Usain Bolt, the men\'s 100-meter world record holder, will look to defend his world title Sunday. His two archrivals, fellow Jamaican Asafa Powell and Tyson Gay of the U.S., have both pulled out with injuries. In the 100 ?eters, the last of the five finals of the day, there could be an all-Jamaican podium, with Nesta Carter and Yohan Blake all vying for their shot at glory. Americans Justin Gatlin, former world champion returning from a drug suspension, and the reigning U.S. champion Walter Dix will try to crash the Jamaican party.