October 24, 2006, 6:10 PM CT

Electronic Chip Interacting With The Brain

Scientists at the University of Washington (UW) are working on an implantable electronic chip that may help establish new nerve connections in the part of the brain that controls movement. Their most recent study, would be reported in the Nov. 2, 2006, edition of Nature, showed such a device can induce brain changes in monkeys lasting more than a week. Strengthening of weak connections through this mechanism may have potential in the rehabilitation of patients with brain injuries, stroke, or paralysis.

The authors of study, titled "Long-Term Motor Cortex Plasticity Induced by an Electronic Neural Implant," were Dr. Andrew Jackson, senior research fellow in physiology and biophysics, Dr. Jaideep Mavoori, who recently earned a Ph.D. in electrical engineering from the UW, and Dr. Eberhard Fetz, professor of physiology and biophysics. For a number of years Fetz and colleagues have studied how the brains of monkeys control their limb muscles.

When awake, the brain continuously governs the body's voluntary movements. This is largely done through the activity of nerve cells in the part of the brain called the motor cortex. These nerve cells, or neurons, send signals down to the spinal cord to control the contraction of certain muscles, like those in the arms and legs.........

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October 22, 2006, 10:58 PM CT

Excalia Combination Therapy To Treat Obesity

OREXIGEN^TM Therapeutics, Inc., a privately held clinical-stage neuroscience company developing novel strategic approaches to the therapy of obesity, today announced that Excalia^TM, a combination of two centrally-acting medications intended to provide and sustain clinically important weight loss, demonstrated significant weight loss in a six month, double-blind, phase IIa clinical study. The magnitude of weight reduction exceeded that seen with placebo. The findings showed that patients completing the blinded 24-week phase lost on average 9.2% of their weight from baseline using Excalia in comparison to an average of 0.4% weight loss from baseline for patients using placebo. The study results further demonstrate that weight loss continued through an additional 24 week open-label period achieving an average weight loss of 12% from baseline by 48 weeks. These top line phase IIa data for Excalia were presented at the annual meeting of the North American Association for the Study of Obesity (NAASO) in Boston.

"Excalia is designed to achieve an aggressive weight loss trajectory and then to delay the typical weight loss 'plateau' by offsetting one of the body's natural compensatory pathways. These phase II data suggest a level of efficacy that exceeded our expectations in relation to existing approaches," said Gary Tollefson, M.D., Ph.D., OREXIGEN president and CEO. "Excalia is designed to act on a specific reciprocally paired group of hypothalamic neurons that we believe will yield a clinically meaningful weight loss trajectory among significantly overweight individuals. We think that these positive data support our theoretical approach".........

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October 22, 2006, 8:48 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 scientists who are helping to develop a tiny diagnostic device that could be carried into battle.

By tweaking the design of a tiny pump, scientists 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, researchers 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.........

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October 22, 2006, 8:33 PM CT

Smoking Impedes Healing

Orthopaedic surgery scientists at Washington University School of Medicine in St. Louis have identified yet another reason not to smoke. Studying rotator cuff injury in rats, the research team found exposure to nicotine delays tendon-to-bone healing, suggesting this could cause failure of rotator cuff repair following surgery in human patients.

Smoking is implicated in a host of physical problems, from cardiovascular disease to lung disorders. A number of of us probably don't think about smoking's effects on orthopaedic conditions, but several studies have shown that nicotine interferes with healing of bone fractures and also inhibits bone fusion processes - a number of spine surgeons, for example, won't do certain operations on people who smoke because of the risk of failure. But little is known about the effects of cigarettes on tendon and ligament healing.

There also are some gaps in medical knowledge about the prevalence of rotator cuff injuries. The rotator cuff is a group of four muscles and their tendons in the shoulder that provide rotation, elevate the arm and stabilize the shoulder joint. Rotator cuff tears involve one or more of the tendons. The injuries are more common as people age and more common in the dominant arm. The true occurence rate of the injuries is hard to determine because between 5 percent and 40 percent of people who may have a torn rotator cuff have no accompanying shoulder pain.........

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October 22, 2006, 8:24 PM CT

2.8 Trillion Times Per Second

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".........

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October 22, 2006, 7:56 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, researchers 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.........

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October 22, 2006, 7:50 PM CT

Molecular Spintronic Action In Nanostructure

Researchers at the National Institute of Standards and Technology (NIST) have made the first confirmed "spintronic" device incorporating organic molecules, a potentially superior approach for innovative electronics that rely on the spin, and associated magnetic orientation, of electrons. The physicists created a nanoscale test structure to obtain clear evidence of the presence and action of specific molecules and magnetic switching behavior.

Whereas conventional electronic devices depend on the movement of electrons and their charge, spintronics works with changes in magnetic orientation caused by changes in electron spin (imagine electrons as tiny bar magnets whose poles are rotated up and down). Already used in read-heads for computer hard disks, spintronics can offer more desirable properties-higher speeds, smaller size-than conventional electronics. Spintronic devices usually are made of inorganic materials. The use of organic molecules may be preferable, because electron spins can be preserved for longer time periods and distances, and because these molecules can be easily manipulated and self-assembled. However, until now, there has been no experimental confirmation of the presence of molecules in a spintronic structure. The new NIST results are expected to assist in the development of practical molecular spintronic devices.........

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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.........

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October 19, 2006, 9:22 PM CT

Fusion In The Fast Lane

Using fast digital imaging, scientists from the Max Planck Institute of Colloids and Interfaces in Potsdam, Germany, together with researchers 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, many 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.........

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October 19, 2006, 9:08 PM CT

Hyper-Cest MRI And Molecular Imaging

Researchers with the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California at Berkeley have developed a new technique for Magnetic Resonance Imaging (MRI) that allows detection of signals from molecules present at 10,000 times lower concentrations than conventional MRI techniques. Called HYPER-CEST, for hyperpolarized xenon chemical exchange saturation transfer, this new technique holds great promise for molecular imaging, in which the spatial distribution of specific molecules is detected within an organism. Ultimately, HYPER-CEST could become a valuable tool for medical diagnosis, including the early detection of cancer.

In a paper published in the October 20, 2006 issue of the journal Science, the team of researchers report on a technique in which xenon atoms that have been hyperpolarized with laser light to enhance their MRI signal, incorporated into a biosensor and linked to specific protein or ligand targets. These hyperpolarized xenon biosensors generate highly selective contrast at sites where they are bound, dramatically boosting the strength of the MRI signal and resulting in spatial images of the chosen molecular or cellular target.

This research was led by Alexander Pines and David Wemmer, who both hold joint appointments with Berkeley Lab and UC Berkeley. Their paper is entitled Molecular Imaging Using a Targeted Magnetic Resonance Hyperpolarized Biosensor. Co-authoring the paper with Pines and Wemmer were Leif Schroder and Thomas Lowery, plus Christian Hilty.........

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