The role of a stiffening extra-cellular matrix (ECM) in cancer progression is documented but poorly understood. Here we use a conditioning protocol to test the role of nonmuscle myosin II isoforms in cell mediated ECM arrangement using collagen constructs seeded with breast cancer cells expressing shRNA targeted to either the IIA or IIB heavy chain isoform. While there are several methods avail...

Stiffness matrix of the four-node quadrilateral plane stress element is decomposed into normal and shear components. A computer program is developed to obtain the straining modes using adequate and reduced integration. Then a solution for the problem of mixing straining modes is found. Accuracy of the computer program is validated by a closed-form stiffness matrix, derived for the plane rectang...

A novel bio-magnetomechanical microtissue system is described for magnetic actuation of arrays of 3D microtissues using microcantilevers. This system enables both in situ measurements of fundamental mechanical properties of engineered tissue, such as contractility and stiffness, as well as dynamic stimulation of the microtissues. Using this system, cell and extracellular matrix contributions to...

by minimizing the total potential energy function and deploying the virtual work principle, a higher-order stiffness matrix is achieved. this new tangent stiffness matrix is used to solve the frame with geometric nonlinear behavior. since authors’ formulation takes into account the higher-order terms of the strain vector, the convergence speed of the solution process will increase. in fact, bot...

The force regulation and inevitable positional inaccuracy of traditional control system can be compensated by the compliance/stiffness mechanism. The compliance/stiffness of a robotic mechanism is usually modeled by a 6 by 6 symmetric positive definite matrix at an equilibrium point using screw theory. When an external wrench is exerted on the mechanism and the mechanism moves away from its equ...

The effects of dynamic loading on crack breathing mechanisms are not yet thoroughly examined in literature. This paper introduces a parameter relating crack direction to bending load direction in order to model breathing behaviour of fatigue cracks subject to mass unbalance. Crack states (open, partial and closed) for shafts subject to weight-to-unbalance force ratios of 0.5, 1 and 2 and unbala...

A completely general method of analysis for three-dimensional raked piles under harmonic excitation is discussed. The piles have been represented by a three-dimensional frame structure and the soil has been represented by a boundary element discretization scheme. A computer program has been written which carries out this analysis and produces a group stiffness matrix that can be included as a f...

Tumor microvasculature tends to be malformed, more permeable, and more tortuous than vessels in healthy tissue, effects that have been largely attributed to up-regulated VEGF expression. However, tumor tissue tends to stiffen during solid tumor progression, and tissue stiffness is known to alter cell behaviors including proliferation, migration, and cell-cell adhesion, which are all requisite f...

Matrix stiffness is a well-established instructive cue in two-dimensional cell cultures. Its roles in morphogenesis in 3-dimensional (3D) cultures, and the converse effects of cells on the mechanics of their surrounding microenvironment, have been more elusive given the absence of suitable methods to quantify stiffness on a length-scale relevant for individual cell-extracellular matrix (ECM) in...

By minimizing the total potential energy function and deploying the virtual work principle, a higher-order stiffness matrix is achieved. This new tangent stiffness matrix is used to solve the frame with geometric nonlinear behavior. Since authors’ formulation takes into account the higher-order terms of the strain vector, the convergence speed of the solution process will increase. In fac...