Associated Press: In April, a group of 10 doctors urged that Dr. Mehmet Oz be removed from Columbia University’s medical faculty, accusing him of promoting “quack treatments.” His show, introduced to the world by Oprah Winfrey, has lost half its viewers over the past five years. “Heal thyself” is now the goal, as Oz tries to recalibrate and save his program, which is beginning a seventh season. He privately sought feedback this summer.