ST. PAUL, Minn., July 9 (UPI) -- Efforts to train robots to perform certain kinds of surgical procedures without human help have reached a "critical milestone" with a successful gallbladder removal procedure on a pig cadaver, researchers reported Wednesday. Medical robotics experts at Johns Hopkins and Stanford universities revealed in a new study they have "significantly" pushed the envelope on what is possible for robots to do in the operating room without human doctors at the controls, using