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Advances in the chemistry, pharmacological diversity, and metabolism of 20(R)-ginseng saponins
Chaoming Wang,Juan Liu,Jianqiang Deng,Jiazhen Wang,Weizhao Weng,Hongxia Chu,Qingguo Meng 고려인삼학회 2020 Journal of Ginseng Research Vol.44 No.1
Ginseng has been used as a popular herbal medicine in East Asia for at least two millennia. However,20(R)-ginseng saponins, one class of important rare ginsenosides, are rare in natural products. 20(R)-ginseng saponins are generally prepared by chemical epimerization and microbial transformation from20(S)-isomers. The C20 configuration of 20(R)-ginseng saponins are usually determined by 13C NMR andX-ray single-crystal diffraction. 20(R)-ginseng saponins have antitumor, antioxidative, antifatigue, neuroprotective,and osteoclastogenesis inhibitory effects, among others. Owing to the chemical structureand pharmacological and stereoselective properties, 20(R)-ginseng saponins have attracted a great dealof attention in recent years. In this study, the discovery, identification, chemical epimerization, microbialtransformation, pharmacological activities, and metabolism of 20(R)-ginseng saponins are summarized.
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Advances in the chemistry, pharmacological diversity, and metabolism of 20(R)-ginseng saponins
Wang, Chaoming,Liu, Juan,Deng, Jianqiang,Wang, Jiazhen,Weng, Weizhao,Chu, Hongxia,Meng, Qingguo The Korean Society of Ginseng 2020 Journal of Ginseng Research Vol.44 No.1
Ginseng has been used as a popular herbal medicine in East Asia for at least two millennia. However, 20(R)-ginseng saponins, one class of important rare ginsenosides, are rare in natural products. 20(R)-ginseng saponins are generally prepared by chemical epimerization and microbial transformation from 20(S)-isomers. The C20 configuration of 20(R)-ginseng saponins are usually determined by <sup>13</sup>C NMR and X-ray single-crystal diffraction. 20(R)-ginseng saponins have antitumor, antioxidative, antifatigue, neuroprotective, and osteoclastogenesis inhibitory effects, among others. Owing to the chemical structure and pharmacological and stereoselective properties, 20(R)-ginseng saponins have attracted a great deal of attention in recent years. In this study, the discovery, identification, chemical epimerization, microbial transformation, pharmacological activities, and metabolism of 20(R)-ginseng saponins are summarized.
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Yushen Chen,Xiaolei Deng,Xiaoliang Lin,Shupeng Guo,Shaofei Jiang,Jianqiang Zhou 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.8
In order to predict the thermal deformation of CNC machine tool spindle system more accurately, a method based on multi-source heterogeneous information fusion is proposed. Aiming at the problem that it is difficult to obtain the global information of thermal deformation with a single type of information source, the effective prediction of thermal deformation of spindle system in machining center is realized under the fusion of temperature and vibration signals. First, the combined denoising method of empirical mode decomposition (EMD) and wavelet threshold is used to preprocess the vibration data. Then, the time-domain, frequencydomain, and time-frequency features of vibration signals are extracted, and the feature dimension is reduced based on correlation analysis and kernel principal component analysis (KPCA). After dimensionality reduction, the vibration data and temperature information are fused in the eigenmatrix. The nonlinear prediction of thermal deformation is studied by support vector regression for grid search parameter optimization (GS-SVR) and support vector regression for particle swarm optimization (PSO-SVR) methods. In order to realize the information acquisition of multi-channel temperature, vibration, and verify the effectiveness of the prediction model in the case of information fusion, a specific machining center is taken as the research object and experiments are performed based on multi-channel and heterogeneous signal acquisition. Finally, the prediction results based on different information sources are compared and analyzed. The results show that the thermal deformation of the machine tool obtained by the multi-source heterogeneous information fusion method is consistent with the actual test results. As compared with the predicted performance using only temperature information, the mean square error (MSE) decreased by 0.1663 μm. Therefore, the temperature - vibration information fusion model has higher accuracy in terms of predicting the thermal deformation of the spindle system model.
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Applicability research of round tube CHF mechanistic model in rod bundle channel
Liu, Wei,Peng, Shinian,Shan, Jianqiang,Jiang, Guangming,Liu, Yu,Deng, Jian,Hu, Ying Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.2
In view of the complex geometric structure of the rod bundle channel and the limitation of the current CHF visualization experiment technology, it is very difficult to obtain the rod bundle CHF mechanism directly through the phenomenon of the rod bundle CHF visualization experiment. In order to obtain the applicable CHF mechanism assumption for rod bundle channel, firstly, five most representative DNB type round tube CHF mechanistic models are obtained with evaluation and screening. Then these original round tube CHF mechanistic models based on inlet conditions are converted to local conditions and coupled with subchannel analysis code ATHAS. Based on 5 × 5 full-length rod bundle CHF experimental data independently developed by Nuclear Power Institute of China (NPIC), the applicability research of each model for CHF prediction performance in rod bundle channel is carried out, and the commonness and difference of each model are comparatively studied. The CHF mechanism assumption of superheated liquid layer depletion that is most likely to be applicable for the rod bundle channel is selected and two directions that need to be improved are given. This study provides a reference for the development of CHF mechanistic model in rod bundle channel.
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