Kenneth N. Trueblood, 78, a UCLA chemistry professor and administrator who was an early researcher of DNA. A native of Dobbs Ferry, N.Y., who was educated at Harvard and Caltech, Trueblood specialized in crystallography and worked throughout his life on the structure of molecules. He was co-author of "Crystal Structure Analysis: A Primer" in 1972 and editor of "Dorothy Hodgkin and Linus Pauling--A Tribute" in 1995. Under a grant from the U.S. Public Health Service in the late 1950s, Trueblood studied the arrangement of components of deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), which are involved in heredity. Trueblood also was a pioneer in using computers for structural analysis. He joined the UCLA faculty in 1949, chaired the chemistry department from 1965 to 1970 and again in 1990-91, was dean of the College of Letters and Science from 1971 to 1974 and chaired the Academic Senate in 1983-84. Trueblood continued his research until his death. Among his honors were a Fulbright Award, a Guggenheim Fellowship, the Fankuchen Memorial Award of the American Crystallographic Assn., the first UCLA Distinguished Teaching Award, and the national award for excellence in teaching from the Manufacturing Chemists Assn. On May 7 in Los Angeles of cancer.