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- 저자 : Qingfei Liu (검색결과 4 건)
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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.
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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.
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Nonstructural Influence Factors of Dynamic Load Allowance for Concrete Beam Bridges
Chenguang Liu,Zonglin Wang,Qingfei Gao 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.5
Studies show that nonstructural parameters, such as pavement conditions or load patterns, have greater influences on the dynamic load allowance (DLA) of bridges than structural parameters. For pavement roughness effects, the values of DLA caused by roughness profiles are calculated by a self-compiled program. The results showed that the values of DLA are discrete even if they are caused by roughness profiles that belong to the same power spectral density (PSD) grade. The PSD grade method for pavement conditions has limitations when it is used in the analysis of DLA. Statistical analysis was also carried out on these DLA results. The statistical analysis indicated that the values of DLA followed a normal distribution when they were excited by roughness profiles that belong to the same grade. For the influence of vehicle string loads on DLA, an improved optimization approach based on a genetic algorithm for the largest DLA is presented. A new method is used to calculate the fitness value in the genetic algorithm (GA) method, which could substantially reduce calculation time. The new approach is able to obtain the most unfavorable arrangement of the vehicle string and estimate the largest DLA caused by it.
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Qian Li,Aihong Ji,Huan Shen,Renshu Li,Kun Liu,Xiangming Zheng,Lida Shen,Qingfei Han 한국항공우주학회 2022 International Journal of Aeronautical and Space Sc Vol.23 No.2
The design of a flapping-wing aircraft is mainly inspired by flying animals: to improve the lift and efficiency of flapping-wing aircraft, their wings, an essential part of the aircraft, mimic the configuration and geometric characteristics of flying animals. Herein, we conducted wing parameter optimization experiments by changing the wing-vein layout, aspect ratio (AR), surface area, and leading-edge-rod flexibility of a flapping-wing aircraft having four wings with double wing clap-and-fling effects. The AR and leading-edge-rod flexibility significantly influenced the lift through the aircraft’s clap-and-fling effects. Analyzing the wing deformation and lift fluctuation revealed that the leading-edge-rod flexibility delayed the trailing-edge separation during clapping, resulting in a large lift at the beginning of peeling. A pentagonal wing of 155-mm wing length, 5.0 AR, a 100-mm breaking point, and an 80-mm wing-vein convergence point at the leading-edge-rod near the wing root was deemed the optimal wing design. This optimal wing design was used to build a 30 g flapping-wing aircraft for an outdoor flight test, which could fly for 6.5 min with a 4.5-g load, thus demonstrating the developed prototype’s potential for autonomous flight.
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