The Cutting Edge: COMPUTING / TECHNOLOGY / INNOVATION : Learning to Walk, Byte by Byte
When the spinal cord is severed in an accident, it’s like a telephone that has been unplugged: The electrical signals from the brain and the muscles in the legs are disconnected, resulting in paralysis.
But more than 300 patients with spinal-cord injuries across the country have learned to walk again with the Parastep System developed at the University of Illinois at Chicago. Using a walker for balance, people paralyzed from the waist down can stand up from a sitting position and walk short distances. While Parastep’s inventor, professor of electrical engineering and computer science Daniel Graupe, says that the system is not a cure, people trained to use the system can now stand up, reach into a cupboard and talk to people at eye level.
The portable electronic device, which has won approval from the Food and Drug Administration after 13 years of clinical testing, is built around a microcomputer that sends electrical pulses to a patient’s legs, causing the muscles to contract. The signals are controlled by the user’s upper body movements, fingertip controls on the walker, or voice commands and sent to electrodes attached to various points on the legs.
About the size of a personal stereo, the microcomputer runs on eight AA batteries and is worn around the waist. Patients must go through 32 hours of physical therapy to learn how to use the system on their own. Parastep is being manufactured and marketed by Sigmedics Inc., in Northfield, Ill.
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Banning Background Noise: Hands-free cellular technology means drivers devoted to talking and driving can keep their hands on the wheel while they schedule breakfast meetings or trade stocks. The problem is that in confined areas like the passenger section of a car--or in large areas like an office conference room where hands-free speakerphones are also used--there is an unwanted echo that often makes it difficult to understand someone talking over the speakerphone.
That echo is the reverberation of the speaker’s voice at the other end of the line as it is fed back through the speaker inside the car or conference room. Now, researchers at Texas Instruments’ Integrated Systems Laboratory, Semiconductor Group, have come up with a way to ban that background noise with an echo cancellation algorithm.
For the cellular telephone speaker, a digital signal processing (DSP) algorithm was developed that accommodates the reverberation generated in the short distance the voice travels from the loud speaker to the surrounding car walls. Using this algorithm, the speakerphone will be able to generate a replica of the echo and thus cancel the echo from the initial signal.
Inside an automobile, many of the lower frequencies are drowned out by road noise, so the algorithm focuses on the higher frequencies. Because the echo takes longer to occur in larger rooms and the quality of the voice should be better than in a car, this filtering system will be more complex than the car system.
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Faster Pharmaceutical Research: While the pharmaceutical industry’s R&D; expenditures grew at a compound annual rate of about 12% between 1988 and 1992, the number of new chemical entities introduced in 1991 was approximately half that in 1986. To speed up research, reduce costs and bring pharmaceuticals to market faster, the industry has turned to a drug research methodology called combinatorial chemistry.
This approach uses a mix of technologies that allow researchers to simultaneously create and investigate a wide range of materials. Used in conjunction with high throughput screening (HTS), a method of using robotics and other automation equipment to rapidly test compounds for their biological activity, combinatorial chemistry promises to speed research in AIDS drugs and other important areas.
A San Leandro, Calif.-based company, MDL Information Systems Inc., recently released the first software exclusively designed for combinatorial drug research. Using MDL’s Project Library, researchers can easily build and manipulate vast libraries of chemical data which describes the structure and behavior of millions of molecules and molecular fragments.
Controlling this data is key to tracking the results of massive combinatorial experiments: identifying structures of active compounds, managing work flow and monitoring costs. The library was developed by studying the technical and scientific requirements of 50 pharmaceutical, biotechnology and agrochemical companies. Merck & Co. is among the first companies to purchase Project Library, which runs on Windows platforms with 486 or Pentium processors.
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Out Damned Clot: Balloon angioplasty, the technique that reopens a clogged artery by inflating a small “balloon” inside it, has a 40% failure rate. That’s because angioplasty forcibly expands the artery, often damaging the arterial lining and causing a blood clot to form on the blood vessel’s wall, again constricting the artery.
Jeff Hubbell, a professor of chemical engineering at Caltech, is collaborating with an Arizona cardiologist to develop a biodegradable polymer gel that would lower the failure rate by promoting better healing of the artery. In experiments, he has successful coated the lining of an artery with a gel that prevents the formation of clots immediately following angioplasty. The gel then degrades within a day, leaving the artery clear so blood can flow freely.
