• KSBB Journal
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• v.29 no.1
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• pp.58-66
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• 2014

Demand for in vitro pharmacological evaluation and toxicity test using human hepatocytes has been increasing. In USA and Europe, human hepatocytes obtained from donated whole liver unsuitable for transplantation were distributed to researchers and deposited in cell bank facility as cryopreserved vial. In Korea, however, incidence of transplantation- inappropriate whole liver has been quite low and the whole livers almost have so severe liver disease such as fatty or fibrotic liver that cannot meet the demand. In this study we aimed to isolate human hepatocytes from liver resection surgery-originated partial liver, and assure the isolated human hepatocytes and its cryopreserved hepatocytes to be qualified for the in vitro pharmacological evaluation and drug toxicity tests. We compared those with commercially available human hepatocyte, BD $GenTest^{TM}$ by cell morphology, hepatic gene expression, urea synthesis, albumin secretion, ammonia removal, and cytochrome P450 induction activities. Changes in hepatotoxic gene expression after cryopreservation are evaluated with a typical hepatotoxic drug, acetaminophen. Consequently, the fresh hepatocytes from the partial liver and its cryopreserved hepatocytes expressed their intrinsic hepatic functions well and showed equal hepatotoxicity gene expression trend regardless to cryopreservation. Therefore, liver resection surgery-originated partial liver can be used as a useful source of human hepatocytes for various pharmacological and hepatotoxicity test.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.4
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• pp.410-415
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• 2008

This study was performed to observe the antimutagenic and cytotoxic activities of methanol extract of kochujang added with sea tangle and deep sea water salts (SDK) and kochujang added with sea tangle (SK) using the Ames test and SRB assay, respectively. The direct antimutagenic effect of SDK and SK methanol extracts were examined by Ames test using Salmonella Typhimurium TA98 and TA100. In the Ames test, methanol extract of SDK and SK alone did not exhibit mutagenicity and most of the samples showed high antimutagenic effects against mutation induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and 4-nitroquinoline-1-oxide (4NQO). Methanol extract of SDK ($200{\mu}g$/plate) showed approximately 71.4% inhibitory effect on the mutagenesis induced by 4NQO against TA98 strain; whereas 56.1% and 83.6% inhibitions were observed on the mutagenensis induced by 4NQO and MNNG against TA100 strain. The cytotoxic effects of SDK and SK increased with increasing sample concentration against human cervical adenocarcinoma (HeLa), human hepatocellular carcinoma (Hep3B), human breast adenocarcinoma (MCF-7), human stomach adenocarcinoma (AGS), and human lung carcinoma (A549). The SDK at the concentration of 1 mg/ml showed cytotoxicities of 61.5%, 61.3%, 51.4%, 57.9% and 77.7% against HeLa, Hep3B, MCF-7, AGS and A549, respectively. In contrast 1 mg/ml treatment of SDK and SK methanol extract had only $2{\sim}38%$ cytotoxicity on human transformed primary embryonal kidney cell (293).

• Journal of Dental Rehabilitation and Applied Science
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• v.26 no.3
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• pp.241-251
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• 2010

This study aims at contributing to the restorative dentistry by examining results in the vertical load test of four different low invasive fixed partial dentures. Based on a hypothesis on the right upper first molar is missing, three units of FPDs were made for the second premolar and the second molar abutment. that is, twelve metal dies and FPDs were made for resin bonded FPD and Two Key Bridges and Human Bridge without occlusal rest and Human Bridge with occlusal rest. By using universal test machine, the numerical maximum value were recorded during the vertical load test of each FPDs after the bonding process treated by Maxcem which is resin cement. The failure process and its result of prosthesis were also observed. The maximum load was 7,295 N, 4,729 N, 2,190 N, 3,073 N from groups of resin bonded FPD, Two Key Bridge, Human Bridge without occlusal rest and Human Bridge with occlusal rest respectively. There was a statistical significance among the groups of resin bonded FPD, Two Key Bridge and Human Brides. However, there was no significant difference between Human Bridge without occlusal rest and Human Bridge with occlusal rest. Regarding the failure of prosthesis, the groups of Resin Bonded FPD and Two Key Bridge showed that one of the abutment teeth in the both side of retention part was highly failed earlier than the other one (83.2% and 66.6% respectively). While, Human Bridge without occlusal rest and Human Bridge with occlusal rest showed high percentage of failure in the abutment teeth in the both side of retention part at the same time (91.6% and 58.3% respectively). This study demonstrates that the group of Human Bridges has low resistance to the vertical loads of low invasive FPDs in comparison with the groups of resin bonded FPD and Two Key Bridge. Nevertheless, the maximum occlusal load of the restorative position, resistance to diverse restoration failure, amount of tooth reduction and patients' cooperation should be considered when they are applied in the clinic in order to choose an appropriate restoration for each patient.

• Journal of Periodontal and Implant Science
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• v.29 no.4
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• pp.821-838
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• 1999

On the basis of the evidences that electrical stimulation could enhance proliferation and differentiation of bone cells and promote healing and regeneration of bone, this study was performed to investigate the effects of electrical stimulation on human periodontal ligament cells and gingival fibroblasts in vitro, which also have important roles in regeneration of periodontium, and to evaluate the potential of clinical application of electrical stimulation. Human periodontal ligament cells and gingival fibroblasts were primarily cultured from the root surface of extracted premolar and the adjacent gingiva without periodontal diseases. In control group, the cells ($5{\times}10^4$ cells/ml)were incubated only in Dulbecco's Modified Eagle's Medium contained with 10% fetal bovine serum. In test groups, electrical stimulation was given at the current intensity of $0.25{\mu]A$(test group 1), $1.0{\mu}A$(test group 2), and $2.5{\mu}A$(test group 3) for 12 hours to the same culture media with the control group. After 12 hour exposure of electrical stimulation, the cells were incubated for 2 and a half days(60 hours), and then each group of cells was analyzed for cell proliferation, protein level, and activity of alkaline phosphatase. The results were as follows ; 1. The Rate of cell proliferation of every test group increased significantly in both periodontal ligament cells and gingival fibroblasts, and in periodontal ligament cells, test group 3 showed significantly increased proliferation compared to the other test groups(p<0.05). 2. In the protein levels, neither periodontal ligament cell nor gingival fibroblast showed statistically significant differences between control and test groups. 3. The activity of alkaline phosphatase in periodontal ligament cells increased significantly in all test groups(p<0.05), but there were no significant differences between 3 test groups. In gingival fibroblasts, the activity of alkaline phosphatase increased significantly only in test group 3(p<0.05). From the above results, it is concluded that electrical stimulation may have beneficial effects on the regeneration of destructed periodontal tissue in regard of the stimulation of periodontal ligament cells and gingival fibroblasts as well as electrically stimulated bone formation that has been known, and that electrical stimulation may have the potential of clinical application.

• Archives of Pharmacal Research
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• v.21 no.3
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• pp.305-309
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• 1998

Human cytochrome P450 1A2 is one of the major cytochrome P450s in human liver. It is known to be capable of activating a number of carcinogens such as arylamines and heterocyclic amines. In order to develop the new bacterial mutagenicity test system with human P450, a full length of human P450 1A2 cDNA inserted into pCW bacterial expression vector was introduced to Escherichia coli WP2 uvrA strain which is a well-known E. coli strain for bacterial reverse mutagenicity assay. Expressed human P450 1A2 showed typical P450 hemoprotein spectra. Maximum expression was achieved at 48 hrs after incubating at $30^{\circ}C$ in terrific broth containing ampicillin, IPTG and other supplements. High level expression of P450 1A2 in E. coli WP2 uvrA membranes was determined in SDS-PAGE. The well-known mutagens 2-aminoanthracene and MElQ increased the revertant colonies of E. coli WP2 uvrA expressing human P450 1A2 without an exogenous rat hepatic post-mitochondrial supernatant (S9 fraction) in a dose-dependent manner. The results show that the functional expression of human P450 in bacterial mutagenicity tester strain will provide a useful tool for studying the mechanism of the mutagenesis and carcinogenesis of new drugs and environmental chemicals.

• Journal of Sport and Applied Science
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• v.5 no.2
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• pp.31-38
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• 2021

Purpose: A new form of sports human rights platform is needed for policy-related officials, athletes, leaders, and parents to easily share information on sports human rights and to promote communication between the sports community and the outside. Research design, data, and methodology: Participants were collected from athletes (n=3,007) who were registered in Korean Sport & Olympic Committee. Participants were asked to respond the survey items measuring their experiences of human right violations in sport. Descriptive analysis, t-test, and ANOVA were used to analyze data. Results: The platform should include information on prevention and safety of human rights violations during sports activities, procedures and methods for reporting damage, countermeasures, leader education programs, human rights protection guidelines, roles and supervision of sports organizations and institutions, and related statues. It can form a community as well as exchange information in the Internet space through the operation of bulletin boards by professional athletes, student athletes, parents, and leaders, and plays a role in crisis counseling or information provision. Given the reality that players can be blocked from the outside world, information communication channels on SNS can be a useful means of protecting and improving players' human rights. Conclusions: Therefore, it is necessary to provide a foundation for creating related platforms so that sports human rights sites or SNS can be operated voluntarily. Implications and future directions were discussed.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.6
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• pp.447-453
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• 2021

Human resources play a key role in developing and enhancing the manner in which an organization change. In fact, the role of human resource-related quality management has contributed greatly to the growth of the organization in both the short and long term. The purpose of the current study is to identify factors that influence human resource retention in Hanoi in the backdrop of growing economic performance of Hanoi in Vietnam's economy. Primary data was collected through questionnaires of 280 respondents from the four districts in Hanoi, including 25.2% of respondents working in Cau Giay district, 21.2% in Dong Da district, 34.2% in Ha Dong district, and 19.4% in Thanh Xuan district. After applying Cronbach's Alpha and Explore Factor Analysis (EFA) analysis, Durbin-Watson test, empirical results demonstrate that relationship among co-workers has a significant and positive contribution on the maintenance of human resources in the organization. Additionally, higher welfare facilities for an employee are more likely to impact the maintenance of human resources in the organization. Factors such as working environment, job placement, and leadership relationship have no adverse effect on the maintenance of human resources, although a positive impact could be established in all cases.

• Korea Journal of Hospital Management
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• v.9 no.1
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• pp.95-114
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• 2004

The purpose of this study was to identify the relationship between organizational culture based on the competing values approach, human resource management practices and organizational performance at a hospital. Participants were 138 employee in a general hospital. Data were collected during May, 2003 using four structured instruments. The data were analyzed using Chi-square test, One-way ANOVA, $scheff{\acute{e}}$ test and Cluster analysis. Three clusters were derived from cluster analysis. The first cluster consisted of cultures which were mixed developmental, consensual, hierarchial and rational culture equivalently. The second cluster consisted of the weak cultures, which was lower score than other clusters. The third cluster consisted of strong comprehensive cultures, which had higher score than other clusters. In the three clusters, hierarchial and rational culture were superior. The difference between human resource management practices and organizational commitment in organizational performance according to organizational culture clusters was found to be statistically significant. The cluster which had strong comprehensive cultures, in contrast to other clusters, more significantly affects on human resource management practices and organizational commitment. However, the strength of organizational culture does not have a significant effect on customer oriented service performance in organizational performance. These results showed that types of organizational culture were significantly related to human resource management practices and organizational commitment, and understanding the existing culture is essential to develop the organization of hospitals.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.5
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• pp.836-842
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• 2016

When an accident occurs in the nuclear power plant, the faulted information might mislead to the high possibility of aggravating the accident. At the Fukushima accident, the operators misunderstood that there was no core exposure despite in the processing of core damage, because the instrument information of the reactor water level was provided to the operators optimistically other than the actual situation. Thus, this misunderstanding actually caused to much confusions on the rapid countermeasure on the accident, and then resulted in multiplying the accident propagation. It is necessary to be equipped with the function that informs operators the status of instrument integrity in real time. If plant operators verify that the instruments are working properly during accident conditions, they are able to make a decision more safely. In this study, we have performed various tests for the fault detection sensitivity of an data-driven empirical model to review the usability of the model in the accident conditions. The test was performed by using simulation data from the compact nuclear simulator that is numerically simulated to PWR type nuclear power plant. As a result of the test, the proposed model has shown good performance for detecting the specified instrument faults during normal plant conditions. Although the instrument fault detection sensitivity during plant accident conditions is lower than that during normal condition, the data-drive empirical model can be detected an instrument fault during early stage of plant accidents.

• Journal of the Korean Society of Safety
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• v.26 no.3
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• pp.15-22
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• 2011

Explosion and fire cause about 30 reported industrial major accidents a year by ignition source which discharge of electrostatic generated to flammable gas, vapor, dust and mixtures. It brings economically and humanly very large loss that accident was caused by fire and explosion from electrostatic discharge. Thus, it is very important that electrostatic discharge energy is to be control below not to be igniting flammable mixtures. There are two kinds of analysis model for electrostatic discharge, human body model and machine model. Human body model is available the parameter of human's electrical equivalent that capacitance is 100 pF, resistance is $1.5k{\Omega}$. To simulate and visualize the electrostatic discharge from human body need a very expensive and high voltage simulator. In this paper, we measured the value of capacitance and resistance concerned with test materials and sizing of specimen and the value of charged voltage concerned with test specimen and distance to develop an electrostatic charge/discharge simulating tool for teaching with which concerned industrial employee and students. The result of experiments, we conformed that the minimum ignition energy of methane-oxygen mixtures meets well the equation $W=1/2CV^2$, and found out that the insulating material and sizing of equivalent value having human body mode are the poly ethylene of 200 mm and 300 mm of diameter. Developed electrostatic charge/discharge simulating tool has many merits; simple mechanism, low cost, no need of electric power and so on.