Nuclear magnetic resonance entry

Index Entries Escherichia coli polyhydroxyalkanoates fed-batch fermentation nuclear magnetic resonance differential scanning calorimetry. 

Nuclear magnetic resonance spectra. As well as numerous routine reports of NMR spectra (see individual entries in the Appendix Table of Simple Pyrazines), a brief correlation of II NMR spectra for 2-alkyl-3,5,6-triph-enylpyrazines (243) and the corresponding 2,3-dihydro derivatives (244) has appeared 137 in addition, a comparative 13C NMR study of 2-styrylpyrazine (245) with other styryldiazines and some styrylazines has been reported.1428... 

Nuclear Magnetic Resonance. The successful study of polymers in solution by high resolution NMR spectroscopy started with the pioneering work on the sequence structure of poly methyl methacrylate in 1960. Since then, an ever-increasing number of investigations have been carried out ranging from the elucidation of the statistics of homopolymer and copolymer structure to the study of conformation, relaxation and adsorption properties of polymers. The aspects of sequence length determination and tacticity have received considerable attention (Klesper 84, for example, reports more than 500 entries). Therefore, a detailed review will not be attempted. (For a detailed description of the NMR Theory and statistics of polymer structure, see Bovey 59, Randall 23, and Klesper 84). 

As is true with infrared and nuclear magnetic resonance spectroscopy, large libraries of mass spectra (>150,000 entries) are available in computer-compatible formats,- Most commercial mass spectrometer computer systems have the ability to rapidly search all or pari of such files for spectra that match or closely match the spectrum of an analyte. 

The following entry defines the commonly used stability constants (stepwise, overall, conditional, association, dissociation, and pK) and relates the values to a rigorous thermodynamic definition of equilibrium constants. In addition, the article briefly outlines experimental techniques (potentiometric titration, spectroscopic methods involving ultraviolet/visible, infrared, Raman, fluorescence. and nuclear magnetic resonance spectroscopy), together with the numerical methods and computer programs that can be used to derive stability constants from such experimental data. 

Figure 10 Components of the nuclear pore complex. Structures are available from the PDB and EMDB for some of the components of the nuclear core complex. The individual proteins and small subassemblies shown in ribbon representation are from six PDB entries that provide atomic-level information from X-ray (4GQ2, 3UKY, 4FHN, 3TKN, 4GQ1) or nuclear magnetic resonance spectroscopy (2EC1) studies. The three larger subassemblies drawn as surfaces have been analyzed by cryo-electron microscopy (EMD-5152, EMD-1097) or cryo-electron tomography (EMD-1394).

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