论文标题
剪切变薄粘度和粘弹性应力对鞭毛细菌运动的影响
Effects of shear thinning viscosity and viscoelastic stresses on flagellated bacteria motility
论文作者
论文摘要
在非牛顿媒体中游泳的鞭毛细菌的行为仍然是一个矛盾和矛盾的结果。我们报告了牛顿，剪切变薄和粘弹性介质中野生型和平滑速度大肠杆菌的行为，使用三维实时跟踪显微镜测量其轨迹和游泳速度。我们得出的结论是，在较高浓度下，甲壳溶液的速度提高是由于剪切稀释而引起的，分析模型用于支持我们的实验结果。我们认为，剪切引起的正常应力会减少细胞游泳期间的颤动行为，但不会显着影响游泳速度。但是，正常应力在减少鞭毛捆绑时间的时间上起着重要作用，从而改变了游泳速度分布。提出了一个无量纲的数字，“绞缩”（str）被提出并用于表征这种效果。
The behavior of flagellated bacteria swimming in non-Newtonian media remains an area with contradictory and conflicting results. We report on the behavior of wild-type and smooth-swimming E. coli in Newtonian, shear thinning and viscoelastic media, measuring their trajectories and swimming speed using a three dimensional real-time tracking microscope. We conclude that the speed enhancement in Methocel solution at higher concentration is due to shear-thinning and an analytical model is used to support our experimental result. We argue that shear-induced normal stresses reduce the wobbling behavior during cell swimming but do not significantly affect swimming speed. However, the normal stresses play an important role in decreasing the flagellar bundling time which changes the swimming speed distribution. A dimensionless number, the "Strangulation number" (Str) is proposed and used to characterize this effect.
