255 research outputs found

    Preparation of sodium hexatitanate photocatalysts by a flux method for photocatalytic steam reforming of methane

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    Fine crystals of sodium hexatitanate (Na₂Ti₆O₁₃) were prepared by a flux method for photocatalytic steam reforming of methane (PSRM) to produce hydrogen. The examined parameters for the preparation in this study were the solute concentration in the molten sodium chloride salt and the cooling rate from the molten mixture. As a reference, another sample was prepared by a solid state reaction method, which corresponds to the preparation without the sodium chloride flux. The prepared samples consisted of hexagonal rod-like microcrystals of monoclinic structure with various morphology, particle size, crystallite size, aspect ratio, and specific surface area. The solute concentration affected the length and the aspect ratio of the rod-like structure although the cooling rate did not so much. The samples were loaded with 0.05 wt% of Rh cocatalyst nanoparticles, which was well dispersed oxide species on the surface. The Rh-loaded samples exhibited photocatalytic activity for hydrogen production in the PSRM. It was found that the photocatalytic production rate varied with the various structural parameters, especially correlated with the crystallite size of the rod-like Na₂Ti₆O₁₃ fine crystals

    Biosynthesis of unnatural glycolipids possessing diyne moiety in the acyl chain in the green sulfur photosynthetic bacterium Chlorobaculum tepidum grown by supplementation of 10,12-heptadecadiynic acid

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    AbstractUnnatural glycolipids possessing the diyne moiety in their acyl groups were successfully biosynthesized in the green sulfur photosynthetic bacterium Chlorobaculum (Cba.) tepidum by cultivation with supplementation of 10,12-heptadecadiynic acid. Monogalactosyldiacylglycerol (MGDG) and rhamnosylgalactosyldiacylglycerol (RGDG) esterified with one 10,12-heptadecadiynic acid were primarily formed in the cells, and small amounts of glycolipids esterified with the two unnatural fatty acids can also be detected. The relative ratio of these unnatural glycolipids occupied in the total glycolipids was estimated to be 49% based on HPLC analysis using a evaporative light scattering detector. These results indicate that the acyl groups in glycolipids, which play important roles in the formation of extramembranous antenna complexes called chlorosomes, can be modified in vivo by cultivation of green sulfur photosynthetic bacteria with exogenous synthetic fatty acids. Visible absorption and circular dichroism spectra of Cba. tepidum containing the unnatural glycolipids demonstrated the formation of chlorosomes, indicating that the unnatural glycolipids in this study did not interfere with the biogenesis of chlorosomes

    Capsaicin enhances astaxanthin action in liposomes

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    We previously demonstrated that co-encapsulation of the potent antioxidant astaxanthin (Asx) and tocotrienols into liposomes results in synergistically higher antioxidative activity than the calculated additive activity of each individual antioxidant-containing liposome, due to intermolecular interactions between terminal ring moieties of the two antioxidants and the polyene chain and the triene moiety. We reported that intermolecular interactions depend on the stereochemistry of Asx, and change the electronic state of the Asx polyene moiety. Based on these findings, we hypothesized that antioxidants that interact with Asx at the terminal ring and polyene moieties may enhance the antioxidative activity. Herein, we selected two candidate antioxidants, capsaicin (Cap) and resveratrol, based on their structures, in which the compounds exhibit similar characteristics to tocotrienols. We evaluated the antioxidative capacities of liposomes co-encapsulating Asx and the selected candidates. Based on hydroxyl radical scavenging activity, Cap was found to synergistically enhance the antioxidative activity of Asx at an optimal Asx/Cap ratio. Intermolecular interactions between Asx and Cap are necessary for the synergistic effect, and the Asx stereoisomer 3R,3’R-form (Asx-R) was predicted to most potently interact. Liposomes co-encapsulating Asx-R and Cap exhibited clear synergistic antioxidative activity at an optimal ratio, whereas liposomes co-encapsulating the other Asx stereoisomer and Cap did not demonstrate such activity. Computational chemistry analysis showed that changes in the electronic state of the polyene moiety of Asx-R are crucial for the synergistic activity. These results suggest that antioxidants that can change the electronic state of Asx via intermolecular interactions may enhance the function of Asx

    Assessing the validity of two-dimensional video analysis for measuring lower limb joint angles during fencing lunge

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    IntroductionThe fencing lunge (lunge), characterized by minimal body rotation, offers a movement well-suited for 2D video analysis. However, to the best of our knowledge, the validity of 2D video analysis for fencing has not been verified. This study aimed to validate 2D video analysis by comparing lower limb joints (hip, knee, and ankle joints) angles during lunge using both 2D video analysis and 3D motion analysis methods.MethodsTwenty-two male fencers performed lunge trials that were simultaneously recorded using eight motion capture cameras (Qualisys Miqus M1) and two digital video cameras (Sony AX-450 and AX450a).ResultsThe 2D video analysis results exhibited an extremely large correlation in knee joint angles of the front and rear legs in the sagittal with those from 3D motion analysis (r = 0.93–0.99). However, while a robust correlation was found between the ankle joint angles of the front and rear legs (r = 0.82–0.84), a large bias was also observed (−5.23° to −21.31°). Conversely, for the hip joints of the rear leg, a moderate correlation (r = 0.31) and a large bias (−10.89°) were identified.ConclusionsThe results of this study will contribute to the development of coaching using 2D video analysis in competition settings because such analysis can be a useful alternative to 3D motion analysis when measuring the knee joint angle of the front leg and rear leg in the sagittal plane. However, for the ankle joint angle, further research on the optimal shooting position and height of the digital video camera is needed, whereas for the hip joint angle, 3D motion analysis is recommended at this time

    The exposure of field-grown maize seedlings to weed volatiles affects their growth and seed quality

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    Plants exposed to volatiles emitted from artificially damaged conspecific or heterospecific plants exhibit increased resistance to herbivorous insects. Here, we examined whether volatiles from artificially damaged weeds affect maize growth and reproduction. Seven days after germination, maize seedlings were exposed to volatiles emitted by artificially damaged mugwort (Artemisia indica var. maximowiczii) or tall goldenrod (Solidago altissima) plants either separately, or as a mixture of the two, for seven days. Unexposed seedlings were used as controls. Treated and control seedlings were cultivated in an experimental field without any insecticides applied. Plants exposed to either of the three volatile treatments sustained significantly less damage than controls. Additionally, seedlings exposed to either goldenrod or mixed volatiles produced more leaves and tillers than control plants. Furthermore, a significant increase in the number of ears was observed in plants exposed to the volatile mixture. In all treated plants, ear sugar content was significantly higher than that in the controls. Further, we cultivated seedlings that were either exposed to the volatile mixture or unexposed, under the conventional farming method using pesticides. Similar significant differences were observed for sugar content, number of tillers, leaves, damaged leaves, and ears. Laboratory experiments were conducted to further evaluate the mechanisms involved in the improved performance of volatile-treated plants. A significant reduction in the growth of common armyworm (Mythimna separata) larvae was observed when maize plants were exposed to the volatile mixture. This treatment did not affect the amount of jasmonic acid in the seedlings, whereas salicylic acid content increased upon exposure. The characteristic differences in chemical composition of mugwort and goldenrod volatiles were confirmed and, in turn, the volatile mixture differed significantly from the volatiles of either species

    Required and received SNRs in coded modulation

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    Coded modulation techniques aim at reducing the required signal-to-noise ratio (SNR) over the Gaussian channel with an average energy constraint; however, such techniques tend to degrade the received SNR. We studied the balance of required and received SNRs for a realistic system design
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