Complex sentence: Unlike the changing slate of national, regional and on-site PHS administrators, doctors, and researchers, Rivers stayed at Tuskegee University, becoming the only study staff person to work with participants for the full 40 years.
Split into simpler sentences: Unlike the changing state of national, regional and on-site PHS administrators, doctors, and researchers, Rivers stayed at Tuskegee University. She was the only study staff person to work with participants for the full 40 years.