Erasing all its initial gains, the Sensex at the Bombay Stock Exchange stood 67 points, or 0.4 percent in negative territory, at 18,079, in afternoon deals, a short while ago, as investors resorted to mild profit-booking, amid weak regional bourses. Earlier in the morning, however, the Sensex had opened 57 points, or 0.3 per cent in the positive zone, at 18,202 on selective buying by funds.Elsewhere in Asia, key stock indices in China, Hong Kong, Indonesia, Singapore, South Korea, and Taiwan were down by between 0.1 percent and 1 percent, as higher oil prices and weak euro-zone data sparked concerns about global growth.