Subject-specific, multiscale simulation of electrophysiology: a software pipeline for image-based models and application examples

Many simulation studies in biomedicine are based on a similar sequence of processing steps, starting from images and running through geometric model generation, assignment of tissue properties, numerical simulation and visualization of the results—a process known as image-based geometric modelling and simulation. We present an overview of software systems for implementing such a sequence both within highly integrated problem-solving environments and in the form of loosely integrated pipelines. Loose integration in this case indicates that individual programs function largely independently but communicate through files of a common format and support simple scripting, so as to automate multiple executions wherever possible. We then describe three specific applications of such pipelines to translational biomedical research in electrophysiology

Large Eddy Simulation of High Reynolds Number Jets with Microjet Injection

Large eddy simulations of two isothermal Mach 0.75 jets have been performed, one of a clean jet and one of the same jet fitted with eight equally spaced microjets. The microjets have a pressure ratio of 2.38, with a fully expanded Mach number of 1.19. The Reynolds number of the main jet in both simulations, based on the jet core velocity and diameter, is 1.3 million. The simulations were performed on a cylindrical, structured, multiblock mesh created for the clean round jet. The microjets are introduced as pressure inlet areas within the computational domain, so avoiding the complication of modelling the microjet feed pipes. Results of the clean jet simulation agree well with experimental data. The simulation shows the microjets penetrating into the jet core and disrupting the otherwise circular nature of the shear layer in the early flow development regions, though no change in mean flow variables is noticed by the end of the potential core. Two-point two-time correlation are performed on both cases and compared. The results show the microjets reduce the second and fourth order correlation amplitudes and turbulent lengthscales even at large axial locations downstream of the nozzle exit, where the effect of the microjets on the mean flow field is not present. This gives evidence as to how the microjets are able to reduce jet noise levels

In vivo assessment of iron content of the cerebral cortex in healthy aging using 7-Tesla T2*-weighted phase imaging

Neuro Imaging Researc