Vol. 42, No. 1, pp.16-21, 2008Decrease in the skin transparency induced by protein carbonylation in the stratum corneum

It has been reported in recent years that the carbonyl modification of protein plays a part in various diseases. The existence of the protein carbonylation in the stratum corneum also came to be known in the last few years, but the effect on the properties of the stratum corneum including the skin appearance was not clarified. In this study, we examined the influence of protein carbonylation in the stratum corneum to provide helpful information for skin care products focusing on transparency of the stratum corneum. Firstly, we developed a method to assess the protein carbonylation level numerically by the image analysis of tape-stripped stratum corneum reacted with a fluorescent hydrazide. The level of stratum corneum carbonylation of the sun-exposed site (face) was higher than that of unexposed site (upper arm), and the surface part of the stratum corneum showed a higher level of carbonylation compared with the deeper layer. Stratum corneum carbonylation was induced by in vitro UV irradiation. In addition, it was shown that the skin transparency score was significantly low in the woman with high level of protein carbonylation in the stratum corneum of the cheek. An experimentally carbonylated stratum corneum sheet in vitro became opaque. Among the amino acids investigated, L-lysine was the most effective to prevent carbonylation of the stratum corneum ex vivo . Moreover, L-lysine inhibited the decrease in the skin transparency caused by experimental carbonylation of the stratum corneum in the human skin. These results suggest that preventing the carbonylation of the stratum corneum due to adverse effects from the environment by l-lysine could improve the skin transparency.
Keywords: stratum corneum, protein carbonylation, appearance, skin transparency, l-lysine, amino acids, fluorescent hydrazide, tape-stripping     

Semiconductor-sensitized solar cells based on nanocrystalline In2S3/In2O3 thin film electrodes

A possibility of semiconductor-sensitized thin film solar cells have been proposed. Nanocrystalline In₂S₃-modified In₂O₃ electrodes were prepared with sulfidation of In₂O₃ thin film electrodes under H₂S atmosphere. The band gap (E_g) of In₂S₃ estimated from the onset of the absorption spectrum was approximately 2.0 eV. The photovoltaic properties of a photoelectrochemical solar cell based on In₂S₃/In₂O₃ thin film electrodes and I⁻/I₃⁻ redox electrolytes were investigated. This photoelectrochemical cell could convert visible light of 400–700 nm to electron. A highly efficient incident photon-to-electron conversion efficiency (IPCE) of 33% was obtained at 410 nm. The solar energy conversion efficiency, η, under AM 1.5 (100 mW cm⁻²) was 0.31% with a short-circuit photocurrent density (J_sc) of 3.10 mA cm⁻², a open-circuit photovoltage (V_oc) of 0.26 V, and a fill factor ( ff ) of 0.38.     

Novel isoflavone diglycoside in groundnut (Apios americana Medik)

In the present HPLC-based analysis of the isoflavone profile of groundnut (Apios americana Medik) tubers, we identified a major peak that did not correspond to any known isoflavones. A water extract of groundnut tubers prepared at 4 °C showed the major and genistin peaks, whereas that prepared at 45 °C did not yield these peaks but showed a peak for genistein on HPLC analysis. When the extract was treated with β-glucosidase after the inactivation of endogenous enzymes, the major peak decreased over time and the genistin peak also decreased after a transient increase, changes which were accompanied by the appearance of a genistein peak. The HPLC elution pattern of the β-glucosidase-treated extract was markedly similar to that observed for the extract prepared at 45 °C.     

One ether-functionalized guanidinium ionic liquid as new electrolyte for lithium battery

One ether-functionalized guanidinium ionic liquid is used as new electrolytes for lithium battery. Viscosity, conductivity, behavior of lithium redox, chemical stability against lithium metal, and charge-discharge characteristics of lithium batteries, are investigated for the IL electrolytes with different concentrations of lithium salt. Though the cathodic limiting potential of the IL are 0.7 V vs. Li/Li⁺, the lithium plating and striping on Ni electrode can be observed in the IL electrolytes, and the IL electrolytes show good chemical stability against lithium metal. Li/LiCoO₂ cells using the IL electrolytes without additives have good capacity and cycle property at the current rate of 0.2 C when the LiTFSI concentration is higher than 0.3 mol kg⁻¹, and the cell using the IL electrolyte with 0.75 mol kg⁻¹ LiTFSI owns good rate property. The activation energies of the LiCoO₂ electrode for lithium intercalation are estimated, and help to analyze the factors determining the rate property.     

Increase in pladienolide D production rate using a Streptomyces strain overexpressing a cytochrome P450 gene

Pladienolide B and its 16-hydroxylated derivative (pladienolide D) are novel 12-membered macrolides produced by Streptomyces platensis Mer-11107 showing strong in vitro and in vivo antitumor activity. While pladienolide B is mainly produced by this strain, pladienolide D is produced to a lesser extent. To facilitate the production of pladienolide D by biotransformation, we found that Streptomyces bungoensis A-1544 was able to hydroxylate pladienolide B at 16-position. We identified psmA from S. bungoensis A-1544, which encoded a pladienolide B 16-hydroxylase PsmA belonging to the CYP105 family of cytochrome P450. To increase the efficiency of pladienolide D production, we constructed recombinant S. bungoensis A-1544 overexpressing psmA and performed biotransformation of pladienolide B to pladienolide D. This biotransformation achieved a production level 15-fold higher than that using the control strain S. bungoensis A-1544/pIJ702.     

Analysis of generated power of ETS-VII during solar activity maximum period

The generated power degradation of a satellite in a low earth orbit during high solar activity period has been compared with the power degradation of a satellite during low solar activity period. A degradation prediction method is developed for this study. As a result, the effect of a large solar flare on solar cell degradation is found to be negligible in a low earth orbit. This is because the effects of shield thickness and inclination are thought to be greater than that of degrees of solar activity.     

Planate conducting polymer actuator based on polypyrrole and its application

In this study, we propose a planate actuator which can transform only its central part locally. We have developed a planate conducting polymer actuator based on polypyrrole (PPy) and two types of acids, such as p-phenol sulfonic acid and dodecylbenzene sulfonic acid, by electrodeposition. Its structure was patterned bimorph structure with anion-driven, cation-driven and bimorph layers. The planate conducting polymer actuator could deform only its central part locally. Moreover, we introduce a micro-pump that operates by planate conducting polymer actuator as the drive source. The water level in the flow channel of micro-pump shows the reciprocating motion measuring ±2 mm in accordance with the oscillation of the bimorph conducting polymer actuator which was approximately 28 μl/min. The oscillating volume can be controlled by the application of electrochemical potential and its scan rate applied to the actuator.