The Nikkei stock index rose above the 42,000 mark for the first time Thursday, boosted by buying of Apple Inc. suppliers and other technology issues as well as optimism about corporate earnings. The 225-issue Nikkei Stock Average gained 347.85 points, or 0.83 percent, from Wednesday to 42,179.84, after climbing to an all-time intraday high of 42,426.77. The broader Topix index was up 19.10 points, or 0.66 percent, at 2,928.30, also a record intraday high. The U.S. dollar remained solid in the upper 161 yen range in Tokyo, as rising U.S. and Japanese stocks prompted investors to sell the yen, s…