This thesis includes three studies examining the role of the type I (NPT1) and type II (NPT2) renal sodium (Na+)-phosphate (Pi) cotransporter genes in inherited hypophosphatemias. In the first study, the chromosomal locations of the NPT1 and NPT2 genes in human and rabbit are determined by physical mapping techniques. The NPT1 and NPT2 genes map respectively to human chromosomes 6p22 and 5q35 and to rabbit chromosomes 12p11 and 3p11. The localization of the two cotransporter genes to autosomes excludes them as candidate genes for X-linked hypophosphatemia. In addition, these assignments agree with the previously reported homology between rabbit chromosome 12 and human chromosome 6 and provide the basis for the establishment of a conserved syntenic group between rabbit chromosome 3 and human chromosome 5. / The goal of the second study was to clone, sequence and characterize the structure of the human NPT2 gene in order to design intronic primers to amplify NPT2 exons from patient DNA. Parallel experiments were performed on the mouse Npt2 gene, so that a vector could be designed to knockout the mouse Npt2 gene. In both species, the type II renal Na+-Pi cotransporter gene is approximately 16kb in length and is comprised of 13 exons and 12 introns. This work provides a basis for the study of the regulation of NPT2 transcription and facilitates the screening of DNA samples from patients with autosomally inherited disorders of renal Pi reabsorption for mutations in the NPT2 gene. / In the third study, polymorphic markers flanking the NPT1 and NPT2 genes were typed in members of a Bedouin kindred segregating the autosomal disorder Hereditary hypophosphatemic rickets with hypercaloiuria (HHRH). Genotype data were examined for excess homozygosity and allele sharing among affected pedigree members. Data did not reveal excess allele sharing on either chromosome 6 or 5, where the NPT1 and NPT2 genes are located, but suggested chromosome 3p as a site for further investigation. Identification of a HHRH locus is the first step toward identifying a gene involved in the pathophysiology of this disorder.

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Conduction electron interactions in sodium and potassium studied by magnetic resonance techniques Christopher D. Latham Department of Physics, Stocker Road, University of Exeter, EX4 4QL, UK. Abstract Pure sodium consists of a mixture of body centred cubic (BCC) and hexagonal close packed (HCP) crystals at low temperatures and these two phases exhibit subtly di?erent many body e?ects despite their almost identical conduction electron densities. This thesis represents a ?rst attempt to unravel the di?erences in the values of the many body parameters which characterize the description of the two phases in terms of the Fermi liquid theory. Fresh theoretical estimates of several many body parameters are presented and shortcomings in earlier theoretical work are highlighted. It has been found that the cause of these e?ects can be attributed to the di?erent and anisotropic phonon spectra in the two crystal phases. This has little e?ect on the lowest order many body parameters; the cyclotron e?ective masss, m * c, the paramagnetic susceptibility, ?p and the Landau-Silin Fermi liquid theory spin coe?cient, B0; but the second spin coe?cient B1 is very di?erent in the two crystal phases; it also seems likely that it is highly anisotropic. This di?erence leads to the observation of splittings in the microwave transmission spin wave spectra and di?erent spin wave coalescence angles for the two phases. Experimental results of measurements on sodium are presented. The conduction electron spin resonance (CESR), observed by the 35 GHz microwave transmission spectometer at Exeter, is split into two distinct lines which can be identi?ed with the two crystal phases present. A continuum region between the lines indicates that there is some averaging of electron spins among crystal grains or there may be some sodium present in an intermediate, faulted crystal phase in the samples. These observations con?rm the earlier work of Myler (1982), who used re?ection methods, and demonstrate with exceptional clarity, the presence of the two crystal phases. Analysis of the microwave transmission spectra, in various ?eld orientations, of spin waves, Gantmakher-Kaner oscillations, and cyclotron wave signals shows no observable di?er¬ences between the two phases of the quantities m * c, ?p and B0. The estimated values, con?rmed by spin wave measurements, of B1 are -0.01 ± 0.01 in BCC sodium and -0.05 ± 0.01 in HCP sodium at 5 K. The strong possibility of anisotropy in B1 may result in ambiguity in the values obtained from spin wave measurements depending on the details of the methods used to solve for the various quantities. For the ?rst time the microwave frequency size e?ect (MFSE) has been properly identi?ed and measured for potassium metal. This is the microwave frequency version of the radio frequency size e?ect but with the additional complication that the time of ?ight of the conduction electrons across the sample is comparable with the period of the microwaves. The electron orbits are identi?ed as being the symmetrical “type II” orbits, in the terminology of size e?ect studies. Unusually high quality spectra obtained during the early test work on the 35 GHz spectrometer enabled this study to be made. August 1987

A series of experiments was conducted to investigate the potential influence of pre- and post adding of catalysts to a demineralized coal char. The catalysts were chosen according to yield better catalytic activity and be inexpensive. CO2 gasification was conducted on the samples in a temperature range of 500 °C to 900 °C. The coal chosen was a high-inertinite, high-ash, Highveld bituminous coal. The catalysts chosen were sodium carbonate, potassium carbonate, and a mixture of the two catalysts. Different methods were used to investigate the factors influencing the reactivity of the demineralized coal char, and the extent of the influence from the catalysts. Proximate analysis, ultimate analysis and ash yields were conducted on the starting material to determine the change the demineralization had on the coal. Ash fusion temperatures of the samples were also obtained. The results indicated that demineralization lowered the ash content, as well as the ash fusion temperatures, but the ultimate analysis showed consistency in both sets of samples. Mass losses obtained during the thermal treatment experiments under CO2 atmosphere showed an increase in mass loss in the order of samples without addition of catalysts to the smallest amount of addition. Potassium carbonate showed the largest increase in mass loss during CO2 thermal treatment, together with the mixture of the two catalysts. Samples with pre-added catalysts also had a larger mass loss than samples with post-added catalysts. According to the XRD and QEMSCAN results, some potassium species are retained in the ash, which is confirmed by XRF results. The XRF results also showed that the amount of alkali species retained is quite large. / Thesis (M.Sc. (Chemistry))--North-West University, Potchefstroom Campus, 2011

Two series of oxa-amide ionophores based on 2-phenylglycerol and cis-cis- 1,3,5-cyclohexanetriol with ligand coordination numbers of 4, 5 and 6 have been synthesised and studied. Complexation of the ligands with group Ia and IIa metal ions was studied using IR, (^13)C NMR and electrospray mass spectroscopy. Potentiometric membrane electrodes have been prepared and their performance evaluated using a fixed interference method. Ionophores based on the hexadentate cyclohexyl triamide show excellent Na(^+)/K(^+) selectivity (-logK (^pot)(_Na,K) = 3.1), and the pentadentate analogue shows good Li(^+)Na(^+) selectivity (-logK (^pot)(_Na,K) = 2.2), Ligands based on 2-phenylglycerolexhibited good Ca(^2+) selectivity which was highest for the hexadentate triamide. The attempted synthesis of two 14-crown-4 fluorophores is reported as well as the synthesis and evaluation of an 18-crown-6 based fluorophore. The 18-crown-6 fluorophore shows a bathochromic fluorescent shift in the presence of potassium ions. Additionally a fluorophore was prepared based on a tri (napthylmethyl oxaamide) derivative of cis-cis-1,3,5-cyclohexane and its fluorescence characteristics assessed. A reduction in fluorescence intensity was observed with increasing concentrations of calcium and sodium ions.

Calcium polyphosphate (CPP) is a suitable substrate in a novel tissue-engineering strategy. The strategy aims to culture articular cartilage in vitro onto porous CPP and then implant the biphasic construct into the joint to replace damaged cartilage. CPP substrates should degrade faster to enhance repair. This project examined the structural and degradation effects of doping CPP with sodium phosphate, sodium hydroxide, and sodium carbonate. Doping concentration was narrowed to 0.01 Na2O/CaO for comparable phase composition to pure CPP. All doped groups sintered and crystallized at lower temperatures than pure CPP. Hydroxide-doped CPP did not form adequate sinter necks. At similar open porosity, Phosphate-doped CPP had similar diametral strength than pure CPP, while Carbonate-doped CPP had greater diametral strength. Degradation in vitro showed that Phosphate-doped CPP had greater strength loss, while Carbonate-doped CPP had similar strength loss, compared to pure CPP. Both doped groups degraded more slowly than pure CPP.

Calcium polyphosphate (CPP) is a suitable substrate in a novel tissue-engineering strategy. The strategy aims to culture articular cartilage in vitro onto porous CPP and then implant the biphasic construct into the joint to replace damaged cartilage. CPP substrates should degrade faster to enhance repair. This project examined the structural and degradation effects of doping CPP with sodium phosphate, sodium hydroxide, and sodium carbonate. Doping concentration was narrowed to 0.01 Na2O/CaO for comparable phase composition to pure CPP. All doped groups sintered and crystallized at lower temperatures than pure CPP. Hydroxide-doped CPP did not form adequate sinter necks. At similar open porosity, Phosphate-doped CPP had similar diametral strength than pure CPP, while Carbonate-doped CPP had greater diametral strength. Degradation in vitro showed that Phosphate-doped CPP had greater strength loss, while Carbonate-doped CPP had similar strength loss, compared to pure CPP. Both doped groups degraded more slowly than pure CPP.

Osteoarthritis is characterized by pain and inflammation in joints, typically weight-bearing joints such as the knee. An early warning sign of osteoarthritis is the loss of proteoglycan molecules in the cartilage matrix. A surrogate method for measuring proteoglycan loss is detection of sodium ions, which ionically bond to negatively charged glycosaminoglycan side chains. Sodium MRI has the potential to non-invasively measure proteoglycan content, and hence act as a diagnostic tool for osteoarthritis. However, as sodium MRI suffers from low sodium concentrations in vivo and reduced MR sensitivity compared to standard proton MRI, techniques are required which optimize signal. This thesis examines the hardware, software, and acquisition techniques required in order to achieve high resolution, excellent quality sodium MR images of the human knee in vivo, which has potential applications in early diagnosis as well as pharmacological treatment evaluations of osteoarthritis.

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