activator(redirected from tPA, TPA)
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A substance that increases the effectiveness of a rubber vulcanization accelerator; for example, zinc oxide or litharge.
A trace quantity of a substance that imparts luminescence to crystals; for example, silver or copper in zinc sulfide or cadmium sulfide pigments.
A molecule that modifies a repressor in a way that enables it to stimulate operon transcription.
1. A substance which accelerates a chemical reaction but appears to remain unchanged itself.
2. A hardener that accelerates cure of adhesives either with or without heat. Used primarily with synthetic resins.