Mechano-chemical coupling

The ability of dyneins to effect mechano-chemical coupling—i.e., motion coupled with a chemical reaction—is also vitally important inside eukaryotic cells, which, as already noted, contain microtubule networks as part of the cytoskele-ton. The mechanisms of intracellular, microtubule-based transport of organelles and vesicles were first elucidated in studies of axons, the long pro-... 

Here,, is the mobility coefficient, while L22 is a generalized mobility relating ATP consumption and the chemical potential difference, and /., 2 and L2] are the mechano-chemical coupling coefficients. A given motor/filament system can work in different regimes, and in a regime where the work is performed by the motor, efficiency is defined by... 

Fig. 12.6. Direct determination of mechano-chemical coupling of myosin, (a) An experimental arrangement for simultaneous measurement. Single-headed myosin in the co-filament with an excess myosin rod is immobilized on the pedestal of the slide glass. An actin filament is manipulated by a trapped laser through two beads attached at both ends to interact with a myosin head in the correct arrangement. The ATP turnover is measured by monitoring the fluorescence from Cy3-ATP (Cy3-ADP) associated to and dissociated from the myosin head using TIRF microscopy, (b) Time trajectory of the displacement of the myosin head and the ATP turnover. The upper, middle, and bottom trace show the time course of displacements, changes in stiffness, which was calculated from the variance of the thermal motion of the beads, and changes in the fluorescence intensity of Cy3-nucleotide at the position of the myosin head...

Mechano-chemical Coupling in Cross-linked 4% Glu-Polypentapeptide Due to Changes in pH at 37°C... 

Figure 9. Mechano-chemical coupling by 20Mrad y-irradiation cross-linked of poly[0.8(GVGVP), 0.2(GEGVP)] under isotonic (A) and isometric (B) conditions. In part B under isometric contraction conditions there occurs an increase in entropic elastic force resulting from a decrease in entropy of...

This technique was introduced in [6] and applied there and in [7 ] to the study of the stability to the formation of textural patterns of the uniform state of a rock under stress. This is clearly a rather powerful technique for analyzing these phenomena in random elastic or other media and must be investigated in greater detail to completely unravel all the effects contained in the mechano-chemical coupling that can lead to pattern formation in stressed rocks. In the next two sections we investigate the application of these concepts to metamorphic layering and stylo-lization. 

THEORETICAL AND FINITE ELEMENT MODELS FOR COUPLED ELECTRO-MECHANO-CHEMICAL TRANSPORT IN SOFT TISSUES... 

Abstract A general theoretical and finite element model (FEM) for soft tissue structures is described including arbitrary constitutive laws based upon a continuum view of the material as a mixture or porous medium saturated by an incompressible fluid and containing charged mobile species. Example problems demonstrate coupled electro-mechano-chemical transport and deformations in FEMs of layered materials subjected to mechanical, electrical and chemical loading while undergoing small or large strains. 

Osteocytes are formed by the incorporation of osteoblasts into bone matrix. They remain in contact with other osteocytes via gap junction-coupled cell processes that form small channels through the matrix, the canaliculi. These small channels connect the cell body containing lacunae with each other and ECM external to the bone and play an important role in mechano-chemical transduction. 

Dusseault, M.B. 2003. Coupled Thermo-mechano-chemical Processes in Shales The Petroleum Borehole. Proceedings GeoProc 2003, Stockholm, Sweden, 8 p. 

COUPLED THERMO-MECHANO-CHEMICAL PROCESSES IN SHALES THE PETROLEUM BOREHOLE... 

Both protein machines of ATP synthase are rotary motors, made possible by the mechanical coupling of chemo-mechanical transduction due to the Fo-motor to mechano-chemical transduction of the Fi-motor. A single rotor driven by the membranous Fo-motor in turn drives the extramembranous Fj-motor. The Fo-motor of yeast mitochondria, for example, exhibits a 10-fold rotational symmetry, providing a 10-step rotary engine, whereas the Fi-motor of all ATP synthases exhibits a threefold rotational symmetry, resulting in a threefold rotary engine. 

Production of hydrodynamic flows coupled to mechano-chemical... 

Simon, B.R., Radtke, G.A., Rigby, Williams, S. K. and Liu, Z.P. (2002) Extended LMPH-ETS finite element models for coupled mechano-electro-chemical transport in soft tissues. ASME BED IMECE 2002-32604, Scott, E., editor... 

Photoelectrochemical water splitting Photocatalytic water splitting Coupled photovoltaic - electrolysis systems Thermochemical conversion Photobiological methods Molecular artificial photosynthesis Plasma-chemical conversion Mechano-catalytic, magnetolysis, radiolysis, etc. 

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