Dirty bombs are one of the biggest threats to the world's urban populations. Now an American molecular biologist has developed a drug that may protect against the effects of radioactivity. Military officials are thrilled, and the discoverers could make billions. On Friday afternoons, as the Sabbath approaches and the sun hangs low in the sky over the Mediterranean, the Restaurant Turquoise north of Tel Aviv is a carefree oasis. Every seat in the place is taken, and the crowd is in high spirits. Only one patron, Yacov Reizman, seems serious as he glances at a stack of documents -- a...