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Otto Hahn and Lise Meitner at the Kaiser Wilhelm Institute in Berlin, discovered a much longer lived isotope in 1917: protactinium-231 (half-life of 32 670 years).
They identified protactinium-231 by establishing that no known substance could have emitted the alpha particles that were observed and by the actinium produced.
Frederic Soddy and John Cranston also discovered protactinium independently in 1917, at the University of Glasgow, Scotland.
The blood of many lower animals, such as mollusks, cephalopods, gastropods, and decapods, contains respiratory proteins called hemocyanins, which contain copper atoms (but no heme) and appear to bind one oxygen molecule per two copper atoms.
Human serum contains a glycoprotein called ceruloplasmin, the molecule of which contains eight copper atoms; its biological function is still uncertain.