Pharmacokinetics and Biodistribution of Surface Modification Polymeric Nanoparticles

Liu, Mingxing,Li, Huifang,Luo, Guoan,Liu, Qingfei,Wang, Yiming 대한약학회 2008 Archives of Pharmacal Research Vol.31 No.4

The objective of this study is to investigate the pharmacokinetics and biodistribution of free breviscapine (BVP) and coated BVP-loaded poly (D, L-lactic acid) nanoparticles (BVP-PLA-NPs) in rats after i.v. administration. Coated BVP-PLA-NPs were prepared by the spontaneous emulsification solvent diffusion method and characterized. The BVP content in the NPs, the biological samples and in vitro release was measured by the high-performance liquid chromatography (HPLC). The mean sizes of coated BVP-PLA-NPs were 177 and 319 nm with a narrow distribution and smooth sphere shapes, entrapment efficiency of 86.9% and 93.1%, respectively. Drug release profiles in phosphate buffer and plasma exhibited a biphasic release phenomenon. After i.v. administration of free BVP and NPs suspensions in rats, area under plasma concentration-time curve and elimination $t_{1/2}$ were increased 9.3-fold and 10.9-fold for 177 nm of NPs, and 4.4-fold and 17.1-fold for 319 nm of NPs compared with that of free BVP, respectively. NPs were mainly distributed in liver, spleen, heart and brain. In addition, NPs could penetrate blood brain barrier (BBB) and the particle size had some effect on pharmacokinetics and biodistribution. Coated BVP-PLA-NPs could effectively avoid the capture by the reticuloendothelial system and prolong the half-life of BVP. Moreover, these NPs could penetrate BBB and enhance the accumulation of BVP in brain.

Dynamic Output Feedback Control and Guaranteed Cost Finite-time Boundedness for Uncertain Switched Linear Systems

Mingxing Liu,Baowei Wu,Yue-E Wang,Lili Liu 제어·로봇·시스템학회 2023 International Journal of Control, Automation, and Vol.21 No.2

This paper is concerned with dynamic quantized output feedback and event-triggered guaranteed cost finite-time H∞ control for uncertain switched linear systems with exogenous disturbance. First, one mode-dependent periodic event-triggered strategy is designed, which means that each subsystem has its own event-triggered mechanism. Meanwhile, the periodic detection of the error greatly reduces the sampling number and avoids the appearance of Zeno behavior. Second, considering the state information of the system is difficult to obtain completely, dynamic quantized output feedback controllers based on logarithmic quantizer are used to stabilize the switched system. Besides, combine the multiple Lyapunov functionals and the average dwell time condition, the sufficient condition of finite-time boundedness with H∞ performance level is obtained for the uncertain switched system. Finally, the effectiveness of the proposed method is verified a practical example.

Pharmacokinetics and Biodistribution of Surface Modification Polymeric Nanoparticles

Mingxing Liu,Huifang Li,Guoan Luo,Qingfei Liu,Yiming Wang 대한약학회 2008 Archives of Pharmacal Research Vol.31 No.4

The objective of this study is to investigate the pharmacokinetics and biodistribution of free breviscapine (BVP) and coated BVP-loaded poly (D, L-lactic acid) nanoparticles (BVP-PLANPs) in rats after i.v. administration. Coated BVP-PLA-NPs were prepared by the spontaneous emulsification solvent diffusion method and characterized. The BVP content in the NPs, the biological samples and in vitro release was measured by the high-performance liquid chromatography (HPLC). The mean sizes of coated BVP-PLA-NPs were 177 and 319 nm with a narrow distribution and smooth sphere shapes, entrapment efficiency of 86.9% and 93.1%, respectively. Drug release profiles in phosphate buffer and plasma exhibited a biphasic release phenomenon. After i.v. administration of free BVP and NPs suspensions in rats, area under plasma concentration-time curve and elimination t1/2 were increased 9.3-fold and 10.9-fold for 177 nm of NPs, and 4.4-fold and 17.1-fold for 319 nm of NPs compared with that of free BVP, respectively. NPs were mainly distributed in liver, spleen, heart and brain. In addition, NPs could penetrate blood brain barrier (BBB) and the particle size had some effect on pharmacokinetics and biodistribution. Coated BVP-PLA-NPs could effectively avoid the capture by the reticuloendothelial system and prolong the half-life of BVP. Moreover, these NPs could penetrate BBB and enhance the accumulation of BVP in brain.

Analysis of the repeatability of a deployable space tri-prism mast based on the Monte Carlo method

Mingxing Gao,Rongqiang Liu,Hongwei Guo,Zongquan Deng 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.3

Space deployable mast, which is a supporting mechanism, especially for a space telescope, requires high repeatability. In this study, a deployed space tri-prism mast was taken as the research object, and the change of a tensional cable’s tension force was equivalent to an external load. Based on the accurate stiffness model of the mast, the repeatability of the tri-prism mast was calculated by using the Monte Carlo method. Then, the influences of the number of units, the change in the tension force, the thickness of the linkage, and the radius of the tensional cable on the repeatability of the tri-prism mast were studied. Moreover, the correctness of the analytical model was verified by the repeatability experiments. Results demonstrated that the proposed method could be used to analyze the repeatability of tri-prism mast. This study provided references and suggestions for the design of high-precision space deployable mast.

Effect of Particle Breakage and Interlocking on Strength and Dilatancy Characteristics of Calcareous Sands

Mingxing Luo,Jiru Zhang,Xiaoxuan Liu,Cai Wu 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.8

Studies show that the shear strength of angular-shaped calcareous sand is mainly affected by dilatancy, interparticle locking, and particle breakage. In the present study, a series of consolidated-drained triaxial compression tests on calcareous sands are carried out to investigate the strength impacts of dilatancy, interparticle locking, and particle breakage. It is found that as the stress level increases, the friction angle difference reflecting the effect of the particle breakage increases. In contrast, the friction angle difference reflecting the interparticle locking and dilatancy effect decreases gradually. Moreover, the critical stress ratio of the high-angled calcareous sands decreases, which may be attributed to particle breakage. The obtained results demonstrate that when the stress level exceeds a certain value, the critical stress ratio remains constant. Then the correlation between the particle breakage, interparticle locking, and dilatancy effects in the shear strength is studied. Finally, based on the performed analysis on energy dissipation in calcareous sands, a dilatancy model is proposed that covers the particle breakage effect. The performed analyses demonstrate that the proposed model can accurately explain the experimental data.

Correction method for calculating junction temperature considering parasitic effects in SiC MOSFETs

Fan Liu,Mingxing Du,Jinliang Yin,Chao Dong,Ziwei Ouyang 전력전자학회 2023 JOURNAL OF POWER ELECTRONICS Vol.23 No.4

The turn-on change rate of drain current diDS(on)/dt is an electrical parameter that is suitable for the online monitoring of junction temperature in SiC MOSFETs. In practical applications, the change of an external circuit changes the temperature-sensitive characteristic of diDS(on)/dt. In this paper, a SiC MOSFET in a Buck converter is taken as the research object. First, it is theoretically derived and experimentally verified that the power loop inductance and drive loop resistance are parasitic parameters that affect the temperaturesensitive characteristic of diDS(on)/dt. Second, according to the spectrum peak characteristics caused by the drain–source turn-off oscillation voltage of the SiC MOSFET, the theoretical relationship between the diDS(on)/dt temperature-sensitive characteristic and the peak of the drain–source turn-off oscillation voltage is studied. It is concluded that the spectrum peak can reflect the change of the diDS(on)/dt temperature-sensitive characteristic caused by the change of the parasitic parameters. Based on the above research, a model of a modified diDS(on)/dt temperature-sensitive characteristic considering parasitic effect is established in this paper. Through experimental verification, this model can largely eliminate the junction temperature monitoring error caused by the change of the external circuit.

Telerobotic Spinal Surgery Based on 5G Network: The First 12 Cases

Wei Tian,Mingxing Fan,Cheng Zeng,Yajun Liu,Da He,Qi Zhang 대한척추신경외과학회 2020 Neurospine Vol.17 No.1

Objective: The purpose of this study was to determine the efficacy and feasibility of 5th generation wireless systems (5G) telerobotic spinal surgery in our first 12 cases. Methods: A total of 12 patients (5 males, 7 females; age, 23–71 years) with spinal disorders (4 thoracolumbar fractures, 6 lumbar spondylolisthesis, 2 lumbar stenosis) were treated with 5G telerobotic spinal surgery. Sixty-two pedicle screws were implanted. Results: All patients had substantial relief from their symptoms. Screw placements were classified using Gertzbein-Robbins criteria. There were 59 grade A, 3 grade B. Mean operation time was 142.5±46.7 minutes. Mean guiding wire insertion time was 41.3±9.8 minutes. The deviation between the planned and actual positions was 0.76±0.49 mm. No intraoperative adverse event was found. Conclusion: 5G remote robot-assisted spinal surgery is accurate and reliable. We conclude that 5G telerobotic spinal surgery is both efficacious and feasible for the management of spinal diseases with safety.

Guerrilla Capitalism: Revolutionary Legacy, Political Cleavage, and the Preservation of the Private Economy in Zhejiang

Qi Zhang,Mingxing Liu,Victor Shih 동아시아연구원 2013 Journal of East Asian Studies Vol.13 No.3

In this article, we propose a causal relationship between a region’s communist revolutionary legacy before 1949 and the variation in private sector development after 1949. In the case of Zhejiang, the pre-1949 revolutionary experience led to the power struggle between two elite groups, the guerrilla cadre group and the southbound cadre group, in the province after 1949. As the weak side, guerrilla cadres were willing to protect local economic interests in exchange for local popular support, which improved their odds of political survival. As a result, in contrast with counties where the guerrilla forces were historically weak, counties with strong guerrilla forces before 1949 saw significantly more robust private sector development throughout much of the Mao and post-Mao periods. In this article we provide preliminary historical and statistical evidence to support this hypothesis.

A New Model-free Robust Adaptive Control of Cable-driven Robots

Yaoyao Wang,Lufang Liu,Mingxing Yuan,Qingxun Di,Bai Chen,Hongtao Wu 제어·로봇·시스템학회 2021 International Journal of Control, Automation, and Vol.19 No.9

For high performance control of cable-driven robots, a new model-free robust adaptive control is proposed using adaptive proportional-integral-derivative nonsingular fast terminal sliding mode (PID-NFTSM) in this paper. The designed control scheme has three elements, which are time-delay estimation (TDE) and a new PIDNFTSM manifold and a combined adaptive reaching law. The TDE element is applied to achieve the lumped system dynamics and hence founds a practical model-free structure. Meanwhile, a new PID-NFTSM manifold is designed to inherit the advantages of the NFTSM and high-order SM (HOSM) and integral SM (ISM) controls. Because of this design, the PID-NFTSM manifold can effectively ensure the non-singularity and high comprehensive control performance. Then, by combining the fast-TSM-type reaching law and a constant speed one with adaptive gain, we design a new combined adaptive reaching law for performance reinforcement. Benefiting from above three parts, our proposed control is model-free, highly precise and strongly robust. Stability is analyzed using Lyapunov theory. The effectiveness of our control is proved by comparative simulation studies. For high performance control of cable-driven robots, a new model-free robust adaptive control is proposed using adaptive proportional-integral-derivative nonsingular fast terminal sliding mode (PID-NFTSM) in this paper. The designed control scheme has three elements, which are time-delay estimation (TDE) and a new PIDNFTSM manifold and a combined adaptive reaching law. The TDE element is applied to achieve the lumped system dynamics and hence founds a practical model-free structure. Meanwhile, a new PID-NFTSM manifold is designed to inherit the advantages of the NFTSM and high-order SM (HOSM) and integral SM (ISM) controls. Because of this design, the PID-NFTSM manifold can effectively ensure the non-singularity and high comprehensive control performance. Then, by combining the fast-TSM-type reaching law and a constant speed one with adaptive gain, we design a new combined adaptive reaching law for performance reinforcement. Benefiting from above three parts, our proposed control is model-free, highly precise and strongly robust. Stability is analyzed using Lyapunov theory. The effectiveness of our control is proved by comparative simulation studies.

STUDIES ON SYNTHESIS OF METHYL GLYCOLATE AND METHYL METHOXY ACETATE FROM THE COUPLING OF FORMALDEHYDE AND METHYL FORMATE

He, Dehua,Huang, Weiguo,Liu, Jinyao,Zhou, Mingxing,Zhu, Qiming 한국화학공학회 1998 Korean Journal of Chemical Engineering Vol.15 No.5

Catalytic performance of various acids in the coupling reaction of formaldehyde and methyl formate to produce methyl glycolate and methyl methoxy acetate has been studied. The influence of reaction conditions, such as catalyst amount, reaction temperature, reaction time, and molar ratio of formaldehyde to methyl formate, has also been investigated. The results showed that the acid strength had great influence on the reaction, namely, stronger acds had higher activities. It was also found that the reaction temperature and time had significant effect on the reaction, and the preferable conditions were quite different as different acids were used.