Complex sentence: From 1952 to 1960 Dr. Rahbar pursued mainly clinical activities in Abadan and Tehran but returned to academic life as a postdoctoral fellow in 1959 and soon after his PhD was promoted to Assistant Professor in 1963 and to Associate Professor in 1965 in the Department of Immunology.
Split into simpler sentences: From 1952 to 1960 Dr. Rahbar pursued mainly clinical activities in Abadan and Tehran returning to academic life as a postdoctoral fellow in 1959. Soon after earning his PhD, he was promoted to Assistant Professor in 1963 and to Associate Professor in 1965 in the Department of Immunology.