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        검색결과 44

        3.
        2021.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The role of transient receptor potential vanilloid receptor-1 (TRPV1) has been primarily investigated in pain sensory neurons. Relatively, little research has been performed in testicular cells. TRPV1 is abundantly expressed in Leydig cells of young adult mice. This study was conducted to determine the role of the TRPV1 channel in Leydig cells. TRPV1 modulators and testosterone were treated to the mouse Leydig cell line TM3 cells for 24 h. Capsaicin, a TRPV1 activator, dose-dependently induced cell death, whereas capsazepine, a TRPV1 inhibitor, inhibited capsaicin-induced cell death. Testosterone treatment reduced capsaicin-induced cell death. High concentrations of testosterone decreased TRPV1 mRNA and protein expression levels. However, TRPV1 modulators did not affect testosterone production. These results showed that capsaicin induced cell death of Leydig cells and that testosterone reduced capsaicininduced cell death. Our findings suggest that testosterone may regulate the survival of Leydig cells in young adult mice by decreasing the expression level of TRPV1.
        4,000원
        4.
        2019.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Reproductive potential decreases with age. A decrease in male fertility is due to a combination of morphological and molecular alterations in the testes. Transient receptor potential vanilloid receptor-1 (TRPV1) is associated with aging and lifespan, and its activation causes apoptotic cell death in various cell types. However, the effect of TRPV1 on testicular apoptosis in aged mice has not yet been reported. TRPV1 knockout (KO) mice had a longer lifespan than that of wild-type (WT) mice. Lifespan was increased by 11.8% in male TRPV1 KO mice compared to that in WT mice. TRPV1 KO males lived approximately 100 days longer than WT males on average, and the maximum lifespan was markedly extended in TRPV1 KO mice compared with that in WT mice. The TRPV1 expression levels were highly increased in the testes of older mice. TRPV1 was expressed in the entire testes region of the old mice. In addition, old TRPV1 KO mice had lower testicular apoptosis than that of WT mice. Our results show that TRPV1 induces testicular apoptosis and suggest that TRPV1 may be associated with testicular aging.
        4,000원
        10.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We investigated the period variation for 79 eclipsing binary systems using 20 years (1990-2009) of EROS, Macho, and OGLE survey observations. We discovered 9 apsidal motions, 8 mass transfers, 5 period increasing and decreasing systems, 12 light-travel-time effects, 5 eccentric systems and 40 other systems showing no period variations. We select 3 representative eclipsing binary systems; EROS 1052 for apsidal motion, EROS 1056 for mass transfer, and EROS 1037 for the light-travel-time effect. We determine the period variation rate (dP/dt), orbital parameters of the 3rd body (e3, ω3, f(m3), P3, T3), apsidal motion parameters (dω/dt, U, Ps, Pa, e) and apsidal motion period by analyzing the light curves and O-C diagrams.
        3,000원
        11.
        2015.04 구독 인증기관·개인회원 무료
        Riptortus pedestris (F.) (Hemiptera: Alydidae) attacks several leguminous crops and its reproductive success is found to be affected by the leguminous host types. Ooencyrtus nezarae Ishii (Hymenoptera: Encyrtidae) is an egg parasitoid of R. pedestris and its quality attributes depend on the host egg quality. We, thus, investigated the performance of O. nezarae on eggs of R. pedestris fed on different leguminous seeds. Eggs collected from R. pedestris female adults obtained from rearing on one of the four hosts such as soybean, adzuki bean, mung bean, and cowpea seeds were exposed as a batch (n=15) to a single 4 to 5 day-old mated female O. nezarae. The eggs exposed were collected after 24 h. Number of parasitized eggs, sex ratio, development times, and adult emergence were recorded. The maximum number of eggs parasitized by O. nezarae were the eggs of mung bean fed R. pedestris. Eggs produced from the adzuki bean fed bugs had the lowest parasitization. There was no difference recorded in the developmental time of parasitoids emerged from the eggs of R. pedestris fed on different legumes. Proportion of male O. nezarae was highest on the eggs of cowpea seed fed adult bugs (26%); the lowest of that was found on the eggs of mung bean fed bugs (22.4%). Ooencyrtus nezarae can successfully parasitize eggs of R. pedestris regardless of hosts food sources. However, eggs of mung bean fed R. pedestris, among the tested legumes, were found to be of the best quality for reproductive success of O. nezarae.
        12.
        2013.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        During sintering of Ni-electrode multi-layer ceramic capacitors (MLCCs), the Ni electrode often becomes discontinuous because of its lower sintering temperature relative to that of BaTiO3. In an attempt to retard the sintering of Ni, we introduced passivation of the Ni powder. To find the optimal passivation conditions, a thermogravimetric analysis (TGA) was conducted in air. After passivation at 250oC for 11 h in air, a nickel oxide shell with a thickness of 4- 5 nm was formed on nickel nanoparticles of 180 nm size. As anticipated, densification of the compacts of the passivated Ni/NiO core-shell powder was retarded: the starting temperature of densification increased from ~400oC to ~600oC in a 97N2-3H2 (vol %) atmosphere. Grain growth was also retarded during sintering at temperatures of 750 and 1000oC. When the sintering atmosphere was changed from wet 99.93N2-0.07H2 to wet 99.98N2-0.02H2, the average grain size decreased at the same sintering temperature. The conductivity of the passivated powder sample sintered at 1150oC for 8 h in wet 99.93N2-0.07H2 was measured to be 3.9 × 104 S/cm, which is comparable with that, 4.6 × 104 S/ cm, of the Ni powder compact without passivation. These results demonstrate that passivation of Ni is a viable means of retarding sintering of a Ni electrode and hence improving its continuity in the fabrication of BaTiO3-based multi-layer ceramic capacitors.
        4,000원
        13.
        2013.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This experiment was carried out to determine the effect of different spectrum conversion greenhouse films (red, blue, red+blue) to changing microclimate and subsequent effect on growth and quality of lettuce (Lactuca sativa L.), tomato (Solanum lycopersicum L.), and melon (Cucumis melo L.) Transmission of PAR (photosynthetic active radiation, 400-700 nm) under red, blue, and blue+red (BR) films was higher by 7.2, 7.6, and 5.8%, respectively, as compared with control greenhouse film. Light transmission in the 300-1100 nm wave band was 91.6% and 91.3% under red and blue films, respectively, compared to 86.4% under control film. Mean daytime temperature in greenhouse was slightly higher in red and blue film and mean night time temperature was higher in BR film. There were no significant differences in relative humidity among the films. Number of leaves and plant fresh weight of lettuce were higher under BR film. Total number of marketable tomato fruits was greater under blue and BR film and fruit weight was heavier under red and blue film compared to control film. Under BR and red film melon fruit weight was increased by 140 g and 80 g respectively, as compared to control film. Sugar content in melon and tomato fruits was not affected by covering films.
        4,000원
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