http://hdl.handle.net/10386/7 2026-04-14T22:12:51Z 2026-04-14T22:12:51Z Mojapelo, Semola Kabelo http://hdl.handle.net/10386/5408 2026-03-24T01:00:13Z 2025-01-01T00:00:00Z

The design, synthesis, and antitubercular properties of the tri-substituted benzofuran derivatives Mojapelo, Semola Kabelo Tri-Substituted benzofuran derivatives exhibit greater biological activities influenced by natural compounds with highest potency, selectivity, and multifunctionality. Naturally occurring benzofuran with hydroxyl, methoxy, phenyl modification in different position showed antimicrobial, anticancer, antitubercular, and neuroprotective activities. These modification groups can influence lipophilicity, binding affinity and membrane permeability of mycobacterium tuberculosis which impact bioactivity. The aim of the study was to design, synthesise, and evaluate the anti-tubercular properties of the tri-substituted benzofuran derivatives. 5-iodovanillin 1B was made by iodinating commercially available vanillin 1A in a 92% yield. 2-(substituted)-7-methoxybenzofuran-5-carbaldehydes 2A-2E were produced by a Sonogashira cross-coupling reaction with palladium using a variety of acetylenes in a 60–80% yield. 2-(substituted)-7-methoxybenzofuran-5-carbaldehydes (2A-2E) were reduced with sodium borohydride in ethanol at room temperature, producing 2-substituted-7-methoxybenzofuran-5-ylmethanols (3A-3E) in a 60–82% yield. The esterification of the 2-substituted-7-methoxybenzofuran-5-carbaldehydes 3A-3E was catalysed by a Mukaiyama catalyst with several carboxylic acids in dichloromethane at room temperature, producing esters 3A1-3E5 in 40–80% yields. FTIR and NMR spectroscopy were used to characterise each of the synthesised substances. The online platform ADMET3.0 was used to perform the ADMET characteristics of esters 3A1-3E5. The antimycobacterial, cytotoxic, and solubility properties of every synthesised compound were assessed biologically. Several trisubstituted benzofuran derivatives that were synthesised demonstrated antimycobacterium tuberculosis (Mtb H37Rv) activity. For example, compound 3B3 showed good activity in all three media used with less toxicity. Additionally, six compounds (2A, 3A, 3A2, 2B, 3B, and 3B1) showed solubility results ranging between 5-195 μM. Compound 3B showed the best solubility of 195 μM but poor antitubercular activity in all three media used. On the contrary, compound 2A showed promising antimycobacterial activity of 2.02-18.08 μM in two media but had poor solubility of less than 5 μM. Additionally, compound 3A2 demonstrated activity in one medium (7H9/CAS/Glu/Tx), whereas compound 3B1 demonstrated activity in two media (7H9/ADC/Glu/Tw and 7H9/ADC/Glu/Tx). Both compounds displayed comparable outcomes, including good solubility at 50 μM and cytotoxicity at or above 50 μM, respectively. Thesis (M.Sc. (Chemistry)) -- University of Limpopo, 2025

2025-01-01T00:00:00Z Maseko, Sibusiso http://hdl.handle.net/10386/5407 2026-03-24T01:00:20Z 2025-01-01T00:00:00Z

Geology, mineralogy and the occurrence of rare earth elements in the coal deposit at the Uitkomst Colliery (Utrecht Coalfield), Kwazulu-Natal, South Africa Maseko, Sibusiso The Utrecht Coalfield is one of the coalfields of the Main Karoo Basin, which is currently underexplored and there is no information regarding the REEs concentration. Before extracting the REEs, it is significant to examine the distribution and concentration of REEs within the host rock, in this case, coal. The purpose of the study is to explore the mineralogical and geochemical characteristics and occurrence of REEs in the coal deposits at the Utrecht Coalfield (Uitkomst Colliery). Seventeen samples from three different seams (Gus, Alfred, and Fritz) were analysed using petrography, ultimate analysis, proximate analysis, and X-ray diffraction (XRD) analysis. The REEs concentration in the samples was determined by inductively coupled plasma (ICP-MS) techniques, whereas scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) as a direct method and Pearson’s correlation as an indirect method was used to determine the mode of occurrence of the REEs in the samples from the Utrecht Coalfield. The Vryheid Formation in the Utrecht Coalfield consists of sandstones, siltstones, shale, and mudstone, with minor coal seams. The average thickness of the Eland, Fritz, Alfred, and Gus seams is 0.30 m, 0.21 m, 1.21 m, 1.12 m, and 1.26 m, respectively. The samples were dominantly inertinite rich with lesser liptinite and vitrinite macerals and were categorised as medium-rank- C. The Gus, Alfred and Fritz seams had an average ash content of 14.9%, 29.9% and 18.4%, respectively. Few of the samples were low sulphur coals whereas others were medium sulphur coals. The dominant minerals detected by the XRD are quartz and kaolinite with lesser pyrite. The sum concentration of REEs ranged from 23.15 to 173.50 ppm, with an average of 101.43 ppm. The average REEs concentration for the Gus Seam was 79.47 ppm, 120.79 ppm for the Alfred seam, and 137.63 ppm for the Fritz seam. The samples had REEs concentrations higher than that of Worlds and USA Coals except for samples CMB-L1, CB2-L1, CB1-L2, CB2-L2, and CB2-S1. Furthermore, samples CB1-L1, CMB-D, JCBH08B, and JCBH20 had REEs concentrations higher than that of Chinese Coals. The Pearsons’ correlation indicated a mixed inorganic-organic affinity of REEs as shown by the positive correlation. The SEM-EDS analysis in the samples revealed that the REEs have inorganic and organic affinities. The coal-forming environment was weakly reducing to oxidizing, favouring REEs enrichment. The provenance is predominantly a felsic source region, likely a mixture of Archean and post-Archean rocks, including sedimentary sources with granitic, tholeiitic, and alkalic basalt. The Utrecht Coalfield is not promising for REEs extraction. Thesis (M.Sc. (Geology)) -- University of Limpopo, 2025

2025-01-01T00:00:00Z Mabale, Katlego Lennon http://hdl.handle.net/10386/5405 2026-03-21T01:00:43Z 2025-01-01T00:00:00Z

An evaluation of the impacts of urbanisation on Klip River Wetlands degradation, Johannesburg South Mabale, Katlego Lennon Wetlands are among the most productive and vulnerable ecosystems in the world, serving fundamental ecological functions such as water purification and water supply. They are however deteriorating due to urbanisation-induced factors. Urbanisation which is increasing as people are consistently moving from rural to urban areas for better economic opportunities, has been linked with high rates of anthropogenic activities in urban areas, which interact with natural ecosystems, thus putting pressure on wetlands. This study, therefore, evaluated the impacts of urbanisation on Klip River Wetland (KRW), by linking water quality in the wetland and the socioeconomic dynamics within two communities in the city of Johannesburg municipality, i.e. Protea Glen (PG) and Lenasia (LENZ). Water samples were collected seasonally, during wet and dry seasons, at four monitoring sites, to assess the spatial and temporal dynamics in the wetland's physicochemical and biological characteristics. This was done by, employing Multi-parameter, Spectrophotometer, Ion Chromatography (IC), Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES), and Colilert-18, for assessing the physical, chemical, and biological constituents of the water. The water quality assessment was augmented with community perceptions and attitudes on how urbanisation impact local communities (via closed and open-ended questions), as well as evaluating water degradation factors through field observations and key factors from the open-ended responses. Findings indicated that water degradation is occurring during both wet and dry seasons in the KRW and that there are spatial variations in water quality in the monitored areas of the wetland. Ranking in quality from marginal to poor water quality (S3>S1>S2>S4), with sampling site S4 ranking lowest. Results confirms that KRW quality is influenced by parameters such as pH, turbidity, dissolved oxygen (DO), chemical oxygen demand (COD), nitrate (NO3-), magnesium (Mg2+), calcium (Ca2+), manganese (Mn2+), Escherichia coli (E. coli) and total coliforms, which recorded values that did not comply with the South African Water Quality Guidelines (SAWQGs) and the Klip River Catchment’s (KRCs) In-stream Water Quality Guidelines (ISWQGs). The close-ended sociodemographic characteristics of the surveyed community revealed that there were more males (52%) than females (48%), and that there is a relationship between gender and other sociodemographic characteristics such as age, education background, and economic v status. According to the respondents, the most significant influences of urbanisation on KRW include infrastructure (25%), environment degradation (22%), economic activities (19%), and waste disposal (17%), within the communities. These results, together with field observations, linked factors related to urbanisation within the communities that interact with water quality such as traffic congestion, drainage and sewage issues, construction activities, wildfires, mining and industrial activities, and waste. The convergence of these socioeconomic findings, with the water quality assessment, substantiates water quality degradation within the KRW, linked to urbanisation. These findings underscore the urgent need for integrated urban planning, water resource management and conservation strategies to mitigate the adverse effects of urbanisation on KRW. Thesis (M.Sc. (Geography and Environmental Science)) -- University of Limpopo, 2025

2025-01-01T00:00:00Z Mdungwa, Maria Sherly http://hdl.handle.net/10386/5402 2026-03-19T01:00:20Z 2025-01-01T00:00:00Z

Analysing the relationship between crude oil prices and food prices in South Africa between 2010 and 2021 Mdungwa, Maria Sherly This study analysed “the relationship between crude oil prices and food prices in” South Africa. Data for crude oil prices were sourced from the United States (U.S.) Energy Information Administration (EIA), while data for food prices were obtained from the Food and Agricultural Organisation (FAO) for food prices. The analysis was segmented into three periods to account for structural breaks caused by global events: before March 2014, the 2014–2016 Oil Price Collapse, and the onset of the COVID-19 pandemic in February 2020. The bound “co-integration test revealed a long-term relationship between crude oil and” food prices across all segments, achieving the first objective of the study. “The ARDL model was employed to estimate” both “the short-term and long-term” effects of crude oil prices on food prices, fulfilling the second objective. The results showed differential effects of crude oil prices on food prices, with high oil-intensive commodities like meat and dairy showing significant effects. In contrast, low oil-intensive categories like cereal, sugar, and vegetable oil exhibited minimal or delayed effects. The Toda-Yamamoto Granger causality test was applied to determine the causal relationship between crude oil prices and food prices, achieving the third objective. Differential causality was found, with unidirectional causality for sugar, cereal, and meat, and bidirectional causality for vegetable oil during the pandemic period. No significant causal relationship was found for dairy in any segment, despite its high oil intensity, suggesting other mitigating factors in the dairy sector. Overall, the results highlight the varied impact of crude oil prices on different food categories over time, with notable distinctions between high and low oil-intensive food categories. Therefore, policy interventions should focus on managing food price inflation, ensuring energy security, and implementing commodity-specific measures to mitigate the impacts of oil price volatility. Thesis (M. Agricultural Management (Agricultural Economics)) -- University of Limpopo, 2025

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