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        검색결과 8

        1.
        2018.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        유해 미생물에 오염된 농업용수는 배추의 재배기간 동안 지속적인 식중독세균 오염의 주원인이 될 수 있다. 농업용수는 야생동물 및 가축의 분변에 의해 오염되고 있다. 따라서 본 연구는 야생동물의 출입이 농업용수의 미생물학적 안전성에 미치는 영향을 조사하기 위하여 수행하였다. 이를 위하여 산악지대에 위치한 배추 재배농가에 사용되는 농업용수의 상류에서부터 하류까지 시기별 위생지표세균 오염도와 수원 상류의 야생동물의 출입 빈도를 조사하였다. 배추를 재배하는 기간 동안 멧돼지, 고라니 등 총 37회의 야생동물들이 농업용수 수원 근처에서 관찰되었다. 농업용수의 위생지표세균을 조사한 결과, 3종의 위생지표세균 모두 사람의 출입이 없는 상류에서부터 검출 되었으며 대장균군, 대장균, 장구균의 오염도는 각각 2.13~4.32 log MPN/100mL, 0.26~2.03 log MPN/100mL, 1.43~3.49 log MPN/100mL 수준이었다. 대장균군과 대장균의 오염수준은 배추 이식기 보다 수온이 낮은 수확기에 낮았으나 장구균은 시기별로 큰 차이가 없었다. 본 연구의 결과로 미루어 볼 때 농업용수의 오염은 야생동물의 출입과 관련이 있을 것으로 판단된다.
        4,000원
        3.
        2012.03 구독 인증기관 무료, 개인회원 유료
        This study was conducted in order to evaluate the alleviating effects of Phellodendrin cortex water extract (PCWE) on skin aging in hairless mice via observation of morphogical and histological changes. Skin aging was induced by UVB irradiation and application of squalene monohydroperoxide (Sq-OOH) to the back skin of hairless mice for six weeks. And, at the same time, saline (C), jojoba oil (VC), PCWE (E), and 0.01% retinoic acid diluted with polyethylene glycol (PC) were applied topically twice per day, six days per week, for a period of six weeks. Improved wrinkle formation in a pattern of shallow furrows and thin and narrow crests was observed in the retinoic acid and PCWE application groups, compared to the C group. On the morphologic analysis for skin wrinkles, the E group showed lower levels in skin roughness, maximum roughness, average roughness, smoothness depth, and arithmetic average roughness by 13.1, 17.2, 18.4, 15.4, and 16.1%, respectively, compared with the C group, indicating that PCWE inhibited potential formation of wrinkles in the skin. In the C group, structures of lipid lamellae and collagen fibers were broken or deformed with an irregular arrangement. Application of retinoic acid and PCWE protected against the deformity of lipid lamellae and collagen fibers. Elastic fibers in dermis of the C group also showed severe transformation; however, applications of retinoic acid and PCWE resulted in a significant decrease in the number of denatured elastic fibers. Therefore, PCWE could have an alleviating effect on skin aging induced by UVB irradiation and application of Sq-OOH.
        4,300원
        4.
        2011.10 구독 인증기관·개인회원 무료
        Several human leukocyte subsets including natural killer (NK) cells, cytotoxic T lymphocytes (CTL), and polymorphonuclear neutrophils (PMN) participate in cellular immune responses directed against vascularized pig-to-human xenografts. As these leukocytes express the death receptor Fas either constitutively (PMN) or upon activation (NK, CTL), we explored in vitro whether the transgenic expression of membrane-bound human Fas ligand (mFasL) on porcine fetal fibroblasts is a valuable strategy to protect porcine xenografts. cDNA of mFasL carrying the deletion at the cleavage site with metalloproteinase and lacking the death domain in its cytoplasmic tail was subcloned into pCAGGS expression vector driven by the chicken β-actin promoter containing blastidin- resistance cassette. The mFasL expression vector was transfected into mini-pig fetal fibroblasts by lipofection method. Blastidin-resistant cells were screened by PCR and FISH. The expression of mFasL was confirmed by Western blot and FACS with the mouse anti-human FasL antibody. Interaction of two transgenic clonal cell lines with human leukocytes was analyzed using functional assay for cytotoxicity. mFasL expressed on porcine fetal fibroblasts protected porcine fetal fibroblasts against killing mediated by human NK cells. The rate of NK cell mediated cytotoxicity was significantly reduced in transgenic clonal cells (54±10.80%) compared to normal minipig fetal fibroblasts. This result indicated that grafts of transgenic pigs expressing mFasL could control the cellular immune response to xenografts, and create a window of opportunity to facilitate xenograft survival.
        5.
        2011.10 구독 인증기관·개인회원 무료
        Pigs may be considered as a suitable organ source for its characteristics in xenotransplantation if significant immunological barriers can be overcome. However, xenograft could be rejected by T cells, especially CD8+ cytotoxic T lymphocytes (CTL)-mediated response, because these elements show great cytotoxicity against xenograft by recognizing Swine Leukocyte Antigen (SLA)-I. Human cytomegalovirus (HCMV) encodes unique short (US) 11 gene, which interferes with cellular immune responses by inducing rapid degradation of newly synthesized heavy chains (HC) of MHC class I from endoplasmic reticulum (ER) to the cytosol. In this study we established two US11 clonal cell lines by transfection into minipig fetal fibroblasts and confirmed the integration of US11 gene by PCR and FISH. The reduction of Swine Leukocyte Antigen (SLA)-I which was expressed on the cell surface by US11 was also detected by flow cytometry assay. The level (14.6 % to 21.2%) of SLA-I expression in US11 clonal cell lines was decreased relative to the control. The reconstructed embryos were produced with these clonal cells and transferred to nine surrogate gilts. Ultrasound examination of recipient surrogates on days 35 after embryo transfer confirmed established pregnancies in two recipients. One recipient delivered one piglet with normal birth weight. PCR analysis revealed that transgene vector was integrated in the offspring genome. Transgene-expression analysis and CTL assay are currently underway. The present results show that transgenic pig was produced with US11 cDNA for controlling cell-mediated rejection. This result indicated that grafts of transgenic pigs expressing human cytomegalovirus protein US11 could control the cellular immune response to xenografts, and create a window of opportunity to facilitate xenograft survival. This research was supported by the BioGreen 21 Program (#20110301-061-541- 001-05-00), Rural Development Administration, Republic of Korea.
        7.
        1995.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The HII region S140 and the associated molecular cloud L1204 have been observed with 10 molecular transitions, CO (1-0), 13CO (1-0), C18O (1-0), CS (2-1), HCO+ (1-0), HCN (1-0), SO (22-11), SO2(220-313), OCS (8-7), and HNCO (404-303) with ~ 50" angular resolutions. More than 7,000 spectra were obtained in total. The morphology of this region shows a massive fragment (the S140 core) and the extended envelope to the northeast. Several gas condensations have been identified in the envelope, having masses of ~103M⊙ and gas number densities of ≾104cm-3 to 3×105cm-3 in their cores. The column densities of the observed molecular species toward the S140 core appear to be the typical warm clouds' abundances. It seems to be that the S140 core and L1204 have been swept up by an expanding shell called the Cepheus bubble. The large value of LIR(embedded stars)/Mcloud ~5 L⊙/M⊙ of the S140 core may suggest that the star formation has been stimulated by the HII region, but the shock velocity and the pressure of the region seem to give a hint of the spontaneous star formation by the self gravity.
        4,000원
        8.
        2015.02 KCI 등재 서비스 종료(열람 제한)
        온주밀감 60품종에 대하여 착색 개시기에 과즙의 플라보노 이드 조성 및 함량을 분석하고 품종들과의 연관관계를 조사하 였다. 온주밀감 과즙에서는 flavanones에 속하는 narirutin, hesperidin과, flavones인 rutin, polymethoxylated flavones 인 sinensetin, tangeretin, nobiletin 등 6종을 함유하고 있는 것으로 나타났다. 온주밀감 과즙 중에는 narirutin, hesperidin 함량이 가장 높아 대표적인 기능성 성분으로 나타났으며, 기능 성이 우수한 polymethoxylated flavones인 sinensetin, tangeretin, nobiletin도 함유하고 있었다. Hesperidin 함량 범위는 41~196 ㎎/L로, narirutin 함량은 25~230 ㎎/L로 나타났다. Rutin 함 량은 평균 2.2 ㎎/L로 미량이 검출되었고 일부 품종에서는 전혀 검출이 이루어지지 않았다. 감귤에 특이적으로 나타나는 polymethoxylated flavones류인 sinensetin, nobiletin, tangeretin 은 미량이지만 모든 품종에서 검출되었다. 온주밀감 과즙 중에 함유된 플라보노이드 조성 및 함량과 품종의 수확기와의 연관 성을 분석하고자 R 프로그램으로 계층적 군집분석을 실시한 결 과, 플라보노이드 성분별 함량에 따라 A, B1, B2 집단으로 구분 할 수 있었으나 세집단 모두에서 극조생온주밀감, 조생온주밀 감, 보통온주밀감이 산재하여 있어 착색개시기 과즙 중 플라보 노이드 분포와 과실의 성숙기와는 관련성이 적은 것으로 나타 났다.