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Past Shows
April 9, 2005
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Polio Vaccine's 50th Anniversary
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A child afflicted with polio is treated in an iron lung - Courtesy, WHO
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In the first half of the 20th century, polio raged through North America, leaving playgrounds empty and parents consumed by fear, as more and more children were crippled or killed by the disease. But on April 12, 1955, the polio vaccine became a reality, promising an end to the suffering. That was the day American scientist Dr. Jonas Salk announced the successful results of the first major field trial of the vaccine. Dr. Salk will always be remembered as the man who saved the children. But producing vaccine in a test tube was one thing, making enough to inoculate an entire population was quite another, and the solution to that problem came from the Connaught Medical Research Labs at the University of Toronto. The Canadian involvement in the eradication of polio has been the subject of Dr. Christopher Rutty’s research for many years. Dr. Rutty is Canada’s leading polio historian.
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Sea Salt and the Maya
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A wooden paddle recovered at the site of the Mayan saltworks - Copyright, PNAS
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The cities of classic Maya had a problem. Salt was scarce in the highland, where the cities were found, but essential for daily life. So, a long-standing question has been where they would have found readily available sources of the mineral. Dr. Heather McKillop, the William G. Haag professor of archaeology at Louisiana State University, has answered that question. She's found a lagoon on the southern coast of Belize where the Maya produced salt on an industrial scale. She says, this represents the presence of a Mayan middle class, who traded their goods up the river to the central cities.
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Homing Fish
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A damsel fish found after responding to the sound of the reef - Copyright Science Magazine |
The trouble with being a young fish, destined for life on a coral reef, is that's not where you start out. Young coral fish spend their early days in the deeper parts of the ocean. So they need to find their way back to the reef. Up until now, how they find their way to the reef has been a mystery. Dr. Stephen Simpson, a tropical fish ecologist from the University of Edinburgh, has discovered reef fish use sound to bring them home. They listen to the noises made by shrimp and fish living on a reef, to navigate to their new residence.
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Chinese Stone Axes
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A corundum stone axe from ancient China might have been buffed with diamond dust - Courtesy, Peter Lu |
Chinese stone artifacts from the Neolithic period (4000-3500 BC) are a lot more sophisticated than anything produced in Europe or North America at the same time. But Peter Lu, a Ph.D student at Harvard University's Physics Department, has found that some of these ancient Chinese stone artifacts are made of corundum. Corundum is the second hardest material on earth, which would make these stone artifacts much more difficult to manufacture and polish than the more commonly used jade. But these artifacts have been polished to a shine comparable to modern-day silicon wafers. The only way this is possible, according to Mr. Lu, is to use a material harder than corundum - which leaves only one possibility: diamond. Experts usually date the use of corundum and diamond much later than this, so the finding could change what we think of the technical abilities of the Neolithic Chinese.
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Undead Bone
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Radiographic images of bone implants in a mouse - Courtesy, Edward Schwarz |
Dr. Edward Schwarz wants to bring the dead back to life. What he's interested in doing is improving bone transplants, in which dead bone from cadavers is used to replace diseased bone in living humans. These transplants work today, but there are problems with transplanting dead bone. Unlike living bone, it can't repair itself, so it can break down and wear out over time, eventually requiring another transplant, or even necessitating the amputation of a limb.
But Dr. Schwarz thinks he has a solution to this problem. He's developed a secret formula for bringing dead bone back to life, using gene therapy. His formula works in mice, and might soon be ready for tests in humans. Dr. Schwarz is an Associate Professor of Orthopaedics at the University of Rochester.
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