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Silicon Gets a Reprieve--by Way Less Than a Hair


Once again, silicon experts have prolonged the usefulness of the world's premier semiconductor material. The business of engraving ever-finer circuits in silicon was supposed to hit a wall around 2015, forcing the chip industry to switch to some exotic new concept, such as quantum physics--and chuck a half-century of accumulated know-how. That deadline has now been postponed, perhaps indefinitely, judging from several research papers at this year's International Electron Devices Meeting, which ended in San Francisco on Dec. 11.

The IEDM is a showcase for semiconductor breakthroughs with long-term implications, and two papers were especially upbeat. One dealt with the challenges of insulation. Engineers have long assumed that when circuit lines shrink to less than 10 nanometers wide, or 100,000 times thinner than a human hair, existing methods of insulating wires and transistors would prove too flimsy, leading to catastrophic short circuits. But researchers at Agere Systems (the former chipmaking arm of Lucent Technologies) recently discovered that the properties of the silicon-dioxide insulation used today actually change for the better as dimensions shrink into the nanoscale realm. So, no matter how fine these lines become, effective insulation could be available.

As if to prove the point, IBM scientists reported that they have made a working transistor only 6-nm wide. That's one-third smaller than the size projected to enter production in 2016. The company also found that ultrathin insulation seems feasible. Get ready for chips crammed with a billion transistors or more. Nanotechnologists believe that proteins and other complex molecules might make excellent micromachines--more versatile than anything an engineer could build from scratch. But how do you customize the specific molecule, or tell it what to do?

Scientists at Massachusetts Institute of Technology are tackling these issues by fitting molecules with tiny antennas, then sending simple instructions via radio. As described at a recent Materials Research Society meeting in Boston, MIT Associate Professor Joseph Jacobson and his team attached gold nanoparticles to DNA molecules in a solution inside a plastic tube. When exposed to an oscillating magnetic field, the gold-tagged DNA unwound, then wound back up when the power was shut off. Ultimately, this technique could let doctors switch off harmful genes in a cell or activate good ones. And cell-size machines could be crafted by radioing instructions to enzymes, directing them to cut and paste pieces of proteins. When a tornado swoops down on a community, residents have precious little time to get out of harm's way--generally no more than 11 minutes. To double that warning time and help save lives in the Midwest's tornado alley, a consortium led by the U.S. Navy and the National Weather Service is devising a tornado-detection system using fancy radar from Lockheed Martin.

Current systems rely on Doppler radar with a dish antenna that rotates to scan the surrounding terrain. Only when it is pointing in the right direction can the antenna spot an approaching funnel or the atmospheric changes that often precede a storm. But Lockheed's phased-array radar, developed for Navy ships, has an antenna that can be electronically steered to look instantly in any direction--and lock onto ominous signs to speed computer analysis. "It can scan a whole area much faster," says Scott A. Sandgathe, a meteorologist at the University of Washington in Seattle. Tests are slated for April at a $25 million facility being built in Norman, Okla., funded mainly by the Office of Naval Research. -- Boston researchers have discovered that zebrafish can regenerate damaged heart muscle--a finding that could pave the way for regeneration of injured heart tissue in people. In the Dec. 13 issue of Science, a team led by Dr. Mark T. Keating of the Howard Hughes Medical Institute at Children's Hospital reports that it surgically removed 20% of the muscle from the lower ventricle of zebrafish and then returned them to water. Within a week, the fish were swimming normally, and within two months their hearts had regained their original size and shape. Recognizing that the zebrafish genome shares many characteristics with that of humans, the scientists will now investigate which genes are responsible for the felicitous regrowth.

-- Europe is thinking big about a new telescope--really big. Its mirror would be 100 meters (330 feet) in diameter, dwarfing the current champs, the twin 10-meter telescopes at the W.M. Keck Observatory on the summit of Hawaii's Mauna Kea volcano. With a mirror as big as a football field, astronomers might see earth-size planets circling nearby suns instead of just inferring their presence on the basis of gravitational distortions. Scientists working on the monster telescope have asked the European Union for funding.


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