Control over wettability of textured surfaces by electrospray deposition

Microtextured surfaces were prepared by electrospray deposition (ESD) from hydrophilic and hydrophobic acrylic resin solutions. The surface morphologies and topologies were characterized using scanning electron microscopy and laser profile microscopy, respectively. Wetting behaviors on the surfaces were characterized by contact angle and sliding angle measurements. The contact angle of the water droplet on the hydrophilic resin‐coated surfaces decreased with an increase in the surface roughness. On the other hand, the contact angle on the hydrophobic resin‐coated surfaces increased with an increase in the surface roughness. In addition, a patterned surface composed of aligned fibers by ESD showed anisotropy of both wetting and sliding behaviors. These results indicate that ESD is a useful method for designing a textured surfaces and controlling the surface wettability. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3811–3817, 2007     

Using promoter replacement and selection for loss of heterozygosity to generate an industrially applicable sake yeast strain that homozygously overproduces isoamyl acetate

By application of the high-efficiency loss of heterozygosity (HELOH) method for disrupting genes in diploid sake yeast (Kotaka et al., Appl. Microbiol. Biotechnol., 82, 387–395 (2009)), we constructed, from a heterozygous integrant, a homozygous diploid that overexpresses the alcohol acetyltransferase gene ATF2 from the SED1 promoter, without the need for sporulation and mating. Under the conditions of sake brewing, the homozygous integrant produced 1.4 times more isoamyl acetate than the parental, heterozygous strain. Furthermore, the homozygous integrant was more genetically stable than the heterozygous recombinant. Thus, the HELOH method can produce homozygous, recombinant sake yeast that is ready to be grown on an industrial scale using the well-established procedures of sake brewing. The HELOH method, therefore, facilitates genetic modification of this rarely sporulating diploid yeast strain while maintaining those characteristics required for industrial applications.     

Adaptation of a thermophilic enzyme, 3-isopropylmalate dehydrogenase, to low temperatures

Random mutagenesis coupled with screening of the active enzymeat a low temperature was applied to isolate cold-adapted mutantsof a thermophilic enzyme. Four mutant enzymes with enhancedspecific activities (up to 4.1-fold at 40°C) at a moderatetemperature were isolated from randomly mutated Thermus thermophilus3-isopropylmalate dehydrogenase. Kinetic analysis revealed twotypes of cold-adapted mutants, i.e. k_cat-improved and K_m-improvedtypes. The k_cat-improved mutants showed less temperature-dependentcatalytic properties, resulting in improvement of k_cat (up to7.5-fold at 40°C) at lower temperatures with increased K_mvalues mainly for NAD. The K_m-improved enzyme showed higheraffinities toward the substrate and the coenzyme without significantchange in k_cat at the temperatures investigated (30–70°C).In k_cat-improved mutants, replacement of a residue was foundnear the binding pocket for the adenine portion of NAD. Twoof the mutants retained thermal stability indistinguishablefrom the wild-type enzyme. Extreme thermal stability of thethermophilic enzyme is not necessarily decreased to improvethe catalytic function at lower temperatures. The present strategyprovides a powerful tool for obtaining active mutant enzymesat lower temperatures. The results also indicate that it ispossible to obtain cold-adapted mutant enzymes with high thermalstability.     

Evaluation of grain boundary embrittlement of phosphorus added F82H steel by SSTT

Non-hardening embrittlement (NHE) can be happened by a large amount of He on grain boundaries over 500–700 appm of bulk He without hardening at fusion reactor condition. Especially, at high irradiation temperatures (>≈420 °C), NHE accompanied by intergranular fracture affects the severe accident and the safety of fusion blanket system. Small specimen tests to evaluate fracture toughness and Charpy impact properties were carried out for F82H steels with different levels of phosphorous addition in order to simulate the effects of NHE on the shift of transition curve. It was found that the ductile to brittle transition temperature (DBTT) and reference temperature (T₀) after phosphorous addition is shifted to higher temperatures and accompanied by intergranular fracture at transition temperatures region. The master curve approach for evaluation of fracture toughness change by the degradation of grain boundary strength was carried out by referring to the ASTM E1921.     

Screening of depressive tendency in children by evaluating facial expression cognition

These days suicides are being committed by students at all three levels of schooling. This serious problem is one that we should respond to as quickly as possible. Pediatric depression is a potential source of this problem. Previously, we have reported a simple diagnosis of the depressed state using facial expression cognition in the case of adults. There we implemented a self‐diagnostic inspection that can be carried out easily in a short time for the screening of depression. In this report, we examine whether the method we developed for adults may be applied to children as a fast and effective response to the big problem of pediatric depression. Through this examination, we hope that we can respond quickly to the problem of suicides by students in schools at all three levels caused by depression. Moreover, we can respond to a situation in which the school and parents do not understand the children's mental state that contributes heavily to these acts. From this response, we can evolve a better support system. Furthermore, we examine an application that uses a hand phone to improve the early stages of detection and evolve a support system through the increased number of users. Copyright © 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

PCR-mediated seamless gene deletion and marker recycling in Saccharomyces cerevisiae

Repeated gene manipulations can be performed in yeast by excision of an introduced marker. Cassette modules containing a marker flanked by two direct repeat sequences of hisG or loxP have often been used for marker recycling, but these leave one copy of the repeats in the chromosome after excision. Genomic copies of a repeat can cause increased mistargeting of constructs containing the same repeats or unexpected chromosomal rearrangements via intra- or interchromosomal recombinations. Here, we describe a novel marker recycling procedure that leaves no scar in the genome, which we have designated seamless gene deletion. A 40 base sequence derived from an adjacent region to the targeted locus was placed in an integrating construct to generate direct repeats after integration. Seamless HIS3 deletion was achieved via a PCR fragment that consisted of a URA3 marker attached to a 40 base repeat-generating sequence flanked by HIS3 targeting sequences at both ends. Transformation of the designed construct resulted in his3 disruption and the generation of 40 base direct repeats on both sides of URA3 in the targeted locus. The resulting his3::URA3 disruptants were plated on 5-fluoroorotic acid medium to select for URA3 loss. All the selected colonies had lost URA3 precisely by recombination between the repeats, resulting in his3 deletion without any extraneous sequences left behind in the chromosome.     

Simulation of nanostructure production by electromigration considering specimen's shape

Al nanowires have been successfully formed utilizing electromigration in the passivated Al thin film specimen. A numerical simulation of the nanostructure production method was recently developed based on the governing parameter for electromigration damage. The results of the simulation were verified through experiment. It was shown that this procedure predicted the nanostructure volume formed during lifetime of the specimen, though the nanostructure formation was influenced by the current density and substrate temperature. In this study, the method is applied to Al specimens with various shapes to devote to the theoretical discussion on the efficient production of nanostructure. It is found that volume of the formed nanostructure depends on shape of the specimen. The shape affects distributions of current density, temperature and atomic density in the specimen, so formation speed, lifetime and consequently nanostructure volume during the lifetime are changed. It is clarified that this simulation method will contribute to seeking the optimum specimen's shape for efficient NS production.     

NOX reduction over paper-structured fiber composites impregnated with Pt/Al2O3 catalyst for exhaust gas purification

Pt/Al₂O₃ catalyst powder was successfully incorporated in a microstructured paper-like matrix composed of a ceramic fiber network, by use of a simple papermaking technique. As-prepared composite, denoted paper-structured catalyst, was applied to the reduction of nitrogen oxide (NO _X ) in the presence of propene, for exhaust gas purification. The paper-structured catalyst demonstrated higher NO _X reduction efficiency and more rapid thermal responsiveness than a conventional Pt-loaded honeycomb catalyst, indicating that the paper-like structure with interconnected pore spaces contributes to effective transport of heat and reactants to the catalyst surfaces. Furthermore, the paper-structured catalyst with the appearance of flexible paperboard has a high degree of utility. The efficiency of utilization of Pt catalyst was improved by using hierarchically assembled paper-structured catalysts with preferential location of Pt catalyst in the upper part. The paper-structured catalyst composite with paper-like utility and porous microstructure is thought to be a promising catalytic material for efficient NO _X gas purification.     

Thermal lens micro optical systems

This paper describes two types of miniaturized thermal lens optical systems that use optical fibers, SELFOC microlenses and light sources. The first system consists of a compact diode pumped solid-state laser (532 nm) as an excitation light source, a laser diode (635 nm) as a probe light source, an acoustoptic modulator as an excitation light modulator, fiber-based and conventional optics, and a detection system that combines a pinhole, an interference filter, and a photodiode. The second system consists of two laser diodes as the excitation (658 nm) and probe (780 nm) light sources, fiber-based optics, and the same detection system as the first one. The performance of the two systems was evaluated by the limit of detection (LOD) using standard solutions of sunset yellow (SY) and nickel(II) phthalocyaninetetrasulfonic acid tetrasodium salt (NiP). The LODs of the first system for SY and second system for NiP were calculated to be 3.7 x 10(-8) (1.7 x 10(-6) AU) and 7.7 x 10(-9) M (3.4 x10(-6) AU), respectively. These results were consistent with the expected values obtained from photothermal parameters.