Showing papers by "Tokyo University of Science published in 1977"

Mode of action of trichothecenes

Abstract: In the present discussion, the author summarized the toxicological and biological features of thirty kinds of trichothecene mycotoxins which are produced by a wide range of Fusarium, Myrothecium and others. The 12, 13-epoxytrichothecenes induce nausea, emesis, vomiting, skin inflamation, leukopenia, diarrhea, hemorrhage in lung and brain, and destruction of bone marrow. Since these toxicological characteristics coincide with a major symptom of intoxicated humans and farm animals induced by consumption of moldy cereals and feeds, the red-mold toxicosis and bean-hulls poisoning in Japan, moldy corn toxicosis in U.S.A., A.T.A., stachybotryotoxicosis and dendrochiotoxicosis in Europe, are originated from a common toxicant, trichothecenes. Orally administered trichothecenes are rapidly absorbed and eliminated into the feces and urine upon deacetylation at C-4 by the microsomal esterase of liver. Biochemical approaches to the mode of action revealed that the trichothecenes are a potent inhibitor of protein and D.N.A. syntheses in eukaryotic cells. Bindings to the eukaryotic polysomes and ribosomes and the subsequent inactivation of ribosomal cycle is responsible for their inhibitory effect to initiation and termination reactions. Microbial approaches revealed that the trichothecenes are mutagenic to yeast cells, but are negative in D.N.A.-attacking ability to Bacillus subtilis and reversion assay with Salmonella typhimurium. Reactivity of the epoxide ring of trichothecenes with S.H.-group of proteins will be discussed in relation to the molecular mechanism of action.

Structural modeling in a class of systems using fuzzy sets theory

Abstract: On the basis of fuzzy sets theory, we propose a method for structuring hierarchy for the several complex problems, and call it Fuzzy Structural Modeling (FSM) method. An important requirement for structural modeling of complex systems is that the necessary data is acquired and organized into a form such that a structural model can be developed. The main purpose of this method is to describe and illustrate a formal procedure for constructing the graphic presentation of the hierarchical arrangement given the necessary information concerning the relation of each element to each other element. The procedure permits an automatic development of the graphic structure that portrays the hierarchy.

Heuristic structure synthesis in a class of systems using a fuzzy automaton

Abstract: A heuristic synthesis method for a class of systems is proposed by using a fuzzy automaton. The transition of system structure is represented by fuzzy relations and the interconnection among subsystems, that is system structure is determined by a heuristic policy. A computational algorithm is given on the basis of a learning system so as to realize the proposed method. Further, in order to avoid to get an ill-posed solution, a necessary condition is given with respect to the fuzzy transition matrix and the initial condition of system. An example is illustrated to show how the proposed method works.