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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.
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.
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.