分子刚度对膜锚定受体-配体结合动力学影响的理论与模拟研究

人体内大部分生物学过程都离不开细胞黏附.细胞黏附行为主要由锚定于细胞膜上的特异性分子（又称受体和配体）的结合动力学关系来决定.已有研究表明，特异性分子的结合关系受外力及细胞膜波动等多种因素影响.然而，特异性分子刚度对细胞膜锚定受体 配体结合关系的影响机制仍不清楚.近期关于新冠病毒强传染力的研究表明，特异性黏附分子刚度对病毒与细胞结合具有重要影响.该文通过建立生物膜黏附的粗粒度模型，借助分子模拟和理论分析来研究分子刚度在黏附中的作用.结果表明，始终存在一个最佳膜间距及最佳分子刚度值，使得黏附分子亲和力和结合动力学参数达到最大值.这项研究不仅能加深人们对细胞黏附的认知，还有助于指导药物设计、疫苗研发等.     

气流作用下气道组织变形的流固耦合研究

悬雍垂腭咽成形术(UPPP)是一种治疗阻塞性睡眠呼吸暂停(OSA)的常规外科手术,然而由于手术作用机制仍不清楚,手术成功率较低.现有的研究大多忽略了患者上气道的具体形态以及呼吸作用下气道软组织的弹性变形,不足以有效指导手术治疗.文章基于OSA患者在术前、术后的CT扫描图像,构建了精确的三维上气道模型,通过双向流固耦合(FSI)计算,模拟研究了呼吸作用下上气道软组织的弹性变形和气道内气流流动情况.比较手术成功案例和失败案例中OSA患者上气道的流速、压力分布及气道弹性变形情况,从气道流体流动状态和气道软组织变形的角度解释了OSA的发生原因与手术作用机制.结果表明,最小横截面积尺寸并不是UPPP手术成功与否的决定性因素,成功的手术应当是减轻气道壁负压力程度、降低气道进出口之间的压降.此外,使用双向FSI方法,文章进一步构建了简化的人体二维软腭模型,探究了软腭弹性模量对吸气过程的影响,发现当软腭的弹性模量在0.5～1.5 MPa的范围内时,刚度更小的软腭会改善流场的流动情况,但也更易发生变形塌陷.文章所发展的流固模型为个性化预测手术效果提供了研究工具.     

Multi-Scale Prediction of Thermal and Mechanical Properties of C/SiC Braided Composites北大核心CSCD

C/ SiC composites have been widely used in aerospace, national defense, and chemical industries due to their excellent mechanical and thermal properties. Accurate knowledge about the mechanical/ thermal properties of C/ SiC composites is very important for their efficient application in related fields. Based on the representative volume element (RVE) and periodic boundary conditions, a micro/ meso single-cell model for C/ SiC composites was established in view of the non-uniform and multi-scale characteristics of fiber bundles, such as the volume fraction, the interweaving mode, and the weaving dimension. The finite element software ABAQUS was used to predict the micro-scale thermal and mechanical properties of the fiber bundle, and the fiber bundle properties were introduced into the mesoscopic model to analyze and obtain the macroscopic thermal and mechanical properties of the composite. Based on this multi-scale correlation analysis method, the thermal conductivity and thermal expansion coefficient of fiber bundles and C/ SiC composites were further studied at the operating temperatures ranging from 27~1 227 ℃. The study has certain guiding significance for the application of C/ SiC composites in engineering. © 2023 Editorial Office of Applied Mathematics and Mechanics. All rights reserved.