Barry Bonds said Tuesday he hasn't heard yet from former Sen. George Mitchell in his independent investigation of steroids in baseball. Mitchell was appointed in March by commissioner Bud Selig to head the league's investigation into steroids. He has already contacted some members of the Giants' coaching staff. Bonds, who has always denied using performance-enhancing drugs, said he is determined to stay upbeat despite his decreased production this season, a sore, tired body, and his off-the-field issues. "I'm doing good, ain't I? I'm going to be a positive person no matter what," Bonds said. "As long as my health is good and my family's happy, I'm going to be happy."