Developments to Watch
Tuberculosis: Developing a Breath Test
Take a whiff of this: Professor Joseph Stetter and researcher Bill Penrose from the Illinois Institute of Technology in Chicago have developed several prototypes of an electronic nose that could let doctors sniff out tuberculosis by its odor. One prototype is a cylinder about the size of a thimble with electronic sensors inside. Another is a vibrating crystal--it looks like a transparent dime--that absorbs bacteria from the air. Soon, the researchers intend to plant one of these tiny wonders in a tuberculosis-detecting breathalyzer: a small bag with a tube that you blow into.
The challenge is to make the artificial schnozz more sensitive. One way to do that, researchers say, is to take large, one-gallon breath samples and condense them into the cylinder, thus boosting sensitivity up to one-thousandfold.
The benefits of the "e-nose" could be huge: Penrose says it could slash diagnosis time from as much as six weeks now down to just 10 minutes. "You save the cost of keeping people confined to the hospital," he says, and get them quickly onto healing drugs.By Roger O. Crockett; Edited by Neil GrossReturn to top
Mirror Magic for Optical Networks
The optical networking revolution continues its march. The latest advance in photon-based technology comes from startup Xros Inc. in Sunnyvale, Calif. On Mar. 6, it will unveil an all-optical device known as a cross-connect switch, which is essentially a network box that switches communications circuits between two different destinations.
On today's fiber-optic networks, pulses of light are widely used to carry voice and data across long distances. But when these optical pulses must be transferred, or "switched," from one hub of the network to another, the pulses must first be converted to electrical signals and then turned back into light pulses. Xros eliminates this step by using thousands of densely packed micromirrors to bounce light beams through the switch.
Lucent Technologies Inc. and Corvis Corp. are developing similar switches. But neither has the capacity and density of Xros' system, which aims to connect up to 1,152 pairs of mirrors the size of a pinky nail. "They have the lead in the all-optical switch area," says Max Schuetz, an analyst at Thomas Weisel Partners. The devices will be tested with three customers this August. And AT&T and MCI WorldCom Inc. may use the new switches on their main Internet trunk lines.By Spencer E. Ante; Edited by Neil GrossReturn to top
Diamonds Are a Tiny Machine's Best Friend
Tiny machines called mems--or microelectromechanical systems--are built with parts no bigger than grains of pollen. Typically made from silicon, these futuristic devices are already driving computer-game joysticks and miniature satellite mirrors. But just like other machines, MEMs wear down over time. And that limits their usefulness in electronic gadgets and newfangled medical devices.
Now, a new technology developed at Sandia National Laboratories seeks to extend the life expectancy of many types of MEMS. Two scientists, John P. Sullivan and Tom Friedmann, have developed and patented a process to build micromachines from amorphous diamond--the hardest material in the world after crystalline diamond.
Micromachines fabricated from diamond are superior to silicon versions in several ways. First, they're extremely durable. Amorphous diamond is thought to be 10,000 times as wear-resistant as silicon. Second, diamond films are biologically inert. That means they could be used as long-acting drug-delivery devices with no danger of triggering an immune reaction.
In their first attempt, Sullivan and Friedmann built a motor barely the width of a human hair from two teeny diamond combs (picture). When an electrical current is run through the device, the combs' teeth attract and repel each other, and create enough energy to drive a tiny diamond shuttle back and forth.By Ellen Licking; Edited by Neil GrossReturn to top