NMR spectra of many systems governed by axially symmetric second rank tensor interactions exhibit P2(cos θ) dependence on the angle 9 between the symmetry axis and the externally applied magnetic field. For the so-called "powder samples" consisting of many randomly oriented domains the resulting spectrum is the superposition of contributions from each such domain. This study deals with a numerical technique enabling one to obtain the lineshapes of such individual contributions responsible for the given powder spectrum. The electric dipolar interaction between two spin 1/2 nuclei produces a characteristic powder lineshape called "Pake doublet", after G.E.Pake, hence the name "de-pake-ing". An iterative algorithm capable of dealing with spectra produced by a variety of systems is developed and checked by applying it to a wide range of simulated NMR spectra. A set of characteristic "signatures" associated with different experimental situations is established and the limits of the applicability of the technique are determined. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Note:

LCModel, which is performed on Linux, has been widely used for quantitative analysis of MRS. Its interface, LCMgui, converts MRS data of various formats to RAW file for LCModel analysis automatically. In this work, we had a web-based MRS analysis tool for GE MRS, GE MRS with Phase-Array and GE 2D-MRSI and improve the capability of web-based MRS analysis tool for GE 3D-MRSI, Siemens MRS/MRSI, and Philips MRS/MRSI. Meanwhile, T2 correction has been involved in the absolute quantification with LCModel. With the same echo-time, the different T2 value of each metabolite results in different degree of signal decay. In order to correct and make absolute concentrations more accurate, we exploit a factor to correct effect of different T2. Two groups of MRS data (TE = 35 and 272 ms) have been studied for comparison.

Report (M.S.)--Virginia Polytechnic Institute and State University. M.S. 1991. / Vita. Abstract. Includes bibliographical references. Also available via the Internet.

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Dissertation submitted in partial compliance with the requirements for the Master's Degree in Technology: Homoeopathy, Technikon Natal, 1997. / The purpose of this investigation was to analyse and compare the Nuclear Magnetic Resonance (NMR) spectra of samples of quinquagenimillesimal (LM) potencies of homoeopathic Sulphur and a lactose-based control produced according to Hahnemann, in order to evaluate homoeopathic medicines thus prepared. It was hypothesised that differences existed in the spectra of respective Sulphur samples, control samples, and between parallel samples of Sulphur and control. It was further hypothesised that these differences correlated proportionately with the degree of potency of samples. The design of the investigation was that of a scientific experiment. Potencies of Sulphur and a lactose-based control were prepared (according to the directions of Hahnemann*) to the LM10 level. LM2, LM6 and LM10 liquid potencies (95% ethanol) of each group were then prepared in =20.8160 ml volumes and despatched for sampling and measurement. NMR spectroscopy was conducted on fifteen (15) samples of each potency. These were prepared in coaxial sample tubes using deuterium oxide (020) as an extemal lock and dioxane as a reference. Samples were drawn and measured in overlapping sequence by the Department of Chemistry, University of Cape Town. The spectrometer em. ployed was a. Varian VXR200 operating at a frequency of 200.057 MHz. Acquisition time for each sample was 3.727 seconds, using a pulse width of 6\xB0. Measurement of each sample was repeated eight times, at a constant temperature of 298.1 K (250. OC) / M

Thesis (Ph. D.)--University of Queensland, 2002. / Includes bibliographical references.

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