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        검색결과 1,238

        351.
        2020.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We report an analysis of two poorly studied eclipsing binary stars, GSC 04396-00605 and GSC 04395-00485 (recently named V455 Dra and V454 Dra, respectively). Photometric data of the two stars were obtained using the 1-m Korean telescope of the LOAO operated by KASI while monitoring the cataclysmic variable DO Dra in the frame of the Inter-Longitude Astronomy (ILA) project. We derived periods of 0.434914 and 0.376833 days as well as initial epochs JD 2456480.04281 and JD 2456479.0523, respectively, more accurate than previously published values by factors 9 and 6. The phenomenological characteristics of the mean light curves were determined using the New Algol Variable (NAV) algorithm. The individual times of maxima/minima (ToM) were determined using the newly developed software MAVKA, which outputs accurate parameters using "asymptotic parabola" approximations. The light curves were approximated using phenomenological and physical models. In the NAV algorithm, the phenomenological parameters are well determined. We derived physical parameters using the Wilson-Devinney model. In this model, the best-fit parameters are highly correlated, thus some of them were fixed to reasonable values. For both systems, we find evidence for the presence of a cool spot and estimate its parameters. Both systems can be classified as overcontact binaries of EW type.
        4,000원
        352.
        2020.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 실험은 CAM 식물인 칼랑코에(Kalanchoe blossfeldiana) 에 이산화탄소 시비 및 다양한 일장처리를 통한 생육반응을 조사하여 탄소자원화 기술 도입 방안을 모색하고 고품질 분화 묘 생산을 하고자 수행되었다. 실험은 서울여자대학교 ICT스마트형 유리온실에서 실시하였으며, 공시 재료는 칼랑코에 Kalanchoe blossfeldiana ‘Lion’, ‘Fikalrudak’ 두 품종이다. 일장은 8시간, 12시간, 16시간으로 처리하였으며 이산화탄소는 22:00~04:00에 평균 400㎛ol・mol-1(대조구)와 800㎛ol・mol-1로 처리했다. 엽수는 칼랑코에 ‘Lion’ 품종의 경우, 8시간과 12시간 일장에서, 칼랑코에 ‘Fikalrudak’ 품종의 경우, 8시간 일장에서 이산화탄소 농도 상승에 따라 증가하였다. 초장은 품종에 관계없이 일장 8시간에서 이산화탄소 농도를 400㎛ol・mol-1에서 800㎛ol・mol-1로 증가시킬 때 감소하였다. 칼랑코에 ‘Lion’ 품종에서, 미성숙엽의 엽장과 엽폭은 이산화탄소 농도 상승에 따라 일장 8시간과 12시간에서 증가하였다. 하지만, 칼랑코에 ‘Fikalrudak’ 품종의 미성숙엽 엽장과 엽폭은 이산화탄소 농도에 영향을 받지 않아 품종에 따른 반응 차이가 있는 것으로 판단된다. 마디수는 품종과 일장에 관계없이 이산화탄소 농도를 800㎛ol・mol-1로 증가시켰더니 증가하였으며, 개화소요일 수는 이산화탄소 농도에 영향을 받지 않았다. 개화는 품종에 따라 차이가 있었으며 칼랑코에 ‘Lion’ 품종에서는 8시간과 12시간 일장에서, 칼랑코에 ‘Fikalrudak’ 품종에서는 8시간 일장에서 나타났다. 이상의 결과로 칼랑코에는 이산화탄소 농도에 관계없이 단일 조건에서만 효과적으로 개화하며, 이산화탄소 시비는 칼랑코에 잎의 생산과 마디 생산을 촉진시킬 수 있었 다. 그러나 이산화탄소 고농도 시비는 칼랑코에 개화 품질에 부정적인 영향을 줄 수 있으므로 시비 단계, 품종 등에 따른 적합한 시비 방법이 다르게 적용되어야 한다.
        4,000원
        353.
        2020.03 구독 인증기관 무료, 개인회원 유료
        Enamel knot (EK)—a signaling center—refers to a transient morphological structure comprising epithelial tissue. EK is believed to regulate tooth development in early organogenesis without its own cellular alterations, including proliferation and differentiation. EKs show a very simple but conserved structure and share functions with teeth of recently evolved vertebrates, suggesting conserved signaling in certain organs, such as functional teeth, through the course of evolution. In this study, we examined the expression patterns of key EK-specific genes including Dusp26 , Fat4, Meis2, Sln , and Zpld1 during mice embryogenesis. Expression patterns of these genes may reveal putative differentiation mechanisms underlying tooth morphogenesis.
        4,000원
        354.
        2020.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated the efficacy of four Brucella (B.) abortus recombinant proteins, namely adenylate kinase (Adk), nucleoside diphosphate kinase (Ndk), 50S ribosomal protein (L7/L12) and preprotein translocase subunit (SecB), as a combined subunit vaccine (CSV) against B. abortus infection in BALB/c mice. Immunoblotting assay showed that these four recombinant proteins as well as pcold-TF vector reacted individually with Brucella-positive serum, but not with Brucella-negative serum. The peripheral blood CD4+ T cell population was increased in CSV-immunized mice compared to PBS and pcold-TF vector groups. In addition, CSV and pcold-TF groups displayed induced IgG1 and IgG2a antibodies production compared to PBS and RB51 group, whereas IgG2a titer was higher than IgG1 titer in CSV group. The secretion profiles of IgG1 and IgG2a production together with an enhancement of CD4+ T cell population suggested that CSV did not only induce T helper 1 (Th1) T cell immunity but also humoral immunity. Therein, Th1 T cell immunity is more predominant in eliminating intracellular bacteria B. abortus. Furthermore, CSV immunization significantly reduced the bacterial burden in the spleen as well as the spleen weight in comparison to PBS and pcold-TF groups. Altogether, combination of these antigens could be potential to induce protective immunity against B. abortus infection in animals.
        4,000원
        355.
        2020.03 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        Royal jelly (RJ) is a gelatinous substance that bees produce to feed bees and queen bees. It’s frequently sold as a dietary supplement to treat a variety of physical ailments and chronic diseases. While it has long been used in traditional medicine, its applications in Western medicine remain controversial. The inhibitory effect of royal jelly on osteoarthritis was investigated in primary cultured rat cartilage cells and monosodium-iodoacetate (MIA)-induced arthritis rat model 10-hydroxy-2-decenoic acid (10-HAD) is the main fatty acid present in RJ. Among the criteria for RJ quality analysis, 10-HAD content has been proposed as a freshness parameter. We investigated the effect of RJ on the improvement of osteoarthritis on SD rats and they were divided into five groups. In this study, we examined the effect of enzymatic royal jelly (ERJ) administration on osteoarthritis. To determine the antiinflammatory effects of RJ, tumor necrosis factor alpha (TNF-α) and Interleukin-6 (IL-6) expression were measured after lipopolysaccharide (LPS) activation in RAW 264.7 cells. In in vivo animal study, osteoarthritis was induced by intra-articular injection of MIA into knee joints of rats. As a results, ERJ showed that TNF-α and IL-6 levels were decreased by ERJ treatment in a dosedependent manner. In conclusion, ERJ extract was able to inhibit articular cartilage degeneration by preventing extracellular matrix degradation and cartilage cell damage. It was considered that ERJ extract may be a potential therapeutic treatment for degenerative osteoarthritis.
        4,000원
        356.
        2020.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this research, a new medium-entropy alloy with an equiatomic composition of FeCuNi was designed using a phase diagram (CALPHAD) technique. The FeCuNi MEA was produced from pure iron, copper, and nickel powders through mechanical alloying. The alloy powders were consolidated via a high-pressure torsion process to obtain a rigid bulk specimen. Subsequently, annealing treatment at different conditions was conducted on the four turn HPT-processed specimen. The microstructural analysis indicates that an ultrafine-grained microstructure is achieved after post-HPT annealing, and microstructural evolutions at various stages of processing were consistent with the thermodynamic calculations. The results indicate that the post-HPT-annealed microstructure consists of a dual-phase structure with two FCC phases: one rich in Cu and the other rich in Fe and Ni. The kernel average misorientation value decreases with the increase in the annealing time and temperature, indicating the recovery of HPT-induced dislocations.
        4,000원
        358.
        2019.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        After the permanent shutdown of K1 in 2017, decommissioning processes have attracted great attention. According to the current decommissioning roadmap, the dismantling of the activated components of K1 may start in 2026, following the removal of its spent fuel. Since the reactor vessel (RV) and reactor vessel internal (RVI) of K1 contain massive components and are relatively highly activated, their decommissioning process should be conducted carefully in terms of radiological and industrial safety. For achieving maximum efficiency of nuclear waste management processes for K1, we present activation analysis of the segmentation process and waste classification of the RV and RVI components of K1. For RVI, the active fuel regions and some parts of the upper and lower active regions are classified as intermediate-level waste (ILW), while other components are classified as low-level waste (LLW). Due to the RVI’s complex structure and high activation, we suggest various underwater segmentation techniques which are expected to reduce radiation exposure and generate approximately nine ILW and nineteen very low level waste (VLLW)/LLW packages. For RV, the active fuel region and other components are classified as LLW, VLLW, and clearance waste (CW). In this case, we suggest in-situ remote segmentation in air, which is expected to generate approximately forty-two VLLW/LLW packages.
        4,000원
        359.
        2019.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The present study was designed to determine the effect of barn or cycle of grazing on changes of biochemical metabolites in prepartum and changes of milk composition in postpartum of dairy cows. For this purpose, a total of sixteen 25 months old Holstein primiparous dairy cows were allocated in two groups (n=8) with an average body weight of 571.61 ± 35.30 kg (Barn) and 578.10 ± 39.20 kg (Grazing). The study was conducted from June 2018 to October 2018. Results revealed that barn raised dairy cows had a higher increase in their serum albumin and calcium level on day 14 prepartum. However, the level of palmitic acid, saturated fatty acid increased significantly, and the level of fat, oleic acid, γ-linoleic acid, arachidonic acid and unsaturated fatty acids decreased significantly in barn raised dairy cow’s milk on day 14 postpartum. There were no significant differences observed with respect to all other biochemical metabolites, fatty acids and minerals between barn raised and cycle grazing dairy cows during prepartum and postpartum. Our study results could serve to a better understanding of barn raised cow with respect to changes of biochemical metabolites in prepartum and changes of milk composition, fatty acids and minerals content in grazing dairy cows in postpartum for estimating their physiological status.
        4,000원
        360.
        2019.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To attenuate and control the spread of infectious disease, a body of research has been conducted to generate safe vaccines and to continue national-level surveillance. However, understanding on viability and persistence of avian influenza virus (AIV) in infected carcasses, and effective disposal approaches are still limited up to date. Here, using HA test and RT-PCR, we assessed active status of AIV and degradation of viral RNA in collected specimens at different sites and time points. First, AIV infectivity was recovered until day 2, and viral nucleic acids persisted to day 14 and 21 in inorganic and organic samples, respectively, in sealed vials incubated at room temperature. Second, AIV was totally inactivated in all examined specimens, and viral RNA was not detectable at all time points tested at least one month post-infection in AIV-inoculated carcasses buried directly in soil or fiber reinforced plastic (FRP) bin. Lastly, among different burial sites in South Korea, 6 out of 17 sampling sites in Jeonbuk province showed the presence of viral genetic materials, while the rest of the field samples displayed neither the presence of infective AIV nor detectable viral RNA. This study showed a linear relation between time and degradation degree of viral RNA in buried samples suggesting that burial disposal method is effective for the control or at least attenuation of spread of AI infection in infected animals although consistent monitoring is required to verify safety of disposal.
        4,000원