Thermal Expansion of Solid Solutions in the ZrTiO4—In2O3—M2O5 (M = Sb, Ta) System

Axial and dilatometric thermal expansions and phase transformations were studied for solid solutions having the α-PbO₂ structure in the ZrTiO₄—In₂O₃—M₂O₅ (M = Sb, Ta) system with nominal formulas of Zr _x Ti _y In _z Sb _z O₄ and Zr _x Ti _y In _z Ta _z O₄ where x + y + 2 z = 2. With increased substitution of z , the cell volume increased, the difference in the b parameters at room temperature between those quenched from 1400° and 1000°C decreased, and the thermal expansion decreased. The axial thermal expansion of ZrTi _y In _z · Ta _z O₄ with z = 0.3 was almost identical with that of HfTiO₄, and those with z = 0.4 and z = 0.45 were smaller than that of HfTiO₄. Unit-cell volumes of these compound were compared with those of single oxides to make it clear that the unit-cell volume of ZrTiO₄ was small anomalously and to distinguish the normal and abnormal substitution systems. These results were explained by the working hypothesis proposed for these compounds.     

The 2-NN Rule for More Accurate NN Risk Estimation

By proper design of a nearest-neighbor (NN) rule, it is possible to reduce effects of sample size in NN risk estimation. The 2-NN rule for the two-class problem eliminates the first-order effects of sample size. Since its asymptotic value is exactly half that of the 1-NN rule, it is possible to substitute the 2-NN rule for the 1-NN rule with a resultant increase in accuracy. For further stabilization of the risk estimate with respect to sample size, 2-NN polarization is suggested. Examples are included. The 2-NN approach is extended to M-class and 2k-NN.     

Structural approach to nanoscience: a case study of complex and cluster formation in ZnBr2–ZnCl2 melts

Although the melt structure of glass-forming ZnCl₂ has so far been well studied, there exists quite little information on the structural change due to anion-substitution. In the present work, the short-range structure of ZnCl₂–ZnBr₂ mixture melts was analyzed systematically by time-of-flight pulsed neutron diffraction techniques, Raman spectroscopy, molecular orbital calculations, and molecular dynamics simulations. According to radial distribution analysis, it was found that there were tetrahedral structural units of ligand-substituted [ZnCl_nBr_4−n]²⁻ (n=0–4) in these melts, not implying the simple mixing of [ZnCl₄]²⁻ and [ZnBr₄]²⁻ units. Further detailed estimation indicated that the ligand-substituted complex anions were linked with each other by sharing a common anion.     

Psychological Stress Exacerbates Inflammation of the Ileum via the Corticotropin-Releasing Hormone-Mast Cell Axis in a Mouse Model of Eosinophilic Enteritis

The effects of psychological stress on eosinophilic gastrointestinal disorders have not been elucidated. This study investigated the effects of psychological stress in a mouse model of eosinophilic enteritis (EoN). BALB/c mice were treated with ovalbumin (OVA) to create an EoN model and subjected to either water avoidance stress (WAS) or sham stress (SS). Microscopic inflammation, eosinophil and mast cell counts, mRNA expression, and protein levels of type 2 helper T cell (Th2) cytokines in the ileum were compared between groups. We evaluated ex vivo intestinal permeability using an Ussing chamber. A corticotropin-releasing hormone type 1 receptor (CRH-R1) antagonist was administered before WAS, and its effects were analyzed. WAS significantly increased diarrhea occurrence and, eosinophil and mast cell counts, and decreased the villus/crypt ratio compared to those in the SS group. The mRNA expression of CRH, interleukin IL-4, IL-5, IL-13, eotaxin-1, and mast cell tryptase β2 significantly increased, and the protein levels of IL-5, IL-13, and OVA-specific immunoglobulin E (IgE) also significantly increased in the WAS group. Moreover, WAS significantly increased the intestinal permeability. The CRH-R1 antagonist significantly inhibited all changes induced by WAS. Psychological stress exacerbated ileal inflammation via the CRH-mast cell axis in an EoN mouse model.     

Pathogenic Impact of α-Synuclein Phosphorylation and Its Kinases in α-Synucleinopathies

α-Synuclein is a protein with a molecular weight of 14.5 kDa and consists of 140 amino acids encoded by the SNCA gene. Missense mutations and gene duplications in the SNCA gene cause hereditary Parkinson’s disease. Highly phosphorylated and abnormally aggregated α-synuclein is a major component of Lewy bodies found in neuronal cells of patients with sporadic Parkinson’s disease, dementia with Lewy bodies, and glial cytoplasmic inclusion bodies in oligodendrocytes with multiple system atrophy. Aggregated α-synuclein is cytotoxic and plays a central role in the pathogenesis of the above-mentioned synucleinopathies. In a healthy brain, most α-synuclein is unphosphorylated; however, more than 90% of abnormally aggregated α-synuclein in Lewy bodies of patients with Parkinson’s disease is phosphorylated at Ser129, which is presumed to be of pathological significance. Several kinases catalyze Ser129 phosphorylation, but the role of phosphorylation enzymes in disease pathogenesis and their relationship to cellular toxicity from phosphorylation are not fully understood in α-synucleinopathy. Consequently, this review focuses on the pathogenic impact of α-synuclein phosphorylation and its kinases during the neurodegeneration process in α-synucleinopathy.     

Organic–Inorganic Nanohybrids as Novel Thermoelectric Materials: Hybrids of Polyaniline and Bismuth(III) Telluride Nanoparticles

Thermoelectric materials have received much attention recently from the viewpoint of global environmental issues and effective utilization of energy resources. Especially those effective at relatively low temperature, such as below 100°C, which are usually abandoned without use, have become noteworthy recently. From this point of view, organic thermoelectric materials are most attractive, because they could be prepared at low cost and applied in various locations due to their flexibility. We have investigated the thermoelectric properties of organic conducting polymers such as polyaniline, polypyrrole, and polyphenylenevinylene, and succeeded in increasing the thermoelectric performance by selecting dopants, stretching conducting films, etc. Recently we have focused on new systems of organic–inorganic hybrid thermoelectric materials. Herein we present the preparation of a novel system of hybrids of polyaniline and bismuth(III) telluride nanoparticles, starting from bismuth(III) chloride and tetrachlorotellurium by using polyvinylpyrrolidone as a protecting reagent, as well as their thermoelectric properties. The hybrids prepared by this particular method showed much higher thermoelectric performance than the starting organic conducting polymer.     

Dielectric properties of tissue-equivalent liquids and their effects on specific absorption rate

The radio frequency safety of mobile phones has been evaluated in terms of specific absorption rate (SAR). Standard methods for measurement of the SAR, including recipes for tissue-equivalent dielectric liquids, have recently been the subject of discussion among international standards organizations. Standards currently recommend glycol-type liquids as tissue-equivalent liquids for frequencies above 1 GHz. Although the ingredients are specified in the recipes provided, some fundamental information, such as the stability of dielectric properties, remains unclear. We measured the change of dielectric properties with time and with temperature of tissue-equivalent liquids recommended in the standard documents, and evaluated their effects on SAR. The conductivity decreased with increasing temperature in all glycol-type specimens. The permittivity, on the other hand, was almost constant. With the evaporation of water, the permittivity decreased, although the conductivities remained constant. Experimental results proved that dielectric properties are affected by environmental conditions, and that it is inevitably necessary to adjust the dielectric properties regularly, through the addition of ingredients, in order to follow the standards. The SAR values, however, were not affected significantly by the change in dielectric properties; thus, a larger tolerance of the dielectric properties may be acceptable in practical SAR measurements.     

EACLE : Energy-Aware Clustering Scheme with Transmission Power Control for Sensor Networks

In this paper, we propose a new energy efficient clustering scheme with transmission power control named “EACLE” (Energy-Aware CLustering scheme with transmission power control for sEnsor networks) for wireless sensor networks, which are composed of the following three components; “EACLE clustering” is a distributed clustering method by means of transmission power control, “EACLE routing” builds a tree rooted at a sink node and sets the paths from sensor nodes taking energy saving into consideration, and “EACLE transmission timing control” changes the transmission timing with different levels of transmission power to avoid packet collisions and facilitates packet binding. With an indoor wireless channel model which we obtained from channel measurement campaigns in rooms and corridors and an energy consumption model which we obtained from a measurement of a chipset, we performed computer simulations to investigate the performance of EACLE in a realistic environment. Our simulation results indicate that EACLE outperforms a conventional scheme such as EAD (Energy-Aware Data-centric routing) in terms of communication success rate and energy consumption. Furthermore, we fully discuss the impact of transmission power and timing control on the performance of EACLE.     

Mechanical and AC loss properties in mono-and multi-filamentary Bi-223 Ag-sheathed tapes

The evaluation of the bending strain tolerance and AC loss properties for monoand multi-filamentary Bi-2223 Ag-sheathed tape were carried out at liquid nitrogen temperature. For tapes with a filament number of over 19, the critical current (I_c) was maintained at the same values up to the bending strain of 0.3%, although the I_c of the mono-filamentary tape at the condition of 0.2% strain degraded to 90% of the value for the no-strain condition. The AC loss of the monofilamentary tape was the hysteresis type. On the contrary, the AC loss of the multi-filamentary tape was substantially dominated by the eddy current loss in the Ag matrix.     

Transient phenomena of space charge distributions in polypropylene laminated paper

In a multilayer insulator made of two or more materials with different dielectric constants and conductivities, internal space change accumulates at their interfaces. If the local field is increased by the accumulated charge, the electric durability of the insulator should be decreased. In this paper, we describe the space charge accumulation measured when oil-impregnated PPLP (polypropylene laminated paper), which consists of three layers, kraft paper, polypropylene (PP), and kraft paper, was subjected to a strong dc electric field. The experimental results suggest that internal space charge accumulates at both surfaces of a PP layer and that the electric field in the kraft paper layers disappears. © 1998 Scripta Technica, Electr Eng Jpn, 124(1): 1–6, 1998