Lunch Seminar: Softmatter and Biophysics (Prof. Erwin Frey, Prof. Joachim Rädler)
This seminar takes place in collaboration with the Soft Condensed Matter Group of Prof. Rädler
Time and location
- The seminar takes place Tuesday at 12:00 in room 349 (Theresienstrasse).
Summer term 2007:
|10.7.2007||Peter Keim||Universität Konstanz||Phase transitions in a 2d colloidal system: Orientational stiffness in the hexatic phase|
|3.7.2007||Iva Tolic-Norrelykke||MPI of Molecular Cell Biology and Genetics||t.b.a.|
|26.6.2007||Claus Heussinger||LS Frey||Of fibers and grains: jamming vs. percolation|
|19.6.2007||Markus Rauscher||MPI fuer Metallforschung||Dynamics of thin liquid films: slip, viscoelasticity, and thermal fluctuations|
|6.6.2007||Andrea C. Jimenez Dalmaroni||MPI for Physics of Complex Systems||Physical description of mitotic spindle orientation during cell division|
|5.6.2007||Peter Krawitz||Klinikum rechts der Isar, Nuklearmedizinische Klinik der TU||Biological Boolean Models|
|29.5.2007||Christina Marchetti||Syracuse University||Hydrodynamic and rheology of soft active matter|
|15.5.2007||Alexander Skupin||Hahn-Meitner-Institut Berlin||Order from disorder: how calcium oscillates|
|8.5.2007||Simon Youssef||LS Rädler||Stochastic Simulations of the Gene Transfer|
Abstracts of passed seminars
- Peter Keim: Phase transitions in a 2d colloidal system: Orientational stiffness in the hexatic phase
- Abstract for download: [pdf]
- Additional material: [Publications P. Keim]
- Markus Rauscher: "Dynamics of thin liquid films: slip, viscoelasticity, and thermal fluctuations"
- Abstract: We study the dewetting dynamics of thin liquid films. In particular, we use a mesoscopic approach, augmenting macroscopic hydrodynamic equations by taking into account hydrodynamic slip, the substrate potential (van der Waals forces), and thermal fluctuations. After a brief introduction in the topic of dewetting of non-volative fluid films, we discuss the role of thermal fluctuations in spinodal dewetting and show clear experimental evidence for them. The second part of the talk is dedicated to the interplay of slip and viscoelasticity in dewetting films and the resulting dewetting patterns. In particular we show that the shape of the rim around holes in dewetting films is mostly determined by slip and not by viscoelasticity. In addition, we use the shape analysis to measure the slip length.
- Additional material I: Slip-controlled thin film dynamics, R. Fetzer, M. Rauscher, A. Muench, B. A. Wagner, and K. Jacobs, Europhysics Letters 75(4), 638-644 (2006) cond-mat/0603452 [Article]
- Additional materials II:A thin film model for corotational Jeffreys fluids under strong slip, A. Muench, B. Wagner, M. Rauscher, and R. Blossey, Eur. Phys. J. E 20(4), 365-368 (2006) [Article]
- Andrea Jimenez: "Physical description of mitotic spindle orientation during cell division"
- Abstract:During cell division, the duplicated chromosomes are physically separated by the action of the mitotic spindle. The mitotic spindle is a dynamic structure of the cytoskeleton, which consists of two microtubule asters. Its orientation defines the axis along which the cell divides. Recent experiments on dividing cells, which adhere to patterned substrates, show that the spindle orientation depends on the spatial distribution of cell adhesion sites. In this talk I will show that the experimentally observed spindle orientation can be understood as the result of the action of cortical force generators acting on the spindle microtubules. We develop a simple physical description of the spindle mechanics based on the assumption that the local activity of force generators is controlled by the spatial distribution of cell adhesion sites. We calculate the torque acting on the spindle, as well as the energy profile and the angular distribution of spindle orientation. Our model accounts for the preferred spindle orientation, as well as the full shape of the angular distributions of spindle orientation observed in a wide variety of pattern geometries.
- Additional material: Experimental and theoretical study of mitotic spindle orientation
- Peter Krawitz: "Biological Boolean Networks"
- Abstract: Boolean Networks (BN) are a class of discrete dynamical systems that can be characterized by the interaction of a set of Boolean variables. BN have been used as generic models for dynamics of complex systems of interacting entities, such as social and economic networks, neural networks, gene and protein interaction networks. Despite their conceptual simplicity BN exhibit complex nonlinear behaviour that are, to this day, a challenging object of investigation. After a short introduction and historical overview we will more thoroughly discuss the newly introduced network parameter "basin entropy" and its scaling behavior in different ensembles of random BNs.
- Additional material: Basin Entropy in Boolean Network Ensembles