P transport

Issi, J. -P., Transport properties of metal chloride acceptor graphite intercalation compounds. In Graphite Intercalation Compounds,... 

The ocean system is separated into three major reservoirs that best represent the dominant pools and pathways of P transport within the ocean. The surface ocean reservoir (5) is defined as the upper 300 m of the oceanic water column. As discussed in an earlier section and displayed in Fig. 14-6, the surface layer roughly corresponds to the surface mixed layer where all... 

The basic cycle of P transport from continents to oceans to sediments is then completed by the slow geologic processes that eventually return... 

Lauger, P., Transport noise in membranes, Biochim. Biophys. Acta, 507, 337 (1978). 

M., Artursson, P., Transport and permeability properties of human Caco-2 cells an in vitro model of the intestinal epithelial cell barrier,... 

J., Artursson, P., Transport of celiprolol across human intestinal epithelial (Caco-2) cells mediation of secretion by multiple transporters including P-glycoprotein, Br. J. Pharmacol. 1993, 3 30, 1009-1016. 

Phosphate must be applied as fertilizer to the soil. Ideally it is added in quantities sufficient to guarantee optimal yields, but not in excess in order to avoid P transportation into other compartments of the ecosystem. The amount added should be based on an accurate estimation of the plant-available fraction of P already present in a soil.This is an old and difficult task and a large number of extraction methods have been used since intensive land use was practised. Recently methods have been worked out in which a strip of filter paper impregnated with an Fe oxide (2-line ferri-hydrite) is dipped into a soil suspension and the amount of P adsorbed by the paper is taken as being plant-available (Sissingh,1988 Van der Zee et ah, 1987 Sharpley, 1993 Sharpley et ah,1994 Kuo and Jellum, 1994 Myers et ah 1997). Anion and cation resins extracted more P from four heavily fertilized soils than from goethite (Delgado Torrent, 2000). Other oxyanions adsorbed by soil Fe oxides are silicate, arsenate, chromate, selenite ( ) and sulphate. Adsorption of sulphate led to a release of OH ions and was substantially lowered once the Fe oxides were selectively removed (Fig.16.17). 

Cheremisinoff, N. P., Transportation of Hazardous Materials A Guide to Compliance, Noyes Publications, Park Ridge, New Jersey, 1994. 

Since one starts off with a larger hole concentration in the //-type of material than exists in the //-type of material, there will initially be more holes taking the p — // random walk titan the n — // random walk. One has stated in microscopic language that there will be diffusion of holes in the// —> // direction [Fig. 7.21(b)]. What is the result of this p—m hole diffusion The net p transport of holes leaves a negative charge on the p material and confers a positive charge on the n material [Fig. 7.21(c)]. A potential difference develops [Fig. 7.21(d)]. Further, this charging of the two sides of the interface and the resultant potential difference acts precisely in such a manner as to oppose further //—>// hole diffusion (Fig. 7.22). 

Whittam, R., Wheeler, K. P., Transport Across Cell Membranes, Ann. 

Chapters 14 and 18 Correct values for ATP production resulting from catabolism. Other texts do not take into account the energy required for ATP, ADP, and P transport across the inner mitochondrial membrane. This makes a substantial difference in the calculated energy yields. 

Mechanistic Multiphase Model for Reactions and Transport of Phosphorus Applied to Soils. Mansell et al. (1977a) presented a mechanistic model for describing transformations and transport of applied phosphorus during water flow through soils. Phosphorus transformations were governed by reaction kinetics, whereas the convective-dispersive theory for mass transport was used to describe P transport in soil. Six of the kinetic reactions—adsorption, desorption, mobilization, immobilization, precipitation, and dissolution—were considered to control phosphorus transformations between solution, adsorbed, immobilized (chemisorbed), and precipitated phases. This mechanistic multistep model is shown in Fig. 9.2. 

The functions of PolyPs associated with their anionic nature were also retained. P transported into the lysosomes of human fibroblasts incorporates high-polymer PolyPs synthesized in these organelles (Pisoni and Lindley, 1992). Lysosomes are a storage compartment for bioactive amines, and PolyPs might be able to form complexes with these compounds. A similar process of PolyP synthesis was also observed in granulocytes (Cowling and Birnboim, 1994). 

Some authors doubt the possibility of a direct interrelation between PolyP and photosynthesis in algae (Rubtsov et al, 1977 Rubtsov and Kulaev, 1977). The following facts support this point of view. No high-molecular-weight PolyP was found in the chloroplasts of Acetabularia mediterranea (Rubtsov et al, 1977). The inhibitor analysis and detection of polyphosphate kinase activity in this alga (Rubtsov and Kulaev, 1977) point to the fact that PolyP is not directly, but rather indirectly, connected with the photosynthesis through the formation of ATP, which provides energy for P transport and PolyP synthesis. 

Danesi, P.R., Horwitz, E.P., and Rickert, P., Transport of Eu through a bis(2-ethyUiexyl)phosphoric acid/n-dodecane solid supported liquid membrane. Sep. Set Tech., 1982, 17 1183-1192. 

The operation of the cell is illustrated in Figs. 6.2b and c the band alignment of the transport layers with respect to the absorber and the electric field across the absorber is such that fast separation of the photogenerated carriers is supported. Electrons will be driven towards the -type transport layer and subsequently to the n-contact, while holes can only enter the p-transport layer and then reach the p-contact. As the absorber layer is embedded between two transparent transport layers, a light ray can pass through the highly folded absorber several times. The local absorber thickness in this configuration is therefore thinner than the total optical thickness. 

Petrak K, Goddard P. Transport of macromolecules across the capillary walls. Adv Drag Deliv Rev 1989 3 191-214. 

Solute transport in soils may be complicated by precipitation reactions that act as kinetic sinks for chemicals. Because of its agronomic and environmental significance, P precipitation reactions during transport in soil have been most frequently studied. Often P is a severely limited nutrient in terrestrial and aquatic ecosystems which adversely affects plant and fish production. Because of the significance of P precipitation reactions in soil, the biogeochemical and hydrologic processes controlling P transport must be clearly understood. Many of the principles to be discussed for P reactions, may in some instances be applicable to other types of precipitation reactions (i.e., Al, Fe, etc.)... 

Gawronski R, Religa P. Transport mechanism of chromium(III) through the unmixed bulk liquid membrane containing dinonylnaphthalenesulfonic acid as a carrier. J Membr Sci 2007 289 187-190. 

Nielsen, J.S., joner, E.J., Declerck, S., Olsson, S. and Jakobsen, I. (2002) Phospho-imaging as a tool for visualisation and non-invasive measurement of P transport dynamics in arbuscular mycor-rhiza. New Phytologist 1 54, 809-81 9. 

Interspecific variation, which may be considerable with respect to P transport, is still poorly known in terms of AM transport of metals. Single AM fungal species are commonly used in most laboratory experiments, but this may not reflect the real situation in situ. The development of molecular techniques (Redecker et al,... 

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