Dresden 2020 – wissenschaftliches Programm
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BP 18.15: Poster
Dienstag, 17. März 2020, 14:00–16:00, P2/2OG
Fluid flow controls morphological changes — •Noah Ziethen1 and Karen Alim1,2 — 1Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany — 2Technical University of Munich, Garching, Germany
The morphology of biological transport networks is often regarded as a result of optimization under a given demand. As demands may change rapidly in life, biological flow networks continuously adapt. The shear rate inside the flow network is largely assumed to be the control mechanism of this adaptation. However, direct experimental evidence for this hypothesis is still missing, and the theoretical implication of such local adaptation on the network dynamics is not fully understood.
Here, the model organism Physarum polycephalum allows to directly test causality between flow shear rate change and vessel pruning. P. polycephalum forms a network of connected tubes exhibiting a complex oscillatory shuttle streaming inside them. We image and quantify the time evolution of single vessels in Physarum by extracting the vessel diameter evolution and the corresponding flow field using particle image velocimetry. These measurements reveal a time-delayed response in the tube diameter trend on the average flow magnitude, which results in some data sets in a pruning behavior and for others in an oscillatory interplay between the two quantities. Motivated by the experimental result, we build a feedback model taking into account the local minimization of energy dissipation and the coupling to the network, which is able to reproduce the bistability found in the data.