STOCKHOLM - U.S. researchers William Kaelin and Gregg Semenza and British molecular biologist Peter Ratcliffe jointly won this year's Nobel Prize in Medicine on Monday for their discoveries of how cells sense and adapt to oxygen availability.Kaelin, 61, is a professor of medicine at Harvard University and an investigator at the Howard Hughes Medical Institute and the Dana-Farber Cancer Institute, while 63-year-old Semenza currently serves as the vascular research program director at the Johns Hopkins Institute for Cell Engineering. Ratcliffe, 65, is a director at the Francis Crick Institut…READ FULL ARTICLE