Total parameters

Two issues present themselves when the question of PB-PK model validation is raised. The first issue is the accuracy with which the model predicts actual drug concentrations. The actual concentration-time data have most likely been used to estimate certain total parameters. Quantitative assessment, via goodness-of-fit tests, should be done to assess the accuracy of the model predictions. Too often, model acceptance is based on subjective evaluation of graphical comparisons of observed and predicted concentration values. 

Total Parameters as a Tool for the Evaluation of the Load of Xenobiotics in the Environment... 

Biochemical oxygen demand (BOD) is arguably the oldest total parameter used for the characterization of water quality. It was introduced in the first decade of the twentieth century as a test for the organic pollution of rivers. BOD is the amount of oxygen in mg L 1 required for the oxidation of the organic matter contained in water by biological action under standardized test conditions (usually a temperature of 20°C and an incubation time of 5 days).8 9 The test is often used to evaluate the efficiency of wastewater treatment processes. 

Table 10.3 is followed by a brief literature review covering mostly research published in the last decade. The review is not intended to be comprehensive—its main goal is to illustrate that total parameters are still valuable tools in environmental analytics, in spite of the rapid development of ever more powerful chemical speciation methods and techniques. 

Examples of Total Parameters Used in Environmental Analysis and Monitoring6... 

Determination of total parameters is an example of activities classified as group speciation. Taking into account the sheer number and diversity of different chemicals that may be present in environmental samples, determination of total parameters could be an attractive alternative to full chemical speciation, especially for the initial screening of samples. Samples for which the value of a given total parameter exceeds prescribed limits can then be further analyzed using more advanced methods. Overall, group speciation can save both time and money in the characterization of environmental samples. 

The volume of the hyperellipsoid represents the total parameter uncertainty, so a minimization of it is a valid goal. The volume can be determined by... 

Analytical method Measured characteristics Total parameters Typical preparation Required sample... 

It is frequently observed in analytical practice that the phenol index as a total parameter gives positive measured values whereas the analysis for... 

Using Scott s extension [23] of the Mory-Huggins theory, it was shown [24] that the total parameter of interaction between the volatile substance and the binary stationary phase, X-uist, is given by ... 

Correlations between log(D) and E , and between log(D) and CED were good. These results suggest that gas diffusivity is affected by the cohesive forces of polymers. Toi et al. and we have reported a correlation between log(D) and CED independently(9,35-37). Jia and Xu have reported correlations between gas permeability and a parameter which included contributions from both CED and Vf(38). CED depends on the square of the solubility parameter, which we treat as a total parameter with dispersive, polar, and hydrogen-bonding contributions. Van Krevelen(39) has indicated that a simple correlation between dielectric constant, 6, and CED is observed for polymers. This notion is expressed by Equation 11. 

The composition is a total parameter, not a local one. The homogenity is not a kinetic factor of the mixture. Also, the stoichiometric corrqxrsition of each elementary cell is taken eqital to the average composition, and the powder is represented by a collection of iderrtical cells the calculated fractional extent for a cell is then identical to that of the total mixture and the rate is separable. 

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