FULL-FIELD ELASTIC SIMULATIONS FOR IMAGE-BASED HETEROGENEOUS STRUCTURES WITH A COARSE MESH CONDENSATION MULTISCALE METHOD

Conventional finite-difference frequency-domain (FDFD) methods can describe wave attenuation and velocity dispersion more easily than time-domain methods. However, there are significant challenges associated with computational costs for solving the linear system when frequency-domain methods are applied in models with large dimensions or fine-scale property variations. Direct-iterative solvers and parallel strategies attempt a tradeoff between memory and time costs. We follow the general framework of heterogeneous multiscale method and develop a multiscale FDFD approach to solve the Helmholtz equation with lower memory and time costs. To achieve this, the discrete linear system approximating the Helmholtz equation is constructed on a coarse mesh, making its dimension much smaller than that of conventional methods. The coefficient matrix in the linear system of dimension-reduction captures fine-scale heterogeneity in the media by coupling fine- and coarse-scale meshes. Several test models are used to verify the accuracy of our multiscale method and investigate potential sources of error. Numerical results demonstrate that our method accurately approximates the wavefields of fine-scale solutions at low frequencies of the source, and could produce solutions with small errors by reducing the size of the coarse mesh cells at high frequencies as well. Comparisons of computational costs with conventional FDFD methods show that the proposed multiscale method significantly reduces computation time and memory consumption.

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Membrane–cytoskeleton interactions in cholesterol-dependent domain formation

Essays in Biochemistry ◽

10.1042/bse0570177 ◽

2015 ◽

Vol 57 ◽

pp. 177-187 ◽

Cited By ~ 9

Author(s):

Jennifer N. Byrum ◽

William Rodgers

Keyword(s):

Biological Properties ◽

Membrane Rafts ◽

Membrane Domains ◽

Biological Functions ◽

Membrane Cytoskeleton ◽

Heterogeneous Structures ◽

Integral Role ◽

Model Cell ◽

Actomyosin Cytoskeleton ◽

Dependent Domain

Since the inception of the fluid mosaic model, cell membranes have come to be recognized as heterogeneous structures composed of discrete protein and lipid domains of various dimensions and biological functions. The structural and biological properties of membrane domains are represented by CDM (cholesterol-dependent membrane) domains, frequently referred to as membrane ‘rafts’. Biological functions attributed to CDMs include signal transduction. In T-cells, CDMs function in the regulation of the Src family kinase Lck (p56lck) by sequestering Lck from its activator CD45. Despite evidence of discrete CDM domains with specific functions, the mechanism by which they form and are maintained within a fluid and dynamic lipid bilayer is not completely understood. In the present chapter, we discuss recent advances showing that the actomyosin cytoskeleton has an integral role in the formation of CDM domains. Using Lck as a model, we also discuss recent findings regarding cytoskeleton-dependent CDM domain functions in protein regulation.

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