He headed the Theoretical Biology and Biophysics group at Los Alamos from 1974 to 1990 .
Bell 's interests turned to biology in the 1960s , creating quantitative models in immunology .
Bell headed the Theoretical Biology and Biophysics group at Los Alamos from 1974 to 1990 .
Bell 's interests turned to biology in the 1960s , creating quantitative models in immunology .