Force-velocity relation

An even more approximate relation is obtained by keeping the linear terms only  

In the following a set of compatible values for gH o and s will be determined using the measured value of a = 4.8iV with the assumption that only 10% of the total power output of the proton circuit is dissipated 

The parameter s can be determined using the relation a = given after Eq. (13). With F=0.9Fh s=USNV-  

The above estimates are mainly intended to give the idea of the orders of magnitudes of the quantities. It is seen from Eq. (8) that ot/C h + o) must be less than unity for the expression to converge rapidly. With the above given estimates it is true only for small velocities of shortening (t 2cms ). Presumably both Fh and gn have been underestimated above by about 10% or more and the value of s would be less than that given above. 

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M. Dogterom and B. Yurke, Measurement of the force-velocity relation for growing microtubules. Science 278, 856-860 (1997). 

Applegate D, Pardee JD (1992) Actin-facilitated assembly of smooth muscle myosin induces formation of actomyosin fibrils. J Cell Biol 117 1223-1230 Arner A, Hellstrand P (1985) Effects of calcium and substrate on force-velocity relation and energy turnover in skinned smooth muscle of the guinea-pig. J Physiol 360 347-365... 

Arner A (1983) Force-velocity relation in chemically skinned rat portal vein. Effects of Ca and Mg. Pflugers Arch 397 6-12... 

SonnenbHck, E.H. 1962. Force-velocity relations in mammahan heart muscle. Am. J. Physiol. 202 931... 

SugaH. and Sagawa K. 1972. Mathematical interrelationship between instantaneous ventricular pressure-volume ratio and myocardial force-velocity relation. Ann. Biomed. Eng. 1 160. 

Comparison between predicted (Equation 18.1) and measured pressure curves exposed the so-called ejection effect early into ejection the predicted pressure is higher, later in ejection it is lower than the measured one (akin to Hill s 1938 force-velocity relation). To include the ejection effect quantitatively, the function f(t) must be modified and Equation 18.1 becomes... 

Under conditions of constant load the relationship between force and velocity is nearly hyperbolic [Hill, 1938], The shortening force-velocity relation was can be described by ... 

Ross J, Covel JE, Sonnenblick EH, Braunwald E (1966) Contractile state of the heart characterised by force velocity relations in variably afterloaded and isovolumic beats. Circ Res 18 149-163 Ruch TC, Patton HD (1974) Physiology and Biophysics. Philadelphia, London WB Saunders Co., p 329... 

Since we are interested in cellular activities where several motors could be involved, a simplified mean-filed model emerge with the assumption that motors a) work independent of each other b) share the applied load equally. These equations are able to predict the transport properties of cargo particles such as their effective velocity and average run length. Two most important quantities that need to be mentioned here are the force-velocity relation and detachment rate of motor when a load is applied to the cargo. Several experiments have shown that velocity Vn(F) of a single motor in system of n bound motors decreases almost linearly with the force F applied against the motor movement. 

Muscle contraction dynamics include the mechanical properties of muscle tissues and tendons, which are expressed as force-length and force-velocity relations. The activation dynamics include the voluntary and nonvoluntary (reflex) excitation signal and motor unit recruitment level in the muscle. It is well known that regardless of fatigue, the generated torque in each joint is dependent on muscle activation levels (MALs) and joint angle when in a stationary position. This was first observed by Tnman et al. 

Experimental testing (Seleemah and Constantinou 1997) has shown that the behaviOT of viscous fluid dampers corresponds to a nonlinear viscous dashpot and can be modeled by the following nonlinear force-velocity relation ... 

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