• Parasites, Hosts and Diseases
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• v.26 no.4
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• pp.229-238
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• 1988

In vitro culture of Toxoplasma gondii in HL-60 cells and cell-mediates immunity against Toxoplasma in dimethylsulfoxide(DMSO) -induced HL-60 cells, i.e., differentiation into granulocytes, were pursued. HL-60 calls were treated with various concentrations of DMSO, and 1.3%(v/v) for 3 day incubation was chosen as the optimal condition icy differentiation into granulocytes. The degree of differentiation was assayed in physiological and functional aspects in addition to morphological point. When treated with 1.3% DMSO for 3 days, HL-60 cells did not synthesiar DNA materials beyond background level, and showed active chemotactic response to chemotactic peptide, formal-methionyl-leucyl-phenylalanine(FMLP). Morphologically promyelocytes of high nuclearlcytoplasmic(NIC) ratio changed to granulocytes of relatively low WJC ratio. The relationships between HL-60 cells or DMSO-induced HL-60 cells and Toxoplasma were examined after stain with Giemsa and Buorescent dye (acridine orange). HL-60 cells did not show any sign of torso- plasmacidal activity but showed intracellular proliferation of Texoplasma to form rosette for 72 hr co-culture. In contrast, OMSO-induced HL-60 cells phagocytosed Toxoplasma within 1 hr, and performed a process of intracellular digestion of Toxoplasma thereafter. With the above results, it is suggested that phagosome-Iysosome fusion is one of the critical events for the parasitism by Toxoplasma or for susceptibility of host cells. The in vitro culture system of this study has offered a defined condition to study the protozoan parasite-host cell interactions.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1059-1068
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• 2011

This study is aimed to systematically grasp the visual and informative needs of sign system and secure the formativeness sample for standardization model. This study, therefore, will help building the requirements to create design value and secure objectiveness for realization of practical use of the communication design plan, and means transference of the external and internal information system of railroad vehicles for practical use into the standardization model. The pictorial sign based information delivery is a communication process and way gained through vision and perception, so that grasping the formative structure connoted in message is not less than understanding the characteristics of the essence. In this study, I defined the symbolic expressions inherent in TTX sign system to be perceptional action and value norms as general signatures and signifiers.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.11 no.4
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• pp.227-236
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• 2016

The competition among insurance companies has become increasingly intense driven by the recent changes in financial environment. In this study, we (i) categorize the quality of life insurance services into the core service, relational services, and additional services, (ii) assess the impact of each service on repurchase intension, and (iii) investigate if customer satisfaction has a mediating effect. The research subjects are 215 life insurance customers who were selected from an online survey respondent population. Based on the analysis we performed by utilizing the SPSS 18.0, we concluded that (i) maintaining service of the core services, internal relationship of service personnel and insurance salesmen of the relational service and additional services have a positive impact on repurchase intention and (ii) In the relationships between repurchase intentions, the customer satisfaction is fully mediated by maintaining service and insurance salesman and partially mediated by additional service. The results of this study can be meaningful for both industry and academia, because these results can be utilized as useful evidence in understanding selection behavior of life insurance customers and deriving various strategies in business environment.

• The Korean Journal of Applied Statistics
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• v.32 no.1
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• pp.1-13
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• 2019

An adaptive seamless Phase II/III clinical trial design enables a reduction in the sample size (in comparison to a conventional design) that also shortens the clinical development time. It is also very effective in clinical trials since it can have higher statistical power than Phase III alone. In this study, we use extensive simulation studies to compare several multiple hypothesis testing methods that can help select the best doses in a Phase II study along with several methods to combine p-values of the Phase II and Phase III study.

• Journal of Science Education
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• v.41 no.3
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• pp.334-350
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• 2017

The purposes of this study are to develop scientific-inquiry based on STEAM education program and to investigate the effects of the program on middle-school students' interests, self-efficacy, and career choice about science, technology/engineering, and mathematics. In order to develop this program, the literature investigation and previous studies were conducted, so that finally the developmental direction was based on scientific inquiry and the developmental theme and model were selected. A total 92 first-graders in G middle-school of Daegu city were participated in this study. A single group pre-post test paired t-test was conducted to figure out changes of students' interest, self-efficacy, and career choices before or after applying this program. In addition, in-depth interviews were conducted with 14 students to find their specific responses. The results of this study were as follows. First, STEAM education program on the theme of 'RC Airplane' was developed on the basis of the 'ADBA' model. Second, the developed STEAM educational program not only results a decisive difference statistically but also has significant effects on middle-school students' interests, self-efficacy, and career choice in science, technology/engineering, and mathematics, who are involved in the free-semester program, across the overall affective domain. In conclusion, the STEAM educational program in this study could affect significant meanings to middle-school students during the free-semester. It could contribute to facilitate middle-school students' education for happiness and to grow the creative STEAM talents.

• Environmental and Resource Economics Review
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• v.17 no.4
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• pp.845-873
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• 2008

This study estimates the VSL(value of a statistical life) as well as the WTP(willingness to pay) for mortality risk reduction using sample selection model with data on liver cancer examination which is associated with little possibility of multi-purpose(i.e. joint production) in averting behavior. The marginal benefits of mortality risk reduction are estimated by applying for household production function model with medical expense and the time required for medical examination of liver cancer. Individuals are more likely to take liver cancer test if they are male, older, higher educated, those with spouse, smoker, more income of household, and more anxious about their health. The costs of liver cancer examination are statistically significantly affected with expected signs by size of mortality risk reduction, sex, period of eduction, those with spouse, and household income. The marginal effect of mortality risk reduction owing to taking liver cancer examination is estimated at 321,097 won. The costs of liver cancer examination are increased by 905 won with more one year of education period and by 1,743 won with more one million won in household income. On liver cancer examination, male spends more 12,310 won than female and those with spouse pay more 7,969 won than those without spouse. Therefore the VSL from mortality risk reduction due to liver cancer examination is 321.10 million won at mean size of mortality risk reduction and mean cost of liver cancer examination. The results of sensitivity tests on costs and effects of liver cancer test shows that the VSLs are estimated in a range from 160.55 million won to 642.19 million won.

• The Korean Journal of Pharmacology
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• v.30 no.1
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• pp.1-9
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• 1994

It has been shown that there are several subtypes of ${\kappa}$ opioid receptor. We examined ligand binding profiles and the effects of various opioid agonists on high potassium-stimulated release of $[^3H]$ histamine. We have evaluated the properties of $non-{\mu},\;non-{\delta},$ binding of $[^3H]\;DIP\;([^3H]\;diprenorphine),$ anonselective opioid antagonist, in rat cortex membranes. Binding $to\;{\mu}\;and\;{\delta}$ sites was inhibited by the use of an excess of competing selective agonists (DAMGO, DPDPE) for these sites. (-) Ethylketocyclazocine (EKC), DIP and bremazocine inhibited $[^3H]$ DIP binding. However, arylacetamides (U69593 and U50488H) gave little inhibition Replacement of sodium by NMDG and the addition of guanine nucleotide influenced the inhibitory potency of (-) EKC, an agonist for {\kappa}_1-and-{\kappa}_2-binding site, but not of bremazocine. This result suggests that bremazocine can be an antagonist at this binding site. Also, we have examined the opioid modulation of $K^+(30mM)-induced\;[^3H]\;histamine$ release in rat frontal cortex slices labeled with $1-[^3H]\;histidine$. The $[^3H]\; histamine$ release from cortex slices was inhibited by EKC in a concentration-dependent manner. However, the ${\delta}$ receptor selective agonists, DPDPE and deltorphine II, ${\mu}$ receptor agonists, DAMGO and TAPS, ${\kappa}_1-agonists$, U69593 and U50488H, and ${\varepsilon}-agonist,\;{\beta}-endorphin,$ did not. The concentration-response curve of EKC was shifted to right in the presence of naloxone, nor-binaltorphimine and bremazocine, respectively. These results suggest that ${\kappa}_2$ opioid receptor regulates histamine release in the fromtal cortex of the rat.

• KDI Journal of Economic Policy
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• v.36 no.4
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• pp.33-69
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• 2014

We investigate determinants of fund investment flows using Korean equity investment funds. Unlike previous studies which analyzed net-flows (inflow minus outflow), we analyze fund investment inflows and outflows separately that should properly reflect investors' fund selection and redemption decision. We find similar effects of past return, fund age on net-flows to existing studies based on US market data. The analysis of determinants of inflows shows that inflows are related to past return, fund age and sales fee as net-flows. In contrast, outflows are found to behave quite differently from inflows. Apparently, asymmetry exists between fund investment inflows and outflows at the Korean fund selection market. Specifically, high past returns increase fund investment inflows while increase, rather than decrease, fund outflows. Moreover, 'convexity' is detected both in inflows and outflows: higher past returns accelerate outflows as well as inflows. Effects of sales fee also differ between inflows and outflows. In the 'affiliated' fund sample, sales fee is negatively related to inflows while positively related to outflows. In the 'unaffiliated' fund sample, sales fee is positively related to inflows, but no significant relationship exists with outflows. Empirical findings of this paper imply that the rational investor's fund selection view cannot provide a consistent explanation of the Korean fund selection market. In particular, the positive and convex relationship between past returns and fund outflows is inconsistent with the rational investor view. The fact that investor's fund investment appears to display 'disposition effect', which has been reported by studies of individual investors' stock investment behaviour suggests that the behavioral finance view should be a part of explanation for the Korean fund selection market. In addition, the strikingly different patterns between the 'affiliated' funds and the 'unaffiliated' funds, imply that brokers' incentive structure is another prevailing factor for fund investment flows.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.8 no.3
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• pp.113-124
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• 2013

The government strives to create venture ecosystem for realizing creative economy, at the same time, the Mistry of Education is spending huge resources and efforts to spread entrepreneurship education to universities in Korea. Since entrepreneurship education gives motivation to individuals and creates market innovation and these connect to the growth of national economy through increased efficiency, entrepreneurship education is becoming increasingly more important for realizing creative economy. Based on the importance, entrepreneurship education in the universities is now spreading rapidly. However, college students' entrepreneurial intention has still not been improved comparing to spreading entrepreneurship education. To overcome the poor improvement, entrepreneurship education needs to be driven more systematic direction through the study on the effect of students' motivation and environment. In this study, entrepreneurship as a part of careers perspectives, is analyzed on students' career reasons with entrepreneurial intention. For this study, 918 surveys was collected from 7 universities having entrepreneurship courses in Seoul and Gyeonggi regions in 2012 and analyzed 858 surveys in order to prove the hypothesis. The results disclosed the relationship between students' career reasons and entrepreneurial self-efficacy and intention. Motivation factors of self-realization, innovation and role model have positive effect on entrepreneurial self-efficacy following by increased entrepreneurial intention, unlike the common notion financial success and independence factors are not significant with entrepreneurial intention of students. Based on these results having meaningful implication to Korea entrepreneurship education, this study is expected to have contribution to the successful promoting the creative economy realization of our government.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.3
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• pp.518-526
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• 2017

This study analyzed the impact of family firms and their characteristics on how they use debts to analyze the decision-making process of Korean family firms. For analysis, we classified the characteristics of family firms into three categories, through the influence of the relationship between the lack of funds and net debt issuance, which was confirmed as the 'packing order theory' of family firms. There was a total of 4,503 enterprises in the Korean Exchange (KRX). The period of analysis was 10 years, between 2004 and 2014. To summarize, Shyam-Sunder and Myers (1999) validated the packing order theory by presenting a model of family businesses that showed greater applicable to higher packing order theory than a model of non-family businesses. Moreover, the results also confirmed the application of the packing order theory by the family stronger corporate governance and ownership structure. The ownership and governance characteristics of the ruling family has also shown the applicability of higher packing order theory.