Flexibility index model

Novartis uses the In Silico Profiling web tool. Available properties include the octanol water partition coefficient log P, molar refractivity, flexibility index, hydrogen bonding characteristics and molecular polar surface area. Various drug properties, such as intestinal absorption, BBB permeability or Plasma Protein Binding (PPB) are calculated based on in-house models. 

In case of flexibility index and depth of water penetration both ratios obtained high values the correlation ratio values were higher than 0.92 and determination ratio values were higher than 0.85. High values of R and R indicate that the model is close to the empiric data from laboratory tests and that the variability of tested feature strongly (in at least 85%) depends on the variability of the input variables. 

Janzen [44] argued that Eq. 5.65 is not a suitable model for linear melts, because the parameter, a, affects both the breadth of the transition from Newtonian to power-law dependence of viscosity on frequency and the power-law index. Janzen found that it was necessary to use the HN function (Eq. 5.61) to describe the viscosity, thus adding a fourth parameter, in order to have sufficient flexibility to model the behavior of molten polymers and relate the parameters to molecular structure. When applied to the complex viscosity, the HN function is... 

The main parameters used to describe a polymer chain are the polymerization index N, which counts the number of repeat units or monomers along the chain, and the size of one monomer or the distance between two neighboring monomers. The monomer size ranges from a few Angstroms for synthetic polymers to a few nanometers for biopolymers. The simplest theoretical description of flexible chain conformations is achieved with the so-called freely-jointed chain (FJC) model, where a polymer consisting of N + I monomers is represented by N bonds defined by bond vectors r/ with j= Each bond vector has a fixed length r,j = a corresponding to the... 

In the Wonderland model, a pathological scenario was identified of very low values of the human development index, dependent on extreme values of two of the 41 variables. In the experiment with 500 runs, only three runs exhibited this behavior fewer runs in the design or a less flexible approximation strategy may well have missed this feature. 

A related qualifier is the extent to which some particular model for some site- or scenario-specific use is flexible for multiple uses by the regulator or risk manager. For example, biokinetic models such as EPA s lEUBK model for children (U.S. EPA, 1994a,b,c) or the O Flaherty PB-PK model for children and adults (O Flaherty, 1995, 1998) theoretically permit assessment of the results of altered land uses, altered population demographics, or impact of lead remedial actions when projecting into future years for body lead burdens indexed by PbB. Such applications should not require recalibration with empirical data for every use. 

It is important to emphasize that the SOR is not the inevitable consequence of fundamental physical principles rather, it is a very plausible hypothesis, which has extensive experimental support for polymer solutions and melts. In other words, there is no reason to assume that the SOR is valid under all possible flow conditions or for all possible polymer liquids. Some situations under which the SOR is expected to fail are mentioned in the next section. Many constitutive relations for solutions and melts predict that the SOR will hold, but even this apparent generality is somewhat misleading. The derivation of an SOR starts at a measurable molecular property, the optical polarizability of an isolated molecule a, and leads to a macroscopic refractive index tensor n, in a nontrivial way several substantial assumptions are necessary. Most rheological models (for flexible chains) that proceed to an SOR assume the derivation of Kuhn and Gritn (1942) for the polarizability anisotropy of a Gaussian subchain and thus in a sense make the same assumptions for the optical half of the SOR (Larson, 1988). Therefore differences between constitutive relations and their predictions for an SOR usually stem from differences in the calculation of t. 

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