Design of a dual‐input SC DC–DC converter realizing negative outputs

Aimed at a back‐lighting application, a dual‐input switched‐capacitor (SC) DC–DC converter with battery charge process is proposed in this paper. The proposed converter can realize −1/N× (N = 2,3,…) step‐down conversion as well as (N + 1)/N× step‐up conversion. By converting clean energy such as solar energy, the proposed dual‐input converter not only drives light‐emitting diodes (LEDs) but also recharges the battery, although conventional single‐input converter only consumes battery energy. In the proposed converter, the −1/N× stepped‐down voltage is generated to drive the LED's cathode when the input voltage is insufficient to drive a 1× transfer mode. Furthermore, unlike conventional converters, the battery is charged by the (N + 1)/N× stepped‐up voltage when the LED back light is in standby mode. Hence, the proposed converter can realize long battery run time. The validity of circuit design is confirmed by theoretical analyses, simulations, and experiments. The derived theoretical formulas will be helpful to estimate circuit characteristics, because the theoretical results correspond well with the simulation program with integrated circuit emphasis (SPICE) simulation results. © 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

鞋材料革的卫生研究

我们在鞋内卫生方面完成了系统研究，并注明了条件。本文中，我们报导了湿气的累积和微生物的生长取决于鞋的不同材料。我们得出结论，鞋的用料和结构对累积湿气和它对微生物环境的影响方面是最重要的卫生因素。     

Efficient DNA strand displacement by a W-shaped nucleoside analogue (WNA-βT) containing an ortho-methyl-substituted phenyl ring

Molecules that can target duplex DNA with sequence selectivity have the potential to be useful tools in genomic research and also as therapeutic agents. Homopurine-homopyrimidine stretches in duplex DNA can be recognized by homopurine or homopyrimidine TFOs (triplex-forming oligonucleotides) through the formation of triplex DNA. We have previously developed bicyclic nucleoside analogues (WNAs) for the formation of stable triplexes in the formation of stable antiparallel triplexes containing a TA or a CG interrupting site. In this study, we investigated the effects on triplex DNA formation of ortho-, meta-, and para-methyl substituent groups on the aromatic ring of the WNA analogue. It was found that the homopurine TFO containing meta- and para-methyl-substituted WNA-βT (mMe-WNA-βT, pMe-WNA-βT) stabilized triplexes containing a TA interrupting site or a GC site, respectively. Interestingly, the ortho-methyl-substituted WNA-βT (oMe-WNA-βT) efficiently promoted DNA strand displacement to form the TFO/pyrimidine duplex. A detailed investigation showed that the duplex was in the antiparallel orientation and that its formation took place prior to triplex formation with the need for a magnesium cation. NOESY measurements indicated a significant difference in the rotation flexibilities of the phenyl rings of WNA-βTs: that is, the conformation of the ortho-methylated phenyl ring was stable in a temperature-independent manner. It was speculated that the initial formation of a ternary complex was followed by strand displacement and then the formation of the TFO/pyrimidine duplex together with the TFO(2)/pyrimidine triplex formation during the early stage, and that the equilibrium shifted to the triplex during the later stage. Although the detailed role is still uncertain, the fixed phenyl ring of oMe-WNA-βT might play a role in the displacement reaction.     

Curing of epoxy siloxane monomer with anhydride

Epoxy siloxane monomer, 1,3‐Bis[2‐(3‐{7‐oxabicyclo[4.1.0]heptyl})ethyl]‐tetramethyldisiloxane, was cured with methylhexahydrophthalic anhydride, and the catalysts, N,N‐dimethylbenzylamine (BDMA) and tetra‐n‐butylphosphonium o,o‐diethylphosphorodithioate (PX‐4ET), were compared. The curing reactivity of BDMA was higher than that of PX‐4ET, but the thermal stability of the polymer was lower. PX‐4ET caused less thermal discoloration, which increased in proportion to catalyst concentration. The optimum was 0.71–0.35 mol %. Maximum hardness and glass transition temperature as well as minimum coefficient of thermal expansion and thermal discoloration was achieved with equivalent amounts of epoxy and anhydride. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 946–951, 2005     

Comparative Studies of the Ability of Males to Discriminate Between Sexes in Caloglyphus spp.

Female sex pheromones that trigger the mounting behavior of conspecific males have been identified in four species of the genus Caloglyphus—C. polyphyllae, C. rodriguezi, and two unidentified species. Although the sex pheromones are distributed over both males and females, content ratios of female to male vary from 1.4 in Caloglyphus sp. MJ to 3.4 in C. polyphyllae, 6.3 in C. rodriguezi, and 8.4 in Caloglyphus sp. HP. In the former two species the sex pheromones are also detectable in nymphal stages as a major component, while the pheromones are found to be adult specific in the latter two species. Evaluation of the ability of males to recognize conspecific females revealed that males of all three species, except the Caloglyphus sp. MJ, could discriminate between females and males. We conclude that the differences in the amounts of the female sex pheromone function to facilitate in discrimination by males of conspecific females in the three species, while males of Caloglyphus sp. MJ cannot do this because the 1.4-fold difference is insufficient. It is suggested that the sex pheromone of Caloglyphus spp. might have evolved from a common compound, which originally functioned as a male sexual excitant, into the sex-specific compound that now functions to allow males to discriminate females from males.     

Acyltransferase Domain Exchange between Two Independent Type I Polyketide Synthases in the Same Producer Strain of Macrolide Antibiotics

Streptomyces graminofaciens A-8890 produces two macrolide antibiotics, FD-891 and virustomycin A, both of which show significant biological activity. In this study, we identified the virustomycin A biosynthetic gene cluster, which encodes type I polyketide synthases (PKSs), ethylmalonyl-CoA biosynthetic enzymes, methoxymalony-acyl carrier protein biosynthetic enzymes, and post-PKS modification enzymes. Next, we demonstrated that the acyltransferase domain can be exchanged between the Vsm PKSs and the PKSs involved in FD-891 biosynthesis (Gfs PKSs), without any supply problems of the unique extender units. We exchanged the malonyltransferase domain in the loading module of Gfs PKS with the ethylmalonyltransferase domain and the methoxymalonyltransferase domain of Vsm PKSs. Consequently, the expected two-carbon-elongated analog 26-ethyl-FD-891 was successfully produced with a titer comparable to FD-891 production by the wild type; however, exchange with the methoxymalonyltransferase domain did not produce any FD-891 analogs. Furthermore, 26-ethyl-FD-891 showed potent cytotoxic activity against HeLa cells, like natural FD-891.     

Colorimetric sensing of H2PO4− using a Pb2+ complex of a pyridylazo dye in aqueous solution

This study develops a sensitive and selective colorimetric probe for the detection of dihydrogen phosphate (H₂PO₄⁻) based on a lead ion (Pb²⁺) complex of a commercially available pyridylazo dye (PAPS) in aqueous media under physiological conditions. The complex was made by adding Pb²⁺ to PAPS in a 1:1 stoichiometric ratio (PAPS-Pb²⁺), which was accompanied by the remarkable solution change from yellow to purple. The colorimetric sensing of H₂PO₄⁻ over other anions with PAPS-Pb²⁺ occurred owing to the regeneration of original PAPS by the interaction of H₂PO₄⁻ with Pb²⁺ in a 1:2 molar ratio. Moreover, the H₂PO₄⁻ detection was less affected by the presence of other coexisting competitive anions. The colorimetric naked-eye behaviour of PAPS-Pb²⁺ rendered a useful and convenient probe for the detection of H₂PO₄⁻ via the indicator displacement assay.