Stabilization/destabilization

The larger the charge and the closer the dipole is to t charge, the greater will be the stabilization ( destabilization). 

In all of the above, the activating, directive and stabilizing destabilizing effects are similar in principle to those in the acyclic systems. However, the magnitude of these effects per se, or in conjunction with other characteristics of the systems in point, are considerably different and, consequently, the ultimate chemical results may be different. 

The in-phase (out-of-phase) combined orbitals are stabilized (destabilized) and bonding (antibonding)... 

In order to determine where the energy differences stem from, the effects of the individual residues on the stabilization(destabilization) of the QM subsystem were analyzed as explained in Ref. [33], These results are shown in Tables 3-3 and 3-4,... 

At the symposium on which this book is based, the various authors presented papers on the general topic of polymer adsorption and particle stabilization/destabilization. In this volume both aqueous and nonaqueous systems are included, comprising work on both natural and synthetic polymers. Together the chapters constitute a comprehensive update of research in progress on these topics and provide broad coverage of both experimental and theoretical aspects. 

Chemical modification of proteins has been extensively studied over the years to identify which amino acids are involved in catalysis. Much less work has been carried out on its influence on enzyme stability. Chemical modification of proteins may yield stabilization, destabilization or no effect at all. Martinek and Berezin (1978) reported the dependence of the thermostability of chymotrypsin on the degree of alkylation of its amino groups up to 30% alkylation the stability rose slightly at 90% substitution stability increased markedly, with a maximum (110-fold) at 95% stability fell to nearly initial values when 100% amino groups were modified. (With these modifications, the optimum pH of the errzyme can change and one must therefore be cautious in comparing two different... 

For geminal nuclei A and X, the Pauli principle favors a parallel precession (Fig. 1.11 (b)). A stabilization-destabilization pattern opposite to the directly bonded and vicinal nuclei arises (Fig. 1.11(a)), and the coupling constant is defined to be negative (Ax < 0). There are experimental techniques to determine the relative sign of coupling constants [5]. 

Then z-scores for all mutant objects are calculated and the portion of stabilizing, destabilizing, and neutral mutations is recorded. These values are finally sent to the screen or to a file, if a filename was given as additional argument, analyse mutability Fd 9... 

This command first derives 103 mutants from the object Fd by substituting all amino acids in the specified positions with randomly chosen ones. For each mutant, z-scores are calculated and compared to the Fd z-scores. Since 1001 z-scores have to be determined, this calculation lasts about 5.5 h. Results are written to two files Fd epil. sip contains all the z-scores, and Fd epil. nrm holds a summary of the number of stabilized, destabilized, and neutral mutants within the sample population (Figure 11.8). 

Table 26 The effect of product/reactant stabilizing/destabilizing factors on AG and ka... 

A donor substituent at position 4 or 6 will favor the reaction and an attractor similarly placed will hinder it. Conversely, an attractor (donor) at position 1 stabilizes (destabilizes) the enolate fragment. As atoms 2 and 5 bear no charge, the electronic character of the substituent has little consequence. By analogy with the Cope reaction, we expect that a substituent at these positions also accelerates the Claisen reaction. 

The role of surfactants in stabilization/destabilization of foam (air/liquid dispersions) is similar to that for emulsions. This is due to the fact that foam stability/instability is determined by the surface forces operative in liquid films between air bubbles. In many industrial applications, it is essential to stabilize foams against collapse, e.g., with many food products, foam in beer, fire-fighting foam, and polyurethane foams that are used for furniture and insulation. In other applications, it is essential to have an effective way of breaking the foam, e.g., in distillation... 

Anderson, M., Brooker, B.E. 1988. Dairy foams. In Advances in Food Emulsions and Foams (E. Dickinson, G. Stainsby, eds.), pp. 221-256, Elsevier Applied Science, London,. Anderson, M., Brooker, B.E., Needs, E.C. 1987. The role of proteins in the stabilization/ destabilization of dairy foams. In Food Emulsions and Foams (E. Dickinson, ed.), pp. 100-109, Royal Society of Chemistry, London. 

The stability of emulsion and foam films have also been found dependent upon the micellar microstructure within the film. Electrolyte concentration, and surfactant type and concentration have been shown to directly influence this microstructure stabilizing mechanism. The effect of oil solubilization has also been discussed. The preceding stabilizing/destabilizing mechanisms for three phase foam systems have been shown to predict the effectiveness of aqueous foam systems for displacing oil in enhanced oil recovery experiments in Berea Sandstone cores. 

Introducing a phosphorous ligand with a strong (weak) LF ligand should cause both stabilization (destabilization) of the rhenium du orbitals and destabilization (stabilization) of the rhenium da orbitals, it does only a small effect on the bipyridine n orbital. 

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