• Interaction and multiscale mechanics
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• v.1 no.4
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• pp.423-435
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• 2008

This paper employs the reproducing kernel (RK) approximation for evaluation of field theory-based incompatibility tensor in a polycrystalline plasticity simulation. The modulation patterns, which is interpreted as mimicking geometrical-type dislocation substructures, are obtained based on the proposed method. Comparisons are made using FEM and RK based approximation methods among different support sizes and other evaluation conditions of the strain gradients. It is demonstrated that the evolution of the modulation patterns needs to be accurately calculated at each time step to yield a correct physical interpretation. The effect of the higher order strain derivative processing zone on the predicted modulation patterns is also discussed.

• Journal of Microbiology and Biotechnology
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• v.12 no.5
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• pp.829-833
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• 2002

Angiogenesis is an essential event in a variety of physiological and pathological processes. Therefore, effective inhibition of this event is a promising strategy for treating angiogenesis-related diseases, including cancer. The current study investigated two unique bafilomycin-type macrolide inhibitors of angiogenesls, PC-766B' (1) and PC-766B (2). The strain RK97-56 which produced the inhibitors was identified as Nocardia sp. by chemotaxonomic analyses, and the purification of the inhibitors was guided by their anti-angiogenic activities. PC-766B' (1) and PC-766B (2) exhibited potent inhibitory activities towards endothelial cell migration stimulated by the vascular endothelial growth factor (VEGF).

• Journal of Ginseng Research
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• v.38 no.3
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• pp.180-186
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• 2014

Background: This study evaluated changes in ginsenoside compositions and antioxidant activities in hydroponic-cultured ginseng roots (HGR) and leaves (HGL) with heating temperature. Methods: Heat treatment was performed at temperatures of $90^{\circ}C$, $110^{\circ}C$, $130^{\circ}C$, and $150^{\circ}C$ for 2 hours Results: The ginsenoside content varied significantly with heating temperature. The levels of ginsenosides Rg1 and Re in HGR decreased with increasing heating temperature. Ginsenosides F2, F4, Rk3, Rh4, Rg3 (S form), Rg3 (R form), Rk1, and Rg5, which were absent in the raw ginseng, were formed after heat treatment. The levels of ginsenosides Rg1, Re, Rf, and Rb1 in HGL decreased with increasing heating temperature. Conversely, ginsenosides Rk3, Rh4, Rg3 (R form), Rk1, and Rg5 increased with increasing heating temperature. In addition, ginsenoside contents of heated HGL were slightly higher than those of HGR. The highest extraction yield was 14.39% at $130^{\circ}C$, whereas the lowest value was 10.30% at $150^{\circ}C$ After heating, polyphenol contents of HGR and HGL increased from 0.43 mg gallic acid equivalent/g (mg GAE eq/g) and 0.74 mg GAE eq/g to 6.16 mg GAE eq/g and 2.86 mg GAE eq/g, respectively. Conclusion: Antioxidant activities of HGR and HGL, measured by 1,1-diphenyl-2-picrylhydrazyl and 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid radical scavenging ability, increased with increasing heating temperature. These results may aid in improving the biological activity and quality of ginseng subjected to heat treatments.

• Journal of Ginseng Research
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• v.38 no.2
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• pp.154-159
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• 2014

Background: This study was carried out to investigate the effect of the steaming process on chemical constituents, free radical scavenging activity, and antiproliferative effect of Vietnamese ginseng. Methods: Samples of powdered Vietnamese ginseng were steamed at $120^{\circ}C$ for various times and thei extracts were subjected to chemical and biological studies. Results: Upon steaming, contents of polar ginsenosides, such as Rb1, Rc, Rd, Re, and Rg1, were rapidly decreased, whereas less polar ginsenosides such as Rg3, Rg5, Rk1, Rk3, and Rh4 were increased as reported previously. However, ocotillol type saponins, which have no glycosyl moiety at the C-20 position, were relatively stable on steaming. The radical scavenging activity was increased continuously up to 20 h of steaming. Similarly, the antiproliferative activity against A549 lung cancer cells was also increased. Conclusion: It seems that the antiproliferative activity is closely related to the contents of ginsenoside Rg3, Rg5, and Rk1.

• Korean Journal of Pharmacognosy
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• v.46 no.3
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• pp.173-188
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• 2015

We have conducted a comprehensive literature review regarding the chemical constituents and biological activities of Korean black ginseng(Panax ginseng C. A. Meyer), three to nine times-steamed and dried ginseng, which shows strong black color through Maillared browning reaction. It has been reported that some chemically deglycosylated and transformed saponins are obtained from black ginseng as artifacts produced during intensive steaming. They have been known to be ginsenosides Rg3, Rg4, Rg5, Rg6, Rh1, Rh2, Rh4, Rk1 and Rk3, quite different from those of red ginseng, among which ginsenosides Rg3, Rg5 and Rk1 are considered to be major components. And also, black ginseng has been recently found to demonstrate anticancer, recovery from learning and memory damages, hypontensive, antidiabetic, antiobesitic, tonic and antiatopic activities, together with antioxidative and exercise performance improving activities, exhibiting their effects to be a little bit stronger than those of red ginseng. These findings suggest that black ginsng might play an important role in the development of promising functional foods and drugs from the viewpoint of the chemical composition and biological activities of black ginseng with a distinction from those of white and red ginsengs. In this review, the authors will survey and evaluate further functions of black ginseng with a focus on its physicochemical properties and biological activities.

• Korean Journal of Pharmacognosy
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• v.43 no.2
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• pp.152-156
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• 2012

This study compared the contents of ginseng prosapogenin depending on the extracting conditions of Ginseng Radix palva(Panax ginseng) to provide basic information for developing Ginseng Radix palva-based functional foods. Our findings show that the content of crude saponin peaked at 18 hours of extraction and when extracted twice at $100^{\circ}C$ (GRP-18). However, the content of total saponin reached its height at 6 hours of extraction at $100^{\circ}C$ (GRP-6) and when extracted twice. On the other hand, the content of ginsenoside $Rg_3$, $Rg_5$ and $Rk_1$ from Red and Black ginseng reached their heights at 18 hours of extraction, followed by 72 hours and 15 hours of extraction at $100^{\circ}C$. And at $100^{\circ}C$ the main prosapogenin of the content of Black ginseng ginsenoside $Rg_5$ and $Rk_1$ reached their heights at 18 hours of extraction, followed by 72 hours and 15 hours of extraction.

• Korean Journal of Remote Sensing
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• v.37 no.6_1
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• pp.1739-1756
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• 2021

Atmospheric nitrogen dioxide (NO₂) is mainly caused by anthropogenic emissions. It contributes to the formation of secondary pollutants and ozone through chemical reactions, and adversely affects human health. Although ground stations to monitor NO₂ concentrations in real time are operated in Korea, they have a limitation that it is difficult to analyze the spatial distribution of NO₂ concentrations, especially over the areas with no stations. Therefore, this study conducted a comparative experiment of spatial interpolation of NO₂ concentrations based on two linear-regression methods(i.e., multi linear regression (MLR), and regression kriging (RK)), and two machine learning approaches (i.e., random forest (RF), and support vector regression (SVR)) for the year of 2020. Four approaches were compared using leave-one-out-cross validation (LOOCV). The daily LOOCV results showed that MLR, RK, and SVR produced the average daily index of agreement (IOA) of 0.57, which was higher than that of RF (0.50). The average daily normalized root mean square error of RK was 0.9483%, which was slightly lower than those of the other models. MLR, RK and SVR showed similar seasonal distribution patterns, and the dynamic range of the resultant NO₂ concentrations from these three models was similar while that from RF was relatively small. The multivariate linear regression approaches are expected to be a promising method for spatial interpolation of ground-level NO₂ concentrations and other parameters in urban areas.

• Journal of applied mathematics & informatics
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• v.26 no.1_2
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• pp.135-149
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• 2008

Many deterministic systems are described by Ordinary differential equations and can often be improved by including stochastic effects, but numerical methods for solving stochastic differential equations(SDEs) are required, and work in this area is far less advanced than for deterministic differential equations. In this paper,first we follow [7] to describe Runge-Kutta methods with order 2 from Taylor approximations in the weak sense and present two well known Runge-Kutta methods, RK2-TO and RK2-PL. Then we obtain a new 3-stage explicit Runge-Kutta with order 2 in weak sense and compare the numerical results among these three methods.

• Kyungpook Mathematical Journal
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• v.56 no.1
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• pp.69-81
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• 2016

For a positive integer k, a k-rainbow dominating function of a digraph D is a function f from the vertex set V (D) to the set of all subsets of the set $\{1,2,{\ldots},k\}$ such that for any vertex $v{\in}V(D)$ with $f(v)={\emptyset}$ the condition ${\cup}_{u{\in}N^-(v)}$ $f(u)=\{1,2,{\ldots},k\}$ is fulfilled, where $N^-(v)$ is the set of in-neighbors of v. A set $\{f_1,f_2,{\ldots},f_d\}$ of k-rainbow dominating functions on D with the property that $\sum_{i=1}^{d}{\mid}f_i(v){\mid}{\leq}k$ for each $v{\in}V(D)$, is called a k-rainbow dominating family (of functions) on D. The maximum number of functions in a k-rainbow dominating family on D is the k-rainbow domatic number of D, denoted by $d_{rk}(D)$. In this paper we initiate the study of the k-rainbow domatic number in digraphs, and we present some bounds for $d_{rk}(D)$.

• Korean Journal of Pharmacognosy
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• v.45 no.4
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• pp.320-325
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• 2014

The purpose of this study is to develop a new preparation process of Notoginseng root(Panax notoginseng) extracts having high concentrations of ginsenoside $Rg_3$, $Rg_5$, $Rk_1$ and $Rh_4$, a special component of Red and Black ginseng(Panax ginseng). Chemical transformation from ginseng saponin to prosapogenin was analyzed by the HPLC. Extracts of Notoginseng root was processed under several treatment conditions including microwave and vinegar(about 14% acidity) treatments. Results of those treatments showed that the quantity of ginsenoside $Rg_3$ increased by over 7.6% at 15 minutes of pH 2~4 vinegar and microwave treatments. The results of processing with MPN-15 indicate that the microwave and vinegar(about 14% acidity) processed Notoginseng root extracts that had gone through 15-minute treatments were found to contain the largest amount of ginsenoside $Rg_3$(7.639%), $Rg_5$(6.061%), $Rk_1$(1.516%) and $Rh_4$(1.599). It is thought that such results provide basic information in preparing Notoginseng root extracts with functionality enhanced.