Eckart Frehland

Learn More
Subject of this paper is the transport noise in discrete systems. The transport systems are given by a number (n) of binding sites separated by energy barriers. These binding sites may be in contact outer reservoirs. The state of the systems is characterized by the occupation numbers of particles (current carriers) at these binding sites. The change in time(More)
A general theoretical approach to the analysis of electric fluctuations generated by the so-called single-file diffusion through narrow channels is presented. The formalism is a slight extension of an approach to electric fluctuations in discrete transport systems with negligible interactions between the particles recently developed by one of the authors.(More)
In rate-theory analysis of ion transport in channels, the energy of binding sites and the height of activation barriers are usually considered to be time-independent and not influenced by the movement of the ion. The assumption of a fixed barrier structure seems questionable, however, in view of the fact that proteins may exist in a large number of(More)
A quantitative fluorescence polarization theory of molecules bound to two-dimensional plane layers has been developed when the electronic transition moments of absorption and emission are parallel within the fluorescent molecules. The transition moments are assumed to be in preferred orientation with respect to the normal to the plane and to be randomly(More)
A recently developed theoretical approach to transport fluctuations around stable steady states in discrete biological transport systems is used in order to investigate general fluctuation properties at nonequilibrium. An expression for the complex frequency dependent admittance at nonequilibrium is derived by calculation of the linear current response of(More)
Apical sodium-selective channels in frog skin, when blocked by amiloride or triamterene, exhibit fluctuations in current, the spectra of which are Lorentzian. These effects have been modeled previously with two-state and three-state models by Lindemann and Van Driessche. A recent observation by Hoshiko and Van Driessche that corner frequencies are lowered(More)
A theoretical approach to transport noise in kinetic systems, which has recently been developed, is applied to electric fluctuations around steady-states in membrane channels with different conductance states. The channel kinetics may be simple two state (open-closed) kinetics or more complicated. The membrane channel is considered as a sequence of binding(More)
The measured spectral intensity Sj(f) of noise-current generated by carrier-mediated ion transport on bilayer membranes agrees under equilibrium and nonequilibrium conditions with the theoretically predicted behavior. It is shown that the shot noise intensity due to this ion transport mechanism yields a frequency independent level of Sj(f) at higher(More)
A theory is developed appropriate for the analysis of fluorescence polarization experiments with pigment molecules in a planar array (plane membrane). Especially rotatory and oscillatory dynamics of the pigment molecules are considered. Three model calculations are performed, which describe the following different situations: (a) Rotational diffusion of(More)