Bonelike Apatite Formation Induced on Zirconia Gel in a Simulated Body Fluid and Its Modified Solutions

Formation of bonelike apatite on zirconia gel in a simulated body fluid (SBF) with ion concentrations almost equal to those in human blood plasma, in modified SBF solutions to have increased pH values, and modified SBF solutions to have increased concentrations of calcium and phosphate ions has been investigated. The zirconia gel forms apatite on its surface in SBF, indicating that Zr-OH groups, abundant on the gel, act as effective apatite nucleation centers. Apatite formation is accelerated by increases in pH and in the concentration of calcium and phosphate ions, which is explained by an increase in the ionic activity product of the apatite in the SBF. These results suggest that zirconia ceramics may exhibit a bone-bonding ability by forming an apatite layer on their surfaces in the living body when they are modified to have many Zr-OH groups on their surfaces.     

Kinetic study of support effect in the propane combustion over platinum catalyst

The support effect on the low-temperature propane combustion over platinum catalysts was investigated by kinetic study. The catalytic activity of supported platinum catalysts varied with the support material, and Pt/SiO₂–Al₂O₃ showed much higher activity than Pt/ZrO₂, as already reported. The reaction order for oxygen was negative and that for propane was positive. The reaction order for propane and oxygen also greatly depended on the support material: Pt/ZrO₂ gave anomalous reaction orders, i.e., –2.9 for oxygen and 3.4 for propane. Further, oxidized Pt/ZrO₂ showed a long-term change of the catalytic activity with time-on-stream, compared with oxidized Pt/SiO₂–Al₂O₃. From these results, it was concluded that high catalytic activity of platinum on acidic support is attributed to high ability to maintain the metallic state of platinum with high oxidation-resistance and high reducibility of platinum oxide.     

Effect of low segregation coefficient on Ga‐doped multicrystalline silicon solar cell performance

High‐quality Ga‐doped ingots are grown in different casting furnaces at optimized growth parameters; 3·5 kg ingots exhibit normal distribution of diffusion lengths along their height with very high diffusion lengths at the center of the ingot. Effective lifetimes as high as 1·1 ms are realized in 10 Ω cm Ga‐doped wafers after proper P‐diffusion and hydrogen passivation. Average effective lifetimes above 400 µs are also realized after P‐diffusion and hydrogen passivation for Ga‐doped wafers cut from 75 kg ingot where the response to P‐diffusion and hydrogen passivation is pronounced. High effective lifetimes are realized over the whole ingot with minimum values of 20 µs at the top of the ingot, indicating the possible use of about 85% of the ingot for solar cell production. Conversion efficiencies above 15·5% were realized in utilizing more than 80% of the ingot. High efficiencies of about 16% were realized in wafers with resistivities higher than 5 Ω cm p ‐type multicrystalline silicon wafers. Copyright © 2005 John Wiley & Sons, Ltd.     

Homogenized model of environmental barrier coatings for evaluation of energy release rate

For efficient calculation of energy release rate (ERR) for interface cracks in environmental barrier coatings (EBCs) with a columnar layer, we propose a simple and versatile homogenization method of the columnar layer. The columnar layer consisting of a number of fine columns is modeled as an anisotropic homogenized layer whose elastic properties are isotropic in the plane perpendicular to the layer thickness direction. The homogenization was achieved by a finite element method (FEM) analysis for a single columnar model to obtain elastic parameters that characterize the homogenized layer. For validation of the homogenization method, we conduct an FEM analysis for a typical EBC structure and obtain the ERRs of an interface crack with various crack length and columnar size. We demonstrate that the homogenization method provides estimation of ERR with a good accuracy on the safer side, which is advantageous for EBC structure design. In addition, the method can reduce the calculation time by more than 50%. From these results, we conclude that the proposed homogenization method can be applied generally for estimation of ERR in EBCs with a columnar layer.     

光催化剂型抗污染装置

空调器的冷却塔、水的净化槽、过滤器等中，在水中的光接收环境中可以防止藻类的产生。为了达到这种目的，一个抗污染物体（2）浸渍在水中（1），表面接收光，作为第一个传导部分。表面上提供光催化层（3），如抗污染物表面。第二个传导部分接电，通过外电路（4）与传导抗污染物（2）结合作为一个反向电极（5），并被置于水中（1）。     

Sphingomyelin Deacylase,the Enzyme Involved in the Pathogenesis of Atopic Dermatitis,Is Identical to the β-Subunit of Acid Ceramidase

A ceramide deficiency in the stratum corneum (SC) is an essential etiologic factor for the dry and barrier-disrupted skin of patients with atopic dermatitis (AD). Previously, we reported that sphingomyelin (SM) deacylase, which hydrolyzes SM and glucosylceramide at the acyl site to yield their lysoforms sphingosylphosphorylcholine (SPC) and glucosylsphingosine, respectively, instead of ceramide and/or acylceramide, is over-expressed in AD skin and results in a ceramide deficiency. Although the enzymatic properties of SM deacylase have been clarified, the enzyme itself remains unidentified. In this study, we purified and characterized SM deacylase from rat skin. The activities of SM deacylase and acid ceramidase (aCDase) were measured using SM and ceramide as substrates by tandem mass spectrometry by monitoring the production of SPC and sphingosine, respectively. Levels of SM deacylase activity from various rat organs were higher in the order of skin > lung > heart. By successive chromatography using Phenyl-5PW, Rotofor, SP-Sepharose, Superdex 200 and Shodex RP18-415, SM deacylase was purified to homogeneity with a single band of an apparent molecular mass of 43 kDa with an enrichment of > 14,000-fold. Analysis by MALDI-TOF MS/MS using a protein spot with SM deacylase activity separated by 2D-SDS-PAGE allowed its amino acid sequence to be determined and identified as the β-subunit of aCDase, which consists of α- and β-subunits linked by amino bonds and a single S-S bond. Western blotting of samples treated with 2-mercaptoethanol revealed that, whereas recombinant human aCDase was recognized by antibodies to the α-subunit at ~56 kDa and ~13 kDa and the β-subunit at ~43 kDa, the purified SM deacylase was detectable only by the antibody to the β-subunit at ~43 kDa. Breaking the S-S bond of recombinant human aCDase with dithiothreitol elicited the activity of SM deacylase with ~40 kDa upon gel chromatography. These results provide new insights into the essential role of SM deacylase expressed as an aCDase-degrading β-subunit that evokes the ceramide deficiency in AD skin.     

Preparation of modified polybutene‐1 by oxidation and limonene radical grafting using an Nd2O3‐assisted radical initiator system and its characterization

Free radical graft polymerization has been used as a modification method to incorporate functional groups into polyolefins using a melt‐mixing process. In this work, modification of polybutene‐1 (PB) was performed by limonene radical graft polymerization using the Nd₂O₃/dicumyl peroxide (DCP) radical initiator system with various mixing ratios in air. The effects of the modification on the crystallization and tensile behavior were studied in detail. The modified PB samples had ketone and limonene groups. The contents of both the ketone and the limonene groups were highest in the modified PB prepared using Nd₂O₃/DCP (2/0.2 wt%/PB), and a conjugated diene group was found to be produced by a side‐reaction. Excess Nd₂O₃ lowered the limonene graft content in the modified PB. The rate of crystal phase transition (II → I) decreased with an increase of limonene content. The presence of a small amount of the ketone group increased the rate, and the modified PB having a small ketone content exhibited more ductility due to its higher crystal phase transition rate. It was found that there was an optimum mixing ratio of the Nd₂O₃/DCP initiator system for the modification. The ketone and the limonene groups affected the rate of the crystal phase transition and the tensile properties of the modified PB. Copyright © 2010 Society of Chemical Industry     

State criterion of wind turbine generator operation using tower shadow effect (Part 2)

In order to obtain wind energy effectively, the pole‐change‐type induction generators are used as the wind turbine generators. Otherwise, the pole‐change‐type induction generator causes the voltage dips at pole changing time. To maintain the power quality, it is important to know the state change of the generator operation. Therefore, the authors have studied a state criterion of generator using the tower shadow effect, which is the active power oscillation caused by a rotation torque drop when the tower and the turbine blade overlap each other. In this paper, an improved identification method of oscillation frequency, which is the criterion of wind turbine generator operation, is proposed. The proposed method is applied to measured data and good results are obtained. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 162(1): 25–31, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20395     

Self‐organization of amphiphilic poly[2‐(methacryloyloxy)ethyl phosphorylcholine] carrying tocopheryl moieties as terminal groups

Poly[2‐(methacryloyloxy)ethyl phosphorylcholine](PMPC) with one pendant tocopheryl moiety at the polymer terminus (PMPC‐Toco) was prepared by the radical polymerization of 2‐(methacryloyloxy)ethyl phosphorylcholine (MPC) initiated with 4,4′‐azobis[(3‐tocopheryl)‐4‐cyanopentanoate] in the presence of 2‐mercaptoethanol as a chain transfer reagent. The self‐organization of PMPC‐Toco was analyzed with fluorescence and ¹H‐NMR measurements. The critical micelle concentrations of PMPC‐Toco with [η] = 0.25, 0.13, 0.10, and 0.05 dL g^?1 were found to be 200, 100, 100, and 90 mg L^?1, respectively. The blood compatibility of PMPC‐Toco was evaluated from the Michaelis constant (K_m) for the enzymatic reaction of thrombin and a synthetic substrate, S‐2238, in the presence of PMPC‐Toco. The K_m values were 0.21, 0.23, 0.36, and 0.21 for PMPC‐Toco‐1, 2, 3, and PMPC ([η] = 0.56 dL g^?1), respectively. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009