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        검색결과 17

        1.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Canine induced pluripotent stem cells (iPSCs) are an attractive source for veterinary regenerative medicine, disease modeling, and drug development. Here we used vitamin C (Vc) to improve the reprogramming efficiency of canine iPSCs, and its functions in the reprogramming process were elucidated. Methods: Retroviral transduction of Oct4, Sox2, Klf4, c-Myc (OSKM), and GFP was employed to induce reprogramming in canine fetal fibroblasts. Following transduction, the culture medium was subsequently replaced with ESC medium containing Vc to determine the effect on reprogramming activity. Results: The number of AP-positive iPSC colonies dramatically increased in culture conditions supplemented with Vc. Vc enhanced the efficacy of retrovirus transduction, which appears to be correlated with enhanced cell proliferation capacity. To confirm the characteristics of the Vc-treated iPSCs, the cells were cultured to passage 5, and pluripotency markers including Oct4, Sox2, Nanog, and Tra-1-60 were observed by immunocytochemistry. The expression of endogenous pluripotent genes (Oct4, Nanog, Rex1, and telomerase) were also verified by PCR. The complete silencing of exogenously transduced human OSKM factors was observed exclusively in canine iPSCs treated with Vc. Canine iPSCs treated with Vc are capable of forming embryoid bodies in vitro and have spontaneously differentiated into three germ layers. Conclusions: Our findings emphasize a straightforward method for enhancing the efficiency of canine iPSC generation and provide insight into the Vc effect on the reprogramming process.
        4,000원
        2.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        자생식물은 관상용, 약용, 식량자원으로 활용될 수 있는 잠재력을 지닌 고유 유전자원이다. 돌부추(Allium koreanum H.J. Choi & B.U. Oh)는 우리나라 해안 암반지대에 분포하는 자생식물 중 하나로, 기후변화와 서식지 감 소로 인해 보전 가치가 높은 식물이다. 이번 연구는 온도와 과산화수소가 돌부추의 발아에 미치는 영향을 조사하기 위해 수행되었다. 종자를 무처리(대조군) 또는 1% 과산화수소(H2O2)로 90분간 처리한 종자를 준비해 15, 20, 25°C 로 설정된 식물 생장 챔버에 배치하였다. 그 결과, 파종 23일 후 15°C에서 42%인 발아율이 20°C와 25°C에서 각각 18%와 0%인 발아율보다 2배 이상 높았으며, H2O2 처리 여부와 관계없이 15°C에서 발아율이 42%로 가장 높았다. H2O2 처리와 관계없이 최종 발아율 50%(T50)에 도달하는 일수는 20°C에서 가장 짧았지만, 일평균 발아율(MDG)은 15°C에서 가장 높았다. 따라서 1%의 H2O2 처리는 돌부추의 발아율에 큰 영향을 미치지 않았으며, 15°C의 온도가 돌부추의 발아율을 높이는 데 최적인 것으로 판단된다. 본 연구 결과는 돌부추의 발아를 위한 기초 연구 자료로 활 용될 수 있을 것으로 기대된다.
        4,000원
        3.
        2023.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A 9-year-old, intact female, Pungsan dog was referred for purulent vaginal discharge and depression. Abdominal radiographs revealed gas-filled and soft tissue opacity tubular structures in the mid to caudal abdomen. On ultrasonography, fluid-filled uterus and cervix accompanied by hyperechoic foci and reverberation artifacts were identified. Multiple hyperechoic foci were found within the uterine wall, indicating gas content. Escherichia coli was isolated from aerobic and anaerobic bacterial cultures. Radiological differential diagnosis of tubular shaped, dilated gas-filled structure, and gas in the wall of the structure should consider emphysematous pyometra with endometrial pneumatosis in intact female dogs with vulvar discharge.
        3,000원
        5.
        2014.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this paper, the wakes behind a square cylinder were simulated using two kinds of different turbulence models for the eddy viscosity concept such as the zero- and the one-equation model in which the former is the mixing length model and the latter is the k-equation model. For comparison between numerical and analytical solutions, we employed three skill assessments: the correlation coefficient(r) for the similarity of the wake shape, the error of maximum velocity difference(EMVD) for the accuracy of wake velocity and the ratio of drag coefficient(RDC) for the pressure distribution around the structure. On the basis of the numerical results, the feasibility of each model for wake simulation was discussed and a suitable value for the empirical constant was suggested in these turbulence models. The zero-equation model, known as the simplest turbulence model, overestimated the EMVD and its absolute mean error(AME) for r, EMVD and RDC was ranging from 20.3 % to 56.3 % for all test. But the AME by the one-equation model was ranging from 3.4 % to 19.9 %. The predicted values of the one-equation model substantially agreed with the analytical solutions at the empirical mixing length scale L=0.6b1/2 with the AME of 3.4 %. Therefore it was concluded that the one-equation model was suitable for the wake simulation behind a square cylinder when the empirical constant for eddy viscosity would be properly chosen.
        4,200원
        6.
        2011.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        꼬마배나무이 (Cacopsylla pyricola)에 저항성 품종육성을 위한 육종재료를 선발코자 월동형 성충수, 단과지내의 산란수, 과총엽내의약충수 및 수관 전체적인 그을음 발생정도를 15개 종 및 종간잡종133개 유전자원을 대상으로 조사하였다. 월동형 성충수는 Pyrus.calleryana 4.6마리, 단과지내 산란수는 P. calleryana 0.3개, 과총엽내약충수는 P. calleryana 0마리, 그리고 그을음 발생정도는 P.betulaefolia, P. calleryana, P. communis, P. hybrid (P.pyrifolia × P.communis), P. lindleyi 0으로 발생 및 피해정도가 가장 낮았으며 종간의 차이가 뚜렷하였다. 전체적으로 대목으로 이용하고 있는 콩배인P. calleryana와 P. betulaefolia가 조사 대상 유전자원 중 가장 높은 항객성(antixenosis)을 보였으나 품질개량에 많은 기간이 요구됨에 따라 실용적으로는 서양배(P. communis) 중 ‘Conference', 'Cascade','Bosc', 'Winter Nelis' 가 가장 낮은 발생 및 피해정도를 보여 꼬마배나무이 저항성 품종 육성을 위한 좋은 육종재료로 판단되었다.
        4,000원
        7.
        2009.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        고준위폐기물 처분장의 기본적인 기능은 단기간에 과도한 방사성핵종이 유출되는 것을 방지하는데 있다. 이를 위해서는, 처분시스템의 구성요소들과 관련된 많은 기술 기준이 개발되고 수립되어야 한다. 처분장 안전성평가는 합리적으로 단순화된 모델에 바탕을 두고 처분장의 미래 전개에 대한 정량적인 결과를 산출하므로 안전성평가는 기술기준의 하나로 간주되고 있다. 본문에서는 평가기간, 선량 제한치 및 평가의 불확실성 등을 중심으로 안전성평가와 관련된 주요국의 기술기준을 조사하였다. 특히, 미국의 기준을 조사하는 과정에서 안전성평가에서 도출된 peak dose가 선량 제한치를 충족하지 못하는 경우, 평가기간 및 peak dose에 대한 미국 규제당국의 접근방안은 참고할만한 가치가 있음을 알 수 있었다.
        4,000원
        10.
        1994.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        도로 안전 구조물을 썰계하고 동적 퍼포먼스톨 측정하기 위하여 시행되는 충돌시험시 충돌차량의 운동량, 륙히 각가속도를 Euler 방정식의 수치적분을 통하여 구하는 기법을 셜명하였다. 수치척으로 가장 안정적인 9-array 시스댐안에 내재된 여러 형태의 7, 8-array 서브시스댐들의 시스댐 미분 방정식 빛 이들 방정식의 수치 적분시 안정성올 실험데이터를 이용하여 파악하였다. 기본척인 9-array 안에 있는 6개의 8-array 시스댐들은 모두 수치적으로 안정성올 보였고 12개의 7-array 시 스댐들중 6개는 안정성올 보이고 6개는 불안정하였다. 안정성올 보이는 내재된 서브시스댐을 활용하면 기본 9-array 시스댐을 구성하는 센서의 일부 고장시 효과적으로 각가속도를 측정 할 수 있는 fail-safe 시 스댐을 구 성할수있디.
        4,200원
        11.
        2015.08 KCI 등재 서비스 종료(열람 제한)
        This study was performed to investigate the effects of enhanced light transmission on plant growth, photosynthetic ability, and disease tolerance to leaf blight, anthracnose in ginseng (Panax ginseng C. A. Meyer, Araliacease family) during the early growth stage (April to June). The photosynthetic ratio, stomatal conductance, and stem diameter of plants grown under a shade net with 15% light transmission rate showed an increasing trend compared to the control plants (5% light transmission rate) although the growth of the aerial parts were not influenced significantly. Plant height, stem length, and leaf length of treated plants were not significantly different from those of the control plants. Root parameters, such as root length, diameter, and weight of treated plants increased significantly compared to the control. Yield performance (187.4 ㎏• 10 a−1) of treated plants was 55.5% higher than that of the control (150.4 ㎏• 10 a−1). Additionally, disease severity scores of treated plants were lower than those of the control plants, revealing higher survival rates. To retain high yield potential and enhance the level of disease tolerance in ginseng, we suggest the increase of light transmission rate during the early growth stage.
        12.
        2012.12 KCI 등재 서비스 종료(열람 제한)
        We investigated the changes in plasma sex steroid hormones, testosterone (T), estradiol- (), 17,-dihydroxy-4-pregnen-3-one (), 11-ketotestosterone (11KT) and cortisol levels from ribbed gunnel, Dictyosoma burgeri in associated with annual reproductive cycle. The gonadosomatic index (GSI) of females increased from November, peaked in February and decreased rapidly from March. The GSI of males also increased from November, peaked in January and then decreased gradually. In females, levels increased and remained high from December to February. The levels of T showed a similar tendency and correlated (=0.898, p<0.01) with levels. The levels of increased rapidly in February () and peaked in July (). Cortisol level was peaked in March and correlated with levels (=0.696, p<0.01). In males, the levels of T was peaked in January and then decreased rapidly. The levels of 11KT were remained high from October to January. On the other hand, the levels of fluctuated during reproductive cycle. These results suggest that plasma sex steroids in ribbed gunnels have annual periodicity, and that cortisol may involve in maturation of females.
        13.
        2012.07 서비스 종료(열람 제한)
        In higher plants, formate dehydrogenase (FDH; EC 1.2.1.2) is a NAD-dependent enzyme that catalyzes the oxidation of formate into carbon dioxide. Although FDHs have been reported to be induced by various abiotic stresses, the function of FDHs in biotic stress is rarely known. In this work, we describe the identification of pepper mitochondrial FORMATE DEHYDROGENASE1 (CaFDH1) as a positive regulator of cell death and disease resistance. Transient expression of CaFDH1 in Nicotiana benthamiana leaves caused hypersensitive response (HR)-like cell death, where D-isomer specific 2-hydroxyacid dehydrogenase signature was crucial for the induction of the cell death. Localization analysis using green fluorescence protein showed that CaFDH1 targeted to the mitochondria with the mitochondria targeting sequence at N-terminal region. However, the mitochondrial localization of CaFDH1 is not essential for the induction of HR-like cell death, because the cytosolic CaFDH1 could elicit cell death response. Silencing of CaFDH1 in pepper significantly compromised the cell death response and salicylic acid (SA) levels, but enhanced growth of Xanthomonas campestris pv. vesicatoria. In contrast, transgenic Arabidopsis overexpressing FDH1 exhibited enhanced resistance to Pseudomonas syringae pv. tomato. Taken together, these data suggest that CaFDH1 has a role in HR cell death and defense response to microbial pathogens.