Nonzero entities

Carrier-mediated passage of a molecular entity across a membrane (or other barrier). Facilitated transport follows saturation kinetics ie, the rate of transport at elevated concentrations of the transportable substrate reaches a maximum that reflects the concentration of carriers/transporters. In this respect, the kinetics resemble the Michaelis-Menten behavior of enzyme-catalyzed reactions. Facilitated diffusion systems are often stereo-specific, and they are subject to competitive inhibition. Facilitated transport systems are also distinguished from active transport systems which work against a concentration barrier and require a source of free energy. Simple diffusion often occurs in parallel to facilitated diffusion, and one must correct facilitated transport for the basal rate. This is usually evident when a plot of transport rate versus substrate concentration reaches a limiting nonzero rate at saturating substrate While the term passive transport has been used synonymously with facilitated transport, others have suggested that this term may be confused with or mistaken for simple diffusion. See Membrane Transport Kinetics... 

The adhesive force between a neutral particulate contaminant and the wafer is expected to be due to the attractive Van der Waal s interaction between molecules.This is a macroscopic force found by averaging over the force between all the molecules of a particle and the neighboring surface. For a spherical particle sitting on a flat wafer, it is known that surface roughness will cause the mean distance of separation between the particle and the wafer to be nonzero. The attractive force between these two entities acts along the normal between the sphere and the wafer, and is given by ... 

In the structure factor equation the coefficients in the summation were all nonzero electron densities fj occurring at Xj, yj, Zj, which is really p(xj, yj, zj), and Fhki were the entities being calculated. Hence the coefficients in the electron density equation yielding p(x, y, z) must be the reciprocal space entities Fhki Finally, to keep units consistent, and the mathematics consistent with Monsieur Fourier, the sign of the imaginary term must be changed to minus, and the constant V must be inverted to 1/V, the volume of the reciprocal unit cell. Thus the electron density equation assumes the form. 

In contrast, the term transition state refers to the properties of an ensemble of molecular entities at a finite (nonzero) temperature it may be associated with the maximum along a simulated free energy profile for an elementary step. We consider it useful to distinguish the two concepts in view of the significant difference between them the one is microscopic and related to a feature of an (unobservable)... 

Although both photons and electrons show an apparent duality, they are not the same kinds of entities. Photons always travel at speed c and have zero rest mass electrons always have v < c and a nonzero rest mass. Photons must always be treated relativistically, but electrons whose speed is much less than c can be treated nonrela-tivistically. 

The continuous PDE of Equation 26.1 must be coupled and solved together with the CA model that treats cells as discrete entities. Thus, the migrating and proliferating cells must be considered as moving sinks (and/or sources) for the convection-diffusion-reaction problem and the cell density p j is actually a discontinuous function that is nonzero only in lattice sites occupied by cells ... 

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