Preparation and sintering of narrow-sized Al2O3-TiO2 composite powders

Narrow size distribution Al₂O₃-TiO₂ composite powders containing nominally 10 to 60 mol % TiO₂ were prepared by the stepwise hydrolysis of titanium alkoxide in an Al₂O₃ dispersion. Particle size was controlled by selecting the particle size of the starting Al₂O₃ powder. The TiO₂ content was determined by the amount of alkoxide hydrolysed. Composite powder compacts were prepared by filter casting or centrifugal casting the composite powder dispersions. All compacts had similar shrinkage behaviour during sintering. When fired above 1300° C, the compacts containing less than 50 mol % TiO₂ became Al₂TiO₅-Al₂O₃ composite bodies with high densities, the compact containing 50 mol % TiO₂ became an Al₂TiO₅ body with domain structure, and the compact containing 60 mol % TiO₂ formed a TiO₂-Al₂TiO₅ composite structure. When these composite bodies were annealed below 1300° C, they showed different decomposition behaviour and microstructures.     

Analysis and design of semileaky-type thin-film optical waveguide isolator

This paper describes an optical waveguide isolator that utilizes the unidirectional guided-radiation mode coupling in a magnetooptic/anisotropic slab guide. The basic structure is the semileaky-type waveguide that has been previously used as a polarization mode filter. Specific features of the proposed device are its compact one-section form resulting from the inherent polarization-discrimination property and the relaxed dimensional tolerance due to the automatic phase-matching of coupled modes. Design data and a related discussion are given for the example of LiNbO3/YIG/GGG layered structure operating in the 1.15-μm-wavelength region.     

Synthesis of continuous silicon carbide fibre

The structure of polycarbosilane is represented by three structural elements, but their quantification is difficult. Polycarbosilanes were synthesized by three methods and the respective molecular structures were examined by measurements of the molecular weight and the intrinsic viscosity, infrared, ultraviolet,¹H-,¹³C- and²⁹Si-NMR spectral measurements, and chemical analysis. The three structural elements (SiC₄, SiC₃H, SiC _x Si_4–x ) in the polycarbosilane molecule were determined quantitatively. By the comparison between¹H-NMR spectral data and calculation assuming a linear chain structure, the number of linkages in the unit consisting of ten silicon atoms was estimated to be 3 to 4. This result is in agreement with the result from the intrinsic viscosity; it was found that the shape of the polycarbosilane molecule is planar.     

Susceptibility of calcium-deficient hydroxyapatite-collagen composite to irradiation

The ESR spectrum of calcium-deficient hydroxyapatite (DAp) has the peaks assigned to the hyperfine structure of dangling H+ (hyperfine coupling constant = 50.8 mT, I = 1/2) due to the HPO(4)2- ion which captured the hole released by X ray irradiation. This ESR peak intensity in DAp with collagen (c-DAp) decreased in an increase in the amount of collagen added into Ca(H2PO4)2H2O (MCP) electrolytic solution, because dangling H+ of HPO(4)2- binds to the carboxyl group of collagen due to the hydrogen bond. The ESR signal intensities at near g = 2 in DAp, c-DAp, and stoichiometric hydroxyapatite (HAp) after X ray irradiation, were proportional to the absorbed dose in the range from 6 to 380 Gy. These ESR signal intensities decreased when the X ray-irradiated DAp, c-DAp, and HAp was suspended in the simulated body fluid. This fact suggests that the surface layer contained high density of ESR active species in DAp, c-DAp, and HAp dissolved in the simulated body fluid. Therefore, with the dosemeter utilising such biomaterials as tooth and bone, sufficient care must be paid to the effect of body fluid.     

Light diffusion model for determination of optical properties of rectangular parallelepiped highly scattering media

A method to determine the absorption and reduced scattering coefficients of rectangular parallelepiped highly scattering media from frequency-domain photon migration measurements is presented. An analytical model for photon diffusion propagation in the rectangular parallelepiped media is established using the method of images and extrapolated boundary conditions. This present technique has simplicity, accuracy, and rapid computability as compared with the Monte Carlo or finite element methods. The theoretical predictions are verified with experimental measurements using a white polyacetal resin, and the errors introduced by using the slab geometry for the optical property determination are identified.     

Lymphatic Absorption and Deposition of Various Plant Sterols in Stroke-Prone Spontaneously Hypertensive Rats,a Strain Having a Mutation in ATP binding cassette transporter G5

ATP binding cassette transporter G5 (ABCG5) and ATP binding cassette transporter G8 (ABCG8) have been suggested to transport absorbed plant sterols and cholesterol from enterocytes to the intestinal lumen and from hepatocytes to bile. It has been thought that mutations of ABCG5 or ABCG8 cause the deposition of plant sterols in the body. In the present study, lymphatic absorption of various plant sterols and their deposition in various tissues was investigated in stroke-prone spontaneously hypertensive rats (SHRSP), having a mutation in Abcg5 and depositing plant sterols in the body. The order of lymphatic 24-h recovery of plant sterols was as follows: campesterol > sitosterol > brassicasterol > stigmasterol = sitostanol. When SHRSP were fed a diet containing one of the plant sterols, the depositions of campesterol and sitosterol were comparatively higher than those of brassicasterol, stigmasterol and sitostanol. Highly positive correlations were obtained between lymphatic recovery of plant sterols and their levels in plasma, liver, adipose tissue and heart. The tendency of differential absorption of plant sterols to the lymph in SHRSP was similar to that in normal Wistar rats previously reported by us (Hamada et al. Lipids 41:551–556, 2006). These observations suggest that differential absorption of various plant sterols is kept in SHRSP in spite of a mutation in Abcg5.     

A novel extraction method of fetal electrocardiogram from the composite abdominal signal

In contrast to the ultrasonic measurement of fetal heart motion, the fetal electrocardiogram (ECG) provides clinically significant information concerning the electrophysiological state of a fetus. In this paper, a novel method for extracting the fetal ECG from abdominal composite signals is proposed. This method consists of the cancellation of the mother's ECG and blind source separation with the reference signal (BSSR). The cancellation of the mother's ECG component was performed by subtracting the linear combination of mutually orthogonal projections of the heart vector. The BSSR is a fixed-point algorithm, the Lagrange function of which includes the higher order cross-correlation between the extracted signal and the reference signal as the cost term rather than a constraint. This realizes the convexity of the Lagrange function in a simple form, which guarantees the convergence of the algorithm. By practical application, the proposed method has been shown to be able to extract the P and T waves in addition to the R wave. The reliability and accuracy of the proposed method was confirmed by comparing the extracted signals with the directly recorded ECG at the second stage of labor. The gestational age-dependency of the physiological parameters of the extracted fetal ECG also coincided well with that of the magnetocardiogram, which proves the clinical applicability of the proposed method.     

A psychometric analysis of the Positive and Negative Affect Schedule for Children–Parent Version in a school sample.

The current study was the 1st to examine the psychometric properties of the Positive and Negative Affect Schedule for Children–Parent Version (PANAS-C-P) using a large school-based sample of children and adolescents ages 8 to 18 (N = 606). Confirmatory factor analysis supported a 2-factor (correlated) model of positive affect (PA) and negative affect (NA). The PANAS-C-P scale scores also demonstrated acceptable internal consistency and convergent and divergent validity. The PANAS-C-P PA and NA scale scores also related to measures of anxiety and depression in a manner consistent with the tripartite model. Scale means and standard deviations were reported by grade and sex to provide normative data for the PANAS-C-P scales. Results from the present study provide initial support for the PANAS-C-P as a parent-reported perspective of youth PA and NA among school-based youths. (PsycINFO Database Record (c) 2011 APA, all rights reserved)