Top Percentage Gainers and Losers as of 3:30pm 4/13/11 (ZOOM, GRM, SLGN, DCTH, QTM, IRBT, SIFY, DGW, INVE, YUII, CSR, TRGL, CIGX, MSB, KNDI, CNIT)

Best

1) Zoom Technologies (NASDAQ: ZOOM): Trading up 39.4% from yesterday's close to $4.32. The company acquired new patent licenses from Qualcomm (NASDAQ: QCOM), which will allow the company to develop new mobile phones for the global market. Shares had been up as much as 54% earlier in the session.

2) Graham Packaging Company (NYSE: GRM): Trading up 30.7% from yesterday's close to $21.84. Silgan Holdings (NASDAQ: SLGN) announced that it will purchase the company for the equivalent of $19.65 per share in cash and stock.

3) Delcath Systems (NASDAQ: DCTH): Trading up 20% from yesterday's close to $8.71. The company reported that it has received approval to market and sell its Hepatic Chemosat system in Europe.

4) Silgan Holdings (NASDAQ: SLGN): Trading up 15.8% from yesterday's close to $42.67. Silgan announced that it will be purchasing Graham Packaging Company (NYSE: GRM) for the equivalent of $19.65 in cash and stock.

5) Quantum Corporation (NYSE: QTM): Trading up 16.42% from yesterday's close to $3.09. The company reached an agreement with NetApp (NASDAQ: NTAP), which will Quantum to use NetApp's worldwide sales network to sell its software.

Other notable movers

iRobot (NASDAQ: IRBT): Up 13.79% from yesterday's close to $35.81.

Sify Technologies (NASDAQ: SIFY): Up 12.47% from yesterday's close to $5.14.

Duoyuan Global Water (NYSE: DGW): Up 9.17% from yesterday's close to $3.62.

Worst

1) Identive Group (NASDAQ: INVE): Trading down 34.5% from yesterday's close to $3.73. A negative article at Seeking Alpha has the stock down. Shares reached a 52-week high in yesterday's session.

2) Yuhe International (NASDAQ: YUII): Trading down 19.8% from yesterday's close to $5.34. Shares had started out the day in positive territory.

3) China Security & Surveillance Technology (NYSE: CSR): Trading down 11.69% from yesterday's close to $4.08. A negative article from The Motley Fool highlighting potential problems regarding the company's cash flow is taking its toll.

4) Toreador Resources (NASDAQ: TRGL): Trading down 9.9% from yesterday's close to $7.79. Stock has broken to a new six month low in today's session.

5) Star Scientific (NASDAQ: CIGX): Trading down 8.7% from yesterday's close to $3.13. The stock has lost nearly 34% over the past seven trading sessions.

Other notable movers

Mesabi Trust (NYSE: MSB): Down 8.15% from yesterday's close to $35.50.

Kandi Technologies (NASDAQ: KNDI): Down 6.56% from yesterday's close to $2.28.

China Information Technology (NASDAQ: CNIT): Down 6.61% from yesterday's close to $2.41.