Self-described "nerd" Caio Borralho quit his chemical engineering studies to become a professional mixed martial arts (MMA) fighter, part of a new generation looking to reinvigorate the sport in Brazil, home of legendary champions.Brazil may be the land of football, but the country was instrumental in the rise of the UFC, thanks to international interest in Brazilian jiujitsu -- a reinvention of the ancient Japanese martial art -- and "vale tudo," a violent, no-holds-barred combat sport.