Ferroelectric and Photostrictive Properties of Fine-Grained PLZT Ceramics Derived from Mechanical Alloying

Single-phase lead lanthanum zirconate titanate (PLZT) solid solution powder was synthesized from the constituent oxides at ambient temperature through a mechanical alloying (MA) process and was then densified to fine-grained ceramics by sintering and hot-pressing. The anomalous photovoltaic effect (APV) and photoinduced strain of the resultant PLZT ceramics were investigated and analyzed in association with the influence of grain size. It was found that a photoinduced voltage up to 6000 V·cm⁻¹ can be obtained as the grain size is reduced to 0.42 μm. This is extremely high and about three times that achievable in normal micrometer-grained PLZT ceramics. The maximum photoinduced strain of the PLZT ceramics with an average grain diameter of 0.54 μm reached 0.01%, which is equivalent to electric-field-induced strain of common piezoelectric materials.     

Effect of hydrogen radical on growth of μc-Si in hetero-structured SiCx alloy films

The changes of the crystallinity of μc-Si phase are studied in samples deposited with hydrogen dilution ratio, H₂/SiH₄, from 9.0 to 19.0 by hot-wire CVD (Cat-CVD). In the samples deposited at filament temperature, T_f, of 1850 °C, the crystalline fraction and the crystallite size of μc-Si phase increased with increasing the H₂/SiH₄. The carbon content, C/(Si+C), was almost constant. In the XRD patterns, the intensity of Si(1 1 1) peak decreased and that of Si(2 2 0) peak increased with increasing the H₂/SiH₄. In the samples deposited at T_f of 2100 °C with H₂/SiH₄ over 11.4, the μc-Si phase was not formed and the C/(Si+C) increased. The growth mechanism of μc-Si in hetero-structured SiC_x alloy films is discussed.     

Ca(2+)/calmodulin-dependent protein kinase II inhibitor KN-62 inhibits adrenal medullary chromaffin cell functions independent of its action on the kinase

KN-62, an inhibitor of Ca2+/calmodulin-dependent protein kinase II (CaM kinase II), inhibited significantly catecholamine secretion and tyrosine hydroxylase activity stimulated by acetylcholine in cultured bovine adrenal medullary cells. KN-62, however, showed an additional inhibitory effect on acetylcholine-induced 45Ca2+ influx, which is essential for functional responses. Carbachol-stimulated 22Na+ influx, veratridine-induced 22Na+ influx, and 56 mM K(+)-evoked 45Ca2+ influx were also attenuated by KN-62. Inhibitions by KN-62 of these ion influxes were correlated closely with those of catecholamine secretion. KN-04, which is a structural analogue of KN-62 but does not inhibit CaM kinase II activity, elicited inhibitory effects on the three kinds of stimulant-evoked ion influxes with an inhibitory potency similar to KN-62. These results suggest that KN-62 inhibits catecholamine secretion and tyrosine hydroxylase activation due to mainly its ion channel blockade on the plasma membrane rather than the inhibition of CaM kinase II activity in the cells.     

Formation and Microstructures of Whipped Oils Composed of Vegetable Oils and High-Melting Fat Crystals

This paper reports the experimental results of processes used for the formation of whipped oils composed of vegetable oils (salad oil) and high‐melting fat crystals [fully hydrogenated rapeseed oil rich in behenic acid (FHR‐B)]. No emulsifier was added to form this whipped oil. Microprobe FT‐IR spectroscopy, synchrotron radiation microbeam X‐ray diffraction (SR‐μ‐XRD), polarized optical microscopy, and differential scanning calorimetry (DSC) were employed to observe fine fat crystal particles of the most stable polymorph of β (β‐fat crystal), FHR‐B, and their adsorption at the air–oil surface before, during, and after the formation of the whipped oil. The results obtained revealed the following: (1) The preparation of an organogel composed of salad oil and small fibrous β‐fat crystals using a special tempering procedure was a prerequisite for forming whipped oil. (2) The β‐fat crystals were adsorbed at the air–oil surface to encapsulate the air bubbles during the formation process of whipped oil. (3) The values of overrun of the whipped oil reached >200 % after an aeration time of 30 min at 20 °C. (4) The SR‐μ‐XRD experiments demonstrated that the lamellar planes of the β‐fat crystals near the air–oil surface were arranged almost parallel to the air–oil surface plane. The present study provides the first evidence that tiny fat crystal particles may cause aeration in liquid oils without the addition of other whip‐assisting substances such as emulsifier crystals.     

Cu-based spinel catalysts CuB2O4 (B = Fe, Mn, Cr, Ga, Al, Fe0.75Mn0.25) for steam reforming of dimethyl ether

Cu-based spinel-oxides CuB₂O₄ (B = Fe, Mn, Cr, Ga, Al, or Fe_0.75Mn_0.25) were synthesized via a sol–gel method and subsequent solid-state reaction. The spinels mechanically mixed with γ-Al₂O₃ were evaluated for production of hydrogen from dimethyl ether steam reforming (DME SR). The reduction behavior and crystal property of these spinel-oxides, and the Cu oxidation state in spinel catalysts were investigated by temperature-programmed reduction, X-ray diffraction, and X-ray photoelectron spectroscopy techniques. The reduced phases of the Cu-based spinel catalysts that strongly affected the catalytic activity and durability were composed of metallic copper with metal oxides (MnO (B = Mn), Cr₂O₃ (B = Cr), and Al₂O₃ (B = Al)) or with spinels (CuGa₂O₄ (B = Ga), Fe₃O₄ (B = Fe), and MnFe₂O₄ (B = Fe_0.75Mn_0.25). The stability of B metal oxides and the interaction between copper species and B metal oxides significantly contributed to the reforming performance.     

High volume nanoimprint lithography on III/V substrates: Imprint fidelity and stamp lifetime

Nanoimprint lithography (NIL) has developed from an emerging nanoreplication technology into a mature and industrially viable manufacturing technology. It is now by far the fastest and most cost-efficient nanoreplication method available. This technology has been successfully implemented in the manufacturing of High Brightness LED’s. However, manufacturing of HBLED’s in high volume using nanoimprint lithography faces a few particular challenges. Perhaps the most significant is to produce perfectly imprinted nanostructures on the epitaxially grown substrates with high quality and yield. This is especially important since the substrates are expensive and since the imprint step is close to the end of the production process. This means that the value of the processed substrates is very high. In this work, 8000 imprints were produced. Measured data from the imprinted substrates shows consistent results. It is also shown that the 8000 imprints have been performed using the same stamp without significant degradation. After 8000 imprints, the yield from the nanoimprint lithography step is 99.15%.     

Visualization of electroporation-induced temperature rise using temperature-sensitive ink

Irreversible electroporation (IRE) is attracting attention as a new technique to treat tumors, in which electric pulses over a certain threshold perforate the cell membrane and induce necrotic cell death. Since the electric pulses potentially generate the Joule heating around electrodes, successful IRE needs to apply a pulsed voltage high enough for the irreversible perforation yet minimizes the thermal effect on the extracellular matrix in the surrounding tissue. The temperature rise around the electrodes is therefore one of the most important concerns in the IRE. However, no experimental evidence has been reported for the temperature rise because of extremely short pulses used in the IRE. The aim of this study was therefore to establish a new method to detect the temperature rise during the IRE. A key technique is to use temperature-sensitive ink to visualize in situ instantaneous temperature rise. Chromatic change of the ink that depends on the temperature was preliminarily calibrated by a transient short-hot-wire technique combined with color analysis of the ink, and then utilized to determine the temperature distribution after electroporation. The maximum temperature rise was thus successfully visualized after the electroporation using agar gel as a tissue phantom. Our method is useful for direct evaluation of a risk of thermal damage and provides experimental evidence for theoretical study.     

Transcriptional profiling in rats and an ex vivo analysis implicate novel beneficial function of egg shell membrane in liver fibrosis

Egg shell membrane (ESM) is a natural and safe food by-product from egg processing whilst there is little information about the role of ESM as a food component. Effects of dietary ESM on gene expression in rat liver were investigated through DNA microarray comprehensive analysis. The expression of smooth muscle-α-actin, which is a marker of hepatic stellate cells (HSCs) activation, and integrin beta-like 1, decorin, asporin, lumican and collagen type 1 alpha 1, which are components of extracellular matrix (ECM) and involved in the up-regulation of HSCs activation and fibrosis, was found to be significantly down-regulated after 14 days of ESM treatment. Subsequently, serum obtained from rats given ESM diet also suppressed the expression of COL1A1 and COL1A2 in human hepatoma C3A cells. Our in vivo and ex vivo findings demonstrate that these gene alterations may contribute to the beneficial effect of ESM partially through down-regulation of c-jun and c-fos signal transduction thereby blunting HSCs activation and eventually preventing liver fibrosis. These outcomes not only provide novel information about the functional and nutritional availability of ESM, but also might contribute to the field of environmental protection.     

A thin layer including a carbon material improves the rate capability of an electric double layer capacitor

We present a new method to improve the rate capability of an electric double layer capacitor (EDLC) using a thin polymer layer having a high concentration of carbon material on a current collector (CLC). A novel thermocuring coating composed of a glycol-chitosan, a pyromellitic acid and a conductive carbon powder can form stable CLC on a metal foil current collector simply by spreading and curing at 160 °C for a couple of minutes. We compared the performance of some demonstration EDLC cells using three kinds of current collector: a conventional aluminum oxide foil for EDLC, an aluminum foil and an aluminum foil with CLC. The cell with the CLC had a much higher rate capability than the cell without CLC. Only the CLC cell was able to discharge at a current density of 500C. This cell shows a slight deterioration in capacity in a high temperature, continuous charging, life test, and the CLC has a suppressing effect on the internal resistance increase of EDLCs. The use of a CLC film current collector is one of the most effective and simple methods for the improvement of EDLC rate performance. In particular, a current collector consisting of aluminum foil coupled with a CLC promises to be a low cost alternative to the aluminum oxide foil commonly used in EDLCs.