scholarly journals Multiple scale model for cell migration in monolayers: Elastic mismatch between cells enhances motility

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Benoit Palmieri ◽  
Yony Bresler ◽  
Denis Wirtz ◽  
Martin Grant
Keyword(s):  
Cell Migration ◽  
Multiple Scale ◽  
Scale Model ◽  
Elastic Mismatch

scholarly journals On-lattice agent-based simulation of populations of cells within the open-source Chaste framework

2013 ◽  
Vol 3 (2) ◽  
pp. 20120081 ◽  
Author(s):  
Grazziela P. Figueredo ◽  
Tanvi V. Joshi ◽  
James M. Osborne ◽  
Helen M. Byrne ◽  
Markus R. Owen
Keyword(s):  
Tumour Growth ◽  
Current System ◽  
Reaction Diffusion ◽  
Multiple Scale ◽  
Reaction Diffusion Equations ◽  
Scale Model ◽  
Low Oxygen ◽  
Model Framework ◽  
Agent Based ◽  
Multi Scale

Over the years, agent-based models have been developed that combine cell division and reinforced random walks of cells on a regular lattice, reaction–diffusion equations for nutrients and growth factors; and ordinary differential equations for the subcellular networks regulating the cell cycle. When linked to a vascular layer, this multiple scale model framework has been applied to tumour growth and therapy. Here, we report on the creation of an agent-based multi-scale environment amalgamating the characteristics of these models within a Virtual Physiological Human (VPH) Exemplar Project. This project enables reuse, integration, expansion and sharing of the model and relevant data. The agent-based and reaction–diffusion parts of the multi-scale model have been implemented and are available for download as part of the latest public release of Chaste (Cancer, Heart and Soft Tissue Environment; http://www.cs.ox.ac.uk/chaste/), part of the VPH Toolkit (http://toolkit.vph-noe.eu/). The environment functionalities are verified against the original models, in addition to extra validation of all aspects of the code. In this work, we present the details of the implementation of the agent-based environment, including the system description, the conceptual model, the development of the simulation model and the processes of verification and validation of the simulation results. We explore the potential use of the environment by presenting exemplar applications of the ‘what if’ scenarios that can easily be studied in the environment. These examples relate to tumour growth, cellular competition for resources and tumour responses to hypoxia (low oxygen levels). We conclude our work by summarizing the future steps for the expansion of the current system.

Influence of the Reynolds Number on Spar Vortex Induced Motions (VIM): Multiple Scale Model Test Comparisons

2009 ◽  
Author(s):  
Dominique Roddier ◽  
Tim Finnigan ◽  
Stergios Liapis
Keyword(s):  
Reynolds Number ◽  
Critical Reynolds Number ◽  
Multiple Scale ◽  
Scale Model ◽  
Taylor Model ◽  
Testing Procedures ◽  
Critical Reynolds Numbers ◽  
Number Of Publications ◽  
Six Degree Of Freedom ◽  
First Time

There have been a number of publications on spar Vortex-Induced-Motions (VIM) model testing procedures and results over the past few years. All tests allowing full 6 DOF response to date have been done under sub-critical Reynolds Number conditions. Prior to 2006 tests under super-Critical Reynolds Number conditions had only been done with a fully submerged 1 DOF rig. Early in 2006, a series of Spar VIM experiments was undertaken in three different facilities: Force Technology in Denmark, the David Taylor Model Basin in Bethesda Maryland and UC Berkeley in California. The motivation of this work was to investigate the effect of Reynolds Number and hull appurtenances on spar vortex induced motions (VIM) for a vertically moored 6DOF truss spar hull model with strakes. The three series of tests were done at both sub and super-critical Reynolds Numbers, with matching Froude Numbers. In order to assess the importance of appurtenances (chains, pipes and anodes) and current heading on strake effectiveness, tests were done with several sets of appurtenances, and at various headings and reduced velocities. These experiments were unique and groundbreaking in many ways: • For the first time the issue of scalability of Spar VIM experiments has been addressed and tested in a systematic way. • For the first time the effect of appurtenances (pipes, chains and anodes) was systematically tested. • The model tested at the David Taylor Model Basin (DTMB) had a diameter of 5.8′ and a weight of 15,600 lbs. It is the largest spar model ever tested. Furthermore the DTMB tests series is the only supercritical spar VIM performed with a six degree of freedom (6DOF) rig. This paper describes the three model tests campaigns, focusing on the efforts made to ensure three complete geo-similar programs, and on the significant findings of these tests, effectively that the influence of Re is to add some conservativeness in the results as the testing scale is smaller.

scholarly journals A multiple‐scale model for compressible turbulent flows

1995 ◽  
Vol 7 (3) ◽  
pp. 658-666 ◽  
Author(s):  
William W. Liou ◽  
Tsan‐Hsing Shih ◽  
Beverly S. Duncan
Keyword(s):  
Turbulent Flows ◽  
Multiple Scale ◽  
Scale Model

scholarly journals Collective Cell Migration in a Fibrous Environment: A Hybrid Multiscale Modelling Approach

2021 ◽  
Vol 7 ◽  
Author(s):  
Szabolcs Suveges ◽  
Ibrahim Chamseddine ◽  
Katarzyna A. Rejniak ◽  
Raluca Eftimie ◽  
Dumitru Trucu
Keyword(s):  
Cell Migration ◽  
Experimental Studies ◽  
Collagen Fibre ◽  
Scale Model ◽  
Collective Cell Migration ◽  
Irregular Shapes ◽  
Model Match ◽  
Migration Type ◽  
The Impact ◽  
Different Tissues

The specific structure of the extracellular matrix (ECM), and in particular the density and orientation of collagen fibres, plays an important role in the evolution of solid cancers. While many experimental studies discussed the role of ECM in individual and collective cell migration, there are still unanswered questions about the impact of nonlocal cell sensing of other cells on the overall shape of tumour aggregation and its migration type. There are also unanswered questions about the migration and spread of tumour that arises at the boundary between different tissues with different collagen fibre orientations. To address these questions, in this study we develop a hybrid multi-scale model that considers the cells as individual entities and ECM as a continuous field. The numerical simulations obtained through this model match experimental observations, confirming that tumour aggregations are not moving if the ECM fibres are distributed randomly, and they only move when the ECM fibres are highly aligned. Moreover, the stationary tumour aggregations can have circular shapes or irregular shapes (with finger-like protrusions), while the moving tumour aggregations have elongate shapes (resembling to clusters, strands or files). We also show that the cell sensing radius impacts tumour shape only when there is a low ratio of fibre to non-fibre ECM components. Finally, we investigate the impact of different ECM fibre orientations corresponding to different tissues, on the overall tumour invasion of these neighbouring tissues.

scholarly journals A Multiple Scale Model for Tumor Growth

2005 ◽  
Vol 3 (2) ◽  
pp. 440-475 ◽  
Author(s):  
T. Alarcón ◽  
H. M. Byrne ◽  
P. K. Maini
Keyword(s):  
Tumor Growth ◽  
Multiple Scale ◽  
Scale Model

scholarly journals SANS/WANS Time-resolving Neutron Scattering Studiesof Polymer Phase Transitions Using NIMROD

2013 ◽  
Vol 1528 ◽  
Author(s):  
Geoffrey Robert Mitchell ◽  
Daniel Bowron ◽  
Artur Mateus ◽  
Paulo Bartolo ◽  
Thomas Gkourmpis ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Multiple Scale ◽  
Synthetic Polymers ◽  
Scale Model ◽  
Basic Question ◽  
Lamellar Thickness ◽  
Structural Development ◽  
Length Scales ◽  
Time Resolved ◽  
Target Station

ABSTRACTWe use new neutron scattering instrumentation to follow in a single quantitative time-resolving experiment, the three key scales of structural development which accompany the crystallisation of synthetic polymers. These length scales span 3 orders of magnitude of the scattering vector. The study of polymer crystallisation dates back to the pioneering experiments of Keller and others who discovered the chain-folded nature of the thin lamellae crystals which are normally found in synthetic polymers. The inherent connectivity of polymers makes their crystallisation a multiscale transformation. Much understanding has developed over the intervening fifty years but the process has remained something of a mystery. There are three key length scales. The chain folded lamellar thickness is ∼ 10nm, the crystal unit cell is ∼ 1nm and the detail of the chain conformation is ∼ 0.1nm. In previous work these length scales have been addressed using different instrumention or were coupled using compromised geometries. More recently researchers have attempted to exploit coupled time-resolved small-angle and wide-angle x-ray experiments. These turned out to be challenging experiments much related to the challenge of placing the scattering intensity on an absolute scale. However, they did stimulate the possibility of new phenomena in the very early stages of crystallisation. Although there is now considerable doubt on such experiments, they drew attention to the basic question as to the process of crystallisation in long chain molecules. We have used NIMROD on the second target station at ISIS to follow all three length scales in a time-resolving manner for poly(e-caprolactone). The technique can provide a single set of data from 0.01 to 100Å-1 on the same vertical scale. We present the results using a multiple scale model of the crystallisation process in polymers to analyse the results.

Neutrophil migration through in vitro interstitial matrix

1992 ◽  
Vol 50 (1) ◽  
pp. 894-895
Author(s):  
J. Roemer ◽  
S.R. Simon
Keyword(s):  
Extracellular Matrix ◽  
Smooth Muscle ◽  
Cell Migration ◽  
Smooth Muscle Cells ◽  
Inflammatory Cell ◽  
Neutrophil Migration ◽  
Culture Conditions ◽  
Aortic Smooth Muscle ◽  
Specific Culture

We are developing an in vitro interstitial extracellular matrix (ECM) system for study of inflammatory cell migration. Falcon brand Cyclopore membrane inserts of various pore sizes are used as a support substrate for production of ECM by R22 rat aortic smooth muscle cells. Under specific culture conditions these cells produce a highly insoluble matrix consisting of typical interstitial ECM components, i.e.: types I and III collagen, elastin, proteoglycans and fibronectin.

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