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        검색결과 18

        1.
        2023.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This article conducts a multidimensional quantitative data analysis of writing scores and related variables such as word frequency, stroke number, and the number of components in the corpus of Chinese character acquisition of primary Chinese learners from non-Chinese culture circles, and then analyzes the cognitive characteristics and rules of Chinese character acquisition reflected in the data from the perspective of cognitive psychology. Data analysis shows that there are “stroke number effect” and “component number effect” when learners write Chinese characters, and the influence of the stroke number and component number on writing depends on the level of Chinese characters in the whole book frequency, and the dividing line is about 200. From the perspective of cognitive rule, frequency, stroke number and component number affect the whole process of perception, memory and extraction of Chinese characters. There are differences in the recognition methods of Chinese characters with different frequencies when writing. Learners use compressed and holistic recognition for high-frequency words (frequency>200), while partial and feature recognition for medium and low-frequency words (frequency≤200), and the basic units of feature recognition are strokes and components.The score of wrongly used characters is not significantly correlated with frequency, strokes and components, and the cognitive rules reflected by wrongly used characters need further study.
        5,400원
        2.
        2021.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 중국 초등학교 구성원들의 교수효과성을 높이는 데 있어서 교사가 인식하고 있는 교장의 수업지도성 현황을 알아보고 더 효율성 있는 학교조직문화를 조성하기 위해서 학교 조직문화 유형에 따라 교사가 지각한 교장의 수업지도성 및 교수효능감 차이와 각 변인 간의 상관관계 및 영향관계를 규명하 는 데 목적이 있다. 그 실증분석 결과에 의하면 교사의 배경변인(성별, 담당학년, 교직 경력)에 따라 저학년, 교직 경력 20년 이상의 남교사들은 여교사들보다 수업지도성, 학교조직문화, 교수효능감에 대한 인식이 유의미한 수준에서 높게 나타났다. 그리고 교장의 직접적인 수업지도성인 수업개선과 수업평가를 잘 할수록 학교조직문화와 교사의 교수효능감에 미치는 영향력이 더 크게 나타났다. 또한 혁신문화일수록 교수효능감의 하위변인에 미치는 영향력이 더 크게 나타났다. 따라서 교장의 수업 지도성은 학교조직문화와 교사의 교수효능감에 영향을 미치고, 학교조직문화 역시 교사의 교수효능감에 영향을 미치는 것으로 확인되었다. 아울러 교장의 수업지도성이 학교조직문화를 통해 교사의 교수효능감에 간접적으로 영향을 준다는 점도 확인되었다. 연구결과를 토대로 학교현장의 교수효과성을 극대화하기 위해서 교장의 수업지도성을 제고하고 유익한 학교조직문화를 형성함으로써 효과적인 학교를 만드는 노력을 필요로 하고 있음을 제시하였다.
        9,800원
        3.
        2020.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Fish ovarian germline stem cells (OGSCs) that have the abilities to self-renew and differentiate into functional gametes can be used in various researches and applications. A main issue to be solved for effective utilization of fish OGSCs is the development of their stable in vitro culture condition, but only few researches about fish OGSC culture have been reported so far. In this study, in order to find the clues to develop the culture condition for OGSCs from Japanese medaka (Oryzias latipes), we tried to establish somatic cell lines as a candidate for the feeder cells and evaluated its supporting effects on the culture of ovarian cell populations from O. latipes. As the results, the somatic cell lines could be established only from the embryonic tissues among three tissues derived from embryos, fins and ovaries. Three embryonic cell lines were tested as a feeder cell for the culture of ovarian cell population and all three cell lines induced cell aggregation formation of the cultured ovarian cells whereas the feeder-free condition did not. Furthermore, a significant cellular proliferation was observed in the ovarian cells cultured on two of three cell lines. As a trial to increase the capacity of the cell lines as a feeder cell that supports the proliferation of the cultured ovarian cells, we subsequently established a stable line that expresses the foreign O. latipes fibroblast growth factor 2 (FGF2) from an embryonic cell line and evaluated its effectiveness as a feeder cell. The ovarian cells cultured on FGF2 expressing feeder cells still formed cell aggregates but did not show a significant increase in cellular proliferation compared to those cultured on non-transformed feeder cells. The results from this study will provide the fundamental information for in vitro culture of medaka OGSCs.
        4,000원
        4.
        2018.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Although the efforts to establish fish embryonic stem cells (ESCs) have been made for a long time, derivation of authentic ESCs that possess pluripotency is still difficult suggesting a need for the stepwise optimization of the methods to establish fish ESCs. Primary culture of the blastomeres from the embryos at blastula stage is a critical step for establishing continuous ESC lines. Here, we evaluated the effects of temperatures and basal media on primary culture of blastula embryo-derived blastomeres in marine medaka (Oryzias dancena). The blastomeres were isolated from the blastula embryos and cultured in various conditions designed by the combination of 4 temperatures including 28°C, 31°C, 34°C, and 37°C and 2 basal media including Dulbecco’s modified eagle’s medium (DMEM) and Leibovitz’s L-15 medium (L15). With the exception of a case cultured in L15 at 31°C, the rate of primary cell adherence reached 100% when the blastomeres were cultured over 31°C. The period for primary adherence was significantly shorter in the groups cultured in 34°C and 37°C than in the ones in 28°C and 31°C. The proportion of subculture was significantly high in the group cultured in DMEM at 31°C compared to the other groups. Collectively, we demonstrated that the culture in DMEM at 31°C was effective to primary culture of the blastomeres derived from blastula embryos.
        4,000원
        5.
        2016.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        There is a growing interest in the application of primary hepatocytes for treatment of liver diseases in humans and for drug development. Several studies have focused on long-term survival and di-differentiation blocking of primary hepatocytes in an in vitro culture system. Therefore, the present study also aimed to optimize an in vitro culture system using primary rat hepatocytes. Primary rat hepatocytes from 6-week-old male Crl:CD rats were isolated using a modified two-step collagenase perfusion. Healthy 3.5 × 106 primary rat hepatocytes were seeded into a 2 dimensional (2D) culture in a 25T culture flask coated with collagen type I or into a 3D culture in a 125-ml spinner flask for 7 days. Production of plasma protein (ALB and TF), apoptosis (BAX and BCL2), and CYP (CYP3A1) related genes were compared between the 2D and 3D culture systems. The 3D culture system had an advantage over the 2D system because of the relatively high expression of ALB and low expression of BAX in the 3D system. However, the level of CYP3A1 did not improve in the 3D culture with and without the presence of a dexamethasone inducer. Therefore, 3D culture has an advantage for albumin production and primary rat hepatocyte survivability, but a low expression of CYP3A1 indicated that primary rat hepatocytes require a high–density culture for stress reduction by continuous flow.
        4,000원
        6.
        2013.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Spermatogonial stem cells (SSCs) developed into sperms through spermatogenesis have been utilized as a useful tool in the field of regenerative medicine and infertility. However, a small number of highly qualified SSCs are resided in the seminiferous tubule of testis, resulted in developing effective in-vitro culture system of SSCs for solving simultaneously quantitative and qualitative problems. Presently, SSCs can be enriched on testicular stromal cells (TSCs), but there are no systematic researches about TSC culture. Therefore, we tried to optimize culture condition of TSCs derived from mouse with different strains. For these, proliferation and viability were measured and compared by culturing ICR outbred or DBA/2 inbred mouse-derived TSCs at 35 or 37℃. In case of ICR strain, primary TSCs cultured at 37℃ showed significantly higher proliferation and viability than those at 35℃ and significant increase of proliferation and viability in sub-passaged TSCs was detected in the 35℃ culture condition. Moreover, sub-passage of primary TSCs at 35℃ induced no significant effects on proliferation and viability. In contrast, in case of DBA/2 strain, significantly improved proliferation were detected in the primary TSCs cultured at 35℃, which showed no significant difference in the viability, compared to those at 37℃. Furthermore, sub-passaged TSCs cultured at 37℃ showed no significant differences in proliferation and viability, compared to those at 35℃. However, with significant decrease of proliferation induced by sub-passage of primary TSCs at 35℃, no significant effects on proliferation and viability were resulted from sub-passage of primary TSCs at 37℃. From these results, culture temperature of primary TSCs derived from outbred and inbred strain of mouse could be separately optimized in primary culture and subculture.
        4,000원
        7.
        2009.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Numerous bone cell culture models have been presented by the development of isolation and culturing techniques of cells. The culture of osteoblast-like cells of human origin with a specific osteoblastic phenotype has become an important experimental model in bone biology. Recently, it has become increasingly popular to utilize bone marrow cultures because these cultures are therefore thought to represent earlier stages of the osteoblast differentiation pathway. There is no report about culturing normal human osteoblast from oral and maxillofacial area. Primary cultured cells from oral and maxillofacial cancellous bone were analyzed by morphologic features, total DNA contents, ALP, osteocalcin and von Kossa staining positivity. The purpose of this study were to culture the cell population from oral and maxillofacial cancellous bone and to analyze the phenotypic expression of cultured normal human osteoblast by the bone marrow isolation technique. Growth curve of NHost showed about 45hrs of doubling time and about 70μ g/well of total DNA content. NHost showed spindle shaped cytoplasm with ovoid nucleus under preconfluency and after cellular differentiation, they formed irregular numerous nodules from stratified cellular layers under D medium. ALP activity was about 2 folds higher under control medium with 10nM 1,25(OH)2D3 than that under control medium. Osteocalcin expression was about seven folds higher under control medium with 100nM 1,25(OH)2D3 than that under control medium. Scattered mineralized nodules stained by von Kossa method were seen on the cellular layer under D medium. It suggested that NHost might be established from oral and maxillofacial area by characteristic cellular shape, ALP activity, osteocalcin expression and numerous mineralized nodules.
        4,000원
        8.
        2009.09 구독 인증기관 무료, 개인회원 유료
        Pluripotent embryonic stem (ES) cells isolated from inner cell mass (ICM) of blastocyst-stage embryos are capable of differentiating into various cell lineages and demonstrate germ-line transmission in experimentally produced chimeras. These cells have a great potential as tools for transgenic animal production, screening of newly-developed drugs, and cell therapy. Miniature pigs, selectively bred pigs for small size, offer several advantages over large breed pigs in biomedical research including human disease model and xenotransplantation. In the present study, factors affecting primary culture of somatic cell nuclear transfer blastocysts from miniature pigs for isolation of ES cells were investigated. Formation of primary colonies occurred only on STO cells in human ES medium. In contrast, no ICM outgrowth was observed on mouse embryonic fibroblasts (MEF) in porcine ES medium. Plating intact blastocysts and isolated ICM resulted in comparable attachment on feeder layer and primary colony formation. After subculture of ES-like colonies, two putative ES cell lines were isolated. Colonies of putative ES cells morphologically resembled murine ES cells. These cells were maintained in culture up to three passages, but lost by spontaneous differentiation. The present study demonstrates factors involved in the early stage of nuclear transfer ES cell isolation in miniature pigs. However, long-term maintenance and characterization of nuclear transfer ES cells in miniature pigs are remained to be done in further studies.
        4,000원
        9.
        2007.09 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 hG-CSF의 발현을 유도적으로 조절하기 위한 FIV-Tet-On lentivirus vector system을 구축하고자 하였다. hG-CSF는 호중성구 계열 세포의 증식과 분화, 생존에 영향을 미치는 물질로서, 이 유전자의 발현을 증가시키기 위하여 FIV-Tet-On vector 상의 hG-CSF나 rtTA2SM2 서열의 3' 위치에 WPRE 서열을 도입하였다. 구축된 각각의 vector는 293FT 세포에 일시적으로 transfection하여 virus를 생산하였으며, 이 virus를 일차 배양 세포인 CEF와 PFF에 감염시켰다. 각 세포에 전이된 hG-CSF의 발현 양상을 관찰하기 위하여 doxycycline을 첨가하거나 첨가하지 않은 배지에서 배양한 후 quantitative real-time PCR, Western blot과 ELISA를 이용하여 hG-CSF 유전자의 발현 정도를 비교 측정한 결과, CEF에서는 WPRE가 hG-CSF의 3' 위치에 도입된 경우에 발현량과 유도율이 가장 높은 것으로 나타났고, PFF에서는 rtTA 서열의 3'위치에 도입된 경우에 발현량과 유도율이 가장 큰 것으로 확인되었다. 이 FIV-Tet-On vector system은 형질 전환 동물의 생산이나 유전자 치료에서 문제시되는 외래 유전자의 지속적인 과다 발현에 의한 개체의 생리적인 부작용을 최소화하기 위한 해결 방법으로 제시될 수 있을 것이다.
        4,000원
        11.
        2005.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        It is very little known that the molecular mechanisms control growth, cell differentiation, and invasion of ameloblastoma into bone. Tissue culture methods have also been used extensively for studies of the cell biology of ameloblastoma. The purpose of this study were to examined the ultrastructural features of ameloblastoma, and to apply these results to examine the pathogenesis of ameloblastoma in the future. Amelobalstoma was primarily cultured under 0.1, 0.15 and 1.2mM Ca++ of KBM bullet kit at 370C and 5% C02. For transmission electronmicroscopy(TEM), cultured ameloblastoma cells were immediately fixed in 2.0% glutaraldehyde in O.lM cacodylate buffer(pH 7.4) at 40C for 1h The ultrathin sections were stained with uranyl acetate and lead citrate, and examined by TEM. The obtained results were as follows. Primay culture ameloblastoma grown in 0.1 mM Ca++ showed interlacing papillary projections without desmosome within early passage(3-4). Primary culture amelobalstoma under high calcium showed prominent desmosomes or tight junctions within early passage. There was evidence of cellular degeneration, as exemplified by nuclear pyknosis, the margination and clumping of the chromatin, and vaculolation under high calcium. The sparse ribosomes, the cytoplasmic space filled with vacuoles, and the condensed mitochondria were seen under high calcium. From the aboving results, under high calcium primary culture ameloblastoma showed rapid cellular degeneration within early passage, indicating that the cells were gradually losing metabolíc actívitíes, leading to enventual cell death. It was thought that it would be necessary to establish cultured immortalized amelobalstoma cell line for studying the pathogenesis of odontogenic tumors.
        4,000원
        14.
        2020.06 KCI 등재 서비스 종료(열람 제한)
        Water temperature is one of the most important factors of fish survival, affecting the habitat, migration route, development, and reproduction. This experiment studied the induction level of heat shock protein (HSP70) mRNA and protein in a walleye pollock (Gadus chalcogrammus) primary hepatocyte culture based on different temperatures. Hepatocytes were attached at 7.5 °C for 24 hours. Hsp70 induction levels were then measured for 48 hours at 5, 8, 11, 14, and 17 °C. The induction level was lowest at 5 °C and generally increased with temperature until 14 °C. The induction level was reduced at 17 °C, indicating that 14 °C is the highest tolerable temperature for hepatocytes. These data indicate that primary hepatocyte cell culture is under no stress at 5 and 8 °C. Temperatures greater than 11 °C induce stress, showing similar induction patterns in both mRNA and protein in hepatocytes. The results suggest that 14 °C is the maximum internal defense temperature of walleye pollock survival.
        15.
        2018.07 KCI 등재 서비스 종료(열람 제한)
        본 연구의 목적은 초등학교 교사의 학교조직몰입에 영향을 미치는 직무수행 준비도, 학습민첩 성, 직무자율성, 학교조직문화 변인들 간의 구조적인 관계를 분석하는 것이다. 본 연구에서는 서울 시내 초등학교에 근무하고 있는 교사를 연구대상으로 하여 총 601교 중 102교, 650명에게 설문조사를 실시하여 최종 626명의 자료를 분석에 이용하였다. 수집된 자료분석을 위해서는 구조방정식을 이용하였다. 연구결과는 다음과 같다. 첫째, 직무수행 준비도, 학습민첩성, 직무자율성은 학교조직문화에 정적 직접효과를 미쳤다. 둘째, 직무수행 준비도, 직무자율성, 학교조직문화는 학교조직 몰입에 정적 직접효과를 나타냈다. 셋째, 직무수행 준비도, 직무자율성은 학교조직문화를 경유하여 학교조직몰입에 정적 간접효과를 나타냈다. 본 연구에서는 교사의 직무수행 준비도, 학습민첩성, 직무자율성이 학교조직문화에 영향을 미치는 중요 변인이었고, 또한 직무수행 준비도, 직무자 율성, 학교조직문화는 교사의 학교조직몰입에 직·간접적으로 영향을 미치는 중요 변인임을 확인하였다. 따라서 변화하는 학교조직 환경 속에서 초등학교 교사가 학교조직에 몰입할 수 있도록 하기 위해서는 교사의 직무수행 준비도, 학습민첩성, 직무자율성을 향상시킬 수 있도록 연수과정 제공, 컨설팅 지원, 교사 공동체 학습 문화 형성, 교사 리더십 향상 등을 지속적으로 지원할 필요가 있다. 아울러 교사는 학교조직문화에 영향만 받는 수동적 위치에 있는 것이 아니라 스스로 학교조직문화를 만들어가는 능동적 위치에 있다는 것을 확인하였다.
        16.
        2007.09 KCI 등재 서비스 종료(열람 제한)
        본 연구는 자궁근종 성장에 관한 분자생물학적인 기전의 이해를 위해 자궁근종 및 정상 자궁근세포의 초기 배양방법을 확립하기 위해 실시하였다. 이를 위해 최종적으로 두 가지 세포 배양 방법이 확립되었다. 그리고 안정적으로 연구(특히, 여성호르몬에 대한 반응 연구)에 사용할 수 있는 가장 적합한 세포 배양 방법이 모색되었다. 두 가지 세포 배양 조건 중 두 번째 방법(method 2)이 안정적으로 세포의 반응을 연구하는데 더 나은 방법으로 결론 내려졌고, 여
        17.
        2005.10 KCI 등재 서비스 종료(열람 제한)
        본 연구의 목적은 양파추출물의 간보호 및 항산화 효과를 조사하기 위함이다. 간 손상을 유발시키는 t-BHP (1.5 mM) 존재하에 간세포를 0, 0.01, 0.05, 0.1 및 0.3 mg/ml의 다양한 농도의 양파추출물로 1시간 동안 일차배양하였다. t-BHP는 GOT와 LDH 활성 및 TBARS 농도를 증가시켰으며 MTT값은 감소시켰다. 0.05 mg/ml 농도의 양파추출물 첨가는 t-BHP에 의해 증가된 GOT 및 LDH 활성을 감소시켰으며 0.1 mg/ml 농도의 양파추출물은 t-BHP에 의해 감소된 MTT 값을 증가시켰다. 또한 0.01 mg/ml 농도의 양파추출물 첨가는 t-BHP에 의해 증가된 TBARS 농도를 감소시켜 양파추출물이 t-BHP에 의해 유발된 간손상과 지질과산화를 억제시켰다. t-BHP 처리는 간세포의 catalase, GSH-Px 및 GSH-Rd 활성을 현저히 감소시켰다. 그러나 0.1 mg/ml 농도의 양파추출물 첨가는 t-BHP에 의해 감소된 catalase GSH-Px 및 GSH-Rd 활성을 증가시켰으며 특히 catalase 활성은 t-BHP 무첨가군 수준까지 증가시켰다. 또한 hydroxyl radical을 생성하는 Fenton 시약의 존재하에 plasmid DNA를 양파추출물과 함께 배양한 결과 양파추출물은 농도 의존적으로 hydroxyl radical에 의해 유도된 single-strand 절단을 억제하였다. 이상과 같이 간세포 일차배양에서 양파추출물은 t-BHP에 의해 유발된 간독성, 간세포 생존율 감소, 지질과산화를 농도 의존적으로 억제시켰고 또한 t-BHP에 의해 억제된 GSH-Px, GSH-Rd 및 catalase의 활성을 증가시켰다. 이와 같이 양파추출물의 간보호 및 항산화 효과는 항산화 효소 특히 catalase의 활성 증가와 hydroxyl radical에 의해 유도된 산화억제 및 이에 따른 지질과산화 억제에 기인하는 것으로 사료된다.
        18.
        2004.04 KCI 등재 서비스 종료(열람 제한)
        The objectives of present study were to investigate the effects of benzo[a]pyrene(BaP) on cytotoxicity, lipid peroxidation and antioxidant enzymes in rat hepatocyte primary culture. Primary cultures of rat hepatocytes were incubated for 24 hr, 48 hr or 72 hr in the presence of various concentrations (0, 10, 20, 30, 50 or 100 μM) of BaP. Cytotoxicity and cell viability were determined by measuring glutamic oxaloacetic transaminase(GOT) activity, lactate dehydrogenase(LDH) activity and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide(MTT) value. Lipid peroxidation was evaluated using thiobarbituric acid reactive substances(TBARS) assay. Effects on antioxidant system were determined by measuring glutathione peroxidase(GPx) activity, glutathione reductase(GR) activity and glutathione concentration. Activities of GOT and LDH, MTT value as well as TBARS concentration were not affected by up to 100 μM of BaP for 24 hr incubation. However, BaP at the concentration of 50 μM for 48 hr incubation or at the concentration of 30 μM for 72 hr incubation began to increase LDH activity and TBARS concentration but decrease MTT value, representing that BaP caused cytotoxicity and decreased cell viability in dose- and time-dependent manners. GPx activity began to be decreased by BaP at the concentration of 50 μM for 72 hr incubation. Whereas, GR activity began to be decreased by BaP at the concentration of 20 μM for 72 hr incubation. Glutathione concentration began to be decreased by BaP at the concentration of 20 μM for 72 hr incubation and was further reduced to 90% by 100 μM of BaP. These results demonstrate that BaP caused cytoctoxicity and decreased cell viability by increasing lipid peroxidation and decreasing glutathione concentration as well as activities of GPx and GR.