Comparability testing defined

Therefore, let us start by proposing a definition, one that can at least serve as a basis for our own discussions. Let us define linearity as The property of data comparing test results to actual concentrations, such that a straight line provides as good a fit (using the least-squares criterion) as any other mathematical function. ... 

Once a suitable working level of enzyme has been established, and for simple comparative tests, it is sufficient to record the AA after 10 min incubation and use this as a measure of activity. In this case, a unit ofDPO activity may be arbitrarily defined as that concentration of enzyme giving a AA of 0.001 AU/min. 

FEG-SEM of crack-tip deformation in a [3 nucleated CT specimen and Fig. 23 shows the corresponding TEM images. These confirm deformation to be less localised than in a spherulites at comparable test speeds, with diffuse regions of cavitation and lamellar shear coexisting with relatively well-defined crazes. The craze structures themselves are nevertheless similar to those in a-iPP. 

Method transfer is loosely defined as a process that qualifies a laboratory to use a test procedure or analytical method. According to this definition, any and all means of having a laboratory qualified would meet the criteria for transfer. The most common variations of method transfer are comparative testing, covalidation between two laboratories or sites, complete or partial method validation or revalidation, and the omission of formal transfer processes, sometimes termed the transfer waiver. ... 

Obtaining valid data for ROC analysis requires attention to the following important steps (1) define carefully the specific clinical question to be addressed (2) choose subjects who are representative of the population to which the test is ultimately to be applied (3) perform all tests being evaluated on all subjects (4) determine the "true diagnosis by rigorous and complete means independent of the test(s) being studied and (5) evaluate and compare test performance at all decision levels using ROC curves. 

Preparation of Test Samples. Almost all properties of coatings depend on the layer thickness of the film. To obtain reproducible comparable test results, measurements must be made on carefully prepared films with a defined layer thickness. Films may be either free or applied to a substrate. In some cases film properties are also measured on films with different thicknesses. 

Examples of comparative gel tests with a hydrolyzed polyacrylamide are presented below. The screening experiment discussed above indicated that polymer molecular weight and salinity are important in the gel reaction. The comparative tests are used to define the magnitude of these variable effects. In addition, the results demonstrate the usefulness of the simple beaker tests described earlier. 

The freshwater micro-crustacean Daphnia magna is the most often used organism for the standardised methods OECD 202 [45] and DIN 38412-30 [50]. For a short-term test, five animals of a defined physiological state are added to about 25 cm of an aqueous sample or its dilutions. The survival of the Daphnia is observed over a period of 48 hours and compared with the survivors of the control test. For a long-term test the same set up is used but the animals are fed with algae and exposed over a period of up to four weeks. The number of young Daphnia (due to reproduction) is counted and compared with those of the control test. Defined concentrations of potassium chromate are used as a positive reference to validate the required sensitivity of the animals. 

For the assessment of the effects, a test board was positioned behind the test vehicle in the field of vision of the CMS and mirror in order to receive a comparable and defined image. Two radio units of the brand Topcom with a frequency of 446 MHz were used as the source of the electromagnetic radiation, which sent out a call close to the camera, monitor and control device. In addition, a mobile phone (Sony Experia Sola) receiving a call, was placed in the same position. 

The CMS monitors are based on LCD technology (liquid crystal display). This means that they contain liquid crystals in the displays which operate with severe limitations in cold temperatures as the liquid crystals become sluggish due to the cold, which in turn results in the image loading more slowly. To test the CMS in extreme cold, the test vehicle was cooled in a climate chamber to a temperature of -20 °C and conditioned for one night. A test board was positioned as a reference on to a presentation wall, in order to receive a comparable and defined image. 

Comparative testing is the most common form of method transfer. It involves two (or more) laboratories testing identical, well-defined samples. Success of the transfer is based on a preapproved protocol that includes the acceptance criteria, including acceptable variability. 

A meaningful way to compare tests at different scales or with different initial conditions is on the basis of the measured pressurization efficiency, r. This is defined as... 

The standards for tests, which are cited in reference to the standards for characteristics. In order for a client and his supplier to compare their results during a commercial transaction, it is important that their laboratories rigorously follow the same operating procedures. The procedures are thus precisely defined in the standards. 

A specification or standard for product characteristics is valid only if it is matched with references to well defined and recognized test methods, such that quality control tests conducted by the parties involved —client and supplier, for example— are comparable even if they are performed at different locations. 

The most direct test is to compare the BET area with the geometrical area of the solid. Unfortunately, comparisons of this kind are relatively rare on account of experimental difficulties. The choices are to work with, say, single crystals having a well defined surface, when techniques of quite extraordinary sensitivity will be needed for measurement of the adsorption or, to obtain a larger surface area by use of thin sheets, narrow rods or small spheres, and run the risk that the surface will not be truly smooth so that the actual area will exceed the geometrical area. 

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