大象传媒

Polymers in Dentistry
X-rays are a routine tool in your dentist鈥檚 armoury, but what if there were a cheap alternative that could find tooth decay even earlier, and without the need to take a dose of radiation?

A collaboration between Heriot-Watt Biomedical Textiles Research Centre and the Dundee University Dental Health Services Research Unit has come up with a device that could potentially revolutionise the search for dental caries in your teeth. A dental cavity has a lower electrical impedance than surrounding healthy tooth, and a special probe, thin and flexible enough to be placed on the surface enamel, can map the areas of decay with greater accuracy than an x-ray.

Dr Alex Fotheringham of Heriot-Watt University tells Quentin how his team came up with just the right material, and Chris Longbottom of Dundee describes how it works and the potential benefits.

Einstein Tests
As Radio 4 prepares for its short season of science plays on Saturdays, starting with Terry Johnson鈥檚 Insignificance, recounting a fictional encounter between Albert Einstein and Marilyn Monroe, Quentin talks to two scientists who are looking to stars of another sort to test Einstein鈥檚 theories.

For three years, a three-quarter billion dollar satellite, Gravity Probe B, has been trying to measure the effect of the spinning Earth on the surrounding space-time. And even as those results are awaited, its principal scientist, Stanford University鈥檚 Francis Everitt, is planning another satellite that will repeat Galileo鈥檚 experiment of dropping weights from the Tower of Pisa, high up in orbit.

Quentin hears the details from Francis Everitt and his UK collaborator Tim Sumner.