Resolvation constant

J-Resolved Constant Time r Experiment for the Determination of the Phosphodiester Backbone Angles a and f 172... 

For the measurement of cross-correlated relaxation rates, there are mainly three methods that have been used in practice. In the /-resolved constant time experiment, the multiplet Hnes exhibiting differential relaxation are resolved by the f couplings, and the line width is translated into intensity in a constant time experiment (Fig. 7.19a,d). In the J-resolved real time experiment the line width of each multiplet line is measured instead (Fig. 7.19b, d). This experiment has been applied so far only for the measurement of... 

J-Resolved Constant Time Measurement of Cross-Correlated Relaxation Rates... 

Fig. 7.20 J-resolved constant r HN (CO)CA experiment for the measurement of cross-correlated relaxation rates, especially rcNH The experiment has two 90° (15N) pulses (shaded part) simulta-...

Fig. 7.21 Traces through co2 of the J-resolved constant r HN(CO)CA of rhodniin. The different multiplet patterns obviously indicate different geometries of the HN and Ha,Ca vectors for these residues.

As an example of the measurement of cross-correlated relaxation between CSA and dipolar couplings, we choose the J-resolved constant time experiment [30] (Fig. 7.26 a) that measures the cross-correlated relaxation of 1H,13C-dipolar coupling and 31P-chemical shift anisotropy to determine the phosphodiester backbone angles a and in RNA. Since 31P is not bound to NMR-active nuclei, NOE information for the backbone of RNA is sparse, and vicinal scalar coupling constants cannot be exploited. The cross-correlated relaxation rates can be obtained from the relative scaling (shown schematically in Fig. 7.19d) of the two submultiplet intensities derived from an H-coupled constant time spectrum of 13C,31P double- and zero-quantum coherence [DQC (double-quantum coherence) and ZQC (zero-quantum coherence), respectively]. These traces are shown in Fig. 7.26c. The desired cross-correlated relaxation rate can be extracted from the intensities of the cross peaks according to ... 

Fig. 7.26 J-resolved constant r C,H-HSQC experiment (a) to measure the cross-correlated relaxation rates in RNA with a geometry given in b.

A similar approach has been developed for calculation of solvate shell composition Na and F in the mixed solvent formed by the components with close values of permittivity. Such solvent selection permits us to eliminate the permittivity effect on solvation equilibrium. Resolvation constants have been determined from the calorimetric study. The composition of anions solvate complex has been determined from experimental data of electrolyte BU4NI assuming lack of the cation specific solvation. Experimental data are presented in Figure 9.10. 

Data presented in Figure 9.13 contain information on the composition of solvate shell as a function of molar fraction of water in the mixed solvent Fl20-other solvents. Monograph contains collection of data on resolvation constants of the ions in the mixed solvents. 

The above presented dependencies of the composition of solvate shell on the mixed solvent composition as well as resolvation constants permit calculation of the solvate composition by varying solvent composition. The dependence of resolvation constants on the permittivity of the solvent is discussed in the example of the proton resolvation process. 

For the calculation of resolvation constant, one must determine the experimental constant of HA association in the mixed solvent and determine independently Kf and K . 

The concept of solvent effect on the proton resolvation process was confirmed by quantum chemical calculations. Above phenomena determine the dependence of resolvation constant on physical and chemical properties. 

The last equation permits to calculate value for the solvent of fixed composition and Xg determination at certain composition of the solvate complexes p and q and resolvation constant K s. 

Equation [9.9 Ic] developed for the ideal solution E-A-B permits us to establish the relationship between the composition of mixed solvent Xg and the solvate shell composition x. For the special case of equimolar solvates, the expression of resolvation constant is written in the form ... 

The reference stack algorithm efficiently resolves constant and variable propagation, conditional assignment to variables, and multiple assignment to variables. By using the reference stack, many of the control steps that are traditionally needed to implement assignment to variables can be eliminated. This leads to an improvement in the latency of the resulting hardware. 

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