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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

Magnetic Resonance Imaging (MRI) has been used to provide high-resolution tomographic information, valuable in the study of static vocal tract. However, speech does not present a static behaviour but relies on the continuous and dynamic interaction of the vocal tract articulators and neighbouring tissues. Thus, this could make real-time MRI (rt-MRI) an essential tool to assess speech, with numerous advantages over the current clinical techniques. However, using rt-MRI to image the upper vocal tract remains challenging; the motion of the articulators, including the velum is fast while MRI data acquisition is slow thus inherently limiting temporal resolution. Additionally, an intrinsic loss in SNR, spatial resolution and/or visual image quality is present. The main focus of this thesis is to increase clinical reliability of rt-MRI in speech by investigating novel methodologies for the imaging of velopharyngeal motion. Firstly, commercial rt-MRI protocols at 1.5 T and 3 T were compared, regarding image quality and temporal resolution compromise. Optimal imaging protocols were suggested for both eld strengths. This provided a starting point for future clinical translation and the use of commercial and currently available protocols to image velopharyngeal motion. Furthermore, imaging of velopharyngeal motion was further improved with non-standard acquisition methods, such as non-Cartesian sampling and more advanced reconstruction schemes. An improved imaging protocol for the assessment of velopharyngeal motion was suggested. This was based on a highly accelerated radial trajectory with a novel parallel imaging reconstruction method (radial tt-GRAPPA). The suggested protocol not only allowed for improved image quality and image sharpness,but it was also viable for future clinical translation regarding o offline computation times compared to other reconstruction methodologies also investigated in this thesis. In summary, this thesis added some novel insights into the eld of speech rt-MRI, presenting improved and time effcient imaging protocols, adequate for the assessment of velopharyngeal motion.

Introduction: The Elastography Software Library (ESL) was developed to achieve clinically feasible, super-resolution (SR) Magnetic Resonance Elastography (MRE). ESL was created by accomplishing four objectives: 1. perform a critical analysis of MRE inversion, using discrete-time Fourier transform (DTFT) methods, to enable selection of the wave inversion approach most suitable to high- and SR MRE (Chapter 2) 2. develop a new method for real-time 4D phase unwrapping, to enable large acquisitions to be processed in clinical work ow (Chapter 3) 3. develop a new inversion pipeline that recovers fine features in elastograms (Chapter 4) 4. extend this pipeline with a novel interpolation technique to achieve super-resolution (Chapter 5) The results of these experiments were combined to make the ESL. Over the course of the work, two objectives also resulted in software applications in their own right (PhaseTools for phase unwrapping, and Elastography Software Pipeline (ESP) for fine feature elasticity map recovery). Methods: Critical Analysis: Two-filter cascades were designed to model the signal processing pipelines found in the present MRE literature. These models were subjected to DTFT-based analysis to determine the relative advantage of various mathematical approaches to the MRE inverse problem. Phase Unwrapping: A test data set was developed to measure algorithm performance in 4D on data sets with varying levels of wrap, gradient and noise. The algorithms that performed most accurately and efficiently on test data were then applied to in vivo brain, liver, and muscle data, of both moderate and severe wrap, and inspected for wrap failure. Fine Feature Recovery: A new MRE image processing pipeline was developed that incorporates wavelet-domain denoising, image-driven noise estimation, and feature detection. ESP was first validated using simulated data, including viscoelastic Finite Element Method (FEM) simulations, at multiple noise levels. ESP images were then compared with Multifrequency Dual Elasto-Visco Inversion (MDEV) pipeline images in three ten-subject cohorts of brain, thigh, and liver acquisitions. Finally the proportion of spectral energy at fine frequencies was quantified using the Reduced Energy Ratio (RER) for both ESP and MDEV. Super-Resolution: An extension of the ESP pipeline was developed that incorporated a new image fusion technique to combine non-redundant information. The algorithm was validated on an analytic simulation program developed for the study. An in vivo cross-validation was performed between 1X, 2X and 4X magnification levels measuring both spectral gains and shear modulus values. Results: Critical Analysis: The more complex, heterogeneous FEM models were found to only outperform Algebraic Helmholtz Inversion (AHI) in very low noise, with Gaussian smoothing of σ > 0:8px or Butterworth low-pass cutoffs of < 0:8π negating any advantages from assumption of local heterogeneity. Phase Unwrapping: Three algorithms were determined to perform with sufficient robustness in real-time on 4D data sets with challenging phase wrap. These algorithms were then applied to in vivo brain, skeletal muscle, liver and phantom data and shown to successfully resolve heavy phase wrap within a \real-time" criterion of under 3 minutes. Fine Feature Recovery: For FEM inversions, mean values of background and soft target simulated results remained within 8% of prescribed up to σ = 10% for both jG*j and ϕ, though inspection of the ϕ image showed scatter- and boundary-related artefacts around the soft target. Hard target results showed jG*j means within 7% of prescribed up to σ = 5% but unreliable ϕ means, and inspection showed showed scatter- and boundary-related artefacts. For the in vivo cohorts, ESP results showed mean correlation of R = 0:83 with MDEV and liver stiffness estimates within 7% of Local Frequency Estimation (LFE) results. Finally, ESP showed statistically significant increase in fine feature spectral energy as measured with RER for both jG*j (p < 1X10-9) and ϕ (p < 1X10-3). Super-Resolution: At 4X SR, both brain and liver cohorts showed a highly significant (p ≤ 10-6) increase in both number of recovered frequencies and normalised spectral energy in those recovered frequencies. Both the 2X and 4X SR techniques showed a decrease in stiffness estimate from the original resolution (mean decrease of 11.6% and 14.0%) respectively; however cohort correlations between SR and original values were upwards of R = 0:988. Discussion: Established as a technique highly sensitive to important tissue changes, MR Elastography is now also a finely-featured super resolution technique in two parameters, enabling new clinical and research applications. Future work includes statistical mapping of both localised and diffuse soft tissue changes, rapid computation on heterogeneous processing architectures, and two-parameter super-resolution MRI-based lesion mapping.

Neurophysins (NPs) make up a relatively small, stable, and highly soluble class of proteins. They have physiological roles of storage and stabilizing' of peptide hormones oxytocin and vasopression within the posterior pituitary neurosecretory granules. At the concentration of NP found within the granules, NP would exist as a dimer in the absence or presence of bound peptide. The NP monomer-monomer interface involves B-sheet/ B-sheet contact, which can be modulated by the presence of cosolvent. This remarkable feature of NP makes it a model for Alzheimer's disease. One of the characteristics of Alzheimer's disease is the presence of plaques of B-amyloid protein that are deposited on the brain. The plaques are rich in B-structure. Being water-insoluble makes them impossible to be directly studied by solution-state NMR. The purpose of this study was to modify the solvent system to lower the NP dimerization constant and characterize the nature of solvent on dissociation of dimer. A set of cosolvents was selected to try to reduce NP dimerization at relatively high concentration of NP. The organic cosolvents included deuterated methanol, dimethyl sulfoxide, ethyl acetate, propionitrile, and acetonitrile. Also, the protein unfolding reagents, deuterated urea and guanidine monohydrochloride, were tried. The interaction between bromophenol blue and NP was also studied because this dye binds predominately to the dimer form of NP. Highresolution NMR techniques were used to sense the NP-I dimer I monomer equilibrium. Among the organic cosolvents used, only acetonitrile and propionitrile were found shift the dimer ~ monomer equilibrium significantly toward monomer. The cosolvent probably changed the character of the solvent system, penetrated the monomer-monomer interface and interacted with the interface residues, caused the break up of dimer. The unfolding reagents were found to partly unfold the NP simultaneously with dissociation of the dimer. Bromophenol blue binds to NP-I at low pH, but the solubility of NP-dye complex is too low to be studied extensively by solution-state NMR methods.