Documents disponibles écrits par cet auteur

Dynamics of stress fibers turnover in contractile cells / Louis Foucard in Journal of engineering mechanics, Vol. 138 N° 10 (Octobre 2012) 

Public ISBD [article]  in Journal of engineering mechanics > Vol. 138 N° 10 (Octobre 2012) . - pp. 1282–1287. Titre : Dynamics of stress fibers turnover in contractile cells Type de document : texte imprimé Auteurs : Louis Foucard, Auteur ; Franck J. Vernerey, Auteur Année de publication : 2012 Article en page(s) : pp. 1282–1287. Note générale : Mécanique appliquée Langues : Anglais (eng) Mots-clés : Mechanobiology  Tissue  engineering  Stress  fiber  Contractile  cells  Cyclic  stretch  Thermodynamics  Biophysics Résumé : Numerous experiments have shown that contractile cells like fibroblasts adapt their internal structure to their microenvironment by generating and orienting a network of stress fibers (SFs). This phenomenon has been modeled in previous studies with stability analysis through calculation of the fiber’s potential or strain energy, where SFs are assigned a constant elasticity. Recent experiments have shown that the elasticity in SFs is rate dependent, resulting in a different stress fiber organization under constant or cyclic stretching. Here, a thermodynamical model that describes the anisotropic polymerization of the contractile units into SFs via the calculation of the mechanochemical potential of the two constituents is proposed. The stretch-dependent part of the SF potential is made of two terms that describe the passive and active behavior of the SF. In this paper, it is shown that the contributions of these two terms vary widely under constant or cyclic stretching as the SFs exhibit a rate-dependent elasticity and lead to two very different anisotropic SF organizations. It is further demonstrated that the substrate stiffness as well as its Poisson’s ratio and anisotropy play a crucial role in the formation and organization of the SFs, consistent with what has been observed in various experiments. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29EM.1943-7889.0000430 [article] Dynamics of stress fibers turnover in contractile cells [texte imprimé] / Louis Foucard, Auteur ; Franck J. Vernerey, Auteur . - 2012 . - pp. 1282–1287. Mécanique appliquée Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 138 N° 10 (Octobre 2012) . - pp. 1282–1287. Mots-clés : Mechanobiology  Tissue  engineering  Stress  fiber  Contractile  cells  Cyclic  stretch  Thermodynamics  Biophysics Résumé : Numerous experiments have shown that contractile cells like fibroblasts adapt their internal structure to their microenvironment by generating and orienting a network of stress fibers (SFs). This phenomenon has been modeled in previous studies with stability analysis through calculation of the fiber’s potential or strain energy, where SFs are assigned a constant elasticity. Recent experiments have shown that the elasticity in SFs is rate dependent, resulting in a different stress fiber organization under constant or cyclic stretching. Here, a thermodynamical model that describes the anisotropic polymerization of the contractile units into SFs via the calculation of the mechanochemical potential of the two constituents is proposed. The stretch-dependent part of the SF potential is made of two terms that describe the passive and active behavior of the SF. In this paper, it is shown that the contributions of these two terms vary widely under constant or cyclic stretching as the SFs exhibit a rate-dependent elasticity and lead to two very different anisotropic SF organizations. It is further demonstrated that the substrate stiffness as well as its Poisson’s ratio and anisotropy play a crucial role in the formation and organization of the SFs, consistent with what has been observed in various experiments. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29EM.1943-7889.0000430

Nonlinear, large deformation finite-element beam/column formulation for the study of the human spine / Franck J. Vernerey in Journal of engineering mechanics, Vol. 136 N° 11 (Novembre 2010) 

Public ISBD [article]  in Journal of engineering mechanics > Vol. 136 N° 11 (Novembre 2010) . - pp.1319-1328 Titre : Nonlinear, large deformation finite-element beam/column formulation for the study of the human spine : investigation of the role of muscle on spine stability Type de document : texte imprimé Auteurs : Franck J. Vernerey, Auteur ; Brian Moran, Auteur Année de publication : 2011 Article en page(s) : pp.1319-1328 Note générale : Mécanique appliquée Langues : Anglais (eng) Mots-clés : Bioengineering  Stability  Finite  element  method  Deformation  Beams  Columns. Résumé : A nonlinear, large deformation beam/column formulation is used to model the behavior of the human spine under compressive load. The stabilizing roles of muscles are accounted for using Patwardhan’s assumption that muscles act to direct the load along the tangent of the column. Three aspects of the spinal structure are then investigated. First, we look at the effects of two different assumptions for the action of muscles, leading to significant differences in the spine behavior. Second, the difference in mechanical properties between the vertebrae and the spinal disks is explored. Third, a nonlinear mechanical response of the spinal disk that arises from a two-step hierarchical homogenization technique is used. It is found that these factors have an important influence on the overall behavior of the spine structure. The present formulation offers a versatile model to investigate various features of the human spine, while remaining affordable computationally. It also provides an interesting framework for future multiscale studies of the human spine. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.org/emo/resource/1/jenmdt/v136/i11/p1319_s1?isAuthorized=no [article] Nonlinear, large deformation finite-element beam/column formulation for the study of the human spine : investigation of the role of muscle on spine stability [texte imprimé] / Franck J. Vernerey, Auteur ; Brian Moran, Auteur . - 2011 . - pp.1319-1328. Mécanique appliquée Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 136 N° 11 (Novembre 2010) . - pp.1319-1328 Mots-clés : Bioengineering  Stability  Finite  element  method  Deformation  Beams  Columns. Résumé : A nonlinear, large deformation beam/column formulation is used to model the behavior of the human spine under compressive load. The stabilizing roles of muscles are accounted for using Patwardhan’s assumption that muscles act to direct the load along the tangent of the column. Three aspects of the spinal structure are then investigated. First, we look at the effects of two different assumptions for the action of muscles, leading to significant differences in the spine behavior. Second, the difference in mechanical properties between the vertebrae and the spinal disks is explored. Third, a nonlinear mechanical response of the spinal disk that arises from a two-step hierarchical homogenization technique is used. It is found that these factors have an important influence on the overall behavior of the spine structure. The present formulation offers a versatile model to investigate various features of the human spine, while remaining affordable computationally. It also provides an interesting framework for future multiscale studies of the human spine. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.org/emo/resource/1/jenmdt/v136/i11/p1319_s1?isAuthorized=no