Male-Released Sex Pheromone of the Stink Bug Piezodorus hybneri

Male-released semiochemicals of the stink bug Piezodorus hybneri (Heteroptera: Pentatomidae) elicit attraction of male and female bugs and homosexual behavior in males. Three active components were isolated from the airborne volatiles of males by flash chromatography, with the activity monitored by GC-EAD and behavioral bioassay. The pheromone system was characterized as a mixture of -sesquiphellandrene, (R)-15-hexadecanolide, and methyl 8-(Z)-hexadecenoate (ratio: 10:4:1), and the activity of the semiochemicals was assessed with authentic samples. Enantiomerically pure samples of the R and S macrolactones were obtained by Yamaguchi's and Mitsunobu's macrolactonization of a key intermediate, (R)-15-hydroxyhexadecanoic acid. The nonnatural S stereoisomer was neither a beneficial nor a behavioral antagonist. Individual constituents or binary mixtures were active, but the optimal male response was elicited only by the full mixture. Behavioral observation and the fact that the onset of pheromone production is coincident with ovarian development strongly suggest that these semiochemicals are, in fact, sex pheromones.     

Development of snake-like robot ACM-R8 with large and mono-tread wheel

One of the important advantages of an active wheeled snake-like robots is that it can access narrow spaces which are inaccessible to other types of robot (such as crawlers, walking robots), since snake-like robots have an elongated, narrow body. Additionally, in areas with rubble, snake-like robots can traverse rough terrain and large obstacles since its body can conform to the terrain’s contours. ‘ACM-R8’ is a new snake-like robot which can climb stairs and reach doorknobs in addition to the features explained above. To fulfill these functions, the design of this robot incorporates several key features: joints with parallel link mechanism, mono-tread wheels with internal structure, force sensors and ‘swing-grousers’ which were developed to improve step climbability. In this paper, the design and control methods are described. Experiments confirmed high mobility on stairs and steps, with the robot succeeding in overcoming a step height of 600 mm, despite the height of the robot being just 300 mm.     

Narrow‐gap field‐sequential TN‐LCD with and without nanoparticle doping

Abstract— The fabrication and demonstration of field‐sequential‐color (FSC) LCDs using modules of narrow‐gap twisted‐nematic (NTN) LCDs with and without doping of newly synthesized PγCyD‐ZrO² nanoparticles is reported. Two types of FSC‐LCDs are demonstrated: one is a direct multiplexed NTN‐LCD and the other is TFT driven. The advantages of FSC‐LCDs include their high legibility even under direct sunlight, and the mechanism for the doping of nanoparticles in LCDs is discussed.     

Biodegradable Porous Microneedles for an Electric Skin Patch

An array of porous microneedles (PMNs) made of biodegradable poly(lactic-co-glycolic acid) (PLGA) is fabricated by a combination of molding and freeze-drying methods. The optimized mixture of PLGA and 1,4-dioxane is poured into a mold of a microneedle array, followed by the freezing and sublimation of the frozen particles of 1,4-dioxane, a procedure that left an interconnecting porous structure in the PLGA with a porosity around 50%. The mechanical strength of the PMN made of PLGA (PLGA-PMN) is reinforced by modification with carboxymethylcellulose (CMC), resulting in sufficient strength enough for insertion into an excised porcine skin. The transdermal resistance is significantly decreased by the CMC-modified PLGA-PMN, which would improve the efficiency and safety of DC current-based transdermal techniques, including the electrical monitoring of the skin condition and iontophoresis for drug delivery and medical diagnosis.     

Alcohol oxidase hybrid oligomers formed in vivo and in vitro

Cell‐free extract prepared from methanol‐grown cells of the methylotrophic yeast Pichia methanolica showed nine multiple alcohol oxidase (AOD) bands on active staining in native polyacrylamide gel electrophoresis. Their molecular basis was investigated and two AOD‐encoding genes, MOD1 and MOD2, were cloned from P. methanolica genome. When the two genes were expressed in a heterologous host, an alcohol oxidase‐depleted strain of Candida boidinii(aod1Δ strain), both MOD1 and MOD2 partially complemented growth defect of the host strain on methanol. While expression of either MOD1 or MOD2 in C. boidinii aod1Δ strain gave a single AOD band corresponding to the band with the largest and smallest mobility among the nine AOD bands, respectively, co‐expression of MOD1 and MOD2 resulted in multiple band formation. Mixed oligomerization of Mod1p and Mod2p in vitro also gave nine multiple bands. From these results, we concluded that the nine multiple forms of AOD observed on native–PAGE represent two homo‐octamers and seven hetero‐octamers of Mod1p and Mod2p. Using this zymogram analysis, we also found that Mod1p was preferably produced at low methanol concentrations in the media, while Mod2p was produced at higher methanol concentrations. This shows distinct regulatory features of the two AOD‐encoding genes in this methylotrophic yeast. Copyright © 1999 John Wiley & Sons, Ltd.     

Growth of homogeneous polycrystalline Si1-xGex and Mg2Si1-xGex for thermoelectric application

Homogeneous polycrystalline Si_1-xGe_x were grown using a Si(seed)/Ge/Si(feed) sandwich structure under the low temperature gradient less than 0.4 °C/mm. It was found that the composition of the Si_1-xGe_x was controlled by the growth temperature. The homogeneous Mg₂Si_1-xGe_x was synthesized by heat treatment of the homogeneous Si_1-xGe_x powders under Mg vapor. The Mg₂Si_1-xGe_x sample with the relative density of 95% was synthesized by spark plasma sintering technique. The resistivity and the Seebeck coefficient of the Si, Ge, Si_1-xGe_x and Mg₂Si_1-xGe_x samples were evaluated as a function of temperature. It indicated that Seebeck coefficients of the Si_1-xGe_x and Mg₂Si_1-xGe_x samples were higher than those of Si and Ge. Moreover, the Seebeck coefficient of Mg₂Si_0.7Ge_0.3 sample was higher than that of Mg₂Si_0.5Ge_0.5 and Si_0.5Ge_0.5 samples.     

Enhanced electrochemical activity and long-term stability of Ni–YSZ anode derived from NiO–YSZ interdispersed composite particles

Nickel oxide–yttira stabilized zirconia (NiO–YSZ) interdispersed composite (IC) particles were prepared by a mechanochemical processing using NiO and YSZ nanoparticles. Transmission electron microscopy (TEM) revealed that primally particles of YSZ (75 nm) and NiO (160 nm) were presented alternatively in the composite particles. Specific surface area (SSA) decreased from 8.6 to 7.1 m²/g during the mechanochemical processing. The SSA reduction suggested that the chemically bound NiO/YSZ hetero-interfaces were formed during the processing. Scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS) visualized that the anode made from the IC particles consisted of three-dimensional textured structure of fine Ni and YSZ networks (grain size of them was approximately 500 nm) with 34 vol% of porosity. The anode demonstrated not only low polarization of 152 mV at 1 A/cm² even under the operation at 700 °C but also long-term stability for 920 h.