Levi molecular theories

In microscopic approaches the solvent molecules are described as true discrete entities but in some simplified form, generally based on fotee-field methods (Allinger, 1977). These theories may be of the semicontinuum type if the distant bulk solvent is accounted for, or of the fully discrete type if the solvent description includes a large number of molecules. As an example, the spectrum of formaldehyde in water has been examined using a combination of classical molecular dynamics and ab initio quantum chemical methods and sampling the calculated spectrum at different classical conformations (Blair et al., 1989 Levy et al., 1990). These calculations predict most of the solvent shift as well as the line broadening. 

These results are in agreement with the suggestion of Meyer et al. (1940), that silk fibroin is composed of two parts, an amorphous part of complex amino acid composition and a crystalline part built up simply of Gly.Ala units linked together. This theory was based on the observation that the X-ray data could be fitted by a unit cell containing four parallel Gly.Ala residues. It was considered that some of the alanine residues in the crystalline part could be replaced by serine since its molecular dimensions are similar. Clearly the idea of a long chain containing glycine and alanine alternately is untenable in view of the results of Levy and Slobodiansky since in such a case the yields of Ala.Gly and Gly.Ala should be equal. However such a sequence could be broken up to a certain extent by serine residues. 

Rezac J, Levy B, Demachy I, de la Lande A (2012) Robust and efficient constrained DFT molecular dynamics approach for biochemical modeling. J Chem Theory Comput 8(2) 418 27. doi 10.1021/ct200570u... 

Lipid removal may be a critical factor in plaque formation and the location of lecithin-cholesterol trans-acylase in the arterial wall could play an important role since cholesterol is rapidly exchanged" with the blood while cholesterol ester is not. Kuo in an editorial cites the evidence for the theory that a dlsturbemce in carbohydrate metabolism can be responsible for atherosclerosis and should be included as one of the primary risk factors in coronary heart disease. In this regard, Clements and coworkers have shown the presence in aorta of aldose reductase, an enzyme which they feel provides a mechanism for the alteration of arterial metabolism by hyperglycemia. Another approach to molecular interactions was described by Levy and Day who concluded from their results that the low density lipoproteins are uniquely polycationic at the surface and that these ions react with the internal arterial macromolecular polyanions. 

W. J. Pietro, B. A. Levi, W. J. Hehre, and R. F. Stewart, Inorg. Chem., 19, 2225 (1980). Molecular Orbital Theory of the Properties of Inorganic and Organometallic Compounds. 1. STO-NG Basis Sets for Third Row Main-Group Elements. 

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