Wave-driven phase wave patterns in a ring of FitzHugh-Nagumo oscillators.

We explore a biomimetic model that simulates a cell, with the internal cytoplasm represented by a two-dimensional circular domain and the external cortex by a surrounding ring, both modeled using FitzHugh-Nagumo systems. The external ring is dynamically influenced by a pacemaker-driven wave originating from the internal domain, leading to the emergence of three distinct dynamical states based on the varying strengths of coupling. The range of dynamics observed includes phase patterning, the propagation of phase waves, and interactions between traveling and phase waves.

Puncture dilatation tracheostomy in children during transoral neurosurgical interventions.

Unlabelled: Neurosurgical interventions within the ventral surface of the clivus and upper cervical vertebrae in childhood are sometimes carried out through transoral approach. In this situation, tracheostomy is safer for airway protection and mechanical ventilation compared to prolonged intubation. The world experience of percutaneous dilation tracheostomy in pediatric patients is limited due to anatomical and physiological features, such as difficult orientation in anatomical landmarks, high mobility of the trachea and small tracheal lumen.

Actomyosin cortex: Inherently oscillatory?

A new analysis of cytokinetic furrow ingression in the Caenorhabditis elegans zygote at high spatiotemporal resolution demonstrates that, rather than being a process of steady, spatially uniform constriction, furrow ingression is modulated by complex contractile oscillations that move around the furrow, possibly in the form of propagating waves.

Testing models of cell cortex wave generation by Rho GTPases.

The Rho GTPases pattern the cell cortex in a variety of fundamental cell-morphogenetic processes including division, wound repair, and locomotion. It has recently become apparent that this patterning arises from the ability of the Rho GTPases to self-organize into static and migrating spots, contractile pulses, and propagating waves in cells from yeasts to mammals . These self-organizing Rho GTPase patterns have been explained by a variety of theoretical models which require multiple interacting positive and negative feedback loops.