Correlations moderate

Phenobarbitone has a long half-life of about 3 days (M7) and plasma levels correlate moderately well with the daily dose (B4, B32, S30). A therapeutic range (Table 2) of 8-21 ju.g/ml has been described (S30), and severe toxic symptoms are rarely encountered in association with plasma levels below 50/tg/ml (Lll). 

D = (1.8 0.6) x 10 12m2s 1. The encounter distance was estimated to be 1.32 nm, which, when used in the Stokes—Einstein relation for the mutual diffusion coefficient, eqn. (28), givesD as (1.1 0.03) x 10 I2m2 s-1, in reasonable agreement with the estimate from fitting experimental and theoretical decay curves (mentioned above). The germinate pair recombination probability at long times was measured and its increase correlates moderately well with T1/2/rj as noted for other systems (see Sect. 3.1) but was concave upwards (see ref. 22). 

A number of physical methods have found support in molecular orbital theory, or have provided evidence that the deductions of molecular orbital theory have some experimental basis. Electron affinities correlate moderately well with the calculated energies of the LUMO, ionisation potentials correlate moderately well with the calculated energies of the HOMO, and spectroscopic methods reveal features that support molecular orbital theory. 

In another example, real-time polymerase chain reaction (RT-PCR) was used to determine expression levels of the 48 known human ABC-type transporters in the NCI-60 cell lines, and these levels were correlated with sensitivity to 1429 candidate anticancer drugs (149, 150). Patterns of expression correlated moderately well with tissue of origin and were independent of sequence homology among... 

Carbon monoxide chemisorption was measured at 25 °C on all catalysts tested. The results were used in calculations of turnover numbers, assuming only rhodium metal atoms chemisorbed CO. While this assumption is naive and probably incorrect (10), results correlated moderately well with rhodium particle size determinations by transmission electron microscopy. 

The nitrogen resonances correlate moderately well with the methyl 13... 

Measures of hair lead and blood lead have been demonstrated to correlate moderately well (r = 0.7-0.8) in situations where the exposure is high and relatively constant for example in occupationally exposed adults. In children exposed to lower environmental lead levels the correlations are much lower, at around 0.1-0.3. 

Comprehensive data collection for more than 6000 binary and multicomponent mixtures at moderate pressures. Data correlation and consistency tests are given for each data set. 

For the acetone-methanol data of Othmer, the correlation coefficient is -0.678, indicating a moderate degree of correlation between the two van Laar parameters. The elongated confidence ellipses shown in Figure 2 further emphasize this correlation. 

VPLQFT is a computer program for correlating binary vapor-liquid equilibrium (VLE) data at low to moderate pressures. For such binary mixtures, the truncated virial equation of state is used to correct for vapor-phase nonidealities, except for mixtures containing organic acids where the "chemical" theory is used. The Hayden-0 Connell (1975) correlation gives either the second virial coefficients or the dimerization equilibrium constants, as required. 

The low MW power levels conuuonly employed in TREPR spectroscopy do not require any precautions to avoid detector overload and, therefore, the fiill time development of the transient magnetization is obtained undiminished by any MW detection deadtime. (3) Standard CW EPR equipment can be used for TREPR requiring only moderate efforts to adapt the MW detection part of the spectrometer for the observation of the transient response to a pulsed light excitation with high time resolution. (4) TREPR spectroscopy proved to be a suitable teclmique for observing a variety of spin coherence phenomena, such as transient nutations [16], quantum beats [17] and nuclear modulations [18], that have been usefi.il to interpret EPR data on light-mduced spm-correlated radical pairs. 

For these reasons, in the MCSCF method the number of CSFs is usually kept to a small to moderate number (e.g. a few to several thousand) chosen to describe essential correlations (i.e. configuration crossings, near degeneracies, proper dissociation, etc, all of which are often tenned non-dynamicaI correlations) and important dynamical correlations (those electron-pair correlations of angular, radial, left-right, etc nature that are important when low-lying virtual orbitals are present). 

In the CI method, one usually attempts to realize a high-level treatment of electron correlation. A set of orthonormal molecular orbitals are first obtained from an SCF or MCSCF calculation (usually involving a small to moderate list of CSFs). The FCAO-MO... 

The disadvantage of ah initio methods is that they are expensive. These methods often take enormous amounts of computer CPU time, memory, and disk space. The HF method scales as N, where N is the number of basis functions. This means that a calculation twice as big takes 16 times as long (2" ) to complete. Correlated calculations often scale much worse than this. In practice, extremely accurate solutions are only obtainable when the molecule contains a dozen electrons or less. However, results with an accuracy rivaling that of many experimental techniques can be obtained for moderate-size organic molecules. The minimally correlated methods, such as MP2 and GVB, are often used when correlation is important to the description of large molecules. 

Because geometry optimization is so much more time-consuming than a single geometry calculation, it is common to use different levels of theory for the optimization and computing hnal results. For example, an ah initio method with a moderate-size basis set and minimal correlation may be used for opti-... 

Acid amide herbicides are nonionic and moderately retained by soils. The sorption of several acid amide herbicides has been investigated (369). Acetochlor [34256-82-1] is sorbed more than either alachlor or metolachlor, which are similarly sorbed by a variety of soils. Sorption of all the herbicides is well correlated to soil organic matter content. In a field lysimeter study, metolachlor has been found to be more mobile and persistent than alachlor (370) diphenamid [957-51-7] and napropamide [15299-99-2] have been found to be more readily leached (356). 

Models of Pha.se Monideahty. The correlation and prediction of phase equiUbria at low (near-vacuum) to moderate (several hundred kPa) pressures is typically based on a form of equation 19. The key is the degree to which the various parameters for phase nonideaUty are known or can be estimated. 

Correlation Methods Vapor pressure is correlated as a function of temperature by numerous methods mainly derived from the Clapeyron equation discussed in the section on enthalpy of vaporization. The classic simple equation used for correlation of low to moderate vapor pressures is the Antoine S equation (2-27). 

Correlation Methods Vapor densities are not correlated as functions of temperature alone, as pressure and temperature are both important. At high temperatures and very low pressures, the ideal gas law can be applied whde at moderate temperature and low pressure, vapor density is usually correlated by the virial equation. Both methods will be discussed later. 

Data Reduction Correlations for G and the activity coefficients are based on X T.E data taken at low to moderate pressures. The ASOG and UNIFAC group-contribution methods depend for validity on parameters evaluated from a large base of such data. The process... 

Tyn-Calus This correlation requires data in the form of molar volumes and parachors = ViCp (a property which, over moderate temperature ranges, is nearly constant), measured at the same temperature (not necessarily the temperature of interest). The parachors for the components may also be evaluated at different temperatures from each other. Quale has compiled values of fj for many chemicals. Group contribution methods are available for estimation purposes (Reid et al.). The following suggestions were made by Reid et al. The correlation is constrained to cases in which fig < 30 cP. If the solute is water or if the solute is an organic acid and the solvent is not water or a short-chain alcohol, dimerization of the solute A should be assumed for purposes of estimating its volume and parachor. For example, the appropriate values for water as solute at 25°C are = 37.4 cmVmol and yn = 105.2 cm g Vs mol. Finally, if the solute is nonpolar, the solvent volume and parachor should be multiplied by 8 Ig. 

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