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HighlightArabidopsis actin-related protein ARP3 plays a role in amyloplast sedimentation and polar auxin redistribution during root gravitropism.

In this article, we explore the heat transfer of non-Newtonian liquid food in the heating process in a channel connecting a tank. To achieve a rapid heat diffusion, several cylindrical agitators are inserted into the tank. We pay special attention to a Chinese traditional food, i.e. the black sesame paste, which is predicted by the powerlaw model. The fluid flow and heat transfer are investigated numerically, under the impacts of the angular velocity of cylinder, the stirrer size and the rotational direction. Three different settings are investigated: the two-stirrer, the three-stirrer, and the 2 × 2 stirrer settings. Several applicable strategies could be applied to improve the heat transfer in food engineering practices, including changing the size, the rotational velocity, the direction, and the number of stirrers in the heat exchanger.

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Gravitropism in plants is one of the most controversial issues. In the most wildly accepted starch-statolith hypothesis the sedimentation movement of amyloplasts in the gravisensing columella cells primarily triggers the asymmetric distribution of auxin which leads to the differential growth of the plant root. It has been gradually recognized that the inhomogeneous structures in statocytes arising from intracellular components such as cytoskeletons significantly affect the complex movements of amyloplasts and the final gravimorphogenesis. In this letter, we implement a diffusive dynamics measurement and inplanta microrheological analysis of amyloplasts in the wild-type plants and actin cytoskeleton mutants for the first time. We found that the intracellular environment of columella cells exhibits the Zhongyu Zheng

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The self-diffusion problem of Brownian particles under the constraint of quasi-one-dimensional (q1D) channel has raised wide concern. The hydrodynamic interaction (HI) plays an important role in many practical problems and two-body interactions remain dominant under q1D constraint. We measure the diffusion coefficient of individual ellipsoid when two ellipsoidal particles are close to each other by video-microscopy measurement. Meanwhile, we obtain the numerical simulation results of diffusion coefficient using finite element software. We find that the self-diffusion coefficient of the ellipsoid decreases exponentially with the decrease of their mutual distance X when X < X 0 , where X 0 is the maximum distance of the ellipsoids to maintain their mutual influence, X 0 and the variation rate are related to the aspect ratio p = a/b. The mean squared displacement (MSD) of the ellipsoids indicates that the self-diffusion appears as a crossover region, in which the diffusion coefficient increases as the time increases in the intermediate time regime, which is proven to be caused by the spatial variations affected by the hydrodynamic interactions. These findings indicate that hydrodynamic interaction can significantly affect the self-diffusion behavior of adjacent particles and has important implications to the research of microfluidic problems in blood vessels and bones, drug delivery, and lab-on-chip.