Dinitrophenol (dnp) is an uncoupler that makes the inner mitochondrial membrane leaky to protons. it was used until 1938 as a what?

The four Science Regents exams (Earth Science, Living Environment, Chemistry, and Physics) also include separately-scheduled lab practicals.
In New York, students have the opportunity to take Regents Exams in grades 9-12 and, when appropriate, in grade eight.