Tokyo stocks were mixed Thursday morning, as buying on growing hopes for interest rate cuts in the United States amid cooling inflation was offset by selling of exporters hurt by a firming yen against the U.S. dollar. The 225-issue Nikkei Stock Average rose 283.84 points, or 0.74 percent, from Wednesday to 38,669.57. The broader Topix index was down 7.19 points, or 0.26 percent, at 2,723.69. The dollar briefly dipped to the upper 153 yen zone in Tokyo, as U.S. data showing decelerating inflation in April reinforced expectations the Federal Reserve will cut interest rates this year. At noon, th…