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Developing a numerical inverse-theory-based extraction of orientation-dependent relaxation rates from partially- relaxed spectra

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dc.contributor.author Ghamari, Mohammad Sedigh en_US
dc.date.accessioned 2010-03-09T20:22:58Z
dc.date.available 2010-03-09T20:22:58Z
dc.date.issued 2010-03-09T20:22:58Z
dc.identifier.uri http://hdl.handle.net/10464/2942
dc.description.abstract Second-rank tensor interactions, such as quadrupolar interactions between the spin- 1 deuterium nuclei and the electric field gradients created by chemical bonds, are affected by rapid random molecular motions that modulate the orientation of the molecule with respect to the external magnetic field. In biological and model membrane systems, where a distribution of dynamically averaged anisotropies (quadrupolar splittings, chemical shift anisotropies, etc.) is present and where, in addition, various parts of the sample may undergo a partial magnetic alignment, the numerical analysis of the resulting Nuclear Magnetic Resonance (NMR) spectra is a mathematically ill-posed problem. However, numerical methods (de-Pakeing, Tikhonov regularization) exist that allow for a simultaneous determination of both the anisotropy and orientational distributions. An additional complication arises when relaxation is taken into account. This work presents a method of obtaining the orientation dependence of the relaxation rates that can be used for the analysis of the molecular motions on a broad range of time scales. An arbitrary set of exponential decay rates is described by a three-term truncated Legendre polynomial expansion in the orientation dependence, as appropriate for a second-rank tensor interaction, and a linear approximation to the individual decay rates is made. Thus a severe numerical instability caused by the presence of noise in the experimental data is avoided. At the same time, enough flexibility in the inversion algorithm is retained to achieve a meaningful mapping from raw experimental data to a set of intermediate, model-free en_US
dc.language.iso eng en_US
dc.publisher Brock University en_US
dc.subject Nuclear magnetic resonance spectroscopy. en_US
dc.subject Lipids--Analysis. en_US
dc.title Developing a numerical inverse-theory-based extraction of orientation-dependent relaxation rates from partially- relaxed spectra en_US
dc.type Electronic Thesis or Dissertation en_US
dc.degree.name M.Sc. Physics en_US
dc.degree.level Masters en_US
dc.contributor.department Department of Physics en_US
dc.degree.discipline Faculty of Mathematics and Science en_US


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