Enhancement by streptozotocin of O−2 radical generation by the xanthine oxidase system of pancreatic β-cells

AbstractSpin-trapping techniques and electron spin resonance (ESR) spectroscopy were used to study the relationship between the effect of streptozotocin (STZ) on pancreatic β-cells and free radical formation by these cells. Results showed that STZ enhanced generation of the DMPO-OH radical adduct, which is a degradation product of the superoxide anion (O−2) in the presence of cellular components, in a hypoxanthine-xanthine oxidase (XOD) system with a homogenate of β-cells. This enhancing effect was also observed in a system without cellular components; STZ increased the signal height due to the O−2 radical in a concentration-dependent manner and caused a maximum of 150% enhancement at a concentration of 1.5 mM. Thus, STZ seemed to enhance the generation of the O−2 radical in the XOD system, probably by some mechanism of its interaction with XOD. Pancreatic β-cells exhibited a high XOD activity and a very low superoxide dismutase activity. Therefore, the present result supports the possibility that the cytotoxic effect of STZ is closely related to free radical generation in pancreatic β-cells

Light Figure Phenomena Revealed and Crystal Faces Developed by Chemical Etching in Silicon Crystal

The light-figure phenomenon of silicon single crystals etched with various chemical reagents has been studied in order to find out the light figures or the etching conditions appropriate for the orientation determination and to obtain information regarding crystal faces developed by etching. The etching with aqueous solutions of KOH and of NaOH, boiled or heated at 100° or 70℃, produce distinct {100}, {110}, and {111} light figures, while any other oxidizable reagent reveals only indistinct light figures or no light figure at all. It has been found that, for the orientation works, the etching with saturated aqueous solutions of KOH and of NaOH, heated over some 100℃ are most suitable in view of the shortness of the required etching time ( and zones, the {111} and {100} faces being commonly developed

CU(OH)2 ノ DTA ニヨル ダッスイ カテイ

The thermal dehydration of Cu(OH)_2 has been studied by many investigators. The reported DTA curves were not in good agreement and the dehydration process was not investigated in detail. In this study the thermal dehydration process of Cu(OH)_2 under CO_2,N_2,Air and reduced pressure has been investigated in ditail by means of DTA, TG, DSC, X-ray and surface area measurement. The heat of the dehydration and the activation energy on the dehydration of Cu(OH)_2 were calculated by various method and these values were compared each other. The dehydration temperature of Cu(OH)_2 was 157℃ under atmosphere N_2,760mmHg. The DTA of Cu(OH)_2 has not been studied under N_2,CO_2 and reduced pressure. The DTA of Cu(OH)_2 under various pressure (760mmHg→5mmHg) was measured and the dehydration temperature was gradually shifted to lower temperature with decreasing pressure. A new exothermic peak appeared at 230℃ after the endothermic peak. This exothermic peak has not been reported. This peak hight became to maximum under the pressure of 460mmHg and became smaller with decreasing pressure and then disappeared under the pressure of 5mmHg. This peak was considered to be due to the crystalization of CuO on the result of X-ray analysis. The activation energy on the dehydration of Cu(OH)_2 were calculated 11.1 kcal/mole by using the DTA method, 9. 9 kcal/mole by the TG method and the heat of the dehydration of Cu(OH)_2 were calculated 14.8 kcal/mole by the DTA method, 11.4 kcal/mole by the DSC method. The specific surface area and the particle size of Cu(OH)_2 mesuared by using the BET technique were 34m^2/g, 250Å respectively. The specific surface area was increased with proceeding the decomposition reaction. This specific surface area became to maximum value, 103m^2/g at decomposition rate 90% and decreased to 66 m^2/g at decomposition rate, 100%. The particle size was decreased with the proceeding decomposition rate and this particle size became to minimum value, 46 Å at decomposition rate, 90%

CO2 N2 オヨビ クウキ フンイキカ ニオケル CD(OH)2 ノ DTA キョクセン

The so far obtained reports have shown that three endothermic peaks at 200～500℃ or the one endothermic peak at 216℃ appeared on the DTA curve of Cd(CH)_2 under the atmosphere air. In this report the thermal decomposition process of Cd(OH)_2 was studied by means of DTA and TG under atmosphere CO_2,N_2 and air. The DTA and TG curves under the atmosphere CO_2,N_2 have not been reported. The one exothermic peak and two endothermic peaks appeared on the DTA curve under the atmosphere CO_2. This exothermic peak was considered to be due to the formation of CdCO_3 and also the two endothermic peaks due to the decomposition of Cd(OH)_2 and CdCO_3. The formation reaction of CdCO_3 occured during the decomposition of Cd(OH)_2,and then the decomposition of CdCO_3 took place when the decomposition of Cd(OH)_2 was completed. It was considered from the results obtained that the following reactions occured during the thermal decomposition of Cd(OH)_2 under atmosphere CO_2 : endothermic peak at 265℃ Cd(OH)_2→CdO+H_2O exothermic peak at 240～340℃ CdO+CO_2→CdCO_3 endothermic peak at 468℃ CdCO_3→CdO+CO_

The Far-Infrared Surveyor (FIS) for AKARI

The Far-Infrared Surveyor (FIS) is one of two focal plane instruments on the AKARI satellite. FIS has four photometric bands at 65, 90, 140, and 160 um, and uses two kinds of array detectors. The FIS arrays and optics are designed to sweep the sky with high spatial resolution and redundancy. The actual scan width is more than eight arcmin, and the pixel pitch is matches the diffraction limit of the telescope. Derived point spread functions (PSFs) from observations of asteroids are similar to the optical model. Significant excesses, however, are clearly seen around tails of the PSFs, whose contributions are about 30% of the total power. All FIS functions are operating well in orbit, and its performance meets the laboratory characterizations, except for the two longer wavelength bands, which are not performing as well as characterized. Furthermore, the FIS has a spectroscopic capability using a Fourier transform spectrometer (FTS). Because the FTS takes advantage of the optics and detectors of the photometer, it can simultaneously make a spectral map. This paper summarizes the in-flight technical and operational performance of the FIS.Comment: 23 pages, 10 figures, and 2 tables. Accepted for publication in the AKARI special issue of the Publications of the Astronomical Society of Japa

Goitrogenic Action of Manganese on Female Mouse Thyroid through Three Generations : Endocrinology

Volume: 5Start Page: 1043End Page: 104