Comprehensive assay

To obtain the necessary information, two different analytical schemes are commonly used. These are (1) an inspection assay and (2) a comprehensive assay. 

Inspection assays usually involve determination of several key bulk properties of petroleum (e.g., API gravity, sulfur content, pour point, and distillation range) as a means of determining whether major changes in characteristics have occurred since the last comprehensive assay was performed. 

On the other hand, the comprehensive (or full) assay is more complex (as well as time-consuming and costly) and is usually only performed only when a new field comes on stream, or when the inspection assay indicates that significant changes in the composition of the crude oil have occurred. Except for these circumstances, a comprehensive assay of a particular crude oil stream may not (unfortunately) be updated for several years. 

Devarajan, K, Ma, H, and Peterson, J.R. (2011) Comprehensive assay of kinase catalytic activity reveals features of kinase selectivity. Nature Biotechnology, 29, 1039-1045. 

To obtain the desired information, two different analytical schemes are commonly used, namely, an inspection assay and a comprehensive assay. Inspection assays usually involve determination of a few key whole crude oil properties such as API gravity, sulfur content, and pour point—principally as a means of determining if major changes in a crude oil stream s characteristics have occurred since the last comprehensive assay was performed. Additional analyses may be performed to help ensure that the cargo or shipment received is that which is expected to ascertain the quantity of impurities such as salt, sediment, and water and to provide other critical refinery-specific information. Inspection assays are routinely performed on all shipments received at a refinery. The comprehensive assay, on the other hand, is complex, costly, and time-consuming and is normally performed only when a new field comes on stream, or when the inspection assay indicates that significant changes in the stream s composition have occurred. Except for these circumstances, a comprehensive assay of a particular crude oil stream may not be updated for several years. 

The inspection assay tests discussed above are undoubtedly not exhaustive, but are the ones most commonly used. These tests will provide the refiner with data on the impurities present and a general idea of the products that may be recoverable. However, they will not provide the data essential to determining whether a given crude oil or blend of crude oils will yield an economically attractive product slate. This requires that a comprehensive assay be performed. 

In addition to the whole crude oil tests performed as part of the inspection assay, a comprehensive or full assay requires that the crude he fractionally distilled and the fractions characterized by appropriate tests. This is necessary so that the refiner can assess the quantity and quality of products recoverable from a given crude oil and determine if that product slate economically satisfies the market requirements of a particular refineiy. Refiners tailor a comprehensive assay to their individual needs, and the number of cuts or fractions taken may vary from as few as 4 to as many as 24. The following eight fractions will provide the basis for a moderately thorough evaluation ... 

Few analgesics such as morphine and related opiates have been prohibited in human sports, and all members of the class of analgesic therapeutics are not allowed for the treatment of competing animals. Hence, various methods using HPLC were established to determine the presence of these compounds in urine and blood samples, and comprehensive assays enabled the detection of 10-100 ng/mL of analytes such as morphine, ketoprofen, naproxen,... 

An assay varies in depth and complexity depending upon the crude oil type and its final use. The assay can be an inspection assay or comprehensive assay. There are various types of assays, which vary considerably in the amount of determined experimental information ... 

The following brief account identifies only major groups of herbicides not mentioned elsewhere in the text, and is far from comprehensive. Their mode of action is only dealt with in a superficial way. From an ecotoxicological point of view, there has not been as much concern about their sublethal effects upon plants as there has been in the case of mammals, and there has not been a strong interest in the development of biomarker assays to establish their effects. The major concern has been whether weeds, or nontarget plants, have been removed following herbicide application—a rather easy matter to establish as plants are fairly sedentary. For a more detailed account of herbicide chemistry and biochemistry, see Hassall (1990). 

The yeast reporter gene assays not only assess for the interaction of the chemical with the hormone receptor, but also the ability of that receptor-chemical ligand interaction to activate the hormone DNA response element. It should be realized, however, that most of these systems have been developed with human and mammalian hormone receptors and differences in ligand potencies can occur between different animal species. A comprehensive review of in vitro assays for measuring estrogenic activity, and some of the issues of comparability, is provided by Zacharewski (1997). 

Schnurr B, Ahrens T, Regenass U (2006) Optical assays in drug discovery In Taylor JB, Triggle DJ (eds) Comprehensive medicinal chemistry II. Elsevier, Oxford, Sect 3.27... 

Enzymatic reactions are influenced by a variety of solution conditions that must be well controlled in HTS assays. Buffer components, pH, ionic strength, solvent polarity, viscosity, and temperature can all influence the initial velocity and the interactions of enzymes with substrate and inhibitor molecules. Space does not permit a comprehensive discussion of these factors, but a more detailed presentation can be found in the text by Copeland (2000). Here we simply make the recommendation that all of these solution conditions be optimized in the course of assay development. It is worth noting that there can be differences in optimal conditions for enzyme stability and enzyme activity. For example, the initial velocity may be greatest at 37°C and pH 5.0, but one may find that the enzyme denatures during the course of the assay time under these conditions. In situations like this one must experimentally determine the best compromise between reaction rate and protein stability. Again, a more detailed discussion of this issue, and methods for diagnosing enzyme denaturation during reaction can be found in Copeland (2000). 

In conclusion, there are several drawbacks to the use of Caco-2 cells in studies of active drug transport. Despite these drawbacks, we note that a recent comprehensive study comparing various P-glycoprotein drug efflux assays in drug discovery came to the conclusion that the Caco-2 transport assay is the method of choice, since it displays a biased responsiveness towards compounds with low or moderate permeability - in other words, towards compounds whose intestinal permeability is most likely to be significantly affected by drug efflux mechanisms [101]. 

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