Nikkei Wednesday closed 0.55 percent lower as sentiment was dampened by emerging concern over China's economic growth. The 225-issue Nikkei Stock Average ended 55.50 points, or 0.55 percent, lower than Monday at 10,086.49. The broader Topix index of all First Section issues on the Tokyo Stock Exchange closed down 9.57 points, or 1.10 percent, at 858.78. The financial markets were closed Tuesday for a national holiday. Decliners included the oil and coal products, banking and machinery sectors. Gainers included the retail, pharmaceutical and metal products sectors. The turnover was about 1,356.5 billion yen (about 16.23 billion U.S. dollars).