Relaxation times of spin states of all ranks and orders of quadrupolar nuclei estimated from NMR z-spectra: Markov chain Monte Carlo analysis applied to 7Li+ and 23Na+ in stretched hydrogels
| Autor: | David Szekely, Max Puckeridge, Philip W. Kuchel, Christoph Naumann, Bogdan E. Chapman |
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| Rok vydání: | 2011 |
| Předmět: |
Nuclear and High Energy Physics
Magnetic Resonance Spectroscopy Spin states Rank (linear algebra) Radio Waves Biophysics Context (language use) Lithium Carrageenan Biochemistry Molecular physics Spectral line symbols.namesake Nuclear magnetic resonance Isotopes Deuterium Oxide Physics Estimation theory Sodium Water Hydrogels Markov chain Monte Carlo Condensed Matter Physics Markov Chains Maxima and minima Data Interpretation Statistical symbols Relaxation (physics) Sodium Isotopes Monte Carlo Method Algorithms |
| Zdroj: | Journal of Magnetic Resonance. 212:40-46 |
| ISSN: | 1090-7807 |
| DOI: | 10.1016/j.jmr.2011.06.006 |
| Popis: | The NMR z -spectra of 7 Li + and 23 Na + in stretched hydrogels contain five minima, or critical values, with a sharp “dagger” on the central dip. The mathematical representation of such z -spectra from spin-3/2 nuclei contains nine distinct (the total is 15 but there is redundancy of the ± order-numbers) relaxation rate constants that are unique for each of the spin states, up to rank 3, order 3. We present an approach to multiple-parameter-value estimation that exploits the high level of separability of the effects of each of the relaxation rate constants on the features of the z -spectrum. The Markov chain Monte Carlo (MCMC) method is computationally demanding but it yielded statistically robust estimates (low coefficients of variation) of the parameter values. We describe the implementation of the MCMC analysis (in the present context) and posit that it can obviate the need for using multiple-quantum filtered RF-pulse sequences to estimate all relaxation rate constants/times under experimentally favorable, but readily achievable, circumstances. |
| Databáze: | OpenAIRE |
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