Retarded mobility

The ability to discern changes in the regulation of protein expression, not only by the use of antibodies, but also by means of Northern blotting techniques to monitor changes in mRNA levels, and footprinting techniques or gel retardation/ mobility shift assays to determine interaction of regulatory proteins with nucleic acids. 

The mechanism of polyoondensation reactions is thought to parallel that of the low-molecular-weight analogs. As a result of their macromolecular nature, polymers would be expected to have retarded mobility. It was therefore predicted, purely on theoretical arguments, that the chemical reactivity of polymers should be low. 

It will be recalled that food mobilization in barley, rice and wheat does not occur in endosperms from which the embryo has been removed. This is an easy way to demonstrate that the embryo is responsible for the initiation (and subsequent control) of reserve breakdown. The same simple method has been applied for other seeds, with variable success, but in many cases removal of the embryo has been found to prevent or retard mobilization and adversely to affect development of the requisite enzymes. 

Antlblaze 19. Antiblaze 19 (Mobil), a flame retardant for polyester fibers (134), is a nontoxic mixture of cycHc phosphonate esters. Antiblaze 19 is 100% active, whereas Antiblaze 19T is a 93% active, low viscosity formulation for textile use. Both are miscible with water and are compatible with wetting agents, thickeners, buffers, and most disperse dye formulations. Antiblaze 19 or 19T can be diffused into 100% polyester fabrics by the Thermosol process for disperse dyeing and printing. This requires heating at 170—220°C for 30—60 s. 

As the polymerization reaction proceeds, scosity of the system increases, retarding the translational and/ or segmental diffusion of propagating polymer radicals. Bimolecular termination reactions subsequently become diffusion controlled. A reduction in termination results in an increase in free radical population, thus providing more sites for monomer incorporation. The gel effect is assumed not to affect the propagation rate constant since a macroradical can continue to react with the smaller, more mobile monomer molecule. Thus, an increase in the overall rate of polymerization and average degree of polymerization results. 

Rodbard and Chrambach [77,329] developed a computer program that allows the determination of molecular parameters, i.e., free mobility, molecular radii, molecular weight, and charge or valence, from measured electrophoretic mobilities in gels with different monomer concentrations. For a set of mobility versus gel concentration data they used the Ferguson [18,115,154] equation to obtain the retardation constant from the negative slope and the free mobility from the extrapolated intercept. From the retardation constant they determined the molecular radius using... 

Type II refers to the case in which the isotherms for both cations increase with increasing concentration of the respective cations. Such isotherms have been found for (Li, K)F,j2 (Li, K)(S04)i/2, (Na, K)OH, (Ag, Cs)Br, - (Ag, Na)I, - (Ag, K)I, - " and (Ag, CS)I. In charge asymmetric systems such as (K, Ca 2)CI, such isotherms also usually appear. A common feature of these type II systems is the particularly strong interaction of one cation with the common anion compared with that of the second cation with the anion. The strongly interacting cation will retard the internal mobility of the second cation. This is called the tranquilization effect, and will be explained in Section III.5( 70-... 

The ionic mobilities Uj depend on the retarding factor 0 valid for a particular medium [Eq. (1.8)]. It is evident that this factor also influences the diffusion coefficients. To find the connection, we shall assume that the driving force of diffusion is the chemical potential gradient that is, in an ideal solution,... 

Pelander et al. [71] studied the retardation behavior of cyanobacterial hepato-toxins in the irregular part of the PRISMA model for TLC at 16 selectivity points. The mobile phase combination and the area of the triangular plane were selected in the preassay. The retardation of all the toxins followed the relation for ftRp. The cyanobacterial hepatotoxins behaved predictably in the selected systems in the irregular part of the PRISMA model. 

Pelander et al. [81] developed a computer program for optimization of the mobile phase composition in TLC. They used the desirability function technique combined with the PRISMA model to enhance the quahty of TLC separation. They apphed the statistical models for prediction of retardation and band broadening at different mobile phase compositions they obtained using the PRISMA method the optimum mobile phase mixtures and a good separation for cyanobacterial hepatotoxins on a normal phase TLC plate and for phenolic compound on reversed-phase layers. 

In certain formations, oil recovery can be reduced by coning of either gas downward or water upward to the interval where oil is being produced. Therefore, a need exists for a low-cost injectant that can be used to establish a horizontal pad of low mobility fluid to serve as a vertical barrier between the oil producing zone and the zone where coning is originating. Such low mobility fluid would retard vertical coning of gas or water, thereby improving oil production. 

Flow movement also has a relationship with the electrokinetic phenomenon, which can promote or retard the motion of the fluid constituents. Electrokinetic effects can be described as when an electrical double layer exists at an interface between a mobile phase and a stationary phase. A relative movement of the two phases can be induced by applying an electric field and, conversely, an induced relative movement of the two will give rise to a measurable potential difference.33... 

The final class of polymers containing carboranyl units to be mentioned here is the polyphosphazenes. These polymers comprise a backbone of alternating phosphorous and nitrogen atoms with a high degree of torsional mobility that accounts for their low glass-transition temperatures (-60°C to -80°C). The introduction of phenyl-carboranyl units into a polyphosphazene polymer results in a substantial improvement in their overall thermal stability. This is believed to be due to the steric hindrance offered by the phenyl-carborane functionality that inhibits coil formation, thereby retarding the preferred thermodynamic pathway of cyclic compound formation (see scheme 12). 

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