Philipp Sebastian Lang

German

Ring polymers - dynamics and behavior in fluid flows
In this project we focus on the behavior of semiflexible and stiff ring polymers using both numeric and anlalytic methods. We determined the relaxation dynamics, which deviate from those of linear filaments, as there exist an additional linear scaling regimes after the t^(3/4) regime. As expected even in the two qualitatively similar regimes quantitative differences arise. We use the knowledge on the relaxation to study the tumbling dynamics of ring polymers in a shear flow in terms of the dimensionless Weissenberg number Wi, and compare the results to those known for the linear case.
To model more complex flows and hydrodynamic interations we attempt to couple a polymer simulation with an SRD.

The mechanics of the bacterial cytoskeleton
Only in the last decade the existence of the bacterial cytoskeleton was discovered. In this project we focus on the actin-homolog MreB, which is known to build actin like filaments, but interestingly shows a helix-like localization in the cell. We attempt we determine the influence of this localization on the mechanics of the system and hope to contribute to determining a possible adhesion to the cell wall.