Targeting assessment definition

Wel et al. 2005). Further studies will have to assess if more accurate target volume definition translates into improved patient prognosis. 

While isolation of a specific inhibitor will be necessary to assess the definitive role of the cytosolic nuclease in the low transfection efficiency in vivo, circumstantial evidence suggests that the metabolic instability of plasmid DNA represents one of the cellular barriers to gene transfer. Microinjection of DNA complexes with PEI has augmented the transfection efficiency (Pollard et al., 1998). Although the stability of the PEI-complexed DNA has not been determined in vivo, it has been demonstrated that the nuclease resistance of plasmid DNA is dramatically increased upon complex formation in vitro (Cappaccioli et al., 1993 Chiou et al., 1994 Thierry et al., 1997). Therefore, it is conceivable that faster diffusional mobility and decreased nuclease susceptibility jointly lead to the enhanced nuclear targeting efficiency of the PEI-condensed plasmid DNA. 

For non-SI traceable quantities the predominant objective must be an agreement on the definition of these quantities on an international basis before reference measurement procedures can be developed and used for assigning target values in external quality assessment. 

The quantitative structure-activity relationship (QSAR) model is by definition a model. Any model, such as animal model (also called in vivo) or in vitro model, is a system that applies to a specific situation, and thus, it is useful to study, evaluate, or assess a more complex system, which cannot be used experimentally for investigation. Thus, any model is a simplification of the target object of the study, and the model is useful for this or not depending on its purpose. It is also possible to imagine a series of models, each addressing one or more features of the more complex system. 

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