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Numerical results for dielectric and electrokinetic properties of vesicle in a broad frequency range extending from 1 Hz to 1 GHz are presented. The results show important qualitative differences with respect to suspensions of charged homogenous particles, which are mainly due to the existence of an additional dispersion mechanism, charging of the membrane.

The electrorotation velocity of spherical colloidal polystyrene particles suspended in an electrolyte solution is calculated with the help of a network simulation method. The findings are in good agreement with the existing theoretical results when applicable, and they extend to ranges where these theories cannot be applied.

Dielectric spectra of a suspension of cells in electrolyte solution and dipole coefficient spectra induced by an AC electric field are numerically calculated using a network simulation method. The dependence of the low-frequency dielectric spectra with the internal medium properties is analyzed.

A numerical method is used to solve the electric potential ion number concentration, and fluid velocity distributions induced by an ac electric field applied to a cell suspended in an electrolyte solution is presented. Here, the dependence of the rotation spectra cells with some of the parameters is considered.

The development of biophysical models of the heart has the potential to get insights in the patho-physiology of the heart, which requires to accurately modeling anatomy and function. The electrical activation sequence of the ventricles depends strongly on the cardiac conduction system (CCS). Its morphology and function cannot be observed in vivo, and therefore data available come from histological studies. We present a review on data available of the peripheral CCS including new experiments. In order to build a realistic model of the CCS we designed a procedure to extract morphological characteristics of the CCS from stained calf tissue samples. A CCS model personalized with our measurements has been built using L-systems. The effect of key unknown parameters of the model in the electrical activation of the left ventricle has been analyzed. The CCS models generated share the main characteristics of observed stained Purkinje networks. The timing of the simulated electrical activation sequences were in the physiological range for CCS models that included enough density of PMJs. These results show that this approach is a potential methodology for collecting knowledge-domain data and build improved CCS models of the heart automatically. [ABSTRACT FROM PUBLISHER]

A methodology is presented here for automatic construction of a ventricular model of the cardiac conduction system (CCS), which is currently a missing block in many multiscale cardiac electromechanic models. It includes the His bundle, left bundle branches, and the peripheral CCS. The algorithm is fundamentally an enhancement of a rule-based method known as the Lindenmayer systems (L-systems). The generative procedure has been divided into three consecutive independent stages, which subsequently build the CCS from proximal to distal sections. Each stage is governed by a set of user parameters together with anatomical and physiological constrains to direct the generation process and adhere to the structural observations derived from histology studies. Several parameters are defined using statistical distributions to introduce stochastic variability in the models. The CCS built with this approach can generate electrical activation sequences with physiological characteristics. [ABSTRACT FROM AUTHOR]

We present a method to automatically deploy the peripheral section of the cardiac conduction system in ventricles. The method encodes anatomical information thorough rules that ensure that Purkinje network structures generated are realistic and comparable to those observed in ex-vivo studies. The core methodology is based in non-deterministic production rules that are parameterized by means of statistical functions. Input parameters allow the construction of a great diversity of Purkinje structures that could be incorporated in fine element ventricular models to perform electrophysiology simulations. Resulting Purkinje trees show good geometrical approximations of Purkinje core network and bundles when compared to histological diagrams and do not require user interaction. Simulations carried out with these models result in activation sequences remarkably similar to micro-electrode electrical mapping studies.