The stock market currently is focused on new stents being developed by Guidant (nyse: GDT - news - people ) and Medtronic (nyse: MDT - news - people ), but these stents are based on the same idea as those that are currently on the market: They are made of steel, coated with a polymer.

FORBES: The New Stent In Town

Fuel cells come in several varieties, but the heart of the sort developed by Ballard is a polymer membrane coated on either side with platinum electrodes (the platinum also acts as a catalyst).

ECONOMIST: Fuel cells hit the road | The