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A Teensy-Weensy Welder for Nano Workers


Nanotubes offer an ever expanding list of promising uses, from ultrafast chips to superstrong materials. But the tools are still evolving to arrange these cylinders--with walls just one carbon atom thick--into building blocks for useful structures. Now, a molecular-scale welding method is taking scientists one step closer to harnessing nanotubes.

A team led by Pulickel Ajayan, a professor at Rensselaer Polytechnic Institute in Troy, N.Y., uses a high-voltage electron microscope to heat the area where two single-walled nanotubes overlap. The process creates bonds with similar strength and electrical properties to the surrounding nanotubes. "We can begin to control the arrangement and conductivity of the carbon strands," Ajayan says. Next, he wants to see if cheaper ion beam guns used in microelectronics manufacturing can accomplish the same task. China is planning an unusual celebration to end the year. On Dec. 31, a group of Beijing officials will join local dignitaries in Shanghai for rides on China's new magnetic-levitation train. It will literally fly the 19 miles between downtown Shanghai and Pudong Airport at a blazing 270 mph, suspended less than one-half inch in the air on magnetic-force fields. When the system enters full-time service next June, it will become the world's only commercial maglev train.

Others may soon follow. Transrapid International, the Berlin company supplying the maglev technology, predicts that the Chinese achievement will breathe new life--and funding--into several maglev projects in Europe and the U.S., some of which have been studied for a decade or more. Next year, Congress is set to take another look at maglev trains for the U.S. when it considers a new transportation appropriations bill, and J. Christopher Brady, president of Transrapid International USA, boasts that maglev offers tempting economics. If members of Congress were to pump new money into Amtrak, Brady says, "they'd probably have to subsidize it every year afterwards. But if they commit the same capital infusion to maglev, they'll never see us again."

Because maglev eliminates the friction between wheels and rails, he explains, both maintenance and operating expenses are slashed by 33% or more--enough to make most train service profitable. That's one reason China is now studying a maglev line running from Shanghai to Beijing, 800 miles north. For 25 years, Dr. Steven A. Rosenberg, chief of surgery at the National Cancer Institute, has been trying to prod the immune system into seeking out and killing cancer cells. Early on, he discovered that the body does manufacture killer T-cells aimed at tumors, but the response is far too feeble to beat back the cancer. So Rosenberg tried extracting such killer cells from tumors, growing them in large numbers, and putting them back into the body. Unfortunately, the cells typically last for only a few hours, not long enough to make a difference.

Now, Rosenberg has developed a more radical--and promising--approach. Before adding back billions of the tumor-fighting cells, he uses drugs to temporarily eliminate the body's normal immune system. The reinfused killer T-cells then divide and spread like wildfire in the body, creating a powerful army against the tumor. "This is a technique for generating staggering amounts of tumor-fighting cells," he says.

In the first results, described Sept. 19 in the online edition of Science, 6 of 13 patients with advanced metastatic melanoma had dramatic or noticeable tumor regression. One patient, 16 years old at the time of treatment, is cancer-free two years later. Rosenberg's lab is now trying to figure out why three of the patients had no response--and is working on ways to boost T-cells further. -- Research by the National Institutes on Aging has found evidence that common pain relievers may delay the onset of Alzheimer's disease. The study, reported in the journal Neurology, discovered that the long-term use of aspirin and nonsteroidal anti-inflammatory drugs (NSAIDS), such as ibuprofen, may reduce the risk of the disease, provided they are used well before the onset of dementia. Investigators assessed 5,092 residents aged 65 and up of Cache County, Utah, for signs of Alzheimer's, and took their drug histories. When participants were reexamined three years later, the researchers found that the risk of developing Alzheimer's for those who had taken NSAIDS regularly more than two years before the start of the trial was 45% less than for nonusers.

-- An epilepsy drug may help prevent migraines, says new research. And it has potentially welcome side effect--weight loss. Dr. Stephen Silberstein of Thomas Jefferson University in Philadelphia told a recent migraine meeting that the Johnson & Johnson (JNJ) drug Topamax quieted over-excited brain cells, which sensitize pain centers. In a study of 400 patients, about half of those given Topamax saw the number and length of their headaches halved. The patients also lost an average of 3.8% of their body weight.


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