新生婴儿与老年人红细胞物理特性对比实验

目的通过比较新生婴儿与80岁以上老年人红细胞物理特性(细胞表面积、体积和剪切弹性模量)及与总胆固醇、糖化血红蛋白等生理生化参数的相关关系,分析不同年龄和生化参数对红细胞物理特性的影响。方法采用微量吸管技术测量新生婴儿和80岁以上老年人的红细胞表面积、体积和剪切弹性模量,对数据进行统计分布分析、相关性分析和回归分析。结果80岁以上老年人红细胞体积、表面积、剪切弹性模量均值都比新生婴儿红细胞相应参数要小,同年龄组内单个人样本间的红细胞力学参数均值相差不大。新生儿红细胞几何参数分布与老人相比更为集中,而剪切弹性模量分布比老年人红细胞的更分散。新生婴儿红细胞物理特性与总胆固醇和出生孕周相关性高;老年人红细胞物理特性与舒张压和糖化血红蛋白的相关性高。结论新生婴儿与80岁以上老年人的红细胞物理特性有明显差异,影响不同年龄红细胞物理特性的生化指标也不同。

Non-Stokes drag coefficient in single-particle electrophoresis:New insights on a classical problem

We measured the intrinsic electrophoretic drag coefficient of a single charged particle by optically trapping the particle and applying an AC electric field,and found it to be markedly different from that of the Stokes drag.The drag coefficient,along with the measured electrical force,yield a mobility-zeta potential relation that agrees with the literature.By using the measured mobility as input,numerical calculations based on the Poisson-Nernst-Planck equations,coupled to the Navier-Stokes equation,reveal an intriguing microscopic electroosmotic flow near the particle surface,with a well-defined transition between an inner flow field and an outer flow field in the vicinity of electric double layer’s outer boundary.This distinctive interface delineates the surface that gives the correct drag coefficient and the effective electric charge.The consistency between experiments and theoretical predictions provides new insights into the classic electrophoresis problem,and can shed light on new applications of electrophoresis to investigate biological nanoparticles.

固液界面双电荷层结构的一个界面势模型

当液体受限在纳米尺度下时,会呈现出跟宏观尺度下完全不同的输运性质。这些新的性质可以被应用于很多领域,譬如对生物体中体液输运的研究,液体抽运,药物的混合和分离,以及离子和胶体颗粒的选择等领域。为了充分利用这些新性质,需要对纳米液体中最基本的双电荷层结构有深刻认识。文章回顾了传统的泊松—玻尔兹曼方程对双电荷层结构中液体离子分布的计算,指出了其中的不足,并提出一种基于液体电荷保持中性的固液表面势模型。