Theoretical Investigation of Lattice Thermal Vibration Effects on Phase Equilibria Within Cluster Variation Method

First-principles phase equilibria calculations often overestimate an order-disorder transition temperature due to the neglect of local lattice distortion effects originated from the mixture of elements of different atomic sizes. The lattice vibration effects introduced through the Debye-Grüneisen theory within the quasi-harmonic approximation has proven to be quite effective in circumventing the inconveniences. With the preferential enhancement of the stability of a disordered phase by introducing the lattice vibration effects, the transition temperature was reduced considerably. In order to gain further insight into the lattice vibration effects, a systematic investigation of the vibrational free energy of the Debye-Grüneisen theory is attempted on the two-dimensional square lattice which constitutes a prototype study prior to the first-principles calculations on realistic alloy systems. A particular focus of the present study is placed on the effects of Debye temperatures of constituent phases on the transition temperature. It is shown that lattice softening by lattice vibration stabilizes the disordered phase by reducing the energy expended to accommodate atoms of different sizes, which is manifested by the reduction of the curvature of the atomic potentials. It is, however, predicted that an opposite case can also take place. When the Debye temperature of an ordered phase is lower than that of the pure metals, the ordered phase is more stabilized and the inclusion of the lattice vibration effects in the free energy raises the resultant transition temperature.     

Involvement of Autophagy in Rat Tail Static Compression-Induced Intervertebral Disc Degeneration and Notochordal Cell Disappearance

The intervertebral disc is the largest avascular low-nutrient organ in the body. Thus, resident cells may utilize autophagy, a stress-response survival mechanism, by self-digesting and recycling damaged components. Our objective was to elucidate the involvement of autophagy in rat experimental disc degeneration. In vitro, the comparison between human and rat disc nucleus pulposus (NP) and annulus fibrosus (AF) cells found increased autophagic flux under serum deprivation rather in humans than in rats and in NP cells than in AF cells of rats (n = 6). In vivo, time-course Western blotting showed more distinct basal autophagy in rat tail disc NP tissues than in AF tissues; however, both decreased under sustained static compression (n = 24). Then, immunohistochemistry displayed abundant autophagy-related protein expression in large vacuolated disc NP notochordal cells of sham rats. Under temporary static compression (n = 18), multi-color immunofluorescence further identified rapidly decreased brachyury-positive notochordal cells with robust expression of autophagic microtubule-associated protein 1 light chain 3 (LC3) and transiently increased brachyury-negative non-notochordal cells with weaker LC3 expression. Notably, terminal deoxynucleotidyl transferase dUTP nick end labeling-positive apoptotic death was predominant in brachyury-negative non-notochordal cells. Based on the observed notochordal cell autophagy impairment and non-notochordal cell apoptosis induction under unphysiological mechanical loading, further investigation is warranted to clarify possible autophagy-induced protection against notochordal cell disappearance, the earliest sign of disc degeneration, through limiting apoptosis.     

Thermal model of human body fitted with individual characteristics of body temperature regulation

To develop a thermal model that can predict the thermal responses of the human body under given environmental conditions, it is necessary for the model to be fitted with the individual characteristics of human body temperature regulation. As the basis for this, in this paper, it is shown that the coefficients that represent the thermoregulatory responses in the two-node model (thermal model of human body) can be identified for individuals. Six coefficients related to the regulation of sweating and skin blood flow in the two-node model are tuned for the individuals involved in the experiments—the core and skin temperatures calculated by the model are fitted with the measured results for the entire thermal transient processes, including exposures to heat and cold.     

Battery performances and thermal stability of polyacrylonitrile nano-fiber-based nonwoven separators for Li-ion battery

The microporous polyacrylonitrile (PAN) nonwoven separators have been developed by using electrospun nano-fibers with homogeneous diameter of 380 and 250 nm. The physical, electrochemical and thermal properties of the PAN nonwovens were characterized. The PAN nonwovens possessed homogeneous pore size distribution with similar pore size to the conventional microporous membrane separator. Moreover, the PAN nonwovens showed higher porosities, lower gurley values and better wettabilities than the conventional polyolefin microporous separator. Cells with the PAN nonwovens showed better cycle lives and higher rate capabilities than that of a cell with conventional one. Any internal short circuit was not observed for the cells with the PAN nonwovens during charge–discharge test. Hot oven tests for the charged cells up to 4.2 V have revealed that the PAN nonwoven was thermally stable at 120 °C, but showed shrinkage of about 26% isotropically after the test at 150 °C for 1 h. The Celgard membrane showed uniaxial shrinkage of about 30% along the machine direction at 150 °C for 1 h.     

Comparison of phenolic compositions between common and tartary buckwheat (Fagopyrum) sprouts

The phenolic compositions of non-germinated/germinated seeds and seed sprouts (at 6–10 day-old) of common (Fagopyrum esculentum Möench) and tartary (Fagopyrum tataricum Gaertn.) buckwheats were investigated. Phenolic compounds, including chlorogenic acid, four C-glycosylflavones (orientin, isoorientin vitexin, isovitexin), rutin and quercetin, were determined in the seed sprouts by high-performance liquid chromatography (HPLC). In the edible parts of common buckwheat sprouts, individual phenolics significantly increased during sprout growth from 6 to 10 days after sowing (DAS), whereas in tartary buckwheat sprouts they did not. While the sum contents of phenolic compounds in the edible part (mean 24.4 mg/g DW at 6–10 DAS) of tartary buckwheat sprouts were similar to those of common buckwheat sprouts, rutin contents in the non-germinated/germinated seeds (mean 14.7 mg/g DW) and edible parts (mean 21.8 mg/g DW) of tartary buckwheat were 49- and 5-fold, respectively, higher than those of common buckwheat. Extracts of the edible parts of both species showed very similar free radical-scavenging activities (mean 1.7 μmol trolox eq/g DW), suggesting that the overall antioxidative activity might be affected by the combination of identified phenolics and unidentified (minor) components. Therefore, buckwheat seed sprouts are recommended for their high antioxidative activity, as well as being an excellent dietary source of phenolic compounds, particularly tartary buckwheat sprouts, being rich in rutin.     

Imparting cell adhesion to poly(vinyl alcohol) hydrogel by coating with hydroxyapatite thin film

To impart good cell adhesion to poly(vinyl alcohol) hydrogel (PVA-H) as an artificial articular cartilage, hydroxyapatite thin film 300 nm thick was deposited by a pulsed laser deposition technique on PVA-H, which has virtually no cell adhesion. A cell culture method was used to study the effect of hydroxyapatite deposition on PVA-H upon cell adhesion among mouse fibroblasts. The cell adhesion of water content 33% PVA-H coated with the amorphous hydroxyapatite film showed a maximum as high as that of commonly used tissue culture dishes. This technique was also effective for improving cell adhesion, even on a higher water content (53%) PVA-H. This is a novel technique to improve the biocompatibility and attachment of PVA-H and with the underlying bone and natural cartilage.     

Progress in the HDR/HWR projects at Tohoku University, Japan

This paper presents an outline of the series of HDR/HWR projects conducted by Tohoku University since 1983, starting with the Γ-project, which was followed by the HWR, Fractal and MTC projects. The final goal of these projects is to establish/develop the design methodology for engineered geothermal reservoirs. A brief review of each project is also presented, with emphasis upon the progress of the main research topics, such as monitoring of reservoirs by active/passive acoustic techniques, rock mass properties, in situ stress, modeling and simulation and water/rock chemical interaction.     

2,6,10-Tris(bithiophenyl)triphenylene: Synthesis and high-spin alignment in its p-doped radical derivative

2,6,10-Tris[5′-(5-hexyloxyphenyl-2,2′-bithiophenyl)]-3,7,11-tris(hexyloxy)tripheneylene (2) was designed and synthesized as a π-conjugated platform to produce its tris(cationic radical) derivative (1) in a non-Kekulé and nondisjoint fashion. An electrochemical study revealed the chemically reversible redox property of 2. Gaseous antimony pentachloride-doping of 2 dispersed in a polystyrene matrix gave its cationic radical. It was chemically stable with a half-life >2 weeks and displayed a triplet ground state based on an ESR measurement. A high-spin state with S = 3/2 for 1 was proved by the magnetization and magnetic susceptibility.     

Effect of CO2/N2 addition to supercritical methanol on reactivities and fuel qualities in biodiesel production

Addition of the third component to supercritical methanol has been studied in the literature for biodiesel production in order to reduce reaction temperature without deteriorating the reaction rate. However, effect of pressure had often been neglected in the discussion. In this paper, therefore, effect of pressure was examined with hexane, carbon dioxide (CO₂) and nitrogen (N₂) as one of the third components, using batch-type and flow-type reactors. As a result, it was found that an addition of the third component did not contribute to better product yield at constant reaction pressure. Furthermore, the reaction rate was found to be determined by pressure and concentration of the reactants involved in transesterification, not by the function of so-called co-solvent. Additionally, N₂ addition was found to contribute to improvement in oxidation stability and reduction of the total glycerol content, thus offering high-quality biodiesel production.     

Photo-response behavior of Au nano-particle/porphyrin polymer composite device with nano-gapped electrodes

Electrodes with a gap size of 15 ∼ 80 nm could be bridged by porphyrin molecular wires with 50 ∼ 300 nm length. The porphyrin units could be coordinated with Au nano-particles having pyridinyl moiety. The device with both the porphyrin and Au nano-particles showed photo-response characteristics while those without the Au nano-particles showed no response.