No description available.

No description available.

No description available.

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

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.

No description available.

Thesis (Ph.D.)--University of Delaware, 2006. / Principal faculty advisor: Tatyana Polenova, Dept. of Chemistry & Biochemistry. Includes bibliographical references.

This dissertation reports a study of three kinds of liquid crystals using modern solid state NMR techniques: chiral rod-like liquid crystals, bent-core mesogens and disc-like liquid crystals. The properties and structures of liquid crystals are first introduced in Chapter 1. To understand the principles of different NMR phenomena, quantum mechanical theory is adopted to study different nuclear spin interactions and NMR techniques in Chapter 2. In the next part of this dissertation (Chapter 3-6), deuterium NMR methods are used to investigate the dynamics and structures of some liquid crystal phases. This is first done using the spin relaxation study. The parameters obtained from the model simulation can describe the molecular motion and internal dynamics in the fast motion region. Secondly, we investigate the dynamic process of discotic mesophases and unwound smectic C* phase using the line shape simulation study. 2D deuterium NMR exchange experiments are then performed to study the jump process in TGBA* phase and SmC* phase. The above investigation has demonstrated some powerful NMR methods for the dynamic study of liquid crystals. The third part of the dissertation (Chapter 7-9) is concerned with C-13 NMR techniques. After we introduce the quantum theory of different pulse sequences, theoretical models are presented to fit observations such as chemical shifts and dipolar splittings. Moreover high resolution liquid C-13 NMR experiments are introduced to study some bent-core molecules. They are useful to assist the carbon peak assignments of these molecules. The structure and ordering information of liquid crystals can be determined in their mesophases. Finally, a brief summary of the dissertation is given in the last chapter. / October 2007

Thesis (M.S. in chemical engineering)--Washington State University, December 2009. / Title from PDF title page (viewed on Jan. 21, 2010). "Department of Chemical Engineering." Includes bibliographical references (p. 28-31).

Thesis (Ph. D.)--University of Missouri--Rolla, 1993. / Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed January 25, 2010) Includes bibliographical references (p. 150-155).