A new method for transient stability analysis

This paper proposes a brand‐new method for transient stability analysis in power systems. The proposed method directly computes the critical trajectory for a given contingency to obtain the critical condition of the studied system. Although the method may be useful for general nonlinear dynamic systems, it is applied to the problem of obtaining a controlling UEP, unstable equilibrium point, which provides inevitable information for the energy function methods to assess transient stability. Namely, the proposed method effectively yields a critical trajectory on PEBS together with the controlling UEP, thus improving the conventional BCU method. The effectiveness of the proposed method is demonstrated in 3‐machine 9‐bus and 6‐machine 30‐bus systems. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 159(3): 26–33, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20245     

Glutathione levels of the human crystalline lens in aging and its antioxidant effect against the oxidation of lens proteins

This paper reports the role of glutathione (GSH) in the crystalline lens as an antioxidant against the oxidation of lens protein. GSH levels in normal lenses decreased gradually with increasing age, from approximately 5 mumol per g lens (wet weight) to 3 mumol per g lens (wet weight). On the other hand, levels of oxidized GSH in the lenses increased until the age of 40. After that, it remained almost constant at the level of approximately 0.9 mumol per g lens. Protein-bound GSH levels in both soluble and insoluble lens proteins dropped noticeably in the 50-year and older age groups, although there were significant differences in levels between both fractions. A decrease of tryptophan and tyrosine residues in lens proteins was proportional to a decrease in GSH levels in the lens as a result of aging. Those residue levels in the cataractous lenses were approximately half those in the normal lens proteins, and GSH levels in such lenses were almost one-tenth that in the normal lens. This study revealed that GSH may play an important role in preventing the oxidation of lens proteins from various oxidants. Furthermore, it is conceivable that these normal changes in GSH levels in the lenses increase the vulnerability of the lens to senile cataractogenesis.     

Antitussive effect of dihydroetorphine in mice

The present study examined the opioid receptors involved in the antitussive effect of dihydroetorphine in mice. Dihydroetorphine suppressed coughs dose dependently at doses between 0.1-1 micrograms/kg i.p. Blockade of mu-opioid receptors by pretreatment with beta-funaltrexamine significantly reduced the antitussive effect of dihydroetorphine. Furthermore, the antitussive effect of dihydroetorphine was also antagonized by nor-binaltorphimine, a kappa-opioid receptor antagonist. However, pretreatment with naltrindole, a delta-opioid receptor antagonist, did not affect the antitussive effect of dihydroetorphine. These results indicate that the antitussive effect of dihydroetorphine is mediated by the activation of mu-opioid receptors and of kappa-opioid receptors, but not delta-opioid receptors.     

A novel adrenaline derivative, AZ002, and its hypoglycemic action in yellow KK mice

A new device has been designed to provide anchorage for orthodontic tooth movement. It is a disk, textured and hydroxylapatite coated on one side, with an internal thread on the other side. It is placed on palatal bone and, after integration, can be connected to teeth for anchorage. This article reviews a dog study demonstrating unilateral tooth movement towards the "onplant" and a monkey study mimicking its use to anchor the molars for anterior retraction.     

Crystal quality of a 6H-SiC layer grown over macrodefects by liquid-phase epitaxy: a Raman spectroscopic study

Liquid-phase epitaxial (LPE) growth on silicon carbide simultaneously covers macroscale defects, e.g. micropipes, and improves the quality of the crystal. In this study, an epi-layer grown over a macrodefect was evaluated by micro-Raman scattering spectroscopy. Before the growth process, the density of the stacking fault was high and the carrier density spatially inhomogeneous in the vicinity of the macrodefects. On the other hand, after growth, the layer over the macrodefect displayed good quality; the density of the stacking fault was less than that before growth and the homogeneity of the carrier density improved.     

X-ray computed tomography imaging of a tumor with high sensitivity using gold nanoparticles conjugated to a cancer-specific antibody via polyethylene glycol chains on their surface

Contrast agents are often used to enhance the contrast of X-ray computed tomography (CT) imaging of tumors to improve diagnostic accuracy. However, because the iodine-based contrast agents currently used in hospitals are of low molecular weight, the agent is rapidly excreted from the kidney or moves to extravascular tissues through the capillary vessels, depending on its concentration gradient. This leads to nonspecific enhancement of contrast images for tissues. Here, we created gold (Au) nanoparticles as a new contrast agent to specifically image tumors with CT using an enhanced permeability and retention (EPR) effect. Au has a higher X-ray absorption coefficient than does iodine. Au nanoparticles were supported with polyethylene glycol (PEG) chains on their surface to increase the blood retention and were conjugated with a cancer-specific antibody via terminal PEG chains. The developed Au nanoparticles were injected into tumor-bearing mice, and the distribution of Au was examined with CT imaging, transmission electron microscopy, and elemental analysis using inductively coupled plasma optical emission spectrometry. The results show that specific localization of the developed Au nanoparticles in the tumor is affected by a slight difference in particle size and enhanced by the conjugation of a specific antibody against the tumor.     

Application of nonlinear regression in the development of a wide range formulation for HCFC-22

An equation of state has been developed for HCFC-22 for temperatures from the triple point (115.73 K) to 550 K, at pressures up to 60 MPa. Based on comparisons between experimental data and calculated properties, the accuracy of the wide-range equation of state is ±0.1% in density, ±0.3% in speed of sound, and ±1.0% in isobaric heat capacity, except in the critical region. Nonlinear fitting techniques were used to fit a liquid equation of state based onP--T, speed of sound, and isobaric heat capacity data. Properties calculated from the liquid equation of state were then used to expand the range of validity of the wide range equation of state for HCFC-22.Paper presented at the Twelfth Symposium on Thermophysical Properties, June 19–24, 1994, Boulder, Colorado, U.S.A.     

Enargite Cu3PS4: A Cu–S‐Based Thermoelectric Material with a Wurtzite‐Derivative Structure

Compound semiconductors derived from ZnS (zincblende and wurtzite) with tetrahedral framework structures have functions for various applications. Examples of such materials include Cu–S‐based materials with zincblende‐derivative structures, which have attracted attention as thermoelectric (TE) materials over the past decade. This study illuminates superior TE performance in polycrystalline samples of enargite Cu₃P_1?xGe_xS₄ with a wurtzite‐derivative structure. The substitution of Ge for P dopes holes into the top of the valence band composed of Cu‐3d and S‐3p, whereby its multiband characteristic leads to a high TE power factor. Furthermore, a reduction in the grain size to 50–300 nm can effectively decrease phonon mean free paths, leading to low thermal conductivity. These features result in a dimensionless TE figure of merit ZT of 0.5 at 673 K for the x = 0.2 sample. Environmentally benign and low‐cost characteristics of the constituent elements of Cu₃PS₄, as well as its high‐performance thermoelectricity, make it a promising candidate for large‐scale TE applications. Furthermore, this finding extends the development field of Cu–S‐based TE materials to those with wurtzite‐derivative structures.     

Formation conditions of mutual adaptation in human-agent collaborative interaction

When an adaptive agent works with a human user in a collaborative task, in order to enable flexible instructions to be issued by ordinary people, it is believed that a mutual adaptation phenomenon can enable the agent to handle flexible mapping relations between the human user’s instructions and the agent’s actions. To elucidate the conditions required to induce the mutual adaptation phenomenon, we designed an appropriate experimental environment called “WAITER” (Waiter Agent Interactive Training Experimental Restaurant) and conducted two experiments in this environment. The experimental results suggest that the proposed conditions can induce the mutual adaptation phenomenon.     

Role of intracellular calcium on the modulation of naloxone-precipitated withdrawal jumping in morphine-dependent mice by diabetes

The role of intracellular calcium in the modifications of naloxone-precipitated withdrawal jumping in morphine-dependent mice by diabetes was examined. Naloxone-precipitated withdrawal jumping was significantly less in morphine-dependent diabetic mice than in morphine-dependent non-diabetic mice. Intracerebroventricular (i.c.v. ) pretreatment with ryanodine attenuated naloxone-precipitated withdrawal jumping in morphine-dependent non-diabetic mice. However, naloxone-precipitated withdrawal jumping in morphine-dependent diabetic mice was not affected by i.c.v. pretreatment with ryanodine. Moreover, i.c.v. pretreatment with thapsigargin, a Ca2+-ATPase inhibitor, enhanced naloxone-precipitated withdrawal jumping in morphine-dependent non-diabetic mice, but not in morphine-dependent diabetic mice. The noradrenaline (NA) turnover in the frontal cortex in morphine-dependent non-diabetic mice, but not in morphine-dependent diabetic mice, was significantly increased by naloxone injection. Naloxone-induced enhancement of NA turnover in morphine-dependent non-diabetic mice, but not in morphine-dependent diabetic mice, was blocked by i.c.v. pretreatment with ryanodine. In contrast to ryanodine, thapsigargin enhanced naloxone-induced enhancement of NA turnover in morphine-dependent non-diabetic mice. These results suggest that increased intracellular calcium augmented naloxone-precipitated withdrawal jumping and the turnover rate of NA in the frontal cortex in morphine-dependent non-diabetic mice. Furthermore, it seems likely that the attenuation of naloxone-precipitated withdrawal jumping in morphine-dependent diabetic mice may be due, in part, to the dysfunction of intracellular calcium store.