Physics-Based Methods

Because of the R variability and the high root mean square error (RMSE) values, we believe that MM-PBSA and MM-GBSA methods are generally not accurate enough to predict ligand affinity. 

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To account for the effect of a sufficiently broad, statistical distribution of heterogeneities on the overall transport, we can consider a probabilistic approach that will generate a probability density function in space (5) and time (t), /(i, t), describing key features of the transport. The effects of multiscale heterogeneities on contaminant transport patterns are significant, and consideration only of the mean transport behavior, such as the spatial moments of the concentration distribution, is not sufficient. The continuous time random walk (CTRW) approach is a physically based method that has been advanced recently as an effective means to quantify contaminant transport. The interested reader is referred to a detailed review of this approach (Berkowitz et al. 2006). 

The purpose of this chapter is not to promote the replacement of traditional physically based methods of assessing groundwater-lake systems with isotopic methods, but rather to demonstrate the utility of isotopic techniques. Physically based methods can provide more detailed information on the spatial and temporal variability of a groundwater-lake system than isotopic approaches can provide. Regardless of the method chosen, however, an adequate number of piezometers is necessary to ensure that groundwater samples are collected from upgradient areas. 

Huang, N. and Jacobson, M.P. (2007) Physics-based methods for studying protein-ligand interactions. Current Opinion in Drug Discovery e[ Development, 10, 325-331. 

From a historical point of view, the analysis of food is performed predominandy using typical chemical or physicochemical methods. These are, for example, wet chemical methods for proximity analysis or chromatographic methods for the analysis of pesticides and veterinary dmg residues. In addition, food chemists use such physics-based methods as viscosity measurement and atomic absorption spectroscopy for the analysis of heavy metals. 

Physics-based methods are implemented when direct analysis of the system or its resources is feasible. With regard to the human system, such methods are commonly applied in biomechanical analysis where unknown parameters, such as joint torque, are derived from known characteristics, such as segment lengths and reaction forces, based on estabhshed physical laws and relationships. 

Lion, A. (1997) A physically based method to represent the thermomechanical behavior of elastomers. Acta Mechanica, 123, 1-25. 

The hypothesis that geometrical derivatives of the electric dipole moment can be used as effective charges of the atoms in a neutral diatomic molecule was initially proposed by Van Vleck. After decades of development the APT became customarily applied. In their spunky paper Lazzeretti et aV described a version of the APT approach that they claimed is probably superior to other physically based methods, and certainly more rehable on theoretical grounds than some loosely defined orbital-based approach. In their critical review of population methods they presented AIM favourably. 

As reaction intermediates are often present at very low levels or with a veiy short lifetime (or both at the same time), physics-based methods are more suitable for their analysis, especially methods focused on the use of spectroscopy and resonance. Among the most frequently used methods are ... 

With heterogeneorrs reactions leading to the formation of a solid, the reaction intermediates, including adsorbed gases, are terrrporary defects. This knowledge was gained by the use of physics-based methods electric conductivity. Hall effect, spectroscopies, etc. 

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