Subject quantitative composition

In general, the risks of reaching an inappropriate biowaiver decision need to be more critically evaluated when the extent of absorption is lower (especially if fgbj < 50%), if the sites of absorption are restricted to the proximal regions in the gastrointestinal tract and/or if the mechanism of absorption is subject to induction/competition. If any of these cases apply, the excipients used will also need to be scrutinized carefully in terms of both qualitative and quantitative composition - the greater the deviation from the comparator composition, the greater the risk of an inappropriate biowaiver decision. 

In less severe cases of diarrhea and in other diseases of less severe character the findings of the quantitative composition of the fractions are normal or only insignificantly different from normal values. Significant, however, are the qualitative changes. During the disease the values of the denaturation capability can become still less favorable, and children who have overcome the disease are released from the clinic with a deviation of the quality of proteins still discernible. The persistence of these qualitative deviations determines objectively the time of reconvalescence, which formerly used to be established on the basis of anamnestic data and subjective experience of the physician. 

Comparison of the data on the qualitative and quantitative composition of the fecal microflora of the two groups of subjects showed a significant increase on the number of bifidobacteria. Gram-positive anaerobic cocci, coliforms and total aerobes in the feces of the treated patients (Figure 1). However, these alterations do not represent a substantial modification of the intestinal microflora composition. 

The iron-carbon system has been investigated in our laboratory. The powders were subjected to thermal treatment and next they were investigated by the potentiometric method in powder electrodes, and by the metallographic method using grinds and corrosions of the powder in shellac. Both the carbon content and the structure of the system had an influence on the rates of change and the value of the powder electrode potential in aqueous solution of potassium sulphate. The potentiometric measurements enabled us to define the structure when the quantitative composition of an alloy was known. 

In a modern industrialised society the analytical chemist has a very important role to play. Thus most manufacturing industries rely upon both qualitative and quantitative chemical analysis to ensure that the raw materials used meet certain specifications, and also to check the quality of the final product. The examination of raw materials is carried out to ensure that there are no unusual substances present which might be deleterious to the manufacturing process or appear as a harmful impurity in the final product. Further, since the value of the raw material may be governed by the amount of the required ingredient which it contains, a quantitative analysis is performed to establish the proportion of the essential component this procedure is often referred to as assaying. The final manufactured product is subject to quality control to ensure that its essential components are present within a pre-determined range of composition, whilst impurities do not exceed certain specified limits. The semiconductor industry is an example of an industry whose very existence is dependent upon very accurate determination of substances present in extremely minute quantities. 

Perhaps the most obvious method of studying kinetic systems is to periodically withdraw samples from the system and to subject them to chemical analysis. When the sample is withdrawn, however, one is immediately faced with a problem. The reaction will proceed just as well in the test sample as it will in the original reaction medium. Since the analysis will require a certain amount of time, regardless of the technique used, it is evident that if one is to obtain a true measurement of the system composition at the time the sample was taken, the reaction must somehow be quenched or inhibited at the moment the sample is taken. The quenching process may involve sudden cooling to stop the reaction, or it may consist of elimination of one of the reactants. In the latter case, the concentration of a reactant may be reduced rapidly by precipitation or by fast quantitative reaction with another material that is added to the sample mixture. This material may then be back-titrated. For example, reactions between iodine and various reducing agents can be quenched by addition of a suitably buffered arsenite solution. 

During the latter part of the nineteenth century and the early years of the twentieth century, there was considerable controversy over the composition of chemical compounds—were compounds strictly stoichiometric, with an immutable composition, or could the composition vary. Indeed, at the turn of the twentieth century, even the existence of atoms was a subject of debate. The principal techniques involved at this epoch were accurate quantitative chemical analysis and metallo-graphic studies of phase equilibria. The advent of X-ray diffraction studies effectively resolved the problem, and the experimental evidence for composition ranges of many solids became incontestable. 

The application of the SVD technique provides a measure of the controllability properties of a given d mamic system. More than a quantitative measure, SVD should provide a suitable basis for the comparison of the theoretical control properties among the thermally coupled sequences under consideration. To prepare the information needed for such test, each of the product streams of each of the thermally coupled systems was disturbed with a step change in product composition and the corresponding d3mamic responses were obtained. A transfer function matrix relating the product compositions to the intended manipulated variables was then constructed for each case. The transfer function matrix can be subjected to SVD ... 

Our current estimate for the quantitative mineral composition of the entire oil shale sample based on all 10 clusters Is presented In Table VII. These estimates are consistent with the qualitative XRD results of Table I. Because they are subject to several sources of uncertainty, It Is Impractical to assign error bounds at this time. These Include uncertainty In values of chemical elements for test vectors, problems In Identifying minor mineral components In the clusters, uncertainty In the relative concentrations of each element, and uncertainty In the organic content of each sample. 

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