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        검색결과 97

        81.
        2015.06 KCI 등재 서비스 종료(열람 제한)
        기계 또는 소프트웨어 프로그램과 같은 인공물은 단순히 도구일 뿐인가? 이미 많은 프로그램들이 인간사용자들을 안내하거나 도와주는 일을 하고 있다. 본 연구에서는 행위자(agents) 개념을 사용하여, 인간플레이어와 게임봇의 행위성에 대해 살펴볼 것이다. 게임봇은 상호작용성과 자율성은 물론이고 적응성의 단계에 진입하고 있다. 게임수행 동안, 게임봇과 인간플레이어는 서로를 구성하는 사이보그 동료이다. 그런 점에서 게임봇은 정치사회적 존재가 되고 있다. 컴퓨터 환경에서 인간행위자는 인공행위자와의 관계에서 구성되는 사이보그적 존재가 되므로, 그들은 전통적인 인간행위자와는 다르다.
        83.
        2013.12 KCI 등재 서비스 종료(열람 제한)
        TCR subunits are members of membrane-bound receptors which allow the fast and efficient elimination of the specific fish pathogens have regulated function in adaptive immunity. Sequence structure of TCR subunits have been reported for various teleosts, but the information of each TCR subunit functional characterization through expression analysis in fish was unknown. In this study, we examined the gene expression of TCR subunits in the early developmental stages and observed transcript levels in various tissues from healthy adult olive flounder by RT-PCR. The mRNA expression of alpha subunit was already detected in the previous hatching step. But the transcripts of another TCR subunit were not observed during embryo development and increased after hatching and maintained until metamorphosis at the same level. It was found that all TCR subunits mRNAs are commonly expressed in the immune-related organ such as spleen, kidney and gill, also weak expressed in fin and eye. TCR alpha and beta subunit were expressed in brain, whereas gamma and delta were not expressed same tissue. The sequence alignment analysis shows that there are more than 80% sequence homology between TCR subunits. Because it has a high similarity of amino acid sequence to expect similar in function, but expression analysis show that will have may functional diversity due to different time and place of expression.
        84.
        2013.12 KCI 등재 서비스 종료(열람 제한)
        The innate immune system is the only defense weapon that invertebrates have, and it is the fundamental defense mechanism for fish. The innate immune response is important in newly hatched flounders because it is closely involved in the initial feeding phase, which is why it is essential for survival during the juvenile period. The expression analysis of genes involved in the innate immune response in the olive flounder (Paralichthys olivaceus) in the days after hatching is incomplete. Therefore, we have begun to examine the expression patterns of genes specifically induced during the development of the innate immune system in newly hatched flounders. Microscopic observation showed that pronephron formation corresponded with the expression of perforin-encoding gene. These results suggest that perforin plays a vital role in the innate immunity of the kidney during developmental stages. Perforin expression was strong at the start of the development of the innate immune response, and continued throughout all the development stages. Our findings have important implications with respect to perforin’s biological role and the evolution of the first defense mechanisms in olive flounder. Further studies are required to elucidate the perforin-mediated innate immunity response and to decipher the functional role of perforin in developmental stages.
        85.
        2013.12 KCI 등재 서비스 종료(열람 제한)
        Fish larvae are immediately exposed to microbes from hatching to maturation of their lymphoid organs, therefore effective innate mechanisms is very important for survival in such an environment. The key component of innate immune system, C3 is central protein of all activation pathways of the complement system, leading to inflammatory reactions, such as opsonisation, chemotaxis, and cell lysis of pathogens. Although, innate mechanisms is essential for survival in the early stage of development, little is known about defence mechanisms. In this study, the alignment analysis showed that amino acid sequence of C3 from olive flounder liver EST homologous to other known C3 sequences with 73-99% identity. Also, we examined the tissue distribution of olive flounder C3 and analyzed expression pattern from the fertilized egg until 28 days post hatching. As a result, olive flounder C3 mRNA was expressed only in the liver and the mRNA level more increased as developmental proceed during the early stage. These results may suggest that olive flounder C3 plays an important function in the early immune response of olive flounder larvae.
        86.
        2013.08 서비스 종료(열람 제한)
        For the study of population genetic structure with mtDNA, it is essential to measure genetic diversity at each mtDNA regions. Also, to evaluate the variation according to the each region should follow as well as to see if there are differences. In this study, we delved into the variations and dendrogram among samples of seven mtDNA regions (NDⅡ, NDⅤ, NDⅣ, NDⅣL, NDⅥ, NDⅠ, 12SrRNA) from wild Pacific abalone, Haliotis discus hannai collected in Yeosu, Korea. The region with the highest genetic variation was NDⅣ region (Haplotype diversity = 1.0000, Nucleotide diversity = 0.010823) with two to five times higher variation than the others. Furthermore, the study to see if there is a difference between the regions of samples showed that similar aspects of dendrogram in NDⅡ and NDⅠ(divergence of 90% and 87%), which forms a group with hd4, 7, 8 and 10 at bootstrap support, based on 1000 replications. Also, pair-wise FST between clusters within the regions showed high values; 0.4061 (P=0.0000), 0.4805 (P=0.0000) respectively. Therefore we can infer that it is the most efficient and accurate way to analyze the region of NDⅣ with the highest variation in addition to the regions of NDⅡ and NDⅠ, which formed clusters with high bootstrap value, for study of population genetic structure in this species.
        87.
        2013.07 서비스 종료(열람 제한)
        Soybean [Glycine max (L.) Merrill] is one of the world’s most major crops as not only an important source of oil and protein, but also secondary metabolites. Intake of soybean is associated with decreased risk of cardiovascular disease and osteoporosis, as well as cancer, including breast and colon cancers. Seventy soybeans germplasms collected from 4 different countries, America (6 varieties), China (15 varieties), Japan (16 varieties), and Korea (33 varieties), were distributed by Chungbuk National University (Cheongju, Chungbuk, Korea) and cultivated in Konkuk University farm. This study investigated the isoflavones in seventy soybeans according to 4 different origins (America, China, Japan and Korea). Between 4 different origins, Korea showed highest concentrations of total isoflavones (1292.6 ± 438.6 ㎍ g-1) and China showed the lowest concentrations of total isoflavones (843.8 ± 365.7 ㎍ g-1). The total isoflavone contents in soybean of America and China ranged from 572.3 ㎍ g-1 to 2001.9 ㎍ g-1 and from 275.8 ㎍ g-1 to 1521.8 ㎍ g-1, respectively. And the isoflavone contents of Japan and Korea ranged from 473.3 ㎍ g-1 to 2314.6 ㎍ g-1 and from 419.0 ㎍ g-1 to 3010.7 ㎍ g-1, respectively. Malonylgenistin (356.9 ± 158.8 ㎍ g-1) was the major isoflavones among 12 isoflavones. Specially, glycoside and malonylglycosides constituted 49.2 % and 45.3 % of total isoflavones in soybeans, respectively.
        89.
        2012.12 KCI 등재 서비스 종료(열람 제한)
        Manganese () is a trace element that is essential for normal physiology, and is predominantly obtained from food. Several lines of evidence, however, demonstrated that overexposure to exerts serious neurotoxicity, immunotoxicity and developmental toxicity, particularly in male. The present study aimed to evaluate the effect of 0, 1.0, 3.3, and 10 mg/kg/day doses of on the reproductive organs in the immature female rats. Rats (PND 22; S.D. strain) were exposed to () dissolved in drinking water for 2 weeks. The animals were sacrificed on PND 35, then the tissues were immediately removed and weighed. Histological studies were performed using the uteri tissue samples. Serum LH and FSH levels were measured with the specific ELISA kits. Body weights of the experimental group animals were not significantly different from those of control group animals. However, ovarian tissue weights in 1 mg and 3.3 mg dose groups were significantly lower than those of control animals (p<0.05 and p<0.01, respectively). Uterine tissue weights of 3.3 mg dose groups were significantly lower than those of control animals (p<0.01), while the 1 mg dose and 10 mg dose failed to induce any change in uterine weight. Similarly, only 3.3 mg dose could induce the significant decrease in the oviduct weight compared to the control group (p<0.05). Non-reproductive tissues such as adrenal and kidney failed to respond to all doses of exposure. The uterine histology revealed that the exposure could affect the myometrial cell proliferation particularly in 3.3 mg dose and 10mg dose group. Serum FSH levels were significantly decreased in 1mg dose and 10 mg groups (p<0.05 and p<0.01, respectively). In contrast, treatment with 1 mg dose induced a significant increment of serum LH level (p<0.05). The present study demonstrated that exposure is capable of inducing abnormal development of reproductive tissues, at least to some extent, and altered gonadotropin secretions in immature female rats. Combined with the well-defined actions of this metal on GnRH and prolactin secretion, one can suggest the might be a potential environmental mediator which is involved in the female pubertal process.
        90.
        2011.09 서비스 종료(열람 제한)
        Estrogens are ubiquitous signaling molecules that influence nearly every cell type, and exert profound effects on embryonic development, and differentiation. Wnt pathway, which recruits β-catenin into nuclei, and activates The Wnt-dependent transcription factors, also plays an important role in embryonic development and stem cell maintenance, and differentiation. Accumulating evidences indicate that potential convergence between these two pathways in carcinoma cells. However, physiological roles of estrogens in development and differentiation of human embryonic stem cells (hESCs) are relatively unknown. Here, we demonstrated that estrogenic compounds 17α-ethinylestradiol (EE2) and genistein (GEN) significantly increased β-catenin expression in undifferentiated hESCs cultured in feeder-free media. Interestingly, GEN treatement induced an increased trend of mesendodermal gene expressions, and significantly inhibited ectodermal gene expressions (Nestin and Pax6) in embrioid body (EB). Expectantly, GEN increased epithelial-mesenchymal transition (EMT) related gene expression (Snail2, and Twist), whereas decreased E-cadherin on day 6 of EB development. Taken together, these suggest that estrogens may in part the powerful effects on normal hESC differentiation. Mechanistic studies of estrogen signaling continue to suggest novel drug targets for stem cells and will also improve screening methods of developmental toxicity.
        91.
        2011.09 서비스 종료(열람 제한)
        We previously reported that purified hepatocyte-like cells derived from human embryonic stem cell (hESC) promoted the liver tissue recovery not only by cell replacement, but also by delivering proteins (secretome) that enhance endogenous host liver regeneration. In this study, we investigated possible therapeutic effects of secretomes obtained from undifferentiated hESC and mesenchymal stem cell (hMSC), and explored the underlying mechanism in a mouse model of chronic liver injury. Mice pre-intoxicated with dimethylnitrosamine (DMN) were treated with single intraperitoneal injection of secretome or medium used to support the growth of hESCs or hMSCs. Both hESC- and MSC-secretomes induced robust host liver regeneration, as determined by biochemical and histological analyses. The expression of MMP2 was significantly increased in the liver that received hESC- or hMSC-secretome, compared to control groups. In contrast, expression of α-SMA, a hallmark of activated hepatic stellate cells, was profoundly decreased after administration of both secretomes. These results suggest that hESCs and MSCs may release soluble factors that support the host tissue regeneration of chronically injured liver.
        93.
        2007.12 KCI 등재 서비스 종료(열람 제한)
        1972년부터 2007년까지 발표된 난 관련 석ㆍ박사 학위논문 130편을 분석하여 연구동향을 살펴본 결과는 다음과 같다.1. 연도별 분석결과, 1972년부터 2007년까지 130편의 논문이 발표되었는데, 1972년 처음 논문이 발표된 이후 차차 논문의 발표 수가 증가하기 시작하였으며, 1990년대에 이르러서 발표논문이 급격한 증가 추세를 보였다.2. 학위별, 학교별로 발표된 동향을 살펴보면 전체 학위 논문 중 석사학위 논문이 102편으로 전체의 78.5%인 반면, 박사학위 논문은 28편으로 전체의 21.5%에 불과하다. 학교별 분류에 있어서 논문 발표 빈도는 제주대가 16.9%, 서울여대가 13.1%, 고려대와 경북대가 각각 8%순이었다. 3. 난의 종류별로는 자생란 연구가 전체 연구의 41.5%로 다른 종류에 비해 높게 나타났으며, 연구 분야별로는 번식관련 논문이 45편으로 전체의 34.6%로 가장 많았고, 다음으로는 재배관련 논문이 22편으로 전체의 16.9%를 차지하였다. 번식과 재배관련 논문은 1972년 난 관련 논문이 발표된 이래로 꾸준히 발표되고 있으며 특히 2000년대 초반에는 가장 많은 관련 논문을 발표한 것으로 나타났다.
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