Development of a new heterojunction structure (ACJ -HIT) and its application to polycrystalline silicon solar cells

A new solar cell structure named HIT (Heterojunction with Intrinsic Thin layer) has been developed based on new artificially constructed junction (ACJ) technology. In this structure a non-doped a-Si thin layer was inserted between the p(a-Si)/n(c-Si) heterojunction, improving the output characteristics and achieving a conversion efficiency of 18.1%. This structure was applied to cast polycrystalline silicon solar cells of a practical size. A high conversion efficeincy of 13.6% was obtained with a cell size of 10 cm × 10 cm using various technologies, including hydrogen plasma passivation.     

Maresin-1 and Inflammatory Disease

Inflammation is an essential action to protect the host human body from external, harmful antigens and microorganisms. However, an excessive inflammation reaction sometimes exceeds tissue damage and can disrupt organ functions. Therefore, anti-inflammatory action and resolution mechanisms need to be clarified. Dietary foods are an essential daily lifestyle that influences various human physiological processes and pathological conditions. Especially, omega-3 fatty acids in the diet ameliorate chronic inflammatory skin diseases. Recent studies have identified that omega-3 fatty acid derivatives, such as the resolvin series, showed strong anti-inflammatory actions in various inflammatory diseases. Maresin-1 is a derivative of one of the representative omega-3 fatty acids, i.e., docosahexaenoic acid (DHA), and has shown beneficial action in inflammatory disease models. In this review, we summarize the detailed actions of maresin-1 in immune cells and inflammatory diseases.     

Modification of bismaleimide resin by poly(propylene phthalate), poly(butylene phthalate) and related (co)polyesters

Aromatic polyesters were prepared and used to decrease the brittleness of the bismaleimide resin composed of 4,4′-bismaleimidediphenyl methane (BMI) and o,o′-diallyl bisphenol A (DBA) (Matrimid 5292 resin). The aromatic polyesters included poly(propylene phthalate) (PPP), poly(2,2-dimethylpropylene phthalate) (PDPP), poly(butylene phthalate) (PBP) and poly(butylene phthalate-co-butylene terephthalate) (50mol% terephthalate unit) (PBPT). The polyesters were effective modifiers for decreasing the brittleness of the bismaleimide resin. For example, inclusion of 20wt% PPP (MW 18700) led to 50% increase in the fracture toughness (K_IC) with retention of flexural properties and a slight loss of the glass transition temperature, compared with the mechanical and thermal properties of the unmodified cured bismaleimide resin. Micro-structures of the modified resins were examined by scanning electron microscopy and dynamic viscoelastic analysis. The thermal stability of the modified resins was slightly lower than that of the unmodified resin as determined by thermogravimetric analysis. The toughening mechanism is discussed in terms of the morphological and dynamic viscoelastic behaviour of the modified bismaleimide resin system. © 1998 SCI.     

Simple chemical syntheses of TAG monohydroperoxides

For the purpose of synthesizing standards to be used in the quantification of TAG hydroperoxides, three TAG (1,2-dioleoyl-3-palmitoylglycerol, 1-oleoyl-2-linoleoyl-3-palmitoylglycerol, and triolein) monohydroperoxides were chemically synthesized as authentic specimens. TAG were prepared by using a simple condensation in pyridine of glycerol and the corresponding acid chlorides. These TAG were then converted into monohydroperoxides by a photosensitized peroxidation. The synthesized monohydroperoxides were analyzed by normal-phase and RP-HPLC. The results of normal-phase HPLC analysis showed that monohydroperoxides from a corresponding TAG were a mixture of regioisomers. In RP-HPLC, however, the regioisomers of monohydroperoxides were not separated and gave a single peak, which may improve the sensitivity for the detection of TAG monohydroperoxides. In this study TAG monohydroperoxide standards were synthesized; these will be useful for the study of yet unknown biological and pathological roles of TAG hydroperoxides.     

Preparation and characterization of natural rubber dispersed in nano-matrix

Preparation of a model nano-matrix-dispersed polymer was investigated in terms of graft-copolymerization of deproteinized natural rubber latex with styrene, using tert-butyl hydroperoxide/tetraethylenepentamine as an initiator. The products were characterized by ¹H-NMR spectroscopy and size-exclusion-chromatography after ozonolysis. The grafting efficiency of styrene was found to be more than 90% under the best condition of the graft-copolymerization. The morphology of the film specimens, prepared from graft-copolymers, was observed by transmission electron microscopy after staining the films with OsO₄. Natural rubber particle of about 0.5 μm in diameter was dispersed in polystyrene matrix of about 15 nm in thickness.     

Modification of cyanate ester resin by soluble polyimides

Soluble polyimides (PIs) were prepared as random or multiblock types with 4,4′‐(hexafluoroisopropylidene) diphthalic anhydride (6FDA) and 3,3′,4,4′‐biphenyltetracarboxylic dianhydride (s‐BPDA) as acid dianhydride components and 4,4′‐bis(m‐aminophenoxy) diphenyl sulfone (m‐BAPS) as a diamine component by a one‐pot process and used to improve the brittleness of the cyanate ester resin. Random‐type PIs were more effective as modifiers than multiblock‐type PIs. The morphologies of the modified resins depended on PI structure, molecular weight, and concentration. The most effective modification of the cyanate ester resin was attained because of a heterogeneous phase structure composed of a flat matrix phase and phase‐inverted structures of the modified resin; a 15 wt % inclusion of a random PI (weight‐average molecular weight = 63,400) composed of 6FDA, s‐BPDA, and m‐BAPS (0.5/0.5/1.0 molar ratio) led to a 65% increase in the fracture toughness for the modified resin with a slight loss of flexural strength and a retention of flexural modulus and glass‐transition temperature, compared with the values for the unmodified resin. Water absorptivity of the modified resin was comparable to that of the unmodified resin up to 400 h, and then, water absorption of the modified resins increased considerably. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1–11, 2003     

Neuroprotective Effects of Liraglutide for Stroke Model of Rats

The number of diabetes mellitus (DM) patients is increasing, and stroke is deeply associated with DM. Recently, neuroprotective effects of glucagon-like peptide-1 (GLP-1) are reported. In this study, we explored whether liraglutide, a GLP-1 analogue exerts therapeutic effects on a rat stroke model. Wistar rats received occlusion of the middle cerebral artery for 90 min. At one hour after reperfusion, liraglutide or saline was administered intraperitoneally. Modified Bederson’s test was performed at 1 and 24 h and, subsequently, rats were euthanized for histological investigation. Peripheral blood was obtained for measurement of blood glucose level and evaluation of oxidative stress. Brain tissues were collected to evaluate the level of vascular endothelial growth factor (VEGF). The behavioral scores of liraglutide-treated rats were significantly better than those of control rats. Infarct volumes of liraglutide-treated rats at were reduced, compared with those of control rats. The level of derivatives of reactive oxygen metabolite was lower in liraglutide-treated rats. VEGF level of liraglutide-treated rats in the cortex, but not in the striatum significantly increased, compared to that of control rats. In conclusion, this is the first study to demonstrate neuroprotective effects of liraglutide on cerebral ischemia through anti-oxidative effects and VEGF upregulation.     

Effects of pressure and temperature on dyeing acrylic fibres with basic dyes in supercritical carbon dioxide

The dyeing of acrylic fibre with CI Basic Blue 47 has been investigated using an ammonium carboxylate perfluoropolyether as an auxiliary in order to perform the reverse micellar system in supercritical carbon dioxide media. The basic dye was satisfactorily solubilised in the interior of the reverse micelle in the system, and dyeability in the supercritical carbon dioxide media was excellent, even in the absence of a retardant and/or an acid. The optimum proton-rich condition for dyeing of acrylic fabric is performed in reverse micelle aggregates and the proton-rich water pool is suitable for dye uptake by the fibre even without the presence of additives. Changes in glass transition temperature of acrylic fibre in the carbon dioxide media also influence the dyeing behaviour of acrylic fabric.     

Feasibility of high performance in p-type Ge1−xBixTe materials for thermoelectric modules

GeTe is a promising candidate for the fabrication of high-temperature segments for p-type thermoelectric (TE) legs. The main restriction for the widespread use of this material in TE devices is high carrier concentration (up to ∼ 10²¹ cm⁻³), which causes the low Seebeck coefficient and high electronic component of thermal conductivity. In this work, the band structure diagram and phase equilibria data have been effectively used to attune the carrier concentration and to obtain the high TE performance. The Ge_1−xBi_xTe (x = 0.04) material prepared by the Spark plasma sintering (SPS) technique demonstrates a high power factor accompanied by moderate thermal conductivity. As a result, a significantly higher dimensionless TE figure of merit ZT = 2.0 has been obtained at ∼ 800 K. Moreover, we are the first to propose that application of the developed Ge_1−xBi_xTe (x = 0.04) material in the TE unicouple should be accompanied by SnTe and CoGe₂ transition layers. Only such a unique solution for the TE unicouple makes it possible to prevent the negative effects of high contact resistance and chemical diffusion between the segments at high temperatures.