The Rule of

Lipinski et al. used the USAN (United States Adopted Name) and the INN (International Non-proprietary Name) lists to derive a database of compounds that entered phase II studies [33, 37] and therefore should not show major solubility or permeability problems. 

The rule of 5 states that poor absorption or permeation are more likely when two or more of these parameters are out of range. Exceptions are compounds that are substrates for biological transporters. A compound for which all parameters are within the ranges shows similar physico-chemical properties as typical drug molecules and is therefore drug-like (in terms of the physico-chemical properties considered). 

With this rule it is not possible to discriminate between compounds that are bioavailable and compounds that are not bioavailable. However, the filters allow us to select the more drug-like compounds from a virtual combinatorial library. 

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Porter, K. E., and Momoh, S. O., Finding the Optimum Sequence of Distillation Columns—An Equation to Replace the Rules of Thumb (Heuristics), Chem. Engg. J., 46 97, 1991. 

The representation of cooccurrence matrix as an image in 256 levels of gray necessitates a law of coefficients values transformation. In order that this law is common to all images, there will be no recodage on the maximum coefficient but on a theoretical maximal value. Thus the rule of conversion is the following ... 

This is not a new problem As stated by Sextus Julius Frontius 0097, water commissioner of Rome Nor is greater care required upon any works than upon such as are to withstand the action of water for this reason, all parts of the work need to be done exactly according to the rules of the art, which all the workmen know, but few observe. "... 

At its foundation level, statistical mechanics mvolves some profound and difficult questions which are not fiilly understood, even for systems in equilibrium. At the level of its applications, however, the rules of calculation tliat have been developed over more than a century have been very successfLil. 

The fimdamental kinetic master equations for collisional energy redistribution follow the rules of the kinetic equations for all elementary reactions. Indeed an energy transfer process by inelastic collision, equation (A3.13.5). can be considered as a somewhat special reaction . The kinetic differential equations for these processes have been discussed in the general context of chapter A3.4 on gas kmetics. We discuss here some special aspects related to collisional energy transfer in reactive systems. The general master equation for relaxation and reaction is of the type [H, 12 and 13, 15, 25, 40, 4T ] ... 

While the trivial and trade nomenclature in most cases has accidental character, the lUPAC Commission has worked out a series of rules [4] which allow the great majority of structures to be represented uniformly, though there still exists some ambiguity within this nomenclature. Thus, many structures can have more than one name. It is important that the rules of some dialects of the lUPAC systematic nomenclature are transformed into a program code. Thus, programs for generating the names from chemical structures, and vice versa (structures from names) have been created [5] (see Chapter II, Section 2 in the Handbook). 

This is a question of reaction prediction. In fact, this is a deterministic system. If we knew the rules of chemistry completely, and understood chemical reactivity fully, we should be able to answer this question and to predict the outcome of a reaction. Thus, we might use quantum mechanical calculations for exploring the structure and energetics of various transition states in order to find out which reaction pathway is followed. This requires calculations of quite a high degree of sophistication. In addition, modeling the influence of solvents on... 

The cutoff values of this Rtile of Five the thresholds are a multiple of five) differ slightly within the pharmaceutical industry. Sometimes the Rule of Five" is extended by a fifth condition ... 

When a specific value above is n ot hn own, the rule of Pauling (the van der Waals radius is approximately 0.76 A larger than the cova-len t radiiis) is u sed. 

Exchange any two columns of the detemiinant in the previous problem and evaluate the new determinant. Exchange any two rows of the determinant in the previous problem and evaluate the new determinant. Does the rule of Exercise 2-17 hold ... 

The rules of matrix-vector multiplication show that the matrix form is the same as the algebraic form, Eq. (5-25)... 

Aeeording to the rules of quantum meehanies as we have developed them, if F is the state funetion, and (jin are the eigenfunetions of a linear, Hermitian operator. A, with eigenvalues a , A( )n = an(l)n, then we ean expand F in terms of the eomplete set of... 

The nucleus of an atom is made up of protons and neutrons in a cluster. Virtually all the mass of the atom resides in the nucleus. The nucleus is held together by the tight pull of what is known to chemists and physicists as the "strong force." This force between the protons and neutrons overcomes the repulsive electrical force that would, according to the rules of electricity, push the protons apart otherwise. 

One of the most commonly used constructs is a model. A model is a simple way of describing and predicting scientific results, which is known to be an incorrect or incomplete description. Models might be simple mathematical descriptions or completely nonmathematical. Models are very useful because they allow us to predict and understand phenomena without the work of performing the complex mathematical manipulations dictated by a rigorous theory. Experienced researchers continue to use models that were taught to them in high school and freshmen chemistry courses. However, they also realize that there will always be exceptions to the rules of these models. 

If the medium is sufficiently basic to generate the arabident anion 31. mixtures of products resulting from N-nng and N-exocyclic reactivity are observed. Here again steric effects can preferentially orient the whole reaction toward one of the two nitrogens. A general study clearly delineating the rules of behavior for 31 accordine to the nature of R. the... 

It follows from Equation (6.58) that the 1q, 2q and 3q transitions of H2O are allowed since Vj, V2 and V3 are Ui, and 2 vibrations, respectively, as Equation (4.11) shows. We had derived this result previously simply by observing that all three vibrations involve a changing dipole moment, but the rules of Equation (6.57) enable us to derive selection rules for overtone and combination transitions as well. 

Process plant design has come a long way from the early 1930s when process designers used the rule-of-thumb that a process faciUty could not be scaled-up more than 10-fold (2). American Oil s Ultracracking unit (Texas City, Texas) for example, was designed from data from a small pilot plant with a scale-up factor of 80,000 (3). 

Diazo coupling follows the rules of orientation of substituents in aromatic systems in accordance with the mechanism of electrophilic aromatic substitution and the concept of resonance. 

The density p of the composite material is then related to the density of the fiber and matrix p by the rule of mixtures ... 

Eig. 10. The variation of the density of carbon-fiber reinforced epoxy resin with the fiber volume fraction, based on the rule of mixtures. 

Poisson s ratio, is the negative of the ratio of the strain transverse to the fiber direction, 8, and the strain ia the fiber direction, S, when the lamina is loaded ia the fiber direction and can also be expressed ia terms of the properties of the constituents through the rule of mixtures. 

The difference between the bounds defined by the simple models can be large, so that more advanced theories are needed to predict the transverse modulus of unidirectional composites from the constituent properties and fiber volume fractions (1). The Halpia-Tsai equations (50) provide one example of these advanced theories ia which the rule of mixtures expressions for the extensional modulus and Poisson s ratio are complemented by the equation... 

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