Focal adhesions (FA) are large, multiprotein complexes that provide a mechanical link between the cytoskeletal contractile machinery and the extracellular matrix. FA exhibit mechanosensitive properties; they self-assemble and elongate upon application of pulling forces and dissociate when these forces are decreased. We propose a thermodynamic model for the mechanosensitivity of FA, according to...

Chronic low back pain (CLBP), one of the most common musculoskeletal conditions in older adults, might affect balance and functional independence. The purpose of this study was to investigate the postural responses to a suddenly released pulling force in older adults with and without CLBP. Thirty community-dwelling older adults with CLBP and 26 voluntary controls without CLBP were enrolled. Par...

We performed molecular dynamics simulations and theoretical analysis of nanoparticle pulling off from adhesive substrates. Our theoretical model of nanoparticle detachment is based on the Kramers' solution of the stochastic barrier crossing in effective one-dimensional potential well. The activation energy, ΔE, for nanoparticle detachment first decreases linearly with increasing the magnitude o...

Mechanical forces exerted by laser tweezers or atomic force microscopes can be used to drive rare transitions in single molecules, such as unfolding of a protein or dissociation of a ligand. The phenomenological description of pulling experiments based on Bell's expression for the force-induced rupture rate is found to be inadequate when tested against computer simulations of a simple microscop...

As a widely used precipitation agent for DNA extraction, ethanol is used to induce single molecule DNA condensation. This process is studied with force-measuring magnetic tweezers and atomic force microscopy (AFM). Our experiments provide direct evidence of the metastable intermediate racquet states in DNA collapse induced by ethanol. The measured condensing force is less than 0.2 pN even at 50...

Pushing and pulling during manual material handling can increase the compressive forces on the lumbar disc region while creating high shear forces at the shoe-floor interface. A sagittal plane dynamic model derived from previous biomechanical models was developed to predict L5/S1 compressive force and required coefficients of friction during dynamic cart pushing and pulling. Before these predic...

In this paper we investigate whether remote touch in the form of force feedback from another player’s actions can enhance feelings of social presence and enjoyment of a collaborative, spatially distributed rope pulling game. Dyads of players situated in different rooms were either given an ‘elastic band’ type force feedback, or were given force feedback of the other player’s actions (i.e. remot...

An Ising-like model of proteins is used to investigate the mechanical unfolding of the green fluorescent protein along different directions. When the protein is pulled from its ends, we recover the major and minor unfolding pathways observed in experiments. Upon varying the pulling direction, we find the correct order of magnitude and ranking of the unfolding forces. Exploiting the direction de...

Single-molecule force spectroscopy is providing unique, and sometimes unexpected, insights into the free-energy landscapes of proteins. Despite the complexity of the free-energy landscapes revealed by mechanical probes, forced unfolding experiments are often analyzed using one-dimensional models that predict a logarithmic dependence of the unfolding force on the pulling velocity. We previously ...

Interaction between polymers and soft-matter surfaces in the biological cell is a common yet incompletely understood phenomenon. This work investigates a generic situation where a thermoresponsive polymer gel is placed in the vicinity of an adsorbing surface, and starts contracting. The force is mediated by polymer chains that partially attach to the surface and partially to the contracting gel...