Electro-mechanical coupling in ionic gels

An ionic-polymer–metal-composite film shows electro-mechanical coupling. When the film is bent, electric current is induced. Measurement of the induced current indicates that the current depends on the speed of bending, but the total amount of the charge transferred across the film is independent of the speed, and depends only on the magnitude of the bending. The result indicates that in addition to previously proposed dynamical coupling effect, there is a static electro-mechanical coupling effect. Mathematical model is proposed to describe this phenomena.     

Round robin on indentation fracture resistance of silicon carbide ceramics by using a powerful optical microscope

Reproducibility of indentation fracture resistance, K_IFR of silicon carbides sintered with B and C was evaluated by a round robin with ten laboratories. When the crack length was measured with an optical microscope at a low magnification of ～100×, K_IFR varied widely from 3.43 to 4.20 MPa m^1/2, whereas those obtained by a powerful microscopy with both an objective lens of 40× and a traveling stage exhibited a consistent value of 3.20±0.12 MPa m^1/2. The wide scatter of K_IFR for the former measurements was attributed mainly to the variation in misreading of the crack length. It was revealed that the high resolving power of the objective lens of 40× enabled to find exact crack tips easily, which resulted in the good matching of K_IFR between laboratories for the latter case. It was suggested that the observation of indentations with powerful optics was effective for improving the reproducibility of the IF method.     

Role of adsorbed iodine into poly(vinyl alcohol) films drawn in KI/I2 solution

We have investigated the microstructure of the poly(vinyl alcohol) (PVA) films using small- and wide-angle X-ray scattering (SAXS and WAXS, respectively) techniques. The samples were uniaxially drawn in water or KI/I₂ aqueous solution and then dried in an air-oven at 333 K for 1 h prior to SAXS and WAXS measurements. It was found that for the films drawn in KI/I₂ solution PVA chains in the microfibrillar structure are more extended upon the film drawing compared to the case of the films drawn in pure water, which is resulted from the correlation function analysis on the SAXS data. Adsorbed iodines into the film were anticipated to act as junction points between the microfibrils via the formation of the PVA-iodine complexes.     

Effect of rapid sample cooling on efficiency of multiple impurity-atom doping

Shallow and efficient doping of wide band-gap semiconductors has remained one of yet unresolved problems to date. A possible solution to this problem is doping with complexes of a few impurity atoms at a quasi-equilibrium state, which is introduced by controlled cooling of a sample after doping. In this work, (1) we first define a global and quasi-equilibria of our interest based on a simple thermodynamic model for a doped crystal, and then (2) we discuss how the cooling rate affects the probability of impurity-complex formation at a quasi-equilibrium as defined. Our main message is that one should design impurity complexes as small in size as possible which have as large a binding energy as possible. This is a required condition for complex designs when it is difficult to tune the cooling rate.     

Long Crack R-Curve of Aligned Porous Silicon Nitride

Long crack R -curve of a porous Si₃N₄ with aligned fibrous grains was investigated, using a chevron-notched beam technique. A crack was constrained to propagate normal to the grain alignment. The crack growth resistance of aligned porous Si₃N₄ was much larger compared with that of dense Si₃N₄ ceramics. Microstructure observations showed that pullouts of fibrous grains in aligned porous Si₃N₄ markedly increased during crack propagation relative to those of dense Si₃N₄, due to the existence of pores. The efficient grain pullouts in porous Si₃N₄ increased the bridging stress at the crack wake.     

New Natural Pigment Fraction Isolated from Saw Palmetto: Potential for Adjuvant Therapy of Hepatocellular Carcinoma

For the first time, we discovered a small proportion of aqueous fraction from Saw Palmetto apart from the fatty acid-rich fraction exhibited pharmacological activity. Therefore, this study aims to explore the anti-tumor potential of red pigmented aqueous fraction of Saw Palmetto, NYG on human hepatocellular carcinoma and its possible targets. Subcutaneous xenograft and orthotopic implantation models of HCC were used to evaluate the tumor inhibitory effect of NYG. Human hepatocellular carcinoma (HCC) cell lines and human umbilical vein endothelial cells (HUVEC) were used as in vitro model. The mRNA expression was conducted by qPCR. Protein expression was monitored by immunoblotting and immunohistochemistry. Cell migration and blood vessel formation were determined by chamber assay and tube formation assay, respectively. Significant tumor inhibition of NYG in dose-dependent manner was observed on subcutaneous xenograft and orthotopic HCC model. NYG has no direct action on cell viability or VEGF secretion of HCC cells. However, NYG reduced in vitro migration and vessel formation activities of HUVEC cells, as well as in vivo intratumoral neovascularization. NYG attenuated extracellular signal-regulated kinases (ERK) activation in endothelial cells, which may be associated with the suppression of migration and tube formation of HUVEC. NYG suppressed tumor expansion of HCC via inhibiting neovascularization, and may be potential adjuvant treatment for HCC.     

Effect of medium-chain fatty acid positional distribution in dietary triacylglycerol on lymphatic lipid transport and chylomicron composition in rats

The present study was carried out to examine if the positional distribution of medium-chain fatty acid (MCF) in dietary synthetic fat influences lymphatic transport of dietary fat and the chemical composition of chylomicrons in rats with permanent cannulation of thoracic duct. Four types of synthetic triacylglycerol were prepared: (i) sn-1(3) MCF-sn 2 linoleic acid, (ii) interesterified sn-1(3) MCF-sn 2 linoleic acid, (iii) sn-2 MCF-sn-1(3) linoleic acid, and (iv) interesterified sn-2 MCF-sn-1(3) linoleic acid. A purified diet composed of equal amounts of the synthetic fat and cocoa butter was given to rats with permanent lymph duct cannulation. The positional distribution of MCF in the dietary fat had no significant effect on the lymph flow, triacylglycerol output, phospholipid output, lipid composition of chylomicrons, or the particle size. The positional distribution of MCF in the synthetic triacylglycerol was maintained in the chylomicron triacylglycerol. These results showed that MCF in the dietary triacylglycerol is transported into lymphatics and the positional distribution is well preserved in chylomicron triacylglycerol.     

Porous Titania Ceramic Prepared by Mimicking Silicified Wood

A porous titania ceramic with a woodlike microstructure that was analogous to silicified wood was prepared. The production of "titanified wood" was performed using the following process: (i) introduction of titanium tetraisopropoxide into wood materials via vacuum infiltration, (ii) hydrolysis of the titanium tetraisopropoxide in the cell structure to form a titania gel, and (iii) firing at a temperature of 600°–1400°C in air. The resulting titania ceramic had the same external and internal forms of the original wood.     

Mixing mechanism of three‐tip kneading block in twin screw extruders

In recent years, twin screw extruders have been applied to various kinds of polymer processing. It has been important to find their optimum geometrical configurations and operational processing conditions for the best performance of extrusions and products. Many engineers have been evolving numerical and the experimental methods to characterize the mixing performance for twin screw extruders. We have carried out three‐dimensional flow simulations of kneading blocks in intermeshing co‐rotating twin screw extruders by using the finite element method to quantify their ability in distributive and dispersive mixing. We discuss their performance in distributive mixing for three different type of kneading blocks in terms of the residence time distribution and the nearest distance between markers at various periods of time, by using the marker tracking method. Those numerical techniques and applications of mixing indices have enabled us to quantify and evaluate their abilities in distributive mixing of kneading blocks in twin screw extruders.     

Differences in Sterol Composition between Male and Female Gonads of Dominant Limpet Species

The present study demonstrated here for the first time that there are statistically significant differences in sterol composition between male and female gonads of the dominant limpets Cellana grata and Cellana toreuma, which are intertidal gastropods. Among 11 different sterols identified in this study, unusually high levels (11.2–19.8% of total sterols) of the Δ⁸-sterols 5α-cholest-8-en-3β-ol (zymostenol) and 5α-cholesta-8,24-dien-3β-ol (zymosterol), which have never been reported in aquatic invertebrate gonads, were present in only the male gonads.