Microporous polypropylene fibers containing poly(methylsilsesquioxane) filler

Microporous polypropylene fibers were prepared by stretching polypropylene fibers containing poly(methylsilsesquioxane) filler. The properties of the resultant fibers are controllable by adjusting the filler content and stretching degree. The resultant fibers have a fine texture of polypropylene fibrils, in which the filler particles are dispersed. Some properties were investigated: tensile strength, elongation, Young's modulus, porosity, pore size, and specific surface area. © 1996 John Wiley & Sons, Inc.     

Network copolyesters from benzenepolycarboxylic acids and 1,6-hexanediol

Network copolyesters were prepared from trimesic (Y), pyromellitic (X) or mellitic (Y_H) acids and 1,6-hexanediol (6G). Prepolymers prepared by meltpolycondensation were cast from dimethylformamide solution and postpolymerized at 260°C for 6h to form a network. The resultant films were transparent, flexible and insoluble in any organic solvents. Degree of reaction estimated from the infrared absorbance of ester and methylene groups was almost the same for all films, 94–96%. X-ray diffraction intensity curves and densities showed that the ordering of networks was decreased by the copolymerization, which was remarkable for 6G–X/Y_H copolymer films and was consistent with the higher decreases of heat-distortion temperature for these copolymer films. The copolymerization also caused decrease of thermal stability, tensile properties and alkali resistance and increase of dye absorption.     

Influence of Tip Clearance on Blade Vibration of Vaneless Radial Turbine

With the increasing demand of turbochargers with high performance and low turbo lag, high cycle fatigue (HCF) of radial turbine blades has become the most commo...     

Effect of Talc Size on Surface Roughness and Glossiness of Polypropylene Injection Molding Application to Automotive Plastics

Talc-containing polypropylene (PP) resin is extensively employed in automobiles. Herein, considering the microstructure transfer process in injection molding, the effect of the talc's dispersibility and particle size on this process and its impact on the gloss level of the product were investigated. Results show that a fine unevenness of about several micrometers was self-formed by the shrinkage of PP in nontransferred areas due to the blending of talc. Additionally, the amount of self-formed unevenness tended with an increase in the average particle size of talc. Furthermore, due to PP shrinkage and different densities of talc, it was observed that a fine tiger-stripe pattern was self-formed using special molds with modified microstructure. This self-formed fine unevenness changes the gloss level owing to the diffused light reflection effect. This study proposes controlling this change by controlling the average particle size of talc and structure of the mold. POLYM. ENG. SCI., 60:132–139, 2020. © 2019 Society of Plastics Engineers     

Developmental ability of cloned embryos from neural stem cells

The success rate is generally higher when cloning mice from embryonic stem (ES) cell nuclei than from somatic cell nuclei, suggesting that the embryonic nature or the undifferentiated state of the donor cell increases cloning efficiency. We assessed the developmental ability of cloned embryos derived from cultured neural stem cell (NSC) nuclei and compared the success rate with that of embryos cloned from other donor cells such as differentiated NSCs, cumulus cells, Sertoli cells and ES cells in the mouse. The transfer of two-cell cloned embryos derived from cultured NSC nuclei into surrogate mothers produced five live cloned mice. However, the success rate (0.5%) was higher in embryos cloned from cultured NSC nuclei than from differentiated NSCs (0%), but lower than that obtained by cloning mice from other cell nuclei (2.2-3.5%). Although the in vitro developmental potential to the two-cell stage of the cloned embryos derived from NSC nuclei (73%) was similar to that of the cloned embryos derived from other somatic cell nuclei (e.g., 85% in Sertoli cells and 75% in cumulus cells), the developmental rate to the morula-blastocyst stage was only 7%. This rate is remarkably lower than that produced from other somatic cells (e.g., 50% in Sertoli cells and 54% in cumulus cells). These results indicate that the undifferentiated state of neural cells does not enhance the cloning efficiency in mice and that the arrest point for in vitro development of cloned embryos depends on the donor cell type.     

Evaluation of drug toxicity with hepatocytes cultured in a micro-space cell culture system

A micro-space cell culture system was recently developed in which cells such as hepatocytes can be cultured and formed into a multicellular three-dimensional (3D) architecture. In this study, we assessed the performance of HepG2 cells cultured in this micro-space cell culture system in a drug toxicity test, and evaluated the effects of micro-space culture on their hepatocyte-specific functions. The micro-space cell culture facilitated the formation of 3D HepG2 cell architecture. HepG2 cells cultured in a micro-space culture plate exhibited increased albumin secretion and enhanced mRNA expression levels of cytochrome P450 (CYP) enzyme compared to those cultured in a monolayer culture. When the cells were exposed to acetaminophen, a hepatotoxic drug, the damage to the HepG2 cells grown in micro-space culture was greater than the damage to the HepG2 cells grown in monolayer culture. In addition, human primary hepatocytes grown in micro-space culture also exhibited increased albumin secretion, enhanced CYP mRNA expression levels and increased sensitivity to acetaminophen compared to those grown in monolayer culture. These results suggest that this micro-space culture method enhances the hepatocyte-specific functions of hepatocytes, including drug-metabolizing enzyme activities, making hepatocytes grown in the micro-space culture system a useful tool for evaluating drug toxicity in vitro.     

Effects of highly hydrogenated soybean oil and cholesterol on plasma,liver cholesterol,and fecal steroids in rats

We investigated the relationship between dietary highly hydrogenated soybean oil (HSO) and cholesterol transport in rats. In the first study, to examine the effects of cholesterol transport of different concentrations of HSO in dietary oil, rats were given one of the three diets containing 0, 25, or 50% HSO in dietary oil with cholesterol (5 g/kg diet) or a diet without HSO and cholesterol for 22 d. Feeding the high concentration of HSO prevented the increase in plasma total cholesterol, hepatic total lipids, and cholesterol and the decrease in high-density lipoprotein-cholesterol, which were caused by dietary cholesterol. Moreover, HSO increased the fecal excretion, fecal lipids, and steroids in a dose-dependent manner. In the second study, to examine the effects on cholesterol transport of redistribution of stearic acid in the triacylglycerol species contained in HSO, rats were given one of the six diets containing HSO (distearoylmonoacylglycerol and tristearoylglycerol)-rich, monostearoylglycerol-rich, or palmitic acid-rich oil with/without cholesterol (5 g/kg diet), for 30 d. Whereas the accumulation of cholesterol in the body was reduced, cholesterol excretion was enhanced effectively in rats given the HSO-rich diet compared with rats given the monostearoylglycerol-rich diet. These results suggested that not only the high concentration of stearic acid but also its uneven distribution in HSO-triacylglycerol contributed to the reduction in intestinal cholesterol absorption in rats.     

Modifying ability of Ql-free coal-tar pitch to develop optical anisotropy in co-carbonizations

Carbonization properties of a Ql-free coal-tar pitch (CTP-ASM) prepared by selective precipitation were studied to evaluate it as a source for needle-coke. Its modifying ability for production of needlecoke in co-carbonizations with principal carbonizing substances which gave cokes of mozaic texture in single carbonizations was estimated by changing mixing ratios. The shape and size of the anisotropic optical texture in the co-carbonized coke were measured by point counting. CTP-ASM and Ashland A240, of eight additives, had the highest modifying ability in the co-carbonizations with Khafji vacuum residue. Both contained ca. 6% benzene-insolubles (Bl), and had f_a values of ≈0.9. Other additives of either lower or higher Bl or f_a showed less modifying ability. The modifying susceptibility of principal carbonizing substances varies with their structure and properties. Based on a systematic investigation of co-carbonizations the compatibility between a principal carbonizing substance and an additive is discussed from a viewpoint of their structural parameters.     

Evaluation of the pseudocapacitance in RuO2 with a RuO2/GC thin film electrode

The pseudocapacitance of nanocrystalline RuO₂ with BET surface area of 42 m² g⁻¹ was evaluated using a RuO₂ modified Glassy Carbon (RuO₂/GC) thin film electrode. The charge storage behavior of the RuO₂/GC thin film electrode was studied from fast to slow scan cyclic voltammetry between various potential windows. The utilization of the thin film electrode method for nanocrystalline RuO₂ with known specific surface area allowed a semi-quantitative understanding of the electric double-layer capacitance (C_dl), adsorption related charge (C_ad), and the irreversible redox related charge (C_irr) per unit mass and surface area of RuO₂. Comparison of the cyclic voltammograms between different voltage windows revealed that the contribution from C_irr is especially dominant below 0.4 V (versus RHE) at slow scan rates.     

Computer simulation of CAICISS spectra of clean Cu(1 0 0) surface and Cu(1 0 0) surface by Pt deposition

The clean Cu(1 0 0) surface and Pt/Cu(1 0 0) surface by Pt deposition at room temperature have been investigated using the computer simulation of coaxial impact-collision ion scattering spectroscopy (CAICISS). The computer simulations employing the ACOCT program code, which treats the atomic collisions three-dimensionally and is based on the binary collision approximation (BCA), were carried out for the case of 3 keV He⁺ ions incident along the 〈1 0 0〉 and 〈1 1 0〉 azimuths of the clean Cu(1 0 0) and Pt/Cu(1 0 0) surfaces. The comparisons between ACOCT results and experimental CAICISS data show that the experimental results on the clean Cu(1 0 0) surface are relatively well reproduced by the ACOCT simulations including the inward relaxation of 1.2% in the first interlayer spacing and the outward relaxation of 1.6% in the second interlayer spacing, and that the ACOCT simulations for the Pt deposition with coverages of 2.35 ML and 2.75 ML on the Cu(1 0 0) surface appear the concentrations of 0.24 ML of Pt sitting 2.3 Å and 0.25 ML of Pt sitting 2.5 Å above the outermost atomic layer, respectively.