Almost no countries have chosen to first implement trials of these exemption measures; instead, most often the exemptions have been organized nation-wide, making it difficult (and sometimes impossible) to evaluate causal attributions for these innovations.
The compound concentrations were too low for accurate isotope analyses of benzene, toluene, 1- and 2-methylnaphthalene, while interferences in the chromatography made it impossible to evaluate the isotopic composition for 4-ethyltoluene, 1,3,5-trimethylbenzene and camphor.
Although the CD40/CD40L system is expressed both by endothelial cells and vascular smooth muscle cells [ 62] and thus may be important in the development of capillary leak syndrome [ 63, 64], the use of serum samples in our present study makes it impossible to evaluate whether CD40/CD40L is important for the pretransplant predisposition to capillary leak.
For example, it was impossible to evaluate several parameters such as the influence of the medical condition on care or the quality of BLS.
At least for us, it is impossible to evaluate such a large number of mutants in three different assay systems (in vitro phosphorylation, oocyte experiments, and mutant complementation).
For women, it was impossible to evaluate the influence of occupation on mortality since more than half of the women who had/had not changed their county of residence (52.5% and 51.3%, respectively) were registered as having no occupation.
There are other aspects of the proposed tests of equivalence that give cause for concern but it is impossible to evaluate these properly until the issue of interactions has been resolved.
Although the 5T murine model of myeloma is very effective and reliable for such preclinical studies, it is impossible to evaluate all drugs or combinations in vivo.
It was thought that it would add value to this project, but practical constraints made it impossible to evaluate the soundness of the empirical evidence supporting recommended standards for care.
Thus, well validated cough-specific health status questionnaires for COPD patients are absent, rendering it impossible to evaluate patients health status both individually and in clinical trials.
