-study participants. The researchers discovered the Kibra gene by comparing the genetic blueprints of people with good memory vs. poor memory and looking for the genetic variations consistently present in one group, but not the other. They then validated their discovery by replicating the Kibra gene finding in two separate and distinct groups of subjects.........

Posted by: Kevin      Permalink         Source