Screening, definition precise

Screen validation phase tests the screening assay in a more production-like environment. For example, the lab bench results are replicated on the HTS robotic system. Critical quality control experiments are performed at this stage in the process. This involves screen rehearsal with a small number of compounds (i.e., a few thousand), thus validating the screening process. Process precision is measured by repeating the mini-screen on a different day. This procedure allows definition of all the quality control parameters. Typical values include the following ... 

Later, we shall give a more precise definition of the screening length c associated with the screening effect described above. However, we can already remark that, in the present case, c must be proportional to k and in the following chapters, we write... 

This approach gives only qualitative estimates. Thus, the definition of btll is not completely satisfactory and we could also introduce a ceff corresponding to three-body forces. It is certainly possible to do better by analysing the screening effects more precisely (see Sections 2.7 and 2.9). Finally, we note that experimentally the phenomenon described here has been observed53 as will be shown in Chapter 15. 

We have introduced here a parameter According to the definition, is one third of the second moment of the function 47rr (g(r) — (cm)), and is therefore a measure for the width of this function. On the other hand, as follows from a look at Fig. 3.8, this width essentially agrees with the screening length. Hence, we may identify with So far, there has been no precise definition of g Eq. (3.60) provides us with one. 

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