Forces between charged macromolecules are strongly affected by the intervening ionic solution. In most theoretical works the solution is treated as a homogeneous structureless dielectric medium but recent experiments show that for a solution composed of two solvents, the osmotic pressure between macromolecules depends on solvent composition. By adding local solvent composition terms to the free energy, we obtain the mean-field osmotic pressure in planar geometry. The added effect is due to inhomogeneous permeability and nonelectrostatic short-range interactions between ions and solvent.
COBISS.SI-ID: 2159972
We report experiments that probe self-assembly of micrometer-size colloids into one-particle-thick and robust membranes. In magic-angle precessing magnetic field, superparamagnetic spheres experience isotropic pair attraction similar to the van der Waals force between atoms. But the many-body polarization interactions among them steer an ordered aggregation pathway consisting of growth of short chains, cross-linking and network formation, network coarsening, and consolidation of membrane patches. This generic aggregation scenario can be induced in any particles of large enough susceptibility.
COBISS.SI-ID: 2204516
We developed a theoretical model of mechanics of a monolayered epithelium. The model connects the macroscopic mechanical properties of monolayered epithelium to the mechanical properties at the cellular level. The equilibrium state of the epithelium and its macroscopic elastic moduli were calculated. The analysis indicates that the epithelial mechanical behavior is defined primarily by the ratio between the intercellular adhesion strength and the cellular cortical tension.
COBISS.SI-ID: 25930201
We studied typical experimental traces of Ca2+ responses in pancreatic acinar cells stimulated by the physiological agonist acetylcholine. By performing surrogate data tests and employing a determinism test for short time series, we show that the responses are stochastic with only faintly expressed deterministic features. The reported results thus corroborate the notion that mathematical models should take stochasticity explicitly into account when describing intra- and intercellular processes of signal transduction in pancreatic acinar cells.
COBISS.SI-ID: 13698582
We found that different contributions to the resistivity in pentacene-based organic thin ?lm transistors exhibit different time dependences upon exposure to ambient air. Kelvin force microscopy data show that contact resistance at the drain/source interface and the resistance of the pentacene channel initially decrease and after 6 h increase monotonically. The resistance at the source/pentacene interface initially decreases and exhibits a small increase after 6 h. This effect is explained by a competition of oxygen and water penetration in the pentacene channel and in the interfacial region.
COBISS.SI-ID: 1075451