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 firstname.lastname@example.org .
Engineers throughout the US are in the midst of celebrating Engineers Week. But the celebration extends beyond the country’s borders, and even beyond the Earth itself; the crew of the International Space Station joined the festivities, too!
Many engineering professionals have come to view CAD as something of a commodity, not an area where much innovation can be expected. CAD tools continue to get better, however, with software delivering powerful capabilities for the evolving product design process.
Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.