Sol–Gel‐Derived High‐Performance Stacked Transparent Conductive Oxide Thin Films

Single‐ and multi‐layer transparent conductive oxide (TCO) thin films exhibiting high performance, good packing density and low surface/interface roughness are deposited on silica glass substrates by the sol–gel method. The crystal and microstructural properties of the TCO thin films are evaluated as an alternate to films prepared by ultra‐high vacuum deposition. Tin‐doped indium oxide (ITO) thin films produced using a two‐step drying process showed low surface roughness because of dense packing structure not only horizontal but also vertical directions. As a result, electrical conductivity, carrier concentration, carrier mobility, and optical transmittance of 2.3 × 10³ S/cm, 8 × 10²⁰ cm^?3, 18 cm²/Vs, and over 98% at 500 nm, respectively, were achieved. A multilayer ZnO/ITO stacked structure was also fabricated using the sol–gel process. Our findings suggest that solution‐based methods show promise as an alternative to existing ultra‐high vacuum methods to fabricate TCO thin films.     

Albumin stabilizes (–)‐epigallocatechin gallate in human serum: Binding capacity and antioxidant property

(–)‐Epigallocatechin gallate (EGCg) is the major component of green tea and is known to show strong biological activity, although it can be easily oxidized under physiological conditions. In this study, we indicate that EGCg is stable in human serum and that human serum albumin (HSA) stabilizes EGCg under aerobic condition. Although EGCg is usually decomposed within 1 h in aqueous solution at neutral pH, EGCg in serum and phosphate buffer (pH 7.4) containing HSA was stable over 1 h, even at neutral and slightly alkaline pH. Under these conditions, EGCg binds to HSA non‐covalently. The sulfhydryl group acts as an antioxidant for EGCg oxidation. Incubation of EGCg with HSA is accompanied by the oxidation of a free sulfhydryl group in HSA. These results suggest that the antioxidant property and the binding capacity of HSA contribute to the stabilization of EGCg in human serum.     

Preparation of highly dispersed gold nanoparticles inside the porous support assisted by amphiphilic vinyl maleate copolymer

An amphiphilic copolymer composed of maleic acid and alkyl (C₁₈) vinyl monomer was encapsulated into the porous support. A series of colloidal gold nanoparticles of known size was substantially immobilized in the composite porous supports based on cross-linked polyacrylate ester and cross-linked polystyrene resin. Maleic acid moiety of the amphiphilic copolymer can act as a stabilizer for gold nanoparticles in analogy to citric acid, whereas alkyl chains play a role for the stable accommodation of the amphiphilic copolymer. Maleic acid stabilizes the gold nanoparticles by flexing the geometrical arrangement of the linear polymer. Presence of C₁₈ alkyl chain in the poly(C₁₈-vinyl maleate) is indispensable to act as spacing group that prevents mutual aggregation of gold nanoparticles. On the other hand, gold nanoparticles with average diameter of less than 8 nm were spontaneously formed by treatment of the composite resin beads with aqueous HAuCl₄ solution, subsequently dispersed inside the pores of resin beads as observed by TEM. We have also elucidated the catalytic activity of the material with the hydrogenation of cinnamaldehyde in supercritical carbon dioxide. Notably, apparent size effect of gold was observed in the selectivity of the reaction.     

Estimation of concentrations of antifungal agents allowed as food additives in foods and their daily intake based on official inspection results in Japan in fiscal year 1998

The mean concentrations and daily intake of four antifungal agents were estimated based on the results of an analysis of 7,005 samples of food obtained in official inspections by Japanese local governments in fiscal year 1998. The mean concentration of diphenyl was 0.0004% of the allowable limit, and those of imazalil, o-phenylphenol, and thiabendazole were 14.0%, 3.5%, and 5.7%, respectively. The daily intakes of these antifungal agents per person, estimated from their concentrations and the daily consumption of the foods, were 0.000326, 1.89, 11.5, and 23.3 micrograms, respectively, and assuming a body weight of 50 kg, the amounts of these antifungal agents consumed were 0.000013%, 0.15%, 0.12%, and 0.47% of the acceptable daily intake, respectively. These values are similar to the values obtained on the basis of the results of the official inspection in fiscal years 1994 and 1996, except that the amount of diphenyl is much lower (1/100).     

DNA taken into Bacillus subtilis competent cells by lysed-protoplast transformation is not ssDNA but dsDNA

Competent Bacillus subtilis incorporates whole-genome DNA (4215 kb) from the protoplast lysate of B. subtilis subtilis [Akamatsu, T. and Taguchi, H., Biosci. Biotechnol. Biochem., 65, 823-829 (2001)]. A continuous incorporated DNA is longer than 1500 kb [J. Biosci. Bioeng., 101, 257-262 (2006)]. Whether the incorporated DNA is single-stranded (ssDNA) or double-stranded DNA (dsDNA) has been studied by examining the transforming activity of the incorporated DNA. B. subtilis BEST7027 was used as the donor strain, which has a heterologous region consisting of the 145 kb region of the Synechocystis sp. PCC6803 genome and erm gene. The donor DNA was transferred to a wild-type or a recA recipient strain (AYG2 or SYN9), and protoplast lysate was prepared from the transformants and used as the donor DNA source for the second recipient strain (AU1 or AV1). The intergenote region showed a significant transforming activity. When DNase I was added to both cells collected from the first transformation mixture and the following protoplastization, the result was similar to that obtained without DNase I. All of the observations strongly suggest that the incorporated DNA is dsDNA, and the transformation of competent B. subtilis by DNA in protoplast lysate is different from that by purified DNA taken up conventionally.     

Effect of culture conditions of acetic acid bacteria on cellulose biosynthesis

An attempt was made to clarify the effect of culture conditions of an acetic acid bacteria (Acetobacter xylinum) on cellulose biosynthesis using glucose as carbon source in complex medium. Synchronous culture conditions were first realised on cellulose biosynthesis by cooling the system to 4°C for 24 h. Under the synchronous conditions stepwise division of the cell and the stepwise production of cellulose were found. Furthermore, cellulose was proved to be produced when the cell number in the medium was constant.     

Risk of cancer and non-cancer diseases in the atomic bomb survivors

Late health effects of exposure to atomic bomb radiation have been evaluated in survivors. A cohort of 120 321 people has been followed since 1950 for mortality, including the cause of death using the Japanese population registry system (Life Span Study), and for cancer incidence using population-based cancer registries. Findings have included a markedly increased risk of leukaemia several years after the exposure, increased risk of various malignant tumours several decades after the exposure and, more recently, findings of increased rates of non-cancer diseases such as cardiovascular diseases.