Showing papers by "Tokyo University of Science published in 1988"

A case report on a minor contamination of nivalenol in cereals harvested in Canada.

Abstract: An investigation for the occurrence of nivalenol (NIV), deoxynivalenol (DON) and zearalenone (ZEN) in cereals (ten wheat, one rye and one corn) harvested in Canada have been carried out using a procedure, which is rapid and sensitive for Fusarium mycotoxins. NIV, DON and ZEN were detected in 4, 9 and 9 out of ten wheat samples, and their average levels in the positives were 23 ng/g, 1257 ng/g and 9 ng/g, respectively. One rye and one corn were also contaminated with a minor amount of NIV. This is the first evidence for the natural occurrence of NIV in cereals grown in Canada, though its level was far less than DON.

Modulation of hormonal induction of tyrosine aminotransferase and glucocorticoid receptors by aflatoxin B1 and sterigmatocystin in Reuber hepatoma cells

Abstract: Employing Reuber rat hepatoma cells, H4-II-E, the effects of aflatoxin B 1 (AFB 1 ) and sterigmatocystin (STC), which exhibit a similar cytotoxity but a marked difference in hepatocarcinogenicity, on the hormonal induction of tyrosine aminotransferase (TAT), on glucocorticoid receptors, and on their nuclear acceptor sites were investigated. AFB 1 strongly inhibited hydrocortisone-inducible TAT activity. The IC 50 value was 0.2 µg/ml. AFB 1 also showed weak inhibitory effects on insulin- and dibutyryl cyclic AMP-inducible TAT activities. In contrast, the IC 50 of STC on hydrocortisone-inducible TAT activity was 3.5 µg/ml, about 10 times higher than that of AFB 1 . Dibutyryl cyclic AMP- and insulin-inductions were not depressed by STC. AFB 1 inhibited the formation of cytosolic glucocorticoid receptor-hormone complexes (GRCs) but STC did not. Moreover, AFB 1 , activated in vitro by the microsomal cytochrome P-450 system, interfered more markedly in the formation of cytosolic GRCs than STC did. Sucrose density gradient analysis of GRCs and Scatchard analysis revealed that AFB 1 and STC mainly impaired glucocorticoid receptors and GRC-acceptor sites, respectively. The present data suggest a marked difference between AFB 1 and STC with regard to the inhibition of hormonal induction of liver specific enzymes.

Sidegating Effects in Inverted AlGaAs/GaAs HEMT

Abstract: Sidegating effects in submicron gate I-HEMTs are reported over a wide range of the drain voltage. A kink in the drain current and the disappearance of the sidegating effect at high drain voltages (3~4 V) are attributed to the hole injection caused by the impact ionization in the channel. The observation of a new type of sidegating effect at higher drain voltages (>4 V) is also reported. The strong drain voltage dependence is explained by the enhanced electron injection into the substrate caused by the higher hole injection.

The effect of the wettability of the injection nozzle on the size of oil droplets in water.

Abstract: The effect of the wettability of an injection nozzle on the size of oil droplets in water has been studied. Dodecane as an oil was dispersed into a continuous water phase through various polymers attached to the top of each single nozzle. The polymer filters used were polyethylene (PE), poly(vinyl chloride) (PVC), poly(vinyl alcohol) (PVA), cellophane (CP), and cotton (CT). The hydrophilic cotton filter is found to be more effective as the injection nozzle than any other hydrophobic polymer filter tested to disperse smaller oil droplets of dodecane into the continuous water phase. The droplet size is reduced with an increase in the hydrogen-bonding force of the polymer-filter surfaces. This may be attributed to the strong adhesion tension between the water molecules and hydrophilic groups of the polymer surface.