Conformation correction factor

The chemical shifts of sp -hybridized carbon atoms in the vicinity of double bonds can be estimated using the additivity rule given on page 78. The conformational correction factors, K, for y-substituents of cis- vs. trans-disubstituted alkenes differ by 6 ppm because the relative position of these substituents is fixed by the double bond. 

Competitive antagonists affinity of, 261-264 description of, 75 IC50 correction factors for, 223 Schild analysis, 261-264 Concentration-dependent antagonism, 99 Concentration-response curve, 13 Confidence intervals, 228-229 Conformations, 13-14 Constitutive activity of receptors description of, 49—51 receptor density and, 56 Schild analysis, 108-111 Context-dependent biological effect, 188 Correction factors, 211-213, 223 Correlational research, 231 CP320626, 128... 

Reflection intensity in the SAED negatives was measured with a microdensitometer. The refinement of the structure analysis was performed by the least square method over the intensity data (25 reflections) thus obtained. A PPX single-crystal is a mosaic crystal which gives an "N-pattem". Therefore we used the 1/d hko as the Lorentz correction factor [28], where d hko is the (hkO) spacing of the crystal. In this case, the reliability factor R was 31%, and the isotropic temperature factor B was 0.076nm. The molecular conformation of the P-form took after that of the P-form since R was minimized with this conformation benzene rings are perpendicular to the trans-zigzag plane of -CH2-CH2-. 

The empirical correction factors 4> (calculated on assumption that for all networks swollen in pure water % from Eq. (6) should be 0.48) change between 0.05 and 0.3 (see Ref. [48] for salt I the data are in Fig. 8). Generally, we can say that the effect of the positive charge on the formation and extent of transition is 5 to 10 times smaller than the effect of MNa. There are probably several reasons for the low value of (a) positive charges are localized at a larger distance from the main chain (smaller influence on the chain conformation) (b) due to the... 

Analysis of the microwave spectrum of piperidine and of A-deuteropiper-idine suggests that the strongest Q-branch series together with the associated R-branch lines arise from the N-H-axial conformer.144 From this absorption and from a weaker series of Q branches, /eq//aj (the relative intensities of the type-A lines of /V-Hcq and N-Hax conformers corrected for the frequency factor) was estimated as 1/6 at — 34°C. This ratio is related to AE = En Hax - jv-Hcq by the expression... 

This result must of course be correted for small values of XQpt using the correction factor mentioned above. For feedwater heaters, a similar result is obtained by expanding the logarithm in Eqn. (15) to obtain a value of Oy = (y-l) /2y which needs another correction factor to conform to Eqn. (15) exactly. This merely introduces a factor of two into Eqn. (A2) so that for feed-water heaters, the corresponding basic results is... 

A special increment system for methyl-substituted cycloalkanes requires for each substituent a positional parameter which is different for axial and equatorial substitution. Furthermore, correction factors for vicinal methyl pairs have to be included . This increment system is presented in Table 5 along with an example of its use. Conformational... 

These problems illustrate the danger of quantitatively extrapolating notions of conformational analysis based on very simple systems such as butane to more complicated structures. This caveat is true both in thinking about structures in general and in applying group increments correction factors. The correction factors are the best possible estimate, but we must be wary of their use. Another important example of this concerns -pentane and related structures, which we consider next. 

In the case of laminar liquid flow with Reynolds numbers of ReL < 5, the liquid holdup hL can be described reasonably well using Mersmann and Deixler s [44] method, with 85% of the experimental values verified with an accuracy of S(hL) < 20%, Fig. 4-11 a. Figure 4-11b shows deviations of 0— +50%, in which the hL,exp values are compared to the values calculated acc. to Berner and KaHs [12], see Eq. (4-20). Hence, the use of a correction factor of 3/4 in Eq. (4-20) has proved to be useful, as it leads to a considerably better conformance between the calculated and experimental values, see Table 4-3, with the exception of some experimental data taken at extremely low liquid loads, which cannot be sufficiently described by any of the methods available. 

Hart (1978) has applied this proc ure to a conformational analysis of 2, 3 -cyclic cytidine monophosphate (cCMP), as well as 3 - and 5 -adenosine monophosphate (3 -AMP and 5 -AMP). Because proton chemical-shift dispersion is limited at the fields used for these experiments (2.1 T), proton irradiation power was less than optimum to minimize multiple irradiation, and correction factors were applied to the computed enhancement profiles before comparing them to the experiment profiles. The corrections also take into account the observation that total NOEs are less than the theoretical maximum of 1.24. 

In general, the R factor is between 0.15 and 0.20 for a well-determined protein structure. The residual difference rarely is due to large errors in the model of the protein molecule, but rather it is an inevitable consequence of errors and imperfections in the data. These derive from various sources, including slight variations in conformation of the protein molecules and inaccurate corrections both for the presence of solvent and for differences in the orientation of the microcrystals from which the crystal is built. This means that the final model represents an average of molecules that are slightly different both in conformation and orientation, and not surprisingly the model never corresponds precisely to the actual crystal. 

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