Thesis (Ph. D.)--University of Pennsylvania, 1932.

Thesis (M. Med. Sc.)--University of Hong Kong, 1992.

Thesis (M.Med.Sc.)--University of Hong Kong, 1992. / Also available in print.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1949. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 120-121).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1966. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

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Indiana University-Purdue University Indianapolis (IUPUI) / In present study, single quantum (SQ) and triple quantum filtered (TQF) 23Na magnetic resonance imaging (MRI) was used to monitor the severity and progression of CCl4 induced acute and chronic liver damage in rat model. SQ 23Na MRI was proposed to measure the 23Na signal intensity (SI) of total tissue sodium ions, and TQF 23Na MRI was proposed to measure the SI of intracellular sodium ions. In addition, shift reagent aided 23Na and 31P magnetic resonance spectroscopy (MRS) was used to measure in vivo intracellular sodium concentration ([Na+i]), total tissue sodium concentration ([Na+t]) and relative extracellular space (rECS) of liver in the same model. In acute high dose CCl4 intoxication, 24 hours after single dose of CCl4 in 5ml per kg body weight of mixture of CCl4 and oil in 1:1 ratio, SQ 23Na SI increased by 83% and TQF 23Na SI increased by 174% compared to the baseline level. According to SR-aided 23Na and 31P MRS, [Na+i] increased by 188% and [Na+t] increased by 43%. In addition, there was significant decrease in cellular energetic level, represented by ATP/Pi ratio. Histology examination showed pronounced inflammatory response in centrilobular regions, with neutrophiles infiltration, fatty accumulation and swollen hepatocytes. In chronic 8-week experiment, chronic damage was induced by biweekly administration of CCl4 in a dosage of 0.5 ml per kg body weight. From week 1 to week 6, SQ 23Na SI remained relatively constant, and then increased by 15% from week 6 to week 8. TQF 23Na SI progressively increased from week 1 to week 8, totally by 56%. Both SQ and TQF 23Na SI showed significant difference between treated group and control at every week. SR-aided 23Na and 31P MRS experiment showed that, at the end of 8-week CCl4 intoxication, both [Na+t] and rECS were higher than control, by 49% and 47% respectively; however, there was no significant difference for [Na+i] between two groups. Histology examination showed excessive deposition of extracellular matrix. In conclusion, SQ and TQF 23Na MRI appears valuable in the functional assessment of liver in noninvasive approach, and could be a promising diagnostic modality for liver diseases in clinical area.

Thesis (M. Sc. (Physics)) -- University of Limpopo, 2021 / Titanium is the most abundant element in the earth’s crust and can be produced as both a metal and in powder form. It finds applications in various industries such as in medical and aerospace, where the fabrication of components with excellent corrosion and high temperature performance are significant. This metal also plays a significant role in the titanium production process due to its desirable physical and chemical properties. However, this process occurs in the presence of alkali metal and alkali earth metal salt mediums. In this study, a combination of computational modelling techniques was employed to investigate the LiCl, TiCl, TiCl2 and TiCl4 systems and their interaction with titanium cluster (Ti7) at various temperatures. The density functional theory-based codes were used to study the structures and stability, while the classical force-fields codes were employed to study the temperature effect on these systems. Firstly, the LiCl model was validated using Buckingham interatomic potentials from the Catlow-library, employing the GULP code. The selected potential parameters were able to reproduce the LiCl structure to within 1% in agreement with experimental data. Furthermore, the Ti-Cl and Ti-Li interatomic potential parameters from accurate first principle calculations describe the interaction of LiCl and Ti7 cluster. The new interatomic potential parameters were deduced as Ti-Cl: 𝐷𝑒= 0.400, 𝑎0= 1.279, 𝑟0=2.680 and Ti-Li: 𝐷𝑒 =0.730, 𝑎0=1.717, 𝑟0=2.000. vi Secondly, DL_POLY code was used to characterise both the bulk LiCl and Ti7/LiCl structures employing rigid ion and shell models. It was found that the diffusion coefficient of LiCl was 6.26 nm2 /s, which corresponds to the melting temperature range of 700 K – 800 K for the rigid ion model. This agrees well with the experimental melting temperature range of 877 K – 887 K. The shell model predicts a lower melting temperature range of 600 K – 700 K at a diffusion coefficient of 3.74 nm2 /s, compared to rigid ion model. This behaviour was confirmed by the broadness of peaks on the RDF graphs at this temperature. The RDF graphs for the Ti7/LiCl structure in both rigid ion model and shell model depict a change in the morphology of the system for all interactions as the temperature is increased. It was found that the shell model is preferential for the LiCl structure. Thirdly, the elastic and mechanical properties of the TiCl, TiCl2 and TiCl4 structures were evaluated. It was found that the TiCl2 and TiCl4 structures are elastically unstable. However, the mechanical properties indicated that TiCl2 and TiCl4 are mechanically stable. The TiCln structures, namely TiCl and TiCl2, were evaluated for rigid ion model, to check the transferability of potentials. It was found that the diffusion coefficient of TiCl was 32.02 nm2 /s, which corresponds to a melting temperature of 700 K. The diffusion coefficient for TiCl2 was 115.00 nm2 /s at a melting temperature of 800 K. Lastly, molecular dynamics calculations carried out on the Ti7/TiCln structure showed that an increase in temperature results in the broadening of peaks and a decrease in the peak heights. The entropy and Gibbs formation free energy for LiCl (rigid ion and shell models), vii TiCl and TiCl2 (rigid ion model) structures were estimated to determine the influence of temperature on the structures. It was found that the LiCl (shell model) structure is stable at all temperatures and that the TiCl and TiCl2 structures are favoured at lower temperatures (< 500 K). These results provided new insight into understanding the reactions and interactions of titanium clusters with salt mediums in titanium production processes. Moreover, the findings may contribute towards developing alternative ways of titanium production in continuous and less expensive processes. / Royal Society Advanced Fellowship Newton Grant (NA140447); National Research Foundation (NRF) and Titanium Centre of Competence (TiCoC)