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November 2006
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NIST laser-based method cleans up grubby nanotubes

Before carbon nanotubes can fulfill their promise as ultrastrong fibers, electrical wires in molecular devices, or hydrogen storage components for fuel cells, better methods are needed for purifying raw nanotube materials. Researchers at the National Institute of Standards and Technology (NIST) and the National Renewable Energy Laboratory (NREL, Golden, Colo.), have taken a step toward this goal by demonstrating a simple method of cleaning nanotubes by zapping them with carefully calibrated laser pulses.

When carbon nanotubes--the cylindrical form of the fullerene family--are synthesized by any of several processes, a significant amount of contaminants such as soot, graphite and other impurities also is formed. Purifying the product is an important issue for commercial application of nanotubes.


In a forthcoming issue of Chemical Physics Letters, the NIST/NREL team describes how pulses from an excimer laser greatly reduce the amount of carbon impurities in a sample of bulk carbon single-walled nanotubes, without destroying tubes. Both visual examination and quantitative measurements of material structure and composition verify that the resulting sample is "cleaner." The exact cleaning process may need to be slightly modified depending on how the nanotubes are made, the authors note. But the general approach is simpler and less costly than conventional "wet chemistry" processes, which can damage the tubes and also require removal of solvents afterwards.

"Controlling and determining tube type is sort of the holy grail right now with carbon nanotubes. Purity is a key variable," says NIST physicist John Lehman, who leads the research. "Over the last 15 years there's been lots of promise, but when you buy some material you realize that a good percentage of it is not quite what you hoped. Anyone who thinks they're going into business with nanotubes will realize that purification is an important--and expensive--step. There is a lot of work to be done."

The new method is believed to work because, if properly tuned, the laser light transfers energy to the vibrations and rotations in carbon molecules in both the nanotubes and contaminants. The nanotubes, however, are more stable, so most of the energy is transferred to the impurities, which then react readily with oxygen or ozone in the surrounding air and are eliminated. Success was measured by examining the energy profiles of the light scattered by the bulk nanotube sample after exposure to different excimer laser conditions. Each form of carbon produces a different signature.

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New magnetic polymers may advance spintronics technologies

Researchers at the U.S. Department of Energy's Argonne National Laboratory have pioneered a new approach for making magnetic polymers that are held together with very strong hydrogen bonds. These polymers contain an innovative bifluoride, HF2–, building block that allows a magnetically ordered state to be obtained. The development may help lead to new techniques for faster and more versatile computer chips, among other applications.

The research is reported in the December 21 issue of Chemical Communications and is featured on the cover of the journal.

The research examines the role of hydrogen bonds in designing the structure of molecular materials. “Nature uses hydrogen bonds to do all kinds of things, including holding the DNA double helix together, and is important in a wide range of biological processes,” said John Schlueter, Argonne chemist and an author of the research paper. “When making molecular materials, strong bonds are needed to fabricate the molecular building blocks. Weaker bonds, including hydrogen bonds, act as the glue to hold the blocks together.” It's this phenomenon that allowed the creation of the first fully organic superconductor, discovered at Argonne a decade ago.

The magnetic polymer, which forms as beautiful deep blue crystals, is produced when copper ions bind to pyrazine molecules, creating a sheet-like structure. Like a Tinkertoy® building block, the bifluoride ion acts as a bridge to hold the planes together. The product is a three-dimensional coordination polymer, which forms through very mild synthetic conditions.

The exceptionally simple structure is held together by one of the strongest hydrogen bonds known, making this a very thermally stable material. Each copper ion, which sits at the corner of a molecular cube, contains one unpaired electron. These spins are disordered at normal temperatures, a state known as paramagnetism; however, the spins begin to align in opposite directions as the temperature drops, creating a magnetic state called antiferromagnetism.

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Ruling Upholds Eli Lilly’s Patent on Drug

By BLOOMBERG NEWS
Eli Lilly & Company won a federal appeals court ruling on Tuesday upholding its patent on Zyprexa, the world’s top-selling schizophrenia drug.

The United States Court of Appeals for the Federal Circuit, in Washington, affirmed a lower court decision that the patent was valid. The Ivax unit of Teva Pharmaceutical Industries and Dr. Reddy’s Laboratories had claimed a federal judge was mistaken in ruling the drug was protected until Lilly’s patent expires in 2011.

In addition, “Lilly did not fail to disclose information” to the patent office, as its rivals suggested, the judges said in their 21-page opinion. The opinion upheld a decision by Judge Richard L. Young of United States District Court in Indianapolis.

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FDA May Clear Cloned Food, But Public Has Little Appetite

Despite Safety Data, Americans Largely Find Idea Unappealing

By Rick Weiss
Washington Post Staff Writer
Monday, December 25, 2006; Page A16

Consumer advocates and others have complained bitterly in recent years that the Food and Drug Administration has veered from its scientific roots, making decisions on controversial matters -- such as the emergency contraceptive "Plan B" -- on political rather than scientific grounds.

Now comes a test of just how rational the public wants the FDA to be.

Later this week, the agency is expected to release a formal recommendation that milk and meat from cloned animals should be allowed on grocery store shelves. The long-awaited decision comes as polling data to be released this week show that the public continues to have little appetite for such food, with many people saying the FDA should keep it off the market.

The FDA decision is based on a substantial cache of data from rigorous studies, all of which have concluded that milk and meat from cloned animals is virtually identical to such products from conventional animals. Scientists have also been unable to detect health problems in laboratory animals raised on clonal food.

By contrast, studies have found that consumers' discomfort with the idea of eating food from clones is largely based on vague emotions. Indeed, polls have repeatedly found that the public understands little about what cloning really is.

That raises the issue: Should decisions such as this one be based solely on science, or should officials take into account public sensitivities, which may be unscientific but are undeniably real?

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Public misinformed about stem cell issue

By TIMBERLY ROSS, Associated Press Writer
Mon Dec 18, 9:34 PM ET

OMAHA, Neb. - Research on embryonic stem cells continues to ignite national debate over the beginning of human life. And with the Legislature likely to take up the issue in its next session, many worry that inaccurate information is being perpetuated by stem cell proponents and their counterparts.

Dr. David Crouse, who oversees some stem cell research at the University of Nebraska Medical Center, said both sides are "overselling wares."

The sentiment is shared by Chip Maxwell, executive director of the Nebraska Coalition for Ethical Research. That group supports stem cell research, but not the kind involving embryos.

Maxwell said he is all for the free flow of ideas but that information should have balance. "I hope that the whole picture is explained," he said.

From a scientific standpoint, stem cells are building blocks that can turn into different types of tissue, such as kidney or liver cells. Research is being conducted on two types of stem cells — adult and embryonic — in hopes that they can lead to cures for diseases.

Adult stem cells can be found in bone marrow and umbilical cord blood, among other sources. Embryonic stem cells are derived from human embryos in their earliest stages of development.

Embryonic stem cells in particular have made headlines, as scientists attempt to harness them to regenerate damaged organs or other body parts. They're essentially a blank slate, able to turn into any tissue given the right biochemical instructions.

But from an anti-abortion standpoint, human embryonic stem cell research is immoral, because isolating the cells destroys embryos, what some believe is the starting point of human life. Anti-abortion advocates cite the same argument in opposing abortion.

"The beef is that there is no question that embryos are destroyed in the harvesting of stem cells," Maxwell said. "Now you are destroying a human being."

Many scientists disagree. Crouse, who specializes in embryonic stem cells, said it boils down to a difference in perspective about when human life begins.

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Scientists get OK for engineered peanuts

By ELLIOTT MINOR, Associated Press Writer
Tue Dec 26, 7:40 PM ET

ALBANY, Ga. - A leading industry group has given scientists the go-ahead to build genetically engineered peanuts that could be safer, more nutritious and easier to grow than their conventional version.

The work could lead to peanuts that yield more oil for biofuel production, need less rainfall and grow more efficiently, with built-in herbicide and pest resistance — traits that have already been engineered into major crops such as cotton, corn, soybeans and canola.

For consumers, the work could lead to peanuts with enhanced flavor, more vitamins and nutrients, and possibly even nuts that are less likely to trigger allergic reactions, a life-threatening problem for a small percentage of the population and a major food industry concern.

A few researchers have been genetically modifying peanuts for at least a decade, but their discoveries have had little impact because the industry, fearing a consumer backlash, was reluctant to support the work.

However, with the two leading peanut-producing countries, China and India, working aggressively on transgenic peanuts, the American Peanut Council and its research arm, the Peanut Foundation, this month approved a major policy change. The council represents all segments of the industry — growers, shellers, exporters and manufacturers.

The foundation urged scientists to move ahead with "due diligence" on genetically engineered peanuts.

The work is expected to cost about $9.5 million and will require university, government and industry support.

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Couple gives $25 million to Marquette

Anonymous donors hope to help transform engineering school
By JESSE GARZA
jgarza@journalsentinel.com
Posted: Dec. 18, 2006

A Marquette University engineering alumnus and his wife have pledged $25 million to Marquette's College of Engineering, a donation that could lead to future donations from the couple of $1 million a year, university officials announced Monday.

The commitment to the annual funding would be part of a "legacy grant" to the college, said Julie Tolan, vice president of university advancement for Marquette.

The funding would last "literally forever" and would be unprecedented in the history of the university, Tolan said.

"It certainly would be an unusual scenario in philanthropic initiatives if it existed (anywhere) before," Tolan said.

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Mouse study reveals stem cell capability in brain tissue repair

UCSF scientists have determined that adult stem cells in a specific region of the mouse brain have a built-in mechanism that allows the cells to participate in the repair and remodeling of damaged tissue in the region.

As the cells are also present in the human brain, the same capacity or potential may exist in humans, the researchers say. If they do, it is possible that the cells’ behavior could be enhanced to treat tissues damaged throughout the brain by disorders such as stroke and traumatic injury.

The study, reported in the December 15 issue of Cell, was led by Chay T. Kuo, MD, PhD, a UCSF postdoctoral fellow in the laboratory of senior investigator Yuh-Nung Jan, PhD.

Kuo is one of 16 UCSF CIRM Stem Cell Scholars – up and coming young scientists funded by the California Institute for Regeneration Medicine, established by California voters in 2004 to allocate $3 billion over 10 years to support stem cell research.

“The results were very surprising,” says Kuo. “Our results show that neural stem cells in mice have the ability to sense damage in their environment that leads to their subsequent proliferation to help restore local tissue integrity. If we can figure out how this happens, and determine that it occurs in human neural stem cells, we may be able to increase the effect and harness it for therapeutic use.”

Understanding this proliferative capacity during environmental change is critical, he says, as adult neural stem cells in this region may sometimes proliferate out of control to form brain tumors. This possibility has been reported and is being explored by scientists in the UCSF Institute for Regeneration Medicine and UCSF Department of Neurological Surgery.

The scientists focused their study on postnatal neural stem cells that lie next to the lining of the brain’s lateral ventricles, or cavity, in a region known as the subventricular zone (SVZ). In 1999, the lab of study co-author Arturo Alvarez-Buylla, PhD, UCSF Heather and Melanie Muss Professor of Neurological Surgery, discovered that cells in this region known as astrocytes function as adult neural stem cells in mice (Cell, June 11, 1999) and later discovered similar cells within the human brain (Nature, Feb. 19, 2004). The cells are recognized as a major source of adult stem cells in the mammalian brain.

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Very high frequency radiation makes dark matter visible

The stars and gas which are seen in galaxies account for only a few percent of the gravitating material in the Universe. Most of the rest has remained stubbornly invisible and is now thought to be made of a new form of matter never yet seen on Earth. Researchers at the Max Planck Institute for Astrophysics have discovered, however, that a sufficiently big radio telescope could make a picture of everything that gravitates, rivalling the images made by optical telescopes of everything that shines (online: 28. November 2006).

As light travels to us from distant objects its path is bent slightly by the gravitational effects of the things it passes. This effect was first observed in 1919 for the light of distant stars passing close to the surface of the Sun, proving Einstein's theory of gravity to be a better description of reality than Newton's. The bending causes a detectable distortion of the images of distant galaxies analogous to the distortion of a distant scene viewed through a poor window-pane or reflected in a rippled lake. The strength of the distortion can be used to measure the strength of the gravity of the foreground objects and hence their mass. If distortion measurements are available for a sufficiently large number of distant galaxies, these can be combined to make a map of the entire foreground mass.

This technique has already produced precise measurements of the typical mass associated with foreground galaxies, as well as mass maps for a number of individual galaxy clusters. It nevertheless suffers from some fundamental limitations. Even a big telescope in space can only see a limited number of background galaxies, a maximum of about 100,000 in each patch of sky the size of the Full Moon. Measurements of about 200 galaxies must be averaged together to detect the gravitational distortion signal, so the smallest area for which the mass can be imaged is about 0.2% that of the Full Moon. The resulting images are unacceptably blurred and are too grainy for many purposes. For example, only the very largest lumps of matter (the biggest clusters of galaxies) can be spotted in such maps with any confidence. A second problem is that many of the distant galaxies whose distortion is measured lie in front of many of the mass lumps which one would like to map, and so are unaffected by their gravity. To make a sharp image of the mass in a given direction requires more distant sources and requires many more of them. MPA scientists Ben Metcalf and Simon White have shown that radio emission coming to us from the epoch before the galaxies had formed can provide such sources.

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