Prediction of mass spectra using an ab initio approach
- Authors: Novokoza, Yolanda
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/${Handle} , vital:72818
- Description: Access restricted. Expected release date in 2025. , Thesis (PhD) -- Faculty of Science, Chemistry, 2023
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- Date Issued: 2023-10-13
Screening isolation and biological characterization of antibacterial secondary metabolites from macrofauna endemic to the southern African coast
- Authors: Njanje, Idris
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/431944 , vital:72817
- Description: Access restricted. Expected release date in 2025. , Thesis (PhD) -- Faculty of Science, Chemistry, 2023
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- Date Issued: 2023-10-13
The effects of inclusive education policies and administrative circulars on small schools in Namibia
- Authors: Hamutumua, Teopolina Ndilina-Laudika
- Date: 2023-10-13
- Subjects: Inclusive education Namibia Kavango West , Education and state Namibia , Small schools Namibia Kavango West , Right to education Namibia Kavango West , Education Social aspects Namibia Kavango West , Business communication
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/419737 , vital:71671
- Description: The achievement of the right to education for all children in Namibia is fundamentally dependent upon the quality of education provided to these learners irrespective of their social circumstances. Being a sparsely populated region, nearly half of the primary schools in the Kavango West region have fewer than 100 learners; thus, these small schools are regarded as not economically viable. The educational development in rural regions is shaped by limited access to quality, inclusive education and the persistence of low-quality primary education which has resulted in high repetition rates and dropouts. This research is a Critical Discourse Analysis of the education policies and regulations. As a case study, it unpacks Formal Education Circulars on staffing norms and on the closure of small schools, looking at their affordances/constraints on the provision of inclusive quality education for children schooling at small schools in Namibia. Interviews and document analysis were used to gather data. Critical Theory frames the process of ideological critique which, among other things, identifies inequalities and factors that limit human freedom and how such factors can be alleviated. The research asks the question: what are the explicit and implicit underlying realities experienced at one-man schools, which depict the varied situations in which these schools survive? Factors emerging from the study showed that small schools in Namibia are symbols of inequity and the exclusion of educationally marginalised children and their poor communities. Small schools are hardly able to sustain and draw in the resources required to meet the education needs of marginalised communities which fall under the multidimensional poverty index in Namibia. The study found that at the moment there are no deliberate efforts from the Ministry of Education to bring about the necessary changes to small schools, and therefore one-man schools have continued to operate as isolated sections of an inflexible system. It is my contention that deliberate efforts are still needed to improve small schools. Policy decisions that respond to the current challenges faced by one-man schools may be sufficient to bring about noteworthy changes in the operations of one-man schools and these changes could effectively impact the learners learning. The decision to drive change requires a multilayered approach that articulates a clear vision, which is systematically implemented to improve one-man schools in Namibia. , Thesis (MEd) -- Faculty of Education, Primary and Early Chilhood Education, 2023
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- Date Issued: 2023-10-13
The photodynamic therapeutic activities and optical limiting properties of metalated asymmetric porphyrins and corroles
- Authors: Burgess, Kristen Paige
- Date: 2023-10-13
- Subjects: Porphyrins , Corrole , Photochemotherapy , Anti-infective agents , Nonlinear optics , Z-scan technique , Active oxygen , Time-dependent density functional theory , Chemical synthesis
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424490 , vital:72158
- Description: Cancer is a devastating disease that is a leading cause of death worldwide. Despite the available cancer treatments, there is a significant need to improve the therapeutic approach towards this disease. Photodynamic therapy (PDT) is an alternative approach for treating cancer, which requires a photosensitiser, molecular oxygen and light. Although some porphyrin-based derivatives have been approved by the United States Food and Drug Administration (FDA) and other similar agencies elsewhere for photodynamic therapy, their relatively poor photophysicochemical properties mean that there is an ongoing need for new photosensitiser dyes. Singlet oxygen photosensitiser dyes can also be used to treat bacteria that develop antimicrobial resistance in the context of photodynamic antimicrobial chemotherapy (PACT). The main aim of this study was to synthesise and characterise a series of porphyrin dyes with 4-quinolinyl, thien-2-yl and 4-bromo-thien-2-yl meso-aryl groups and their Sn(IV) and In(III) complexes, as well as their corrole analogues. Corroles are contracted macrocycles that have interesting optical properties. The corroles selected for study were found to be difficult to synthesise and purify and had unfavourable photophysicochemical properties and were thus omitted from the PDT and PACT biological applications within this thesis. High- and low-symmetry A4 and ABAB type meso-tetraarylporphyrins porphyrins were synthesised to improve the photophysicochemical properties of the photosensitisers; the utility of these dyes as photosensitisers was studied against the MCF-7 breast cancer cell line for PDT and against Staphylococcus aureus and Escherichia coli for PACT. The thienyl-2-yl rings were introduced to red shift the lowest energy Q band towards the phototherapeutic window, while quaternisation of the nitrogen and sulfur atoms of the 4-quinolinyl and thien-2-yl rings to introduce a cationic nature was explored to improve the bioavailability of the drugs and uptake into the target cell walls for improved efficacy. Heavy Sn(IV) and In(III) central metal ions were introduced to enhance the singlet oxygen quantum yields and limit aggregation through axial ligation. The bromine atoms of the 4-bromo-thien-2-yl meso-aryl rings were also introduced to enhance the singlet oxygen quantum yields of the dyes. Furthermore, the utility of the porphyrin and corrole molecules for optical limiting properties to limit laser radiation to protect optical devices, including eyes, was explored by the z-scan technique. One of the dyes studied, Sn(IV) tetrathien-2-ylporphyrin, that exhibited the most favourable reverse saturable absorbance (RSA) response was embedded into a poly(bisphenol carbonate A) polymer thin film to further explore its suitability for practical applications. , Thesis (MSc) -- Faculty of Science, Chemistry, 2023
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- Date Issued: 2023-10-13
The effect of Cannabis extract on the morphological and metabolic characteristics of various fat depots in diet-induced Obese and STZ-induced male wistar rats
- Authors: Ramlugon, Sonaal
- Date: 2023-04
- Subjects: Rats as laboratory animals , Diabetes in practice , Cannabis -- South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/61282 , vital:70044
- Description: To investigate the potential anti-diabetic/obesity properties of oral cannabis administration in an obese and streptozotocin (STZ)-induced diabetic rat model, as well as an obese rat model, and to determine the mechanism of action, with a focus on the peritoneal and intramuscular fat depots. Experimental Design: Obese and STZ-induced diabetic rats were allocated a high fat diet (HFD) and intraperitoneally injected with STZ to mimic an obese and diabetic state. The rats were then orally administered cannabis extract (CE) of 1.25, 2.5 and 5.0 mg/kg body weight (relative to tetrahydrocannabinol (THC) content) or metformin as a positive control. For the obese rat model, the rats were allocated either a high carbohydrate diet (HCD) or high fat diet (HFD) and orally administered with cannabis extract of 1.25 mg/kg body weight (relative to THC content). Weight, blood and insulin-resistant parameters of the rats were monitored. The mitochondrial to genomic DNA ratio (MT:18S DNA), average adipocyte area of the various adipose tissues, citrate synthase and carnitine palmitoyltransferase 1 (CPT1) enzyme activities of the peritoneal and intramuscular fat were measured. Gene expression levels of uncoupling protein 1 (UCP1), cell-death inducing DNA fragmentation factor alpha like effector-a (Cidea), perilipin, hormone-sensitive lipase (HSL) and mitochondrial transcription factor A (TFAM) were measured in peritoneal fat, intramuscular fat and brown adipose tissue (BAT). Main Findings: Obese and STZ-induced diabetic rat model: Due to the biphasic nature of cannabinoids, cannabis dosage plays an important role in the observed effects. CE1.25 was the only cannabis treatment effective in improving the insulinresistant parameters of the rats unlike the other higher cannabis concentrations (CE2.5 and CE5.0). In the peritoneal fat, CE1.25 increased MT:18S DNA, increased citrate synthase activity, and decreased the average adipocyte area when compared to the STZ group. CE1.25 also induced fat beigeing by upregulating gene expression levels of UCP1 and Cidea. XIX Furthermore, an increase in gene expression levels of perilipin, HSL, and TFAM showed increased fat mobilization and metabolic activity. In the intramuscular fat, CE1.25 also reduced the average adipocytes area. However, a different mechanism of action was observed where CE1.25 did not induce fat beigeing, but instead increased both citrate synthase and CPT1 enzyme activities and gene expression levels of HSL, thereby indicating increased fat oxidation and mitochondrial activity. , Thesis (PhD) -- Faculty of Science, School of Biomolecular and Chemical Sciences, 2023
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- Date Issued: 2023-04
Visualisation processes in teaching patterns and their generalisation: perceptions and experiences from senior phase mathematics teachers
- Authors: Chatima, Simon
- Date: 2022-04-08
- Subjects: Visual learning South Africa Eastern Cape , Mathematics Study and teaching (Secondary) South Africa Eastern Cape , Mathematics teachers South Africa Eastern Cape Attitudes , Sequences (Mathematics) Study and teaching (Secondary) South Africa Eastern Cape , Constructivism (Education) South Africa Eastern Cape , Mathematics teachers In-service training South Africa Eastern Cape , VIPRO MATHS Project
- Language: English
- Type: Master's thesis , text
- Identifier: http://hdl.handle.net/10962/232936 , vital:50039
- Description: This study investigated how senior phase mathematics teachers used visualisation approaches to teach patterns and their generalisation as a result of an intervention programme. This project is an integral component of the VIPRO MATHS Project and one of a number of post-graduate research projects which has a particular focus on visualisation processes in mathematics education in the Southern African region. This case study of Senior Phase mathematics teachers in the Chris Hani West District (CHW) in the Eastern Cape Province of South Africa used a social constructivist theory. The study is grounded within an interpretive paradigm explanatory qualitative method design. It surveyed thirty-seven Senior Phase mathematics teachers from schools in the CHW district to get an idea of how teachers teach patterns and their generalisation, prior to an intervention process. After the survey, nine teachers were purposively selected to take part in an intervention programme. They were then observed (teaching) and interviewed to get their perceptions about what factors enable and/or constrain the teaching of patterns and their generalisation when visualisation approaches were used. The data from the survey questionnaire responses, the lesson observations and the interviews were analysed qualitatively. The findings from the survey questionnaire responses revealed that teachers in CHW district value the use of visualisation approaches, although they used visuals to teach patterns in a way that lacked depth, skill and rigor prior to the intervention. Challenges such as difficulty in keeping abreast with the prescribed syllabus, the lack of resources, time constraints, and the limited knowledge of algebra learners have for successfully transferring pictorial representations to symbolic presentations, emerged from the survey data. This necessitated the need for an intervention which focused on the use of a variety of visual strategies and tools to teach patterns and their generalisation effectively. Data from lesson observations showed that all observed participant teachers used visuals to generate image- related questions and created platforms for lively classroom discussions. The teachers used the generated questions to build on learners’ prior knowledge and to promote learner understanding of pattern dynamics that stem from pictorial representations. The data from the interviews revealed that teachers’ perceptions had drastically changed after the intervention. This was because they were now equipped and empowered to effectively make use of visual strategies that enabled them to: build on learners’ prior knowledge, to manipulate visuals for the purpose of prompting learning, develop cognitive perception in learners, cultivate learner innovation and originality and enhance problem solving techniques. This study concludes that the use of visuals enhanced conceptual teaching of patterns and their generalisation in the observed participants. This has the potential to provide mathematics education researchers and curriculum developers with a strong basis to include visualisation processes and strategies into the design of policy documents and to initiate further research efforts. The implications for the teachers are that learners need to be taught ways to create and interpret visual representations in order to understand the dynamics of transferring a pictorial pattern to its resultant symbolic representation expressing pattern regularity. It is also hoped that the results of this study will be utilised by mathematics subject advisers and teacher training institutions to improve the teaching of patterns and their generalisation. , Thesis (MEd) -- Faculty of Education, Education, 2022
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- Date Issued: 2022-04-08
Exploring Teacher Assessment Practices in The General Education and Training Level in Junior Secondary Schools in Mthatha Education District
- Authors: Novukela, Cawe Sandys
- Date: 2019
- Language: English
- Type: Masters theses , text
- Identifier: http://hdl.handle.net/11260/3460 , vital:43409
- Description: Diabetes mellitus is one of the largest and most important public health emergencies of our time that has resulted in human suffering and huge financial implications for organisations, governments and individuals (IDF Atlas, 2015). Furthermore there is growing evidence that a number of employees are overstretched in their work environments and this has resulted in stress and burnout (McCormack and Cotter, 2013). This study investigated the effects of diabetes mellitus on burnout among WSU employees as well as the prevalence of diabetes mellitus and burnout. A mixed method research design using quantitative and qualitative approaches was employed in order to explore the effects of diabetes on burnout as well as the prevalence of diabetes and burnout at WSU. A cross-sectional survey was used to gather quantitative data and semi-structured interviews were used for the qualitative data collection. A total number of 169 participants were involved in this study. This included 154 participants and 15 participants who were selected for the quantitative and qualitative respectively using random sampling technique and purposive sampling method. The quantitative data was analysed using Stata version 13. The study findings indicated that the prevalence of diabetes at WSU was 16% and 57% participants were burned out. It was further found that the majority of participants (58%) who were diabetic also suffered from burnout. The relationship between diabetes and burnout was found to be significant. Qualitative data analysis involved coding data and analysing the emerging themes to form the basis of the findings. The results of the study found an emerging problem of high level of burnout and also a significant number of employees who were diabetic. A combination of these two conditions poses a challenge to the continued uninterrupted functioning of WSU. It is recommended that the university should educate its employees about diabetes and burnout as well as create an environment that promotes healthy lifestyle. A model has been developed that could help deal with diabetes and burnout. , Thesis - Faculty of Health Sciences, 2019
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- Date Issued: 2019
Interaction of catechol O-methyltransferase with gold and silver nanoparticles
- Authors: Usman, Aminu
- Date: 2018
- Subjects: Parkinson's disease , Methyltransferases , Catechol , Nanoparticles
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/61818 , vital:28063 , DOI https://doi.org/10.21504/10962/61818
- Description: Catechol O-methyltransferase (S-adenosyl-Z-methionine: catechol O-methyltransferase; COMT; EC 2.1.1.6) is a ubiquitous enzyme that catalyses the transfer of a methyl group from the cofactor, S-adenosyl-Z-methionine (SAM) to a hydroxyl group of endogenous and exogenous catechol-containing moieties. The physiological role of this enzyme is the methylation and thereby inactivation of the catechol-containing bio-active and bio-toxic compounds, including catechol-neurotransmitters, catechol-estrogens and catechol-containing drugs. Activity of this enzyme is implicated in the treatment of Parkinson’s disease and is associated with other diseases including breast cancer and an array neuropsychological disorders, such as schizophrenia. This thesis explores the use of gold and silver nanoparticles (NPs) (AuNPs and AgNPs) to inhibit the catalytic activity of mammalian COMT. Because of its accessibility and availability, we initially investigated bovine soluble COMT (BSCOMT) from liver tissue. Bioinformatic analyses and structural modeling revealed high (>90%) sequence similarity between BSCOMT and human soluble COMT (HSCOMT). BSCOMT was partially purified to 7.78 fold, 1.65% yield and had a specific activity of 0.052 U/mg. It had pH and temperature optima of 8.5 and 40oC, respectively. The Km, Vmax, Kcat and Kcat/Km towards esculetin methylation were respectively 1.475±0.130 pM, 0.0353±0.001 pmol/ml/min, 1.748 x 10-2±5.0x10-4 min-1 and 1.18x10-2 M-1. min-1. HSCOMT was expressed in Escherichia coli BL21(DE3) which showed optimal activity for esculetin methylation at pH and temperature of 7.0 and 30°C, respectively. It was purified to 5.62 fold, 22.6% yield with a specific activity of 3.85 U/mg. HSCOMT kinetic plots, upon incubation of the reaction mixture at 30°C for 5 min before addition of SAM was hyperbolic with Km, Vmax, Kcat and Kcat/Km values of 1.79 pM, 0.412 pmol/ml/min, 2.08 min-1 and 1.165 M-1. min-1, respectively. AuNPs and AgNPs showed a concentration dependent inhibition of HSCOMT activity upon increasing the 5 min incubation time to 1 h. Interestingly, HSCOMT kinetics, with 1 h incubation at 30°C, showed a sigmoidal curve, as well as increased activity. Incubation of the reaction mixture in the presence of 60 pM AuNPs and/or AgNPs for 1 hreversed the observed sigmoidal to a hyperbolic curve, with kinetic parameters comparable to those of 5 min incubation. SDS-PAGE analyses of HSCOMT after the kinetic experiments showed the enzyme incubated for 5 min as a monomer, while that which was incubated for 1 h migrated substantially as dimer. However, the HSCOMT incubated for 1 h in the presence of 60 pM AuNPs and/or AgNPs migrated as a monomer. This indicated that the extension of the incubation period allowed the dimerization of HSCOMT, which exhibited sigmoidal kinetics and higher activity. The presence of NPs impeded the HSCOMT dimerization which decreased the activity. Varying the concentration of SAM suggested that SAM had an allosteric modulatory effect on HSCOMT. Absorption spectroscopy indicated adsorption of HSCOMT on the gold and silver NP surfaces and the formation of NPs-HSCOMT corona. Fluorescence spectroscopy showed that the interaction of HSCOMT with both gold and silver NPs was governed by a static quenching mechanism, implying the formation of a non-fluorescent fluorophore-NP complex at the ground state. Further fluorometric analyses indicated that both gold and silver NPs had contact with Trp143; that the interactions were spontaneous and were driven by electrostatic interactions. Fourier transform infrared spectroscopic studies showed the adsorption of HSCOMT of the NPs surfaces to cause relaxation of the enzyme’s B-sheet structures. Molecular docking studies indicated involvement of largely hydrophilic amino acids, with the interacting distances of less than 3.5A. These findings signify the potential of nanotechnology in the control of COMT catalytic activity for the management of the COMT-related disorders. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2018
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- Date Issued: 2018
Composition and fate of triclosan in the sludge from wastewater treatment in Grahamstown, South Africa and Tiaret, Algeria
- Authors: Ncube, Mbonisi
- Date: 2017
- Subjects: Sewage sludge , Sewage Purification South Africa Grahamstown , Sewage Purification Algeria Tiaret , Sewage sludge as fertilizer , Anti-infective agents
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/65156 , vital:28697
- Description: Physicochemical properties such as pH, specific surface area (SSA), cationic exchange capacity (CEC), loss on ignition (LOI), pathogens, plant nutrients (nitrates, ammonium and phosphates), and heavy metals (manganese, copper, lead and cadmium) were determined for sewage sludge from Grahamstown and Tiaret. The values obtained were log transformed thereafter a t-test at 5 % level of significance was used to test for the difference in each parameter for both sludges. The pH of sludge was determined in 1:3 water, 16 water, 1:3 0.01 M calcium chloride and 1:3 1 M potassium chloride. The pH for Grahamstown and Tiaret sludge were in the ranges of 6.66-7.11 and 7.88-8.18 respectively. The SSA values for Grahamstown and Tiaret were 218 ± 108 and 261 ± 99.9 m2/g, and the CEC values were 119 ± 2.09 and 136 ± 6.03 mEq/100, respectively. The LOI values obtained were 1.33 ± 0.03 and 1.48 ± 0.11 % for Grahamstown and Tiaret, respectively. E. coll and heterotrophic bacteria were the pathogens determined, and were extracted from sludge using sterile saline and nutrient broth. The concentration of E. coll in Grahamstown and Tiaret sludge were 468 ± 7.63 and 7769 ± 1268 CFU/g d.w and for heterotrophic bacteria were 1.17x109 ± 7.42x108 and 1.43x109 ± 9.11 x108 CFU/g d.w. For Grahamstown sludge, the concentration of nitrates, ammonium and phosphates were 55.61 ± 55.20 mg/g d.w, 6.60 ± 2.36 mg/g d.w and 1.40 ± 0.30 mg/g d.w, respectively. For Tiaret sludge, the concentration of nitrates, ammonium and phosphates were 2.56 ± 2.90 mg/g d.w, 0.64 ± 0.45 mg/g d.w and 0.24 ± 0.19 mg/g d.w, respectively. The concentration of Mn, Cu, Pb and Cd in Grahamstown sludge were 423 ± 101, 353 ± 92, 40.2 ± 20 and 0.0 mg/kg d.w respectively, and for Tiaret sludge, the corresponding concentrations were 358± 295, 549±50, 1427± 1352 and 1.54 ± 0.61 mg/kg d.w. Sewage sludge was found to contain Triclosan, and solubility studies of the compound were conducted using sodium deoxycholate and sodium lithocholate. The apparent solubilities and rate constants indicated in brackets of TCS at 37 °C were 35.4 ± 1.21 mg/L (1.28 ± 0.36 Hr-) and 14.4 ± 0.34 mg/L (0.99 ± 0.17 Hr-) in sodium lithocholate and sodium deoxycholate, respectively. The apparent solubilities and rate constants indicated in brackets of TCS at 15 °C were 32.3 ± 0.88 mg/L (2.16 ± 0.80 Hr-) and 14.2 ± 0.39 mg/L (1.02 ± 0.17 Hr-) in sodium lithocholate and sodium deoxycholate, respectively. Triclosan was extracted from sludge using 1 g/L sodium deoxycholate and the determined concentration were 142 ± 33.5 gg/g d.w for Grahamstown sludge and 0-12 gg/g d.w for Tiaret sludge. Finally plant growth studies were conducted on radish and garden cress plants using Grahamstown sludge at 0, 20, 40, 80 and 100 % treatments. Statistical analysis (t-test and Kruskal-Wallis) at 5 % level of significance was done to compare growth parameters between control and different sludge treatments. For radish plants, the values for plant height, root length, number of leaves, leaf length and dry mass were 28.4-80-7 mm, 4.3-44.7 mm, 3.3-17.0 mm, 2.3-4.0 leaves and 6.3-15.3 %, respectively. For garden cress, the values for plant height, root length, number of leaves, leaf length and dry mass were 13.7-25.0 mm, 7.7-20.3 mm, 5.7-8.3 leaves, 3.0-8.3 mm and 8.8-15.0 %, respectively. Twenty percent (20 %) sludge treatment gave the best results in radish and garden cress plants with respect to plant height, root length, number of leaves and dry mass. Triclosan concentration in radish and garden cress plants was below the detection limit of 32.4 gg/g d.w. , Thesis (MSc) -- Faculty of Pharmacy, Pharmacy, 2017
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- Date Issued: 2017