Issues in study

To properly assess drug safety, we must be able to systematically tap the information captured in the massive amounts of medical data collected in both premarketing and postmarketing settings. In addition, as stated above, we must also be able to reproduce findings in different repositories of medical data in an auditable way. However, two major issues in studying drug safety confront us. 

Trial number and location and definition of specific crop fractions to be sampled had been a significant reason for study rejection prior to 1996. This particular guideline has helped resolve these issues in studies conducted since that time. 

Although continuum solvation models do appear to reproduce the structural and spectroscopic properties of many molecules in solution, parameterization remains an issue in studies involving solvents other than water. In addition, the extension of these approaches to study proteins embedded in anisotropic environments, such as cell membranes, is clearly a difficult undertaking96. As a result, several theoretical studies have been undertaken to develop semi-empirical methods that can calculate the electronic properties of very large systems, such as proteins28,97 98. The principal problem in describing systems comprised of many basis functions is the method for solving the semi-empirical SCF equations ... 

Salamone, J.D. (1996) The behavioral neurochemistry of motivation methodological and conceptual issues in studies of the dynamic activity of nucleus accumbens dopamine. / Neurosci Methods 64 137-149. 

Moreover, it is worth noting that most of our knowledge on the relationship between mood and sleep comes from patients with major depression, and for the last decade, from patients with moderate forms of depression. Ethical and safety issues in studying patients with a greater severity of symptoms, especially when patients are unmedicated, could explain the paucity of sleep EEG studies in manic disorder and in severe depression [10]. 

Chasnoff IJ. Methodological issues in studying cocaine use in pregnancy a problem of definitions. NIDA Res Monogr 1991 114 55-65. 

Spiegelhalter, D.J. Statistical issues in studies of individual response. 

Hsu CY, Chertow GM, Curhan GC. Methodological issues in studying the epidemiology of mild to moderate chronic renal insufficiency. Kidney Int 2002 61 1567-76. 

The basic issue in studying the growth of the oxide layer is to determine which ions carry the current through the oxide layer, i.e., Pb" or O. Using X-ray diffraction analysis, i.e., measuring the relative content of the PbO vs PbS04 phases in the anodic layer as a function of the quantity of electricity passed, it has been established that in general the thickness of the tet-PbO layer steadily increases. Hence, it can be assumed that the ionic conductivity is provided by the 0 ions [18]. 

Instituteof Medicine of the National Academies. 2012. Ethical and Scientific Issues in Studying the Saj cf Approved Drugs. Washington, DC National Academies Press. 

A key issue in studies of thermolysis kinetics in hitherto unexplored systems, including Hf-containing polymers, is the optimization of the experimental procedure. Preliminary thermodynamic analysis of the Hf-C-H-0 system offers the possibility of establishing the temperature stability limits of HfC and HfO. Earlier, thermodynamic studies of the Hf-C-H-O system were carried out in relation to hafnium acetylacetonate, which is used to prepare HfC [33]. The most convenient approach to producing hafnium-containing nanocomposites with the aim of... 

Dislocation-dissociation has been an important issue in studies of basal deformation in sapphire since the seminal studies of Kronberg [7], who suggested that basal dislocations would dissociate into half-partials via the reaction ... 

The complexation of DNA and polycations is a function of the intrinsic properties of the two components. For instance, from the use of synthetic polycations for complexing DNA also arises the problem of polydispersity of polymers (a polymer sample is usually composed of macromolecular species of differing molar masses) compared with DNA, which is monodisperse. Because the polydispersity of the polycation could be an issue in studies of IPECs, sugar-based polymers (usually polydisperse except if fractionated), conjugated polymers (polydispersity, Mw/Mn > 2), branched PEI derivatives, and hyperbranched polymers are out of the scope of this review, as already mentioned. Only polymers synthesized via controlled or living polymerization methods will be discussed [55-57]. 

One of the central issues in studying reaction dynamics isf how you describe the flux over the reaction barrier, whether from simple collision theory, or transition state theory, to modified generalized Langevin theory, Kramer s theory...or even to quantum mechanical tunnelling - This is a selective not exhaustive list of possibilities (7,8). When the timescale of the photo chemical event (be it photodissociation, isomerization, charge transfer)... 

Li B.F., Song B.F. and Xue H.Q., 2005, Analysis on Theoretical Issues in Study of Human Reliability in System Safety, China Safety Science Journal, 15, 21-23. 

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