• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집A
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• pp.778-782
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• 2000

Deep drawing and ironing are the major process used today in manufacturing of battery case used in cellular phone and IMT-2000 from aluminum. The same technology is utilized in manufacturing of steel or aluminum rectangular cans for components of medical instrument, portable PC, walkman and so on. Most of these processes require multi-stage ironing following the deep drawing and redrawing processes. The practical aspects of this technology are well known and gained through extensive experiment and production know-how. However, the fundamental aspects of theses processes are relatively less known. Thus, it is expected that process simulations using FEM techniques would provide additional detailed information that could be utilized to improve the process condition. This paper illustrates the application of process modeling to deep drawing and redrawing operations with the cellular phone and IMT-2000. A commercially avaliable finite element code LS-DYNA3D was used to simulate deep drawing and redrawing operations.

• Molecular & Cellular Toxicology
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• 제4권4호
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• pp.285-292
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• 2008

Crocin is one of the major components of gardenia fruit and saffron which are widely used as natural food colorants and as traditional Chinese medicines. However, the genotoxicity data on crocin are not sufficient for safety evaluation. The purpose of this study was the examination of the genotoxicity on crocin from gardenia yellow in bacterial and mammalian cells, using various genotoxic battery testing assays and the influence of crocin on methyl methanesulfonate (MMS) and ${H_2}{O_2}$-induced DNA damage in vitro, using single cell gel electrophoresis (comet) assay. From results, no considerable mutagenicity and clastogenicity were seen in bacteria and mammalian cells treated with crocin, by Ames test, chromosomal aberration assay, ${tk}^{+/-}$ gene forward mutation assay and comet assay. And, post-treatment with crocin significantly suppressed ${H_2}{O_2}$-induced DNA damage in a dose-dependent manner. In conclusion, the findings of the present study and other previous observations indicate that crocin has no genotoxic potential. And it showed that crocin clearly repressed the genotoxic potency of ${H_2}{O_2}$. These results suggest that anti-oxidative effects of crocin may be involved in the protective effects of DNA damage.

• Journal of Ginseng Research
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• 제22권1호
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• pp.60-65
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• 1998

The effect of Korean red-ginseng extract on the proliferation and cellular activity of mouse B and T lymphocytes was examined in vitro. Both water and ethanol extract from red-ginseng increased the growth of normal B and T lymphocytes 1.5∼2.5-folds. Saponin and polysaccharide fractions from ginseng extract also stimulated the proliferation of normal lymphocytes much higher than several well-known immunostimulators. B and T lymphoma cell lines responded to the ginseng extract and fractions by growth, too, while non-lymphoid cell lines did not. Immunoglobulin production of unprimed B-lymphocytes was little affected by the ginseng extract and fractions, though the ethanol extract slightly enhanced Ini, production of B-lymphocytes. When cytolytic activity of T lymphocytes against tumor tells was induced in vitro, both of the saponin and polysaccharide fractions and the ginseng ethanol extract increased the cellular activity of cytotoxic T lymphocytes 4-5-folds, while the ginseng water extract did not. Especially, the saponin fraction exhibited 10-times higher stimulatory effect on the cytolytlc activity of cytotoxic T cells than the ethanol extract and the pclysaccharide fraction did. These results suggest that Korean red-ginseng contain potent immunomodulating components to stimulate the proliferation of B and T lymphocytes and the cellular activity of cytotoxic T lymphocytes.

• Molecules and Cells
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• 제39권6호
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• pp.484-494
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• 2016

Plant cells have a remarkable ability to induce pluripotent cell masses and regenerate whole plant organs under the appropriate culture conditions. Although the in vitro regeneration system is widely applied to manipulate agronomic traits, an understanding of the molecular mechanisms underlying callus formation is starting to emerge. Here, we performed genome-wide transcriptome profiling of wild-type leaves and leaf explant-derived calli for comparison and identified 10,405 differentially expressed genes (> two-fold change). In addition to the well-defined signaling pathways involved in callus formation, we uncovered additional biological processes that may contribute to robust cellular dedifferentiation. Particular emphasis is placed on molecular components involved in leaf development, circadian clock, stress and hormone signaling, carbohydrate metabolism, and chromatin organization. Genetic and pharmacological analyses further supported that homeostasis of clock activity and stress signaling is crucial for proper callus induction. In addition, gibberellic acid (GA) and brassinosteroid (BR) signaling also participates in intricate cellular reprogramming. Collectively, our findings indicate that multiple signaling pathways are intertwined to allow reversible transition of cellular differentiation and dedifferentiation.

• 산학경영연구
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• 제17권2호
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• pp.203-228
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• 2004

이 논문은 IT서비스의 품질평가 모델을 개발하는 것을 목적으로 한다. 접근방법은 이동통신 서비스(휴대폰)의 품질평가 요소들을 중심으로 조사연구를 하였다. 오늘날 이동통신 서비스 산업은 날로 발전하고 있고 소비자 역시 새로운 제품품질에 대한 욕구가 다양화되고 있어 다기능, 다매체서비스, 고속데이터 전달서비스 등 다양한 부가서비스의 새로운 경쟁시대에 직면하고 있다. 이 연구에서 얻어진 결과는 이동통신 서비스의 전반적인 품질 결정요인으로 (1) 통화품질, (2) 휴대폰단말기, (3) 지원서비스, (4) 부가서비스, (5) 지원시설 및 설비, (6) 비용이 유의한 영향을 미치고 있고, 이동통신 서비스의 본원적 기능인 통화품질에 추가하여 휴대폰 단말기와 부가서비스들이 중요한 영향을 미치는 것으로 나타났다. 한편 휴대폰 단말기와 부가서비스 요소는 이동통신 서비스의 전반적 품질결정에 직접적으로 영향을 미칠 뿐만 아니라, 고객만족에도 직접적으로 영향을 미치는 요소로 확인되었다. 이는 소비자들이 직접 휴대하고 이용하는 단말기와 부가서비스가 매우 중요하다는 사실을 다시 한 번 확인해주는 것으로 보인다.

• 한국식물학회:학술대회논문집
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• 한국식물학회 2002년도 춘계학술발표대회:발표눈문요지록
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• pp.38-61
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• 2002

• Journal of Microbiology
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• 제34권3호
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• pp.225-228
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• 1996

The cellular fatty acid methyl esters (FAMEs) analysis data obtained for clusters defined at a Euclidian distance of 17.5, in the classification of lactic acid bacteria isolated from kimchi, described by Lee et al. (4), was used for the identification of 79 Leuconostoc isolates. The test strains were isolated using a selective isolation medium specific for the genus Leuconostoc. These strains were then characterized according to their fatty acid profiles. The results show that all seventy nine test strains were identified to the known Leuconostoc clusters B, C, and D. Cluster B had the highest relative amount of the saturated fatty acid 16 : 0. The saturated fatty acid 16 : 0 and summed feature 9 were found as a major components in cluster C, which had a higher level of summed feature 9 than cluster B. Cluster D is characterized by the highest relative amount of the unsaturated fatty acid 18 : 1 w9c. It is suggested that FAMEs analysis can be successfully applied in the identification of lactic acid bacteria isolated from kimchi.

• Molecules and Cells
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• 제27권5호
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• pp.533-538
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• 2009

Heat shock protein 27 (Hsp27) is a molecular chaperone protein which regulates cell apoptosis by interacting directly with the caspase activation components in the apoptotic pathways. With the assistance of the Tat protein transduction domain we directly delivered the Hsp27 into the myocardial cell line, H9c2 and demonstrate that this protein can reverse hypoxia-induced apoptosis of cells. In order to characterize the contribution of Hsp27 in blocking the two major apoptotic pathways operational within cells, we exposed H9c2 cells to staurosporine and cobalt chloride, agents that induce mitochondria-dependent (intrinsic) and -independent (extrinsic) pathways of apoptosis in cells respectively. The Tat-Hsp27 fusion protein showed a greater propensity to inhibit the effect induced by the cobalt chloride treatment. These data suggest that the Hsp27 predominantly exerts its protective effect by interfering with the components of the extrinsic pathway of apoptosis.

• 대한세포병리학회지
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• 제7권2호
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• pp.218-224
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• 1996

We describe two cases of metastatic Wilms' tumor in the lung with emphasis on the cytologic features of specimens obtained by needle aspiration. One of them was extrarenal Wilms' tumor. The findings were correlated with the histopathologic features of the primary lesion. Cellular components in the fine needle aspiration cytology (FNAC) slides included blastemal, epithelial, stromal and inflammatory cells with immature tubular differentiation and rosette formation. Recognition of these cellular components in FNAC smears help in establishing FNAC diagnosis of Wilms' tumor. The blastemal cells were represented by small to medium sized cells with scanty cytoplasm having ill-defined borders and round to slightly oval nuclei with evenly dispersed chromatin and small marginated nucleoli. They were seen in our two cases. The differential diagnosis includes neuroblastoma, malignant lymphoma, malignant rhabdoid tumor, clear cell sarcoma, Ewing's sarcoma and embryonal rhabdomyosarcoma. In conclusion, making a definite cytologic diagnosis of metastatic Wilms' tumor may be possible by light and electron microscopy and immunohistochemical staining. The above findings may contribute to the diagnosis of FNAC of metastatic Wilms' tumor.

• Molecular & Cellular Toxicology
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• 제3권1호
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• pp.68-75
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• 2007

[ $\alpha$ ]-Terpinene has been known as a repellent against the mosquito Culex pipiens pallens Coquillett based on a human forearm bioassay. $\alpha$-Terpinene showed significantly greater repellency than a commercial formulation, N, N-diethyl-m-methylbenzamide (deet). In this study, skin and eye sensitivity of $\alpha$-terpinene (2%) was examined with bioassays using white New Zealand rabbits. There were somewhat gross and histological changes observed in these treatments. Eye irritancy assays examined gross changes to cornea, iris and conjuctiva, and histological changes to smear of ocular discharge and eye tissue. Treated rabbits were divided into two cohorts, a saline washed cohort (W) or a non-washed cohort (NW). Opacity of cornea and redness, chemosis and discharge of conjuctiva were observed in both cohorts, but disappeared within 4 and 10 days in W and NW, respectively. Main components of ocular discharges were fibrin, epithelial or epitheloid cells, lymphoid cells, erythrocytes and granulocytes. These abnormal cellular components disappeared within 4 days and 10 days in W and NW, respectively. No permanent histological differences were observed between the two cohorts. However, severe irritation was determined as 57.2 of I.I.O.I value on the first day after treatment. These findings indicate a spray-type solution containing 2% $\alpha$-terpinene may serve as an alternative mosquito repellent and further studies need to reduce the eye irritation with formulation changes.