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IN DEVELOPMENT / KATHLEEN WIEGNER

The Cutting Edge: COMPUTING / TECHNOLOGY / INNOVATION : Getting to the Heart of Palpitation Control

March 22, 1995|KATHLEEN WIEGNER

A team of researchers from Emory University and Georgia Institute of Technology's Applied Chaos Laboratory expects to begin human testing this spring of a technique that may help control irregular cardiac rhythms by altering chaotic patterns in the electrical signals controlling the heart.

If successful, the technique could lead to development of a new type of implantable device that would be smaller and apply less electrical energy than the defibrillators now used to correct an erratic heartbeat.

Also called atrial fibrillation, the malady is the most common heart irregularity requiring treatment. It affects about 5% of all individuals over 60 years of age. The disorder may cause palpitation, shortness of breath and weakness, and may predispose those affected to blood clots and stroke. Medications are only partially effective and are associated with frequent and sometimes dangerous side effects.

Existing defibrillators use large electrical shocks to overwhelm harmful cardiac rhythms and return the heart to a normal pattern. The technique used by the researchers would apply small electrical signals to the heart at carefully chosen points in the heartbeat cycle. These small signals would encourage the heart itself to correct the irregularities. The research has been sponsored by the U.S. Office of Naval Research; a pacemaker company, Medtronic, and Georgia Institute of Technology. Patented techniques for cardiac control have been licensed to Medtronic and Control Dynamics, a company formed by Georgia Tech physicist William Ditto and others to exploit and commercialize chaos control and anti-chaos control techniques in biology, medicine, electronics and engineering.

Laser Scissors: The textile industry may soon get a new cutting tool that could slash costs as well as fabric, if all goes well for its inventor and his team at Los Alamos National Laboratory.

The scientists' tool is based on a type of gas-powered laser called an excimer laser, combined with a series of lenses and a holographic filter that focus the laser light to slice through the fabric.

The system works much in the same way that a photographic enlarger exposes an image by allowing light to pass through a negative onto light-sensitive paper. The laser exposes the fabric to intense ultraviolet light through a holographic-patterned filter to cut the material in the desired shape. An entire pattern can be cut in less than one second.

The development of the laser scissors is part of a $25-million cooperative research and development agreement between representatives from the 26,000 companies making up the textile industry and the ten national laboratories. Los Alamos scientist Martin Piltch recently received a patent for the laser scissors.

Eyes as Computers: More often than perhaps we would like, nature outperforms our best technology. The brain processes information better than any computer; no robot has yet achieved the dexterity of the human hand. Now scientists at the National Institute of Standards and Technology are studying whether one of the proteins in the human eye could be used for storing digital information.

The eye is tremendously efficient when it comes to rapidly processing vast amounts of information. Proteins in the eye respond instantaneously to light of various colors and intensities.

One of these proteins, rhodopsin, which is found in bacteria as well as animal and human eyes, will switch from one form to another under different-colored lights. Since each rhodopsin molecule responds independently, each one could serve as an on-off switch for storing computer information.

Michail Ostrovsky, a guest researcher from the Russian Academy of Sciences, recently found a way to stabilize octopus rhodopsin so that it could be reused indefinitely. Other NIST researchers are working on ways to modify rhodopsin from bacteria to respond to infrared light. And in a cooperative research and development agreement with the University of Wisconsin, researchers are making and characterizing single-layer rhodopsin films.

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