• Korean Journal of Microbiology
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• v.46 no.1
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• pp.96-103
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• 2010

Oligosaccharyltransferase (OTase) catalyzes the transfer of a lipid-linked oligosaccharide (LLO) to the nascent polypeptide. Most eukaryotes have an OTase composed of a multisubunit protein complex. However, the kinetoplastid Leishmania major and the bacterium Campylobacter jejuni have only a single subunit for OTase activity, Stt3p and PglB, respectively. In this study, a new in vitro assay for OTase was developed by using a fluorescent peptide containing N-glycosylation sequon, Asn-Xaa-Thr/Ser, where Xaa can be any amino acid residue except Pro. L. major Stt3p and C. jejuni PglB as a model OTase enzyme demonstrated the formation of glycopeptides from a fluorescent peptide through OTase activities. For separation and measurement of the glycopeptides produced by the OTases, Tricine-SDS-PAGE, a lectin column and fluorospectrophotometer, and HPLC were applied. Comparison of these assay methods for analyzing a fluorescent glycopeptide showed HPLC analysis is the best method for separation of glycopeptides and nonglycosylated peptides as well as for quantify the peptides than other methods.

• The Korean Journal of Zoology
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• v.39 no.3
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• pp.239-247
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• 1996

An embryonic stem (ES) cell-based in vitro model system was examined to determine whether a simple differentiation of embryoid bodies (EB) in the suspension medium is useful to dissect early erythropoiesis. Characteristics of the differentiating EBs were monitored for their differentiation potential to generate hematopoietic cell types by general morphology, benzidine staining and two-step colony assays, and expressivity of several erythroid marker genes by the RT-PCR analysis for total cellular RNA prepared from the differentiating EBs. Every ematopoietic lineage cells were generated from the differentiating EBs with reproducible frequencies, similar to the other sophisticated differentiation protocols. Furthermore, the globin gene switching in differentiating ES cells paralleled the sequence of events found in the mouse embryo, and such that their expression was activated by at least 12 hrs later than those of erythroid-specific transcription factors, GATA-1 and Tal-1 The erythropoietic differentiation program initiated reproducibly and efficiently in this simple differentiation system in a suspension culture, such that this system may be useful for dissection of the molecular events of early erythropoiesis.

• Journal of Korea Multimedia Society
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• v.6 no.1
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• pp.136-147
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• 2003

To achieve an optimal performance for a given problem, we need an integrative process of the parameter optimization via learning and the structure optimization via model selection. In this paper, we propose an efficient optimization method for improving generalization performance by considering the property of each sub-method and by combining them with common theoretical properties. First, weight parameters are optimized by natural gradient teaming with adaptive regularization, which uses a diverse error function. Second, the network structure is optimized by eliminating unnecessary parameters with natural pruning. Through iterating these processes, candidate models are constructed and evaluated based on the Bayesian Information Criterion so that an optimal one is finally selected. Through computational experiments on benchmark problems, we confirm the weight parameter and structure optimization performance of the proposed method.

• Journal of the Korean Institute of Navigation
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• v.24 no.5
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• pp.343-360
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• 2000

The information technology(IT) development of telecommunication, along with the informationalization over the world, enables the firms to process their inner and outer operations through Electronic Data Interchange (EDI) system. And the concept of logistics has become more important to the enterprises in strategic sense because it had aggrandized itself to more comprehensive and integrative concept. Also the world shipping market is more competitive than any other market. In these environment, to maintain competitve power, shipping firms process operations by Logistics Information system(LIS), And then, reduce the working processes, working time and its costs. So the LIS has become more important in developing our national logistics system and industry. Therefore, this study purposes on empirically analyzing the activation factors of shipping LIS and the relationship these factors with logistic performances in the shipping industry. Considering environments of Shipping logistics information system, this study sets up the research model and hypothesis to examine the activation factors of shipping LIS and the relationship these factors with logistic performances. We used the field data on the 163 numbers of firms(29 overseas shipping companies and 133 forwarding Agency) to get the empirical evidence. According to the study results, The shipping LIS activation factors which the sample firms recognized as important: were top manager's support, well structured communication channel, strategic plan's connection and inner informationalization level. And IS organization ＆ human resources, IS discipline ＆ training, software development, IS organizational alignment, database management system, information standardization, competitive advantage, financial support and government support represent partially significant. Also, the current shipping LIS's main problems are expensive system cost, standardization of working process's, institution's imperfection and system's interaction defect. So these problems must be improved to activate shipping LIS.

• Journal of the Korean Institute of Navigation
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• v.25 no.2
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• pp.159-172
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• 2001

The information technology(IT) development of telecommunication, along with the information analyzation over the world, enables the firms to process their inner and outer operations through Electronic Data Interchange (EDI) system. And the concept of logistics has become more important to the enterprises in strategic sense because it had aggrandized itself to more comprehensive and integrative concept. Also the world shipping market is more competitive than any other market. In these environment, to maintain competitive power, shipping firms process operations by Logistics Information system(LIS), And then, reduce the working processes, working time and its costs. So the LIS has become more important in developing our national logistics system and industry. Therefore, this study purposes on empirically analyzing the activation factors of shipping LIS and the relationship these, factors with logistic performances in the shipping industry. Considering environments of Shipping logistics information system, this study sets up the research model and hypothesis to examine the activation factors of shipping LIS and the relationship these factors with logistic performances. We used the field data on the 163 numbers of firms(29 overseas shipping companies and 133 forwarding Agency) to get the empirical evidence. According to the study results, The shipping LIS activation factors which the sample firms recognized as important: were top managers support, well structured communication channel, strategic plans connection and inner information analyzation level. And IS organization & human resources, IS discipline & training, software development, IS organizational alignment, database management system, information standardization, competitive advantage, financial support and government support represent partially significant. Also, the current shipping LISs main problems are expensive system cost, standardization of working processs, institutions imperfection and systems interaction defect. So these problems must be improved to activate shipping LIS.

• The Korean Journal of Zoology
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• v.18 no.1
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• pp.9-18
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• 1975

Male rats of Sprague-Dawley strain were subjected to low atmospheric pressures (500 and 300 mmHg)for an hour a day during 15 days. The serum protein patterns and the level of total serum proteins were determined at various time intervals during exposure. 1. When compared with control animals maintained at 760 mmHg, the low atmospheric pressure-exposed animal groups at 500 or 380 mmHg showed different changes in the serum protein patterns and the level of total serum proteins. 2. In the level of total serum preteins, a decrease resulted during the 1st day exposure of both groups, and slowly increased thereafter. From 5 to 15 days a higher steady state value than the control was obaserved. 3. In A/G ratio, the sera resulted in an increase in 1st day of both groups, and slowly decreased thereafter. From 5 to 15 days a lower steady state significantly than control value resulted. 4. Specifically, in the serum protein components, $\\beta$-globulin was increased during the experimental periods of both groups.

• Animal cells and systems
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• v.9 no.2
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• pp.79-85
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• 2005

Oxidized abasic residues arise as a major class of DNA damage by a variety of agents involving free radical attack and oxidation of deoxyribose sugar components. 2-deoxyribonolactone (dL) is a C1'-oxidized abasic lesion implicated in DNA strand scission, mutagenesis, and covalent DNA-protein cross-link (DPC). We show here that mammalian cell-free extract give rise to stable DPC formation that is specifically mediated by dL residue. When a duplex DNA containing dL at the site-specific position was incubated with cell-free extracts of Po ${\beta}-proficient$ and -deficient mouse embryonic fibroblast cells, the formation of major dL-mediated DPC was dependent on the presence of DNA polymerase (Pol) ${\beta}$. Formation of dL-specific DPC was also observed with histones and FEN1 nuclease, although the reactivity in forming dL-mediated DPC was significantly higher with Pol ${\beta}$ than with histones or FEN1. DNA repair assay with a defined DPC revealed that the dL lesion once cross-linked with Pol ${\beta}$ was resistant to nucleotide excision repair activity of cell-free extract. Analysis of nucleotide excision repair utilizing a model DNA substrate containing a (6-4) photoproduct suggested that excision process for DPC was inhibited because of DNA single-strand incision at 5' of the lesion. Consequently DPC mediated by dL lesion may not be readily repaired by DNA excision repair pathway but instead function as unusual DNA damage causing a prolonged DNA strand break and trapping of the major base excision repair enzyme.

• Preventive Nutrition and Food Science
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• v.18 no.1
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• pp.18-22
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• 2013

To investigate radical scavenging effects and protective activities of bitter melon (Momordica charantia) against oxidative stress, in vitro and a cellular system using LLC-$PK_1$ renal epithelial cells were used in this study. The butanol (BuOH) fraction of bitter melon scavenged 63.4% and 87.1% of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals at concentrations of 250 and $500{\mu}g/mL$, respectively. In addition, the BuOH fraction of bitter melon effectively scavenged hydroxyl radicals (${\cdot}OH$). At all concentrations tested, the scavenging activity of the BuOH fraction was more potent than that of the positive control, ascorbic acid. Furthermore, under the LLC-$PK_1$ cellular model, the cells showed a decline in viability and an increase in lipid peroxidation through oxidative stress induced by pyrogallol, a generator of superoxide anion ($O_2{^-}$). However, the BuOH fraction of bitter melon significantly and dose-dependently inhibited cytotoxicity. In addition, 3-morpholinosydnonimine (SIN-1), a generator of peroxynitrite ($ONOO^-$) formed by simultaneous releases of nitric oxide and $O_2{^-}$, caused cytotoxicity in the LLC-$PK_1$ cells while the BuOH fraction of bitter melon ameliorated oxidative damage induced by $ONOO^-$. These results indicate that BuOH fraction of bitter melon has protective activities against oxidative damage induced by free radicals.

• Journal of Global Scholars of Marketing Science
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• v.15 no.3
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• pp.93-116
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• 2005

This study explored factors affecting consumer's external information search effort on online shopping malls through three approaches(cost-benefit approach, psychological motivation approach, and web-site theory approach) respectively, and designed the integrative model through searching the relationships among them. In this study search motivation are designed to be explained by search benefit and search cost that are explained by factors related to the web site and search efforts are designed to be explained by search benefit, search cost and search motivation. The results from our empirical research showed that search motivation, search benefits and prior knowledge on online shopping malls have a direct effect on consumer external information search effort. On the other hand, it was verified that the search motivation was affected by search benefits and purchase involvement, and the search benefits are directly influenced by purchase involvement, constructive simplicity, search convenience and trust. In addition, purchase involvement, time press, constructive simplicity and search convenience had direct effects on the search cost.

• Child Health Nursing Research
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• v.21 no.2
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• pp.83-90
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• 2015

Purpose: The purpose of this study was to describe the subjective happiness and satisfaction with life of children with type 1 diabetes and explore related factors. Methods: A descriptive cross-sectional study design was used and the study was conducted with children at a diabetes camp. Data were collected using a self-report questionnaire to explore positive and negative psychological factors. The questionnaire included Subjective Happiness Scale, Satisfaction with Life Scale, Perceived Stress Scale and the Center for Epidemiological Studies Depression Scale for Children (CES-DC), Multidimensional Scale of Perceived Social Support, and General Self-Efficacy Scale. Results: Data from 15 children were used for data analysis. The correlational analysis results showed that subjective happiness was positively correlated satisfaction with life, social support, and self-efficacy, and was negatively correlated with perceived stress. Satisfaction with life was positively correlated social support, and was negatively correlated with perceived stress. Conclusion: Results indicate that the positive psychology factors were closely related with social support and self-efficacy and may alleviate perceived stress and depressive feelings. Therefore, researchers and clinicians should include positive psychological factors in their health management model for children with chronic illness.