Comparisons with other tests

In Table 15.2.2.3 the results of eomparisons among these tests are summarized. The data from these 6 determinations were plotted, one assay versus another assay, the regression eoeffieient noted and the eorrelation eoeffieient ealeulated. The Rhizobium assay was the most sensitive for 12 of 33 ehemieals. The Mierotox assay was most sensitive for 6 of the eompounds. The IC50 assay was most sensitive for 6 of the eompounds. The Daphnia test was most sensitive to 10 of the eompounds. The average values for the toxieity of the ehemieals was lowest for the IC50, but then it was also the test with the fewest values in-eluded. 

The data for rats, Daphnia, HLD is fiom CaUeja et al., 1994. The data for IC50 is fiom Halle et al., 1992. The data 

In Table 15.2.2.4, the results of these comparisons with the results of the Rhizobium test are presented. The Rhizobium test correlates well with Microtox , Daphnia, and particularly well with the 20 samples in the IC50 test. The comparison of the Rhizobium assays with other published results has been examined in detail (Botsford, 2000a). The Rhizobium test has been compared with values from several laboratories for the Microtox assay and correlation coefficients have varied from 0.750 to 0.893 indicating the two methods provide comparable results. Four comparisons with values for Daphnia have provided correlation coefficients from 0.776 to 0.953 indicating that the Rhizobium assay agrees well withZJa/ / -nia. 

= molecular weight of the compound n = number of times compound was tested var=variation in the results, the standard deviation /mean toxicity reported as mmoles toxin for the IC50 for the test. The rat test is an LD50. Rhizobium data are from this work. Microtox , HLD, and Daphnia data are from Calleja, (1993). The IC50 data (pooled data from animal cell tests) is from Halle et al., 1993. Rat hepatocyte data is from Shrivastava (1992). The IC50 samples include only 20 chemicals. The other methods involve about 34 chemicals. 

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Post-hoc consensus does not independently establish the value of the measurand, and although it provides internal consistency, comparison with other testing rounds and proficiency tests should be made with care. In some cases the outliers from the consensus mean in a round may be the only ones with the correct answer. When an empirical method is used to establish the assigned value, this method should be made known to the participants in advance. Where the assigned value is provided with an uncertainty (as it would be in cases 1-3 above), the uncertainty should be small compared to... 

Parks JS, Amrhein JA, Vaidya V, Moshang T Jr, Bongiovanni AM. Growth hormone response to propranolol-glucagon stimulation A comparison with other tests of growth hormone reserve. J Clin Endocrinol Metab 1973 37 85-92. 

The results of the testing performed using MARA to evaluate the sensitivity to confounding variables is summarized in Table 3.1.9. Data for comparison with other tests from previous studies are included. 

To obtain these (weight) concentrations, a defined volume V of the suspension is removed at the measuring location by means of a pipette (Figure 35). After evaporation of the sedimentation liquid the respective masses M(t) or Mq are determined by weighing. Ordinarily, the pipette analysis is considered as a very accurate method because potential sources of error can be well defined. Therefore, this technique is often used for calibration of and comparison with other test methods. 

Since experimentation is the only way to get information about the efficiency of a numerical procedure, test reports are a valuable support for the user of a program, provided the results can be reproduced and allow a comparison with other testings. The request for reproducibility requires that the report supplies information about the initial conditions (initial guess, fixed coordinates, parameters, etc.). Furthermore, a test report should involve the following information ... 

A practical method of predicting the molecular behavior within the flow system involves the RTD. A common experiment to test nonuniformities is the stimulus response experiment. A typical stimulus is a step-change in the concentration of some tracer material. The step-response is an instantaneous jump of a concentration to some new value, which is then maintained for an indefinite period. The tracer should be detectable and must not change or decompose as it passes through the mixer. Studies have shown that the flow characteristics of static mixers approach those of an ideal plug flow system. Figures 8-41 and 8-42, respectively, indicate the exit residence time distributions of the Kenics static mixer in comparison with other flow systems. 

Car-C.i = 1.52 A. and C -C = 1.37 A., these distances being 0.02 A. smaller than those given by our photographs. The rings given by mesitylene and hexamethylbenzene are unusually sharp and well defined, and we estimate, by comparison with other substances for which the electron-diffraction method has been tested,81 that the error in our values of sa is not greater than about 0.5%. 

Phenol no longer plays any significant role as an antibacterial agent. It is of historical interest, since it was introduced by Lister in 1867 as an antiseptic and has been used as a standard for comparison with other disinfectants, which are then given a phenol coefficient in tests such as the Rideal-Walker test. 

Worker safety studies are not likely to normally include a control substance (i.e., a material used in the study to serve as basis of comparison with the test substance). However, if a control substance is included as a treatment group, then it must (1) be fully characterized as to its identity, purity (or strength), and stability (and solubility, if appropriate) (2) be appropriately tested in mixtures with any carrier used and (3) meet all the other GLP recordkeeping, labeling, and storage requirements, as specified for the test substance. There is some regulatory relief here, however, in that water, by definition, is excluded from being considered a control substance, and vehicles (those substances added to enhance solubilization or dispersion of the test substance) are addressed separately in the FIFRA GLP Standards. 

Identify available information, including information from quality control charts, performance in proficiency testing rounds, literature and validation information on related methods and data concerning comparison with other methods. Use the available information and professional judgement to review each relevant validation issue and sign-off issues adequately addressed and documented. 

It should be emphasized that the results from RSST experiments use simplified calculation methods and give estimated values for stability and vent sizing. For large scale purposes, more dedicated and accurate measuring techniques may be needed for further hazard evaluation determinations. Due to the relatively recent development of this apparatus, comparison with other stability test methods is not yet comprehensive. 

Reference substance (EPA only) Any chemical substance or mixture, or analytical standard, or material other than a test substance, feed, or water, that is administered to or used in analyzing the test system in the course of a study for the purposes of establishing a basis for comparison with the test substance for known chemical or biological measurements. 

The selectivity of the method is usually investigated by studying its ability to measure the analyte of interest in test portions to which specific interferences have been deliberately introduced (those thought likely to be present in samples). Where it is unclear whether or not interferences are already present, the selectivity of the method can be investigated by studying its ability to measure the analyte by comparison with other independent methods or techniques. 

External QC can be external proficiency testing and comparison with other laboratories. 

The determination of antibody affinity (in M 1) is useful for comparison with other reported antibodies. However, the important test of affinity is how well the antibody performs. If more than one antibody has been prepared, a direct comparison of antigen binding curves will indicate the most avid preparation. 

By comparison with other NDC methods, such as liquid penetrant examination, magnetic particle, eddy current testing, and radiography, the ultrasonic method is the only technique that is applicable to a wide range of materials. 

For this reason, a standard crucible test has been devised in which the chief features, compared with other tests, are the use of a leveled coal surface, a crucible of special shape and unidirectional heating by a gas flame. As a result, regularly shaped coke buttons are obtained and the degree of swelling is assessed by comparison with profiles of standard buttons. 

More recently, such processes were tested to reduce the acidity of clarified passion fruit (Passiflora edulis v. flavicarpa) juices from pH 2.9 to 4.0 in comparison with other conventional processes, such as calcium citrate precipitation as resulting from CaC03 or Ca(OH)2 addition, or removal via weakly basic IER (Calle et al., 2002 Vera et al., 2003). Whatever the process tested, the physicochemical and sensory properties of the de-acidified juices were quite similar. In spite of the fact that their sodium concentration was higher when using any of the above-mentioned ED processes, the two-compartment stack using bipolar and anionic membranes (Figure 8C) was regarded as optimal, since no chemical consumption was needed and a valuable solution rich in citric acid (89% purity) was recovered (Vera et al., 2003). 

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