Closed test procedure

Marcus, R., Peritz, E., and Gabriel, K. R. (1976). On closed testing procedures with special reference to ordered analysis of variance. Biometrika, 63, 655-660. 

To develop the test, we use the closed testing procedure of Marcus et al. (1976). This procedure requires the construction of a size-a test of the hypothesis... 

Let ci denote the upper-a quantile of the distribution of 7 when all It effects are zero. Then, the test that rejects 77o,/ if 7) > c/ is a size-a test of the null hypothesis because the test statistic 7) is a nonincreasing function of Pi for each K I (Voss and Wang, 2005). For each i, the closed testing procedure rejects 770jl Pi = 0 if and only if H0j is rejected for each 7 containing i. Use of this procedure controls the simultaneous error rate to be at most a see Marcus et al. (1976). It requires the... 

Closed test procedure. A structured approach to multiple comparisons and controlling the type I error rate, whereby all higher-level hypotheses in which lower-level hypotheses are implicated must be rejected before rejection of the lower-level hypotheses themselves. 

Since the composition of the unknown appears in each of the correction factors, it is necessary to make an initial estimate of the composition (taken as the measured lvalue normalized by the sum of all lvalues), predict new lvalues from the composition and the ZAF correction factors, and iterate, testing the measured lvalues and the calculated lvalues for convergence. A closely related procedure to the ZAF method is the so-called ())(pz) method, which uses an analytic description of the X-ray depth distribution function determined from experimental measurements to provide a basis for calculating matrix correction factors. 

These ratings can be interpreted as follows. In the case of the Time Stress PIF, all the operations have a high level of time stress, apart from close test valve, where stress is low. The operators are very experienced in carrying out all the tasks. Distractions are moderately high for close test valve, but otherwise low. Procedures are poor for secure locking nuts and secure blocking device, but above average for the other two tasks. 

The design for the surface water-collector system is determined by an allowable flow rate divided by a required flow rate. Allowable rates for geocomposites are determined experimentally by exactly the same method as for geonets. The specific cross section used in the test procedure should replicate the intended design as closely as possible. For the required flow rate, Darcy s law or HELP36 37 can be used. Then the design-by-function concept is used to determine the DR, or FS. 

For the dissolution test to be used as an effective drug product characterization and quality control tool, the method must be developed with the various end uses in mind. In some cases, the method used in the early phase of product and formulation development could be different from the final test procedure utilized for control of the product quality. Methods used for formulation screening or BA and/or bioequivalency evaluations may simply be impractical for a quality control environment. It is essential that with the accumulation of experience, the early method be critically re-evaluated and potentially simplified, giving preference to compendial apparatus and media. Hence, the final dissolution method submitted for product registration may not necessarily closely imitate the in vivo environment but should still test the key performance indicators of the formulation. 

Sinkers can significantly influence the dissolution profile of a drug. Therefore, the use of sinkers should be part of the dissolution method validation. If equivalent sinkers are identified during the sinker evaluation and validation, the equivalent sinkers should be listed in the written dissolution test procedure. When a dissolution method utilizes a dissolution sinker and is transferred to another laboratory, the receiving laboratory should duplicate the validated sinker design(s) as closely as possible. 

There were no positive reactions to 5% DBP among 53 subjects given a 48-hour closed-patch test. Cosmetic formulations containing up to 9% DBP ranged from nonirritating to slightly irritating in various patch test procedures. Sensitization and photosensitization did not occur. ... 

Once a critical instrument loop is identified, a procedure for testing the entire loop must be written. The test procedure will influence the design of the new system, since, if possible, the test should be an actual performance test. For example, if a high temperature should close a valve, the ideal test would consist of raising the temperature to see if the value closes. Efforts should be made to avoid test procedures which require temporary wiring disconnects, valve closures, and so on, which might not be returned properly to operating condition. 

Closely examine the considerations in Sec. 9.3.3. Use these to scale up the HETP from the above steps to your column. Pay attention to effects of diameter, height, and wetting. Judgment is required. It may pay to look at the original reference from which the data were derived in order to check whether distribution, data scatter, or test procedure have influenced the data. 

The rate of peel loading is more important than in lap shear loading, and it should be known and controlled as closely as possible. The rate at which the load is applied is usually specified in the ASTM test procedure. Adhesive thickness also has a significant effect on peel strength values, as does the angle of peeling. 

In spite of the fact that HFB derivatives have a number of properties suitable for GC analysis, their use for steroids suffers from various problems, as can be judged from the different results obtained by different workers. Wotiz and co-workers [356,357] reported a detection limit of 0.1 ng of steroids and stated that if estrogens are determined in plasma, 2 ng per 10 ml of plasma can be analysed. Derivatization was performed by the following procedure. A 0.1-ml volume of -hexane, 1 jul of tetrahydrofuran and 2 jul of HFB anhydride were added to the estrogen fraction and the mixture was heated in a closed test-tube at 60°C for 30 min. The solvent was evaporated under a moderate stream of nitrogen at 40—50°C and the residue was dissolved in 50 jul of -hexane. GC was performed on 3% QF-1 or 2% XE-60 at 240°C. 

Acyl derivatives of triazines were used by Bailey et al. [495] for their determination in potatoes, peas and tomatoes. Their preparation requires catalysis by trimethylamine or pyridine. A 15-jul volume of HFB anhydride was added to a dry residue of triazine (1—25 ftg) in a 15-ml test-tube fitted with a screw-cap, 1.0 ml of 0.5 M trimethylamine in benzene (or 1 ml of benzene plus 6 droplets of pyridine) was then added and the closed test-tube was stirred gently for 30 sec and then allowed to stand at room temperature for 30 min. Subsequently 4.0 ml of benzene were added and the contents were stirred for 1 min, then 10 ml of water were added and the contents were shaken vigorously for 1 min. The phases were separated and a suitable portion of the benzene phase was injected. Several stationary phases (OV-1, OV-101, OV-210 and a mixture of OV-101 and QF-1) were applied at temperatures of 180—200°C or with temperature programming. Exclusively mono-derivatives are said to be prepared by this procedure, with bis-deriva-tives in small amounts and for only some substrates. The sensitivity of the analysis using an ECD is from 300- to several thousand-fold higher that with free substances. 

Closely related to preventive action is the process audit. Such an audit is performed as part of a laboratory assessment for each test on the proposed scope of accreditation. Performance of a test procedure is observed relative not only to the requirements of the ISO 17025 standard (or ISO Guide 25) but also with respect to performing the ASTM or ISO test method properly. As a minimum, the laboratory must have properly calibrated equipment, the current test method, and trained testing personnel. In addition, a representative number of test demonstrations will reveal whether good laboratory practices are observed in sample preparation, using the correct test parameters and calculating the results. When operators and technicians accept responsibility through such demonstrations, they tend to commit to the quality process. Real improvement occurs with involvement at all levels. 

Regarding the overpressure test, an overpressure of 1.5 times the reference pressure is required by the d-standards, with a minimum of 3.5 bar (referring to atmospheric pressure). This test may be a static test using a liquid (oil, water) or compressed air (in this case, to avoid parts of an enclosure which fails becoming dangerous projectiles, the overpressure test shall be made with a barrier - e.g. within a closed testing vessel) or a dynamic test based upon the same procedure as described for the determination of the reference... 

Today, five main aspects must be taken into account machines, chemicals, environment, farmer, and agricultural products. These five aspects must be considered as a unique system or a dynamic system with close interaction (Fig. 3). Future standards should take these into consideration in the development of better quality in agriculture and environment. Standards should clearly define test procedures to ensure uniformity within all institutions carrying out tests. 

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