• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2001.05a
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• pp.40-43
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• 2001

The use ef sheet material for the hydroforming of a closed hollow body out of two sheet metal blanks is a new class of hydroforming process. By using a three-dimensional finite element program, called HydroFORM-3D, the hydroforming process of sheet metal pairs is analyzed. Also the comparison of conventional deep-drawing and hydroforming process was conducted. The simulation has concentrated on the influences of the various forming conditions, such as the unwelded or welded sheet metal pairs and friction condition, on the hydroforming process. This computational approach can prevent time-consuming trial-and-error in designing the expensive die sets and hydroforming process of sheet metal pairs.

• Journal of Microbiology and Biotechnology
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• v.11 no.6
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• pp.1111-1114
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• 2001

An extracellular fibrinolytic-enzyme-producing bacterium was isolated from Doen-Jang, a Korean traditional fermented flood, and identified as Bacillus sp. DJ based on its morphology and cellular fatty acid composition. The total extracellular fibrinase (EF) from Bacillus sp. DJ was analyzed using three fibrin zymographic techniques, SDS-fibrin zymography (SDS-FZ), isoelectrofocucing-fibrin zymographs(IEF-FZ), and a two-dimensional SDS-fibrin zymographic analysis (2D SDS-FZ). As a result, the EP map of Bacillus sp. DJ was established. The results suggest that the 2D SDS-FZ method will be a useful tool for the proteomic approach for many other bacterial pretenses.

• Communications for Statistical Applications and Methods
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• v.8 no.3
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• pp.625-632
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• 2001

Principal component analysis(PCA) is a multivariate technique falling under the general title of factor analysis. The purpose of PCA is to Identify the dependence structure behind a multivariate stochastic observation In order to obtain a compact description of it. In engineering field PCA is utilized mainly (or data compression and restoration. In this paper we propose a new robust Hebbian algorithm for robust PCA. This algorithm is based on a hyperbolic tangent function due to Hampel ef al.(1989) which is known to be robust in Statistics. We do two experiments to investigate the performance of the new robust Hebbian learning algorithm for robust PCA.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.10 no.4
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• pp.84-90
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• 2001

The electro-reheoligical(ER) effect refers to the abrupt change in viscosity in certain suspensions on application of an electric field. This paper presents experimental results on material properties of an ER fluids subjected to electrical fatigues. As a first step, two types of EF fluids are made of arabic gum and methyl cellulose(MC) choosing 25% of parti-cle weight-concentration. Following the construction of test mechanism for electrical durability of ER fluid, the dynamic yield shear stress and current density of the ER fluids are experimentally distilled as a function of electric field. The yield shear stress of operated ER fluids are distilled and compared with those of unused ER fluids.

• Journal of the Korea Computer Industry Society
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• v.2 no.12
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• pp.1505-1516
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• 2001

The goal of Medical multimedia server is to develop computer hardware and software which would enable electronic access, storage, transmission, and display of patient data and images. Since the current network only provides so called "best-effort" services, it is impossible to satisfy QoS guarantee that is required for real time application services for emergency room, operating room etc. Accordingly, world-wide research is being made for a variety of services to provide QoS. he goal of DiffServ is to offer scalable differentiated service in Internet which are made possible by traffic classification and conditioning only performed at an edge(or a boundary) node. In case DiffServ was deployed in the Medical multimedia network, it is difficult to estimate how the QoS mechanism would affect totally the network performance. Therefore, we need to verify by simulation the design of algorithm which provide a variety of differentiated services. In QoS for Medical multimedia network, a simulator is designed and implemented using OPNET to investigate the performance of DiffServ QoS support mechanism. The developed DiffServ simulator may generate packets according to random, and bursty traffic models in order to incorporate diverse traffic conditions in the Medical multimedia network environment. Based on our simulation results, we confirmed that service differentiation is possible by using the EF(Expedited Forwarding) class in DiffServ networks.

• Journal of Environmental Impact Assessment
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• v.10 no.2
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• pp.85-98
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• 2001

This study was conducted to investigate the geochemical factors governing the distribution of heavy metals(Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in the marine surface sediment samples collected from the Samcheonpo coal-fired power plant. Variations of absolute metal concentrations were related to those in textural and/or carbonate and organic matter content. Most elements, except for Pb, showed generally lower contents compared with the average shale concentration, and the effect of anthropogenic input appeared to be minimal in the sediments. Computations of LF%(labile fraction) and EF(enrichment factor) based on all trace metal data indicated the presence of mineralogical control for Co, Cr, Cu, Ni, and Zn, and anthropogenic contamination for Pb, which needs to be considered in the design of long term monitoring programmes.

• Bulletin of the Korean Chemical Society
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• v.22 no.12
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• pp.1361-1365
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• 2001

Recombinant immunotoxins are hybrid cytotoxic proteins designed to selectively kill cancer cells. A divalent immunotoxins, [B3(FabH1)-PE38]2, was constructed by recombining Fab domain of B3 antibody as a cell-targeting domain and Pseudo monas exotoxin A (PE) as a cytotoxic domain. Monoclonal antibody, B3, is the murine antibody (IgG1k) directed against Lewis Y-related carbohydrate antigens, which are abundant on the surface of many carcinomas. Fab fragment of this antibody was used in this study with the modified hinge sequence where last two cysteines out of three were mutated to serine. PE is a 66 kDa bacterial toxin that kills eukaryotic cells by inhibiting protein synthesis with ADP ribosylation of ribosomal elongation factor 2 (EF2). Fc region of B3 antibody was substituted with the truncated form of PE (38 kDa, PE38) on DNA level. [B3(FabH1)-PE38]2 was formed by disulfide bond between cysteines in the modified hinge region of B3(FabH1)-PE38. Each polypeptide for recombinant immunotoxins was overexpressed in Escherichia coli and collected as inclusion bodies. Each inclusion body was solubilized and refolded, and cytotoxic effects were measured. Divalent immunotoxins, [B3(FabH1)-PE38]2, had ID50 values of about 10 ng/mL on A431 cell lines and about 4 ng/mL on CRL1739 cell lines. Control immunotoxins, B3(scFv)-PE40, had ID50 values of about 28 ng/mL on A431 cell lines and about 41 ng/mL on CRL1739 cell lines. Divalent immunotoxins, [B3(FabH1)-PE38]2, had higher cytotoxic effects than B3(scFv)-PE40 control immunotoxins.

• IMMUNE NETWORK
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• v.3 no.1
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• pp.16-22
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• 2003

Background: The S100A2 gene, also known as S100L or CaN19, encodes a protein comprised of 99-amino acids, is a member of the calcium-binding proteins of EF-hand family. According to a recent study, this gene was over-expressed in several early and malignant carcinomas compared to normal tissues. To elucidate the role of S100A2 protein in the process during carcinogenesis, production of monoclonal antibody specific to the protein is essential. Methods: First, cDNA sequence coding for ORF region of human S100A2 gene was amplified and cloned into an expression vector to produce GST fusion protein. Recombinant S100A2 protein and subsequently, monoclonal antibody to the protein were produced. The specificity of anti-S100A2 monoclonal antibody was confirmed by immunoblot analysis of cross reactivity to other recombinant proteins of S100A family (GST-S100A1, GST-S100A4 and GST-S100A6). To confirm the relation of S100A2 to cervical carcinogenesis, S100A2 protein in early cervical carcinoma tissue was immunostained using the monoclonal antibody. Results: GST-S100A2 recombinant protein was purified by affinity chromatography and then fusion protein was cleaved and S100A2 protein was isolated. The monoclonal antibody (KK0723; Korean patent pending #2001-30294) to the protein was produced and the antibody did not react with other members of EF-hand family proteins such as S100A1, S100A4 and S100A6. Conclusion: These data suggest that anti-S100A2 monoclonal antibody produced in this study can be very useful for the early detection of cervical carcinoma and elucidation of mechanism during the early cervical carcinogenesis.

• The Journal of Internal Korean Medicine
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• v.22 no.2
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• pp.161-174
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• 2001

Objectives : The purpose of this investigation is to evaluate the effect of Chungpesagan-Tang Extracts on reversible forebrain ischemia in Sprague-Dawley rats. Methods : the volume of cerebral infarction and edema, the pathohistological change of neurons, the number of survived neurons, neurotransmitters through immunohistochemical methods, proteins connected with neurotransmitters through immunohistochemical methods and the pathohistological change of neurons through electro-microscopy were investigated. From these reseach data, the protection of neurons and the activity of brain cells were examined. Results : 1. The infaction volume of the control group was 23.9%, and that of the sample group was 16%. 2. The brain edema volume of the control group increased by 17% compared to the normal group and that of the sample group increased by 10%. 3. The light microscopy revealed that the neurons in the ischemia-induced area and CA1 area of hippocampus were most heavily damaged and that the sample group was less damaged compared with the control group. Most pyramidal neurons died in 7 days when brain ischemia was induced. 4. The number of survived pyramidal neurons in the CA1 area of the hippocampus were studied. The normal group had 93 neurons/mm, survived the control group(after 3 days) had 21/mm, the control group(after 7 days) had 3/mm and the sample group 33/mm. 5. The immunohistochemical methods revealed that: (1) In the control group, the sensitivity of GABA, NOS, DBH were increased, and those of Synapsin, eEF-$1{\alpha}$ decreased. NOS and DBH had positive reactions in the control group, but negative in the normal group. (2) In thd sample group, the sensitivity of GABA, NOS, DBH were attenuated, and those of NPY, Synapsin, CaMKII, eEF-$1{\alpha}$ increased when compared to the control group. 6. The electro-microscopy revealed that most neurons died by necrosis and some neurons died by apoptosis. Several imflammation cells appeared in the injured area of neurons. The number of neurons in the sample group that died by ischemia decreased. But, the number that died by apoptosis did not significantly change. Conclusions : The data shows that the effect of Chungpesagan-Tang Extracts on reversible forebrain ischemia in Sprague-Dawley rats is significant.

• The Journal of Internal Korean Medicine
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• v.22 no.2
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• pp.135-144
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• 2001

Objectives : The purpose of this investigation is to evaluate the effects of Woohwangcheongsim-won on neuronal death of hypoxic E18 cortical neuroblast. Methods : To evaluate the effect of Woohwangcheongsim-won on neuronal death caused by hypoxia, the survival rate of E18 cortical neuroblast was measured with MTT assay and the changes of several synaptic proteins and enzymes were investigated with the immunoblot assays. Results : The E18 cortical neuroblasts were added 50, 100, 500, 1,000, and $5,000{\mu}g/ml$ Woohwangcheongsim-won. They showed neurotoxicity, when the concentration of Woohwangcheongsim-won was above $1,000{\mu}g/ml$. The E18 cortical neuroblasts, which were added 50, 100, and $500{\mu}g/ml$ Woohwangcheongsim-won, were exposed 98% $N_2/5%\;CO_2$ for 3 hours to induce hypoxia, 3 days later, the survival rate of $50{\mu}g/ml$ Woohwangcheongsim-won was 141.5% when compared to the control group. On the immuneblot assays, the expressions of ${\alpha}$CaMKII, NR2A, NR28, PDE2, PSD-95, and eEF-$1{\alpha}$ were increased in normoxia, but those of NR2A, NR2B were decreased in hypoxia when compared to the control group. Conclusions : The data shows that the effects of Woohwangcheongsim-won on neuronal death of hypoxic E18 cortical neuroblast is a significant result.