Rosalyn Yalow: Notable women in scienceIn 1977, Rosalyn Yalow became the second woman to win a Nobel prize in medicine for co-developing radio-immunoassay (RIA), a groundbreaking technique that uses radioactive isotopes to quickly and precisely measure concentrations of hormones, vitamins, viruses, enzymes, drugs, and hundreds more substances. The technique is so sensitive that it can detect a teaspoonful of sugar in a body of water 62 miles long.