DISTRIBUTED FORMATION CONTROL OF HOMOGENEOUS VEHICLE PLATOON CONSIDERING VEHICLE DYNAMICS

Liwei Xu,Weichao Zhuang,Guodong Yin,Chentong Bian 한국자동차공학회 2019 International journal of automotive technology Vol.20 No.6

Vehicle dynamics plays a significant role on the formation of a vehicle platoon, especially at high speed condition. This paper proposes a distributed platoon formation framework for homogeneous autonomous vehicles which takes the vehicle dynamics into consideration. The boundaries of vehicle stability are firstly calculated by considering both lateral dynamics and actuator saturation. By combining the stability boundaries with multi-objective flocking (MOF) algorithm, a distributed formation controller is designed, which can form the vehicle platoon with high cruising speed steadily and rapidly. In addition, a low-level tracking controller is proposed to constitute a hierarchical control architecture which can achieve stable and accurate formation of platoon. Simulation results show the proposed platoon formation controller achieves safe, stable and rapid platoon formation than the traditional MOF-based formation controller which does not consider the vehicle dynamics.

Mechanism and kinetics of esterification of adipic acid and ethylene glycol by tetrabutyl titanate catalyst

Liwei Chen,Jumei Xu,Weilan Xue,Zuoxiang Zeng 한국화학공학회 2018 Korean Journal of Chemical Engineering Vol.35 No.1

An eight-step mechanism of esterification reaction between adipic acid (AA) and ethylene glycol (EG) catalyzed by tetrabutyl titanate [Ti(OBu)4] was studied in detail. The kinetic data for the esterification reaction between AA and EG catalyzed by tetrabutyl titanate [Ti(OBu)4] were measured in the temperature range of 403 K-433 K. A second- order kinetic model was established, and the model parameters were obtained through an optimization procedure by minimizing the value differences between the simulated component concentrations in the reaction system with the experimental ones. The results demonstrate that the model is suitable for the esterification reaction between AA and EG catalyzed by tetrabutyl titanate [Ti(OBu)4]. Furthermore, the esterification reaction rate increases with the increase of reaction temperature, concentration of catalyst and the initial reactant ratio of EG to AA.

DsbM, a Novel Disulfide Oxidoreductase Affects Aminoglycoside Resistance in Pseudomonas aeruginosa by OxyR-Regulated Response

Xuehan Wang,Mingxuan Li,Liwei Liu,Rui Mou,Xiuming Zhang,Yanling Bai,Haijin Xu,Mingqiang Qiao 한국미생물학회 2012 The journal of microbiology Vol.50 No.6

A Pseudomonas aeruginosa mutant strain M122 was isolated from a Mu transposon insertion mutant library. In our prophase research, we have found that PA0058, a novel gene encodes a 234-residue conserved protein, was disrupted in the M122 mutant. In this study, the bacteriostatic experiment in vitro indicates that M122 has abnormally high aminoglycoside resistance. We expressed PA0058 in E. coli and found that PA0058 oxidizes and reduces disulfide. This biochemical characterization suggests that PA0058 is a novel disulfide oxidoreductase. Hence, the protein was designated as DsbM. Microarray analysis of the M122 mutant showed its unusual phenotype might be related to the bacterial antioxidant defense system mediated by the oxyR regulon. Meanwhile, we detected –SH content in the periplasm of M122 and wild strain and found a lower –SH/S–S ratio in M122. Therefore, we consider that the loss of dsbM function decreased the –SH/S–S ratio, which then prolongs the OxyR-regulated response, thereby conferring high aminoglycoside resistance to the M122 mutant strain. Our findings have important implications for understanding the mechanisms underlying aminoglycoside resistance in P. aeruginosa.

Panax ginseng total protein promotes proliferation and secretion of collagen in NIH/3T3 cells by activating extracellular signal-related kinase pathway

Chen, Xuenan,Wang, Manying,Xu, Xiaohao,Liu, Jianzeng,Mei, Bing,Fu, Pingping,Zhao, Daqing,Sun, Liwei The Korean Society of Ginseng 2017 Journal of Ginseng Research Vol.41 No.3

Background: Recently, protein from ginseng was studied and used for the treatment of several kinds of diseases. However, the effect of ginseng total protein (GTP) on proliferation and wound healing in fibroblast cells remains unclear. Methods: In this study, cell viability was analyzed using the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay. Cell cycle distribution was analyzed by flow cytometer. The levels of transforming growth factor ${\beta}1$, vascular endothelial growth factor, and collagens were analyzed by enzyme-linked immunosorbent assay and immunofluorescence staining. The expressions of cyclin A, phosphorylation of extracellular signal-related kinase (p-ERK1/2), and ERK1/2 were analyzed by Western blotting. Results: Our results showed that GTP promoted cell proliferation and increased the percentage of cells in S phase through the upregulation of cyclin A in NIH/3T3 cells. We also found that GTP induced the secretion of type I collagen, and promoted the expression of other factors that regulate the synthesis of collagen such as transforming growth factor ${\beta}1$ and vascular endothelial growth factor. In addition, the phosphorylation of ERK1/2 at Thr202/Tyr204 was also increased by GTP. Conclusion: Our studies suggest that GTP promoted proliferation and secretion of collagen in NIH/3T3 cells by activating the ERK signal pathway, which shed light on a potential function of GTP in promoting wound healing.

Phenolic acids in Panax ginseng inhibit melanin production through bidirectional regulation of melanin synthase transcription via different signaling pathways

Jianzeng Liu,Xiaohao Xu,Jingyuan Zhou,Guang Sun,Zhenzhuo Li,Lu Zhai,Jing Wang,Rui Ma,Daqing Zhao,Rui Jiang,Liwei Sun 고려인삼학회 2023 Journal of Ginseng Research Vol.47 No.6

Background: Our previous investigation indicated that the preparation of Panax ginseng Meyer(P. ginseng) inhibited melanogenesis. It comprised salicylic acid (SA), protocatechuic acid (PA), p-coumaricacid (p-CA), vanillic acid (VA), and caffeic acid (CA). In this investigation, the regulatory effects ofP. ginseng phenolic acid monomers on melanin production were assessed. Methods: In vitro and in vivo impact of phenolic acid monomers were assessed. Results: SA, PA, p-CA and VA inhibited tyrosinase (TYR) to reduce melanin production, whereas CA hadthe opposite effects. SA, PA, p-CA and VA significantly downregulated the melanocortin 1 receptor(MC1R), cycle AMP (cAMP), protein kinase A (PKA), cycle AMP-response element-binding protein (CREB),microphthalmia-associated transcription factor (MITF) pathway, reducing mRNA and protein levels ofTYR, tyrosinase-related protein 1 (TYRP1), and TYRP2. Moreover, CA treatment enhanced the cAMP, PKA,and CREB pathways to promote MITF mRNA level and phosphorylation. It also alleviated MITF proteinlevel in a-MSH-stimulated B16F10 cells, comparable to untreated B16F10, increasing the expression ofphosphorylation glycogen synthase kinase 3b (p-GSK3b), b-catenin, p-ERK/ERK, and p-p38/p38. Furthermore, the GSK3b inhibitor promoted p-GSK3b and p-MITF expression, as observed in CA-treatedcells. Moreover, p38 and ERK inhibitors inhibited CA-stimulated p-p38/p38, p-ERK/ERK, and p-MITFincrease, which had negative binding energies with MC1R, as depicted by molecular docking. Conclusion: P. ginseng roots' phenolic acid monomers can safely inhibit melanin production by bidirectionallyregulating melanin synthase transcription. Furthermore, they reduced MITF expression viaMC1R/cAMP/PKA signaling pathway and enhanced MITF post-translational modification via Wnt/mitogen-activated protein kinase signaling pathway.

Proteomic analysis of amino acid metabolism differences between wild and cultivated Panax ginseng

Hang Sun,Fangbing Liu,Liwei Sun,Jianzeng Liu,Manying Wang,Xuenan Chen,Xiaohao Xu,Rui Ma,Kai Feng,Rui Jiang 고려인삼학회 2016 Journal of Ginseng Research Vol.40 No.2

Background: The present study aimed to compare the relative abundance of proteins and amino acid metabolites to explore the mechanisms underlying the difference between wild and cultivated ginseng (Panax ginseng Meyer) at the amino acid level. Methods: Two-dimensional polyacrylamide gel electrophoresis and isobaric tags for relative and absolute quantitation were used to identify the differential abundance of proteins between wild and cultivated ginseng. Total amino acids in wild and cultivated ginseng were compared using an automated amino acid analyzer. The activities of amino acid metabolism-related enzymes and the contents of intermediate metabolites between wild and cultivated ginseng were measured using enzyme-linked immunosorbent assay and spectrophotometric methods. Results: Our results showed that the contents of 14 types of amino acids were higher in wild ginseng compared with cultivated ginseng. The amino acid metabolism-related enzymes and their derivatives, such as glutamate decarboxylase and S-adenosylmethionine, all had high levels of accumulation in wild ginseng. The accumulation of sulfur amino acid synthesis-related proteins, such as methionine synthase, was also higher in wild ginseng. In addition, glycolysis and tricarboxylic acid cycle-related enzymes as well as their intermediates had high levels of accumulation in wild ginseng. Conclusion: This study elucidates the differences in amino acids between wild and cultivated ginseng. These results will provide a reference for further studies on the medicinal functions of wild ginseng.

Panax ginseng total protein promotes proliferation and secretion of collagen in NIH/3T3 cells by activating extracellular signal-related kinase pathway

Xuenan Chen,Manying Wang,Xiaohao Xu,Jianzeng Liu,Bing Mei,Pingping Fu,Da-Qing Zhao,Liwei Sun 고려인삼학회 2017 Journal of Ginseng Research Vol.41 No.3

Background: Recently, protein from ginseng was studied and used for the treatment of several kinds of diseases. However, the effect of ginseng total protein (GTP) on proliferation and wound healing in fibroblast cells remains unclear. Methods: In this study, cell viability was analyzed using the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide] assay. Cell cycle distribution was analyzed by flow cytometer. The levels of transforming growth factor b1, vascular endothelial growth factor, and collagens were analyzed by enzyme-linked immunosorbent assay and immunofluorescence staining. The expressions of cyclin A, phosphorylation of extracellular signal-related kinase (p-ERK1/2), and ERK1/2 were analyzed byWestern blotting. Results: Our results showed that GTP promoted cell proliferation and increased the percentage of cells in S phase through the upregulation of cyclin A in NIH/3T3 cells. We also found that GTP induced the secretion of type I collagen, and promoted the expression of other factors that regulate the synthesis of collagen such as transforming growth factor b1 and vascular endothelial growth factor. In addition, the phosphorylation of ERK1/2 at Thr202/Tyr204 was also increased by GTP. Conclusion: Our studies suggest that GTP promoted proliferation and secretion of collagen in NIH/3T3 cells by activating the ERK signal pathway, which shed light on a potential function of GTP in promoting wound healing.

Experimental and Theoretical Investigations of PAN Molecular Weight Increase in Precipitation Polymerization as a Function of H<SUB>2</SUB>O/DMSO Ratio

Jing Zhang,Fengjing Bu,Yongqiang Dai,Liwei Xue,Zhixian Xu,Seung-Kon Ryu,Riguang Jin 한국탄소학회 2010 Carbon Letters Vol.11 No.1

The precipitation polymerization of acrylonitrile (AN) was carried out in a mixture solution of dimethyl sulfoxide (DMSO) and water at 50~65℃ using α,α'-azobisisobutyronitrile (AIBN) as an initiator. The increased molecular weight polyacrylonitrile (PAN) was prepared with increasing the H2O/DMSO ratio from 10/90 to 80/20. The viscosity average molecular weight of H2O/DMSO solvent was 4.4 times larger than that of H2O/DMF solvent, and precipitation polymerization was accelerlated due to the far decreased chain transfer effect of DMSO. Based on the experimental results, the increased PAN molecular weight was regarded as the summation of two mechanisms: i) particle-particle aggregation and ii) particle-radical attachment. The theoretical equation derived from the mechanisms was well coincided with the experimental results showing the linear relationship between the viscosity average molecular weight and the H2O/DMSO ratio.

Novel Payload Parameter Sensitivity Analysis on Observation Accuracy of Lightweight Electric Vehicles

Jin Xianjian,Wang Zhaoran,Yang Junpeng,Xu Liwei,Yin Guodong 한국자동차공학회 2023 International journal of automotive technology Vol.24 No.5

Lightweight electric vehicles (LEVs) possess great advantages in the viewpoint of fuel consumption, environment protection and traffic mobility. However, due to the drastic reduction of vehicle weights and body size, the effects of payload parameter variation in LEV control and estimation system become much more pronounced and have to be systematically analysed. This paper proposes a novel payload parameter sensitivity analysis to provide quantitative insight into the sensitivity of payload parameter on the LEV system responses and state estimation. The analysis-oriented LEV dynamic model considering payload parameter variations is developed. Then, the trajectory sensitivity index of the influential parameters is defined and derived with the perturbation approach, the median method is used to improve the calculation accuracy for the trajectory sensitivity of payload parameter. Finally, the extended Kalman filter is designed to show the effect and importance of the sensitive payload parameters on the observation accuracy, the payload parameter variations along with fundamental state estimation such as vehicle sideslip angle, longitudinal velocity and vehicle roll angle are analysed. Simulation results with Matlab/Simulink-Carsim® show that the proposed method can accurately describe the relationship between the vehicle payload parameters and system state estimation, which is helpful to design and evaluate LEV controller and observer performances.

Proteomic analysis of amino acid metabolism differences between wild and cultivated Panax ginseng

Sun, Hang,Liu, Fangbing,Sun, Liwei,Liu, Jianzeng,Wang, Manying,Chen, Xuenan,Xu, Xiaohao,Ma, Rui,Feng, Kai,Jiang, Rui The Korean Society of Ginseng 2016 Journal of Ginseng Research Vol.40 No.2

Background: The present study aimed to compare the relative abundance of proteins and amino acid metabolites to explore the mechanisms underlying the difference between wild and cultivated ginseng (Panax ginseng Meyer) at the amino acid level. Methods: Two-dimensional polyacrylamide gel electrophoresis and isobaric tags for relative and absolute quantitation were used to identify the differential abundance of proteins between wild and cultivated ginseng. Total amino acids in wild and cultivated ginseng were compared using an automated amino acid analyzer. The activities of amino acid metabolism-related enzymes and the contents of intermediate metabolites between wild and cultivated ginseng were measured using enzyme-linked immunosorbent assay and spectrophotometric methods. Results: Our results showed that the contents of 14 types of amino acids were higher in wild ginseng compared with cultivated ginseng. The amino acid metabolism-related enzymes and their derivatives, such as glutamate decarboxylase and S-adenosylmethionine, all had high levels of accumulation in wild ginseng. The accumulation of sulfur amino acid synthesis-related proteins, such as methionine synthase, was also higher in wild ginseng. In addition, glycolysis and tricarboxylic acid cycle-related enzymes as well as their intermediates had high levels of accumulation in wild ginseng. Conclusion: This study elucidates the differences in amino acids between wild and cultivated ginseng. These results will provide a reference for further studies on the medicinal functions of wild ginseng.