Artifical diamonds; anthrax attacks; “AutoTune”; profile of Luis von Ahn.

Breakthroughs in the engineering of artificial diamonds; the science that went into solving the deadly post-9/11 anthrax attacks and the ingenious technique researchers developed to pinpoint the source; "AutoTune," the controversial computer pitch-correction software that turns sour notes into sweet ones; and a profile of computer scientist Luis von Ahn.