Nernst-Planck-Gaussian finite element modelling of Ca electrodiffusion in amphibian striated muscle transverse tubule-sarcoplasmic reticular triadic junctional domains.

Introduction: Intracellular Ca signalling regulates membrane permeabilities, enzyme activity, and gene transcription amongst other functions. Large transmembrane Ca electrochemical gradients and low diffusibility between cell compartments potentially generate short-lived, localised, high-[Ca] microdomains. The highest concentration domains likely form between closely apposed membranes, as at amphibian skeletal muscle transverse tubule-sarcoplasmic reticular (T-SR, triad) junctions.

Controlling a new plasma regime.

Success of the UK's Spherical Tokamak for Energy Production (STEP) programme requires a robust plasma control system. This system has to guide the plasma from initiation to the burning phase, maintain it there, produce the desired fusion power for the desired duration and then terminate the plasma safely. This has to be done in a challenging environment with limited sensors and without overloading plasma-facing components.

Nernst-Planck-Gaussian modelling of electrodiffusional recovery from ephaptic excitation between mammalian cardiomyocytes.

In addition to gap junction conduction, recent reports implicate possible ephaptic coupling contributions to action potential (AP) propagation between successive adjacent cardiomyocytes. Here, AP generation in an active cell, withdraws Na from, creating a negative potential within, ephaptic spaces between the participating membranes, the initially quiescent neighbouring cardiomyocyte. However, sustainable ephaptic transmission requires subsequent complete of the ephaptic charge difference.

Finite element analysis predicts Ca microdomains within tubular-sarcoplasmic reticular junctions of amphibian skeletal muscle.

A finite element analysis modelled diffusional generation of steady-state Ca microdomains within skeletal muscle transverse (T)-tubular-sarcoplasmic reticular (SR) junctions, sites of ryanodine receptor (RyR)-mediated SR Ca release. It used established quantifications of sarcomere and T-SR anatomy (radial diameter [Formula: see text]; axial distance [Formula: see text]). Its boundary SR Ca influx densities,[Formula: see text], reflected step impositions of influxes, [Formula: see text] deduced from previously measured Ca signals following muscle fibre depolarization.

Could hydrodynamic Rossby waves explain the westward drift?

A novel theory for the origin of the westward drift of the Earth's magnetic field is proposed, based upon the propagation of hydrodynamic Rossby waves in the liquid outer core. These waves have the obscure property that their crests always progress eastwards-but, for a certain subset, energy can nevertheless be transmitted westwards. In fact, this subset corresponds to sheet-like flow structures, extended in both the axial and radial directions, which are likely to be preferentially excited by convective upwellings in the Earth's rapidly rotating outer core.