Extrapolation summary

Dose-Response Curve (LOAEL-to-NOAEL Extrapolation) Summary AND Recommendations... 

Further detailed analyses of the ECA data have been extrapolated to USA national costs (Rice and Miller, 1998). It was calculated that the economic costs of mental disorders in 1990 in the USA totalled US 147.8 billion. Anxiety disorders were the most cosdy, amounting to 46.6 billion, just under a third of the total. Direct costs spent on mental health care totalled 67 billion, of which anxiety disorders accounted for only 11 billion (16.5%). Drug costs were 2191 million, of which anxiety disorders accounted for 1167 million—over half Morbidity costs—the value of goods and services not produced because of mental disorders — amounted to 63.1 billion, with anxiety disorders accounting for 34.2 billion, 54.2% of the total. This reflects the high prevalence of anxiety disorders in the community and the high associated rate of lost productivity. In contrast, patients with affective disorders appeared better able to function (Rice and Miller, 1995). In summary, anxiety disorders are common, disruptive and costly to society drug treatment is a substantial element of treatment costs (11%) compared with, say, schizophrenia (2.2%). 

In summary, practical experience with predicting the hydrolytic degradation of polyethylene terephthalate is an example of the use of Arrhenius extrapolation, a demonstration of the problems encountered when there are changes in the state of the polymer as the temperature is raised, and an example of the large variability in prediction of lifetime due to the logarithmic scale. 

Interspecies Extrapolation (Animal-to-Human) Summary and Recommendations... 

Summary of the current status of thermochemical estimates While all extrapolative methods have some disadvantages, there is no doubt that remarkably consistent values have been obtained through combining extrapolations from various different TC methods. This has led to the consolidation of lattice stabilities of a large number of elements (Dinsdale 1991). The driving force for such... 

In summary, the orthopyroxene geospeedometer is best applied to rocks that cooled rapidly so that Fe(Ml) can be measured to enough precision and extrapolation of experimental results is small. 

Available pharmacokinetic (PK) studies of medications with potential to treat pediatric anxiety disorders have been open studies that examine PK parameters and monitor adverse effects in children and adolescents. None of the pediatric PK studies described below were designed as dose finding studies, and none of the studies were able to describe a clear association between dose or exposure and specific adverse effect. However, pediatric PK data can be useful to guide dosing and adverse effect monitoring to the extent that the weight-adjusted PK parameters inform extrapolation based on comparable studies of adult PK. The following summary of PK studies is based on multiple-dose PK studies. 

The health effects associated with radon, as well as sources and mitigation measures, are discussed in detail in several National Research Council reports (1988, 1991), in the book edited by Nazaroff and Nero (1988), and in the International Commission on Radiological Protection Report (1994). Initial risk assessments were based on data from underground miners who were exposed to relatively high levels of radon and its progeny. However, there has been considerable controversy over the extrapolation to lower levels in homes [e.g., see summaries by Nazaroff and Teichman (1990) and Peto and Darby (1994)]. 

Figures 1 and 2 show the Engler boiling point characteristics at 1 mm. of mercury of the two oils and their fractions. A summary of the boiling point data is presented in Table II. These data were obtained in a specially designed vacuum Engler distillation apparatus at pressures ranging from 0.2 to 2.0 mm. of mercury all values were extrapolated to 1 mm. by means of a Brown-Coats chart (I).

In summary, extrapolation of reactions determined in homogeneous solutions to the soil system may not result in accurate predictions of possible products. Unanticipated abiotic reactions which occur during bioremediation may influence the products, causing altered degradative pathways of the contaminants. These pathways may be site specific because of differences in abiotic catalysts. Abiotic reactions may occur to both the parent compound or to intermediates formed during biotic alteration of the compound. Bioremediation efforts should include the possibility of site specific abiotic reactions. 

The crystalline inorganic monopropellants decompose directly from the solid to the vapor phase and are approximately described by the above mentioned theoretical work, in spite of the fact that the gas phase processes are simplified. However, the double-base propellants and other organic materials liquefy before vaporizing. In their combustion, so-called foam and fizz zones occur before the vapor phase processes. Much work has been done attempting to apply the conservation equations to the series of processes. This work forms the basis for the summary by Geckler (G3). It is the viewpoint of this author that too many parameters are determined empirically in this application of the theory, so that useful extrapolations are not possible. One must admire the manipulative skill of the early workers in this field and also their determination to formulate a complete theory. When and if the rate parameters become available, a useful theory will be developed with the aid of this early work. 

A typical chart for water content from this period is presented in Figure 4.21. In Figure 4.21 the water content chart at temperatures above the hydrate stability conditions is based primarily on the data of Olds et al. (1942) while the data of Skinner (1948) were the basis for extrapolations to temperatures below the hydrate formation point. A summary chart is given by McKetta and Wehe (1958). However, below the initial hydrate formation conditions, Figure 4.21 represents metastable values, as observed in gas field data by Records and Seely (1951). Kobayashi and Katz (1955) indicated that such concentration extrapolations across hydrate phase boundaries yield severe errors. 

In summary, in studies of chemical toxicity, pathways and rates of metabolism as well as effects resulting from toxicokinetic factors and receptor affinities are critical in the choice of the animal species and experimental design. Therefore it is important that the animal species chosen as a model for humans in safety evaluations metabolize the test chemical by the same routes as humans and, furthermore, that quantitative differences are considered in the interpretation of animal toxicity data. Risk assessment methods involving the extrapolation of toxic or carcinogenic potential of a chemical from one species to another must consider the metabolic and toxicokinetic characteristics of both species. 

A particularly appropriate method involves the use of different solvents (at least two), and the data are then extrapolated to infinite dilution (Schwager et al., 1979). There has also been the use of different temperatures for a particular solvent after which the data are extrapolated to room temperature (Speight et al., 1985 Speight, 1987). In this manner, different solvents are employed and the molecular weight of a petroleum fraction (particularly the asphaltenes) can be determined for which it can be assumed that there is little or no influence from any intermolecular forces. In summary, the molecular weight may be as close to the real value as possible. 

Estimated Exposures (pg/kg/day) to the General Population Based on Extrapolated Intake from Urinary Metabolites in 289 Individuals Measured by Blount et al. (2000), 170 5-6 Properties of Biomarkers Used as Examples in Chapter 5, 188 7-1 Summary of Major Points in Research Agenda, 252... 

Normative data using 40-min trials terminated after sleep onset have been published with extrapolations to estimate results if 20- and 30-min trials had been used. Figure 2 is a frequency histogram and Table 1 is a summary of parameters for normative MWT data gathered in the international, multisite cooperative... 

In man, the changes that result from the activation of different receptors have been inferred from clinical observation and from extrapolation from studies on animals. A summary of the interaction of morphine and a number of synthetic opioids on the three main receptor types is shown in Table 15.4. 

In summary, the overall error in microanalysis using GELS is a combination of the statistical error in the measurement of Ia (P, A) which for Poisson statistics (applicable in the case of EELS) is given by VIa, the errors in background fitting and extrapolation (-5%) above VlA, and the accuracy of the ionization cross-sections (theory -5-15%, experiments -2-5%). 

TABLE 1.4 (CONTINUED) Summary of types of extrapolation used in ecological risk assessment... 

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