Author: Laura Mary Miller
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Author: Triantafyllos Stylianopoulos
Publisher:
ISBN:
Category :
Languages : en
Pages : 456

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Author: Adam Michael Reeve
Publisher:
ISBN:
Category : Body fluid flow
Languages : en
Pages : 201

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Biological tissues consist of a mixture of fluid and solid components, and the mechanical behaviour of a tissue can be influenced by the fluid within that tissue. This thesis investigated how fluid pressure affects tissue mechanics, and how this influence can be incorporated in continuum-level models of whole organs. Firstly, a physical phantom model of vascularised tissue was constructed using silicone gel. Mechanical experiments were performed on this phantom to determine how it responded to changes in fluid pressure. Replicating the nonlinear, strain-stiffening behaviour of some tissues was attempted by incorporating a strain stiffening wool-yarn into the gel. Following this, a representative volume element model of vascularised tissue was developed that explicitly modelled vessels within tissue. This model predicted that anisotropy in the constitutive behaviour of a tissue's solid components causes anisotropic swelling and stiffening, and that anisotropic vascular structure also contributes to anisotropic swelling. It was demonstrated that poroelasticity can be used to model increases in stiffness with fluid pressure, provided that the poroelastic material's constitutive relation is strain-stiffening, and the strain-stiffening terms are volume dependent. Approaches for incorporating anisotropic vascular structure in poroelastic models were then investigated and compared. A poroelastic model with anisotropic constitutive behaviour was used to model the effect of perfusion pressure on the passive mechanics of the left ventricle of the heart. This model could reproduce the swelling deformation of myocardium, but further development of constitutive relations is required to accurately reproduce anisotropy in stiffness changes. Finally, the effect of perfusion pressure on the mechanics of the rat tibialis anterior muscle was investigated. No significant change in muscle stiffness was observed between perfusion pressures of 5 kPa and 20 kPa, but a small swelling deformation was measured.

Author: Judy Ping Yang
Publisher:
ISBN:
Category :
Languages : en
Pages : 206

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Biot's theory has been widely used to construct the poroelasticity models for describing the mechanical behavior of biological materials. This phenomenological framework, however, does not take the explicit microstructural configuration and the corresponding solid-fluid coupling into consideration. This work investigates how the microstructural configuration and material properties of porous materials constitute the macroscopic poroelastic material behavior described by the classical Biot's theory. We introduced an asymptotic based homogenization method to correlate the macro- and micro-mechanical behaviors of poroelastic materials, where an elastic solid and Newtonian fluid of low viscosity are considered. Through this homogenization process, the generalized Darcy's law, homogenized macroscopic continuity equation, and homogenized macroscopic equilibrium equation were obtained, where the homogenized macroscopic continuity and equilibrium equations reassemble the governing equations in Biot's theory. For an effective modeling of microstructures, a numerical solution for PDEs based on a strong form collocation that employs image pixels as the discretization points is proposed. To achieve this objective, a gradient reproducing kernel collocation method (G-RKCM) formulated based on the partition of nullity and gradient reproducing conditions was developed. This approach reduces the order of differentiation to the first order when solving second order PDEs with strong form collocation. We showed that the same number of collocation points and source points can be used in G-RKCM for optimal convergence, unlike other strong form collocation methods. In addition, same order of convergence rate in the solution and its first order derivative are achieved, owing to the imposition of gradient reproducing conditions. The computational complexity of G-RKCM is also shown to be an enhancement over other strong form collocation methods, such as the reproducing kernel collocation method (RKCM). In this work, we introduced the active contour model based on variational level set formulation for interface identification and boundary segmentation for the discretization of microstructures based on medical images. Using pixel point discretization, we introduced the RKCM and G-RKCM to solve the level set equation. In particular, the G-RKCM has been shown be effective since the second derivatives of the level set function involved in the regularization term are approximated by the first order differentiations of the gradient RK shape functions. We further showed that a B-spline kernel function with lower continuity can be preferably used to avoid the oscillation of level set functions in the two-color images. The image based G-RKCM was applied to model trabecular bone microstructures with complex geometry for both solid and fluid phases. The corresponding numerical issues such as interface discretization and kernel function support size selection have been addressed. The investigation on the proper choice of unit cell dimension and image resolution has been performed, which provides guidance in the image-based trabecular bone modeling. The validation of the proposed image based multiscale modeling framework has been carried out by comparing the numerical prediction of effective material properties with experimental data of trabecular bone in the literature and solving a macroscopic trabecular bone problem using the homogenized material constants.

Author: Paulo R. Fernandes
Publisher: Springer Science & Business Media
ISBN: 9400712545
Category : Computers
Languages : en
Pages : 181

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This book presents a collection of chapters describing the state of the art on computational modelling and fabrication in tissue engineering. Tissue Engineering is a multidisciplinary field involving scientists from different fields. The development of mathematical methods is quite relevant to understand cell biology and human tissues as well to model, design and fabricate optimized and smart scaffolds. The chapter authors are the distinguished keynote speakers at the first Eccomas thematic conference on Tissue Engineering where the emphasis was on mathematical and computational modeling for scaffold design and fabrication. This particular area of tissue engineering, whose goal is to obtain substitutes for hard tissues such as bone and cartilage, is growing in importance.

Author: Socrates Dokos
Publisher: Springer
ISBN: 3642548016
Category : Technology & Engineering
Languages : en
Pages : 504

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This book presents a theoretical and practical overview of computational modeling in bioengineering, focusing on a range of applications including electrical stimulation of neural and cardiac tissue, implantable drug delivery, cancer therapy, biomechanics, cardiovascular dynamics, as well as fluid-structure interaction for modelling of organs, tissues, cells and devices. It covers the basic principles of modeling and simulation with ordinary and partial differential equations using MATLAB and COMSOL Multiphysics numerical software. The target audience primarily comprises postgraduate students and researchers, but the book may also be beneficial for practitioners in the medical device industry.

Author: Jerome Noailly
Publisher: Frontiers Media SA
ISBN: 2889746623
Category : Science
Languages : en
Pages : 317

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Author: Boo Cheong Khoo
Publisher: World Scientific
ISBN: 981283785X
Category : Mathematics
Languages : en
Pages : 184

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This volume showcases lecture notes collected from tutorials presented at the Workshop on Moving Interface Problems and Applications in Fluid Dynamics that was held between January 8 and March 31, 2007 at the Institute for Mathematical Sciences, National University of Singapore. As part of the program, these tutorials were conducted by specialists within their respective areas such as Robert Dillon, Zhilin Li, John Lowengrub, Frank Lu and Gretar Tryggvason. The topics in the program encompass modeling and simulations of biological flow coupled to deformable tissue/elastic structure, shock wave and bubble dynamics and various applications like biological treatments with experimental verification, multi-medium flow or multiphase flow and various applications including cavitation/supercavitation, detonation problems, Newtonian and non-Newtonian fluid, and many other areas. This volume benefits graduate students and researchers keen in the field of interfacial flows for application to physical and biological systems. Even beginners will find this volume a very useful starting point with many relevant references applicable.

Author: Alphose Zingoni
Publisher: CRC Press
ISBN: 0429761171
Category : Technology & Engineering
Languages : en
Pages : 882

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Book Description
Advances in Engineering Materials, Structures and Systems: Innovations, Mechanics and Applications comprises 411 papers that were presented at SEMC 2019, the Seventh International Conference on Structural Engineering, Mechanics and Computation, held in Cape Town, South Africa, from 2 to 4 September 2019. The subject matter reflects the broad scope of SEMC conferences, and covers a wide variety of engineering materials (both traditional and innovative) and many types of structures. The many topics featured in these Proceedings can be classified into six broad categories that deal with: (i) the mechanics of materials and fluids (elasticity, plasticity, flow through porous media, fluid dynamics, fracture, fatigue, damage, delamination, corrosion, bond, creep, shrinkage, etc); (ii) the mechanics of structures and systems (structural dynamics, vibration, seismic response, soil-structure interaction, fluid-structure interaction, response to blast and impact, response to fire, structural stability, buckling, collapse behaviour); (iii) the numerical modelling and experimental testing of materials and structures (numerical methods, simulation techniques, multi-scale modelling, computational modelling, laboratory testing, field testing, experimental measurements); (iv) innovations and special structures (nanostructures, adaptive structures, smart structures, composite structures, bio-inspired structures, shell structures, membranes, space structures, lightweight structures, long-span structures, tall buildings, wind turbines, etc); (v) design in traditional engineering materials (steel, concrete, steel-concrete composite, aluminium, masonry, timber, glass); (vi) the process of structural engineering (conceptualisation, planning, analysis, design, optimization, construction, assembly, manufacture, testing, maintenance, monitoring, assessment, repair, strengthening, retrofitting, decommissioning). The SEMC 2019 Proceedings will be of interest to civil, structural, mechanical, marine and aerospace engineers. Researchers, developers, practitioners and academics in these disciplines will find them useful. Two versions of the papers are available. Short versions, intended to be concise but self-contained summaries of the full papers, are in this printed book. The full versions of the papers are in the e-book.

Author: Katarzyna A. Rejniak
Publisher: Springer
ISBN: 3319420232
Category : Medical
Languages : en
Pages : 264

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Book Description
This edited volume discusses the complexity of tumor microenvironments during cancer development, progression and treatment. Each chapter presents a different mathematical model designed to investigate the interactions between tumor cells and the surrounding stroma and stromal cells. The topics covered in this book include the quantitative image analysis of a tumor microenvironment, the microenvironmental barriers in oxygen and drug delivery to tumors, the development of tumor microenvironmental niches and sanctuaries, intravenous transport of the circulating tumor cells, the role of the tumor microenvironment in chemotherapeutic interventions, the interactions between tumor cells, the extracellular matrix, the interstitial fluid, and the immune and stromal cells. Mathematical models discussed here embrace both continuous and agent-based approaches, as well as mathematical frameworks of solid mechanics, fluid dynamics and optimal control theory. The topics in each chapter will be of interest to a biological community wishing to apply the mathematical methods to interpret their experimental data, and to a biomathematical audience interested in exploring how mathematical models can be used to address complex questions in cancer biology.