List of Titles

Quinolone-Pyrazinamide Derivatives: synthesis, characterisation, in silico ADME analysis and in vitro biological evaluation against Mycobacterium tuberculosis

- Rukweza, Kudakwashe Gerald

Authors: Rukweza, Kudakwashe Gerald
Date: 2023-10-13
Subjects: Quinolone antibacterial agents , Mycobacterium tuberculosis
Language: English
Type: Academic theses , Master's theses , text
Identifier: http://hdl.handle.net/10962/390901 , vital:68596
Description: Tuberculosis is one of the leading causes of death worldwide caused by an infectious species, Mycobacterium tuberculosis (Mtb). Some of the factors that contribute to the prevalence of this disease include the complexity of diagnosis, prolonged period of therapy, side effects associated with current TB drugs, the prevalence of resistance against the current treatment options and a high incidence of co-infection with HIV/AIDS. Thus, there is a need for new alternative drugs to provide safer and shorter treatment therapy options that are not susceptible to the development of drug resistance. In this project, we focus our attention on the quinolone pharmacophore. Quinolones are currently used as alternative options in the treatment of resistant strains of Mtb. Previous work pertaining to quinolone-isoniazid hybrid compounds showed promising in vitro activity against the H37Rv strain of Mtb and served as the inspiration to pursue this project. The journey commenced with the synthesis of quinolone-pyrazinamide hybrid compounds (Figure 3.1). These compounds were synthesised, through the attachment of the quinolone and the pyrazinamide entity through a hydrazine linker. The synthesised compounds were purified, and their structural identity confirmed using common spectroscopic techniques including 1H and 13C NMR, infra-red (IR) and mass spectrometry. In vitro biological assays were performed by testing for the activity against the H37RvMA strain of Mtb. The bioassays were performed in triplicates to ensure the accuracy of the results. Moxifloxacin and isoniazid were tested as control compounds. Finally, the resultant compounds were profiled in silico for physicochemical and ADMET properties using open access software SwissADME. All the synthesised compounds 3.8a-f showed no activity against H37RvMA. In most cases, the resulting compounds showed minimal to no activity (MICs ≥ 57.3 μM) in all three media. During the in vitro studies, the compounds showed significant precipitation in the media over time suggesting poor aqueous solubility. The SwissADME analysis of these compounds indicated poor solubility in aqueous media, which is likely linked to their molecular size and complexity. Despite poor aqueous solubility, compounds 3.8a-f showed acceptable physicochemical properties and ADME parameters. No PAINs (Pan-assay interference compounds) were observed. Minimal to no interaction with CYP enzymes were predicted. Most of the compounds were compatible with the Lipinski’s rules of five. , Thesis (MSc) -- Faculty of Science, Chemistry, 2023
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Date Issued: 2023-10-13

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Evaluation of the effectiveness of small aperture network telescopes as IBR data sources

- Chindipha, Stones Dalitso

Authors: Chindipha, Stones Dalitso
Date: 2023-03-31
Subjects: Computer networks Monitoring , Computer networks Security measures , Computer bootstrapping , Time-series analysis , Regression analysis , Mathematical models
Language: English
Type: Academic theses , Doctoral theses , text
Identifier: http://hdl.handle.net/10962/366264 , vital:65849 , DOI https://doi.org/10.21504/10962/366264
Description: The use of network telescopes to collect unsolicited network traffic by monitoring unallocated address space has been in existence for over two decades. Past research has shown that there is a lot of activity happening in this unallocated space that needs monitoring as it carries threat intelligence data that has proven to be very useful in the security field. Prior to the emergence of the Internet of Things (IoT), commercialisation of IP addresses and widespread of mobile devices, there was a large pool of IPv4 addresses and thus reserving IPv4 addresses to be used for monitoring unsolicited activities going in the unallocated space was not a problem. Now, preservation of such IPv4 addresses just for monitoring is increasingly difficult as there is not enough free addresses in the IPv4 address space to be used for just monitoring. This is the case because such monitoring is seen as a ’non-productive’ use of the IP addresses. This research addresses the problem brought forth by this IPv4 address space exhaustion in relation to Internet Background Radiation (IBR) monitoring. In order to address the research questions, this research developed four mathematical models: Absolute Mean Accuracy Percentage Score (AMAPS), Symmetric Absolute Mean Accuracy Percentage Score (SAMAPS), Standardised Mean Absolute Error (SMAE), and Standardised Mean Absolute Scaled Error (SMASE). These models are used to evaluate the research objectives and quantify the variations that exist between different samples. The sample sizes represent different lens sizes of the telescopes. The study has brought to light a time series plot that shows the expected proportion of unique source IP addresses collected over time. The study also imputed data using the smaller /24 IPv4 net-block subnets to regenerate the missing data points using bootstrapping to create confidence intervals (CI). The findings from the simulated data supports the findings computed from the models. The CI offers a boost to decision making. Through a series of experiments with monthly and quarterly datasets, the study proposed a 95% - 99% confidence level to be used. It was known that large network telescopes collect more threat intelligence data than small-sized network telescopes, however, no study, to the best of our knowledge, has ever quantified such a knowledge gap. With the findings from the study, small-sized network telescope users can now use their network telescopes with full knowledge of gap that exists in the data collected between different network telescopes. , Thesis (PhD) -- Faculty of Science, Computer Science, 2023
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Date Issued: 2023-03-31

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A Pedagogy of Love: reflections on 25 years of informal vocational education and training practices in the commercial fishing industry in South Africa

- Ferguson, Robin Anne

Authors: Ferguson, Robin Anne
Date: 2023-03-29
Subjects: Uncatalogued
Language: English
Type: Academic theses , Doctoral theses , text
Identifier: http://hdl.handle.net/10962/366189 , vital:65841 , DOI https://doi.org/10.21504/10962/366189
Description: This thesis is a reflection of informal vocational education and training (IVET) practices conducted by the Researcher in the commercial fishing industry between 1995-2021. Fourteen interventions took place during this time which involved several hundred sea-going employees who are disadvantaged by low levels of literacies and low/no Internet Computer Technology connectivity. The Production Programme was chosen as the focus of study and draws upon the influence of the other thirteen programmes. The purpose of the Production Programme was to teach technical fish processing skills to the production management teams and factory hands who work in the factories on board the vessels. The programme ran for five years and evolved through three distinct generations. At the heart of this work lies the question: ‘What made these programmes successful?’ This is an intra-programmatic study and seeks to identify the pedagogical practices which promoted or confounded the efficacy of the Production Programme; and based upon this understanding how such programmes could be improved, transferred, and taken to scale. These questions are both descriptive and explorative in nature. IVET is regarded as training which takes place outside of the formal South African National Qualifications Framework. This work is relevant because approximately 80% of sea-going staff neither finish school, nor get the opportunity of Post School Education and Training by going to a university, a technical institution, or a community college. This statistic is reflected in the general population (Department of Higher Education and Training [DHET], 2022). There is a fine line between being employed and unemployed for people working at this level in the formal economy which makes this project relevant to youth or persons who are ‘not in employment, education or training’ too. This means that for most South African adults IVET presents a significant opportunity for post-school education. Therefore, it is important to answer the questions raised above to rapidly improve inclusion of the majority of South Africans into meaningful education which improves livelihoods. The Theory of Practice Architectures (TPA), from the collection of social-material practice theories, is the conceptual framework for this thesis. The smallest unit of analysis of TPA are practices which may be ‘sayings/thinkings’, ‘doings’, or ‘relatings’. These practices bundle together into practice arrangements and form practice architectures. The reason that TPA was chosen was that practices were the only data available as we (learners, managers, facilitators, and me) knew what we had said/thought or done, and we were aware of the relationships between us over the years as the fourteen interventions played out. Under conventional research circumstances data would be collected in real time, however in this project, most of the data is historical. In addition to the fundamental building blocks of TPA, the theory is embedded in a Theory of Education. There have also been contemporary enhancements to the TPA which were significant to this study, for example, the Ecologies of Practices, a Trellis of Practices which Support Professional Learning, Middle Leadership, Travelling Practices, and moves towards transformative or transgressive education using the TPA in IVET. This is empirical, qualitative research and an ethnographic case study was chosen as the research design which is a methodology particularly suited to answering both descriptive and explorative questions. Nine methods for data collection were used, namely an historical reflective narrative; two focused-group interviews; three individual interviews; four Whatsapp videos; one WhatsApp voice note; two mobisodes; ten questionnaires; 29 documents; and 16 photographs. Because this data was collected under Covid-19 pandemic conditions, two conceptions were employed to guide the generation of data under these uncertain and constrained conditions. These were firstly, the ‘methodology of chance’ which allowed for a ‘methodological agility’; and secondly, the idea of ‘information power’ which is helpful in deciding on how much data is enough. In order to be explicit concerning a key research activity, the approach and method used to review the literature is explicated. Key practices were identified in the data set and described; and then the data was analysed using heuristics provided by TPA theorists. Seven Tables of Invention were used to synthesise the data arising from these practices. An eighth Table of Invention was used to synthesise all the practices and practice arrangements characterised; and to indicate how these evolved over time and space. The data description and analysis is supported by eight Analytic Memos, a comprehensive Data Code Table and a hyperlink to a data repository which provides access to oral and video material. The findings distinguished five key practices and practice arrangements which were: Practices of the Creation of Courseware; Practices of Teaching and Learning; Practices of Assessment; Practices of Love; Practices of Management. The thesis title is reflective of the impact which love has upon the pedagogical process of IVET. Based upon the analysis and synthesis of the corpus of data, practices which either promoted or confounded the Production Programme became visible; it is these insights which inform future improvements to similar programmes. Emanating from these findings, two overarching practice architectures (PA) were identified which restrained the Production Programme in the same manner that the banks of a river restrain a river, and yet simultaneously, are changed by the river over time. These are the PA of Methodology and Methods and the PA of Maturing Ecologies of Practices. The inferences drawn from the data were achieved through the use of deductive, inductive, and abductive reasoning. My claim to new knowledge is a lamination of a practical contribution on one side of the coin, and a theoretical contribution on the other side of the coin. The PA of Methodology and Methods provides a practical mechanism to create, deliver and assess IVET. This is done by explicating the three practice architectures which constitute the overarching PA of Methodology and Methods which are, the PA of Informality; the PA of Range, and the PA of Relationality. An IVET programme constitutes Ecologies of Practices. The theoretical conception of the overarching PA of Maturing Ecologies of Practices provides a conceptual tool which enables the transferring and scaling of IVET programmes. It does this by providing theoretical indicators to establish the ‘state’ of an IVET programme as it matures over time from a pioneer state to a settler state. An IVET educator can then work towards creating a PA which is conducive for a mature ecologies of practices to form; and the programme can then be transferred and/or taken to scale, if this is desirable in the particular context. The power of my claim to new knowledge does not lie on one side or the other of the coin, but in the lamination of the practical and theoretical contributions put to use in the service of IVET. This thesis concludes with a number of theoretical and practical recommendations which are loosely grouped according to ‘sayings/thinkings’, ‘doings’ and ‘relatings’ in deference to the value of TPA to this thesis. An urgency is conveyed in these recommendations as there is an immediate need to improve the livelihoods of ordinary South Africans. One of the ways of doing this is through informal ‘education for living well’ which contributes to a ‘world worth living in’. , Thesis (PhD) -- Faculty of Education, Education, 2023
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Date Issued: 2023-03-29

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Exploring aspects of Community of Inquiry (CoI) in Afrophilia learning processes for transformative education using an Afrophilic ‘Philosophy for Children’ approach: a case of Sebakwe resettlement primary schools in the Midlands Province of Zimbabwe

- Bhurekeni, John

Authors: Bhurekeni, John
Date: 2023-03-29
Subjects: Culturally relevant pedagogy Zimbabwe , Curriculum change Zimbabwe , Philosophy Study and teaching (Elementary) Zimbabwe , Critical thinking , Decolonization Zimbabwe , Technology Political aspects , Representation (Philosophy)
Language: English
Type: Academic theses , Doctoral theses , text
Identifier: http://hdl.handle.net/10962/366178 , vital:65840 , DOI https://doi.org/10.21504/10962/366178
Description: This study focused on investigating and developing an Afrophilic orientation to a sociocultural approach to philosophy for children. The main aim was to foster a critical and generative approach to considering the heritage-based curriculum foundations of Zimbabwean primary schools, focusing on Sebakwe resettlement primary schools (the case study area). Afrophilia foundations in the study are regarded as “the discourses that are the medium of philosophical reflexion” (Rettova, 2004, p. 4) in each African society. As articulated in the study, such discourses include African proverbs, poems, stories, music, and folktales which are useful in the initiation of philosophical engagements with children in a community of inquiry approach. A community of inquiry is a framework that reflects a collaborative-dialogical approach to teaching and learning. Curriculum reviews in postcolonial Zimbabwe have revealed an unconscious misalignment of the Zimbabwean education system's philosophical underpinnings because it has continued to align itself with imperial British colonial philosophy, which contradicts the country's developmental needs (Presidential Commission of Inquiry into Education and Training [CIET], 1999, Zimbabwe Ministry of Primary and Secondary Education [MoPSE], 2014). The philosophical misalignment is an extension of the colonial history of Zimbabwe showing that vestiges of colonial rule still shape the education sector. This leaves the education system focusing mainly on abstracted concepts with continued marginalisation of local cultures, discourses, and knowledge. Consequently, it leaves Zimbabwe together with other postcolonial education systems with the task of dealing with the phenomenon of colonial continuity. One implication of these colonial continuities, is learner disinterest in learning, which affects the educational process negatively, affecting the learning of critical reflexive thinking, an issue which I have observed in the Sebakwe resettlement schools involved in this study where I have been teaching for 15 years. To address, this, the study sought to answer the following questions: What historical and contemporary barriers are affecting the promotion of a culture of learning in Zimbabwean resettlement primary schools, particularly as they relate to learners' underdevelopment of critical reflexive thinking skills? In addition, How can the Philosophy for Children Afrophilia curriculum intervention promote a culture of learning in Sebakwe resettlement primary schools that is oriented toward the development of critical reflexive thinking skills in children? In approaching the research questions, I applied postcolonial and decolonisation theory, sociocultural learning theory and curriculum theory aimed at transformative change, that is oriented towards achieving a more contextually oriented approach to teaching and learning, and a paradigm of ‘learning as connection’ (Lotz-Sisitka & Lupele, 2017; Shumba, 2017). This has been identified as a ‘missing’ discourse in mainstream educational quality discourses in southern Africa (Lotz-Sisitka & Lupele, 2017). Furthermore, to create space for curriculum development using multi-actor groups in a community of inquiry, I used decolonial research methodologies in the data generation process. The study is constituted as an interventionist case study, and I applied a four-stage process comprising document analysis, workshops, participant observations involving children between 8-11 years, and reflective interviews with parents, educators and children as instruments for data gathering. I also used process-based analytical tools developed in Philosophy of Children research to analyse the processes of critical reflexive thinking development that emerged from the Philosophy for Children pedagogy involving ten lessons which I facilitated, and videorecorded. Moreover, I used postcolonial and decolonial discourse analysis to provide the broader analytical insights that informed the interpretations of the lesson analysis data from the perspective of the research problem that I address across the research project. This PhD is produced as a PhD by publication, which involves publishing of papers, and orientation to, and interpretation of the papers. The main findings of this study are reported in articles that I prepared for publication, three of which have already been published (see Appendices A1, A4 and A5), and four which have been submitted for publication (A2, A3, A6, A7) with some already at an advanced stage of finalisation via review. The conceptual paper (A1) that served as the foundation for the publication journey revealed that, in addition to the weight of cultural technologies of domination, the curriculum is shaped by the paradox of a superficial interpretation of unhu/ubuntu educational philosophy. As a result, the curriculum becomes disconnected from the learners' real-world experiences. The second paper (A2), which focuses on why Zimbabwe needs the Philosophy for Children approach with a sociocultural medley, unveils Zimbabwe's complex decolonial curriculum reforms and their many contradictions and paradoxes. However, it also emerged that the approach used in this study empowers teachers, is relevant to the emerging constellation of practices in the Sebakwe resettlement, and influences power sharing beyond teacher-child relationships. The third paper (A3), based on children’s philosophy for children practice, defends the study’s decision to bring children’s heritage and cultural lens to bear on curriculum and pedagogical praxis. In essence, the article explores a synergy between philosophy for children and the Zimbabwean heritage-based educational curriculum, serving to enrich both. The fourth paper (A4) makes the case that philosophy for children could be a viable pedagogy for transformative education, and it provides evidence-based implementation of a context-based philosophy for children. According to this paper, the approach is effective in strengthening strong community relationships, instilling pride in local heritage, and advancing curriculum transformation. The fifth paper (A5) focusses on the approach's implications for teachers' roles, practices, and competencies. Six dimensions of teacher roles, practices, and competences surfaced, including the role of the teacher as a decoloniser and pedagogical innovator, among others. The sixth paper (A6), influenced by the previous papers' findings, focused on decolonisation and improving learning opportunities for children in the Sebakwe area using the philosophy for children approach. This paper's data depicts a ‘third space’ in which learners consolidate their cultural capital and curriculum content into their own meaning construction. The implication is that schools become neutral sites that improve learners' interdependence and inclusivity while also taking contextual realities into account. The findings of the seventh and final paper (A7) presented in this write-up advance the idea that a Philosophy for Children approach with a sociocultural medley influences an ethics of care by demonstrating how Afrophilia experiences influence a new path to wildlife conservation and sustainability. The study highlights that integrating Philosophy for Children and Afrophilia foundations of knowledge into the school curriculum promotes critical reflexive thinking skills, helps to address real-life problems and adds relevance to the curriculum. The study further shows that the integration of philosophy for children in the advancement of curriculum transformation in Zimbabwe is a successful formative interventionist approach in the resettlement schools that are characterised by a critical shortage of teaching and learning resources. In essence, the research opens an understanding that curriculum transformation and decolonisation are context-based and multi-actor processes, as showcased in the experiences of parents, teachers, education inspectors, and children in this study. Furthermore, this study posits that situating curriculum decolonization and transformation within unhu/ubuntu dialectical rationality and advancing diversity in reasoning necessitates deeper engagement with heritage-based curriculum and provides teachers with appropriate agency to modify and adapt their pedagogies in alignment with the learners' life world. According to the study, this emerged as a rational possible solution to the problem of curriculum decontextualisation. Curriculum decontextualisation as highlighted in the study via the problem of colonial continuity mentioned above, appears to be further influenced by the emphasis on examination assessment scores which seem to widen the gap between the adult and child worlds, as well as the gap between contextual realities and [curriculum] examination content. Overall, the study offers an approach that can deepen an unhu/ubuntu foundation for the heritage-based curriculum reform in Zimbabwe, and strengthen the learning of children in the resettlement schools, where the case was explored. Implications for further research are elaborated, as are possible implications for policy and practice. , Thesis (PhD) -- Faculty of Education, Education, 2023
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Date Issued: 2023-03-29

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Integrating music and mathematics for connecting across multiple constructs of fractional understanding: an RME task design journey

- Lovemore, Tarryn Shirley

Authors: Lovemore, Tarryn Shirley
Date: 2023-03-29
Subjects: Communities of practice , Interdisciplinary approach in education , Fractions , Mathematics Study and teaching , Music in mathematics education , Number line
Language: English
Type: Academic theses , Doctoral theses , text
Identifier: http://hdl.handle.net/10962/366200 , vital:65842 , DOI https://doi.org/10.21504/10962/366200
Description: Two South African curricular aims: appreciating creativity in mathematics and developing conceptual understanding, motivated this study. Negative views towards mathematics and challenges in teaching and learning fractions at primary school level are reported in literature, with the part-whole construct of fractions often the sole teaching focus. Despite challenges in curriculum integration (high demands on teachers and diluting disciplines), benefits, such as motivation and creative thinking, are noted. I recognised music-mathematics integration as an opportune context for designing tasks to support learners in moving flexibly between the fraction as ratio, fraction as measure and part-whole constructs. Guided by Realistic Mathematics Education principles, I embarked on a participatory dual-design experiment in task design, grappling within three micro-Communities of Practice (micro-CoPs) and across two planes: the Design-Theorising Plane and the Grounded-Practice Plane. In the Design-Theorising Plane, I worked with my two doctoral supervisors, grappling with design obstacles and finding resolutions. COVID-19 restrictions shifted our meetings to online platforms, allowing documentation and analysis of the task design process through recording functions. In the Grounded-Practice Plane, I worked within two separate micro-CoPs, both at independent schools (eight and two participating teachers respectively). Data on the teachers’ interrogation and implementation of the designed tasks were obtained via formal and informal interviews. Their reflections informed ongoing adaptations to the task design. Data were analysed in a matrix I designed and via NVivo coding. Findings include both the product of the task design journey (eight music-mathematics lessons, resources, and representations) and the process (ten groupings of Obstacle-Resolution Cycles). Three key questions (relating to music-mathematics fidelity; to task simplification for implementation; and to appropriate music-mathematics representation) were used in addressing each Obstacle-Resolution Cycle. Designing tasks to teach the part-whole construct of fractions was relatively straightforward, but designing tasks to teach the fraction as ratio and fraction as measure constructs was more challenging. These constructs could not be conflated by superimposing the music and mathematical linear representations. Aligning them, however, allowed for moving flexibly between the constructs. The teachers reported that the integrated music-mathematics tasks and supporting resources enhanced their learners’ fractional problem-solving abilities, simultaneously promoting more positive learner dispositions towards mathematics. , Thesis (PhD) -- Faculty of Education, Education, 2023
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Date Issued: 2023-03-29

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Leveraging a peer-learning community and expert community members in the integration of indigenous knowledge into the learning and teaching of Grade 10 Chemistry on the rate of reactions

- Simasiku, Fredrick Simataa

Authors: Simasiku, Fredrick Simataa
Date: 2023-03-29
Subjects: Uncatalogued
Language: English
Type: Academic theses , Doctoral theses , text
Identifier: http://hdl.handle.net/10962/366211 , vital:65843 , DOI https://doi.org/10.21504/10962/366211
Description: The integration of indigenous knowledge (IK) in science teaching in Namibia is part of the transformation agenda that hopes to revitalise and make science accessible and relevant to learners’ everyday life experiences. However, there seems to be contradictions between the intended curriculum, the enacted curriculum and the attained curriculum. This disjuncture is exacerbated in part by the fact that science teachers seem to be struggling to be cultural knowledge brokers. It is against this backdrop that this formative interventionist study sought to leverage a peer-learning community and expert community members in the integration of IK into the learning and teaching of Grade 10 Chemistry on the rate of reactions. To achieve this, we mobilised the indigenous technologies of preserving and pounding Mahangu and making Oshikundu to mediate learning of the rate of reactions. The study was guided by the broad overarching research question: How does a peer-learning community and expert community members leverage the integration of indigenous knowledge into the learning and teaching of Grade 10 Chemistry on the rate of reactions? In this study, I used two complementary paradigms, viz. the transformative research paradigm and the indigenous research paradigm. Within these paradigms, I employed a qualitative case study research design using the community of practice and participatory action research as research approaches. Five Grade 10 Chemistry teachers from three schools in the Ohangwena region were involved in this study. Data were generated through semi-structured interviews, co-analysis of curriculum documents, workshop presentations and discussions, practical demonstrations, participatory observation, lesson observation, stimulated recall interviews, and participants’ reflections. Vygotsky’s sociocultural theory and Shulman’s Pedagogical Content Knowledge (PCK) were employed as theoretical frameworks in this study. Additionally, within PCK, Mavhunga and Rollnick’s Topic-Specific Pedagogical Content Knowledge components were used as an analytical framework. I used an inductive-deductive approach to data analysis to come up with sub-themes and themes. The main finding of this study revealed that leveraging a peer-learning community and the expert community members (ECMs) empowered the Chemistry teachers involved in this study to be cultural knowledge brokers and their understanding of how to integrate IK in their teaching improved. Both their subject matter knowledge and pedagogical content knowledge improved through co-developing and enacting exemplar lessons that integrated IK from the expert community members as well as from their own environments. A main insight of this study is that Chemistry teachers should seek opportunities to create peer-learning communities that engage with expert community members who are the custodians of the cultural heritage. The study also shows that this approach will support them to become better cultural knowledge brokers and help their learners bridge the divide between school science and what they have learnt in their homes or community. , Thesis (PhD) -- Faculty of Education, Education, 2023
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Date Issued: 2023-03-29

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'ORPHEIOI HYMNOI' The generic contexts of the Orphic Hymns

- Malamis, Daniel Scott Christos

Authors: Malamis, Daniel Scott Christos
Date: 2022-10-14
Subjects: Orphic hymns , Poetics Early works to 1800 , Hymns, Greek (Classical) History and criticism , Literary form
Language: English
Type: Academic theses , Doctoral theses , text
Identifier: http://hdl.handle.net/10962/327177 , vital:61088 , DOI 10.21504/10962/327177
Description: Uncertainty surrounds the circumstances of Orphic Hymns’ composition and their intended use. Their author has substituted their own identity for that of the mythological poet and there is no certain reference to the extant collection in any ancient source. They are, in this sense, decontextualised. This study aims to make a contribution to the ongoing debate concerning the hymns’ composition, and the original function they might have served, through an analysis of their poetic and generic contexts. Following a detailed survey of scholarship on the hymns, I reflect first on the collection as a unified text, the constitutive parts of the individual hymns and the methods they employ for addressing, describing and praying to the gods. I then study a select group of stylistic features that the hymns prominently display: their use of phonic effects, including etymological figures, of antithesis and symmetrical patterning, and their extensive repetition of poetic formulae. In each case I discuss the deployment and significance of these poetic elements within the collection and consider the intertextual parallels suggested by their recurrence in Greek literary texts of all periods. This analysis reveals the hymns’ engagement with an overlapping set of poetic traditions, including, most prominently, cultic hymns and oracles, gnomic poetry, the theological discourses of the Presocratic philosophers and, in particular, Orphic poetry in its many forms. It suggests moreover that the hymns engage deeply with the oral strategies of the earliest Greek poets, underscoring the conclusion reached by several recent scholars, that the extant collection is essentially performative and was intended to be recited and heard. I argue that the Orphic Hymns were not a unique text in their employment of the stylistic features studied here, but drew extensively upon earlier hymns composed in Orpheus’ name. I further consider, in the light of this argument, the bearing this study has on the unresolved questions of the hymns’ composition, whether by a single author or many, and the aims of the poet(s) who composed them. , Thesis (PhD) -- Faculty of Humanities, School of Languages and Literature Studies, 2022
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Date Issued: 2022-10-14

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A critical analysis of the tax treatment of cryptocurrencies in a South African context

- Ho, Dau-Ming

Authors: Ho, Dau-Ming
Date: 2022-10-14
Subjects: Cryptocurrencies Taxation , Income tax Law and legislation South Africa , Income tax Law and legislation Australia , Financial services industry Security measures , South Africa. Income Tax Act, 1962
Language: English
Type: Academic theses , Master's theses , text
Identifier: http://hdl.handle.net/10962/357504 , vital:64749
Description: The aim of the present research was to investigate whether, as claimed by the South African Revenue Service in the media release issued in April 2018, the normal income tax provisions could apply to cryptocurrency transactions. To achieve this aim, a literature review was undertaken to describe the nature of cryptocurrencies and related crypto mining activities, providing definitions of cryptocurrencies, blockchains and crypto mining, as well as describing the functioning of the system. The research then proceeded to analyse the provisions of the definition of “gross income” in section 1 of the Income Tax Act, 58 of 1962, as amended, and the requirements of the “general deduction formula” in terms of the preamble to section 11, section 11(a) and section 23(g), as applying to cryptocurrency transactions. The application of other provisions in the Act to cryptocurrency transactions was analysed, including trading stock in terms of section 22, and capital allowances in terms of sections 11(e), 12C and 13quin of the Act, together with capital gains tax consequences in terms of the Eighth Schedule to the Income Tax Act. The regulation for income tax purposes of cryptocurrency transactions in Australia was discussed, with a view to making similar recommendations in South Africa. The research was situated in the interpretative paradigm, a doctrinal methodology was applied, together with a qualitative analysis of documentary data. The discussion was limited to the income tax consequences of cryptocurrencies as applying to individuals. The findings of the research were that, in general, the normal income tax provisions could apply to cryptocurrency transactions, but based on the analysis of the South African and Australian income tax acts as they apply to cryptocurrencies, it was recommended that a Comprehensive Guide on the income tax consequences of cryptocurrency transactions should be issued by the South African Revenue Service, together with amendments to section 25D and paragraph 43 of the Eighth Schedule to the Income Tax Act to deal with the conversion of cryptocurrencies to Rand values, and to section 9C of the Income Tax Act to include the deemed capital nature of the disposal of cryptocurrencies in the three-year rule presently applying to equity shares. , Thesis (MCom) -- Faculty of Commerce, Accounting, 2022
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Date Issued: 2022-10-14

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A critical analysis of the Urban Food System, Urban Governance and Household Food Security in Bulawayo, Zimbabwe

- Maphosa, Mandlenkosi

Authors: Maphosa, Mandlenkosi
Date: 2022-10-14
Subjects: Food security Zimbabwe Bulawayo , City planning Government policy Zimbabwe Bulawayo , Urban poor Zimbabwe Bulawayo , Urban agriculture Zimbabwe Bulawayo , COVID-19 (Disease) Zimbabwe Bulawayo , Agent (Philosophy)
Language: English
Type: Academic theses , Doctoral theses , text
Identifier: http://hdl.handle.net/10962/327165 , vital:61087 , DOI 10.21504/10962/327165
Description: Urbanisation is occurring on a massive scale globally and even more so in the less developed regions of the Global South including sub-Saharan Africa (SSA). Like other developing regions of the world, urbanisation in SSA is not occurring alongside a corresponding growth in urban economies. Resultantly, it is taking place in tandem with the rising scourge of urban poverty, including food insecurity. While urban food insecurity is a clear challenge in SSA, the challenge has however not been met with equal vigour in policy making and implementation circles and even in academia. Problematically, the urban food security literature often focuses on one element of the food system without giving due attention to other components of the system. Resultantly, broader systemic failures and the dynamics related to the different actors across the system-elements are missed. There has thus been recent calls to embrace urban governance in studying urban food systems, which this study does. The thesis examines the urban food system in Bulawayo (in Zimbabwe) with specific reference to urban governance and household food security to understand sociologically the complex multi-dimensional processes, structures, systems, and practices underpinning the urban food system. As a result of the complex nature of food systems, an eclectic analytical framework is employed encompassing Obeng Odoom’s DED framework, Clapp and Fuchs’ framework of power, Gaventa’s power cube and theories of everyday life derived from de Certeau and Lefebvre. Methodologically, the study is informed by a Critical Realism paradigm which accommodates the convergent mixed methods research design employed. The research strategy employed was that of a survey and case study. Key findings reveal that the Bulawayo food system, from production to consumption, is complex and is nested within broader national and international food systems. Although without a direct and explicit mandate on food security, the local authority is at the centre of urban governance processes as it employs a plethora of strategies to influence the nature of the food system. However, the study reveals that the food system is as much a construction from below through the agential activities of the urban poor. , Thesis (PhD) -- Faculty of Humanities, Sociology, 2022
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Date Issued: 2022-10-14

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A review of the Siyakhula Living Lab’s network solution for Internet in marginalized communities

- Muchatibaya, Hilbert Munashe

Authors: Muchatibaya, Hilbert Munashe
Date: 2022-10-14
Subjects: Information and communication technologies for development , Information technology South Africa , Access network , User experience , Local area networks (Computer networks) South Africa
Language: English
Type: Academic theses , Master's theses , text
Identifier: http://hdl.handle.net/10962/364943 , vital:65664
Description: Changes within Information and Communication Technology (ICT) over the past decade required a review of the network layer component deployed in the Siyakhula Living Lab (SLL), a long-term joint venture between the Telkom Centres of Excellence hosted at University of Fort Hare and Rhodes University in South Africa. The SLL overall solution for the sustainable internet in poor communities consists of three main components – the computing infrastructure layer, the network layer, and the e-services layer. At the core of the network layer is the concept of BI, a high-speed local area network realized through easy-to deploy wireless technologies that establish point-to-multipoint connections among schools within a limited geographical area. Schools within the broadband island become then Digital Access Nodes (DANs), with computing infrastructure that provides access to the network. The review, reported in this thesis, aimed at determining whether the model for the network layer was still able to meet the needs of marginalized communities in South Africa, given the recent changes in ICT. The research work used the living lab methodology – a grassroots, user-driven approach that emphasizes co-creation between the beneficiaries and external entities (researchers, industry partners and the government) - to do viability tests on the solution for the network component. The viability tests included lab and field experiments, to produce the qualitative and quantitative data needed to propose an updated blueprint. The results of the review found that the network topology used in the SLL’s network, the BI, is still viable, while WiMAX is now outdated. Also, the in-network web cache, Squid, is no longer effective, given the switch to HTTPS and the pervasive presence of advertising. The solution to the first issue is outdoor Wi-Fi, a proven solution easily deployable in grass-roots fashion. The second issue can be mitigated by leveraging Squid’s ‘bumping’ and splicing features; deploying a browser extension to make picture download optional; and using Pihole, a DNS sinkhole. Hopefully, the revised solution could become a component of South African Government’s broadband plan, “SA Connect”. , Thesis (MSc) -- Faculty of Science, Computer Science, 2022
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Date Issued: 2022-10-14

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A sociological analysis of the experiences of Zimbabwean teachers in South Africa: the case of KwaZulu-Natal townships and township secondary schools

- Daki, Andile Lebohang

Authors: Daki, Andile Lebohang
Date: 2022-10-14
Subjects: Xenophobia South Africa KwaZulu-Natal , Teachers, Foreign South Africa KwaZulu-Natal , Zimbabweans South Africa KwaZulu-Natal , Teachers, Foreign Social conditions , Marginality, Social , Culture conflict South Africa KwaZulu-Natal
Language: English
Type: Academic theses , Doctoral theses , text
Identifier: http://hdl.handle.net/10962/365953 , vital:65805 , DOI https://doi.org/10.21504/10962/365953
Description: This thesis seeks to understand the social and cultural experiences of Zimbabwean teachers, as foreigners, in KwaZulu-Natal townships, and KwaZulu-Natal township secondary schools, in South Africa. It examines the ways in which Zimbabwean teachers negotiate the social, cultural, and institutional milieu of KwaZulu-Natal townships and secondary schools. In doing so, the thesis draws upon social interface theory, as this theory facilitates an examination and understanding of the ways in which the Zimbabwean teachers interpret the spaces (and lifeworld) of South Africans and, simultaneously, navigate their way in and through these spaces along social and cultural interfaces. While the focus is on the perspectives and practices of the Zimbabwean teachers, the thesis recognises and shows that their socio-cultural experiences are constituted and configured in significant ways by their daily encounters with South Africans. The fieldwork for the thesis involved primarily in-depth interviews with thirty Zimbabwean teachers residing in six selected KwaZulu-Natal townships (and teaching at six different secondary schools), as well as fifteen South African teachers, five school administrators and thirty other South African citizens. The sample of Zimbabwean teachers was stratified in relation to the different townships, as well as gender and the number of years teaching in South Africa, so as to investigate whether and how these variables may configure the socio-cultural experiences of these teachers. A consideration of variation in the number of years of teaching in South Africa in particular allowed for an examination of possible shifts in socio-cultural experiences over time, as negotiation along interfaces is an ongoing and contingent process. The findings demonstrate a range of experiences and challenges faced by Zimbabwean teachers in KwaZulu-Natal (with regard to both township and school life), some of which they share with South African teachers but many of which are unique to them. At the same time, there are important differences amongst Zimbabwean teachers in relation to how they interface with South African citizens and teachers. While some teachers negotiate local spaces through active socialising and assimilating into the lifeworld (township life of South Africans and the institutional culture of township schools), other teachers move through the space by way of isolation, withdrawal, and alienation. In general, in terms of adjusting to the lifeworld of South Africans in KwaZulu-Natal townships and schools, Zimbabwean teachers pursue different routes which, in the end, made sense to them and about which they express some degree of personal comfort. , Lo mbhalo wobuhlakani uzama ukuqonda inhlalo kanye namasiko abahlangabezana nako othisha baseZimbabwe njengabantu bokufika emalokishini akwaZulu-Natal, kanye nasezikoleni zamabanga athe thuthu zasemalokishini akwaZulu-Natal eNingizimu-Afrika. Uhlolisisa izindlela labo thisha ababonisana ngazo ngamasiko kanye nenhlalakahle yasezikoleni zasemalokishini akwaZulu-Natal. Ngokwenzanjalo, lo mbhalo udonsa umhlahlandlela wenhlalakahle nokuhlangana ngoba ukungena kwabo endaweni yakwaZulu-Natal, labo thisha bahumusha indawo baphinde babonisane bachushisane ngenqubekela phambili yabo nangenhlalo namasiko abahlangabezana nawo. Ukuhlanganisa othisha baseNingizimu-Afrika nezakhamuzi kumele kusebenzisane ngokulingana. Abahlangabezana nakho kwakhiwa ngokubambisana phakathi kwabaseZimbabwe kanye nabaseNingizimu-Afrika ukuze izwi labaseNingizimu-Afrika lingagqibeki ngoba sekunakekelwa kakhulu abseZimbabwe. Umsebenzi wasensimini walo mbhalo wobuhlakani uhlanganisa ucwaningo kothisha abangani-30 baseZimbabwe abahlala ezindaweni ezingu-6 ezikhethekile ezisemalokishini akwaZulu-Natal, nothisha abayi-15 baseNingizimu-Afrika kanye nabaphathi bezikole abayi-5. Kubuye kwenziwa ucwaningo kwizakhamuzi ezingama-30 zaseNingizimu-Afrika. Isampula lihlanganiswe ngokubuka indawo lapho aphuma khona umuntu, kanye neminyaka aseyifundisile eNingizimu-Afrika. Ucwaningo lubukisise kakhulu indlela ababuka ngayo inhlalakahle namasiko kube kubukisiswa nenani leminyaka aseyifundisile umuntu ngamunye ukuze kuhlolisiswe izinguquko zokuxoxisana ezidalwe yisikhathi asihlalile umuntu phakathi kothisha abasebancane nalabo asebekhulile. Imiphumela yocwaningo iveza iznselele ezahlukene ababhekene nazo othisha baseZimbabwe njengoba bengabahlali baseNingizimu-Afrika. Ezinye zalezi nselele ziqhamuka ngokwehlukana kwemiphakathi kwabaseZimbabwe kanye nabaseNingizimu-Afrika. Ngokunjalo kunomehluko obalulekayo kothisha baseZimbabwe mayelana nendlela ukuxoxisana nokubonisana okuqhubeka ngayo. Kukhona labo ukungena bathi khaxa emiphakathini nasezimpilweni abakuzo eNingizimu-Afrika nasezikoleni abakuzo namasiko nenhlalakahle yakulezo zindawo ngakolunye uhlangothi abanye othisha bazithole bephila njengenhlwa bephila ngabodwana eNingizimu-Afrika. Kodwa ekugcineni kwakho konke, lolu cwaningo luthola ukuthi othisha baseZimbabwe ezikoleni zasemalokishini akwaZulu-Natal lapha eNingizimu-Afrika bazakhela impilo eyenza umuntu ngamunye azizwe ehlaliseke kahle eNingizimu- Afrika ngendlela ephelele nethokomalisa yena ngo kwakhe. , Thesis (PhD) -- Faculty of Humanities, Sociology, 2022
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Date Issued: 2022-10-14

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A systematic methodology to evaluating optimised machine learning based network intrusion detection systems

- Chindove, Hatitye Ethridge

Authors: Chindove, Hatitye Ethridge
Date: 2022-10-14
Subjects: Intrusion detection systems (Computer security) , Machine learning , Computer networks Security measures , Principal components analysis
Language: English
Type: Academic theses , Master's theses , text
Identifier: http://hdl.handle.net/10962/362774 , vital:65361
Description: A network intrusion detection system (NIDS) is essential for mitigating computer network attacks in various scenarios. However, the increasing complexity of computer networks and attacks makes classifying unseen or novel network traffic challenging. Supervised machine learning techniques (ML) used in a NIDS can be affected by different scenarios. Thus, dataset recency, size, and applicability are essential factors when selecting and tuning a machine learning classifier. This thesis explores developing and optimising several supervised ML algorithms with relatively new datasets constructed to depict real-world scenarios. The methodology includes empirical analyses of systematic ML-based NIDS for a near real-world network system to improve intrusion detection. The thesis is experimental heavy for model assessment. Data preparation methods are explored, followed by feature engineering techniques. The model evaluation process involves three experiments testing against a validation, un-trained, and retrained set. They compare several traditional machine learning and deep learning classifiers to identify the best NIDS model. Results show that the focus on feature scaling, feature selection methods and ML algo- rithm hyper-parameter tuning per model is an essential optimisation component. Distance based ML algorithm performed much better with quantile transformation whilst the tree based algorithms performed better without scaling. Permutation importance performs as a feature selection method compared to feature extraction using Principal Component Analysis (PCA) when applied against all ML algorithms explored. Random forests, Sup- port Vector Machines and recurrent neural networks consistently achieved the best results with high macro f1-score results of 90% 81% and 73% for the CICIDS 2017 dataset; and 72% 68% and 73% against the CICIDS 2018 dataset. , Thesis (MSc) -- Faculty of Science, Computer Science, 2022
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Date Issued: 2022-10-14

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An analysis of inland fisheries resource use in the Eastern Cape, South Africa

- Matam, Ncumisa Yanga

Authors: Matam, Ncumisa Yanga
Date: 2022-10-14
Subjects: Fisheries South Africa Eastern Cape , Fishery law and legislation South Africa Eastern Cape , Small-scale fisheries South Africa Eastern Cape , Small-scale fisheries Social aspects South Africa Eastern Cape , Small-scale fisheries Economic aspects South Africa Eastern Cape , SADC Inland Fisheries Sector , Subsistence fishing South Africa Eastern Cape , Draft Inland Fisheries Policy (South Africa)‎
Language: English
Type: Master's thesis , text
Identifier: http://hdl.handle.net/10962/232215 , vital:49972
Description: South Africa’s Draft Inland Fisheries Policy identifies inland fisheries as an opportunity for socio-economic benefits such as jobs, food security and economic development, based on small-scale fishing and recreational value chains. Using roving creel surveys, this study examined various fishing groups in publicly accessible dams in both an urban and a rural settlement in the Makana Municipal area, Eastern Cape, South Africa. While inland fisheries are particularly relevant for rural communities, there is very little information on the current use of these resources, irrespective of inland fisheries’ importance. This thesis presents a conceptual framework for a study that: (1) reviews available information of inland fisheries and development attempts in South Africa; (2) provides an assessment of the use of inland fisheries on publicly accessible dams in the Makana Municipal area and (3) evaluates case studies of current and past utilization of selected inland fisheries initiatives in the Eastern Cape. The results of this project provide insights into the current conditions and development potentials of inland fisheries in the Eastern Cape. There was a difference in species composition between the dams, but no difference in the CPUE between dams. For example, in Grey dam many species were present, but as the dam size is only one hectare, this would result in an estimated yield harvest of only 207 kg/ha/year. Anglers were encountered at all dams, although fish were only retrieved by anglers in the rural dams of Committees Drift. Dam usage in the rural area was mostly subsistence angling, and this was significantly greater than in the urban area. Subsistence fishers utilised the fish to sustain themselves and their families and for better livelihoods. Anglers from outside the area tended to utilise the dam for recreational angling. Dams found in the urban area were also mostly used by subsistence anglers, though there were a few uses for aesthetic purposes. The urban dams were also utilised recreationally (picnics, year-end functions, swimming), as opposed to the rural dams which were only used for angling. A total of 10 interviews were administered to key respondents in the form of a questionnaires to determine the importance of the fisheries to them. Catch documented from the questionnaires, interviews and logbooks constituted 1238 species and 978 020 kg. Of all the anglers encountered from the interviews, the gill net catch species varied by dam. The fate of fish caught by anglers was dependent on employment status, with most unemployed anglers selling their fish for income and most employed anglers consuming their catch. The findings show that dams were used mostly by small-scale fishers and recreational anglers. Ichthyological surveys revealed that popular fish harvested were moggel, common carp, largemouth bass and Mozambique tilapia. The results are discussed in the context of appropriate development of fisheries in small dams in the province, with recommendations to continue monitored surveys to better inform the inland fisheries policy. The findings from this thesis show that having small scale fisheries in place and providing good access to the dams is essential for rural populations, in turn, providing better livelihoods through hunger alleviation and generating household income. , Thesis (MSc) -- Faculty of Science, Environmental Science, 2022
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Date Issued: 2022-10-14

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An in-silico study of the type II NADH: Quinone Oxidoreductase (ndh2). A new anti-malaria drug target

- Baye, Bertha Cinthia

Authors: Baye, Bertha Cinthia
Date: 2022-10-14
Subjects: Malaria , Plasmodium , Molecular dynamics , Computer simulation , Quinone , Antimalarials , Molecules Models , Docking , Drugs Computer-aided design
Language: English
Type: Academic theses , Doctoral theses , text
Identifier: http://hdl.handle.net/10962/365633 , vital:65767 , DOI https://doi.org/10.21504/10962/365633
Description: Malaria is caused by Plasmodium parasites, spread to people through the bites of infected female Anopheles mosquitoes. This study focuses on all 5 (Plasmodium falciparum, Plasmodium knowlesi, Plasmodium malariae, Plasmodium ovale and Plasmodium vivax) parasites that cause malaria in humans. Africa is a developing continent, and it is the most affected with an estimation of 90% of more than 400 000 malaria-related deaths reported by the World Health Organization (WHO) report in 2020, in which 61% of that number are children under the ages of five. Malaria resistance was initially observed in early 1986 and with the progression of time anti-malarial drug resistance has only increased. As a result, there is a need to study the malarial proteins mechanism of action and identify alternative treatment strategies for this disease. Type II NADH: quinone oxidoreductase (NDH2) is a monotopic protein that catalyses the electron transfer from NADH to quinone via FAD without a proton-pumping activity, and functions as an initial enzyme, either in addition to or as an alternative to proton-pumping NADH dehydrogenase (complex I) in the respiratory chain of bacteria, archaea, and fungal and plant mitochondrial. The structures for the Plasmodium knowlesi, Plasmodium malariae, Plasmodium ovale and Plasmodium vivax were modelled from the crystal structure of Plasmodium falciparum (5JWA). Compounds from the South African natural compounds database (SANCDB) were docked against both the NDH2 crystal structure and modelled structures. By performing in silico screening the study aimed to find potential compounds that might interrupt the electron transfer to quinone therefore disturbing the enzyme‟s function and thereby possibly eliminating the plasmodium parasite. CHARMM-GUI was used to create the membrane (since this work is with membrane-bound proteins) and to orient the protein on the membrane using OPM server guidelines, the interface produced GROMACS topology files that were used in molecular dynamics simulations. Molecular dynamics simulations were performed in the Centre for high performance computing (CHPC) cluster under the CHEM0802 project and the trajectories produced were further analysed. In this work not only were hit compounds from SANCDB identified, but also differences in behaviour across species and in the presence or absence of the membrane were described. This highlights the need to include the correct protein environment when studying these systems. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2022
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Date Issued: 2022-10-14

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An investigation into water and sanitation in the Eastern Cape Province and potential for implementation of biotechnology platforms

- Gumunyu, Wilbert

Authors: Gumunyu, Wilbert
Date: 2022-10-14
Subjects: Sewage South Africa Eastern Cape , Sanitation South Africa Eastern Cape , Algae Biotechnology , Biotechnology , Sewage Purification Biological treatment , Algal biofuels
Language: English
Type: Academic theses , Master's theses , text
Identifier: http://hdl.handle.net/10962/362830 , vital:65366
Description: In contemporary South Africa, a country in transition, destruction rather than reconstruction seems commonplace. Electricity supply is at an all-time low and ‘load shedding’ is an almost daily occurrence. Similarly, more fragility of water delivery and sanitation service is being reported with the likelihood of ‘water shedding’ a soon-to-be reality. In view of the ever-increasing reported mismanagement of South Africa’s water and sanitation infrastructure, which is likely nearing the point of collapse if not already collapsed, this thesis set out to interrogate at a provincial and municipal level the status of water and sanitation in Chris Hani District Municipality (CHDM), Eastern Cape Province. One major driver behind this study was to evaluate provincial and municipal water/wastewater infrastructure as a platform to support implementation of locally developed bioprocess technologies. First, publicly available historical data was used to derive a baseline or benchmark from which to determine gains/losses in compliance, water quality and efficiency. The period 2009-2013/4 during which Blue and Green Drop reporting was routine, was used as an appropriate start point. Data thus derived indicated that, at provincial and district municipality (DM) level, potable water supply was by bulk water schemes and, sanitation was typically by waste stabilization pond (WSP) treatment of municipal sewage. The derived benchmark for the period 2009-2013/14 indicated that most plants were not compliant (~75% of the Eastern Cape Province water treatment plants (WTP) operating between average performance to critical state), operated either at- or above design capacity (Eastern Cape Province, 16%; CHDM, 19%). A large number of plants for the province (62.4%) and district (81.25%) had hydraulic design capacity or average daily flows that were unknown (information not provided in available literature or plant reports) and final effluent did not always meet the general standard (70.3% of the CHDM wastewater treatment works (WWTW)). To determine the contemporary state (2020 - 2022) of water and sanitation within CHDM, a scoping exercise of WTP and WWTW in selected local municipalities was carried out. This was done along a west-east transect by appraising WTP and WWTW in the towns of Cradock, Tarkastad, Komani, Tsomo, Cacadu, and Ngcobo. Furthermore, targeted assessment of the Queenstown WTP and the Cradock WWTW was used to derive real-time data on the status of water and sanitation infrastructure. Results showed that water and sanitation services within CHDM had, in the years between 2009-2013/14 to date, deteriorated. Freshwater demand significantly exceeded capability of water supply schemes, where demand was as much as three times greater than reported available supply. For most WWTW, operation was in excess of capacity and between 1.52 and 12 times installed hydraulic loading. The targeted scoping exercise revealed that Queenstown WTP is a moderate risk plant (Cumulative risk rating, CRR = 11 and maximum risk rating, MRR = 47.8%), whereas Cradock WWTW was in working condition but with challenges and some infrastructural dysfunction. Assessment of water/effluent quality revealed that turbidity and TOC were above SANS 241 general limit. Non-compliance in terms of nitrate/nitrite-N, ammonium-N, phosphate-P, TSS, total coliforms, E. Coli, and free chlorine was evident at Cradock WWTW. Unstructured interviews with plant operators corroborated these findings. The overwhelming support for bulk schemes for potable water provision and WSP for sanitation indicated a partially water secure municipal district but derelict in terms of its sanitation services. The later, it was concluded, in particular provides an ideal opportunity for implementation of platform technologies to support bioprocesses for entrepreneurship, employment, economic benefit and to secure a closed circular economy for regional water and sanitation through valorisation of co-product streams. Among the co-product streams considered in this thesis are biomass, biogas, biofertilizers, biofuels and several high value chemical products. , Thesis (MSc) -- Faculty of Science, Institute for Environmental Biotechnology, 2022
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Date Issued: 2022-10-14

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Assessment of cytotoxic artemisinin and its derivatives as DNA damaging inducing agents in triple-negative breast cancer cells

- Mkhwanazi, Ntando

Authors: Mkhwanazi, Ntando
Date: 2022-10-14
Subjects: Breast Cancer , Artemisinin , DNA damage , Antineoplastic agents , Breast Cancer Treatment
Language: English
Type: Academic theses , Master's theses , text
Identifier: http://hdl.handle.net/10962/362960 , vital:65378
Description: In developing countries, including South Africa, breast cancer is the primary cause of cancer-related deaths among women. TNBC (triple-negative breast cancer) is an aggressive breast cancer subtype that is more prevalent in women of African descent. This subtype lacks the key receptors, namely the estrogen receptor (ER-), progesterone receptor (PR-), and human epidermal growth factor receptor 2 (HER2-) that are the basis of successful targeted therapies for other subtypes of the disease. To date, there are no effective, standardized targeted therapies for TNBC. Artemisinin is an anti-malarial drug and numerous derivatives of the compound have been developed to improve the potency and solubility of the parent compound. Artemisinin and its derivatives have gained attention as potential anti-cancer agents; however, such studies have not yet progressed to clinical trials and the precise mechanism of action of these compounds is yet to be fully explained. In this study, artemisinin, and its known derivative artesunate, as well as a novel derivative, WHN11, were investigated as DNA damage-inducing agents in TNBC. WHN11 was found to be the most potent of the three compounds, displaying an IC50 of 3.20 μM against HCC70 cells, artemisinin displayed an IC50 of 214.70 μM and artesunate displayed an IC50 of 25.48 μM. The compounds were less toxic to the MCF12A non-cancerous cells, with IC50 values 298.30, 87.53, and 8.35 μM for artemisinin, artesunate, and WHN11, respectively, and displayed selectivity indices of 1.39, 3.44 and 2.61 μM for artemisinin, artesunate, and WHN11, respectively. In silico and in vitro studies revealed that the artemisinin compounds bind to DNA through the minor groove. While all three compounds were able to bind to DNA, a comet assay revealed that only artemisinin and artesunate, and not WHN11, were able to cause DNA damage compared to the vehicle control, DMSO. Finally, a topoisomerase I (TOPO I) enzyme assay demonstrated that while the compounds appeared to display a degree of inhibition of TOPO I, as evidenced by a downward shift in the plasmid band on the agarose gel, they were not able to fully inhibit the enzyme to return the plasmid to the supercoiled conformation. In addition, combination studies revealed that artemisinin, artesunate, and WHN11 acted synergistically in combination with camptothecin, but displayed either an additive (artemisinin) or antagonistic (artesunate and WHN11) relationship when used in combination with etoposide. In conclusion, artemisinin, its known derivative artesunate, and novel and highly toxic derivative WHN11, all bind to DNA via the minor groove, however only artemisinin and artesunate, and not WHN11, cause DNA damage, indicating a potentially different mechanism of action of the three artemisinins. All three compounds act synergistically with camptothecin, which suggests interference with topoisomerase activity, partially supported by slight inhibition of TOPO I activity, and could indicate either direct inhibition of the enzyme or interference with enzyme function by competitive binding to the DNA. Further studies could help explore alternate DNA damage assays, to validate these findings, and the effect of the compounds on TOPO II activity could also be assessed. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2022
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Date Issued: 2022-10-14

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Bioinformatics tool and web server development focusing on structural bioinformatics applications

- Nabatanzi, Margaret

Authors: Nabatanzi, Margaret
Date: 2022-10-14
Subjects: Structural bioinformatics , Proteins Structure , Protein structure prediction , Proteins Conformation , Protein complex
Language: English
Type: Academic theses , Doctoral theses , text
Identifier: http://hdl.handle.net/10962/365700 , vital:65777 , DOI https://doi.org/10.21504/10962/365700
Description: This thesis is divided into two main sections: Part 1 describes the design, and evaluation of the accuracy of a new web server – PRotein Interactive MOdeling (PRIMO-Complexes) for modeling protein complexes and biological assemblies. The second part describes the development of bioinformatics tools to predict HIV-1 drug resistance and support bioinformatics research and education. Recent technological advances have resulted in a tremendous increase in the number of sequences and protein structures deposited in the Universal Protein Resource Knowledgebase (UniProtKB) and the Protein Data Bank (PDB). However, the number of sequences has increased at a higher rate compared with the experimentally solved multimeric protein structures. This is partly due to advances in high-throughput sequencing technology. To fill this protein sequence-structure gap, computational approaches have been developed to predict protein structures from available sequences. Computational approaches include template-based and ab initio modeling with the former being the most reliable. Template-based modeling process can be achieved using either standalone software or automated modeling web servers. However, using standalone software requires familiarity with command-line interfaces as well as utilising other intermediate programs which could be daunting to novice users. To alleviate some of these problems, the modeling process has been automated, however, it still has numerous challenges. To date, only a few web servers that support multimeric protein modeling have been developed and even these provide little, if any user involvement in the process. To address some of these issues, a new web server – PRIMO-Complexes – was developed to model protein complexes and biological assemblies. The existing PRIMO web server could only model monomeric proteins. Part 1 of this thesis provides a detailed account of the development and evaluation of PRIMO-Complexes. The rationale for developing this new web server was based on the understanding that most proteins function as protein multimers and often the ligand-binding sites, and enzyme active sites are located at the protein-protein interfaces. It, therefore, necessitated developing capabilities for modeling multimeric proteins. PRIMO-Complexes web server was developed using the Waterfall system development life cycle model, is based on the Django web framework and makes use of high-performance computing resources to execute jobs. The accuracy of the algorithms embedded in PRIMO- Complexes was evaluated and the results were promising. Additionally, PRIMO-Complexes performs comparatively well in relation to other web servers that offer multimeric protein modeling. Another unique feature of PRIMO-Complexes is its interactivity. The webserver was developed with capabilities for allowing users to model multimeric proteins with an appreciable degree of control over the process. In the second part of the thesis several other bioinformatics tools are described, for example, a webserver for predicting HIV-1 drug resistance, the RUBi protein model repository, and a bioinformatics web portal for education and research resources. RUBi protein model repository stores verified theoretical models built using various modeling approaches. This enables users to easily access models to reproduce and/or further the research. This is described in chapter 5. Chapter 6 describes the design and development of the Human Immunodeficiency type 1 Resistance Predictor (HIV-1 ResPredictor), a web application that employs artificial neural networks (ANN) to predict drug resistance in patients infected with HIV-1 subtype B. The ANNs and subtype classifiers performed well making this web application potentially useful to both clinicians and researchers in this era of personalised medicine. Finally, chapter 7 describes a bioinformatics education web portal that equips students with information on how to use bioinformatics online resources. Being aware of these resources is not enough without a deeper understanding and guidance on how to apply bioinformatics methods to solve practical problems. This web portal was aimed at familiarising students with the basic terminology and approaches in structural bioinformatics. Students will potentially gain skills to conduct real-life bioinformatics research to obtain biological insights. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2022
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Date Issued: 2022-10-14

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