Difference in the effectiveness of Ca2+ to evoke catecholamine secretion between adrenaline- and noradrenaline-containing cells of bovine adrenal medulla

Differential adrenaline (Ad) and noradrenaline (NA) secretions evoked by secretagogues were investigated using digitonin-permeabilized adrenal chromaffin cells, cultured adrenal chromaffin cells, and perfused adrenal glands of the ox. In digitonin-permeabilized cells, Ca2+ (0.8-160 microM) caused a concentration-dependent increase in catecholamine secretion, which was characterized by a predominance of NA over Ad secretion. Acetylcholine (10-1,000 microM), high K+ (14-56 mM), and bradykinin (0.1-1,000 nM) all were confirmed to induce the release of more NA than Ad at all concentrations used. There was no apparent difference in the ratios of NA/Ad between Ca(2+)-induced catecholamine secretion from digitonin-permeabilized cells and those induced by secretagogues from cultured cells. Qualitatively the same result was obtained in the secretory responses to acetylcholine and high K+ in perfused adrenal glands. These results indicate that the effectiveness of Ca2+ for catecholamine secretion is higher in the secretory apparatus of NA cells than in that of Ad cells of the bovine adrenal medulla. This may be one of the reasons why the secretagogues cause a predominance of NA secretion over Ad secretion in the bovine adrenal medulla.     

Simultaneous removal of nitrogen oxides and diesel soot particulates catalyzed by perovskite-type oxides

Perovskite-type oxides (ABO₃) catalyzed the simultaneous removal of NO_x and diesel soot particulates in the presence of oxygen, and were superior to transition metal simple oxides in the selectivity for NO_x reduction. Although the catalytic activity of perovskite-type oxides depended on both A-site and B-site cations, the substitution of potassium at A sites prominently promoted the oxidation of soot and the reduction of NO_x.     

Thermal and photo-induced surface damage in paratellurite

Long-term operation of TeO2 acousto-optical device is limited by the formation of surface damage caused by the He–Cd laser irradiation. Similar surface damage occurs during the heat treatment of the TeO2 crystal at 350°C. In this study, TeO2 specimens after various surface treatments have been observed by electron microscopy and X-ray photoelectron spectroscopy. The variation of the transmittance for mechanically polished specimens has been measured in situ during heat treatments. It was found that the thermal surface damage at 350°C was formed in the surface layer damaged by mechanical polishing. The mechanically damaged layer was amorphous and deficient in oxygen in the as-polished state. The electron microscopic observation revealed that the surface damage layer induced by heat treatments or by the ultraviolet light irradiation contained tellurium particles (20–40 nm) in diameter dispersed in the TeO2 matrix. On annealing the TeO2 specimen at 500°C in air, however, the particles disappeared because of the melting, evaporation and oxidation of tellurium which restores the transmittance of the crystal. Based on the results, combined with the observation of surface damage induced by the visible light irradiation, a possible mechanism of the surface damage formation has been briefly discussed. This revised version was published online in November 2006 with corrections to the Cover Date.     

Gain of chromosome 20 is a frequent aberration in liver metastasis of colorectal cancers

To investigate the characteristics of the numerical chromosome aberrations in liver metastasis of colorectal cancers, fluorescence in situ hybridization (FISH) for chromosomes 8, 18, 14/22, and 20 was performed in 18 specimens of primary regions and 18 of metastatic regions in liver metastasis of colorectal cancers compared with 15 of non-liver metastatic cancers. Among these numerical aberrations, the gain of chromosome 20, especially copy numbers exceeding three, was frequently observed in primary and metastatic cancers. Among these numerical aberrations, the gain of chromosome 20, especially copy numbers exceeding three, was frequently observed in primary and metastatic regions of liver metastasis groups compared with that of the non-liver metastasis group (P < 0.05). The incidences of gain of chromosome 20 in both regions of the liver metastasis group were higher than that of the non-liver metastasis group (P < 0.05). The gain of chromosome 20 is a frequent aberration in primary and metastatic regions in patients with liver metastatic colorectal cancers and may be available as a genetic marker for the diagnosis or prediction of liver metastasis.     

Room-temperature formation of low refractive index silicon oxide films using atmospheric-pressure plasma

This study aims to apply atmospheric-pressure (AP) plasma to the fabrication of single-layer anti-reflection (AR) coatings with porous silicon oxide. 150 MHz very high-frequency (VHF) excitation of AP plasma permits to enhance the chemical reactions both in the gas phase and on the film-growing surface, increasing deposition rate significantly. Silicon oxide films were prepared from silane (SiH4) and carbon dioxide (CO2) dual sources diluted with helium. The microstructure and refractive index of the films were studied using infrared absorption and ellipsometry as a function of VHF power density. It was shown that significant increase in deposition rate at room temperature prevented the formation of a dense SiO2 network, decreasing refractive index of the resulting film effectively. As a result, a porous silicon oxide film, which had the lowest refractive index of 1.24 at 632.8 nm, was obtained with a very high deposition rate of 235 nm/s. The reflectance and transmittance spectra showed that the low refractive index film functioned as a quarter-wave AR coating of a glass plate.     

Preparation of novel transparent glass–ceramics containing fluoride crystals

Transparent glass–ceramics containing YLiF₄ nano-crystals were synthesized by controlled heat-treatments of LiFYF₃Al₂O₃SiO₂ glass. The crystallite size estimated to be about 8 nm was much less than the wavelength of the visible light. The transmittance of the glass–ceramic with a thickness of 2 mm was more than 85% at 400 nm and as high as 95% in the infrared region. The fluorescence centered around 1000 nm was hardly observed from Er³⁺-doped precursor glass under 800 nm excitation, while the emission with the Stark spitting was clearly observed for the Er³⁺-doped glass–ceramic. The phonon sideband of the ⁷F₀ → ⁵D₂ excitation spectra of Eu³⁺ reveals that Eu³⁺ doped in precursor glass is in silicate network while Eu³⁺ doped in the glass–ceramic is in not only silicate framework but also fluoride framework. These results indicate that rare-earth ions such as Er³⁺ and Eu³⁺ could be successfully incorporated into YLiF₄ nano-crystals in the glass–ceramics.     

Relation between the Three-dimensional Flow Structure and Aerodynamic Sound Generated from Inclined Circular Cylinder

The major causes of the sound pressure level (SPL) variation due to the changes of the inclined angle of a circular cylinder and the aspect ratio (ratio of distance between endplates to cylinder diameter) were investigated. The velocity fluctuation of the wake and the surface pressure fluctuation of the cylinder were measured in a low noise wind tunnel to find the correlation length, coherent output power and Strouhal number. The results show that the changes of these values qualitatively correspond with the change of SPL. Flow visualization tests are performed to clarify the variation of wake in relation with inclined angle and aspect ratio. It is found that the spanwise structure of Karman's vortex street is broken down by the upward flows generated around the bottom endplate, and the degree of the interference between the upward flow and Karman's vortex street is smaller when the aspect ratio is larger.     

Photoluminescence and Absorption of a Zirconium Fluoride Glass and ZrF4

The glass containing reduced zirconium exhibits a photoemission band at 480 nm and an excitation band from 230 to 370 nm. Reduced zirconium tetrafluoride has broad absorption at 400 nm. Reduction of zirconium tetrafluoride occurs through fluorine or oxygen impurity elimination. When fluorine ion deficiency occurs, emission and excitation bands appear at 440 and 350 nm, respectively. When oxygen deficiency occurs, emission and excitation bands appear at 480 and 300 nm, respectively.     

Catalytic oxidation of nitrogen monoxide over La1−xCexCoO3 perovskites

This paper presents an investigation on the NO oxidation properties of perovskite oxides. La_1−xCe_xCoO₃ (x = 0, 0.05, 0.1, 0.2, 0.3, 0.4) perovskite-type oxides were synthesized through a citrate method and characterized by XRD, BET and XPS. The catalytic activities were enhanced significantly with Ce substitution, and achieved the best when x was 0.2, but decreased at higher x values. The performed characterizations reveal that the adsorbed oxygen on the surface plays an important role in the oxidation of NO into NO₂. The surface compounds after the co-adsorption of NO and O₂ at room temperature, were investigated by DRIFTS and TPD experiments. Three species: the bridging nitrate, the hyponitrites and the monodentate nitrate, were formed on the surface. The order of thermal stabilities was as follows: monodentate > hyponitrite > bridging. Among them, only the monodentate nitrate which decomposed at above 300 °C, would desorb NO₂ into the gas phase. When Ce was added, the temperature of monodentate nitrate desorption became low and the adsorption of the other two species decreased. This might be related to the oxidation state of Co on the surface. Analysis by synthesizing the characterization results and catalytic activity data shows that large amounts of adsorbed oxygen, small amount of inactive compounds on the surface and low NO₂ desorption temperature are favorable for the oxidation of NO.