American Technology ( ATCO), meanwhile, traded some 23% higher to $3.98 after saying the U.S. Navy and Army chose the San Diego-based company's LRAD 500 acoustic hailing and warning device for small vessels and vehicles. Children's footwear maker Stride Rite ( SRR), which agreed to an $800 million takeout by Payless ShoeSource ( PSS), surged 30.9% to $20.21 and provided strong support to the S&P SmallCap 600, but the index still weighed under the broader market's afternoon slide. The index slipped 2.09 points to 434.22. Among those pulling down the tracker was Minneapolis medical-device maker Possis Medical ( POSS), which plunged 9.8% to $12.09 after breaking even for the quarter ended April 30 to fall a nickel short of Thomson Financial's per-share earnings consensus for the quarter ended April 30. Likewise for fellow components Pep Boys ( PBY), an auto-parts retailer, and Maximus ( MMS), a business-services firm. Pep Boys slid 5.6% to $18.82 after coming in below sales estimates for the quarter ended May 5, and Maximus was cut to hold from buy at Stifel Nicolaus, pressuring shares down 4.2% to $41.65. Elsewhere in negative territory, Vion Pharmaceuticals ( VION) took a 57.4% nosedive to 86 cents after the New Haven, Conn., biotech halted a late-phase study of leukemia drug Cloretazine "pending a detailed review of all of the data from the trial." TRM ( TRMM), an Oregon-based purveyor of ATM and photocopy services, tumbled 25.5% to $1.81 after announcing dwindling fourth-quarter revenue and a widening loss vs. last year, as well as the resignation of Chief Executive Jeffrey Brotman, who will stay on as a non-executive chairman. His CEO role will be assumed by the current chief operating officer, Richard Stern, as of June 15.