7,175 research outputs found

    The comparison of the aid allocation of Korea in the 1950s and the 1960s to that of contemporary Uganda

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    노트 : Prepared for Korea and World Economy Conference X

    Quasi-Eigenstate Evolution in Open Chaotic Billiards

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    We experimentally studied evolution of quasi-eigenmodes as classical dynamics undergoing a transition from being regular to chaotic in open quantum billiards. In a deformation-variable microcavity we traced all high-Q cavity modes in a wide range of frequency as the cavity deformation increased. By employing an internal parameter we were able to obtain a mode-dynamics diagram at a given deformation, showing avoided crossings between different mode groups, and could directly observe the coupling strengths induced by ray chaos among encountering modes. We also show that the observed mode-dynamics diagrams reflect the underlying classical ray dynamics in the phase space.Comment: 4 pages, 4 figure

    Sound waves delay tomato fruit ripening by negatively regulating ethylene biosynthesis and signaling genes

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    AbstractRegulation of tomato fruit ripening may help extend fruit shelf life and prevent losses due to spoilage. Here, tomato fruit were investigated whether sound treatment could delay their ripening. Harvested fruit were treated with low-frequency sound waves (1kHz) for 6h, and then monitored various characteristics of the fruit over 14-days at 23±1°C. Seven days after the treatment, 85% of the treated fruit were green, versus fewer than 50% of the non-treated fruit. Most of the tomato fruit had transitioned to the red ripening stage by 14 days after treatment. Ethylene production and respiration rate were lower in the sound-treated than non-treated tomatoes. Furthermore, changes in surface color and flesh firmness were delayed in the treated fruit. To investigate how sound wave treatment effects on fruit ripening, the expression of ethylene-related genes was analyzed by quantitative real-time RT-PCR analysis. The expression level of several ethylene biosynthetic (ACS2, ACS4, ACO1, E4 and E8) and ripening-regulated (RIN, TAGL1, HB-1, NOR, CNR) genes was influenced by sound wave treatment. These results indicated that sound wave treatment delays tomato fruit ripening by altering the expression of important genes in the ethylene biosynthesis and ethylene signaling pathways

    Synergistic Antibacterial Effect between Silibinin and Antibiotics in Oral Bacteria

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    Silibinin is a composition of the silymarin group as a hepatoprotective agent, and it exhibits various biological activities, including antibacterial activity. In this study, the antibacterial activities of silibinin were investigated in combination with two antimicrobial agents against oral bacteria. Silibinin was determined with MIC and MBC values ranging from 0.1 to 3.2 and 0.2 to 6.4 μg/mL, ampicillin from 0.125 to 64 and 0.5 to 64 μg/mL, gentamicin from 2 to 256 and 4 to 512 μg/mL, respectively. The ranges of MIC50 and MIC90 were 0.025–0.8 μg/mL and 0.1–3.2 μg/mL, respectively. The antibacterial activities of silibinin against oral bacteria were assessed using the checkerboard and time-kill methods to evaluate the synergistic effects of treatment with ampicillin or gentamicin. The results were evaluated showing that the combination effects of silibinin with antibiotics were synergistic (FIC index <0.5) against all tested oral bacteria. Furthermore, a time-kill study showed that the growth of the tested bacteria was completely attenuated after 2–6 h of treatment with the MBC of silibinin, regardless of whether it was administered alone or with ampicillin or gentamicin. These results suggest that silibinin combined with other antibiotics may be microbiologically beneficial and not antagonistic

    Stability of wheat germ oil obtained by supercritical carbon dioxide associated with lipase ethanolysis

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    Wheat germ oil was extracted using an environmental friendly solvent, supercritical carbon dioxide (SCCO2) at a semi-batch flow extraction process. The supercritical carbon dioxide (SC-CO2) extraction was carried out to extract oil at temperature of 40°C and pressure of 25 MPa. Ethanolysis was performed with 1,3-regiospecific lipase at different temperatures (40 to 70°C) to produce diglycerides and monoglycerides containing fatty acid ethyl esters. For determination of stability, wheat germ oil obtained by ethanolysis reactants was characterized by measuring the acid value, peroxide value, free fatty acid contents, thiocyanate method, DPPH radical scavenging effect and rancimat test. The optimized condition of 40°C shows the highest oil stability among the various conditions.Keywords: Supercritical carbon dioxide, wheat germ oil, ethanolysis, immobilized lipases, oil stabilityAfrican Journal of Biotechnology Vol. 12(22), pp. 3570-357
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