Growth of the nation's economy slowed in the second quarter to weigh the markets down to a lower open with the Dow falling 31 points to 10,435. Nasdaq dropped 10 points to 2241.

On the upside

Power One (Nasdaq: PWER) reversed year ago losses to post a better than expected profit for the second quarter and the company forecast third quarter results ahead of estimates.

Alcatel-Lucent (NYSE: ALU) reported a greater than expected second quarter loss but the telecommunications company affirmed its growth outlook for the second half of the year.

The Food and Drug Administration will allow Geron (Nasdaq: GERN) to conduct the world's first clinical trial of human embryonic stem cell based therapy in human patients.

On the downside

TeleNav (Nasdaq: TNAV) reported higher fourth quarter income that topped analyst estimates but warned that changes to its contract with Sprint (NYSE: S), the company's largest client, may reduce future revenue.

Second quarter earnings surged for Acme Packet (Nasdaq: APKT) and the company lifted its full year outlook but investors expected even greater 2010 results.

MEMC Electronic Materials (NYSE: WFR) reported higher second quarter earnings but the results fell short of expectations and the company warned that it will miss its full year income guidance.

In the broad market, declining issues outpaced advancers by a margin of 7 to 5 on the NYSE and by more than 7 to 5 on Nasdaq. The Russell 2000 which tracks small cap stocks slipped a point to 648.