Developments to Watch
GILDING THE ULTIMATE CHIP
THE GOLD NUGGETS BEING EXTRACTED BY these Purdue University researchers (picture) are far too tiny to be seen by the naked eye. But they could be pay dirt for chipmakers in the future. Each contains only about 500 atoms of gold. It would take a string of 250,000 of these nanonuggets to span the head of a pin.
The nuggets are so small that an electrical current can exist only in the form of a single electron passed off from one nugget to the next. For the chip industry, single-electron signal flows are the ultimate dream: Nothing could be smaller. "We're working hard on ways of making logic and memory circuits," says team member Ronald P. Andres, a professor of chemical engineering at Purdue.
He's confident of eventual success because the technology--and the challenges ahead--are fairly straightforward. The nuggets are precipitated from gaseous gold and wrapped in organic molecules, then dissolved in a solvent. The mixture is painted on a silicon wafer. The solvent evaporates, and the nanoclusters form an ultrathin conducting film.
The Purdue University researchers' next goal is to control the self-assembly process to produce circuit lines instead of a film. The research has already sparked interest from chipmakers, especially in Japan, says Andres. "But we've got a lot of work to do before we can make millions of chips."EDITED BY NEIL GROSS By Otis PortReturn to top
EARLY-WARNING BUGS FOR TRANSFORMERS
ELECTRICAL-UTILITY TRANS-formers have a habit of failing unpredictably, sometimes causing explosions, fires, and contamination. Oil is used as an insulating barrier between the transformer's high-voltage and lower-voltage wire windings. But moisture and explosive gases eventually build up in the oil, forming a pathway for a sudden, dangerous electric arc between the windings. Spot checks don't help, because the oil can be fine for years, only to deteriorate in a matter of days.
Larson-Davis Inc. of Provo, Utah, says it has a solution to the problem: a package of sensors including one called CrossCheck developed by scientists at the company and Brigham Young University. A CrossCheck sensor spots when the oil begins to lose its effectiveness as an insulator by detecting a change in an extremely low frequency electrical signal that's sent through the oil. The early-warning package, placed permanently inside the transformer, also includes a gas sensor and a vibration sensor derived from the company's work on submarine-chasing detectors. The vibration sensor predicts mechanical failure from the change in the transformer's hum. The package's cost: $5,000 to $25,000 per transformer.EDITED BY NEIL GROSS By Peter CoyReturn to top
NEW HEMOGLOBIN FROM OLD BLOOD
SCIENTISTS HAVE BEEN struggling for decades to develop an inexpensive and safe replacement for hemoglobin--the oxygen-carrying component in red blood cells. Such a substitute, in theory, would be ideal for emergency rooms, where donated blood is always in short supply. Analysts figure a blood substitute could be worth $2.5 billion annually. But the human body doesn't tolerate such tampering easily. A half-dozen biotech and medical-equipment companies have products wending through Food & Drug Administration trials, but there are still no products on the market.
Progress comes in small steps. In June, Baxter International Inc. in Deerfield, Ill., received FDA approval to move its HemAssist product into Phase III clinical trials--a large, double-blind test for efficacy in surgery patients. Baxter could receive special FDA clearance for trauma patients within months. The company's patented process, shown to be safe in earlier trials, involves retrieving millions of hemoglobin molecules from red cells in outdated donated blood. These are purified to eliminate the danger of transmitting diseases. Baxter cross-links the molecules to stabilize them (illustration) and prevent rapid excretion from the kidneys. After that, they are safe to inject into the patient's bloodstream.EDITED BY NEIL GROSS By Ron Stodghill IIReturn to top