Takashi Uesugi

A tandem radio‐frequency plasma torch

The flow and temperature fields in a tandem radio‐frequency (rf) plasma torch were calculated. The method employed here is based on our previous rf plasma model. The flow and temperature fields of this tandem plasma show similar features to those of a dc‐rf hybrid plasma, and the carrier gas can be injected into the high‐temperature region (∼9000 °C) of the second plasma by regulating the linear velocity of the sheath gas. As might be expected, the derived results suggest that the tandem plasma has a possibility to give higher efficiencies for practical processing than conventional rf plasmas. A new type of tandem rf plasma torch was designed based on the results of the calculations. The stability of this plasma was examined under various conditions. Thus, a stable plasma could be maintained even when carrier gas of high flow rate (∼5 l/min of H2) was injected into the top of the second plasma. These theoretical and experimental investigations showed that the tandem plasma torch is an effective reactor fo...

Studies on the biliary excretion mechanism of drugs. I. Biliary excretion of azo dyes in the rat.

Abstract The mechanism of biliary excretion of the azo dyes, Azorubin S (AS), Amaranth (AM) and New Coccine (NC), in rats was investigated. It was observed that these azo dyes have an apparent transport maximum (Tm) for their biliary excretion. Further, the biliary excretion of these dyes was markedly depressed by phenolphthalein glucuronide (PPG) and probenecid, which are considered to be actively excreted into bile. The results, therefore, suggest that the biliary excretion of these dyes in rats involves an active transport process.

Photoconductive Amorphous Silicon-Carbide Produced by Intermediate Species SiF2 and CF4 Mixture

A new type of amorphous silicon-carbide film is produced by the glow discharge decomposition of an intermediate species SiF2, CF4 and H2 gas mixture. Optical band gap and photoconductive properties of this film are measured as a function of carbon content. It is found that the optical band gap can be increased up to 2.2 eV by increasing carbon content without apparent degradation of film properties such as photoconductivity and photosensitivity.

The effect of Sudan III on drug metabolizing enzymes

We have examined the induction of drug metabolizing enzymes in rat liver microsomes by azo dye, 1-(p-phenylazophenylazo)-2-naphthol (Sudan III). Marked increases were observed in the levels of cytochrome P-448 as well as in p-nitroanisole O-demethylase (p-NAD), amaranth (AR) and neoprontosil reductases (NPR) and 7-ethoxycoumarin O-deethylase (ECD) activities. On the other hand, aminopyrene N-demethylase activity was not significantly increased. Further, induced ECD activity was inhibited 90% by a specific antibody against cytochrome P-448 while the inhibition observed with an antibody against cytochrome P-450 was less than 25%. Simultaneous administration of Sudan III and 3-methylcholanthene (3-MC) induced cytochrome P-448 up to a level brought about by either Sudan III or 3-MC treatment alone. In contrast, Sudan III did not induce cytochrome P-448 in the 3-MC insensitive DBA/2 mouse. Solubilized microsomes from Sudan III-treated rats showed an identical sodium dodecyl sulfate polyacrylamide gel electrophoretic (SDS-PAGE) pattern with those from 3-MC-treated animals. It is concluded that the cytochrome P-448 induced in liver by Sudan III is very similar to that induced by 3-MC. Sudan III also induced UDP-glucuronyltransferase activity towards 1-naphthol and estradiol. It did not induce NADPH-cytochrome c reductase, nor any of the enzymes which constitute the microsomal electron transport chain except for cytochrome P-448.

Study of bilirubin metabolism by high-performance liquid chromatography: Stability of bilirubin glucuronides

The stabilities of bilirubin (BR) glucuronide, monoglucuronide (BMG), and diglucuronide (BDG) were studied under various conditions by HPLC. In aqueous media, BMG showed a pronounced lability and was easily transformed into equimolar BDG and BR. It was proved by direct analysis of tetrapyrrole isomers that BDG and BR were formed from dipyrrole exchange of BMG molecules. All reducing agents examined (sodium ascorbate, cysteine, GSH, dithiothreitol, NADH, and NADPH) suppressed the transformation of BMG into BDG and BR. Bovine serum albumin and rat liver cytosol fractions also stabilized BMG strongly. BDG was fairly stable in aqueous media as compared with BMG. When BMG was incubated both with and without liver plasma membranes (N2 fraction) from Wistar rats, the formation rates of BDG and BR in both incubation mixtures were exactly the same. The composition of BDG and BR isomers was the same in both mixtures. Also, heat denaturation of the plasma membranes did not affect formation rates. Moreover, the reaction was completely inhibited by sodium ascorbate. These findings indicate that rat liver plasma membranes have no enzyme activity for BDG formation from BMG.

The Staebler-Wronski Effect in Hydro-Fluorinated Amorphous Silicon Prepared Using the Intermediate Species SiF2

The change in conductivity produced by irradiation with light, the so-called Staebler-Wronski effect (S-W effect), was studied experimentally in a new type of hydro-fluorinated amorphous silicon (s-Si:F:H) prepared from a mixture of the intermediate species SiF2 and gaseous H2. The magnitude of the S-W effect was observed as a function of the light intensity and the Fermi-level position. It was found that the S-W effect in the new a-Si:F:H is much smaller than that in conventional hydrogenated amorphous silicon (s-Si:H) prepared from gaseous SiH4, and that the magnitude of the S-W effect is a function of the substrate temperature during deposition.

Properties of Hydro-Fluorinated Amorphous Silicon-Carbide Produced by Intermediate Species SiF2

A new type of hydro-fluorinated amorphous silicon-carbide (a-SiC:F:H) film was produced by the glow-discharge decomposition of intermediate-species SiF2, H2 and CF4 gas mixture or SiF2, H2 and CH4 gas mixture. Boron and phosphorus were added to this a-SiC:F:H by mixing B2H6 and PH3 with the gas mixtures. The optical, structural and electrical properties of the a-SiC:F:H films were studied experimentally, and it was found that the optical band gap of a-SiC:F:H can be increased up to 2.2 eV by increasing the carbon content without apparent degradation of film properties such as the photo-conductivity or photo-sensitivity, and also that the conductivity of impurity-doped a-SiC:F:H can be increased above that of the similar hydrogenated amorphous silicon-carbide (a-SiC:H) produced from a CH4 and SiH4 gas mixture.

High-performance liquid chromatographic determination of sulphobromophthalein and its conjugates.

A simple, sensitive and selective high-performance liquid chromatographic method for the determination of sulphobromophthalein and its mercaptide conjugates in rat bile was developed. These pigments, which have an absorption maximum at 580 nm in alkaline solution, were separated isocratically on an alkali-resistant ODS column by paired-ion chromatography. Analysis of bile samples obtained after intravenous administration of sulphobromophthalein to rats showed the presence of at least twenty peaks of metabolites, of which thirteen were identified and seven quantified.

Photo-conductive hydro-fluorinated amorphous silicon carbide produced by using intermediate species SiF2

Abstract A new type of glow discharge hydro-fluorinated amorphous silicon carbide (a-SiC:F:H) is produced by mixing CH4 or CF4 with gas mixture of H2 and intermediate species SiF2. Boron and phosphorus are doped onto this a-SiC:F:H by mixing B2H6 and PH3 with the above mixture gas. It is found that the optical band gap of a-SiC:F:H can be increased up to 2.2eV without degradation of photo-conductive properties by increasing carbon content, and also that the conductivity of impurity doped a-SiC:F:H can be increased to a level higher than that of the similar hydrogenated amorphous silicon carbide (a-SiC:H) which is produced by CH4 and SiH4 gas mixture.

Impurity doping properties of hydrofluorinated amorphous silicon produced by intermediate species SiF2

Electrical and optical properties of boron‐ or phosphorus‐doped new hydrofluorinated amorphous silicon (a‐Si:F:H) are experimentally studied. This new a‐Si:F:H is produced by using intermediate species SiF2 and H2 gas mixture instead of using SiH4 gas or SiF4 and H2 gas mixture. It is found that the doping efficiency for boron or phosphorus in this a‐Si:F:H film is slightly better than that of conventional hydrogenated amorphous silicon (a‐Si:H), and also that the optical band gap of this a‐Si:F:H hardly changes for the increase of conductivity due to boron doping while that of a‐Si:H is apparently decreased.