Detailed Molecular Analysis

Although distillation and elemental analysis of the fractions provide a good evaluation of the qualities of a crude oil, they are nevertheless insufficient. Indeed, the numerous uses of petroleum demand a detailed molecular analysis. This is true for all distillation fractions, certain crude oils being valued essentially for their light fractions used in motor fuels, others because they make quality lubricating oils and still others because they make excellent base stocks for paving asphalt. 

In summary, the results from this and other studies (30, 31, 32) unambiguously demonstrate that simple solvent extraction of coal liquids does not yield chemically well-defined fractions. Consequently, detailed molecular analysis is a prerequisite for an in-depth analysis/prediction of the production and/or upgrading of coal liquids and for the correct evaluation of process effectiveness. In addition, implementation of routine process control/monitoring schemes employing fractions obtained from separation of products/reactants necessarily requires calibration by detailed molecular analysis. Finally, the separation method(s) should produce fractions possessing chemical significance. 

Polycrystalline and well-oriented specimens of pure amylose have been trapped both in the A- and B-forms of starch, and their diffraction patterns84-85 are suitable for detailed structure analysis. Further, amylose can be regenerated in the presence of solvents or complexed with such molecules as alcohols, fatty acids, and iodine the molecular structures and crystalline arrangements in these materials are classified under V-amylose. When amylose complexes with alkali or such salts as KBr, the resulting structures86 are surprisingly far from those of V-amyloses. 

Recent advances in glycobiology have significantly increased interest in nematode glycoconjugates (Dell et al., 1999a,b). As detailed structural analysis deciphers the intricate labyrinth of their molecular architecture, functional issues are beginning to be rationally addressed. It is anticipated that a better understanding of the glycobiology of nematode parasitism... 

The value of 3 and its dispersion can be theoretically calculated from equation 6, provided a complete set of electron states of the system is known. Such quantum mechanical calculations have been developed based on molecular Hartree-Fock theory including configuration interactions( 1 3). A detailed theoretical analysis of 3 and contributing 1T -electron states has been presented for several important molecular structures. 

We first discuss the materials research which includes monomer synthesis, growth of monomer crystalline structures and polymerization in the solid state, yielding the requisite polymer structures. Next, the nonlinear optical experimental research is discussed which includes a novel experimental technique to measure x (w). Linear and nonlinear optical data obtained for the polydiacetylene films is subsequently presented. Detailed theoretical analysis relating the data to x (< >) and subsequently to its molecular basis will be discussed in a later publication. 

For the case of catalytic model sites based on metallocenes 23, a detailed molecular mechanics analysis has also been conducted for the case of primary or secondary propene insertions on secondary polypropylene chains... 

Combining 2D-NOESY and 2D-ROESY NMR experiments with molecular modelling protocols, Kuhn and Kunz32 have been able to study the saccharide-induced peptide conformational behaviour of the recognition region of Ll-Cadherin. The detailed conformational analysis of this key biomolecule not only proves that the saccharide side chain exerts a marked influence on the conformation of the peptide chain, but also that the size and type of the saccharide indeed strongly affects the conformation of the main chain. 

Ethylene was one of the first systems subjected to detailed vibrational analysis using HOCM modified to account for lattice anharmonicity. Agreement with experiment is excellent (Fig. 5.5). The differences in the VPIE s of the equivalent isotopomers cis- trans-, and gem-dideuteroethylene (Fig. 5.6) are of considerable interest since they neatly demonstrate the close connection between molecular structure and isotope chemistry. The IE s are mainly a consequence of hindered rotation in the liquid (moments of inertia for cis-, trans-, and gem-C2D2H2 are slightly... 

In a subsequent communication, Elliott and coworkers found that uniaxially oriented membranes swollen with ethanol/water mixtures could relax back to an almost isotropic state. In contrast, morphological relaxation was not observed for membranes swollen in water alone. While this relaxation behavior was attributed to the plasticization effect of ethanol on the fluorocarbon matrix of Nafion, no evidence of interaction between ethanol and the fluorocarbon backbone is presented. In light of the previous thermal relaxation studies of Moore and co-workers, an alternative explanation for this solvent induced relaxation may be that ethanol is more effective than water in weakening the electrostatic interactions and mobilizing the side chain elements. Clearly, a more detailed analysis of this phenomenon involving a dynamic mechanical and/ or spectroscopic analysis is needed to gain a detailed molecular level understanding of this relaxation process. 

Theoretical analyses of the reaction path of photocyclization point to the same conclusion. Thus the qualitative state correlation procedure clearly indicates that photocyclization takes place by a conrotatory process in the Orbital Symmetry Conservation sense requiring a C2 molecular symmetry in 7 and in its symmetric congeners. The same conclusion were reached in the subsequent numerical analysis of the photocyclization of 7 and of 44 The detailed molecular structures of these two molecules and of 61 have been calculated by semi-empirical energy minimization procedures (cf also Ref. ). 

In a series of papers, we have proposed the torsional mechanism of energy transduction and ATP synthesis, the only unified and detailed molecular mechanism of ATP synthesis to date [16-20,56] which addresses the issues of ion translocation in Fq [16, 20, 56], ionmotive torque generation in Fq [16, 20, 56], torque transmission from Fq to Fj [17,18], energy storage in the enzyme [17], conformational changes in Fj [18], and the catalytic cycle of ATP synthesis [18, 19]. We have also studied the thermodynamic and kinetic aspects of ATP synthesis [19,20,41,42,56]. A kinetic scheme has been developed and mathematically analyzed to obtain a kinetic model relating the rate of ATP synthesis to pHjn and pH m in the Fq portion and the adenine nucleotide concentrations in the Fj portion of ATP synthase. Analysis of these kinetic models reveals a wealth of mechanistic details such as the absence of cooperativity in the Fj portion of ATP synthase, order of substrate binding and product release events, and kinetic inequivalence of ApH and Aip. 

The chemical and physical properties of ribosomes are well characterized (for reviews see The exact understanding of their function, however, still lacks a detailed molecular model. Appropriate methods such as image reconstruction from electron micrographs of two-dimensional sheets, or X-ray structure analysis, all depend on the crystallizability of the material. 

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