Really small (with big implications)

Today's post deals with news of the really tiny.

We'll start at nanoscale -- and that's as big as we'll consider today. (One nanometer, 1 billionth of a meter, is the scale of small molecules. Living cells are no larger than microscale, measured in millionths of meters.)

There's been a fair amount of uncertainty about the health implications of nanoparticles. Why? Much of the allure of nanotech has been that materials often act differently in nanoscale particles than in bulk -- and yet for a lo...