Dynasil Corporation (Nasdaq: DYSL) shares skyrocketed 70.2% to $6.62, on volume of 156,500 shares, towering over its average of 9,172 a day, after it announced that its research division was granted additional U.S. patent claims for advances in a detector material capable of responding independently to both neutron and gamma radiation.

Citigroup Inc. (NYSE: C) was a volume leader in early trading on Wednesday, dealing in 114.7 million shares, against a full-day average of 487.6 million. Share prices eased 1.6% to $4.35, after C announced the hiring of former StanChart banker Martin Lovegrove to head its energy services division.

Xoma Ltd. (Nasdaq: XOMA) shares were off 28.5% to $3.59, on volume of 2.6 million, catching up on a daily average of 4.2 million, a day after the company said a diabetes-treatment candidate did not yield better results than a placebo in a study.