Showing papers by "Tokyo University of Science published in 1978"

Parallel Two-Phase-Flow-Induced Vibrations in Fuel Pin Model

Abstract: This paper reports the experimental results of vibrations of a fuel pin model —herein meaning the essential form of a fuel pin from the standpoint of vibration— in a parallel air-and-water two-phase flow. The essential part of the experimental apparatus consisted of a flat elastic strip made of stainless steel, both ends of which were firmly supported in a circular channel conveying the two-phase fluid. Vibrational strain of the fuel pin model, pressure fluctuation of the two-phase flow and two-phase-flow void signals were measured. Statistical measures such as power spectral density, variance and correlation function were calculated. The authors obtained (1) the relation between variance of vibrational strain and two-phase-flow velocity, (2) the relation between variance of vibrational strain and two-phase-flow pressure fluctuation, (3) frequency characteristics of variance of vibrational strain against the dominant frequency of the two-phase-flow pressure fluctuation, and (4) frequency characteristics o...

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, vomiting, skin inflammation, leukopenia, diarrhea, haemorrhage 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 USA, alimentary toxic aleukia (ATA), stachybotryotoxicosis and dendrodochiotoxicosis in Europe, are originated from a common toxicant, trichothecenes. Orally administered trichothecenes are rapidly absorped and eliminated into the feces and urine upon deacylation at C-4 and C-8 by the microsomal esterase and others. Biochemical approaches to the mode of action revealed that the trichothecenes are a potent inhibitor of protein and DNA syntheses in eukaryotic cells. Binding 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 DNA-attacking ability to Bacillus subtilis and reversion assay with Salmonella typhimurium. Reactivity of the epoxide ring of trichothecenes with SH-group of proteins will be discussed in relation to the molecular mechanism of action.

A Broadband and Higher-Power Superconducting Quantum Magnetometer for the Small Signal A-D Converter

Abstract: We describe several types of wide operations and performances of a Superconducting Quantum Magnetometer at 10 GHz and higher output power levels (a microwave SQUID) for a fast and small signal A-D converter. Direct exhibition and counting of the high-speed Q-patterns from a higher-power SQUID have benn demonstrated up to a frequency region above 10 MHz by improving the post-detection system. These results give the best figure of merit so far reported far a microwave SQUID.