A 4 percent decline in biotechnology stocks on Wednesday sent the Nasdaq Composite Index (.IXIC) to its largest one-day loss in nearly a year, and some investors are betting that the once-hot sector has further to fall. Short interest has risen in a number of biotech names perceived as vulnerable to a selloff after a rally that has sent the Nasdaq Biotechnology Index (.NBI) up 42 percent over the last year even after this week’s declines. Overall, a screen of about 1,650 mid-cap U.S.