with reference to the nature, number and position of the heteroatoms. These included the naphtho and benzo derivatives of pyridocarbazole and beta-carboline, heteroaromatics with sulfur, arsenic or selenium replacements. These were either alone or in association with nitrogen, as well as sulfur and nitrogen containing pseudoazulenes. A series of hydrocarbon-like polynuclear lactones were explored with the intent of establishing a connection between polynuclear aromatics and aflatoxins. Such studies of heteroatomic polynuclears led him to propose a "newer picture" of a carcinogenic hydrocarbon, helping the generalise the classical K-region hypothesis. He contributed to studies on the carcinogenicity of 4-nitroquinoline-N-oxide derivatives, the production of plant tumors by a nitrosamine. He also studied metabolism and protein binding of polynuclears and the effect of the binding o DNA replication and transcription, testing the effect of various carcinogens on the hatching of shrimp eggs. From the mid-1960s onwards, Bửu Hội increasingly turned his focus to the structural facets of polynuclears which determine their ability to induce microsomal enzyme synthesis, in particular involving zoxazolamine and dicoumarol hydroxylation. Aside from his study of fundamental organic chemistry, chemical carcinogenesis and chemotherapy of leprosy and tuberculosis, Bửu Hội's team also conducted research into a wide range of issues of biological and therapeutic interest. These included the synthesis and testing anti-inflammatory non-steroid compounds, substituted sex hormones, anti-coagulant substances and their potentiation, antidiabetic agents, treatment of hypertension by methyl-DOPA, antioxidants and the chemophylaxy of aging and the toxicity of dioxine among others. Professional appointments In 1947, Hồ Chí Minh named him as the Rector of the University of Hanoi. He later served as science advisor to Diệm and was appointed in 1960 as the Director of the Atomic Energy Establishment of Vietnam. In this capacity, he was a key figure in the establishment of an Atomic Energy Research Center. Political pursuits Mid 1940s to Early 1960s While in Paris, Bửu Hội had not limited his activities to scientific research. He had worked with Hồ Chí Minh's Vietminh to form the Democratic Republic of Vietnam which sought to establish independence from its formation in September 1945. His international reputation, generated by his scientific achievements, lent prestige to the Hồ Chí Minh government. Hội later broke off ties in 1950 when the Communists imposed a dictatorship on the resistance movement.[12] In the early 1950s, Bửu Hội traveled to the United States. After the disruption of the Second World War, the president of the