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        검색결과 10

        1.
        2018.11 구독 인증기관·개인회원 무료
        Anion exchange membrane (AEM) with fixed charged cationic groups can selectively transport anionic molecules such as hydroxide anions. The AEM materials have been widely used in the wide range of applications such as polymer electrolyte fuel cells, water electrolysis, and reverse electrodialysis and electrodialysis. Commercially available AEM materials show high electrochemical resistance owing to their chemical architectural features leading to less separated hydrocarbon morphologies. Very low solubility to casting solvents and weak chemical durability to alkaline atmosphere of the AEM materials also makes it difficult to make thin and tough AEM membranes. In this study, AEM materials composed of perfluorinated architectures with improved chemical durability and intrinsically well separated morphologies were developed and evaluated.
        2.
        2017.09 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        This study conducted a social network analysis to investigate stem cell research which was actively being studied as an alternative for the treatment of intractable diseases due to infinite proliferation and differentiation ability. Papers was extracted from the PubMed database (DB) on the subject of ‘Induced Pluripotent Stem Cells (iPS) and Embryonic Stem Cells (ES)’, and ‘Adult Stem Cell (AS) and Mesenchymal Stem Cell (MS)’. Medical Subject Headings (MeSH) term was filtrated from each area. MeSH term of iPS and ES field was 148 (international), 71 (domestic), otherwise AS and MS were 89 (international), 78 (domestic). Keyword networks were visualized using degree centrality value and the core keywords compared. There was no difference in iPS and ES field compared with the domestic and international high-ranked keywords. Gene Therapy in the international level, Liver Regeneration and the Umbilical Cord in domestic were highly centered. In AS and MS fields, Neuron was high degree centrality both. Time lagged high ranked 30 keywords in slope were different, ‘Adipose Tissue’ increased both, otherwise ‘Stem Cell Transplantation’ did domestically. Although the absolute amounts of the research papers are different, research subjects had become similar to international trends following certain time lags. On the other hand research is conducted on the specific subjects in Korea. Keyword analysis will be useful method for searching a subject to actively being studied in stem cell research area.
        4,000원
        3.
        2016.10 구독 인증기관·개인회원 무료
        Endocrine system of hormones is the critical factor for the development of testes. The levels of hormones are orchestrated by a positive or negative feedback system controlled by the hyphothalamic-pituitary-gonad axis. The aim of this study was to investigate the effect of unbalanced endocrine system induced by the hemi-castration on testicular development in stallions. Four Thoroughbred stallions (age ranging from 3 to 5 yr) were used in this study. To disturb endocrine system, hemicastration has been performed on the stallions. Several parameters including testicular weight, volume, germ cell population on the cross-sections of round tubule, and the area of seminiferous tubules of stallion testes collected at the 1st hemi-castration and the 2nd hemi-castration (about 1 year after 1st hemi-castration) were compared. Testosterone levels were compared for 3 weeks before, after 1st castration, and before 2nd castration using enzyme-linked immunosorbent assay (ELISA) analysis. Immunohistochemistry (IHC) procedure was conducted to compare germ cell populations between after 1st and 2nd castration using VASA antibody. The VASA positive cell population per a cross section of round seminiferous tubule was obtained by monitoring 100 tubules. Interestingly, the weight of testes obtained at 2nd hemi-castration (384±14 g) were significantly higher compared to that of testes collected at the 1st hemi-castration (288±34 g). The volume of testes (306±34 ml) collected at the 2nd hemi-castration was higher than that of testes (169±18 ml) collected at the 1st castration. In contrast, VASA positive germ cell population on the cross section of round tubule (124.9±12.4 vs 142.9±21.6) and the area of round tubule (124±9.7 vs 122.9±1.7 mm2) were not different after 1st castration and 2nd castration. the testosterone levels in the blood collected before, after 1st castration, and before 2nd castration were not significantly different. In conclusion, the hemi-castration induces testicular development to maintain the normal reproductive systems in stallions.
        4.
        2014.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        국내 상수원을 대상으로 시행하고 있는 조류경보제는 남조류 발생 현황을 취 정수장 등 물관리 기관에 전파하여 대응조치를 유도하는 제도로 신속하고 정확한 남조류 계수를 필요로 한다. 따라서 조류경보제 발령 기준 대상 남조류인 Anabaena, Aphanizomenon, Microcystis, Oscillatoria 속의 군체 크기와 세포수의 상관관계를 조사하고 회귀식을 도출하여 군체 크기로 세포수를 계산할 수 있는 방법을 알아보고자 하였다. 2013년 8월부터 10월까지 남조류가 과다증식한 시기에 한강(팔당호), 낙동강(달성보, 창녕함안보) 및 금강(고복저수지)의 대표지점에서 남조류 시료를 채집하였으며, 조류경보제 발령 기준 대상 남조류 속의 종별 군체 크기와 세포수의 상관 관계를 조사하여 종 및 속별 회귀식을 산정하였다. 남조류의 속별 상관분석 결과는 사상형인 Anabaena와 Aphanizomenon의 r2값이 0.93 이상으로 높은 상관성을 보였으며 구형의 Microcystis는 0.76의 상관계수 값을 나타냈다. 종 별 상관분석 결과 사상형 남조류 Anabaena crassa, Aphanizomenon flos-aquae, A. issatschenkoi, Oscillatoria curviceps, O. mougeotii는 r2값이 0.89~0.96의 범위로 높은 상관성을 나타냈으며, 구형인 Microcystis aeruginosa, M. wessenbergii, M. viridis는 0.76~0.88의 상관계수 값을 나타냈다. 다른 속에 비해 상대적으로 Microcystis의 상관성이 낮게 나타난 이유는 동일한 종, 동일한 크기의 군체라도 Microcystis strain에 따라 점액질 내의 세포 밀집 정도와 세포 크기에 차이가 있기 때문이다. 본 연구 결과 도출한 회귀식을 이용하여 군체 크기 측정값을 세포수로 환산하는 방법이 기존의 세포 계수법과 비교할 때 신속하고 간편할 것으로 보인다. 향후 남조류 종별 더 정확한 회귀식을 도출하기 위해서는 많은 시료수 확보와 더불어 다른 종들에 대한 조사 연구가 진행되어야 할 것이다.
        4,000원
        5.
        2012.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Oral squamous cell carcinoma (OSCC) develops through multistep process, that is, from normal mucosa to hyperplastic area and progressed to dysplasia, carcinoma in situ, and finally to invasive carcinoma. The purpose of this study is to investigate the histological types of the transitional area from normal oral mucosa to invasive carcinoma for the baseline data to search intermediate end point markers for early detection of OSCC. For this purpose, we reviewed the 85 patients who were diagnosed as OSCC in the Department of Oral Pathology, Yonsei University College of Dentistry, from 2002 to 2008. We classified these histopathologic findings by light-microscopy, according to the histologic pattern of transitional areas. As results, stepwise transformation from normal oral mucosa, to dysplasia and to OSCC was shown in 47 patients. Intermittent lesions were seen in 16 patients, in which normal oral mucosa, dysplasia, and OSCC were alternately arranged. Twenty two patients showed abruptly transformed to OSCC from normal oral mucosa. These preliminary data will be used for searching biomarkers for early detection of OSCC.
        4,000원
        6.
        2010.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Langerhans cell histiocytosis (LCH) is a rare clinicopathologic disorder characterized by proliferation of histiocyte- like cells (langerhans cell histiocytes) accompanied by varying other inflammatory cells. LCH commonly involves the oral and maxillofacial region, but is very rarely seen. Then LCH has made it difficult to investigate the clinical and histological aspects. We investigated LCH of oral and maxillofacial region and analyzed clinical and histological characteristics. We reviewed the records of all patients who were diagnosed as LCH, retrospectively. Data included patient’s age, sex, chief complaint, clinical diagnoses, radiologic and histologic reports, and clinical course. We analyzed clinical and histological characteristics. From 2000 to 2007, 8 patients were diagnosed as LCH. 7 were children and 1 was adult. All cases involved mandible. Clinical type of all cases were“eosinophilic granuloma”. 6 cases were classified as“unifocal disease”and 2 cases were“multifocal single system diseases”. Microscopic findings commonly showed numerous histiocytes with eosinophilic cytoplasm (langerhans histiocytes). In 6 cases, immunohistochemical study was accomplished and confirmed the diagnosis of LCH. 6 cases were cured and not recurred, and 2 cases had loss of follow- up. Unifocal disease type of LCH may arise in Korean people more frequently than in western people (75% Vs 49%). Therefore, the higher frequency of unifocal disease of LCH is expected to raise the cure rate and to improve patient prognosis in Korean patients with LCH.
        4,000원
        9.
        2008.02 KCI 등재 서비스 종료(열람 제한)
        한약재 및 식용으로 사용되는 순비기나무, 번행초, 갯방풍의 재배 한계지역과 생리활성 성분의 효능은 다음과 같다. 1. 순비기나무, 갯방풍의 서해안 북방한계지역은 태안반도이며, 동해안 북방한계지역은 강원도 지역으로 확인되었고, 번행초의 서해안 북방한계지역은 전라남도이고 동해안 북방한계지역은 경상북도 울릉군 지역이었다. 2. 자생지가 해안 200 m 이내 모래점토와 점토흙이 혼합된 지역에서 직사광선은 받는 우점식생이 없는 것을 볼 때 재배 지역은 해안지역과 인접한 지역은 재배 가능지역으로 판단된다. 3. 생리활성효능을 RAW 264.7 세포와 HL-60 세포를 이용하여 확인한 결과 유효한 항염효능은 확인하지 못하였고, 항암활성을 검정한 결과 순비기나무, 번행초는 억제활성이 없었고, 갯방풍은 100μg/ml에서 60%, 200μg/ml에서 72%의 증식억제 효과를 확인하였다.
        10.
        1988.12 KCI 등재 서비스 종료(열람 제한)
        두께가 서로 다른 C3 식물의 잎은 단위엽면적당 광합성 능력에 있어서도 차이가 나는 바 잎의 내부구조와 기체교환 사이의 관계를 바탕으로 그 원인을 구명하였다. 광합성의 2대 제한요인으로 기체확산과 생화학적 과정의 상대적인 중요도를 결정하기 위해 중엽세포의 표면은 기체확산 저항의, 그리고 세포의 체적은 탄소고정 능력의 지표로 가정하였다. 즉 세포의 표면적이 증가하면 이산화탄소의 액상확산 저항이 감소하며 체적이 증대되면 carboxylation, oxygenation, 그리고 dark respiration 반응속도가 증가한다고 간주하였다. 이러한 개념을 함축하는 광합성 모형을 작성하고 이 가설의 검증을 위해 대두 품종 Amsoy잎을 이용한 실험을 수행하였다. 생장조절실내에서 200, 400, 600u mol photons m2 s1 PAR을 공급하여 서로 다른 두께의 잎을 준비하였으며 제3 및 4본엽에 대해 1,000 u mol photons m2 s1 PAR 및 28 기온 환경하에서 이산화탄소 흡수속도를 측정한 결과 세포의 체적과 표면적의 영향을 동시에 고려한 광합성 모형이 세포 표면적만을 고려한 경우 보다 실측치에 가까운 예측치를 산출하였다. 이로 미루어 세포의 표면적과 체적은 잎의 두께 및 그에 따른 광합성 능력의 예측에 적절한 변수로 간주된다.