Distributions, of transporters

The uptake of energy substrates by brain cells is influenced by the type and distribution of transporters unique to each cell type 533... 

A common problem encountered in large chemical companies involves the distribution of a single product (30 manufactured at several plant locations. Generally, the product needs to be delivered to several customers located at various distances from each plant. It is, therefore, desirable to determine how much Y must be produced at each of m plants (Yv Y2,..., Ym) and how, for example, Ym should be allocated to each of n demand points (YmV Ym2,. Ymnl The cost-minimizing solution to this problem not only involves the transportation costs between each supply and demand point but also the production cost versus capacity curves for each plant. The individual plants probably vary with respect to their nominal production rate, and some plants may be more efficient than others, having been constructed at a later date. Both of these factors contribute to a unique functionality between production cost and production rate. Because of the particular distribution of transportation costs, it may be... 

Trap-Controlled Hopping. In trap-controlled hopping, the scenario described for trap-controlled band mobility applies. However, the microscopic mobility is associated now with carriers hopping in a manifold of localized states. Overall temperature and field dependence reflects the complicated convolution of the temperature and field dependence of both the microscopic mobility and the trap kinetic processes. Glearly, the observed behavior can now range from nondispersive to anomalously dispersive behavior as before, depending on the energy distribution of transport-interactive traps. 

Analyzing the self-diffusion behavior of guest molecules in a microporous catalyst by the combined application of pulsed-field gradient NMR selfdiffusion techniques reveals the spatial distribution of transport resistances over the catalyst particles. In the case of coke deposits on ZSM-5, the distribution of carbonaceous residues over the crystal was found to be a function of the crystal morphology, the time onstream, and the chemical nature of the coke-producing reactant. In the case of ZSM-5 modified by H3PO4, the spatial distribution of the P compounds over the ZSM-5 crystals can be determined by self-diffusion measurements. Location of transport hindrances in a zeolite framework is based on self-diffusion measurements, in... 

An overview of several possible transport routes is given in Figure 10.2. During various disease states, alterations in the levels or distribution of transporters can be seen. Tight junctions limit the paracellular diffusion of molecules and the formation of extracellular fluid [47]. 

Abstract It is demonstrated that the approximate means of quantifying hydrodynamic control of retention is reasonably accurate for low values of the transport resistance on the lOOm and lOOOm scales for high values, the approximate expression may significantly underestimate retention. Our results emphasize the need for further development of practical methodologies for quantifying statistical distributions of transport resistance by effectively combining field measurements, numerical simulations and theoretical/analytical considerations. 

Natural attenuation is controlled by numerous processes, which include sorption, intraparticle diffusion as weU as biological and chemical degradation. In order to be able to quantify respectively predict the fate and transport of contaminants, appropriate models that are able to deal with the complexity and interactions of the involved processes need to be developed. Due to insufficient information on the spatial distribution of transport parameters in the subsurface, stochastic methods are a preferred alternative to deterministic approaches. In the present paper a one-dimensional Lagrangian streamtube model is used to describe the reactive transport of acenaphthene as a sample organic compoimd at field scale. As the streamtube model does not consider the heterogeneity of hydrogeochemical parameters but only hydraubc heterogeneity, model results from the streamtube model are compared in a Monte Carlo approach to results of a two-dimensional Eulerian model. 

FIGURE 7.10 Schematic description of a thin film device being composed of a distribution of transport pathways (mobility values). 

The pore-size distribution of transport pores can be provided by the liquid expulsion permporometry (LEPP) based on Washburn equation for individual groups of pores. LEPP has been commonly used for description of textile materials, porous filtration - in general, for very thin porous materials. Recently, we have shown [12] that LEPP could be used also for other porous material (e.g. pelleted porous eatalysts, adsorbents, etc). 

Fig. 6 shows the pore size distribution of transport-pore radii from LEPP for three porous samples. When comparing transport-pore radii from diffusion and pomeation measurements with these distributions the size and shape of confidence regions (Fig. 5) have to be taken into account as well as the above arguments concerning the validity of ()p. Therefore, the agreement of pore-size distribution of transport pores with ()d is excellent and ()p is a little worse. 

Textural properties of six porous materials with mono- and bidisperse porous structure and a range of pore radii from nanometers to microns were determined by mercury porozimetry and helium pycnometry. The obtained pore-size distributions were compared with transport characteristics obtained independently from diffusion and permeation measurements. For three chosen samples the distribution of transport-pores was obtained from LEPP. 

Martens suggests that a social justice approach would focus on the distribution of transport investments over population groups and the related performance of the network for each of these groups. (Martens 2006 7) Below I will demonstrate how the designers of Transmilenio not only attempted to distribute the investments in a more socially just manner, but also how they attempted to do it by design. 

In the hopping picture, understanding the factors that limit charge-carrier mobility in polymers not only demands knowledge of the distribution of transport parameters, but also their time dependence. The latter is an important hint as to whether or not the hopping picture is justified to begin with, since there is no theoretical... 

Transmembrane transport is essential to virtually all of the useful functions provided by LAB, and the presence of these transporters must reflect the evolutionary histories of the organisms in which they are found (Ren and Paulsen 2005). In earlier work we summarized some of the unusual complement of transporters encoded within LAB genomes, sequenced by the LAB genome consortium (Markarova et al. 2006 Lorca et al. 2007, 2010). In this chapter we report analyses of the distributions of the various transporters found in 11 LAB, their associations with the different transporter families, and their functional significance. We show that LAB have most unusual distributions of transporters, compared to other bacterial types, including actinobacteria. Gram (-) bacteria, and archaea, and we provide potential evolutionary explanations. 

Why do LAB have proportions of transporters so different from those of other bacteria, and why do they have a rich supply of transporters, some of which are normally found only in eukaryotes Perhaps their complement of transporters reflects their unusual life-styles in association with plants and animals. But why do they have distributions of transporter types that differ so much from other microbes, and sometimes from each other The obvious generalized answer has to be EVOLUTION,... 

The differences in scaling behavior for normal gases and liquids at small 0p have important consequences for the distribution of transport resistance in subsequent layers. This is demonstrated in the next two paragraphs where two typical examples are discussed for the initial optimization of multilayer stmctures The resistance of the same mesoporous structure is found to be relatively unimportant for the gas separation application while it provides a major contribution for liquid permeation. 

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