Two companies - Gaithersburg, Md.-based Emergent BioSolutions Inc., and Lexington, Mass.-based ActivBiotics Inc. - filed for their IPOs this week, hoping to raise as much as $86.25 million and $46 million, respectively. Both companies were in SEC-imposed quiet periods Tuesday. If their IPOs are completed, their stocks would be listed on the Nasdaq National Market under "EBSI" for Emergent and "ACTV" for ActivBiotics. (BioWorld Today)