• Bulletin of the Korean Chemical Society
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• v.34 no.3
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• pp.837-850
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• 2013

Bovine viral diarrhea virus (BVDV), a major pathogen of cattle, is a well-characterized pestivirus which has been used as a good model virus for HCV. The RNA-dependent RNA polymerase (RdRp) plays a key role in the RNA replication process, thus it has been targeted for antivirus drugs. We employed two-dimensional quantitative structure-activity relationship (2D-QSAR) and molecular field analysis (MFA) to identify the molecular substructure requirements, and the particular characteristics resulted in increased inhibitory activity for the known series of compounds to act as effective BVDV inhibitors. The 2D-QSAR study provided the rationale concept for changes in the structure to have more potent analogs focused on the class of arylazoenamines, benzimidazoles, and acridine derivatives with an optimal subset of descriptors, which have significantly contributed to overall anti-BVDV activity. MFA represented the molecular patterns responsible for the actions of antiviral compound at their receptors. We conclude that the polarity and the polarizability of a molecule play a main role in the inhibitory activity of BVDV inhibitors in the QSAR modeling.

• Proceedings of the Korean Society for Bioinformatics Conference
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• 2004.11a
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• pp.210-218
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• 2004

Poly(ADP-ribose)polymerase-1 (PARP-1) is a nuclear enzyme involved in various physical functions related to genomic repair, and PARP inhibitors have therapeutic application in a variety of neurological diseases. Docking and the QSAR (quantitative structure-activity relationships) studies for 52 PARP-1 inhibitors were conducted using FlexX algorithm, comparative molecular field analysis (CoMFA), and hologram quantitative structure-activity relationship analysis (HQSAR). The resultant FlexX model showed a reasonable correlation (r$^{2}$ = 0.701) between predicted activity and observed activity. Partial least squares analysis produced statistically significant models with q$^{2}$ values of 0.795 (SDEP=0.690, r$^{2}$=0.940, s=0.367) and 0.796 (SDEP=0.678, r$^{2}$ = 0.919, s=0.427) for CoMFA and HQSAR, respectively. The models for the entire inhibitor set were validated by prediction test and scrambling in both QSAR methods. In this work, combination of docking, CoMFA with 3D descriptors and HQSAR based on molecular fragments provided an improved understanding in the interaction between the inhibitors and the PARP. This can be utilized for virtual screening to design novel PARP-1 inhibitors.

• Journal of Environmental Health Sciences
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• v.45 no.5
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• pp.457-464
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• 2019

Objectives: Quantitative structure-activity relationship (QSAR) is one of the effective alternatives to animal testing, but its credibility in terms of toxicity prediction has been questionable. Thus, this work aims to evaluate its predictive capacity and find ways of improving its credibility. Methods: Using $TOPKAT^{(R)}$, OECD toolbox, and $Derek^{(R)}$, all of which have been applied world-wide in the research, industrial, and regulatory fields, an analysis of prediction credibility markers including accuracy (A), sensitivity (S), specificity (SP), false negative (FN), and false positive (FP) was conducted. Results: The multi-application of QSARs elevated the precision credibility relative to individual applications of QSARs. Moreover, we found that the type of chemical structure affects the credibility of markers significantly. Conclusions: The credibility of individual QSAR is insufficient for both the prediction of chemical toxicity and regulation of hazardous chemicals. Thus, to increase the credibility, multi-QSAR application, and compensation of the prediction deviation by chemical structure are required.

• Journal of Korea Trade
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• v.23 no.5
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• pp.45-65
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• 2019

Purpose - As the well-known Structure-Conduct-Performance paradigm implies, risk structure of a corporation may affect its risk management activity and the activity may in turn determine its performance. Depending on its goal, Foreign Direct Investment (FDI) can shape its risk structure, risk management and its performance. Under this assumption, we investigate the relationship between the goals of FDI and risk management for the first time in academics. Design/methodology - This empirical research uses a survey of 279 current Korean enterprises' FDIs in China with the recently developed business risk quadrant model. Companies are classified into either a market- or an efficiency-seeking group, to identify how each group perceives and manages risks, and values the performance of risk management. Also, we apply integrated risk management method that multinational corporations have introduced in China, then verify the mediating effect between risk factors and performance. Findings - Our research shows the FDIs can expose themselves to differing risk structure although risk management activities simply represent the level of empowerment given to local management by headquarter due to limit of sample size despite diversity of risk and risk management tools. To sum, market seekers are found to have more strategic risk (revenue related risk) than efficiency seekers with financial risk (cost related risk). The market seekers can manage their risk by empowering their local organisation while the efficiency does the opposite ways. The risk management appears to be successful in general. Originality/value - Previous studies on small and medium enterprises' FDIs to China have concentrated on the analysis of entry determinants, withdrawal factors and individual risk management. Meanwhile, this research establishes enterprise-wide risk factors faced by the companies that advance into China, according to the method of the classification by ERM and verifies if they could synthetically improve performance through risk corresponding measures.

• International Commerce and Information Review
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• v.12 no.4
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• pp.111-126
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• 2010

This paper provides an empirical investigation of the determinants of current accounts utilizing an exchange rate (ER), terms of trade (NET), industrial activity (IPI), world import volume (WIM), trade share of the China and Japan (CHJP), proportion of service trade (SERV). The period examined is 1991:1 through 2010:2. It is tested under different cases such as whether variables were cointegrated and whether there was an equilibrium relationship. The result showed that the hypothesis of no cointegrated vector could be rejected at the 5 percent level. The estimated error correction model showed that adjustment speed is fast. This paper also applies impulse-response functions to get additional information by considering the responses of the current account to the shocks of economic variables. The results indicate that current account responds negatively to industrial activity and proportion of service trade, and then decays very quickly.

• Management & Information Systems Review
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• v.33 no.4
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• pp.63-75
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• 2014

The paper investigates empirically the determinants of standardization activity at the industry level, focusing on market structure. The enactments or amendments of collective standards is used as the proxy variable for standardization activity. The independent variables, in addition to market structure, are technological opportunity, factor intensity, export ratio, and industry characteristics(assembly). We estimated the logistic regression model(so-called Logit), using the pooling data for 9 Korean industries, including foods, textiles, chemicals, nonmetallic minerals, metals, electronics and electrics, machinery, automobiles, and shipbuilding, over 2006-2009. The empirical finding shows that market structure has no any effects on the enactments or amendments of collective standards in Korea. This might infer that oligopolistic firms devote themselves to de facto standards determined by market rather than de jure standards such as collective standards and Korean Standards(KS). Besides market structure variable, whereas technological opportunity and assembly characteristics are likely to relate positively with the enactments or amendments of collective standards, capital intensity and export ratio have no any relationship with industrial standardization, respectively.

• Journal of the Korean Magnetic Resonance Society
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• v.19 no.2
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• pp.54-60
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• 2015

Papiliocin, from the swallowtail butterfly, Papilio xuthus, shows high bacterial cell selectivity against Gram-negative bacteria. Recently, we designed a 22mer analog with N-terminal helix from $Lys^3$ to $Ala^{22}$, PapN. It shows outstanding antimicrobial activity against Gram-negative bacteria with low toxicity against mammalian cells. In this study, we determined the 3-D structure of PapN in 300 mM DPC micelle using NMR spectroscopy and investigated the interactions between PapN and DPC micelles. The results showed that PapN has an amphipathic ${\alpha}$-helical structure from $Lys^3$ to $Lys^{21}$. STD-NMR and DOSY experiment showed that this helix is important in binding to the bacterial cell membrane. Furthermore, we tested antibacterial activities of PapN in the presence of salt for therapeutic application. PapN was calcium- and magnesium-resistant in a physiological condition, especially against Gram-negative bacteria, implying that it can be a potent candidate as peptide antibiotics.

• Knowledge Management Research
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• v.13 no.4
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• pp.31-54
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• 2012

This study examines whether employees' legitimacy perceptions of corporate social responsibility (CSR) affect their organizational citizenship behavior (OCB). It also investigates whether CEO's visionary leadership can moderate this causal relationship. CSR legitimacy is defined in the current study as employees' personal beliefs about the appropriateness of corporate CSR activities. In fact, employees evaluate the appropriateness of CSR activity based on its consistency with corporate philosophy (e.g. corporate mission, vision, and values) which functions as employees' referencial belief structure. If CSR activity is perceived as one of firm's effort to fulfill its mission, vision, and values, which means that espoused theory and theory-in-use of CSR activity are congruent, employees will consider firm's CSR activity as legitimate. If, however, employees think that CSR activity is not congruent with firm's mission, vision, and values, which means that espoused theory and theory-in-use of CSR activity are inconsistent, they will perceive that CSR activity of their firm is not legitimate. In the current study, we propose that employees who perceive that the CSR activity of their firm is legitimate are more likely to engage in OCB. In addition, we hypothesize that CEO's visionary leadership can strengthen the positive effect of employees' perception of CSR legitimacy on their OCB. We tested these hypotheses with the sample of 383 employees from 32 companies listed on DJSI (Dow Jones Sustainability Index) Korea 2009. We employed the HLM (hierarchical linear modeling) program to decompose the multi-level random effects. We found that CSR legitimacy perceptions of employees increase employees' OCB and that CEO's visionary leadership moderates this relationship. We discussed implications of these findings in more detail.

• YAKHAK HOEJI
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• v.48 no.4
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• pp.254-260
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• 2004

Structure-activity relationship studies of allylamine type of antimycotics were carried out to evaluate the effect of naphthyl and methyl portion of naftifine. Compounds with 2,4-difluorophenyl( 2a-5a), 2,5-difluorophenyl(2b-5b), 4-ethylphenyl(2c-5c), 2-hydroxyphenyl(2d-5d) and 2-methylnaphthyl(2e-5e) instead of naphthyl group with hydrogen(3a-3e), methyl(4a-4e), and ethyl(5a-5e) in the place of methyl in naftifine were synthesized and tested their in vitro anti-fungal activity against five different fungi. Eight compounds( 3a, 4a, 5a, 3d, 4d, 4d, 5d, 3e, and 4e) showed significant anti-fungal activity against T. mentagroPhytes. (E)-N-(3-Phenyl-2-propenyl)-2- hydroxy-benzenemethaneamine( 3d) displayed moderate antifungal activity against all five different fungi.

• Journal of Ginseng Research
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• v.14 no.3
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• pp.373-378
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• 1990

Free malonaldehyde was determined in nine kinds of ginseng polyacetylene-treated micro- some by HPLC analysis. Antioxidant activities of some phenolic compounds and ginseng saponin were also drtermined both by a new HVLC method and by THA method. A new HPLC system separaterl malonaldehyde at a retention time 5,6 min and showed a linear relationship between the peak are a and malonaldehyde concentration. Panaxnol showed the strongest activity among nine polyacetylenes and the addition of either chlorine or aletyl group reduced polyacetylene's own activity. Since C14-polyacetylenes such as panaxyne and panaxyne-epoxide had little or no antioxidant activities, S17-structure should be preserved to exert a radical-scvenging or trapping activity. The antioxidant activities of chlorogenic acid, ferulic acid and catechol were much weaker than those of C17-polyacetylenes. Ginseng saponin showed no antioxidant activity. Since TBA reactive substances and malonaldehyde contents were almost the same in peroxiedized microsome. TBA value seems a good indicator for lipid peroxidation in this particular Fe+3 ADP/NADPH system.