Complex sentence: He was Chairman of the Department of Nutrition at UNC from 1990-2005, directing the largest and most highly ranked department of nutrition based in a school of public health and school of medicine in the country.
Split into simpler sentences: He was Chairman of the Department of Nutrition at UNC from 1990-2005. He directs the largest and most highly ranked department of nutrition based in a school of public health and school of medicine in the country.