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Spatial patterns of cellular growth generate mechanical stresses that help to push, fold, expand, and deform tissues into their specific forms. Genetic factors are thought to specify patterns of growth and other behaviors to drive morphogenesis. Here, we show that tissue form itself can feed back to regulate patterns of proliferation. Using(More)
We investigated the mechanotransduction pathway in endothelial cells between their nucleus and adhesions to the extracellular matrix. First, we measured nuclear deformations in response to alterations of cell shape as cells detach from a flat surface. We found that the nuclear deformation appeared to be in direct and immediate response to alterations of the(More)
Protrusions are deformations that form at the surface of living cells during biological activities such as cell migration. Using combined optical tweezers and fluorescent microscopy, we quantified the mechanical properties of protrusions in adherent human embryonic kidney cells in response to application of an external force at the cell surface. The(More)
  • A A Spector
  • 1999
A nonlinear electroelastic model for the composite wall of the cochlear outer hair cell is proposed. The cell wall is modeled as a two-layer shell with elastic connections between the layers: an active layer corresponds to the plasma membrane and a passive layer corresponds to a combination of the cytoskeleton and the subsurface cisternae. As a basis of the(More)
Outer hair cell electromotility is crucial for the amplification, sharp frequency selectivity, and nonlinearities of the mammalian cochlea. Current modeling efforts based on morphological, physiological, and biophysical observations reveal transmembrane potential gradients and membrane tension as key independent variables controlling the passive and active(More)
Membrane protein prestin is a critical component of the motor complex that generates forces and dimensional changes in cells in response to changes in the cell membrane potential. In its native cochlear outer hair cell, prestin is crucial to the amplification and frequency selectivity of the mammalian ear up to frequencies of tens of kHz. Other cells(More)
The passive and active properties of the cochlear outer hair cell are studied. The outer hair cell is currently considered the major candidate for the active component of mammalian hearing. Understanding of its properties may explain the amplification and sharp frequency selectivity of the ear. To analyse the cell behaviour, a model of a nonlinear(More)
The electrical properties of the cellular membrane are important for ion transport across cells and electrophysiology. Plasma membranes also resist bending and stretching, and mechanical properties of the membrane influence cell shape and forces in membrane tethers pulled from cells. There exists a coupling between the electrical and mechanical properties(More)
The low-pass voltage response of outer hair cells predicted by conventional equivalent circuit analysis would preclude the active force production at high frequencies. We have found that the band pass characteristics can be improved by introducing the piezoelectric properties of the cell wall. In contrast to the conventional analysis, the receptor potential(More)
We consider the mechanical properties of the outer hair cell cytoskeleton. The cytoskeleton is represented as a set of microdomains of different sizes and orientations composed of actin filaments and spectrin crosslinks. An intermediate material between domains is also introduced. The domain characteristics are randomly generated and the histograms of the(More)