E. Pirozzi | Searcharxiv

arXiv2005

On Myosin II dynamics in the presence of external loads

We address the controversial hot question concerning the validity of the loose coupling versus the lever-arm theories in the actomyosin dynamics by re-interpreting and extending the phenomenological washboard potential model proposed by some of us in a previous paper. In this new model a Brownian motion harnessing thermal energy is assumed to co-exist with the deterministic swing of the lever-arm, to yield an excellent fit of the set of data obtained by some of us on the sliding of Myosin II heads on immobilized actin filaments under various load conditions. Our theoretical arguments are complemented by accurate numerical simulations, and the robustness of the model is tested via different choices of parameters and potential profiles.

q-bio.SC↗

arXiv2004

A Phenomenological model of Myosin II dynamics in the presence of external loads

We address the controversial hot question concerning the validity of the loose coupling versus the lever-arm theories in the actomyosin dynamics by re-interpreting and extending the phenomenological washboard potential model proposed by some of us in a previous paper. In this new model a Brownian motion harnessing thermal energy is assumed to co-exist with the deterministic swing of the lever-arm, to yield an excellent fit of the set of data obtained by some of us on the sliding of Myosin II heads on immobilized actin filaments under various load conditions. Our theoretical arguments are complemented by accurate numerical simulations, and the robustness of the model is tested via different choices of parameters and potential profiles.

q-bio.BM↗

arXiv2004

Lever-arm and Washboard-potential theories jointly account for Myosin II dynamics

We address the controversial hot question concerning the validity of the loose-coupling versus the lever-arm models in the actomyosin dynamics by re-interpreting and extending the washboard potential model proposed by some of us in a previous paper. In the new theory, a loose-coupling mechanism co-exists with the deterministic lever-arm model. The synergetic action of a random component, originating from the harnessed thermal energy, and of the power-stroke generated by the lever-arm classical mechanism is seen to yield an excellent fit of the set of data obtained in T. Yanagida's laboratory on the sliding of Myosin II heads on actin filaments under various load conditions. Our theoretical arguments are complemented by accurate numerical simulations, and the robustness of theory is tested via different combination of parameters and potential profiles.

q-bio.BM↗

arXiv2003

On the asymptotic behavior of first passage time densities for stationary Gaussian processes

Making use of a Rice-like series expansion, for a class of stationary Gaussian processes the asymptotic behavior of the first passage time probability density function through certain time-varying boundaries, including periodic boundaries, is determined. Sufficient conditions are then given such that the density asymptotically exhibits an exponential behavior when the boundary is either asymptotically constant or asymptotically periodic.

math.PR↗

arXiv2003

Towards the Modeling of Neuronal Firing by Gaussian Processes

This paper focuses on the outline of some computational methods for the approximate solution of the integral equations for the neuronal firing probability density and an algorithm for the generation of sample-paths in order to construct histograms estimating the firing densities. Our results originate from the study of non-Markov stationary Gaussian neuronal models with the aim to determine the neuron's firing probability density function. A parallel algorithm has been implemented in order to simulate large numbers of sample paths of Gaussian processes characterized by damped oscillatory covariances in the presence of time dependent boundaries. The analysis based on the simulation procedure provides an alternative research tool when closed-form results or analytic evaluation of the neuronal firing densities are not available.

math.PR↗