Dynamic characterization

Within physical chemistry, the long-lasting interest in IR spectroscopy lies in structural and dynamical characterization. Fligh resolution vibration-rotation spectroscopy in the gas phase reveals bond lengths, bond angles, molecular symmetry and force constants. Time-resolved IR spectroscopy characterizes reaction kinetics, vibrational lifetimes and relaxation processes. 

Bai, Y W., Chung, J., Dyson, H. J., and Wright, P. E. (2001). Structural and dynamic characterization of an unfolded state of poplar apo-plastocyanin formed under nondenaturing conditions. Protein Sci. 10, 1056-1066. 

Radu JEF, Novak L, Hartmann JF et al (2008) Structural and dynamical characterization of poly-y-glutamic acid-based cross-linked nanoparticles. Colloid Polym Sci 286 365-376... 

Eliezer D., Yao J., Dyson H. J. and Wright P. E. Structural and dynamic characterization of partially folded states of apomyoglobin and implications for protein folding. Nat. Struct. Biol. (1998) 5(2) 148-155. 

The convenient NMR observables depend on the characteristics of the system studied, but generally the protons of the liquid are readily detected. The apparent NMR linewidths are often determined by the magnetic susceptibility inhomogeneities in the sample and do not directly reflect the dynamics of the liquid. This report will focus largely on theoretical approaches to understand the spin-lattice relaxation rate constants for both classes of microporous materials. The magnetic held dependence of the spin-lattice relaxation rate constant generally provides a useful dynamical characterization of the liquid and often a structural characterization of the confining media. 

To compare the time scales of the dynamics characterization produced by each model, the spectral density or correlation function can be written as a distribution of exponential correlation times. For a correlation function, (t), the general expression is CO... 

Yield stress values can depend strongly on filler concentration, the size and shape of the particles and the nature of the polymer medium. However, in filled polymer melts yield stress is generally considered to be independent of temperature and polymer molecular mass [1]. The method of determining yield stress from flow curves, for example from dynamic characterization undertaken at low frequency, or extrapolation of shear viscosity measurements to zero shear rate, may lead to differences in the magnitude of yield stress determined [35]. 

However, these discussions based on the MO calculations are only relevant for the reaction at 0 K, and the interpretation of the reaction mechanism ought to rely on reaction dynamics at finite temperature. Ab initio direct MD calculations are a means to obtain the desired dynamical characterization. 

In the pharamaceutical industry, NMR spectroscopy has demonstrated itself to be a powerful, highly versatile tool that has impact throughout the drug discovery process. NMR is frequently used as an assay to screen compound collections, to facilitate the assessment of hits, and to provide detailed structural and dynamical characterization of protein-ligand complexes. Because NMR can provide information in discrete units, the spectroscopist can fine tune data collection strategies. 

Besides the time-averaged and the dynamic characterizations, the correlations between different scales add more complexities to the meso-scale structure. For example, the intensive exchange between meso-scale clusters and dispersed particles will reduce the cross-correlation coefficient and then make it hard to discern a cluster from broth. Such complexity requires more efforts in exploring the dominant mechanisms underlying the correlations, which will be discussed and exemplified by multi-scale CFD in later sections. 

Computerized real-time measurements and analysis of the coefficient of friction, contact high-frequency acoustic emission, and pad wear allow the effective evaluation of consumables, understanding of tribological interactions at the polishing interface, process development, dynamic characterization of the polishing process, including rate and nonuniformity of material removal, and so on. The application of tribometrology not only is restricted to research and development departments but also proves very useful in the device production facilities. 

Babini E, et al. A structural and dynamic characterization of the EF-hand protein CLSP. Structure 2006 14 1029-1038. 

H NMR spectroscopy combined with different techniques (see Section 4.05.3.6) has been used to perform the dynamic characterization of fananserin 35, an anxiolytic drug which can be crystallized as four different polymorphs. The dynamics were monitored by measuring the spin-lattice relaxation and line-shape evolution temperature dependence <2006MI798>. 

Dielectric relaxation, temperature-modulated differential scanning calorimetry (TMDSC), and H NMR spectroscopy (see Section 4.05.3.2.1) have been used to perform the dynamic characterization of fananserine 35. The use of these three different techniques gives a coherent set of information and allowed the authors to describe the dynamic properties over a wide range of frequencies and temperatures <2006MI798>. 

Sarrade S, Rios GM, and Carles M. Dynamic characterization and transport mechanisms of two inorganic membranes for nanoflltration. 

Banci, L., Schroder, S. and Kollman, P. A. (1992) Molecular Dynamics Characterization of the Active Cavity of Carboxypeptidase A and Some of Its Inhibitor Adducts, Proteins Struct. Func. Gen 13, 288 -305. 

A. Magistrate, W. DeGrado, U. RothUsberger, and M. Klein (2003) Structural and Dynamical Characterization of Dizinc DPI, a Biomimetic Compound of Diiron Proteins via ab initio and Hybrid (QM/MM) Molecular Dynamics. J. Phys. Chem. B 107, p. 4182... 

Photochemistry has expanded enormously since those first days. A serious percentage of the papers in any single volume of the Journal of the American Chemical Society, for instance, can rightly fall in its purview. The emergence of the laser and the evolution of theoretical methods strongly influenced research. With new computational methodology almost no intermediate lives too short a time to be detected and its dynamics characterized. The fundamental objective of our field, elucidation of the history of a molecule that absorbs radiation, is now within reach in even the most complicated cases. We hope that the series continues to reflect the frontiers of photochemistry as it evolves into the future. 

C. Guizard, C. Mouchet, R. Vacassy, X. Bouisson and V. Thoraval, Zirconia nanofiltration membranes II. Performance of the membranes, dynamic characterization with model solutes, in preparation. 

From such a background, the structure and dynamics of Si-based polymer materials by solid-state NMR have been widely used in order to make reliable polymer designs and to develop new advanced polymer materials. Details of the most recent work on structural and dynamic characterization of Si-based polymer materials by solid-state NMR will be reviewed, in addition mention is made of a review on inorganic polymer materials by Takayama. ... 

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