Biomedical subjects

Erwin Frey

Publications and source records attributed to Erwin Frey.

24 records · Page 2Linked to original sources

PubMed2004

Novel universality classes of coupled driven diffusive systems.

Motivated by the phenomenologies of dynamic roughening of strings in random media and magnetohydrodynamics, we examine the universal properties of driven diffusive system with coupled fields. We demonstrate that cross correlations between the fields lead to amplitude ratios and scaling exponents varying continuously with the strength of these cross correlations. The implications of these results for experimentally relevant systems are discussed.

Journal Article↗

PubMed2004

Collective phenomena in intracellular processes.

Intracellular transport and cytoskeletal organization are the result of an interaction between elastic filaments and force generation by motor proteins. The observed phenomena are still too complex for a complete theoretical description. Studies on simple model systems reveal interesting collective phenomena which can be understood on the basis of driven stochastic processes far from equilibrium.

Animals↗

PubMed2003

Elasticity of stiff polymer networks.

We study the elasticity of a two-dimensional random network of rigid rods ("Mikado model"). The essential features incorporated into the model are the anisotropic elasticity of the rods and the random geometry of the network. We show that there are three distinct scaling regimes, characterized by two distinct length scales on the elastic backbone. In addition to a critical rigidity percolation region and a homogeneously elastic regime we find a novel intermediate scaling regime, where the elasticity is dominated by bending deformations.

Biopolymers↗

PubMed2002

Tracer studies on f-actin fluctuations.

We present a study on the fluctuations of semiflexible actin filaments using fluorescence videomicroscopy, focusing on the end-to-end fluctuations of single filaments. In order to specifically measure the position of the polymer's ends, we developed a novel noninvasive method that consists of annealing short end tags to the filaments. This allows us to probe polymer fluctuations to a very high accuracy. We compared the distribution of the end-to-end distance with recent theoretical results, and found excellent agreement. We also studied the dynamics of the mean-square end-to-end distance deltaR2(t) and orientation of the ends, deltaTheta(2)(t), finding power laws t(3/4) and t(1/4), respectively. Scaling behavior for deltaR2(t) is observed over several decades in relaxation time in agreement with theoretical results.

Actins↗

PubMed2002

Physics in cell biology: on the physics of biopolymers and molecular motors.

"What is Life?" is the title of a book by Erwin Schrödinger, first published in 1944. This book is a bold attempt to try to understand some of the wonders of life in terms of physics, in particular statistical mechanics. Since the publication of this visionary book, we have seen a revolution in molecular biology complemented by the development of new physical tools like single-molecule spectroscopy. The goal of this article is to highlight some examples where physics can contribute to questions in cell biology. One might hope that through interdisciplinary research one can get closer to answering Schrödinger's fundamental question.

Biophysical Phenomena↗

PubMed2002

Domain wall roughening in dipolar films in the presence of disorder.

We derive a low-energy Hamiltonian for the elastic energy of a Néel domain wall in a thin film with in-plane magnetization, where we consider the contribution of the long-range dipolar interaction beyond the quadratic approximation. We show that such a Hamiltonian is analogous to the Hamiltonian of a one-dimensional polaron in an external random potential. We use a replica variational method to compute the roughening exponent of the domain wall for the case of two-dimensional dipolar interactions.

Journal Article↗