The present invention relates to stable polymer systems comprising anionic and modified polyamine polymers. The hypodermic needle assembly according to the present invention includes a needle, a needle hub, and a safety spring clip assembly, the safety spring clip assembly being configured to automatically launch from the needle hub and slide along the needle to shield the needle tip, thus preventing accidental contact with the needle tip. Compositions that include recombinant vaccinia and variola polypeptides are also disclosed. The placard is retained at a position is visible to a user. The inboard end of the rod is axially slidably engaged with the inboard rod to accommodate variances in the relative positions between the outboard and inboard recliners due to build tolerances in the seat assembly and the vehicle.