• Asia pacific journal of information systems
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• v.25 no.4
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• pp.642-661
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• 2015

Interpersonal trust has become essential for online communities because people have managed to be in a situation without face-to-face encounters. To identify the structural relationships between interpersonal trust and learning performance, we analyzed the relationship between two types of trust, namely, cognitive and affective, as well as two dimensions of learning performance, namely, learning satisfaction and knowledge application. We also identified the moderating role of social norms in the relationship between trust and learning performance. Results of analysis are as follows. First, cognitive trust significantly affected the two dimensions of performance. Second, affective trust exhibited a significant effect on learning satisfaction, but did not affect knowledge application. Third, the relationships between the two performance factors were significant and direct. Lastly, social norms appeared to moderate the effects of cognitive trust on knowledge application and affective trust on satisfaction. These findings suggest that organizations, which would like to optimize task-oriented performance of their learning communities, should consider linking strategies between community satisfaction and practical knowledge application.

• Korean Journal of Animal Reproduction
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• v.16 no.4
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• pp.387-397
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• 1993

To examine local response of adenosie(purine nucleoside) on the developing mammary gland, Elvax 40P implants containing adenosine were surgically implanted into mammary fat pad of the five week old female ICR mice. Inguinal(the 4th) mammary glands of anesthetized mice were exposed andplaced the implants for 12 days. One gland was treated with an adenosine implant, while the contralateral gland received a blank implant as control. For whole-mount preparations, glands were stained with alum carmine, and for histological observation, micro-selected mammary glands were stained with hematoxylin and eosin Y. Implantation with Elvax 40P did not affect on the damage of neighboring mammary tissue. Adenosie 25 or 250$\mu\textrm{g}$ per slow-release implant stimulated local mammary end bud formation of ovariectomized mice such as end bud size and numbers of end bud per gland in a dose dependent manner(P<0.05), and lower concentration of adenosie(2.5 or 25$\mu\textrm{g}$/implant) increased numbers of end bud(P<0.05) and end bud size(P<0.1) of intact mice. Adenosine treatment and intact ovarian function had moderate interation effects on the stimulation of end bud formation at 2.5$\mu\textrm{g}$ adenosine/implant(P<0.1). In histological observation, adenosine implants increased numbers of mammary epithelial type of cells at mammary duct in the presence or absece ofovary. These results indicate that adenosine should be one of regulators in mouse mammary ductal growth.

• Biomedical Science Letters
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• v.14 no.4
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• pp.225-231
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• 2008

Non-alcoholic fatty liver disease (NAFLD) is associated with various metabolic abnormalities, including central obesity, type 2 diabetes, dyslipidemia, and high blood pressure. This suggests that NAFLD may represent the hepatic manifestation of the metabolic syndrome. In this study, we investigated unfavorable effects NAFLD on components of metabolic syndrome in post-menopause women. Eight hundred sixty-nine postmenopausal women were recruited for this study. The diagnosis of fatty liver was based on the results of abdominal ultrasonography. Serum levels of fasting glucose, total cholesterol, triglyceride, and HDL-cholesterol were measured. The prevalence of component of metabolic syndrome such as hypertension, hyperglycemia, hypertriglyceridemia, and low-HDL-cholesterol was significantly higher in subjects with NAFLD as compared with those without NAFLD. The moderate to severe grade of NAFLD presented higher levels of serum fasting glucose, fasting insulin, HOMA-IR, total cholesterol, and triglycerides than the mild NAFLD and the normal group. In conclusion, metabolic syndrome risk was increased in post-menopause women with NAFLD as compared with those without NAFLD. The severity of NAFLD affected metabolic syndrome risk factors. The optimal strategy for the treatment of NAFLD is likely to include lifestyle modifications and therapy to improve insulin resistance.

• ALGAE
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• v.26 no.2
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• pp.201-208
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• 2011

A monoterpene lactone, loliolide was successively isolated from brown seaweed, Sargassum ringgoldianum subsp. coreanum using column chromatography and high-performance liquid chromatography. The structure of the isolated compound was determined by comparison of EIMS and NMR spectral data with the previously published data. The antioxidant activities of loliolide were also evaluated by DPPH and $H_2O_2$ radical and intracellular reactive oxygen species scavenging assays, and it showed moderate activities in all antioxidant assays. Furthermore, loliolide was found to exert positive dose-dependent effects in the protective effects against $H_2O_2$-induced cell damage which were determined via MTT, Hoechst staining assays and cell cycle analysis. This is the first study on chemical constituent of this seaweed according to our best knowledge. These results clearly indicated that loliolide isolated from Sargassum ringgoldianum subsp. coreanum can protect the cells against $H_2O_2$-induced cell damage or apoptosis.

• Korean Journal of Pharmacognosy
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• v.35 no.4 s.139
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• pp.338-345
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• 2004

Scavenging effects of DPPH radical and hydroxyl radical, inhibition of linoleic acid oxidation, inhibition of NO synthesis and iNOS expression were tested with extracts and chromatographic subfractions of Canavalia lineata obtained at Jeju island. Chloroform extract and its subfractions gave moderate effects on scavenging DPPH radical and hydroxyl radical, They also inhibited linoleic acid oxidation, and NO synthesis. Inhibition of NO synthesis resulted from the repression of iNOS gene expression. Ethyl acetate extract and its subfractions showed excellent effects on scavenging DPPH radical and hydroxyl radical, while they were cytotoxic.

• Tribology and Lubricants
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• v.26 no.4
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• pp.246-253
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• 2010

Friction characteristics of the brake friction materials without environmentally regulated ingredients were examined to find their role in the brake performance. Five friction materials were produced based on a nearcommercial formulation by changing the relative amount of potentially hazardous ingredients to health and environment, such as $Sb_2S_3$, potassium titanate, and brass fiber. Tribological properties of the friction materials were obtained using a scale dynamometer and Krauss type tribometer. Results showed that the excluded three ingredients played important synergetic effects on tribological properties in terms of fade resistance, wear resistance and friction effectiveness. In particular, brass fibers played important roles in the friction stability by providing excellent thermal diffusivity at the friction interface. Potassium titanate whiskers showed excellent fade resistance and wear resistance compared to the substituted barite. Antimony trisulfide, on the other hand, showed little effect on the high temperature fade resistance and wear resistance, while it increased friction effectiveness at moderate temperatures. The friction materials without the three ingredients showed severe fade, indicating antisynergy effects.

• Journal of Chest Surgery
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• v.15 no.2
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• pp.259-265
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• 1982

We have designed a new type of bubble oxygenator (KOREA-KIM VENOTHERM OXYGENATOR) made of PVC sheet and deforming mesh incorporated in the heat exchanger, and evaluated in experimental animal for the analysis of it`s efficiency. The Oxygenator has low priming volume with high flow rate up to 6 L/rain, and efficiency of heat exchanger was excellent as 1-$1.5^{\circ}C.$ using total cardiopulmonary bypass method under moderate to deep hypothermia. Average priming volume of 1317 ml with 30% hemodilution method was perfused with an average of 1.1-3.0 L/min.$M^2$of arterial blood and pure oxygen at a rate of 2-3.4 L/min for 49.6 minutes continuously in average. During total cardiopulmonary bypass, average $PaO_2$ was $159.8{\pm}60$mmHg, $PaCO_2$ $41.0{\pm}3$mmHg respectively under $SaO_2$ over 96% with systolic arterial pressure of 70 mmHg and CVP of 5-10 cm$H_2O$. Plasma free Hemoglobin was $7.0{\pm}4$ mg/dl with 25% drop of hemoglobin and hematocrit at the end of cardiopulmonary bypass. This KKV Oxygenator was observed to have excellent capabillty of oxygen and carbon dioxide gas transfer with small amount of blood trauma, and the efficiency of heat exchanger was satisfactory during cooling and rewarming of the bubbled blood. Disadvantages have included the somewhat poor deforming effect due to loose PVC fiber mesh, the extracompact character of Teflon filters, and the rough inner surface of the heat exchanger copper pipes.

• The Korean Journal of Rehabilitation Nursing
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• v.11 no.1
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• pp.41-48
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• 2008

Purpose: The study were to identify difference in self-efficacy according to perceived health status in male smokers. Methods: The subjects were 138 male smoker in Seoul and Incheon. The data was collected using structured questionnaires from ninth of July to 16th of August in 2007. The data was analyzed by descriptive statistics and ANOVA with SPSS 14.0. Result: Participants showed that a high level of total self-efficacy score $3.40{\pm}.43$, general self-efficacy score $3.39{\pm}.46$, social self-efficacy score $3.44{\pm}.55$. There were significant difference total self-efficacy and general self-efficacy in accordance with perceived health status. But there were no significant difference social self-efficacy in accordance with perceived health status. With the result of this study, the subjects smoked $14.48{\pm}11.04$ years and 90.4% of the subjects were highly perceived that the health status of oneself above of moderate state and self-efficacy score. Conclusion: Therefore raising a perception about smoking dangerous, the prohibition of smoking program development which emphasizes the noxiousness of smoking for must precede, recognizes the necessity of prohibition of smoking and prohibition of smoking decision in one smoker comes to seem with the fact that own effect increase program for a prohibition of smoking maintenance.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.47-52
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• 2001

Short reinforced concrete bridge piers are particularly susceptible to shear failure as a consequence of the high shear/moment ratio and conservatism in the flexural strength design of existing RC bridge pier, which were constructed before 1992. In addition, shear failure is brittle and involves rapid strength degradation. Inelastic shear deformation is thus unsuitable fur ductile seismic response. It is, however, believed that there are not many experimental research works fur shear failure of the existing RC bridge pier in Korean peninsula subjected to earthquake motions. The object of this research is to evaluate the seismic performance of existing circular RC bridge piers by the quasi-static test. Existing RC bridge piers were moderate seismically designed in accordance with the conventional provisions of Korea Highway Design Specification. This study has been performed to verify the effect of aspect ratio (column height-diameter ratio). Quasi-static test has been done to investigate the physical seismic performance of RC bridge piers, such as lateral force-displacement hysteric curve, envelope curve etc.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.941-946
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• 2002

Short reinforced concrete bridge piers are particularly susceptible to shear failure as a consequence of the high shear/moment ratio and conservatism in the flexural strength design of existing RC bridge pier, which were constructed before 1992. In addition, shear failure is brittle and involves rapid strength degradation. Inelastic shear deformation is thus unsuitable for ductile seismic response. It is, however, believed that there are not many experimental research works for shear failure of the existing RC bridge pier in Korean peninsula subjected to earthquake motions. The object of this research is to evaluate the seismic performance of existing circular RC bridge piers by the quasi-static test. Existing RC bridge piers were moderate seismically designed in accordance with the conventional provisions of Korea Highway Design Specification. This study has been performed to verify the effect of aspect ratio (column height-diameter ratio). Quasi-static test has been done to investigate the physical seismic performance of RC bridge piers, such as lateral force-displacement hysteric curve, envelope curve etc.