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        검색결과 621

        221.
        2017.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Arabidopsis nucleoside diphosphate kinase 2 (AtNDPK2) is an upstream signaling molecule that has been shown to induce stress tolerance in plants. In this study, the AtNDPK2 gene, under the control of a stress-inducible SWPA2 promoter, was introduced into the genome of tall fescue (Festuca arundinacea Schreb.) plants. The induction of the transgene expression mediated by methyl viologen (MV) and NaCl treatments were confirmed by RT-PCR and northern blot analysis, respectively. Under salt stress treatment, the transgenic tall fescue plants (SN) exhibited lower level of H2O2 and lipid peroxidation accumulations than the non-transgenic (NT) plants. The transgenic tall fescue plants also showed higher level of NDPK enzyme activity compared to NT plants. The SN plants were survived at 300 mM NaCl treatment, whereas the NT plants were severely affected. These results indicate that stress-inducible overexpression of AtNDPK2 might efficiently confer the salt stress tolerance in tall fescue plants.
        4,000원
        222.
        2017.09 KCI 등재 구독 인증기관·개인회원 무료
        The present study analyzes the role of Lactic Acid Bacteria Mixture (LBM) on improving rye silage quality. Rye of four different stages (Booting, Heading, Flowering, and Late flowering) was collected and silage was prepared. The nutrient profile analysis of experimental silage groups showed no significant changes between control and LBM inoculation. Interestingly, the pH of rye silage in LBM treatments showed significant reduction than control (p<0.05) in all stages of rye silage. However, lowest pH (3.69) resulted on booting stage among other stages of rye. Subsequently significant lactic acid production was noted in all stages of LBM inoculation than control. Conversely maximum lactic acid production of (5.33%DM) was noted at booting stage followed by (4.86%DM) in heading stage. Further the lactic acid bacterial (LAB) count in LBM inoculated group showed significant increase than control. Similarly, the silage of booting stage group registered maximum LAB population (63.7 ×106CFU/g) after that heading stage (32.3 ×106CFU/g). Further significant reduction in yeast growth and no fungal growth was noted in all LPM treatment groups. Hence, LBM inoculants could be a better additive for improving rye silage quality.
        223.
        2017.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        규산 시비가 토마토 플러그 묘소질에 미치는 영향과 묘의 저온저장시 규산의 저온장해 경감효과를 검토하였다. ‘Rapito’품종을 공시하여 30일간 32구 규격의 플러그 트레이에서 육묘한 뒤, 여섯 개의 규산 처리 농도구 (8, 16, 32, 64, 128 및 256mM)를 설계하여 20일 동안 주 2회 관주 처리한 뒤, 묘소질을 대조구와 비교하였다. 처리 농도는 16mM과 32mM 처리가 초장, 엽면적, 생체중, T/R율 및 근권부 발육 등 대부분의 생육 지표에서 타 처리구에 비해 양호했으며, 특히 16mM의 농도에서 가장 좋은 묘소질을 보였으나, 64mM 이상의 고농도에서는 대조구에 비해 전반적으로 생육이 억제되는 경향을 보였다. 토마토 묘의 생리적 반응에서 엽온에서는 처리구별 차이가 나타나지 않았으나, 증산율은 32mM이상의 농도 처리구에서 기공확산 저항이 증가하면서 증산율이 감소되는 경향을 보였다. 또한, 처리 횟수에 따른 효과를 검토하기 위해 16mM농도의 규산을 20 일 동안 6, 10, 20회 관주처리 한 결과, 대부분의 생육지표에서 처리 횟수간에는 큰 차이가 없었으나, 무처리구에 비해 묘소질이 향상되었으며, 특히 뿌리표면적, 근장, root tip수등 근권부의 생육이 현저히 증가하였다. 아울러 규산처리가 저온저장시 토마토 묘의 저온장해를 감소시키는 효과가 있음을 확인하였다.
        4,000원
        224.
        2017.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Employing Halliday’s (1994) Systemic Functional Grammar approach, the present study examines the Korean EFL college students’ way of organizing thematic structures in written English texts, with special focus on the influence of learner proficiency. A total of 150 learners’ argumentative essays consisting of 50 essays each from three levels of learner groups were compared with 50 essays from its native counterparts, with inquiry focused on the thematic selection, usage of various theme features, and semantic distribution of topical themes. The results show that textual themes, multiple themes, and first person pronouns as topical themes are highly overused in the learner texts compared to the native essays. Overall, the level of proficiency significantly affects learners’ choices regarding thematic structures although the enhanced proficiency does not involve the improvement in all aspects of thematic organization. From these findings, it is suggested that the EFL writing pedagogy should pay greater attention to the effective use of thematic organization as a means of enhancing textual coherence and embrace level-specific instructions.
        6,400원
        227.
        2017.07 구독 인증기관·개인회원 무료
        This study addresses how agency costs influence the sustainability of different types of corporate governance. The luxury fashion brand could spend large sums of money on maintenance of magnificent brand image, thereby increasing the agency cost. On the contrary, the brand may hold down wasteful spending to report a gaudily financial achievement. Agency costs are defined either to vertical costs arising from the relationship between stockholders and managers, or to horizontal costs associated with the potential conflicts between majority and minority stockholders. Agency costs are measured by the value of the principal component. The study conducted regression analysis of each agency cost index, luxury fashion brand dummy and a set of control variables. The findings show that the agency costs of the firms with luxury fashion brand exceed those of control group.
        228.
        2017.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study evaluated the antimicrobial efficacy of different concentrations of ozonated water with organic matter, fetal bovine serum, at different concentrations and incubation times with bacteria. In the absence of organic matter, total eradication of up to 5 log of Escherichia (E.) coli was achieved, however, interference by organic matter led to inefficiency of ozonated water as a disinfecting agent. In addition, diminishing antimicrobial effects at higher temperatures, even in the absence of organic matter, were also demonstrated. These findings indicate that ozonated water will be a safe and effective disinfectant agent that could be useful in meat processing, especially an intestine processing, in Korean slaughter houses.
        3,000원
        229.
        2017.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The objective of this study was to determine the efficacy of ozone in sanitizing water experimentally inoculated with the gram-positive food-poisoning bacterium Staphylococcus aureus. The bactericidal effect was measured after experimentally inoculated solutions were exposed to 0, 0.5, and 1.0 ppm ozone at several time points and different temperatures, in the presence of varying concentrations of different organic matter, namely, fetal bovine serum (FBS) or cattle liver. Results revealed inhibition of the bactericidal effect in the presence of the lowest percentage of FBS, but a lower extent of the inhibition occurred when liver was used as the organic matter. It was also apparent that a higher temperature and shorter ozone exposure time had led to a more reduced bactericidal efficacy than that under a lower temperature and longer ozone exposure. This study provides insight into the potential use of ozonated water as an effective and safe disinfectant in an abattoir setting.
        3,000원
        230.
        2017.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Treatment of dextran sodium sulfate(DSS) on HeLa cells results to an enhanced susceptibility to Brucella(B.) abortus infection. An increase in the adherence, invasion and intracellular replication of B. abortus was observed in DSS-treated cells. Furthermore, a marked elevation in the intensity of F-actin fluorescence was also observed in DSS-treated cells compared with untreated B. abortus-infected cells. An upregulation of phagocytic signaling proteins by Western blot analysis demonstrated an apparent activation of ERK, p38α and JNK phosphorylation levels in B. abortus-infected DSS-treated cells compared with the control. Colocalization with LAMP-1 proteins was attenuated in DSS-treated cells upon intracellular trafficking of the pathogen compared with control cells. The results of this study demonstrated consistency with other pathogens. The uptake and intracellular replication of B. abortus is hypothesized to be stimulated by various dextran receptors such as C-type lectins that are involved in phagocytosis which can either be direct phagocytic receptors, modulators of the expression of other receptors or as opsonins leading to an enhanced internalization of B. abortus. The complexity of these interactions thus would warrant further investigation into the role of DSS in the pathogenesis of brucellosis. In summary, we conclude that DSS enhanced adhesion, phagocytosis and intracellular replication of B. abortus in epithelial cells which could lead to suppression of the innate immune system in chronic Brucella infection.
        4,500원
        231.
        2017.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We study the angular correlation function of bright (Ks ≤ 19.5) Extremely Red Objects (EROs) selected in the Subaru GTO 2 deg2 field. By applying the color selection criteria of R − Ks > 5.0, 5.5, and 6.0, we identify 9055, 4270, and 1777 EROs, respectively. The number density is consistent with similar studies on the optical − NIR color selected red galaxies. The angular correlation functions are derived for EROs with different limiting magnitude and different R −Ks color cut. When we assume that the angular correlation function w() follows a form of a power-law (i.e., w() = A−), the value of the amplitude A was larger for brighter EROs compared to the fainter EROs. The result suggests that the brighter, thus more massive high-redshift galaxies, are clustered more strongly compared to the less massive galaxies. Assuming that EROs have redshift distribution centered at hzi ∼ 1.1 with z = 0.15, the spatial correlation length r0 of the EROs estimated from the observed angular correlation function ranges ∼ 6-10 h−1Mpc. A comparison with the clustering of dark matter halos in numerical simulation suggests that the EROs are located in most massive dark matter halos and could be progenitors of L∗ elliptical galaxies.
        4,000원
        232.
        2017.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, magnetite (Fe3O4) nanoparticles were electrochemically synthesized in an aqueous electrolyte at a given potential of -1.3 V for 180 s. Scanning electron microscopy revealed that dendrite-like Fe3O4 nanoparticles with a mean size of < 80 nm were electrodeposited on a glassy carbon electrode (GCE). The Fe3O4/GCE was utilized for sensing chloramphenicol (CAP) by cyclic voltammetry and square wave voltammetry. A reduction peak of CAP at the Fe3O4/GCE was observed at 0.62 V, whereas the uncoated GCE exhibited a very small response compared to that of the Fe3O4/GCE. The electrocatalytic ability of Fe3O4 was mainly attributed to the formation of Fe(VI) during the anodic scan, and its reduction to Fe(III) on the cathodic scan facilitated the sensing of CAP. The effects of pH and scan rate were measured to determine the optimum conditions at which the Fe3O4/GCE exhibited the highest sensitivity with a lower detection limit. The reduction current for CAP was proportional to its concentration under optimized conditions in a range of 0.09-47 μM with a correlation coefficient of 0.9919 and a limit of detection of 0.09 μM (S/N=3). Moreover, the fabricated sensor exhibited anti-interference ability towards 4-nitrophenol, thiamphenicol, and 4-nitrobenzamide. The developed electrochemical sensor is a cost effective, reliable, and straightforward approach for the electrochemical determination of CAP in real time applications.
        4,000원
        239.
        2017.04 구독 인증기관·개인회원 무료
        Chinese longhorned beetle (CLB; Anoplophora chinensis) and Asian longhorned beetle (ALB; A. glabripennis) were accidentally introduced into the US from the Asia back in 90s’ and have been causing economic damage on hardwood species in the US. An international cooperative team made field surveys in Korea to find parasitoids of CLB and ALB using sentinel logs that were infested with eggs of the two cerambycids.. As a result, two parasitic wasps of Anopolophora species were newly recognised from Korea: Aprostocetus anoplophorae Delvare (Eulophidae) as an egg parasitoid of CLB and Leluthia honshuensis Belokobylskij & Maeto (Braconidae) as a larval parasitoid of ALB. Identification was made using both morphological and molecular data. Morphological information was provided along with images of developmental stages and adults.
        240.
        2017.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We report our research on aluminum mirror optics for future infrared astronomical satellites. For space infrared missions, cooling the whole instrument is crucial to suppress the infrared background and detector noise. In this aspect, aluminum is appropriate for cryogenic optics, because the same material can be used for the whole structure of the instrument including optical components thanks to its excellent machinability, which helps to mitigate optical misalignment at low temperatures. We have fabricated alu- minum mirrors with ultra-precision machining and measured the wave front errors (WFEs) of the mirrors with a Fizeau interferometer. Based on the power spectral densities of the WFEs, we con rmed that the surface accuracy of all the mirrors satis ed the requirements for the SPICA Coronagraph Instrument. We then integrated the mirrors into an optical system, and examined the image quality of the system with an optical laser. As a result, the total WFE is estimated to be 33 nm (rms) from the Strehl ratio. This is consistent with the WFEs estimated from the measurement of the individual mirrors.
        3,000원