[img]http://d.yimg.com/a/p/ap/20100412/capt.5d2e217acb8147eb97d12ffbb75ce9f3-5d2e217acb8147eb97d12ffbb75ce9f3-0.jpg?x=116&y=130&q=85&sig=71d_Mqqhf3J92hxwrWKgVQ--[/img]AP - President Barack Obama's nuclear summit has paid early dividends: China's agreement to work with the U.S. on possible sanctions against Iran and Ukraine's decision to rid itself of nuclear bomb-making materials.