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骨细胞方向对负荷诱导的骨内液体流动和营养物质运输的影响
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作者 于纬伦 刘昊庭 +6 位作者 霍旭阳 杨风健 杨晓航 楚智媛 时念秋 武晓刚 陈维毅 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2023年第6期179-197,共19页
与年龄或某些骨骼疾病相关的骨细胞空间排列方向的变化引起了研究者们的广泛关注.本研究的目的是通过建立骨细胞相对于骨内流体流动轴偏转0°、30°、45°、60°和90°的骨单元多孔弹性力学模型,证明骨细胞方向对... 与年龄或某些骨骼疾病相关的骨细胞空间排列方向的变化引起了研究者们的广泛关注.本研究的目的是通过建立骨细胞相对于骨内流体流动轴偏转0°、30°、45°、60°和90°的骨单元多孔弹性力学模型,证明骨细胞方向对骨内流体流动的影响.我们假设骨陷窝-小管网络规则排列且均匀分布,且将骨单元定义为由微观尺度水平上的代表性立方周期单元(CPUC)组成.通过计算骨细胞周围骨小管的数量和3D分布来估算骨单元的微观结构参数(渗透率、孔隙率等),并建立骨单元孔隙弹性有限元模型,研究不同边界条件和载荷形式下负载诱导的骨内间质流体流动和骨内营养物质运输.结果表明,在接近正常生理活动的载荷条件下,骨细胞方向对骨单元最大流体压力(p)、最大流体速度(v)和最大流体剪切应力(τ)都有显著的影响.p值和τ值在骨单元壁内呈现不均匀分布,这说明骨细胞方向和骨小管三维分布是预测骨陷窝-小管系统渗透性各向异性程度的重要参数,但骨细胞方向对骨内营养物质运输影响很小.此外,载荷形式和骨陷窝-小管弯曲度对骨单元的液体流动行为的影响大于骨细胞方向对其的影响.这项研究的结果将有助于人们准确量化骨内液体流动行为,并增强对骨的力传导机制的理解. 展开更多
关键词 液体流动 骨细胞 空间排列 网络规则 正常生理活动 骨骼疾病 小管 弯曲度
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Hot-melt extrusion promotes dissolution,extends“spring-parachute”process and inhibits crystallization in supersaturating microparticle systems
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作者 Yanfei Zhang Huifeng Zhang +8 位作者 Huan Yu Yinghui Ma Chengyi Hao Xiaoying Lin Yong Zhang Zhengqiang Li Xianrong Qi Jia Zeng nianqiu shi 《Particuology》 SCIE EI CAS CSCD 2023年第7期35-48,共14页
Despite the potential advantages of amorphism-induced supersaturation,the merit of new amorphiza-tion formation methods on the properties of the amorphous drug including the stability of the amor-phous state,dissoluti... Despite the potential advantages of amorphism-induced supersaturation,the merit of new amorphiza-tion formation methods on the properties of the amorphous drug including the stability of the amor-phous state,dissolution/solubility,supersaturation,and"spring-parachute"process is still poorly understood,particularly for certain amorphous supersaturating drug delivery systems(aSDDS).The present work aimed to explore the detailed merit of current attractive amorphization manufacturing methods(i.g.,hot-melt extrusion(HME)technique)on the property improvement of aSDDS in form of amorphous solid dispersion microparticles by employing a model Bcs II drug nitrendipine and a polyvinylpyrrolidone-based model polymer copovidone.Many asDDS systems were developed by various methods,and their physicochemical properties were characterized by SEM,PXRD and DSC.HME-triggered amorphization induced superior supersaturation by the observation of the highest dissolution and solubility.HME induced the optimal supersaturation duration by the observed greatest extension of"spring-parachute"process(e.g,maximum AUCspring-parachute).HME technique is comparable with other techniques for the stabilization of amorphous state during storage.All aSDDS systems by HME and other methods showed improved long-term stability of the amorphous state in comparison to the pure amorphous drug.Fourier transformation infrared spectroscopy,Noyes-Whitney equation,nucleation theory and Gibbs free energy of transfer(△G)were used to analyze the underlying mechanisms.Mo-lecular mechanism studies indicated that HME caused a stronger crystallization inhibition effect in the asDDS systems than other methods,but molecular interaction is not a dominant mechanism for property enhancement caused by HME.For the mechanism associated with the polymer itself(PVPVA64),it could inhibit the drug recrystallization,solubilize the drug spontaneously and cause the improved molecular interactions in all aSDDS systems.This study provided a deep insight into detailed advantage of HME 展开更多
关键词 Hot-melt extrusion-triggered amorphization Extensionof"spring-parachute"process Promotion of dissolution/solubility Inhibition of crystallization from a supersaturated state Amorphism-based supersaturating drug microparticle systems
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