Linear literature tests

A study is considered valid if the results obtained with positive and negative controls are consistent with the laboratory s historical data and with the literature. Statistical analysis is usually applied to compare treated and negative control groups. Both pairwise and linear trend tests can be used. Because of the low background and Poisson distribution, data transformation (e.g., log transformation) is sometimes needed before using tests applicable to normally distributed data. Otherwise, nonparametric analyses should be preferred. 

In the majority of the literature tests for linear programming, bound constraints are rarely provided and often only nonnegativity bounds are given (this is required by the Simplex and Interior Points methods). 

When structure-property relationships are mentioned in the current literature, it usually implies a quantitative mathematical relationship. Such relationships are most often derived by using curve-fitting software to find the linear combination of molecular properties that best predicts the property for a set of known compounds. This prediction equation can be used for either the interpolation or extrapolation of test set results. Interpolation is usually more accurate than extrapolation. 

In our next chapter we will discuss other methods of testing for linearity that have appeared in the literature. Afterward, we will then turn our attention to a new test that has been devised. In fact, it turns out that while DW has much to recommend it, it is not the final or best answer. The new method, however, is much more direct and specific even than DW. It is the correct way to test for linearity. We will discuss it all in due course, in this same place. 

So we now proceed to present various linearity tests that can be found in the statistical literature ... 

HPLC methods can usually be transferred without many modifications, since most commercially available HPLC instruments behave similarly. This is certainly true when the columns applied have a similar selectivity. One adaptation, sometimes needed, concerns the gradient profiles, because of different instrumental or pump dead-volumes. However, larger differences exist between CE instruments, e.g., in hydrodynamic injection procedures, in minimum capillary lengths, in capillary distances to the detector, in cooling mechanisms, and in the injected sample volumes. This makes CE method transfers more difficult. Since robustness tests are performed to avoid transfer problems, these tests seem even more important for CE method validation, than for HPLC method validation. However, in the literature, a robustness test only rarely is included in the validation process of a CE method, and usually only linearity, precision, accuracy, specificity, range, and/or limits of detection and quantification are evaluated. Robustness tests are described in references 20 and 59-92. Given the instrumental transfer problems for CE methods, a robustness test guaranteeing to some extent a successful transfer should include besides the instrument on which the method was developed at least one alternative instrument. 

Fig. 10 relates the composite extraction index (see above) obtained in the low-shear aqueous test system for these Tween surfactants, and adhesion tensions measured against various solids. Adhesion tensions against platinum and bitumen saturated pyrophyllite are irregularly related to tar sand extraction, while the adhesion tension against a fresh pyrophyllite surface is linearly (inversely) related to tar sand extraction. This is the first linear correlation between a measurable property of a surfactant solution and tar sand extraction which we have been able to obtain, and there appears to be no such finding in the literature. Fig. 11 gives the relations between extraction of bitumen with the paddle mill, solvent-aqueous-surfactant extraction and adhesion tensions measured against platinum, bitumen saturated pyrophyllite and hydrated (48 hours in water) pyrophyllite. 

Fig. 13. Relationship between the normalized apparent dissolution rate of HT materials, r(glaxs)l1(lnn and their free energy of hydration, ACh>lir. calculated for the pH values measured after one day and 10 days of corrosion. For comparison, the literature-extracted results (Plodinec and Wicks 1994) obtained for 115 glasses of different origins corroded under the conditions of the MCC-I test are reproduced. For simplicity, data obtained after three days of corrosion are not shown their linear fit lies between the ones of the one-day and the 10-day corrosion experiments.

Thermal stability as measured by these ramped TGA experiments of the sort previously described are not the definitive test of a polymer s utility at elevated temperature. Rather, for a polymer to be useful at elevated temperatures, it must exhibit some significant retention of useful mechanical properties over a predetermined lifetime at the maximum temperature that will be encountered in its final end use application. While many of the bisbenzocyclobutene polymers have been reported in the literature, only a few have been studied in detail with regards to their thermal and mechanical performance at both room and elevated temperatures. Tables 7-10 show some of the preliminary mechanical data as well as some other physical properties of molded samples of polymers derived from amide monomer 32, ester monomer 40, diketone monomer 14 and polysiloxane monomer 13. The use of the term polyamide, ester etc. with these materials is not meant to imply that they are to be regarded as merely modified linear thermoplastics. Rather, these polymers are for the most part highly crosslinked thermosets. 

The most important application for bismaleimide resin is multilayer boards. The development in this area requires resins with low dielectric constants. It is well documented in the literature that fluorine containing linear polyimides show lower dielectric constants vis a vis their non-fluorinated counterparts. Recently, Hitachi Research Laboratory, Japan, reported the thermal and dielectric behaviour of fluorine-containing bismaleimides (29). The chemical structures of the fluorinated BMIs investigated are provided in Fig. 6. The non-fluorinated four aromatic rings containing BMI, 4,4 -bis(p-maleimidophenoxyphenyl) propane, was tested in comparison. 

Therefore, specific information is required on the characteristics of detectors to allow one to be selected for a particular application. In many cases, however, major performance characteristics of detectors such as noise, sensitivity, response, and linearity, are not presented in a standard format by suppliers. To complicate matters further, there are no published reference values for many of the properties utilized by different detectors for most analytes. Therefore, to determine whether a particular detector is adequate for a particular application, a similar analysis in the pertinent literature has to be found. Ultimately, the analyst will often have to test the detector under consideration on the analyte of interest itself. 

From sand test values (B) detd at PicArsn for ca 20 expls(using 0.4 g samples in both 200-g and 1700-g bombs) and from data available in the literature for their deton velocities (D) at approx their max densities, Rinkenbach obtained a nearly linear relationship on plotting B vs D. This permitted the following equations to be derived ... 

Other Statistical Tests for Linearity Several other tests are for linearity have been described in the literature the test for significance of the quadratic... 

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