The Nikkei stock index rose Wednesday morning, supported by buying of chip-related and technology shares following an overnight rally of their U.S. counterparts. The 225-issue Nikkei Stock Average rose 241.16 points, or 0.62 percent, from Tuesday to 39,178.70. The broader Topix index was down 0.22 point, or 0.01 percent, at 2,698.93. The U.S. dollar remained firm in the lower 148 yen range in Tokyo as expectations for sharp interest rate cuts by the U.S. Federal Reserve receded, supporting dollar-buying against the yen. At noon, the dollar fetched 148.27-29 yen compared with 148.15-25 yen in N…