Active Matter The transport of ordinary fluids tends to be driven by pressure differentials, whereas for active or biological matter, transport may be isotropic or governed by the presence of specific chemical gradients. Wu et al. analyzed the emergence of spontaneous directional flows in active fluids containing a suspension of microtubules and clusters of the molecular motor kinesin, confined in a variety of microfluidic geometries (see the Perspective by Morozov). When confined in periodic toroidal channels and cylindrical domains, the flow was organized and persisted in a unidirectional motion, either clockwise or counterclockwise. Oddly, this behavior was independent of scale; as long as the aspect ratio of the geometry was chosen appropriately, flows were observed for a wide range of system dimensions. Science , this issue p. [eaal1979][1]; see also p. [1262][2] [1]: /lookup/doi/10.1126/science.aal1979 [2]: /lookup/doi/10.1126/science.aam8998

中文翻译：

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顺应潮流变化

活性物质 普通流体的运输往往由压差驱动，而对于活性物质或生物物质，运输可能是各向同性的或受特定化学梯度的存在控制。吴等人。分析了包含微管悬浮液和分子运动驱动蛋白簇的活性流体中自发定向流动的出现，这些流体被限制在各种微流体几何结构中（参见 Morozov 的观点）。当限制在周期性环形通道和圆柱形域中时，流动以顺时针或逆时针方向的单向运动被组织和持续。奇怪的是，这种行为与规模无关。只要适当地选择几何形状的纵横比，就观察到流动的流动系统尺寸。科学，这个问题 p。[eaal1979][1]; 另见第。[1262][2][1]：/lookup/doi/10.1126/science.aal1979 [2]：/lookup/doi/10.1126/science.aam8998