E. Alvarez-Lacalle

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We present a model for the actin contractile ring of adherent animal cells. The model suggests that the actin concentration within the ring and consequently the power that the ring exerts both increase during contraction. We demonstrate the crucial role of actin polymerization and depolymerization throughout cytokinesis, and the dominance of viscous(More)
We analyze the characteristics of front propagation in activity of 1-D neuronal cultures by numerical simulations, using only excitatory dynamics. Experimental results in 1-D cultures of hippocampal neurons from rats have shown the spontaneous generation of a slow, low amplitude pulse that precedes a high amplitude, fast pulse that propagates through all(More)
A variety of cardiac arrhythmias are initiated by a focal excitation that disrupts the regular beating of the heart. In some cases it is known that these excitations are due to calcium (Ca) release from the sarcoplasmic reticulum (SR) via propagating subcellular Ca waves. However, it is not understood what are the physiological factors that determine the(More)
BACKGROUND Rapid pacing rates induce alternations in the cytosolic calcium concentration caused by fluctuations in calcium released from the sarcoplasmic reticulum (SR). However, the relationship between calcium alternans and refractoriness of the SR calcium release channel (RyR2) remains elusive. METHODOLOGY/PRINCIPAL FINDINGS To investigate how(More)
Spontaneous calcium release (SCR) occurs when ion channel fluctuations lead to the nucleation of calcium waves in cardiac cells. This phenomenon is important since it has been implicated as a cause of various cardiac arrhythmias. However, to date, it is not understood what determines the timing and location of spontaneous calcium waves within cells. Here,(More)
When neurons are grown in vitro and left unperturbed, they create their own network of connections and eventually reach a state where they fire simultaneously in a strikingly regular collective pattern of nearly periodic bursts [1]. Even though the spontaneous activity of neuro-nal networks is widely recognized as a fundamental problem in neuroscience, the(More)
1 The mean first passage time for a single cluster When the spark activation for the cluster is dictated by the closed to open transitions, the stochastic dynamics of the cluster is governed by the master equation dP (n, t) dt = w + (n − 1)P (n − 1, t) + w − (n + 1)P (n + 1, t) − (w + (n) + w − (n)) P (n, t) (1) where P (n, t) is the probability for n(More)
The goal of this paper is to describe the effects of simple electro-mechanical coupling in isotropic two-dimensional (2D) cardiac tissue. To this aim, we show that the Nash-Panfilov two variable model [PRL 95, 258104 (2005)] for electrical activation, which couples active stress directly to transmembrane potential, can be reduced in the linearly elastic(More)
We show, both theoretically and experimentally, that the interface between two viscous fluids in a Hele-Shaw cell can be nonlinearly unstable before the Saffman-Taylor linear instability point is reached. We identify the family of exact elastica solutions [Nye et al., Eur. J. Phys. 5, 73 (1984)]] as the unstable branch of the corresponding subcritical(More)
We present a weakly nonlinear analysis of the interface dynamics in a radial Hele-Shaw cell driven by both injection and rotation. We extend the systematic expansion introduced in [E. Alvarez-Lacalle et al., Phys. Rev. E 64, 016302 (2001)] to the radial geometry, and compute explicitly the first nonlinear contributions. We also find the necessary and(More)
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