Comparative study of soluble naphthalene diimide derivatives bearing long alkyl chains as n-type organic thin-film transistor materials

In this study, several naphthalene tetracarboxylic acid diimide (NTCDI) derivatives substituted at the N and N′ positions with long normal alkyl chains of different lengths were evaluated as soluble n-type organic thin-film transistor (TFT) materials. NTCDI derivatives with diundecyl (NTCDI-C11), didodecyl (NTCDI-C12), and ditridecyl (NTCDI-C13) exhibited acceptable solubility in chloroform, and their TFTs showed typical n-type TFT performance with relatively high field effect electron mobility (～0.2 cm²/V s) after annealing at a workable temperature of 150 °C. Although NTCDI with dioctyl (NTCDI-C8) showed good solubility in chloroform, the TFT performance of this material was highly inferior to that of NTCDI-C11, NTCDI-C12, or NTCDI-C13. We could not anneal NTCDI-C8 thin films at workable temperatures in vacuo because of sublimation of the material from the substrates. In contrast, NTCDI with dipentadecyl (NTCDI-C15) and dioctadecyl (NTCDI-C18) exhibited both poor solubility for chloroform and poor TFT performance. In short, these compounds are not suitable as soluble n-type organic TFT materials.     

Debates over dam removal in Japan

Japan is facing a severe problem with the aging of its infrastructure, including dams. We studied eight controversial cases (the Ararse, Okusawa, Setoishi, Tamayodo, Minochi, Yasuoka, Tsuga and Nibutani Dam) involving dam removal in Japan and elucidated the triggers and suggested reasons for the debate. Renewal of water rights was a major trigger in three of the eight cases. Environmental reasons in five cases were not relevant to the demolition decision regarding dams conferring public benefit, even if restoration of the river environment was a recognized benefit. Compared with single‐purpose dams, the removal debate for a multi‐purpose dam, based on economic reasons regarding a single function, did not gain traction. Among the eight cases, there has been no case triggered by the renewal of water right by reason of economics, which should be highlighted options for stock management purposes.     

Essential involvement of the Bacillus subtilis ABC transporter, EcsB, in genetic transformation of purified DNA but not native DNA from protoplast lysates

Involvement of the Bacillus subtilis ABC transporter EcsB in genetic transformation with native DNA from protoplast lysate (LP transformation) was investigated using an ecsB deletion mutant constructed by fusion polymerase chain reaction. In these experiments, the non-transformability phenotype of the ecsB mutant was reversed and high numbers of transformants generated (1.5 × 10⁵/μg DNA). The relative efficiency of transformation (RET) of ecsB to wild type (1.2 × 10^{− 2}) was a thousand times higher using native chromosomal DNA than the RET obtained from purified DNA (< 8.6 × 10^{− 6}). Similar transformation efficiencies were observed using native plasmid DNA. These results rule out a primary role for EcsB as a competence gene regulator. DNA-binding proteins attached to native DNA are not present in purified DNA preparations, and it is possible that such proteins could account for the transformability of the ecsB mutant. Because EcsB may play a role in protein(s) export, we tested exogenous proteins to identify functional replacements. We found that bovine serum albumin (fraction V) partially suppressed the phenotype of the ecsB mutation, leading to transformability with purified DNA. Linkage analysis of the ecsB mutant by LP co-transformation produced a higher co-transformation ratio (42% and 20%) at a distance of 34 kb and 121 kb in the ecsB mutant, compared to the wild-type strain, AYG2 (30.5% and 12.3%). The stimulatory linkage effect observed could be derived from a regulating gene involved in homologous recombination.     

Gain distribution measurement of an erbium-doped silica-based waveguide amplifier using a complex OLCR

We have measured the gain distributions of a 38-cm-long erbium-doped silica-based waveguide amplifier with different pump powers by using a complex optical low coherence reflectometer. The spatial resolution is /spl sim/5 mm and the noise level is /spl plusmn/1 dB. The measured distributions agree well with those derived from rate equations. We can estimate such amplifier parameters as the stimulated emission coefficient and the optimum waveguide length enabling us to achieve the maximum gain for any pump power.     

Design Guidelines of FRP Reinforced Concrete Building Structures

The “Design Guidelines of FRP Reinforced Concrete Building Structures” was established in 1993 as one of the final outputs of the research committee on fiber-reinforced plastic (FRP) reinforced concrete building structures organized under the Japanese Ministry of Construction's research and development project titled: “Effective Use of Advanced Construction Materials (1988–92).” These Guidelines are a translation of the Japanese guidelines. They describe the design concept for nonprestressed concrete structures reinforced with FRP rebars, and the calculation equations are all relegated to the commentaries due to lack of design data on FRP reinforced concrete structures. A limit-state design method has been adopted under the guidelines. Among the subjects covered are overview, design method, materials, loads and combination, stress and deformation, ultimate state design, serviceability state design, structural requirement, and testing methods for the tensile strength and bond strength of materials. “The Design Guidelines for FRP Prestressed Concrete Members” is separate from these guidelines.     

Seasonal profiles of human noroviruses and indicator bacteria in a wastewater treatment plant in Tokyo, Japan.

The seasonal profiles of microorganisms in raw sewage, secondary-treated sewage, and final effluent at a wastewater treatment plant in Tokyo, Japan, were quantitatively determined each month for one year, from July 2003 to June 2004. Human noroviruses, which were determined by real-time PCR, in raw sewage varied from 0.17-260 copies/mL for genotype 1 and from 2.4-1900 copies/mL for genotype 2, showing much higher values in winter, the epidemic season. The concentration of total coliforms, Escherichia coli, or F-specific phages in raw sewage was almost constant throughout the year. Human noroviruses of genotype 2 were removed most effectively (3.69 log10 on average) at the wastewater treatment plant, followed by E. coli (3.37 log10), total coliforms (3.05 loglo), F-specific phages (2.81 log10), and human noroviruses of genotype 1 (2.27 log10). The removal ratio of human noroviruses was almost constant, independent of the initial concentration of the viruses in raw sewage, which led to the increasing concentration of human noroviruses in final effluent in winter. None of the tested bacteria was judged to be a reliable indicator of human noroviruses in final effluent.     

Reversible Control of Exo‐ and Endo‐Budding Transitions in a Photosensitive Lipid Membrane

We have developed a method for the photomanipulation of lipid membrane morphology in which the shape of a vesicle can be switched by light through the use of a synthetic photosensitive amphiphile containing an azobenzene unit (KAON12). We prepared cell‐sized liposomes from KAON12 and 1,2‐dioleoyl‐sn‐glycero‐3‐phosphocholine (DOPC) and conducted real‐time observations of vesicular transformation in the photosensitive liposome by phase‐contrast microscopy. Budding transitions—either budding toward the centre of the liposome (endo‐bud) or budding out of the liposome (exo‐bud)—could be controlled by light. We discuss the mechanism of this transformation in terms of the change in the effective membrane surface area due to photoisomerization of the constituent molecules.