Maintaining undifferentiated mouse embryonic stem cell (mESC) culture has been a major challenge as mESCs cultured in Leukemia Inhibitory Factor (LIF) conditions exhibit spontaneous differentiation, fluctuating expression of pluripotency genes, and genes of specialized cells. Here we show that, in sharp contrast to the mESCs seeded on the conventional rigid substrates, the mESCs cultured on the...

In the context of global/goal-oriented error estimation applied to computational mechanics, the need to obtain reliable and guaranteed bounds on the discretization error has motivated the use of residual error estimators. These estimators require the construction of admissible stress fields verifying the equilibrium exactly. This article focuses on a recent method, based on a flux-equilibration...

[1] The presence of deeply penetrating continental roots may locally increase the magnitude of basal shear tractions by up to a factor of 4 compared to a layered viscosity structure. Here we examine how these increases in mantlelithosphere coupling influence stress patterns in the overlying elastic lithosphere. By coupling a mantle flow model to a model for the elastic lithosphere, we show that...

[1] We provide new insights into the lithosphere-mantle coupling problem through a joint modeling of lithosphere dynamics and mantle convection and through comparison of model results with the high resolution velocity gradient tensor model along the Earth’s plate boundary zones. Using a laterally variable effective viscosity lithosphere model, we compute depth integrated deviatoric stresses ass...

Recent technological improvements in the elastic substrate method make it possible to produce spatially resolved measurements of the tractions exerted by single motile cells. In this study we have applied these developments to produce maps of the tractions exerted by 3T3 fibroblasts during steady locomotion. The resulting images have a spatial resolution of approximately 5 micrometers and a max...

Earlier results [1,2]2 on safe loads for a Prandtl-Reuss material subject to surface tractions or displacements which increase in ratio are here extended to any perfectly plastic material and any history of loading.

The secular equation for surface acoustic waves propagating on a monoclinic elastic half-space is derived in a direct manner, using the method of first integrals. Although the motion is at first assumed to correspond to generalized plane strain, the analysis shows that only two components of the mechanical displacement and of the tractions on planes parallel to the free surface are nonzero. Usi...

As a wound heals, or a body plan forms, or a tumour invades, observed cellular motions within the advancing cell swarm are thought to stem from yet to be observed physical stresses that act in some direct and causal mechanical fashion. Here we show that such a relationship between motion and stress is far from direct. Using monolayer stress microscopy, we probed migration velocities, cellular t...

Abstract-We analyze a three-dimensional frictional contact problem between a homogeneous and isotropic linear elastic body and a substrate consisting of a homogeneous and isotropic linear elastic half-space coated with a transversely isotropic elastic layer. The problem formulation includes the kinematics of the body, including its rolling/sliding on the substrate. Expressions relating the disp...

We have measured the traction forces generated by fibroblasts using a novel micromachined device that is capable of determining the subcellular forces generated by individual adhesive contacts. The front of migrating fibroblasts produced intermittent rearward forces whereas the tail produced larger forward directed forces. None of the forces were steady; they all had periodic fluctuations. The ...