Photodynamic anticancer and antimicrobial activities of aza-BODIPY and porphyrinbased photosensitisers and their non-linear properties
- Authors: Molupe, Nthabeleng Regina
- Date: 2024-10-11
- Subjects: Photochemotherapy , Anti-infective agents , Nonlinear optics , Cancer Treatment , BODIPY , Porphyrins
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466603 , vital:76758 , DOI https://doi.org/10.21504/10962/466603
- Description: New aza-BODIPY dyes and porphyrins were synthesised and characterised so that photodynamic therapy (PDT) and photodynamic antimicrobial chemotherapy (PACT) activity studies could be performed. Several strategies were explored to achieve targeted nanoplatforms or biocompatible nanoplatforms to enhance the suitability of these compounds for use in PDT. Following earlier MSc research on the encapsulation of halogenated boron dipyrromethene (BODIPY) dyes into Pluronic® micelles, similar nanomicelles were prepared to encapsulate halogenated boron aza-dipyrromethene (aza-BODPY) dyes to enhance their aqueous solubility. However, the 1,7-dimethylthiophenyl- 2,6-diiodo-3,5-diphenyl (1) and 1,7-di-methylthiophenyl-2,6-diiodo- 3,5-dithien-3-yl (2) aza-BODIPY dyes that were prepared in this context were found to degrade when encapsulated. A different strategy was then followed in which gold nanoparticles (AuNPs) were conjugated to 1 and 2 via Au-S interactions to form biocompatible aza-BODIPY-AuNP conjugates (1-AuNP and 2-AuNP). This strategy was successful, and favourable IC50 values of 3.60 and 10.0 μM for 1-AuNP and 2- AuNP were obtained during in vitro PDT activity studies against MCF-7 human breast cancer cells, respectively, while values of 11.0 and 12.8 μM were obtained for 1 and 2. To further explore the preparation of better-targeted aza-BODIPY photosensitiser dyes, folic acid (FA) was conjugated to 1,7-dihydroxyphenyl-2,6-diiodo-3,5-di-4- bromophenyl (3) and 1,7-di-4-bromo-2,6-diiodo-3,5-dihydroxyphenylphenyl (4) aza- BODIPYs via ester bonds. Not only was the conjugation to form 3-FA and 4-FA successful, but the conjugated dyes are water-soluble, which is advantageous for drug transport in the context of PDT. These conjugates were applied in vitro against MCF-7 cancer cells and were found to have relatively high activities with IC50 values of 0.91 and 7.48 μM for 3-FA and 4-FA, respectively, while values of 11.3 and 13.0 μM were obtained for the non-conjugated 3 and 4 dyes. In a similar manner, tin (IV) and indium (III) tetrapyridylporphyrins (5 and 6) were axially conjugated to folic acid via ester bonds (5-FA and 6-FA). The conjugation was successful and enhanced the PDT activities of the dyes MCF-7 cancer cells in vitro from 48.2 to 29.6 μM for 5 and 5-FA, and from 43.9 to 13.3 μM for 6 and 6-FA. Relatively high dark toxicity was observed for 6-FA of 26.1 μM. When the nitrogen atoms of the meso-pyridyl rings were quaternized (5-FAQ and 6-FAQ) to further enhance the aqueous solubility of the complexes, it was not possible to calculate an IC50 value. When octanol-water partition coefficients (Log P) were calculated by the shake flask method, values of −0.70 and −1.70 were obtained for 5-FAQ and 6-FAQ, respectively. This provides evidence that the dyes are too water-soluble and not sufficiently lipophilic. The PACT activity properties of the synthesised diiodinated aza-BODIPYs were studied against Staphylococcus aureus (S. aureus) through photoirradiation for 60 min with Thorlabs M660L4 (280 mW.cm−2) and M730L4 (160 mW.cm−2) light emitting diodes (LEDs) mounted on the illumination chamber of Modulight® 7710-680 medical laser system providing doses at the well-plate of 100 and 57 J.cm−2.min−1. Aza- BODIPYs 2, 3 and 4 all inhibited the growth of S. aureus but with relatively low Log10 reductions of 1.37, 1.20 and 0.20. In contrast, aza-BODIPY 1 was found to have a Log10 reduction of 7.82. The PACT activities of free base and Sn(IV) 5-[4-(3- bromoethylcarboxyamidyl)phenyl]-10,15,20-triphenylporphyrins (7 and 8) prepared by Dr Balaji Babu (New Journal of Chemistry 2022, 46, 5288-5295) were tested against S. aureus to determine whether adding a triphenylphosphonium moiety to form free base and Sn(IV) 5-[4-(triphenylphosphonium)ethylcarboxyamidyl)phenyl]-10,15,20- triphenylporphyrin (18 and 19) enhances the photo-induced antibacterial activity, in addition to optimising the PDT properties due to its mitochondria-targeting properties. The PACT activities obtained against S. aureus were not favourable, but 18 exhibited enhanced activity across the studied concentration range. The potential utility of aza-BODIPY dyes 1-4 and their non-iodinated analogues (1a- 4a) for optical limiting applications was analysed by carrying out a series of Z-scan measurements, since dyes of this type have large ground state dipole moments, and this can enhance the non-linear optical limiting response. All the aza-BODIPY dyes under investigation exhibited intense non-linear absorption (NLA) behaviour with Zscan profiles that contain significant reverse saturable absorption (RSA) responses. Aza-BODIPYs 1, 2a, 2, 3, 4a, and 4 decreased the transmitted intensity of the strong laser beam to less than 50% of the linear response in organic solutions with a fixed absorbance of 1.8 for the main aza-BODIPY spectral band and a laser pulse input energy of 42 μJ. Higher second-order hyperpolarizability (γ) values were obtained for iodinated dyes 1, 2, 3 and 4. The highest value of 3.15×10−29 esu was obtained for 1. A comparative study involving the four non-iodinated dyes 1, 2, 3 and 4 and seven 1,3,5,7-tetraaryl aza-BODIPY dyes reported previously in the PhD thesis of Gugu Kubheka at Rhodes University demonstrated that there was no clear trend correlation between the γ values calculated from the Z-scan measurements and calculated dipole moments. , Thesis (PhD) -- Faculty of Science, Chemistry, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Molupe, Nthabeleng Regina
- Date: 2024-10-11
- Subjects: Photochemotherapy , Anti-infective agents , Nonlinear optics , Cancer Treatment , BODIPY , Porphyrins
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466603 , vital:76758 , DOI https://doi.org/10.21504/10962/466603
- Description: New aza-BODIPY dyes and porphyrins were synthesised and characterised so that photodynamic therapy (PDT) and photodynamic antimicrobial chemotherapy (PACT) activity studies could be performed. Several strategies were explored to achieve targeted nanoplatforms or biocompatible nanoplatforms to enhance the suitability of these compounds for use in PDT. Following earlier MSc research on the encapsulation of halogenated boron dipyrromethene (BODIPY) dyes into Pluronic® micelles, similar nanomicelles were prepared to encapsulate halogenated boron aza-dipyrromethene (aza-BODPY) dyes to enhance their aqueous solubility. However, the 1,7-dimethylthiophenyl- 2,6-diiodo-3,5-diphenyl (1) and 1,7-di-methylthiophenyl-2,6-diiodo- 3,5-dithien-3-yl (2) aza-BODIPY dyes that were prepared in this context were found to degrade when encapsulated. A different strategy was then followed in which gold nanoparticles (AuNPs) were conjugated to 1 and 2 via Au-S interactions to form biocompatible aza-BODIPY-AuNP conjugates (1-AuNP and 2-AuNP). This strategy was successful, and favourable IC50 values of 3.60 and 10.0 μM for 1-AuNP and 2- AuNP were obtained during in vitro PDT activity studies against MCF-7 human breast cancer cells, respectively, while values of 11.0 and 12.8 μM were obtained for 1 and 2. To further explore the preparation of better-targeted aza-BODIPY photosensitiser dyes, folic acid (FA) was conjugated to 1,7-dihydroxyphenyl-2,6-diiodo-3,5-di-4- bromophenyl (3) and 1,7-di-4-bromo-2,6-diiodo-3,5-dihydroxyphenylphenyl (4) aza- BODIPYs via ester bonds. Not only was the conjugation to form 3-FA and 4-FA successful, but the conjugated dyes are water-soluble, which is advantageous for drug transport in the context of PDT. These conjugates were applied in vitro against MCF-7 cancer cells and were found to have relatively high activities with IC50 values of 0.91 and 7.48 μM for 3-FA and 4-FA, respectively, while values of 11.3 and 13.0 μM were obtained for the non-conjugated 3 and 4 dyes. In a similar manner, tin (IV) and indium (III) tetrapyridylporphyrins (5 and 6) were axially conjugated to folic acid via ester bonds (5-FA and 6-FA). The conjugation was successful and enhanced the PDT activities of the dyes MCF-7 cancer cells in vitro from 48.2 to 29.6 μM for 5 and 5-FA, and from 43.9 to 13.3 μM for 6 and 6-FA. Relatively high dark toxicity was observed for 6-FA of 26.1 μM. When the nitrogen atoms of the meso-pyridyl rings were quaternized (5-FAQ and 6-FAQ) to further enhance the aqueous solubility of the complexes, it was not possible to calculate an IC50 value. When octanol-water partition coefficients (Log P) were calculated by the shake flask method, values of −0.70 and −1.70 were obtained for 5-FAQ and 6-FAQ, respectively. This provides evidence that the dyes are too water-soluble and not sufficiently lipophilic. The PACT activity properties of the synthesised diiodinated aza-BODIPYs were studied against Staphylococcus aureus (S. aureus) through photoirradiation for 60 min with Thorlabs M660L4 (280 mW.cm−2) and M730L4 (160 mW.cm−2) light emitting diodes (LEDs) mounted on the illumination chamber of Modulight® 7710-680 medical laser system providing doses at the well-plate of 100 and 57 J.cm−2.min−1. Aza- BODIPYs 2, 3 and 4 all inhibited the growth of S. aureus but with relatively low Log10 reductions of 1.37, 1.20 and 0.20. In contrast, aza-BODIPY 1 was found to have a Log10 reduction of 7.82. The PACT activities of free base and Sn(IV) 5-[4-(3- bromoethylcarboxyamidyl)phenyl]-10,15,20-triphenylporphyrins (7 and 8) prepared by Dr Balaji Babu (New Journal of Chemistry 2022, 46, 5288-5295) were tested against S. aureus to determine whether adding a triphenylphosphonium moiety to form free base and Sn(IV) 5-[4-(triphenylphosphonium)ethylcarboxyamidyl)phenyl]-10,15,20- triphenylporphyrin (18 and 19) enhances the photo-induced antibacterial activity, in addition to optimising the PDT properties due to its mitochondria-targeting properties. The PACT activities obtained against S. aureus were not favourable, but 18 exhibited enhanced activity across the studied concentration range. The potential utility of aza-BODIPY dyes 1-4 and their non-iodinated analogues (1a- 4a) for optical limiting applications was analysed by carrying out a series of Z-scan measurements, since dyes of this type have large ground state dipole moments, and this can enhance the non-linear optical limiting response. All the aza-BODIPY dyes under investigation exhibited intense non-linear absorption (NLA) behaviour with Zscan profiles that contain significant reverse saturable absorption (RSA) responses. Aza-BODIPYs 1, 2a, 2, 3, 4a, and 4 decreased the transmitted intensity of the strong laser beam to less than 50% of the linear response in organic solutions with a fixed absorbance of 1.8 for the main aza-BODIPY spectral band and a laser pulse input energy of 42 μJ. Higher second-order hyperpolarizability (γ) values were obtained for iodinated dyes 1, 2, 3 and 4. The highest value of 3.15×10−29 esu was obtained for 1. A comparative study involving the four non-iodinated dyes 1, 2, 3 and 4 and seven 1,3,5,7-tetraaryl aza-BODIPY dyes reported previously in the PhD thesis of Gugu Kubheka at Rhodes University demonstrated that there was no clear trend correlation between the γ values calculated from the Z-scan measurements and calculated dipole moments. , Thesis (PhD) -- Faculty of Science, Chemistry, 2024
- Full Text:
- Date Issued: 2024-10-11
Photodynamic anticancer and antimicrobial activities of novel bacteriochlorins
- Tauyakhale, Kaisano Goodness
- Authors: Tauyakhale, Kaisano Goodness
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464587 , vital:76524
- Description: The World Health Organization cautioned that the major contributing factors of cancer amongst people are the excessive usage of alcohol, smoking, lack of exercise and low intake of fruits, vegetables, and high-fibre foods. Furthermore, cancer by far is reported to be the most common and leading cause of death worldwide (1 in 6 deaths is due to cancer). Moreover, it is reported that cancer kills more people than tuberculosis, malaria and AIDS combined every year. Chemotherapy has been utilised as a mode of rehabilitation for complete being used in conjunction with surgery or to improve the state of well-being of patients until their point of death. However, it is well known for its adverse effects, such as loss of hair, altered gastric metabolism, vomiting and nausea, dehydration, weight loss, and loss of appetite. For this reason, photodynamic therapy (PDT) was developed as an alternative. A molecular dye (photosensitiser/PS) and light of a specific wavelength produce cytotoxic singlet oxygen species, which induce cell death. The aim of this project is to prepare novel structurally modified porphyrin-type dyes that absorb far into the near-infrared region. Identifying suitable dyes that absorb significantly in the 700−800 nm region is particularly important from an African perspective, since melanin significantly limits the penetration of laser light into human tissue in the 600−700 nm region, where first- and second-generation photosensitiser dyes usually absorb. The porphyrin analogues that will be investigated in this regard are bacteriochlorins (BChls), which are known to have suitable optical properties that are potentially suitable in this regard. The first step of the study would be to synthesise tetraarylporphyrins with electron- withdrawing meso-aryl rings because their reduction to BChls is more readily attainable than is the case with electron-donating rings. However, these contrasting properties can be combined to tailor the BChls for effective photodynamic therapy, so the type of porphyrins synthesised will be tetraarylBChls with different meso-aryl groups to first analyze the induction of different chemical properties in this case, the impact of introducing electron donating (4- and 3-quinoline substituents) or electron-withdrawing (pentafluorophenyl substituents) groups on the meso-positions of the dyes and more specifically whether the position of the quinoline nitrogen atom relative to the core of the BChl has any significant impact on the reactivity of the dye (the 4- or 3-position of the quinoline). The next factor to be considered is the induction of the heavy atom effect by introducing a metal in the centre of the dye in order to try to increase the singlet oxygen quantum yields for high production of reactive oxygen species and singlet oxygen and further red shift the lowest energy absorption band of the BChls in the therapeutic window for deep tissue penetration for effective. Lastly, the goal will be to explore whether the delivery of bacteriochlorin photosensitisers to cancer cells can be enhanced by introducing quaternised nitrogen atoms to the meso-aryl ligands. , Thesis (MSc) -- Faculty of Science, Chemistry, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Tauyakhale, Kaisano Goodness
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464587 , vital:76524
- Description: The World Health Organization cautioned that the major contributing factors of cancer amongst people are the excessive usage of alcohol, smoking, lack of exercise and low intake of fruits, vegetables, and high-fibre foods. Furthermore, cancer by far is reported to be the most common and leading cause of death worldwide (1 in 6 deaths is due to cancer). Moreover, it is reported that cancer kills more people than tuberculosis, malaria and AIDS combined every year. Chemotherapy has been utilised as a mode of rehabilitation for complete being used in conjunction with surgery or to improve the state of well-being of patients until their point of death. However, it is well known for its adverse effects, such as loss of hair, altered gastric metabolism, vomiting and nausea, dehydration, weight loss, and loss of appetite. For this reason, photodynamic therapy (PDT) was developed as an alternative. A molecular dye (photosensitiser/PS) and light of a specific wavelength produce cytotoxic singlet oxygen species, which induce cell death. The aim of this project is to prepare novel structurally modified porphyrin-type dyes that absorb far into the near-infrared region. Identifying suitable dyes that absorb significantly in the 700−800 nm region is particularly important from an African perspective, since melanin significantly limits the penetration of laser light into human tissue in the 600−700 nm region, where first- and second-generation photosensitiser dyes usually absorb. The porphyrin analogues that will be investigated in this regard are bacteriochlorins (BChls), which are known to have suitable optical properties that are potentially suitable in this regard. The first step of the study would be to synthesise tetraarylporphyrins with electron- withdrawing meso-aryl rings because their reduction to BChls is more readily attainable than is the case with electron-donating rings. However, these contrasting properties can be combined to tailor the BChls for effective photodynamic therapy, so the type of porphyrins synthesised will be tetraarylBChls with different meso-aryl groups to first analyze the induction of different chemical properties in this case, the impact of introducing electron donating (4- and 3-quinoline substituents) or electron-withdrawing (pentafluorophenyl substituents) groups on the meso-positions of the dyes and more specifically whether the position of the quinoline nitrogen atom relative to the core of the BChl has any significant impact on the reactivity of the dye (the 4- or 3-position of the quinoline). The next factor to be considered is the induction of the heavy atom effect by introducing a metal in the centre of the dye in order to try to increase the singlet oxygen quantum yields for high production of reactive oxygen species and singlet oxygen and further red shift the lowest energy absorption band of the BChls in the therapeutic window for deep tissue penetration for effective. Lastly, the goal will be to explore whether the delivery of bacteriochlorin photosensitisers to cancer cells can be enhanced by introducing quaternised nitrogen atoms to the meso-aryl ligands. , Thesis (MSc) -- Faculty of Science, Chemistry, 2024
- Full Text:
- Date Issued: 2024-10-11
Platform food delivery: a study on the labour process and emotional labour experienced by gig workers in the Eastern Cape food delivery sector
- Authors: Mutshewa, Taboka Botsang
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/466221 , vital:76708
- Description: As central to the gig economy, digital platforms are transforming the character of the modern economy. South Africa has seen the increased use of technology and the integration of technological changes into the labour market and labour process, including via digital platforms. The gig economy has entered a range of economic sectors in South Africa and elsewhere, including the service sector. Examples of digital platforms in this specific sector include Uber and Bolt for transportation, Sweep South for domestic help, and Mr D Food for food delivery. Undoubtedly, by inhibiting and sanctioning movements globally and locally, the COVID-19 pandemic contributed to the expansion of the gig economy in the service sector, as it restricted walk-in customers. The digital platform mediates the relationship between service sector workers and their clients and between workers and the companies operating the platforms. In this way, these technological platforms act as an ‘extra hand’ by, for example, hiring delivery workers in the first instance and then facilitating the delivery of products to customers. This thesis examines the food delivery sector in the gig economy in the Eastern Cape Province of South Africa. The digital platforms in the food sector allow consumers to place food orders at a restaurant of choice and deliver them to their doorstep in less than an hour, ensuring convenience, reliability and efficiency for restaurants and customers. However, understanding the gig economy involves identifying and unpacking the experiences and perspectives of the gig workers. In doing so, this thesis examines food delivery workers labouring for two different companies (Uber East and Mr D Foods) in two sites (Makhanda and Gqeberha). The main aim is to analyse how the digital platforms restructure the labour process in the gig economy and the emotional labour enacted by the delivery workers. The thesis draws upon labour process and emotional labour theory to pursue this primary aim. Research findings highlight a high level of precariousness and stress amongst food delivery workers as they work under algorithmic systems of labour control marked by surveillance and are constantly required to perform emotionally to maximise income. , Thesis (MSocSci) -- Faculty of Humanities, Sociology, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Mutshewa, Taboka Botsang
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/466221 , vital:76708
- Description: As central to the gig economy, digital platforms are transforming the character of the modern economy. South Africa has seen the increased use of technology and the integration of technological changes into the labour market and labour process, including via digital platforms. The gig economy has entered a range of economic sectors in South Africa and elsewhere, including the service sector. Examples of digital platforms in this specific sector include Uber and Bolt for transportation, Sweep South for domestic help, and Mr D Food for food delivery. Undoubtedly, by inhibiting and sanctioning movements globally and locally, the COVID-19 pandemic contributed to the expansion of the gig economy in the service sector, as it restricted walk-in customers. The digital platform mediates the relationship between service sector workers and their clients and between workers and the companies operating the platforms. In this way, these technological platforms act as an ‘extra hand’ by, for example, hiring delivery workers in the first instance and then facilitating the delivery of products to customers. This thesis examines the food delivery sector in the gig economy in the Eastern Cape Province of South Africa. The digital platforms in the food sector allow consumers to place food orders at a restaurant of choice and deliver them to their doorstep in less than an hour, ensuring convenience, reliability and efficiency for restaurants and customers. However, understanding the gig economy involves identifying and unpacking the experiences and perspectives of the gig workers. In doing so, this thesis examines food delivery workers labouring for two different companies (Uber East and Mr D Foods) in two sites (Makhanda and Gqeberha). The main aim is to analyse how the digital platforms restructure the labour process in the gig economy and the emotional labour enacted by the delivery workers. The thesis draws upon labour process and emotional labour theory to pursue this primary aim. Research findings highlight a high level of precariousness and stress amongst food delivery workers as they work under algorithmic systems of labour control marked by surveillance and are constantly required to perform emotionally to maximise income. , Thesis (MSocSci) -- Faculty of Humanities, Sociology, 2024
- Full Text:
- Date Issued: 2024-10-11
Post migration factors associated with elevated symptoms of posttraumatic stress disorder, depression, and anxiety, among refugees in Cape Town
- Authors: Mujuru, Agnes
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/465810 , vital:76655
- Description: There has been a heavy influx of refugees in South Africa due to wars, conflicts, political persecution, and economic recessions around the world. As a result, South Africa hosts the highest number of African refugees, who are susceptible to mental health problems because of their exposure to war, violence, and post migration stressors. The current study assessed post migration predictors of post-traumatic stress disorder (PTSD), depression and anxiety symptoms among refugees in Cape Town South Africa. A cross-sectional survey of refugees from war- and conflict-torn countries settled in Cape Town was conducted between February and May 2023. Study participants (N = 147) were selected using respondent driven sampling technique. Data were collected using a questionnaire made up of the Post-traumatic Stress Disorder Checklist (PCL-5), Patient Health Questionnaire (PHQ-9), Generalised Anxiety Disorder-7 (GAD-7), and the Post- Migration Difficulties Checklist (PMLDs), to assess PTSD, depression, anxiety and PMLDs, respectively. Descriptive and inferential statistics were used to analyse the questionnaire data. The prevalence of PTSD, anxiety and depression symptoms was 26.5%, 33.3% and 33.3%, respectively. Regression analyses identified discrimination, poor access to health services, and poor access to food as the major predictors of common mental disorders among refugees. The document-seeking process, unemployment stress, language difficulties, not getting help with welfare, fears of being sent home and isolation, were also associated with symptoms of mental health conditions. These results suggest that psychological distress symptoms are highly elevated among refugees and are associated with post-migration stressors. Mental health interventions for refugees should not only address psychological difficulties but also consider the socio-economic needs of refugees. , Thesis (MA) -- Faculty of Humanities, Psychology, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Mujuru, Agnes
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/465810 , vital:76655
- Description: There has been a heavy influx of refugees in South Africa due to wars, conflicts, political persecution, and economic recessions around the world. As a result, South Africa hosts the highest number of African refugees, who are susceptible to mental health problems because of their exposure to war, violence, and post migration stressors. The current study assessed post migration predictors of post-traumatic stress disorder (PTSD), depression and anxiety symptoms among refugees in Cape Town South Africa. A cross-sectional survey of refugees from war- and conflict-torn countries settled in Cape Town was conducted between February and May 2023. Study participants (N = 147) were selected using respondent driven sampling technique. Data were collected using a questionnaire made up of the Post-traumatic Stress Disorder Checklist (PCL-5), Patient Health Questionnaire (PHQ-9), Generalised Anxiety Disorder-7 (GAD-7), and the Post- Migration Difficulties Checklist (PMLDs), to assess PTSD, depression, anxiety and PMLDs, respectively. Descriptive and inferential statistics were used to analyse the questionnaire data. The prevalence of PTSD, anxiety and depression symptoms was 26.5%, 33.3% and 33.3%, respectively. Regression analyses identified discrimination, poor access to health services, and poor access to food as the major predictors of common mental disorders among refugees. The document-seeking process, unemployment stress, language difficulties, not getting help with welfare, fears of being sent home and isolation, were also associated with symptoms of mental health conditions. These results suggest that psychological distress symptoms are highly elevated among refugees and are associated with post-migration stressors. Mental health interventions for refugees should not only address psychological difficulties but also consider the socio-economic needs of refugees. , Thesis (MA) -- Faculty of Humanities, Psychology, 2024
- Full Text:
- Date Issued: 2024-10-11
Potential futures: land management decision making in the Albertinia-Herbertsdale area of the Gouritz Cluster Biosphere Reserve
- Johnson, Ryana Elizabeth Milne
- Authors: Johnson, Ryana Elizabeth Milne
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464823 , vital:76548
- Description: Land use change drives biodiversity losses, and UNESCO biosphere reserves serve as laboratories for solving complex problems in the uncertain Anthropocene geological era. Land users' decisions form turning points for land use, biodiversity conservation and future trajectories of land management. This qualitative study used grounded theory, one-on-one interviews and a futures thinking workshop to explore land user decision making in the mixed agricultural Herbertsdale- Albertinia area of the Gouritz Cluster Biosphere Reserve. The study included participants using a variety of land management approaches, ranging from conservation to intensive agriculture. This study found that land managers in the study area interact with multiple complex social-ecological systems, and land management outcomes can be unpredictable for diverse reasons. Informed by learning and risk mitigation as well as their motivation for their present and future, land users are integrating sustainable land management practices in their commercial land management decisions. Their risk adaptation strategies tend to be hands on, independent and practical, as well as action oriented. This can be limiting when adaptation requires abstract, collective or systemic changes. All the participants know that they are dependent on natural resources. They all value their community and social networks. They have a strong appetite for learning, and combine an understanding of the historical context of their land management with an understanding that positive futures will require dynamic and extensive changes at multiple scales. They desire more integrated land use planning at catchment and landscape scales. Collaboration and collaborative strategies emerged as important pathways to the desired future. These include landscape level planning, lobbying for political and legal change, building community, learning, sustainable land management and social integration. It emerged that giving people time to think about abstract or large scale issues is appreciated, and not currently routine. This provides a potential leverage point for collaborative environmental stewardship in this highly biodiverse region. , Thesis (MSc) -- Faculty of Science, Environmental Science, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Johnson, Ryana Elizabeth Milne
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464823 , vital:76548
- Description: Land use change drives biodiversity losses, and UNESCO biosphere reserves serve as laboratories for solving complex problems in the uncertain Anthropocene geological era. Land users' decisions form turning points for land use, biodiversity conservation and future trajectories of land management. This qualitative study used grounded theory, one-on-one interviews and a futures thinking workshop to explore land user decision making in the mixed agricultural Herbertsdale- Albertinia area of the Gouritz Cluster Biosphere Reserve. The study included participants using a variety of land management approaches, ranging from conservation to intensive agriculture. This study found that land managers in the study area interact with multiple complex social-ecological systems, and land management outcomes can be unpredictable for diverse reasons. Informed by learning and risk mitigation as well as their motivation for their present and future, land users are integrating sustainable land management practices in their commercial land management decisions. Their risk adaptation strategies tend to be hands on, independent and practical, as well as action oriented. This can be limiting when adaptation requires abstract, collective or systemic changes. All the participants know that they are dependent on natural resources. They all value their community and social networks. They have a strong appetite for learning, and combine an understanding of the historical context of their land management with an understanding that positive futures will require dynamic and extensive changes at multiple scales. They desire more integrated land use planning at catchment and landscape scales. Collaboration and collaborative strategies emerged as important pathways to the desired future. These include landscape level planning, lobbying for political and legal change, building community, learning, sustainable land management and social integration. It emerged that giving people time to think about abstract or large scale issues is appreciated, and not currently routine. This provides a potential leverage point for collaborative environmental stewardship in this highly biodiverse region. , Thesis (MSc) -- Faculty of Science, Environmental Science, 2024
- Full Text:
- Date Issued: 2024-10-11
Promoting Grade 9 mathematics teachers’ TPACK development through planning algebra lessons that integrate technology in Oshakati education circuit
- Authors: Angula, Mechtilde
- Date: 2024-10-11
- Subjects: Algebra Study and teaching (Secondary) Namibia Oshakati , Technological Pedagogical Content Knowledge , Educational technology , Education Social aspects Namibia , Culturally relevant pedagogy Namibia
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/463669 , vital:76430
- Description: The revised curriculum in Namibia highlights the integration of digital tools to help learners understand mathematics better. For this purpose, teachers need to possess Technological Pedagogical Content Knowledge (TPACK) to utilize technology effectively. However, using technology by itself does not guarantee better learning rather, it requires an understanding of how to integrate technology in teaching mathematics. Therefore, this case study explored Grade 9 mathematics teachers’ TPACK development through planning algebra lessons that integrate technology. An interpretive paradigm, supported by a pragmatic paradigm, underpins the study, and a qualitative case study approach was employed. The study purposively engaged ten Grade 9 mathematics teachers from four schools in Namibia. Demographic questionnaires, Semi-structured interviews, Reflective journals, notes from discussions, focus group interviews and document analysis were used to gain teachers’ insights on TPACK development. The study was guided by two educational theories: Bernstein's Sociology of Education (1971) and Bloom's Taxonomy of the Cognitive Domain (1956). Also, Mishra and Koehler’s TPACK framework (2009) was used to analyze the data. The findings showed that mathematics teachers had a positive view of technology integration in mathematics lessons and TPACK development through technology-integrated lesson planning, but they lacked the knowledge for planning lessons that integrate technology. Taking part in the intervention improved the selected mathematics teachers' understanding of TPACK, making them more confident about using technology in their teaching. The study also found different strategies to help teachers incorporate technology into their lessons, along with having a strong grasp of the subject and effective teaching methods. Based on these findings, it is suggested that in-service mathematics teachers take part in interventions focused on integrating technology into lesson planning. These interventions should demonstrate how technology can improve mathematics education and how it fits with both content and teaching methods. It is also recommended that these interventions emphasize the importance of Bloom's Taxonomy in using technology for mathematics education. The study concludes by suggesting further research on how planned lessons can be implemented in actual mathematics classrooms. , Thesis (MEd) -- Faculty of Education, Secondary and Post-School Education, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Angula, Mechtilde
- Date: 2024-10-11
- Subjects: Algebra Study and teaching (Secondary) Namibia Oshakati , Technological Pedagogical Content Knowledge , Educational technology , Education Social aspects Namibia , Culturally relevant pedagogy Namibia
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/463669 , vital:76430
- Description: The revised curriculum in Namibia highlights the integration of digital tools to help learners understand mathematics better. For this purpose, teachers need to possess Technological Pedagogical Content Knowledge (TPACK) to utilize technology effectively. However, using technology by itself does not guarantee better learning rather, it requires an understanding of how to integrate technology in teaching mathematics. Therefore, this case study explored Grade 9 mathematics teachers’ TPACK development through planning algebra lessons that integrate technology. An interpretive paradigm, supported by a pragmatic paradigm, underpins the study, and a qualitative case study approach was employed. The study purposively engaged ten Grade 9 mathematics teachers from four schools in Namibia. Demographic questionnaires, Semi-structured interviews, Reflective journals, notes from discussions, focus group interviews and document analysis were used to gain teachers’ insights on TPACK development. The study was guided by two educational theories: Bernstein's Sociology of Education (1971) and Bloom's Taxonomy of the Cognitive Domain (1956). Also, Mishra and Koehler’s TPACK framework (2009) was used to analyze the data. The findings showed that mathematics teachers had a positive view of technology integration in mathematics lessons and TPACK development through technology-integrated lesson planning, but they lacked the knowledge for planning lessons that integrate technology. Taking part in the intervention improved the selected mathematics teachers' understanding of TPACK, making them more confident about using technology in their teaching. The study also found different strategies to help teachers incorporate technology into their lessons, along with having a strong grasp of the subject and effective teaching methods. Based on these findings, it is suggested that in-service mathematics teachers take part in interventions focused on integrating technology into lesson planning. These interventions should demonstrate how technology can improve mathematics education and how it fits with both content and teaching methods. It is also recommended that these interventions emphasize the importance of Bloom's Taxonomy in using technology for mathematics education. The study concludes by suggesting further research on how planned lessons can be implemented in actual mathematics classrooms. , Thesis (MEd) -- Faculty of Education, Secondary and Post-School Education, 2024
- Full Text:
- Date Issued: 2024-10-11
Protecting and organising the apartheid and post-apartheid precarious municipal workforce: the Cape Town Municipal Workers Association and the South African Municipal Workers Union in Cape Town
- Authors: Mathekga, Jerry Mmanoko
- Date: 2024-10-11
- Subjects: African National Congress , COSATU , South African Municipal Workers Union , Apartheid South Africa , Municipal officials and employees South Africa Cape Town , Neoliberalism , Contracting out , Precarious employment
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/467072 , vital:76812 , DOI https://doi.org/10.21504/10962/467072
- Description: The contemporary, global expansion of precarious employment poses key challenges for unions based on workers in full-time, stable employment (i.e. workers in the so-called “Standard Employment Relationship” – SER). South African unions and federations like the Congress of South African Trade Unions (COSATU), have resolved to organise these workers for decades. Most unions have, however done little to put these intentions into effect, even though precarity threatens union survival. A notable exception amongst unions in both the state and private sectors is COSATU’s South African Municipal Workers Union (SAMWU). SAMWU has a long history of consistently acting to protect and organise precarious workers. This is the puzzle with which this thesis grapples: why has SAMWU been different? This question is examined through a focus on Cape Town, the city in which the union has the deepest roots: its main, immediate predecessor, the Cape Town Municipal Workers Association (CTMWA), was founded in Cape Town in 1918. Answering the question posed above requires examining the record: how has SAMWU – and before it, the CTMWA – protected and organise precarious workers in the municipal sector over time? And further, why did CTMWA and SAMWU act this way, when many others have not? The answers lie in the distinctive character of the organisation’s trade union identity, drawing on Richard Hyman’s work, which moves beyond broad labels (business unionism, political unionism, etc.) and normative prescriptions (what unions should, ideally, do) to develop a nuanced model of what predisposes, and enables, certain union choices, actions, and responses union. The popular power resources approach (PRA) to unions helps map the resources available to unions but cannot explain why unions use power resources in specific ways. The thesis argues that the evolving union identity of the CTMWA and SAMWU predisposed it to organising workers, and that this evolving identity has been shaped by the distinctive features of the Western Cape and its political traditions, a long history of multiple municipal labour markets in Cape Town, and the specificities of that city, including the black African / Coloured division, its independent left traditions, the relative weakness of the COSATU’s allies, the African National Congress (ANC) and the South African Communist Party (SACP), in local government, and the peculiar dynamics of municipal restructuring. This thesis draws on both labour history and industrial Sociology, arguing that a dialogue between these two disciplines enriches labour studies. This thesis draws on a wide range of primary sources, both historical and contemporary, examines historical processes and change, and engages in a dialogue between historical and sociological work. It argues for the need to historicise precarity, avoiding a “year zero” approach that treats it as a novel challenge for unions, and as reducible to neo-liberalism. It insists that labour responses are shaped by place and time, and so, for the need to balance macro-level discussions of trends with local specificities. It argues that notion of a sharp rupture between the surging new wave of unionism that started in South Africa in 1973, from which COSATU emerged, and the older traditions of registered unionism has been overstated. More attention needs to be paid to the imprint of the more radical registered unions, like CTMWA, on the new unionism. Rejecting pessimistic accounts that see unions as doomed by precarity, it draws attention to long histories of relatively successful and sustained union responses, like those of CTMWA/ SAMWU. However, it questions prescriptive approaches that centre on what unions should do, highlighting how evolving union identity shapes what unions can do. , Thesis (PhD) -- Faculty of Humanities, Sociology, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Mathekga, Jerry Mmanoko
- Date: 2024-10-11
- Subjects: African National Congress , COSATU , South African Municipal Workers Union , Apartheid South Africa , Municipal officials and employees South Africa Cape Town , Neoliberalism , Contracting out , Precarious employment
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/467072 , vital:76812 , DOI https://doi.org/10.21504/10962/467072
- Description: The contemporary, global expansion of precarious employment poses key challenges for unions based on workers in full-time, stable employment (i.e. workers in the so-called “Standard Employment Relationship” – SER). South African unions and federations like the Congress of South African Trade Unions (COSATU), have resolved to organise these workers for decades. Most unions have, however done little to put these intentions into effect, even though precarity threatens union survival. A notable exception amongst unions in both the state and private sectors is COSATU’s South African Municipal Workers Union (SAMWU). SAMWU has a long history of consistently acting to protect and organise precarious workers. This is the puzzle with which this thesis grapples: why has SAMWU been different? This question is examined through a focus on Cape Town, the city in which the union has the deepest roots: its main, immediate predecessor, the Cape Town Municipal Workers Association (CTMWA), was founded in Cape Town in 1918. Answering the question posed above requires examining the record: how has SAMWU – and before it, the CTMWA – protected and organise precarious workers in the municipal sector over time? And further, why did CTMWA and SAMWU act this way, when many others have not? The answers lie in the distinctive character of the organisation’s trade union identity, drawing on Richard Hyman’s work, which moves beyond broad labels (business unionism, political unionism, etc.) and normative prescriptions (what unions should, ideally, do) to develop a nuanced model of what predisposes, and enables, certain union choices, actions, and responses union. The popular power resources approach (PRA) to unions helps map the resources available to unions but cannot explain why unions use power resources in specific ways. The thesis argues that the evolving union identity of the CTMWA and SAMWU predisposed it to organising workers, and that this evolving identity has been shaped by the distinctive features of the Western Cape and its political traditions, a long history of multiple municipal labour markets in Cape Town, and the specificities of that city, including the black African / Coloured division, its independent left traditions, the relative weakness of the COSATU’s allies, the African National Congress (ANC) and the South African Communist Party (SACP), in local government, and the peculiar dynamics of municipal restructuring. This thesis draws on both labour history and industrial Sociology, arguing that a dialogue between these two disciplines enriches labour studies. This thesis draws on a wide range of primary sources, both historical and contemporary, examines historical processes and change, and engages in a dialogue between historical and sociological work. It argues for the need to historicise precarity, avoiding a “year zero” approach that treats it as a novel challenge for unions, and as reducible to neo-liberalism. It insists that labour responses are shaped by place and time, and so, for the need to balance macro-level discussions of trends with local specificities. It argues that notion of a sharp rupture between the surging new wave of unionism that started in South Africa in 1973, from which COSATU emerged, and the older traditions of registered unionism has been overstated. More attention needs to be paid to the imprint of the more radical registered unions, like CTMWA, on the new unionism. Rejecting pessimistic accounts that see unions as doomed by precarity, it draws attention to long histories of relatively successful and sustained union responses, like those of CTMWA/ SAMWU. However, it questions prescriptive approaches that centre on what unions should do, highlighting how evolving union identity shapes what unions can do. , Thesis (PhD) -- Faculty of Humanities, Sociology, 2024
- Full Text:
- Date Issued: 2024-10-11
Protecting stateless children in South Africa through nationality: a children’s rights approach
- Authors: Maziya, Nokwanda Takalanga
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466469 , vital:76733 , DOI https://doi.org/10.21504/10962/466469
- Description: This study investigates the role of nationality in protecting stateless children. Under interna-tional human rights law, all individuals, including stateless persons, are entitled to certain rights by virtue of being human. Consequently, stateless children should theoretically have access to fundamental rights such as education, healthcare, and social security, even without nationality. However, this study challenges the assumption that stateless children can access these rights merely because they are human. The study reveals that, in practice, stateless chil-dren struggle to access essential rights like education, healthcare, and social welfare without nationality. The study asserts that nationality is crucial for stateless children to access basic rights in South Africa. The study examines various treaties related to nationality and con-cludes that none impose a binding obligation on South Africa to confer nationality on state-less children. The study then draws on international children's rights principles such as the best interest of the child, the right to life, survival and development, and the right to non-discrimination to demonstrate that despite a clear obligation on South Africa in terms of trea-ty law to grant nationality to stateless, these principles, place limits on South Africa's exer-cise of sovereign power. This, in turn, makes way for granting nationality to stateless chil-dren. , Thesis (PhD) -- Faculty of Law, Law, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Maziya, Nokwanda Takalanga
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466469 , vital:76733 , DOI https://doi.org/10.21504/10962/466469
- Description: This study investigates the role of nationality in protecting stateless children. Under interna-tional human rights law, all individuals, including stateless persons, are entitled to certain rights by virtue of being human. Consequently, stateless children should theoretically have access to fundamental rights such as education, healthcare, and social security, even without nationality. However, this study challenges the assumption that stateless children can access these rights merely because they are human. The study reveals that, in practice, stateless chil-dren struggle to access essential rights like education, healthcare, and social welfare without nationality. The study asserts that nationality is crucial for stateless children to access basic rights in South Africa. The study examines various treaties related to nationality and con-cludes that none impose a binding obligation on South Africa to confer nationality on state-less children. The study then draws on international children's rights principles such as the best interest of the child, the right to life, survival and development, and the right to non-discrimination to demonstrate that despite a clear obligation on South Africa in terms of trea-ty law to grant nationality to stateless, these principles, place limits on South Africa's exer-cise of sovereign power. This, in turn, makes way for granting nationality to stateless chil-dren. , Thesis (PhD) -- Faculty of Law, Law, 2024
- Full Text:
- Date Issued: 2024-10-11
Realist evaluation cases of the uptake and use of citizen science tools for water quality management: Vaal-Triangle public primary schools teachers and Mpophomeni enviro-champs
- Authors: Madiba, Morakane Stephinah
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466406 , vital:76725 , DOI https://doi.org/10.21504/10962/466406
- Description: This study employs a theory-based approach to evaluate citizen science (CS) interventions in two distinct cases: the Mpophomeni enviro-champs and the Vaal-Triangle primary school teachers. These interventions were designed to foster social learning, enhance education or participants' understanding of water quality impacts, and promote community or public participation for improved water management. GroundTruth, a multidisciplinary consulting company with expertise in water resources and environmental engineering, collaborated as partners in these CS projects. Utilizing qualitative realist evaluation theory, the study delves into the intricate context-mechanismoutcome (CMO) configurations for each case, seeking depth insight into the outcomes of these citizen science initiatives. Data collection involved interviews, document analysis, and participant observations to construct a comprehensive understanding of the interventions' impact. In the case of the Vaal-Triangle primary school teachers, the CS intervention yielded positive results, significantly influencing teaching practices and instilling shared values for sustainable water quality management in both classrooms and the surrounding communities. However, the study revealed the need for continued evaluation and comprehensive dialogue among stakeholders, including teachers, school governing bodies, local municipalities, the Department of Basic Education, and the broader community to ensure the effectiveness, sustainability, and transformative potential of these interventions. In contrast, the Mpophomeni enviro-champs experienced a different set of outcomes. The CS intervention catalyzed numerous opportunities for the volunteers, forging a collaborative relationship between citizens and the government. Despite their socio-ecological vulnerability, these volunteers exhibited remarkable resilience and willingness to contribute, calling for formalization mechanisms such as remuneration and skill recognition to sustain and enhance their participation. This study provides insights into citizen science interventions, foregrounding volunteerism as a means of fostering fair and inclusive participation. It emphasizes the significance of combining social and classroom learning in achieving sustainable water quality management objectives. Furthermore, the research highlights the pivotal role of informed citizenship, which necessitates an understanding not only of environmental activism but also of effective political engagement to influence decision-making processes effectively. By challenging historical barriers and revealing new perspectives, this study offers a reflective thinking tool to advance transformative policy development in South Africa and beyond, promoting informed and responsible public participation in water quality management and fostering the sustainability of precious water resources. , Thesis (PhD) -- Faculty of Education, Secondary and Post-School Education, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Madiba, Morakane Stephinah
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466406 , vital:76725 , DOI https://doi.org/10.21504/10962/466406
- Description: This study employs a theory-based approach to evaluate citizen science (CS) interventions in two distinct cases: the Mpophomeni enviro-champs and the Vaal-Triangle primary school teachers. These interventions were designed to foster social learning, enhance education or participants' understanding of water quality impacts, and promote community or public participation for improved water management. GroundTruth, a multidisciplinary consulting company with expertise in water resources and environmental engineering, collaborated as partners in these CS projects. Utilizing qualitative realist evaluation theory, the study delves into the intricate context-mechanismoutcome (CMO) configurations for each case, seeking depth insight into the outcomes of these citizen science initiatives. Data collection involved interviews, document analysis, and participant observations to construct a comprehensive understanding of the interventions' impact. In the case of the Vaal-Triangle primary school teachers, the CS intervention yielded positive results, significantly influencing teaching practices and instilling shared values for sustainable water quality management in both classrooms and the surrounding communities. However, the study revealed the need for continued evaluation and comprehensive dialogue among stakeholders, including teachers, school governing bodies, local municipalities, the Department of Basic Education, and the broader community to ensure the effectiveness, sustainability, and transformative potential of these interventions. In contrast, the Mpophomeni enviro-champs experienced a different set of outcomes. The CS intervention catalyzed numerous opportunities for the volunteers, forging a collaborative relationship between citizens and the government. Despite their socio-ecological vulnerability, these volunteers exhibited remarkable resilience and willingness to contribute, calling for formalization mechanisms such as remuneration and skill recognition to sustain and enhance their participation. This study provides insights into citizen science interventions, foregrounding volunteerism as a means of fostering fair and inclusive participation. It emphasizes the significance of combining social and classroom learning in achieving sustainable water quality management objectives. Furthermore, the research highlights the pivotal role of informed citizenship, which necessitates an understanding not only of environmental activism but also of effective political engagement to influence decision-making processes effectively. By challenging historical barriers and revealing new perspectives, this study offers a reflective thinking tool to advance transformative policy development in South Africa and beyond, promoting informed and responsible public participation in water quality management and fostering the sustainability of precious water resources. , Thesis (PhD) -- Faculty of Education, Secondary and Post-School Education, 2024
- Full Text:
- Date Issued: 2024-10-11
Redefinition of a refugee during conditions of disaster uncertainty of COVID19 in South Africa and beyond
- Authors: Maguire, Kelly Ann
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/461841 , vital:76244
- Description: Access restricited. Expected release date 2026. , Thesis (Msc (Pharmacy)) -- Faculty of Pharmacy, Pharmacy, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Maguire, Kelly Ann
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/461841 , vital:76244
- Description: Access restricited. Expected release date 2026. , Thesis (Msc (Pharmacy)) -- Faculty of Pharmacy, Pharmacy, 2024
- Full Text:
- Date Issued: 2024-10-11
Relationship between oil price changes and the South African stock market returns: a nonlinear ARDL analysis
- Authors: Habana, Athenkosi
- Date: 2024-10-11
- Subjects: Stock market index South Africa , Stock exchanges South Africa , Petroleum products Prices South Africa , Autoregression (Statistics) , JSE Securities Exchange South Africa
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/462713 , vital:76328
- Description: Understanding the factors that influence oil price volatility and how they affect the stock market is crucial for decision-making, planning, and forecasting by governments, companies, and individuals. The aim of this study is to analyze the relationship between oil prices and stock market returns of selected JSE stock indices. A nonlinear ARDL model is used to study the interaction between changes in oil prices and the South African stock market. Monthly data covering the period from January 2010 to December 2022 is utilized in the study. The main findings of the study show that in the short run negative changes in oil prices have a statistically significant positive impact that on stock returns of the All-Share, Financials and Resources indices, while it is insignificant for the Industrials index stock returns. On the other hand, positive changes in oil prices have a negative and insignificant impact on all the stock returns of the indices. Therefore, in the short-run there is no nonlinear relationship between oil prices and the stock returns of the indices. In the long-run, the impact of oil prices on stock returns of the All Share, Financials and Resources indices is nonlinear or asymmetric. The impact of oil price changes on the stock indices varies across the indices. An increase in oil prices has a negative and statistically significant impact on stock returns of the All Share, Financials and Resources index. Conversely, a decrease in oil prices has a positive and significant impact on All Share, Financials and Resources index stock returns in the long-run. The impact of positive and negative changes in oil prices is insignificant for the Industrials index stock returns. Therefore, these finding makes it possible for investors or portfolio managers to better mitigate the negative consequences of unforeseen events and adapt their investment plans to hedge against variations in the price of oil. , Thesis (MCom) -- Faculty of Commerce, Economics and Economic History, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Habana, Athenkosi
- Date: 2024-10-11
- Subjects: Stock market index South Africa , Stock exchanges South Africa , Petroleum products Prices South Africa , Autoregression (Statistics) , JSE Securities Exchange South Africa
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/462713 , vital:76328
- Description: Understanding the factors that influence oil price volatility and how they affect the stock market is crucial for decision-making, planning, and forecasting by governments, companies, and individuals. The aim of this study is to analyze the relationship between oil prices and stock market returns of selected JSE stock indices. A nonlinear ARDL model is used to study the interaction between changes in oil prices and the South African stock market. Monthly data covering the period from January 2010 to December 2022 is utilized in the study. The main findings of the study show that in the short run negative changes in oil prices have a statistically significant positive impact that on stock returns of the All-Share, Financials and Resources indices, while it is insignificant for the Industrials index stock returns. On the other hand, positive changes in oil prices have a negative and insignificant impact on all the stock returns of the indices. Therefore, in the short-run there is no nonlinear relationship between oil prices and the stock returns of the indices. In the long-run, the impact of oil prices on stock returns of the All Share, Financials and Resources indices is nonlinear or asymmetric. The impact of oil price changes on the stock indices varies across the indices. An increase in oil prices has a negative and statistically significant impact on stock returns of the All Share, Financials and Resources index. Conversely, a decrease in oil prices has a positive and significant impact on All Share, Financials and Resources index stock returns in the long-run. The impact of positive and negative changes in oil prices is insignificant for the Industrials index stock returns. Therefore, these finding makes it possible for investors or portfolio managers to better mitigate the negative consequences of unforeseen events and adapt their investment plans to hedge against variations in the price of oil. , Thesis (MCom) -- Faculty of Commerce, Economics and Economic History, 2024
- Full Text:
- Date Issued: 2024-10-11
Research-informed development of comprehensible isiXhosa teaching material: the Department of Basic Education Mental Starters doubling and halving unit
- Authors: Booi, Tabisa
- Date: 2024-10-11
- Subjects: Native language and education South Africa , Mathematics Translating South Africa , South Africa. Department of Basic Education , Translanguaging (Linguistics) , Mathematics Study and teaching (Elementary) South Africa
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/463680 , vital:76431
- Description: One of the challenges faced by schools that teach in isiXhosa in the Foundation Phase is the impact of nature of language used in the early-grade mathematics classroom. This is the focus of this research study. Despite numerous programs addressing the poor performance in mathematics, a significant majority of interventions are presented in English, creating barriers for learners and teachers using their native languages. While the Language in Education Policy allows for home language instruction in isiXhosa, the translation of materials often contains distortion in meaning and unfamiliar terms, complicating comprehension for indigenous language learners. Motivated by concerns over low mathematics performance, as highlighted in TIMSS (2019), and my personal experiences in teaching Foundation Phase mathematics in isiXhosa at a rural primary school, this study explores the challenges arising from using translated materials. The use of mediating materials in isiXhosa can be hindered by unfamiliar terms and distortion in meaning. For this reason, I adopted a translanguaging approach, incorporating transliteration between English and isiXhosa, especially in mathematics teaching. Grounded in the pragmatism paradigm, this qualitative design research unfolds in an isiXhosa medium primary school in Makhanda. The investigation centers first on document analysis of the Doubling and Halving unit in the Mental Starters Assessment Programme (MSAP) Teacher Guide (in English and isiXhosa), and then focuses on the teaching of two grade 3 classes, in isiXhosa, using the MSAP Doubling and Halving teaching sequence. Two grade 3 teachers and their principal participate as critical friends. The key research questions are: (1) What are the enablers and constraints that are experienced by the teacher during the mediation of the doubling and halving calculating strategies in isiXhosa?; (2) What are the key terms and phrases (vocabulary) needed to teach doubling and halving in isiXhosa?; (3) What are the perspectives and pedagogical insights of the critical friends on the isiXhosa vocabulary that was developed? The research unfolds in multiple stages, beginning with a document analysis of the MSAP using Toury’s Descriptive Translation Studies. Subsequently, I adapt eight lesson starters for doubling and halving, implementing them across two grade 3 classes in a double action research cycle. Focus group discussions with critical friends, aided by video recordings for stimulated recall, provide valuable insights. Data collected throughout these stages are analyzed through the lens of Vygotsky’s Socio-Cultural theory, contributing to a comprehensive understanding of the challenges and potential solutions in this educational context. , Thesis (MEd) -- Faculty of Education, Primary and Early Childhood Education, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Booi, Tabisa
- Date: 2024-10-11
- Subjects: Native language and education South Africa , Mathematics Translating South Africa , South Africa. Department of Basic Education , Translanguaging (Linguistics) , Mathematics Study and teaching (Elementary) South Africa
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/463680 , vital:76431
- Description: One of the challenges faced by schools that teach in isiXhosa in the Foundation Phase is the impact of nature of language used in the early-grade mathematics classroom. This is the focus of this research study. Despite numerous programs addressing the poor performance in mathematics, a significant majority of interventions are presented in English, creating barriers for learners and teachers using their native languages. While the Language in Education Policy allows for home language instruction in isiXhosa, the translation of materials often contains distortion in meaning and unfamiliar terms, complicating comprehension for indigenous language learners. Motivated by concerns over low mathematics performance, as highlighted in TIMSS (2019), and my personal experiences in teaching Foundation Phase mathematics in isiXhosa at a rural primary school, this study explores the challenges arising from using translated materials. The use of mediating materials in isiXhosa can be hindered by unfamiliar terms and distortion in meaning. For this reason, I adopted a translanguaging approach, incorporating transliteration between English and isiXhosa, especially in mathematics teaching. Grounded in the pragmatism paradigm, this qualitative design research unfolds in an isiXhosa medium primary school in Makhanda. The investigation centers first on document analysis of the Doubling and Halving unit in the Mental Starters Assessment Programme (MSAP) Teacher Guide (in English and isiXhosa), and then focuses on the teaching of two grade 3 classes, in isiXhosa, using the MSAP Doubling and Halving teaching sequence. Two grade 3 teachers and their principal participate as critical friends. The key research questions are: (1) What are the enablers and constraints that are experienced by the teacher during the mediation of the doubling and halving calculating strategies in isiXhosa?; (2) What are the key terms and phrases (vocabulary) needed to teach doubling and halving in isiXhosa?; (3) What are the perspectives and pedagogical insights of the critical friends on the isiXhosa vocabulary that was developed? The research unfolds in multiple stages, beginning with a document analysis of the MSAP using Toury’s Descriptive Translation Studies. Subsequently, I adapt eight lesson starters for doubling and halving, implementing them across two grade 3 classes in a double action research cycle. Focus group discussions with critical friends, aided by video recordings for stimulated recall, provide valuable insights. Data collected throughout these stages are analyzed through the lens of Vygotsky’s Socio-Cultural theory, contributing to a comprehensive understanding of the challenges and potential solutions in this educational context. , Thesis (MEd) -- Faculty of Education, Primary and Early Childhood Education, 2024
- Full Text:
- Date Issued: 2024-10-11
Restless imagination: material, urban space and contemporary art practices in postcolonial Harare
- Authors: Zhang, Lifang
- Date: 2024-10-11
- Subjects: African art , Art, Modern 21st century , Materiality , Zimbabwean art , Public spaces in art Zimbabwe Harare , Found objects (Art)
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/467061 , vital:76811 , DOI htps://doi.org/10.21504/10962/467061
- Description: The use of everyday objects as art materials has evolved into a contemporary phenomenon in Africa, deeply rooted in specific contexts and possessing global relevance. Despite limited scholarly attention, existing discussions tend to revolve around individual artists or particular mediums. Many discourses are associated with either the prevailing universalist perspective that views the trend as Western avant-garde derivation or the reductionist narrative that attributes it merely to local material scarcity. There exists a critical need to investigate historical genealogies and explore the theoretical frameworks essential for comprehending this phenomenon. Through a combination of visual analysis, fieldwork and interviews, this thesis conducts an in-depth examination of the use of found materials in Zimbabwe, exploring its historiography, mechanism, impact, and visual achievements. This thesis situates the investigation in postcolonial Harare, the city that profoundly shaped the evolution of the phenomenon of using found materials. Regarding timeframe, this thesis examines contemporary Zimbabwean artists’ practices, with a special emphasis on the period following the Redefinitions movement in the early 2000s. However, it also explores the pioneering material innovations of Tapfuma Gutsa and Keston Beaton, as well as analyses the importance of the Pachipamwe workshop between the 1980s and 1990s. Among the artists, it highlights those who consistently engage with found materials and delve into their interactions with urban spaces in their practices. With the city as the analytical framework, this thesis draws on debates centring on contemporary African art and theories about materiality and urban studies. Approaching found materials as the materiality of both art and the city, it reveals a convergence of various interrelated artistic practices in Harare. The multidimensional relationships are manifested in the artistic processes, where the collection of materials, the creation of artworks, and collaboration with diverse urban groups, are intricately linked to urban spaces in Harare. By unfolding this process and emphasising the labour of artists, this thesis transcends conventional perceptions of artworks as mere visual objects, revealing the societal and spatial interactions inherent in artistic practices involving found materials. This thesis also explores the visual and semantical interactions between art and the city, centring on a curated array of artworks which is not merely a visual representation or reflection of the city but also provides critical thoughts on and dialogues with the city, as well as (re)imaginations and aspirations of the urban landscape. The relationship between art and the city is further deepened through iii artistic practices, extending beyond the creation of artworks and involving art infrastructure building in Harare. This thesis conceptualises artists’ practices of working with found material as restless imagination, a term drawn from the name of the city, which refers to “no one sleeps” in the Shona language. The restlessness embedded in its naming has characterised the city in various dimensions and across time, with the haunting colonial legacy, ongoing urban crises, ubiquitous movements and the ordinary people’s unwavering efforts for liberation and survival. Artists residing in postcolonial Harare also adopt and cultivate restlessness as a working strategy not only to cope with but also to transgress such conditions. The evolution of found materials has been unfolded through a continuous process of restless imagination and innovative manoeuvres, which are embodied in the continual re-imagination of the convention of art materials, the expressive capacities of specific materials, and a commitment to labour throughout the transformative process. This open-ended though productive process of exploration perpetuates and extends to the re-imagination and reclaiming of urban spaces, transforming them into artistic spaces that foster artistic creation and the reproduction of artists and imaginations. This thesis argues the potential framing and comprehension of Harare city as the site of restless imagination pursued, embodied and materialised by artists through their artwork and engagement with urban spaces. Contemporary Zimbabwean artists have redefined their artistic practices, interacting with the materiality of everyday urban life, urban matters, urban spaces, and urban communities, and, concurrently, the relationship between art and city, art and society. By doing so, they open up space for possibilities to refashion the restless city, negotiate urban citizenship, and recreate themselves as agentive subjects in postcolonial Harare. It could be argued that artists, as urban citizens, akin to other residents grappling with everyday life in the city, also exercise their arts of citizenship through their creative innovations in artistic expression and practices. Therefore, this thesis not only delves into the contextualisation of artistic practices in Harare but also contributes to broader discussions on everyday practices in African cities through the lens of art. , Thesis (PhD) -- Faculty of Humanities, Fine Art, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Zhang, Lifang
- Date: 2024-10-11
- Subjects: African art , Art, Modern 21st century , Materiality , Zimbabwean art , Public spaces in art Zimbabwe Harare , Found objects (Art)
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/467061 , vital:76811 , DOI htps://doi.org/10.21504/10962/467061
- Description: The use of everyday objects as art materials has evolved into a contemporary phenomenon in Africa, deeply rooted in specific contexts and possessing global relevance. Despite limited scholarly attention, existing discussions tend to revolve around individual artists or particular mediums. Many discourses are associated with either the prevailing universalist perspective that views the trend as Western avant-garde derivation or the reductionist narrative that attributes it merely to local material scarcity. There exists a critical need to investigate historical genealogies and explore the theoretical frameworks essential for comprehending this phenomenon. Through a combination of visual analysis, fieldwork and interviews, this thesis conducts an in-depth examination of the use of found materials in Zimbabwe, exploring its historiography, mechanism, impact, and visual achievements. This thesis situates the investigation in postcolonial Harare, the city that profoundly shaped the evolution of the phenomenon of using found materials. Regarding timeframe, this thesis examines contemporary Zimbabwean artists’ practices, with a special emphasis on the period following the Redefinitions movement in the early 2000s. However, it also explores the pioneering material innovations of Tapfuma Gutsa and Keston Beaton, as well as analyses the importance of the Pachipamwe workshop between the 1980s and 1990s. Among the artists, it highlights those who consistently engage with found materials and delve into their interactions with urban spaces in their practices. With the city as the analytical framework, this thesis draws on debates centring on contemporary African art and theories about materiality and urban studies. Approaching found materials as the materiality of both art and the city, it reveals a convergence of various interrelated artistic practices in Harare. The multidimensional relationships are manifested in the artistic processes, where the collection of materials, the creation of artworks, and collaboration with diverse urban groups, are intricately linked to urban spaces in Harare. By unfolding this process and emphasising the labour of artists, this thesis transcends conventional perceptions of artworks as mere visual objects, revealing the societal and spatial interactions inherent in artistic practices involving found materials. This thesis also explores the visual and semantical interactions between art and the city, centring on a curated array of artworks which is not merely a visual representation or reflection of the city but also provides critical thoughts on and dialogues with the city, as well as (re)imaginations and aspirations of the urban landscape. The relationship between art and the city is further deepened through iii artistic practices, extending beyond the creation of artworks and involving art infrastructure building in Harare. This thesis conceptualises artists’ practices of working with found material as restless imagination, a term drawn from the name of the city, which refers to “no one sleeps” in the Shona language. The restlessness embedded in its naming has characterised the city in various dimensions and across time, with the haunting colonial legacy, ongoing urban crises, ubiquitous movements and the ordinary people’s unwavering efforts for liberation and survival. Artists residing in postcolonial Harare also adopt and cultivate restlessness as a working strategy not only to cope with but also to transgress such conditions. The evolution of found materials has been unfolded through a continuous process of restless imagination and innovative manoeuvres, which are embodied in the continual re-imagination of the convention of art materials, the expressive capacities of specific materials, and a commitment to labour throughout the transformative process. This open-ended though productive process of exploration perpetuates and extends to the re-imagination and reclaiming of urban spaces, transforming them into artistic spaces that foster artistic creation and the reproduction of artists and imaginations. This thesis argues the potential framing and comprehension of Harare city as the site of restless imagination pursued, embodied and materialised by artists through their artwork and engagement with urban spaces. Contemporary Zimbabwean artists have redefined their artistic practices, interacting with the materiality of everyday urban life, urban matters, urban spaces, and urban communities, and, concurrently, the relationship between art and city, art and society. By doing so, they open up space for possibilities to refashion the restless city, negotiate urban citizenship, and recreate themselves as agentive subjects in postcolonial Harare. It could be argued that artists, as urban citizens, akin to other residents grappling with everyday life in the city, also exercise their arts of citizenship through their creative innovations in artistic expression and practices. Therefore, this thesis not only delves into the contextualisation of artistic practices in Harare but also contributes to broader discussions on everyday practices in African cities through the lens of art. , Thesis (PhD) -- Faculty of Humanities, Fine Art, 2024
- Full Text:
- Date Issued: 2024-10-11
RU sleepy? - sleep/wake characteristics and sleep quality among undergraduate students attending Rhodes University
- Authors: Young, Celine Brittany
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464776 , vital:76544
- Description: Background: University students, specifically older adolescents and young adults, are at high risk of insufficient and poor-quality sleep due to age-related biological changes converging with several systemic factors unique to the university context. These include but are not limited to freedom and independence, communal living environments, academic demands and associated stress, erratic schedules, and high technology use. While there has been extensive research on sleep quality in students in other parts of the world, there has been comparatively less in South Africa, which may present unique contextual influencing factors. Thus, this study aimed to characterise sleep/wake characteristics and sleep quality in a sample of undergraduate students attending a South African University. Additionally, the study aimed to determine the impact of certain demographic factors on sleep quality in the students. Lastly, the current study aimed to determine what factors may influence the students' sleep quality. Method: This study adopted a cross-sectional design and explored sleep quality and sleep/wake characteristics (e.g., bedtimes, rise times, sleep duration, sleep latency, etc.) through an online survey circulated amongst undergraduate students via Rhodes university email platforms and student social media pages. The testing period started on 15 August 2022 and continued until 8 October 2022. The survey consisted of three main sections: (1) socio-demographic factors; (2) the Pittsburgh Sleep Quality Index (PSQI); (3) an open-ended question that asked students to comment on the factors which they felt may be influencing their sleep over the previous month. Results: 393 students participated in this study, which corresponds to a response rate of 6.30%. The results revealed notable levels of poor sleep quality (mean global score of 9.79 (±3.36)) and a high prevalence of poor sleepers within the whole sample (over 90%), as well as across different demographic groups. Analysis indicated poor overall sleep quality, and concerning sleep/wake characteristics, such as, bedtimes, rise times, sleep latency, time in bed, habitual sleep efficiency, sleep duration, etc. Additionally, participants reported extended sleep latencies and difficulties initiating sleep within 30 minutes. Daytime dysfunction was prominent, indicating challenges in daily functioning. Demographic comparisons revealed that male students generally reported better subjective sleep quality and lower global PSQI scores than female students, with 2 females presenting with poorer sleep quality overall. Students living in university residences reported significantly later bedtimes and shorter sleep durations than off- campus students. Regarding year of study, third-year students reported better subjective sleep quality, longer times in bed, longer sleep durations and overall better sleep quality than first- and second-year students. Regarding funding mechanisms, students on the National Students Financial Aid Scheme had significantly higher subjective sleep quality scores but later bedtimes than students in the "other" funding groups. Thematic analysis revealed that several self-reported factors impacted student sleep negatively. Mental health issues were the most commonly cited theme (26.72% of students), which included anxiety, stress, worry, and overthinking. University-related factors were the second most frequently cited theme (25.49% encompassing academics, funding, and navigating university life). Environmental influences comprised of issues with noise, particularly in university residences, weather, and lighting. Discussion: In sum, the results of this study indicate that in this sample, the drivers of poor sleep quality seemed to be late bedtimes, early rise times, prolonged sleep latency, frequent night awakenings, and overall short sleep duration, all of which were driven by several systemic factors. These findings underscore the importance of assessing sleep health beyond just sleep duration and indicate compromised sleep health within this population, evidenced by high levels of daytime dysfunction due to inadequate and poor-quality sleep. The challenges faced by university students extend across various aspects of their lives, including sleep health, with poor sleep quality and insufficient sleep having significant implications for academic performance, mental health, and overall well-being as they transition into adulthood. , Thesis (MSc) -- Faculty of Science, Human Kinetics and Ergonomics, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Young, Celine Brittany
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464776 , vital:76544
- Description: Background: University students, specifically older adolescents and young adults, are at high risk of insufficient and poor-quality sleep due to age-related biological changes converging with several systemic factors unique to the university context. These include but are not limited to freedom and independence, communal living environments, academic demands and associated stress, erratic schedules, and high technology use. While there has been extensive research on sleep quality in students in other parts of the world, there has been comparatively less in South Africa, which may present unique contextual influencing factors. Thus, this study aimed to characterise sleep/wake characteristics and sleep quality in a sample of undergraduate students attending a South African University. Additionally, the study aimed to determine the impact of certain demographic factors on sleep quality in the students. Lastly, the current study aimed to determine what factors may influence the students' sleep quality. Method: This study adopted a cross-sectional design and explored sleep quality and sleep/wake characteristics (e.g., bedtimes, rise times, sleep duration, sleep latency, etc.) through an online survey circulated amongst undergraduate students via Rhodes university email platforms and student social media pages. The testing period started on 15 August 2022 and continued until 8 October 2022. The survey consisted of three main sections: (1) socio-demographic factors; (2) the Pittsburgh Sleep Quality Index (PSQI); (3) an open-ended question that asked students to comment on the factors which they felt may be influencing their sleep over the previous month. Results: 393 students participated in this study, which corresponds to a response rate of 6.30%. The results revealed notable levels of poor sleep quality (mean global score of 9.79 (±3.36)) and a high prevalence of poor sleepers within the whole sample (over 90%), as well as across different demographic groups. Analysis indicated poor overall sleep quality, and concerning sleep/wake characteristics, such as, bedtimes, rise times, sleep latency, time in bed, habitual sleep efficiency, sleep duration, etc. Additionally, participants reported extended sleep latencies and difficulties initiating sleep within 30 minutes. Daytime dysfunction was prominent, indicating challenges in daily functioning. Demographic comparisons revealed that male students generally reported better subjective sleep quality and lower global PSQI scores than female students, with 2 females presenting with poorer sleep quality overall. Students living in university residences reported significantly later bedtimes and shorter sleep durations than off- campus students. Regarding year of study, third-year students reported better subjective sleep quality, longer times in bed, longer sleep durations and overall better sleep quality than first- and second-year students. Regarding funding mechanisms, students on the National Students Financial Aid Scheme had significantly higher subjective sleep quality scores but later bedtimes than students in the "other" funding groups. Thematic analysis revealed that several self-reported factors impacted student sleep negatively. Mental health issues were the most commonly cited theme (26.72% of students), which included anxiety, stress, worry, and overthinking. University-related factors were the second most frequently cited theme (25.49% encompassing academics, funding, and navigating university life). Environmental influences comprised of issues with noise, particularly in university residences, weather, and lighting. Discussion: In sum, the results of this study indicate that in this sample, the drivers of poor sleep quality seemed to be late bedtimes, early rise times, prolonged sleep latency, frequent night awakenings, and overall short sleep duration, all of which were driven by several systemic factors. These findings underscore the importance of assessing sleep health beyond just sleep duration and indicate compromised sleep health within this population, evidenced by high levels of daytime dysfunction due to inadequate and poor-quality sleep. The challenges faced by university students extend across various aspects of their lives, including sleep health, with poor sleep quality and insufficient sleep having significant implications for academic performance, mental health, and overall well-being as they transition into adulthood. , Thesis (MSc) -- Faculty of Science, Human Kinetics and Ergonomics, 2024
- Full Text:
- Date Issued: 2024-10-11
Screening and characterisation of novel compounds and their derivatives from South African medicinal plants against triple negative breast cancer cells
- Authors: Nyemba, Getrude Rutendo
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/463952 , vital:76460
- Description: Access restricted. Expected release in 2026. , Thesis (MSc) -- Faculty of Science, Biochemistry, Microbiology & Bioinformatics, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Nyemba, Getrude Rutendo
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/463952 , vital:76460
- Description: Access restricted. Expected release in 2026. , Thesis (MSc) -- Faculty of Science, Biochemistry, Microbiology & Bioinformatics, 2024
- Full Text:
- Date Issued: 2024-10-11
Screening for inhibitors of the Mycobacterium tuberculosis DnaK-DnaJ-GrpE complex
- Authors: John, Ruth Omoti
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466491 , vital:76735
- Description: Restricted access. Expected release in 2026. , Thesis (PhD) -- Faculty of Science, Biochemistry, Microbiology and Bioinformatics, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: John, Ruth Omoti
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466491 , vital:76735
- Description: Restricted access. Expected release in 2026. , Thesis (PhD) -- Faculty of Science, Biochemistry, Microbiology and Bioinformatics, 2024
- Full Text:
- Date Issued: 2024-10-11
Search for acrylonitrile-based inhibitors of SAR-Cov-19 main and papain-like proteases through covalent docking and high-throughput virtual screening
- Authors: Ntantiso, Yamkela
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/463941 , vital:76459
- Description: The sudden outbreak of SARS-CoV-2 formerly known as the 2019 novel coronavirus (2019-nCoV) quickly turned into a pandemic of coronavirus disease 2019 (COVID-19), the scale of which has never been seen before. High infection rates and mortality from COVID-19 placed pressure on global health services, and this has been to the detriment of the global economy. However, treatment options for COVID-19 are still very limited; hence, it is now as important as ever that researchers explore searching for new compounds with pharmacokinetic properties that inhibit the two COVID proteases - the main protease (Mpro) and the papain-like protease (PLpro). The main protease is a cysteine protease; as such, it is susceptible to permanent inhibition by reactive species (warheads) that may covalently bind to cysteine residues. One such class of compounds is acrylonitriles, in which the reactive acrylonitrile is reactive towards cysteine through a Michael addition reaction. The resulting covalent interaction is permanent and inactivates the cysteine residue and hence the protease within the context of the COVID-19 life-cycle. In this context, this study seeks to utilize computational-based approaches to identify acrylonitrile-based inhibitors of coronavirus drug targets. To do this, the ZINC database has been screened for compounds containing acrylonitrile functionality, due to its known nature as a warhead that binds to cysteine residues. Pharmacokinetic properties are computed to evaluate the viability of identified inhibitors, and covalent and non-covalent molecular docking approaches to the Mpro enzyme crystal structure have also been used to assess the identified systems. To gather more information and evaluate the most promising systems, a subset of the most promising compounds have been subjected to molecular dynamics simulation (for both covalently bound and non-covalently bound systems). , Thesis (MSc) -- Faculty of Science, Biochemistry, Microbiology & Bioinformatics, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Ntantiso, Yamkela
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/463941 , vital:76459
- Description: The sudden outbreak of SARS-CoV-2 formerly known as the 2019 novel coronavirus (2019-nCoV) quickly turned into a pandemic of coronavirus disease 2019 (COVID-19), the scale of which has never been seen before. High infection rates and mortality from COVID-19 placed pressure on global health services, and this has been to the detriment of the global economy. However, treatment options for COVID-19 are still very limited; hence, it is now as important as ever that researchers explore searching for new compounds with pharmacokinetic properties that inhibit the two COVID proteases - the main protease (Mpro) and the papain-like protease (PLpro). The main protease is a cysteine protease; as such, it is susceptible to permanent inhibition by reactive species (warheads) that may covalently bind to cysteine residues. One such class of compounds is acrylonitriles, in which the reactive acrylonitrile is reactive towards cysteine through a Michael addition reaction. The resulting covalent interaction is permanent and inactivates the cysteine residue and hence the protease within the context of the COVID-19 life-cycle. In this context, this study seeks to utilize computational-based approaches to identify acrylonitrile-based inhibitors of coronavirus drug targets. To do this, the ZINC database has been screened for compounds containing acrylonitrile functionality, due to its known nature as a warhead that binds to cysteine residues. Pharmacokinetic properties are computed to evaluate the viability of identified inhibitors, and covalent and non-covalent molecular docking approaches to the Mpro enzyme crystal structure have also been used to assess the identified systems. To gather more information and evaluate the most promising systems, a subset of the most promising compounds have been subjected to molecular dynamics simulation (for both covalently bound and non-covalently bound systems). , Thesis (MSc) -- Faculty of Science, Biochemistry, Microbiology & Bioinformatics, 2024
- Full Text:
- Date Issued: 2024-10-11
Sediment and associated phosphorus dynamics in meandering floodplain wetlands in the Tsitsa River catchment
- Authors: Schlegel, Philippa Kirsten
- Date: 2024-10-11
- Subjects: Sediments (Geology) , Phosphorus , Sedimentation and deposition , Ecosystem services Law and legislation South Africa , Arid regions South Africa
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466860 , vital:76793 , DOI https://doi.org/10.21504/10962/466860
- Description: A key function of floodplain wetlands systems is their ability to remove and store sediments and associated particulates (such as nutrients, organic carbon, and contaminants) from water, thus improving water quality for downstream ecosystems and water users. Increases in sediment and nutrient inputs to drainage networks pose a serious challenge to integrated resource management. These issues can be partly mitigated through natural buffering solutions along drainage networks, such as preserving essential wetland systems like floodplains. However, their trapping efficiency and storage timescales are uncertain. Although a large body of international knowledge and literature has advanced our understanding of river-floodplain systems and the ecosystem services that they provide, the factors determining their likelihood and effectiveness in supplying those regulatory ecosystem services have not been extensively and scientifically tested in floodplain systems in South Africa. This research aimed to describe and quantify the regulatory ecosystem services related to sediment and phosphorus buffering dynamics of two meandering floodplain systems in the Eastern Cape, South Africa. The study examined the geomorphology, sedimentology, and historical rates of sediment and associated phosphorus accumulation and release in the two floodplain systems. These systems varied in their morphometric features, size, catchment location, and predominant land use, providing a diverse range of characteristics. A comparative analysis was conducted between the two systems to understand the influence of local and catchment-scale factors. Time-averaged suspended sediment samples from the two wetlands were used to compare suspended sediment and associated total phosphorous fluxes over annual scales. Although both floodplains were net depositional during the study period, contemporary suspended sediment mass balance calculations suggested that the relatively larger Minnehaha floodplain system (~1.5 km²) situated in a significantly smaller catchment (~40 km²) had notably higher sediment and associated phosphorus trapping efficiencies of 44 % and 49 % respectively, compared to 16 % and 8 % for the relatively small Gatberg floodplain system (~0.3 km2) situated in a much larger catchment (~135 km²). This variability is attributed to the interaction between annual rainfall regimes, sediment supply, sediment composition, relative wetland size to catchment area and wetland geomorphic character. To test the hypothesis that the suspended sediments and associated total phosphorus were retained by the adjacent floodplain system and to determine which parts of the two floodplains were most effective for retaining suspended sediments and phosphorus, concurrent measurements of sediment accretion were made at 6 sites in different geomorphic features in each of the floodplains. This was achieved using Cesium-137 and Lead-210 (Hereinafter referred to as ¹³⁷Cs and ²¹⁰Pb) dating techniques. In-field observations suggested that all geomorphic units are still active and are frequently inundated during overbank flood flows. The average overbank sediment deposition and total phosphorus accumulation rates were 9376.9 g-sediment m¯² yr¯¹, 0.8 g-TP m¯² yr¯¹ for the Gatberg floodplain and 11802.8 g-sediment m¯² yr¯¹, 1.0 g-TP m¯² yr¯¹ for the Minnehaha floodplain. Deposition rates were temporally and spatially highly variable and dependent on the sediment supply, microtopographic relief, sinuosity, distance from the channel, the mode of inundation, and the extent of retention pondage. Overall, high average deposition rates were associated closest to the channel within the proximal floodplain zone (9712.1 g-sediment m¯² yr¯¹, 1.0 g-TP m¯² yr¯¹ for the Gatberg floodplain; 13541.1 g-sediment m¯² yr¯¹, 1.0 g-TP m¯² yr¯¹ for the Minnehaha floodplain) where the highest D₅₀ particle sizes (25.4 μm for the Gatberg and 32.8 μm for the Minnehaha) and percentage sand fractions (15 % and 21 %, respectively) were found. This may reflect the coarse nature of the sediment and the frequent connectivity to the channel, suggesting rapid accumulation is linked to a larger particle size which was deposited more readily in this zone. In the Gatberg system, the backswamp zone had one of the highest sedimentation rates and second highest phosphorus accumulation rates (13806.8 g-sediment m¯² yr¯¹, 0.9 g-TP m¯² yr¯¹). This was attributed to the additional coarse sediment inputs from the uncapped gravel forestry road that runs adjacent to the floodplain margin. In contrast, the backswamp zone within the Minnehaha River floodplain system had the lowest sedimentation rates (2005.9 g-sediment m¯² yr¯¹, 0.1 g-TP m¯² yr¯¹, which is what would be expected for the zone furthest away from the channel. In both floodplains, oxbows were important fine-sediment and phosphorus retention features (7126.0 g-sediment m¯² yr¯¹, 0.6 g-TP m¯² yr¯¹ for the Gatberg floodplain; 10101.0 g-sediment m¯² yr¯¹, 1.1 g-TP m¯² yr¯¹). Phosphorus distribution patterns were mainly attributed to variations in organic matter content and iron concentrations in fine-grained sediment deposits, while particle size distributions were less important. Using a mass balance approach the trapping efficiencies of the two floodplain systems were estimated. The average trapping efficiency for the Gatberg River floodplain accounts for 16 % of the suspended sediment yield (1317.5 tonnes-sediment yr¯¹) and 8 % of the suspended sediment-associated total phosphorus yield (0.093 tonnes-TP yr¯¹). Deposition on the Minnehaha floodplain accounts for an average of 44 % (1073.6 tonnes-sediment yr¯¹) and 49 % of the suspended sediment-associated total phosphorus yield (0.098 tonnes-TP yr¯¹). Within the Gatberg and Minnehaha River floodplain systems, the sediment sinks (oxbow and backswamp geomorphic zones) accounted for 13 % and 6 % (1070.6 tonnes-sediment yr¯¹ and 0.069 tonnes-TP yr¯¹); and 28 % and 33 % (683.2 tonnes-sediment yr¯¹ and 0.066 tonnes-TP yr¯¹), respectively, of the mean proportion of the total sediment and associated phosphorus yield. The zone of potential exchange (the proximal floodplain geomorphic zone) within the Gatberg floodplain system was calculated to trap 3 % (247.1 tonnes-yr¯¹) of the mean proportion of the total sediment yield and 2 % (0.023-tonnes yr¯¹) of the mean proportion of the total associated-phosphorus yield. Within the Minnehaha floodplain, this zone was estimated to trap 16 % (390.4 tonnes-sediment yr¯¹ and 0.032 tonnes-TP yr¯¹) of the mean proportion of both the total sediment and associated total phosphorus yield. These results indicate the importance of the distal floodplain reaches and oxbows as sediment and phosphorus storage hotspots. While floodplains mainly result from the accumulation of sediment, they're often modified and altered by erosion processes. Channel erosion and avulsions (e.g. meander bend cutoff events) are natural dynamic processes and form two of the principal processes of meandering river migration. During two wet seasons, both Gatberg and Minnehaha River floodplain areas experienced a mix of deposition and erosion, with slightly higher erosion observed in the Gatberg River reach. Channel bed scouring was prevalent in most cross-sections, suggesting limited sediment accumulation within the main channel beds. Volumetric estimates of sediment loss from meander migration were calculated by analysing cross-sectional data from 2019 and 2021 surveys to determine median and maximum eroded volumes, which were then converted to mass and scaled to tonnes per year for each river's eroded meander bends. The eroded sediment volumes were estimated as 520 tonnes yr¯¹ for the Gatberg and 360 tonnes yr¯¹ for the Minnehaha. The time sequence analysis using historical aerial images (between 1958, 1966, 1993, and 2015) revealed a few channel planform changes due to meander bend cutoff events in both river reaches. These events influence river morphology, increasing local channel slope, reducing sinuosity, and limiting floodplain access while impacting sediment and phosphorus flux. In the Gatberg system, changes in land use, such as increased road density from commercial forestry activities, likely drove channel straightening to accommodate higher sediment and bed loads. In the Minnehaha system, agricultural practices and livestock tracks likely increased sediment loads and hillslope-channel connectivity, driving channel changes. The results from the geochronology of two nested oxbows on the Gatberg floodplain estimated lateral migration rates of ~0.03 m yr¯¹. The floodplain reworking rates of the Gatberg River floodplain are low compared to other systems in humid regions around the world, although, the Gatberg system compares well with migration rates of rivers in dryland regions. This study highlights the potential for floodplains undergoing regular flooding to be effective natural buffers along the sediment and phosphorus cascade in dryland landscapes. It enhances our comprehension of how sediment accumulates over time on floodplains within South African river systems, shedding light on both spatial and temporal patterns. These insights can contribute to better methodologies for evaluating the services provided by floodplain wetlands. These results can inform management decisions by offering a deeper understanding and allowing for the quantification of the cost-benefit of floodplain restoration and preservation actions in South Africa. , Thesis (PhD) -- Faculty of Science, Faculty of Science, Geography, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Schlegel, Philippa Kirsten
- Date: 2024-10-11
- Subjects: Sediments (Geology) , Phosphorus , Sedimentation and deposition , Ecosystem services Law and legislation South Africa , Arid regions South Africa
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466860 , vital:76793 , DOI https://doi.org/10.21504/10962/466860
- Description: A key function of floodplain wetlands systems is their ability to remove and store sediments and associated particulates (such as nutrients, organic carbon, and contaminants) from water, thus improving water quality for downstream ecosystems and water users. Increases in sediment and nutrient inputs to drainage networks pose a serious challenge to integrated resource management. These issues can be partly mitigated through natural buffering solutions along drainage networks, such as preserving essential wetland systems like floodplains. However, their trapping efficiency and storage timescales are uncertain. Although a large body of international knowledge and literature has advanced our understanding of river-floodplain systems and the ecosystem services that they provide, the factors determining their likelihood and effectiveness in supplying those regulatory ecosystem services have not been extensively and scientifically tested in floodplain systems in South Africa. This research aimed to describe and quantify the regulatory ecosystem services related to sediment and phosphorus buffering dynamics of two meandering floodplain systems in the Eastern Cape, South Africa. The study examined the geomorphology, sedimentology, and historical rates of sediment and associated phosphorus accumulation and release in the two floodplain systems. These systems varied in their morphometric features, size, catchment location, and predominant land use, providing a diverse range of characteristics. A comparative analysis was conducted between the two systems to understand the influence of local and catchment-scale factors. Time-averaged suspended sediment samples from the two wetlands were used to compare suspended sediment and associated total phosphorous fluxes over annual scales. Although both floodplains were net depositional during the study period, contemporary suspended sediment mass balance calculations suggested that the relatively larger Minnehaha floodplain system (~1.5 km²) situated in a significantly smaller catchment (~40 km²) had notably higher sediment and associated phosphorus trapping efficiencies of 44 % and 49 % respectively, compared to 16 % and 8 % for the relatively small Gatberg floodplain system (~0.3 km2) situated in a much larger catchment (~135 km²). This variability is attributed to the interaction between annual rainfall regimes, sediment supply, sediment composition, relative wetland size to catchment area and wetland geomorphic character. To test the hypothesis that the suspended sediments and associated total phosphorus were retained by the adjacent floodplain system and to determine which parts of the two floodplains were most effective for retaining suspended sediments and phosphorus, concurrent measurements of sediment accretion were made at 6 sites in different geomorphic features in each of the floodplains. This was achieved using Cesium-137 and Lead-210 (Hereinafter referred to as ¹³⁷Cs and ²¹⁰Pb) dating techniques. In-field observations suggested that all geomorphic units are still active and are frequently inundated during overbank flood flows. The average overbank sediment deposition and total phosphorus accumulation rates were 9376.9 g-sediment m¯² yr¯¹, 0.8 g-TP m¯² yr¯¹ for the Gatberg floodplain and 11802.8 g-sediment m¯² yr¯¹, 1.0 g-TP m¯² yr¯¹ for the Minnehaha floodplain. Deposition rates were temporally and spatially highly variable and dependent on the sediment supply, microtopographic relief, sinuosity, distance from the channel, the mode of inundation, and the extent of retention pondage. Overall, high average deposition rates were associated closest to the channel within the proximal floodplain zone (9712.1 g-sediment m¯² yr¯¹, 1.0 g-TP m¯² yr¯¹ for the Gatberg floodplain; 13541.1 g-sediment m¯² yr¯¹, 1.0 g-TP m¯² yr¯¹ for the Minnehaha floodplain) where the highest D₅₀ particle sizes (25.4 μm for the Gatberg and 32.8 μm for the Minnehaha) and percentage sand fractions (15 % and 21 %, respectively) were found. This may reflect the coarse nature of the sediment and the frequent connectivity to the channel, suggesting rapid accumulation is linked to a larger particle size which was deposited more readily in this zone. In the Gatberg system, the backswamp zone had one of the highest sedimentation rates and second highest phosphorus accumulation rates (13806.8 g-sediment m¯² yr¯¹, 0.9 g-TP m¯² yr¯¹). This was attributed to the additional coarse sediment inputs from the uncapped gravel forestry road that runs adjacent to the floodplain margin. In contrast, the backswamp zone within the Minnehaha River floodplain system had the lowest sedimentation rates (2005.9 g-sediment m¯² yr¯¹, 0.1 g-TP m¯² yr¯¹, which is what would be expected for the zone furthest away from the channel. In both floodplains, oxbows were important fine-sediment and phosphorus retention features (7126.0 g-sediment m¯² yr¯¹, 0.6 g-TP m¯² yr¯¹ for the Gatberg floodplain; 10101.0 g-sediment m¯² yr¯¹, 1.1 g-TP m¯² yr¯¹). Phosphorus distribution patterns were mainly attributed to variations in organic matter content and iron concentrations in fine-grained sediment deposits, while particle size distributions were less important. Using a mass balance approach the trapping efficiencies of the two floodplain systems were estimated. The average trapping efficiency for the Gatberg River floodplain accounts for 16 % of the suspended sediment yield (1317.5 tonnes-sediment yr¯¹) and 8 % of the suspended sediment-associated total phosphorus yield (0.093 tonnes-TP yr¯¹). Deposition on the Minnehaha floodplain accounts for an average of 44 % (1073.6 tonnes-sediment yr¯¹) and 49 % of the suspended sediment-associated total phosphorus yield (0.098 tonnes-TP yr¯¹). Within the Gatberg and Minnehaha River floodplain systems, the sediment sinks (oxbow and backswamp geomorphic zones) accounted for 13 % and 6 % (1070.6 tonnes-sediment yr¯¹ and 0.069 tonnes-TP yr¯¹); and 28 % and 33 % (683.2 tonnes-sediment yr¯¹ and 0.066 tonnes-TP yr¯¹), respectively, of the mean proportion of the total sediment and associated phosphorus yield. The zone of potential exchange (the proximal floodplain geomorphic zone) within the Gatberg floodplain system was calculated to trap 3 % (247.1 tonnes-yr¯¹) of the mean proportion of the total sediment yield and 2 % (0.023-tonnes yr¯¹) of the mean proportion of the total associated-phosphorus yield. Within the Minnehaha floodplain, this zone was estimated to trap 16 % (390.4 tonnes-sediment yr¯¹ and 0.032 tonnes-TP yr¯¹) of the mean proportion of both the total sediment and associated total phosphorus yield. These results indicate the importance of the distal floodplain reaches and oxbows as sediment and phosphorus storage hotspots. While floodplains mainly result from the accumulation of sediment, they're often modified and altered by erosion processes. Channel erosion and avulsions (e.g. meander bend cutoff events) are natural dynamic processes and form two of the principal processes of meandering river migration. During two wet seasons, both Gatberg and Minnehaha River floodplain areas experienced a mix of deposition and erosion, with slightly higher erosion observed in the Gatberg River reach. Channel bed scouring was prevalent in most cross-sections, suggesting limited sediment accumulation within the main channel beds. Volumetric estimates of sediment loss from meander migration were calculated by analysing cross-sectional data from 2019 and 2021 surveys to determine median and maximum eroded volumes, which were then converted to mass and scaled to tonnes per year for each river's eroded meander bends. The eroded sediment volumes were estimated as 520 tonnes yr¯¹ for the Gatberg and 360 tonnes yr¯¹ for the Minnehaha. The time sequence analysis using historical aerial images (between 1958, 1966, 1993, and 2015) revealed a few channel planform changes due to meander bend cutoff events in both river reaches. These events influence river morphology, increasing local channel slope, reducing sinuosity, and limiting floodplain access while impacting sediment and phosphorus flux. In the Gatberg system, changes in land use, such as increased road density from commercial forestry activities, likely drove channel straightening to accommodate higher sediment and bed loads. In the Minnehaha system, agricultural practices and livestock tracks likely increased sediment loads and hillslope-channel connectivity, driving channel changes. The results from the geochronology of two nested oxbows on the Gatberg floodplain estimated lateral migration rates of ~0.03 m yr¯¹. The floodplain reworking rates of the Gatberg River floodplain are low compared to other systems in humid regions around the world, although, the Gatberg system compares well with migration rates of rivers in dryland regions. This study highlights the potential for floodplains undergoing regular flooding to be effective natural buffers along the sediment and phosphorus cascade in dryland landscapes. It enhances our comprehension of how sediment accumulates over time on floodplains within South African river systems, shedding light on both spatial and temporal patterns. These insights can contribute to better methodologies for evaluating the services provided by floodplain wetlands. These results can inform management decisions by offering a deeper understanding and allowing for the quantification of the cost-benefit of floodplain restoration and preservation actions in South Africa. , Thesis (PhD) -- Faculty of Science, Faculty of Science, Geography, 2024
- Full Text:
- Date Issued: 2024-10-11
Selective and sensitive electrochemical detection of the Human Epidermal Growth Receptor 2 breast cancer biomarker, using Co (II) phthalocyanine-nanoparticle based platforms
- Centane, Sixolile Sibongiseni
- Authors: Centane, Sixolile Sibongiseni
- Date: 2024-10-11
- Subjects: Electrochemical sensors , HER-2 protein , Breast Cancer , Biochemical markers , Phthalocyanines , Nanoparticles
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466569 , vital:76753 , DOI https://doi.org/10.21504/10962/466570
- Description: Breast cancer is the world’s leading cause of cancer related deaths in women worldwide. The main reason lies in its late detection, mostly in the metastatic stage resulting in poor after-therapy prognosis, despite advances in methods of diagnosis and therapy. The reason for late-stage detection, is because breast cancer like any other cancers is asymptomatic in its early stages. Significant and characterizable features present in the later stages. Furthermore, conventional methods for breast cancer detection are more useful in the identification of the phenotypic features of cancer cells that arise at a later stage of the disease. Another issue with conventional methods where cancer diagnosis is concerned is that they tend to be specialist-dependent, time consuming and costly. Thus, easy, fast and inexpensive detection methods need to be developed urgently. Biomarker-based cancer diagnosis has emerged as one of the most promising strategies for early diagnosis, monitoring disease progression, and subsequent cancer treatment. This thesis focuses on the design and development of novel electrochemical biosensor platforms towards the low cost, efficient, sensitive and simple detection of early-stage breast cancer biomarker, human epidermal growth factor 2 (HER2). The electrochemical method is preferred because of its moderate cost, rapid response, ease of operation, readily quantifiable signal as well as high sensitivity and selectivity with lower detection limits. This thesis reports on two strategies towards signal amplification and sensitive detection of HER2, namely signal based amplification and target-based amplification. The former focuses on electrode or transducer modification techniques for improved signal to noise ratio. In which case; novel nanocomposites of phthalocyanines, graphene quantum dots, gold nanoparticles and cerium oxide nanoparticles are used for electrode modification for signal amplification and biorecognition element immobilization. The biorecognition elements of choice, are an aptamer and antibody known to be specific to the HER2 antigen for an enhanced sensor sensitivity and specificity. The second strategy focuses on increasing the number of detectable targets on the electrode surface towards enhanced sensitivity, precision and sensor accuracy. In which case; the performance of the aptamer and the antibody as recognition elements was explored. Furthermore, the effect of arrangement of these recognition elements on the electrode surface is investigated and reported upon. The strategies covered in this thesis are expected to result in novel biosensor platforms that can detect the HER2 biomarker with high precision, reproducibility, sensitivity and stability; towards low cost and effective early-stage breast cancer diagnostic tools. , Thesis (PhD) -- Faculty of Science, Chemistry, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Centane, Sixolile Sibongiseni
- Date: 2024-10-11
- Subjects: Electrochemical sensors , HER-2 protein , Breast Cancer , Biochemical markers , Phthalocyanines , Nanoparticles
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466569 , vital:76753 , DOI https://doi.org/10.21504/10962/466570
- Description: Breast cancer is the world’s leading cause of cancer related deaths in women worldwide. The main reason lies in its late detection, mostly in the metastatic stage resulting in poor after-therapy prognosis, despite advances in methods of diagnosis and therapy. The reason for late-stage detection, is because breast cancer like any other cancers is asymptomatic in its early stages. Significant and characterizable features present in the later stages. Furthermore, conventional methods for breast cancer detection are more useful in the identification of the phenotypic features of cancer cells that arise at a later stage of the disease. Another issue with conventional methods where cancer diagnosis is concerned is that they tend to be specialist-dependent, time consuming and costly. Thus, easy, fast and inexpensive detection methods need to be developed urgently. Biomarker-based cancer diagnosis has emerged as one of the most promising strategies for early diagnosis, monitoring disease progression, and subsequent cancer treatment. This thesis focuses on the design and development of novel electrochemical biosensor platforms towards the low cost, efficient, sensitive and simple detection of early-stage breast cancer biomarker, human epidermal growth factor 2 (HER2). The electrochemical method is preferred because of its moderate cost, rapid response, ease of operation, readily quantifiable signal as well as high sensitivity and selectivity with lower detection limits. This thesis reports on two strategies towards signal amplification and sensitive detection of HER2, namely signal based amplification and target-based amplification. The former focuses on electrode or transducer modification techniques for improved signal to noise ratio. In which case; novel nanocomposites of phthalocyanines, graphene quantum dots, gold nanoparticles and cerium oxide nanoparticles are used for electrode modification for signal amplification and biorecognition element immobilization. The biorecognition elements of choice, are an aptamer and antibody known to be specific to the HER2 antigen for an enhanced sensor sensitivity and specificity. The second strategy focuses on increasing the number of detectable targets on the electrode surface towards enhanced sensitivity, precision and sensor accuracy. In which case; the performance of the aptamer and the antibody as recognition elements was explored. Furthermore, the effect of arrangement of these recognition elements on the electrode surface is investigated and reported upon. The strategies covered in this thesis are expected to result in novel biosensor platforms that can detect the HER2 biomarker with high precision, reproducibility, sensitivity and stability; towards low cost and effective early-stage breast cancer diagnostic tools. , Thesis (PhD) -- Faculty of Science, Chemistry, 2024
- Full Text:
- Date Issued: 2024-10-11
Shaping self through ceramic sculpture: representing anxiety in the rural black queer experience
- Authors: Phaliso, Phila Vuyiseka
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/466082 , vital:76683
- Description: I am a ceramic sculptor. I make use of clay that I have sourced from Joza, the Makhanda location, and Cofimvaba in a rural area called Magwala. I process this clay and then use it to create a visual and tangible representation of the anxiety I experience as a queer black woman living in South Africa. Unongayindoda is a word that has been used by isiXhosa speaking people in my village to call me ever since I was a child. This is a word that I have chosen to own, in much the same way that some people have chosen to own the word “queer.” My experience of being unongayindoda has had an impact on my mental health, and the process of digging clay, processing it for use and then using it to create my work has become very therapeutic for me. My work’s primary aim is to explore the use of clay as a representative embodiment of anxiety in my work as a rural black queer sculptor who identifies as unongayindoda. The thesis component of my work is a qualitative study informed by autoethnography, practice and art-based research. , Thesis (MA) -- Faculty of Humanities, Fine Art, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Phaliso, Phila Vuyiseka
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/466082 , vital:76683
- Description: I am a ceramic sculptor. I make use of clay that I have sourced from Joza, the Makhanda location, and Cofimvaba in a rural area called Magwala. I process this clay and then use it to create a visual and tangible representation of the anxiety I experience as a queer black woman living in South Africa. Unongayindoda is a word that has been used by isiXhosa speaking people in my village to call me ever since I was a child. This is a word that I have chosen to own, in much the same way that some people have chosen to own the word “queer.” My experience of being unongayindoda has had an impact on my mental health, and the process of digging clay, processing it for use and then using it to create my work has become very therapeutic for me. My work’s primary aim is to explore the use of clay as a representative embodiment of anxiety in my work as a rural black queer sculptor who identifies as unongayindoda. The thesis component of my work is a qualitative study informed by autoethnography, practice and art-based research. , Thesis (MA) -- Faculty of Humanities, Fine Art, 2024
- Full Text:
- Date Issued: 2024-10-11