Thermal recovery effect on light-induced degradation of amorphous silicon solar module under the sunlight

The thermal recovery effect from the light-induced degradation under the sunlight is experimentally investigated on the amorphous silicon photovoltaic module (a-Si PV module) for installing directly to the roof flames of wooden houses. To enhance the recovery effect, the heat-insulating material is attached to the back side of the module for increasing the module temperature under the sunlight: the heat-insulated module.The generated power from the heat-insulated module is compared with that from the normal module (without the heat-insulating material) for 2 yr, and it has been cleared that the generated power normalized at 25°C from the heat-insulated module is approximately 7.3% higher than that from the normal one with the average temperature increase of 4.2°C under the sunlight.     

Near-infrared reflection from periodically aluminium-doped zinc oxide thin films

Multilayers of aluminium-doped zinc oxide (Al:ZnO) as a heat-reflection material were prepared by a reactive sputtering method with intermittent Al doping or Al content modulation. A drop in the refractive indices n around the plasma wavelength λ_p of 1456 nm for the optimally-doped Al:ZnO layers formed the periodic distribution of n in the multilayers. The periodic n provided selective reflection of approximately 60% under λ_p and shielded near-infrared solar radiation containing high energy, which was impossible to be reflected from the Al:ZnO monolayer. The selective reflection was accompanied by infrared reflection above λ_p, low emissivity and no subsequent visible reflection, which allowed the multilayers to achieve compatibility between the solar heat gain coefficient of 0.6 and the visible transmittance of nearly 80%.     

Metabolic improvements and use of inexpensive carbon sources in microbial production of polyhydroxyalkanoates

This paper deals with the microbial production of polyhydroxyalkanoates (PHAs), biodegradable thermoplastics which perform excellently as a material, from inexpensive renewable carbon sources. To date, with the help of genetic engineering techniques, it has become possible to design several types of PHAs with different compositions and to enhance the productivities of PHAs. In addition, molecular breeding of PHA biosynthesis enzymes has been demonstrated to improve polymer production. Mutant PHA synthases generated by an in vitro evolution technique have allowed the enhanced production and quality alteration of PHAs. Furthermore, use of inexpensive renewable carbon sources, such as plant oils, waste materials, and carbon dioxide, would be a key for a reduction in PHA production cost.     

Pitfalls in the toxicological analysis of an isobutyl nitrite-adulterated coffee drink

A forensic investigation was carried out on one poisoning case, where cyanide was first detected in an evidence sample of a canned coffee drink. A more complete study revealed that it had been adulterated with isobutyl nitrite (IBN) and not cyanide. We examined the detectivity of IBN and related compounds by headspace gas chromatography and capillary electrophoresis. IBN decomposes to isobutyl alcohol (iBuOH) and nitrite in aqueous solution, and under higher temperature and more acidic conditions, the rate of this reaction becomes more rapid. IBN was also produced by the esterification of iBuOH with nitrite below pH 5. Cyanide was produced in a coffee solution by the addition of nitrite below pH 6. An IBN-spiked canned coffee drink solution was stored at 4 degrees C and periodically analyzed for IBN, iBuOH, nitrite, nitrate, and cyanide. Since the IBN level decreased rapidly, iBuOH was produced in an almost 90% molar yield. Nitrite production reached a maximum of 40% molar recovery on the first day and then gradually disappeared. The nitrate level reached a plateau of approximately 60% molar recovery. Cyanide was also detected, and its level at the 14th day was approximately 0.26% molar recovery. These findings suggest that, in a coffee drink solution, IBN undergoes hydrolysis to produce iBuOH and nitric acid, which is oxidized to nitrate and also produces cyanide through the nonspecific oxidation of organic compounds under acidic conditions.     

Porous biodegradable polyesters. II. Physical properties,morphology, and enzymatic and alkaline hydrolysis of porous poly(ϵ‐caprolactone) films

Porous poly(?‐caprolactone) (PCL) films were prepared by water extraction of poly(ethylene oxide) (PEO) from their solution‐cast phase‐separated blend films and the dependence of their blend ratio [X_PCL = PCL/(PEO + PCL)] and molecular weight of PEO on the porosity, pore size, crystallinity, crystalline thickness, mechanical properties, morphology, and enzymatic and alkaline hydrolysis of the porous PCL films were investigated. The film porosity or extracted weight ratio was in good agreement with the expected values, irrespective of X_PCL and molecular weight of PEO. The maximum pore size was larger for the porous films prepared using PEO having a lower molecular weight, compared with films prepared using PEO having a higher molecular weight at the same X_PCL. Differential scanning calorimetry of the porous PCL films revealed that their crystallinity and crystalline thickness were almost constant, regardless of X_PCL and molecular weight of PEO. The Young's modulus and tensile strength of the porous films decreased, whereas the elongation‐at‐break increased with decreasing X_PCL. The enzymatic and alkaline hydrolysis rates of the porous films increased with a decrease in X_PCL and an increase in the molecular weight of PEO. The porous PCL films having Young's modulus in the range of 2–24 kg/mm² and enzymatic hydrolysis rate in the range of one‐ to 20‐fold that of the nonporous PCL film could be prepared by altering X_PCL and the molecular weight of PEO. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2281–2291, 2001     

Amylographic Reproducibility of Defatted Potato Starch by the Re-Introduction of Lipid

It was tried to get the amylographic reproducibility of the defatted potato starch by the re-addition of the extracted lipid fraction in order to increase the knowledge on starch-lipid interaction. The starch was defatted with methanol, dried and passed through a 100-mesh-sieve. Then, 1.0% fatty acid as sodium salt was re-introduced to the defatted starch. The surface lipids as well as the internal starch lipids affect several physico-chemical properties, and the defatting treatment influences the starch granules with respect to morphological and qualitative changes. From the results was concluded that the characteristics of amylographic alteration were caused by the internal starch lipids present in small, but significant amounts, together with the starch surface lipids. From the industrial point of view it seems to be of importance, that the defatting treatment of potato starch leads to more viscose starch pastes.     

Effect of temperature on the stability of various peptidases during peptide-enriched soy sauce fermentation

We previously developed a peptide-enriched soy sauce-like seasoning called Fermented Soybean Seasoning (FSS) with high-temperature fermentation, and we have reported the antihypertensive effects of FSS. Seryl-tyrosine (Ser-Tyr) and glycyl-tyrosine (Gly-Tyr) were identified from FSS as active constituents in the antihypertensive effects. They were found to be particularly enriched in FSS; more so than in regular soy sauce. In the present study, we clarified one of the mechanisms underlying the accumulation of these bioactive peptides during high temperature soy sauce brewing. Crude enzyme extracts were prepared from model soy sauce mash (moromi) fermented at various temperatures. Leucine aminopeptidase-I, II, and seryl-tyrosine hydrolytic activity were found to decrease in the moromi incubated at the fermentation temperature of FSS whereas almost no decrease was observed in that of regular soy sauce. The concentrations of ACE inhibitory peptides, Ser-Tyr and Gly-Tyr, in the moromi incubated at high temperature were revealed to be higher than those at low temperature through quantitative LC-MS/MS analysis. These results suggested that the peptidases responsible for degrading low molecular weight bioactive peptides were inactivated during the high temperature fermentation, thus, these peptides would be likely to remain in the high temperature fermentation.     

Tacticity of methacrylic copolymers and their crosslinked polymers studied by pyrolysis–gas chromatography

Diad tacticity of methyl methacrylate (MMA) sequences in the copolymers of MMA and various acrylates and their crosslinked polymers was characterized by pyrolysis–gas chromatography (Py‐GC) based on the relative peak intensities of the diastereomeric MMA tetramers in the pyrograms. The diad tacticity in the copolymers synthesized at a given temperature proved to be almost consistent with that of corresponding MMA homopolymers (PMMA) prepared under the same conditions. Furthermore, the diad tacticity of PMMAs was also consistent with that of the corresponding crosslinked polymers. These results suggest that the tacticity of MMA sequences in the polymer chains would be dominated by polymerization temperature, independent of the copolymerization and crosslinking. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 2140–2144, 2000     

Dill seed extract improves abnormalities in lipid metabolism through peroxisome proliferator‐activated receptor‐α (PPAR‐α) activation in diabetic obese mice

Dill, a small annual herb, is widely used as a flavoring agent in dishes including salads. It has been demonstrated that dill extract and its essential oil show hypolipidemic effects in rats. However, the mechanism of these effects has not been elucidated yet. We found that dill seed extract (DSE) activated peroxisome proliferator‐activated receptor‐α (PPAR‐α), an indispensable regulator for hepatic lipid metabolism, by luciferase assay. Thus, we performed DSE feeding experiments using diabetic obese model KK‐Ay mice to examine the effects of DSE on PPAR‐α activation in vivo. A 4‐week feeding of DSE contained in a high‐fat diet decreased plasma triacylglyceride and glucose levels and increased the mRNA expression levels of fatty acid oxidation‐related genes in the liver. In addition, the DSE feeding as well as bezafibrate (a PPAR‐α potent agonist) feeding increased oxygen consumption rate and rectal temperature. These results indicate that DSE suppresses high‐fat diet‐induced hyperlipidemia through hepatic PPAR‐α activation.     

Electrospinning processed nanofibrous TiO(2) membranes for photovoltaic applications

We have recently fabricated dye-sensitized solar cells (DSSCs) comprising nanofibrous TiO(2) membranes as electrode materials. A thin TiO(2) film was pre-deposited on fluorine doped tin oxide (FTO) coated conducting glass substrate by immersion in TiF(4) aqueous solution to reduce the electron back-transfer from FTO to the electrolyte. The composite polyvinyl acetate (PVac)/titania nanofibrous membranes can be deposited on the pre-deposited thin TiO(2) film coated FTO by electrospinning of a mixture of PVac and titanium isopropoxide in N,N-dimethylformamide (DMF). The nanofibrous TiO(2) membranes were obtained by calcining the electrospun composite nanofibres of PVac/titania as the precursor. Spectral sensitization of the nanofibrous TiO(2) membranes was carried out with a ruthenium (II) complex, cis-dithiocyanate-N,N(')-bis(2,2(')-bipyridyl-4,4(')-dicarboxylic acid) ruthenium (II) dihydrate. The results indicated that the photocurrent and conversion efficiency of electrodes can be increased with the addition of the pre-deposited TiO(2) film and the adhesion treatment using DMF. Additionally, the dye loading, photocurrent, and efficiency of the electrodes were gradually increased by increasing the average thickness of the nanofibrous TiO(2) membranes. The efficiency of the fibrous TiO(2) photoelectrode with the average membrane thickness of 3.9?μm has a maximum value of 4.14%.