Here are the day’s biggest percentage gainers and losers, along with top volume leaders, among companies with a market cap between $100 million and $750 million:

Biggest percentage gainers:

• Chemgenex Pharm Ltd. (Nasdaq:CXSP), up 30% to $13.95.
• DDI Corp. (Nasdaq:DDIC), up 13% to $5.20
• VanceInfo Technologies Inc. (NYSE:VIT), up 14% to $8.11.

Biggest percentage losers:

• Cheniere Energy Inc. (AMEX:LNG), down 36% to $7.11 on news it reduced its earnings and sales outlook for the full year.
• Aladdin Knowledge Systems Ltd. (Nasdaq:ALDN) down 27% to $15.80 on news that it reported first-quarter earnings that missed analysts’ estimates by a penny and news that it lowered its fiscal 2008 earnings estimate.
• Silver State Bancorp (Nasdaq:SSBX), down 17% to $5.56.

Volume leaders:

• Packeteer Inc. (Nasdaq:PKTR), 14,591,639 million shares traded versus the average of 356,670 shares.
• Cheniere Energy Inc. (AMEX:LNG) 6,655,424 shares traded versus the average of 984,475 shares.
• SiRF Technology Holdings, Inc. (Nasdaq:SIRF) 3,004,253 shares traded versus the average of 4,810,510 shares.

The day saw 28 small-cap stocks set 52-week lows, while 16 small caps established a 52-week high.