The small plastic vial in James ­Thomson's hand contains more than 1.5 billion carefully coddled heart cells grown at Cellular Dynamics, a startup based in Madison, WI. They are derived from a new type of stem cell that ­Thomson, a cofounder of the company, hopes will improve our models of human diseases and transform the way drugs are developed and tested.

It would also appear to be a necessary condition for long duration human space travel.  To read the rest of the article, click here.