Pharmacologist Tu Youyou attends a award ceremony in Beijing, November 15, 2011. William Campbell, Satoshi Omura and Tu jointly won the 2015 Nobel prize for medicine or physiology for their work against parasitic diseases, the award-giving body said on October 5, 2015. Picture taken November 15, 2011. REUTERS/Stringer CHINA OUT. NO COMMERCIAL OR EDITORIAL SALES IN CHINA. – RTS32DH