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        검색결과 116

        21.
        2012.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of the present study was to investigate the effect of IFN- on prostaglandin synthesis, cyclooxygenase-2 (COX-2) gene expression in vitro and concentration of progesterone (P4) in endometrial cells. Epithelial and stromal cells cultured in vitro were isolated from bovine endometrium and stimulated with increasing doses of IFN- (0, 0.02, 0.2 and 2 ug/ml). Human chorionic gonadotropin (hCG, 1.5 IU/ml) was used as a positive control. Prostaglandin and levels in the culture media were analyzed by enzyme immunoassays and total RNA was extracted from the cells for RT-PCR. P4 concentrations of blood samples were assayed by chemiluminescent immuno assays system. In epithelial cells, COX-2 gene expression was increased in the presence of IFN- (p<0.05), but it was not significantly different in all groups of stromal cells except for 2 ug/ml IFN- group (p<0.05). Although IFN- did not affect and production in epithelial cells, it decreased and production significantly in stromal cells (p<0.05). In vivo experiment, blood concentration of P4 was significantly increased after addition of IFN- (1 ug/ml). The results indicate that PG production was mediated by COX-2 expression in stromal cells but it was not affected in epithelial cells and this suggest that treatment of IFN- could improve the implantation environment of uterine by maintenance of high P4 concentration.
        4,000원
        22.
        2011.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Procymidone is a fungicide with anti-androgenic properties widely used to protect fruits from fungal infection, which induces an excessive reactive oxygen species production in male reproductive organs. In this study, to clarify whether procymidone affect the cellular antioxidant system of prostate at onset of puberty, gene expression patterns of the representative antioxidant enzymes such as cytoplasmic glutathione peroxidase (GPx1), phospholipid hydroperoxide GPx (PHGPx), selenoprotein P (SePP), cytoplasmic copper/zinc superoxide dismutase (SOD1), and manganese SOD (SOD2) were investigated in the rat ventral prostates exposed to procymidone using real-time RT-PCR analyses. Seven-week-old Sprague-Dawley rats castrated at 6 weeks old were treated with procymidone (25, 50, or 100 mg/kg per day) orally for 7 consecutive days after testosterone propionate (0.4 mg/kg per day) administration by subcutaneous injection. As compared to normal control animals, GPx1 mRNA expression in prostates significantly increased by the administration with TP and/or procymidone. However, PHGPx and SOD1 mRNA levels significanatly decreased by over 25 mg/kg of procymidone treatment and SePP and SOD2 mRNA levels was significanatly reduced by over 50 mg/kg of procymidone treatment. These findings indicate that procymidone may affect the antioxidant system of prostatic cells in up-regulation mode of GPx1, but in down-regulation modes of PHGPx, SePP, SOD1, and SOD2, suggesting that procymidone may affect differently the cellular antioxidant system of prostate according to the exposure doses.
        4,000원
        23.
        2011.11 KCI 등재 구독 인증기관·개인회원 무료
        개인정보의 보호에 관한 종래의 논의는 행정의 공정성‧투명성‧신뢰성의 확보 및 국민권익의 보장을 목적으로 하는 행정절차의 실현과정에서 제기된 것이다. 행정절차는 국민의 행정참여를 도모하여 행정의 민주화‧적정화‧능률화를 꾀하려는 데 그 목적이 있는 바, 여기서 행정청을 포함한 공공기관과 대등한 위치에 당사자로서의 국민을 설정하기 위해공공기관이 보유한 행정정보의 활용은 필수적이라 할 수 있다. 그러나 관련기관에 행정정보를 제공하거나 이용토록 하기도 하고 행정정보를 직접 국민에게 공표하도록 하면서 오히려 그 개념상 개인정보를 포함할 수밖에 없는 행정정보의 활용에 대한 적절한 제한설정이 요구되게 된 것이다. 그리하여 적절한 행정절차에 부차적으로 기능하던 기존의 행정상 정보공개 및 정보보호 제도가 정보사회를 수렴하는 행정정보에 관한 규범으로 체계화되기에 이르렀다. 그와 같은 배경에는 전자정부의 출범요인인 정보기술의 발전은 개인정보를 통합 관리할 수 있게 함으로써 오히려 디지털화된 개인정보의 유출 가능성을 증폭시키고 있다는 점과 전자정부의 구현원리이자 운영원칙인 행정정보의 공개 및 공동이용은 대상정보의 성격상 개인정보보호와 상충될 수 있다는 점이 관여한다. 따라서 헌법상 알 권리‧행정수요‧개인정보의 보호가치가 모순되지 아니하도록 관련 법규범의 조화로운 적용과 실천적인 운용이 요청된다고 할 것이다.이와 같은 관점에서 이 글에서는 컴퓨터시스템과 네트워크를 활용한 방법으로 정보전달의 신속성‧정확성 확보, 지리적‧시간적 한계의 극복, 종이문서사용의 절감 등의 효과를 유발하는 행정정보의 공동이용 및 범죄예방이라는 공익적 목적을 수행하기 위하여 폐쇄회로텔레비전을 운용함으로써 경찰인력의 소모를 감쇄시킬 수 있는 화상정보의 수집이라는 행정정보의 활용이 지니는 역기능으로서 개인정보에 관한 정보주체의 권리제한의 적합성에 관해 살펴보기로 한다. 지난 해 5월 5일부터 시행된 「전자정부법」은 행정정보 공동이용의 범위를 확장하고 있는 반면 지난 9월 30일부터 시행된 「개인정보 보호법」은 영상정보처리기기의 운용에 관한 제한을 설정하면서도 정보주체의 권리보장을 명시하고 있기에 상호 충돌된 가치에 있으므로 그 향방이 주목될 뿐 아니라 두 쟁점 모두 개인정보를 포함하는 행정정보 활용에 관한 것이기에, 결국 헌법상 일반원칙에 부합하고 개인정보의 보호에 관한 국제기준에 부합하는지에 대하여 실질적으로 되짚어보아야 하기 때문이다. 이 글은 이와 관련하여 위 두 법률의 상호관련성에서의 바람직한 개정방향의 단초를 짚어보아 개인정보자기결정권 보장에 관한 헌법합치적 법제도를 타진해본다.
        24.
        2011.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The stress-strain responses and oxidation properties of cold-rolled Zr-1.5Nb-O and Zr-1.5Nb-O-S alloys were studied. The U.T.S. (ultimate tensile strength) of cold-rolled Zr-1.5Nb-O-S alloy with 160 ppm sulfur (765 MPa) were greater than that of Zr-1Nb-1Sn-0.1Fe alloy (750 MPa), achieving an excellent mechanical strength even after the elimination of Sn, an effective solution strengthening element. The addition of sulfur increased the strength at the expense of ductility. However, the ductile fracture behavior was observed both in Zr-Nb-O and Zr-Nb-O-S alloys. The beneficial effect of sulphur on the strengthening was observed in the cold rolled Zr-1.5Nb-O-S alloys. The activation volume of cold-rolled Zr-1.5Nb decreased with sulfur content in the temperature region of dynamic strain aging associated with oxygen atoms. Insensitivity of the activation volume to the dislocation density and the decrease of the activation volume at a higher temperature where the dynamic strain aging occurs support the suggestion linking the activation volume with the activated bulge of dislocations limited by segregation of oxygen and sulfur atoms. The addition of sulfur was also found to improve the oxidation resistance of Zr-Nb-O alloys.
        4,000원
        25.
        2011.01 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In this study, the heat flow of the plant scale aluminum extrusion process was investigated to establish optimum continuous heat treatment conditions. During the extrusion of 6061 aluminum alloy, processing parameters such as the extrusion pressure, speed and temperature histories of billets were logged as a function of time. The surface temperature of the billets increased at constant ram speed, while it decreased with decreases of the ram speed. In order to maintain the billet temperature within a solutionizing temperature range prior to the succeeding water quenching step, the ram speed or the temperature of the blower should be controlled. The temperature histories of the billets during the extrusion and hot air blowing processes were successfully simulated by using the velocity boundary model in ANSYS CFX. The methodology to design an optimum process by using a commercial simulation program is described in this study on the basis of the metallurgical validation results of the microstructural observation of the extrudates. The developed model allowed the advantages of taking into account the motion of the extrudate coupled with the temperature change based on empirical data. Calculations were made for the extrudate passing through the isothermal chamber maintained at appropriate temperature. It was confirmed that the continuous heat treatment system is beneficial to the productivity enhancement of the commercial aluminum extrusion industry.
        4,000원
        27.
        2010.11 구독 인증기관 무료, 개인회원 유료
        3,000원
        28.
        2010.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        A series of molecular dynamic (MD), finite element (FE) and ab initio simulations are carried out to establish suitable modeling schemes for the continuum-based analysis of aluminum matrix nanocomposites reinforced with carbon nanotubes (CNTs). From a comparison of the MD with FE models and inferences based on bond structures and electron distributions, we propose that the effective thickness of a CNT wall for its continuum representation should be related to the graphitic inter-planar spacing of 3.4Å. We also show that shell element representation of a CNT structure in the FE models properly simulated the carbon-carbon covalent bonding and long-range interactions in terms of the load-displacement behaviors. Estimation of the effective interfacial elastic properties by ab initio simulations showed that the in-plane interfacial bond strength is negligibly weaker than the normal counterpart due to the nature of the weak secondary bonding at the CNT-Al interface. Therefore, we suggest that a third-phase solid element representation of the CNT-Al interface in nanocomposites is not physically meaningful and that spring or bar element representation of the weak interfacial bonding would be more appropriate as in the cases of polymer matrix counterparts. The possibility of treating the interface as a simply contacted phase boundary is also discussed.
        4,000원
        29.
        2010.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The Pyeongan Supergroup can be divided into seven lithostratigraphic units (Moscovian to Early Triassic?) in the Samcheok coalfield and four lithostratigraphic units (Bashkirian to Artinskian) in the Yeongwol coalfield of South Korea. On the basis of fusulinid biostratigrapic data in the Yeongwol coalfield, the boundary between the Carboniferous and Permian strata of the Pyeongan Supergroup has been considered as unconformity since the Kasimovian and Gzhelian strata are missing. Protriticites and Triticites, which are the cosmopolitan index fusulinids indicating the Kasimovian and Gzhelian age, are not found from the uppermost part of the Geumcheon and Pangyo Formations. Recently some fusulinids such as Xenostaffella koreaensis, Hanostaffella magna, and Fusulina danyangensis found from the uppermost part of the Geumcheon and Pangyo Formations are recognized as the early Kasimovian-type fusulinids, although the upper Kasimovian- to Gzhelian-type fusulinids are still missing.
        4,200원
        30.
        2010.09 구독 인증기관 무료, 개인회원 유료
        This study deals with the design of a bi-directional liquid damper for a SDOF structure. Two dampers are usually needed to reduce wind-induced responses of tall structures since they are along and across wind ones. The proposed damper has the advantage of controlling both responses with a single damper. The damper shows dynamic behavior of both tuned liquid column damper (TLCD) and tuned sloshing damper (TSD) in the direction of two axes perpendicular with each other. This paper presents experimental verification to confirm its control performance. First, shaking table test is carried out to investigate reducing responses of a SDOF structure by the damper. Control performance of the damper is expressed by the transfer function from shaking table accelerations to SDOF structure ones. Testing results show that the damper reduced bi-directional responses of a SDOF structure. Also, it reduced torsion responses. It was confirmed from system identification results that damping ratio of a SDOF structure increased by the bi-directional liquid damper.
        4,000원
        32.
        2010.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Sperm chromatin integrity is essential for successful fertilization and development of an embryo. Reported here is a quantification of DNA fragments which is intimately associated with reproductive potential to provide one of criteria for sperm chromatin integrity. Three sperm populations were considered: CONTROL (no treatment), UV irradiation (48mW/, 1h) and (oxidative stress induced by hydrogen peroxide, 10 mM, 50 mM and 100 mM). DNA fragments in boar sperm were evaluated by using ligation-mediated quantitative real-time polymerase chain reaction (LM-qPCR) assay, which relies on real-time qPCR to provide a measure of blunt 5' phosphorylated double strand breaks in genomic DNA. The results in agarose gel electrophoresis showed no significant DNA fragmentation and no dose-dependent response to . However, the remarkable difference in shape and position was observed in melting curve of LM-qPCR. This result supported that the melting curve analysis of LM-qPCR presented here, could be more sensitive and accurate than previous DNA fragmentation assay method.
        4,000원
        33.
        2010.03 구독 인증기관 무료, 개인회원 유료
        In this study, nonlinear dynamic characteristics of a tuned liquid column damper (TLCD) varying with the amplitude of excitation input are evaluated through shaking table tests and numerical model of a TLCD. The tuned mass damper (TMD) analogy of a TLCD is used to simplify the formulation, in which involves equivalent viscous damping of the inherent nonlinear damping term of a TLCD. The equivalent TMD model of a TLCD shows that the dynamic behavior of a TLCD is affected by the natural frequency, the damping ratio and the ratio of total liquid mass to the mass in horizontal column of a TLCD. Shaking table test is performed to obtain experimental transfer functions that describe the dynamic behavior of a TLCD specimen subjected to a harmonic loading with various excitation amplitudes. Transfer functions for various excitation amplitudes are measured from shaking table acceleration to both the liquid displacement within a TLCD container and the control force produced by a TLCD specimen. Also, the dissipation energy due to the inherent damping of a TLCD is measured from the shaking table test varying with excitation amplitude. The variation of design parameters of a TLCD according to the excitation amplitude is investigated by comparing the transfer functions obtained from the shaking table test to those derived from the TMD analogy of a TLCD. These results showed that both the natural frequency and the mass ratio of a TLCD are independent on the variation of excitation amplitude, while the damping ratio of a TLCD increases with larger excitation amplitude.
        4,000원
        35.
        2009.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Using the spectroscopic data secured with the Hamilton Echelle Spectrograph at Lick Observatory, we found the physical condition of the planetary Nebula NGC 6210. The spectral line profiles of the permitted and forbidden lines have been analyzed using IRAF and StarLink/Dipso. The hydrogen number densities (NH) are 2,000-20,000 cm-3, and the electron temperatures are 8,100-10,300 K based on the forbidden lines. The expansion velocities, derived from the Full Width at Half Maximum (FWHM) and the double peak of the line profiles, are in the range of 10 to 45 kms-1. The expansion velocities imply a shell structure with an accelerated nebular gas. We also derived abundances from the permitted lines of CII, CIII, NII, NIII, OII, and OIII, which may have been formed through the fluorescence mechanism. NGC 6210 is likely to be evolved from a progenitor of more than 3M⊙, which had been born near the Galactic plane.
        4,200원
        36.
        2009.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study intended to the optimal conservation method and to make an application scheme for the fossil locality of the Quaternary Hamori Formation at the northeastern coast of Mt. Songak. Many kinds of innumerable fossils are found from the Hamori Formation in the study area: Footprints of hominid, trace fossils of invertebrates, bird, artiodactyla, proboscidea, carnivores, unclassified footprints, and body fossils (arthropoda, gastropoda, mollusca, and plants). The formation has been outcropped and eroded out with innumerous fossils by the strong wave action of storm and typhoon. Korean government recognized the dangerous situation of the important fossils and decided to conserve the formation for the national heritage. Method D1 (conservation hall or museum on the fossil locality) may be the best way to protect the fossil locality from all the natural activities and to do the research, exhibition, education, and sightseeing together. The application of the geologic materials from the fossil locality should preferentially focus on the collection and research which should be accompanied by exhibition, education, and sightseeing. The application scheme may be stepped into three stages during 10 years: (1) systematic conservation and publicity during 2005-2007, (2) establishment of wellorganized museum during 2008-2010, and (3) international museum with the optimized roles 2011-2014.
        4,000원
        37.
        2009.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In 2007, just after the recession of the Changma, anomalously long rainy period (from July 30 to August 15) occurred in Korea. To identify the cause of the sustained rainy period, we performed synoptic analysis and the associated air motions. The behavior of each air parcel trajectory associated with atmospheric motion was then investigated. As a result, three particular phenomena occurring at latitudes lower than 40˚N were discovered. First, a mass of relatively cold air, referred to as E, made a deep intrusion from 20˚N to 60˚N. Second, this intrusion was accompanied by another mass of air called dE. It was colder and drier than E and originated from the mid-troposphere over the tropical ocean. Third, dE and E rotated clockwise three times over a period of 17 days over the Northwestern Pacific and blocked the westerly waves imbedded in the zonal flow from propagating. Two additional phenomena were observed at latitudes higher than 40˚N. First, the cold core system, while approaching from the west with low geopotential values at its center, was stagnated over Shanxi China. It enhanced the northward intrusion of dE and E, and then diminished. The subsequent low system showed similar evolution as the first one. Second, a warm core anticyclone was formed over Lake Baikal, blocking the westerlies for 13 days and contributed to the persistent northward incursion of warm moist air. Moreover, a horizontally extended intrusion of upper level clouds from the tropics to 50˚N, which may be interpreted as a tropical plume, was found around the end of the period (from August 12 to 15, 2007) with successive tropical nights over Korea.
        5,700원
        38.
        2009.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was carried out to evaluate the nuclear, cytoplasmic maturation and developmental potential of bovine oocytes selected by brilliant cresyl blue (BCB) as indirect measurement of oocytes growth phase. Cumulus-oocyte complexes (COCs) were collected from 2 to 8 mm follicles from slaughterhouse Hanwoo ovaries. The COCs were divided into stained cytoplasm to blue (BCB+) and unstained (BCB-) according to their ooplasm BCB coloration stained by of BCB after 90 min. Selected COCs were cultured in a TCM 199 for 18 to 26 h. Nuclear maturation and total cell number was evaluated after in vitro maturation (IVM) or in vitro culture (IVC) using Hoechst 33342, and cytoplasmic maturation was evaluated by intracellular glutathione (GSH) assay before (0 h) and after (24 h) IVM. The oocyte diameters were not differed significantly between BCB+ () and BCB+ () groups (p>0.05). However, the proportion of metaphase II oocytes in BCB+ group was significantly higher than BCB- group after IVM (p<0.05). GSH content of BCB+ group oocytes was significantly higher than that of BCB- group just after collection ( vs. , p<0.05), but not varied after IVM( and for BCB+ and BCB- respectively; p>0.05). The proportion of blastocyst formation and total cell number in BCB+ group (23.5% and ) was significantly higher than that in BCB- (9.8% and ; p<0.05). The results indicate that BCB+ group oocytes may provide a cellular and functional basis for the greater developmental competence in Korean Native Cow (KNC) oocytes.
        4,000원
        39.
        2008.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Hydrogeologic properties of a well field around middle mountainous areas in Pyosun, Jeju volcanic island were examined based on water level monitoring, geologic logging and pumping test data. Due to the alternating basaltic layers with varying permeability in the subsurface, it is difficult to analyze the hydraulic responses to artificial pumping and/or natural precipitation. The least permeable layer, detrital materials with clay, is found at a depth of 200 m below surface, but it is not an upper confining bed for lower main aquifer. Nevertheless, this layer may serve as a natural barrier to vertical percolation and to contaminant migration. Water levels of the production wells are dominantly affected by pumping frequently, while those of the remote observation wells are controlled by ambient precipitation. Results of pumping tests revealed a possible existence of horizontal anisotropy of transmissivity. However, some results of this study include inherent limitations enforced by field conditions such as the consistent of groundwater production and the set of time periods for the cessation of the pumping prior to pumping tests.
        4,300원
        40.
        2008.09 구독 인증기관 무료, 개인회원 유료
        Real-time hybrid testing technique (RT-HYTT) is a structural dynamic testing method that the numerical calculation of the equations of motion of a structure and the experimental measurement of the reaction forces resulting from the application of this motion to the numerical structure are simultaneously implemented in real time. In this paper, structural control performance of the magneto-rheological (MR) damper installed in a real-scaled 5 story building is experimentally evaluated through real-time hybrid test method. In this method, a numerical substructure is based on a structural model identified from the forced vibration testing results of a real-story building, and an MR damper that is used as an experimental substructure is physically tested with a universal testing machine (UTM). In the test, load cell on the UTM measure the force necessary to attain the required story displacement and these structural reaction forces are returned to the computer for use in next time step calculation of a numerical structural model. Test results show that the higher level of control force generated by the Mr damper causes the lower level of controlled response of a structure.
        4,000원
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