Ergodicity and efficiency of cross-polarization in NMR of static solids.
J Magn Reson. 2011 Apr;209(2):161-6
Authors: Nevzorov AA
Cross-polarization transfer is employed in virtually every solid-state NMR experiment to enhance magnetization of low-gamma spins. Theory and experiment is used to assess the magnitude of the final quasistationary magnetization amplitude. The many-body density matrix equation is solved for relatively large (up to N=14) spin systems without the spin-temperature assumption for the final spin states. Simulations show that about 13% of the thermodynamic limit is still retained within the proton bath. To test this theoretical prediction, a combination of a reverse cross-polarization experiment and multiple contacts is employed to show that the thermodynamic limit of magnetization cannot be transferred from high- to low-gamma nuclei in a single contact. Multiple contacts, however, fully transfer the maximum magnetization. A simple diffusion on a cone model shows that slow dynamics can affect the build up profile for the transferred magnetization.
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nmrlearner
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11-15-2011 10:36 AM
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Publication year: 2011
Source: Journal of Magnetic Resonance, Available online 9 November 2011</br>
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Publication year: 2011
Source: Journal of Magnetic Resonance, In Press, Accepted Manuscript, Available online 20 July 2011</br>
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Correlation of chemical shifts of low-? nuclei (such as 15N) is an important method for assignment of resonances in uniformly-labeled biological solids. Under static experimental conditions, an efficient mixing of low-? nuclear spin magnetization can be achieved by a thermal contact to the common reservoir of...
nmrlearner
Journal club
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07-21-2011 10:31 PM
Repetitive cross-polarization contacts via equilibration-re-equilibration of the proton bath: sensitivity enhancement for NMR of membrane proteins reconstituted in magnetically aligned bicelles
Repetitive cross-polarization contacts via equilibration-re-equilibration of the proton bath: sensitivity enhancement for NMR of membrane proteins reconstituted in magnetically aligned bicelles
Publication year: 2011
Source: Journal of Magnetic Resonance, In Press, Accepted Manuscript, Available online 2 July 2011</br>
Wenxing, Tang , Alexander A., Nevzorov</br>
Thermodynamic limit of magnetization corresponding to the intact proton bath often cannot be transferred in a single cross-polarization contact. This is mainly due to the finite ratio between the number densities of the high-...
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Authors: Hong M, Yamaguchi S
A method for enhancing the sensitivity of 15N spectra of nonspinning solids through 1H indirect detection is introduced. By sampling the 1H signals in the windows of a pulsed spin-lock sequence, high-sensitivity 1H spectra can be obtained in two-dimensional (2D) spectra whose indirect dimension yields the 15N chemical...
nmrlearner
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http://www.ncbi.nlm.nih.gov/corehtml/query/egifs/http:--highwire.stanford.edu-icons-externalservices-pubmed-custom-pnas_full_free.gif http://www.ncbi.nlm.nih.gov/corehtml/query/egifs/http:--www.pubmedcentral.nih.gov-corehtml-pmc-pmcgifs-pubmed-pmc.gif Related Articles Polarization transfer by cross-correlated relaxation in solution NMR with very large molecules.
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