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Science Friday > Archives > 2001 > March > March 2, 2001:

Hour One: Superconducting / Stem Cells

This week, Japanese researchers published a research article in the journal Nature detailing the discovery of a new superconducting material. That in itself isn't big news - many researchers are looking into materials that, at certain temperatures, lose all resistance to electrical conductivity. What is big news, however, is that the newly discovered superconductor, magnesium diboride (MgB₂) is a stable, metallic compound, is readily available from chemical supply stores, and that it becomes superconducting at temperatures higher than other metallic compounds (39K).

There are many superconducting materials that operate at higher temperatures, including the copper oxide superconductors. Some operate even at temperatures warmer than liquid nitrogen. However, the new finding has touched off a flurry of activity in the physics community, as researchers race to understand fully the mechanism through which magnesium diboride superconducts, methods to improve its performance, and ways of building useful structures from the material. We'll get a rundown on some of the research, and find out why some physicists say that this is such a big deal.

Then we'll turn from the world of superconductors to the world of stem cells - biological entities that may have super properties of their own. Certain cells in developing embryos have the potential to become any cell in the body - from skin, to brain tissue, to heart, to bone. In 1997, scientists managed to isolate some of these powerful cells and grow them in a petri dish, making it possible for scientists to study them more thoroughly.

In the years since then, scientists have been trying to learn the secrets of coaxing these cells into developing into specific forms of tissue, and how this ability might be exploited to cure degenerative diseases. Other researchers have been looking for ways to use adult cells in similar ways, though such cells seem to have their destiny more solidly defined and are harder to manipulate.

Stem cell research raises many ethical issues, however. Because the most promising source of these tissues is developing embryos, and removing the cells destroys the possibility that the embryo will develop into a viable fetus, stem cell research has sparked protests from anti-abortion protesters. Currently, Health and Human Services Secretary Tommy Thompson is weighing whether or not federal funds may be used to support such research. We'll take a look at some of the latest findings in stem cell research, and at some of the ethical arguments surrounding the work.

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Guests:
Robert Cava
Professor, Chemistry and Materials Science
Princeton University
Princeton, New Jersey

Dr. Evan Snyder
Assistant Professor, Neurology
Harvard Medical School
Neurology, Pediatrics and Neurosurgery
Children's Hospital
Boston, Massachusetts

Glenn McGee
Editor-in-Chief, American Journal of Bioethics
Assistant Professor of Bioethics, Center for Bioethics
University of Pennsylvania
Philadelphia, Pennsylvania

Books/Articles Discussed:

"Boron Isotope Effect in Superconducting MgB2" S. L. Bud'ko, G. Lapertot, C. Petrovic, C. E. Cunningham, N. Anderson, and P. C. Canfield.Physical Review Letters, February 26, 2001, Volume 86, Issue 9 pp. 1877-1880. "Superconductivity at 39K in magnesium diboride," Jun Nagamatsu, Norimasa Nakagawa, Takahiro Muranaka, Yuji Zenitani, Jun Akimitsu. Nature 410, 63-64, 1 March 2001. (find more SciFri books here)

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Related Links:
Superconductors

NIH: News: Stem Cell Information
NIH Fact Sheet on Human Pluripotent Stem Cell Research Guidelines