Technology Bulletin6-8-98
June 8, 1998
June 8, 1998 Design News
Technology bulletin
Late developments that shape engineering
by Gary Chamberlain, Senior Editor
Heel-density measurement detects osteoporosis...
Osteoporosis afflicts an estimated 10 million Americans, mostly elderly women. Some 189 million others have low bone mass. All are at risk for severe injury, such as breaking a hip, as well as chronic pain and stooped posture as bones in the spine and other areas fracture. However, tests for detecting this crippling disease earlier are getting easier and less expensive, thanks to a system developed by Hologic Inc. (Waltham, MA). Called Sahara, the system is said to be the first osteoporosis test that does not use x-rays. Instead, the device relies on ultrasound to assess a woman's bones by measuring the density of her heel. Slip the foot into a small box about the size of a laser printer and the sound waves painlessly penetrate for a mere 10 secs. Bone density is determined by how easily and quickly the sound waves move. The system automatically analyzes the results, and, a minute later, spits out a slip of paper with the bone measurement. The Sahara costs $30,000, and Hologic estimates that patients will pay about $40 for the test. In contrast, today's osteoporosis tests are performed by large, specialized x-ray machines that typically measure a patient's hip or spine. They cost $70,000 to $150,000, and patients are charged $127 for the leading x-ray test, according to Eric von Stetten, Hologic's director of ultrasound technologies. FAX (781) 890-8031.
...while study shows you can 'just say NO' to bone loss
When Mae West pronounced that too much of a good thing sometimes is a good thing, she probably didn't have the versatile molecule nitric oxide (NO) in mind. However, biologists at Washington University (St. Louis) have shown that a high concentration of NO in osteoclast bone cells might keep them from eating away too much bone, preventing bone loss associated with such diseases as osteoporosis. A team led by Philip Osdoby, a professor of biology, introduced an antibody into the osteoclasts that halted bone resorption, a process where bone is gnawed away by osteoclasts that are too numerous or too active. Biochemical tests showed that, after adding the antibody, an increase in NO occurred, followed by decreases in bone resorption. Osdoby believes that NO acts as a signal to turn the osteoclast off. "With a better understanding of how NO is regulated in osteoclasts, we may be able to develop new strategies to prevent bone loss," Osdoby adds. E-mail [email protected]
Headless robot provides insights into how humans walk
It doesn't have a brain or a heart, and its walk is a little like the scarecrow's. But a little, headless, armless, trunkless, two-legged robot developed at Cornell University can walk, wobble, hobble, limp, stride, and stagger--even though it can't stand still without falling over. Made of plastic Tinkertoy parts and a few odds and ends, the robot remains stable while in motion, giving mechanical engineers new insights about how humans walk. Michael J. Coleman, a lecturer in mechanical engineering at Cornell, says the little worker, by using gravity on a gentle slope, "performs repeatable, chattering, human-like steps without falling over." Coleman stumbled on the walker's design while preparing for his doctoral defense. "It is one of the few devices of any kind that is dynamically stable near a statically unstable configuration and doesn't have fast spinning parts," says Andy Ruina, director of the Human Power, Biomechanics and Robotics Laboratory at Cornell, who assisted Coleman. The Tinkertoy device consists of two green rod legs bottomed with rounded yellow feet into a red crossbar hip, along with several orange washers and green hinges. To stabilize the toy, Ruina added low-lying red and yellow outriggers weighted with steel nuts off each foot to lower the centers of mass. He further fine-tuned the toy by rounding out the flat spots of the Tinkertoy wheels with flexible brass strips. Soon, the hand-sized gadget was tottering down a gentle slope, tilting from side to side, but steadily walking on and on and on. E-mail [email protected]
Petri test uncovers potentially deadly E. coli bacteria
Strains of E. coli and salmonella kill about 1,250 Americans and infect more than 2 million others each year. As a result, government researchers have expanded their testing program for slaughter houses, with the focus on methods to speed tests for the deadly bacteria. They may not have to look beyond a new testing device developed at Springfield (MA) College. Most existing food tests yield initial results in two to three days, sometimes letting bad meat reach consumers, threaten health, and force recalls. The Springfield College test, according to inventors Chun-Kwun Wun, a microbiologist, and Frank J. Torre, a chemist, can check for E. coli and salmonella within 8 to 24 hrs. The core of the test, performed in a specially designed petri dish, contains chemicals that encourage the bacteria to migrate toward a serum containing antibodies for the strain of microbe under test. When bacteria and antiserum collide, they clump together to form a visible, cream-colored line--the indicator of a positive result. The inventors say the test will cost considerably less than most others and be easier to use. "We can actually grab anybody from the street and train them within two to three hours to do the test," says Wun. The college hopes to license the patented test so that it will reach the market possibly by the end of the year. Phone (413) 748-3044
'Movies' of heart's signals may lead to new life-saving devices
Ventricular fibrillation kills thousands of Americans each week by inducing abnormal electrical signals that turn their hearts into quivering "bags of worms" no longer able to pump blood. Victims die within minutes, unless the erratic heart rhythms can be halted with massive jolts of electricity from a defibrillator. Medical researchers have moved one step closer to understanding the causes of ventricular fibrillation through a series of high-resolution movies that show how the condition disrupts the electrical signals that normally govern the heart. The high-speed imaging system produced for the research also revealed that ventricular fibrillation may develop in two distinct phases. The movies pinpointed a series of unusual spiral waves that originate with "rotors" near the surface of the heart. The waves rapidly expand, flow across the heart muscle, merge, and even interfere with each other, causing heart cells to contract in an uncoordinated way. The imaging system used by the research team produces detailed information from as many as 16,000 points on a portion of the exterior surface of the heart. Operating at 838 frames per sec, it allowed the team, consisting of researchers and physicists from the U.S. and Canada, to capture the rapid and disorganized waveforms for analysis. The system relies on fluorescent dyes that respond to electrical changes in the cells of the heart muscle. The researchers expose the beating heart to high-intensity lights, then image and intensify specific wavelengths of light returned by the dyes. Knowing how these unique waves form and behave could provide the information needed to design and test control techniques that may provide an alternative to existing defibrillators--which deliver the electrical equivalent of "a bowling ball dropped onto your chest from a two-story building," according to William L. Ditto, professor of physics at the Georgia Institute of Technology, one of the study's co-authors. E-mail [email protected]
Microscopic materials may lead to new medical devices, cures
Particles so small that only the newest and most sensitive instruments can see and study them are being used to create new materials and devices that could revolutionize everything from drug delivery to sunscreens. That encouraging revelation comes from Robert W. Hunt, a professor of materials science and engineering at Rensselaer Polytechnic Institute (Troy, NY). Hunt heads a committee for the World Technology Evaluation Center that the National Science Foundation and other federal agencies have contracted to conduct a two-year, $400,000 study of nanotechnology around the world. Nanotechnology, a rapidly expanding scientific field, is in an early stage of development not unlike that of computer and information technology in the 1950s. Siegel, who coined the phrase "nanophase" materials, explains that new tools are letting scientists and engineers characterize and manipulate materials at the nanoscale level. For instance, he works with materials comprised of common atoms arranged in grains less than 100 nm in diameter--10,000 times smaller than grains in conventional materials. Researchers use them as building blocks to create materials with entirely new properties. Recently, members of Siegel's committee spent a week in Japan and in western Europe visiting sites conducting research on such materials. A report on their findings is due out this spring. E-mail [email protected]
Butterfly wings, beetle horns reveal how bodies develop
Caterpillars treated to stunt the growth of their future hind wings developed into butterflies with abnormally large front wings. At least that's what two Duke University (Durham, NC) biologists have discovered. And they also found that dung beetles treated to stunt the growth of their horns sprouted larger eyes. The discoveries represent more than biological curiosities, Professor of Zoology Fred Nijhoust and postdoctoral fellow Douglas Emlen report. It constitutes, they say, the first clear demonstration that living organisms arise not only through the direct read-out of some genetic recipe, but also through more subtle and mysterious processes of competition between growing body parts for resources. Such tradeoffs,
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