Geranial: the alarm pheromone in the nymphal stage of the oribatid mite,Nothrus palustris

The presence of an alarm pheromone was demonstrated in the deutonymphal stage of the oribatid mite, Nothrus palustris (C. L. Koch). The active principle was identified as 3,7-dimethyl-(E)-2,6-octadienal, geranial, and was shown to be active at doses of 10–100 ng. This is the first such pheromone identified in oribatid mites.     

Cloud-point curves of the polystyrene-cyclohexane system near the critical point

Cloud-point curves for solutions of five polystyrene samples, including three well-fractionated polystyrenes, in cyclohexane have been examined near their critical points. Even for a solution of polystyrene characterized by $\text{M}{}_{\mathrm{w}}\text{M}{}_{\mathrm{n}}\text{<1.03}$, the critical point determined by the phase-volume method is generally situated on the right hand branch of the cloud-point curve. The precipitation threshold concentration is appreciably lower than the critical concentration, while the threshold temperature slightly deviates from the critical temperature. The agreement of the precipitation threshold point with the critical point has been found for a solution of polystyrene characterized by M_w=20×10⁴ and $\text{M}{}_{\mathrm{w}}\text{M}{}_{\mathrm{n}}\text{<1.02}$ in cyclohexane. The η(φ) function derived from critical miscibility data is expressed by $\text{χ(φ) = 0.2798+}\text{67.50}\text{T}\text{+0.3070φ+0.2589φ}{}^2$, which yields θ of 33.2°C and ψ₁ of 0.22.     

(Z,Z)-5,27-Tritriacontadiene: Major sex pheromone ofDrosophila pallidosa (Diptera; Drosophilidae)

A crude cuticular extract from both sexes of 3660 fruit flies (Drosophila pallidosa) was subjected to SiO₂ and AgNO₃/SiO₂ column chromatography, accompanied by bioassay for the sex pheromone activity. After three chromatographic steps, the active fraction was obtained. The main component of the active fraction was determined to be (Z,Z)-5,27-tritriacontadiene [(Z,Z)-5,27-C_33:2, on the basis of gas-liquid chromatographic analysis, chemical derivatization and gas chromatography-mass spectrometry. Synthetic (Z,Z)-5,27-C_33:2 at 5 female equivalents (FE) elicited a clear courtship response with a high courtship index amongD. pallidosa males. Therefore it was concluded that (Z,Z)-5,27-C_33:2 was a major sex pheromone component in this species.     

Immobilization of glucose oxidase and electron-mediating groups on the film of 3-methylthiophene/thiophene-3-acetic acid copolymer and its application to reagentless sensing of glucose

Enzyme electrodes were prepared by covalent immobilization of glucose oxidase (GOx) on the films of conducting copolymer obtained by electrochemical copolymerization of 3-methylthiophene and thiophene-3-acetic acid. Onto the enzyme electrodes, 2,5-dihydroxyphenyl (DHP) groups were introduced as redox mediators by the reaction of 2,5-dihydroxybenzaldehyde using alkylenediamines as linker molecules. The mediator-carrying enzyme electrodes were applied to reagentless glucose sensing system. It was found that response current to glucose was increased by introducing DHP groups, and the longer the alkylene chain of used alkylenediamine was, the higher the response current became. For a comparison, poly-l-lysine was linked onto the films of the conducting copolymer in advance, and immobilization of GOx and then introduction of DHP groups were carried out. The mediator-carrying electrode prepared thus gave higher amperometric response than those prepared with alkylenediamines, suggesting that amino groups of poly-l-lysine functioned effectively as the sites for binding GOx and DHP groups.     

Behavioral Response of Males to Major Sex Pheromone Component, (Z,Z)-5,25-Hentriacontadiene, of Drosophila ananassae Females

To identify sex pheromone components in Drosophila ananassae, the cuticular hydrocarbons were analyzed and bioassayed. After silicic acid and two silver nitrate–silicic acid chromatographic steps, active fractions containing (Z,Z)-5,25- and (Z,Z)-4,26-hentriacontadiene as the most abundant components were obtained. Both hydrocarbons could elicit male courtship behavior. The former was the more predominant compound and elicited a higher courtship index value than the latter. Cuticular hydrocarbon differences between D. ananassae and its close relative, D. pallidosa, and their roles in species recognition are discussed.     

Computational study of flow in a curved pipe with circular cross section

Laminar imcompressible flows in a circular sectioned pipe were investigated by seeking numerical solutions to the Navier-Stokes equations. Three semi-circular pipes of radius ratios 0.05, 0.143 and 0.148 were studied. These calculations covered the Dean number ranging from 183 to 3847. In the range of low and medium Dean numbers, a steady-state solution was obtained; when the Dean number was high, a three-dimensional separation and the associated secondary flow were clearly observed far downstream near the outlet. Extensive flow visualizations were made to depict the computed results.     

Spatial distributions of atmospheric concentrations of radionuclides on 15 March 2011 discharged by the Fukushima Dai-Ichi Nuclear Power Plant Accident estimated from NaI(Tl) pulse height distributions measured in Ibaraki Prefecture

ABSTRACT

A hybrid method for estimation of atmospheric concentrations of multiple radionuclides was developed and applied to NaI(Tl) pulse height records measured in Ibaraki Prefecture in the morning of 15 March 2011 when three radioactive plumes from the Fukushima Dai-Ichi Nuclear Power Plant Accident passed. The method is based on the simple principle for separation from deposited radionuclides’ contribution and the concentration estimation for multiple radionuclides. Difficulty in the concentration estimation due to complexity of surrounding terrains and geometry was overcome to obtain spatiotemporal variations in atmospheric concentrations of Xe-133, Te-132, I-131, I-132 and I-133 in the three plumes at 21 monitoring stations. The plume axis with higher I-131 concentration of 5.40 kBq m-3 than the previous estimations during the second plume was found in the northwestern inland area. A substantially lower Xe-133/I-131 concentration ratio of the first plume than those of the others was again recognized. The details of non-uniform spatial distribution of the radionuclide composition were found for each of the three plumes.     

Improving antioxidant activity and nutritional components of Philippine salt-fermented shrimp paste through prolonged fermentation

The antioxidant activity and nutritional components of Philippine salt-fermented shrimp paste were improved through prolonged fermentation (90, 180, and 360 days). The antioxidant ability against 1,1-diphenyl-2-picryhydrazyl (DPPH) radical, hydrogen peroxide, and lipid peroxidation increased significantly with prolonged fermentation and were suggested to be related with the Maillard reaction products formed, as measured by the characteristic browning and fluorescent developments. Polyunsaturated fatty acids like eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in the shrimp paste were not substantially damaged for 360 days, while free amino acid content dramatically increased at 90 days. However, excessive fermentation showed slight but significant decrease in free amino acids and increase in ammonia. These results suggest that properly prolonged fermentation would improve antioxidant ability and some nutritional value in the salt-fermented shrimp paste.     

Elasticity of nanocrystalline kyanite at high pressure and temperature from ultrasonic and synchrotron X-ray techniques

Material properties, such as elasticity data at wide-ranging conditions of pressure and temperature, attract increasing attention for material and earth sciences. In particular, polycrystalline ceramics for next-generation photonic applications are nowadays fabricated by advanced syntheses techniques operating under elevated pressures and temperatures. Herein, the elastic properties of a synthetic transparent and reinforced aluminosilicate nanoceramic composed of triclinic kyanite with minor amounts of trigonal α-alumina crystals are investigated using in situ synchrotron X-ray diffraction and ultrasonic techniques at high-pressure (up to 11 GPa) and high-temperature (300-1500 K) conditions. This not only enables the determination of the equation of state (EoS) parameters by applying the pressure-volume-temperature (P-V-T) data to the high-temperature Birch-Murnaghan EoS but also yields the elastic moduli together with their P and T derivatives from the fit of the compressional and shear wave velocities to a finite strain EoS: K_S0,300 = 186(2) GPa, K′_S0,300 = 7.2(6), (∂K_S0,300/∂T)_P = −0.023(2) GPa K⁻¹, G_0,300 = 125(1) GPa G′_0,300 = 2.3(2), (∂G_0,300/∂T)_P = −0.017(1) GPa K⁻¹. On the basis of our acquired results, we propose to predict the elastic moduli of aluminosilicate ceramics by a linear function of the ratio of AlO₆ octahedra and SiO₄ tetrahedra within the constituting phases.     

Hydrogen evolution reaction on spheroidal graphite cast iron with different pearlite areas in sulphuric acid solutions

The rate equation of hydrogen evolution reaction of spheroidal graphite cast iron with different pearlite area has been studied in sulphuric acid solutions at 298 K. The cathodic Tafel slope of ?0·130 V/decade and the reaction order with respect to the activity of hydrogen ion of 1 are obtained by linear potential sweep technique. The rate equation of hydrogen evolution reaction does not depend on the area of pearlite. There is no difference in hydrogen evolution reaction mechanisms between pure iron and spheroidal graphite cast iron.