Production, purification, and characterisation of proteases from an ericoid mycorrhizal fungus, Oidiodendron maius
- Authors: Manyumwa, Colleen Varaidzo
- Date: 2018
- Subjects: Ascomycetes , Mycorrhizal fungi , Ericaceae , Proteolytic enzymes , Silver Recycling
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/62833 , vital:28298
- Description: The aim of this study was to produce, purify and characterise proteases from the ericoid mycorrhizal fungus, Oidiodendron maius (CafRU082b/KP119480), as well as to explore their potential application in the recovery of silver from X-ray film. Firstly, the growth of the ericoid mycorrhizal fungus, Oidiodendron maius (CafRU082b), was studied, and its ability to produce proteolytic enzymes was investigated. O. maius proved to grow well in the dark, submerged in Modified Melin Norkran’s liquid medium at a pH of 5 and at 25°C. Pure cultures of the fungus were maintained on Potato Dextrose Agar (PDA). The fungus grew on PDA plates containing different substrates including haemoglobin, casein, gelatin as well as azocasein. Zones of clearance, however, were only observed on plates containing gelatin after treatment with mercuric chloride, HgCl2. Proteases were successfully produced after 14 days when gelatin was incorporated into the growth medium. After production of the proteases, purification and characterisation of the enzymes was performed. Purification of the enzymes was performed by acetone precipitation followed by ultrafiltration with 50 kDa and 30 kDa cut off membrane filters. A final purification fold of approximately 37.6 was achieved. Unusual yields of above 100% were observed after each purification step with the final yield achieved being 196% with a final specific activity of 2707 U/mg. SDS-PAGE revealed a protease band of 35 kDa which was also visible on the zymogram at approximately 36 kDa. The zymogram showed clear hydrolysis bands against a blue background after staining with Coomassie Brilliant Blue. Physico-chemical characterisation of the protease revealed its pH optimum to be pH 3.0 and its temperature optimum 68°C. Another peak was observed on the pH profile at pH 7.0. The protease exhibited high thermostability at temperatures 37°C, 80°C as well as 100°C with the enzyme retaining close to 50% of its initial activity after 4 h of exposure to all three temperatures. All ions tested for their effects on the proteases, except Ca2+, enhanced protease activity. Ca2+ did not exhibit any significant effect on the enzyme’s activity while Zn2+ had the highest effect, enhancing enzyme activity by 305%. The proteases, however, were not significantly inhibited by EDTA, a metal chelating agent and a known metalloprotease inhibitor. The enzyme was classified as an aspartic protease due to complete inhibition by 25 μM of pepstatin A, coupled to its low pH optimum of 3.0. Addition of trans-Epoxysuccinyl-L-leucylamido-(4-guanidino)butane (E-64), a cysteine protease inhibitor, and 2-mercaptoethanol increased protease activity. The proteases exhibited a narrow substrate specificity towards gelatin and no other substrate. Substrate kinetics values were plotted on a Michaelis-Menten Graph and showed that the enzyme had a Vmax of 55.25 U/ml and a Km of 2.7 mg/ml gelatin. A low Km indicated that the protease had a high affinity for gelatin. Silver recovery studies from X-ray film revealed the proteases’ capability to remove silver from X-ray film, leaving the film intact. The recovery of silver was perceived visually, by film observation, as well as by scan electron microscopy (SEM) images, where clearance of the film was observed after incubation with the enzyme. Energy dispersive X-ray spectroscopy (EDS) profiles also confirmed removal of silver from the film, with a Ag peak showing on the profile of the film before treatment with the proteases and no peak after treatment. The crude protease sample was, however, catalytically more efficient compared to the partially purified sample. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2018
- Full Text:
- Date Issued: 2018
- Authors: Manyumwa, Colleen Varaidzo
- Date: 2018
- Subjects: Ascomycetes , Mycorrhizal fungi , Ericaceae , Proteolytic enzymes , Silver Recycling
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/62833 , vital:28298
- Description: The aim of this study was to produce, purify and characterise proteases from the ericoid mycorrhizal fungus, Oidiodendron maius (CafRU082b/KP119480), as well as to explore their potential application in the recovery of silver from X-ray film. Firstly, the growth of the ericoid mycorrhizal fungus, Oidiodendron maius (CafRU082b), was studied, and its ability to produce proteolytic enzymes was investigated. O. maius proved to grow well in the dark, submerged in Modified Melin Norkran’s liquid medium at a pH of 5 and at 25°C. Pure cultures of the fungus were maintained on Potato Dextrose Agar (PDA). The fungus grew on PDA plates containing different substrates including haemoglobin, casein, gelatin as well as azocasein. Zones of clearance, however, were only observed on plates containing gelatin after treatment with mercuric chloride, HgCl2. Proteases were successfully produced after 14 days when gelatin was incorporated into the growth medium. After production of the proteases, purification and characterisation of the enzymes was performed. Purification of the enzymes was performed by acetone precipitation followed by ultrafiltration with 50 kDa and 30 kDa cut off membrane filters. A final purification fold of approximately 37.6 was achieved. Unusual yields of above 100% were observed after each purification step with the final yield achieved being 196% with a final specific activity of 2707 U/mg. SDS-PAGE revealed a protease band of 35 kDa which was also visible on the zymogram at approximately 36 kDa. The zymogram showed clear hydrolysis bands against a blue background after staining with Coomassie Brilliant Blue. Physico-chemical characterisation of the protease revealed its pH optimum to be pH 3.0 and its temperature optimum 68°C. Another peak was observed on the pH profile at pH 7.0. The protease exhibited high thermostability at temperatures 37°C, 80°C as well as 100°C with the enzyme retaining close to 50% of its initial activity after 4 h of exposure to all three temperatures. All ions tested for their effects on the proteases, except Ca2+, enhanced protease activity. Ca2+ did not exhibit any significant effect on the enzyme’s activity while Zn2+ had the highest effect, enhancing enzyme activity by 305%. The proteases, however, were not significantly inhibited by EDTA, a metal chelating agent and a known metalloprotease inhibitor. The enzyme was classified as an aspartic protease due to complete inhibition by 25 μM of pepstatin A, coupled to its low pH optimum of 3.0. Addition of trans-Epoxysuccinyl-L-leucylamido-(4-guanidino)butane (E-64), a cysteine protease inhibitor, and 2-mercaptoethanol increased protease activity. The proteases exhibited a narrow substrate specificity towards gelatin and no other substrate. Substrate kinetics values were plotted on a Michaelis-Menten Graph and showed that the enzyme had a Vmax of 55.25 U/ml and a Km of 2.7 mg/ml gelatin. A low Km indicated that the protease had a high affinity for gelatin. Silver recovery studies from X-ray film revealed the proteases’ capability to remove silver from X-ray film, leaving the film intact. The recovery of silver was perceived visually, by film observation, as well as by scan electron microscopy (SEM) images, where clearance of the film was observed after incubation with the enzyme. Energy dispersive X-ray spectroscopy (EDS) profiles also confirmed removal of silver from the film, with a Ag peak showing on the profile of the film before treatment with the proteases and no peak after treatment. The crude protease sample was, however, catalytically more efficient compared to the partially purified sample. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2018
- Full Text:
- Date Issued: 2018
Exploring para-thiophenols to expand the SAR of antimalarial 3-indolylethanones
- Authors: Chisango, Ruramai Lissa
- Date: 2018
- Subjects: Antimalarials , Malaria Chemotherapy , Thiols , Plasmodium falciparum , Blood-brain barrier
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/63515 , vital:28428
- Description: According to the WHO, malaria is responsible for over half a million deaths annually especially in populations from disadvantaged settings. Although there has been a documented improvement in the mortality rates, malaria has proved to be a global emergency. Mostly affecting the poor population, this disease is perpetuating a vicious cycle of poverty in the developing world as current preventive measures are not adequate unless adopted in addition to effective treatment. However, there has been a worldwide increase in resistance to available treatment which presents a need for novel, affordable treatment. A study conducted in our laboratory identified two hit thiophenol containing compounds 2.24 and 2.25. These molecules provided initial insight into the SAR and potential pharmacophore of this class of compounds. We decided to further explore these compounds by making bioisosteric replacements to optimize the structure as we monitor the effect of these modifications on the anti-plasmodial activity. The synthetic pathway to form the target compounds of our study comprised of three steps which were initiated by the Friedel-Crafts acetylation of the indoles resulting in compounds 3.5 - 3.7. A bromination step followed which yielded the -bromo ketones (3.8 - 3.11). Some of the thiophenols (3.14 and 3.16) were not readily available in our laboratory and so were synthesized for the final synthetic step. This step involved the nucleophilic displacement of the -bromine to generate the -aryl substituted 3-indolylethanones (3.17 - 3.27). The thioethers displayed improved antimalarial activity from 2.24 and 2.25 against the chloroquine sensitive 3D7 Plasmodium falciparum strain. In addition, these compounds were non-toxic against HeLa cells which indicated this potential novel class of antimalarials is selective for the malaria parasite as hypothesized in the previous study conducted in our laboratory. In an attempt to predict the bioavailability of some of our compounds, in silico studies were conducted revealing that these compounds could be passively absorbed by the gastrointestinal tract, a positive result for bioavailability purposes. However, results from these studies indicate that modifications of these compounds would be necessary to allow for permeation through the blood brain barrier (BBB) for instances when the patient has cerebral malaria. , Thesis (MSc) -- Faculty of Pharmacy, Pharmacy, 2018
- Full Text:
- Date Issued: 2018
- Authors: Chisango, Ruramai Lissa
- Date: 2018
- Subjects: Antimalarials , Malaria Chemotherapy , Thiols , Plasmodium falciparum , Blood-brain barrier
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/63515 , vital:28428
- Description: According to the WHO, malaria is responsible for over half a million deaths annually especially in populations from disadvantaged settings. Although there has been a documented improvement in the mortality rates, malaria has proved to be a global emergency. Mostly affecting the poor population, this disease is perpetuating a vicious cycle of poverty in the developing world as current preventive measures are not adequate unless adopted in addition to effective treatment. However, there has been a worldwide increase in resistance to available treatment which presents a need for novel, affordable treatment. A study conducted in our laboratory identified two hit thiophenol containing compounds 2.24 and 2.25. These molecules provided initial insight into the SAR and potential pharmacophore of this class of compounds. We decided to further explore these compounds by making bioisosteric replacements to optimize the structure as we monitor the effect of these modifications on the anti-plasmodial activity. The synthetic pathway to form the target compounds of our study comprised of three steps which were initiated by the Friedel-Crafts acetylation of the indoles resulting in compounds 3.5 - 3.7. A bromination step followed which yielded the -bromo ketones (3.8 - 3.11). Some of the thiophenols (3.14 and 3.16) were not readily available in our laboratory and so were synthesized for the final synthetic step. This step involved the nucleophilic displacement of the -bromine to generate the -aryl substituted 3-indolylethanones (3.17 - 3.27). The thioethers displayed improved antimalarial activity from 2.24 and 2.25 against the chloroquine sensitive 3D7 Plasmodium falciparum strain. In addition, these compounds were non-toxic against HeLa cells which indicated this potential novel class of antimalarials is selective for the malaria parasite as hypothesized in the previous study conducted in our laboratory. In an attempt to predict the bioavailability of some of our compounds, in silico studies were conducted revealing that these compounds could be passively absorbed by the gastrointestinal tract, a positive result for bioavailability purposes. However, results from these studies indicate that modifications of these compounds would be necessary to allow for permeation through the blood brain barrier (BBB) for instances when the patient has cerebral malaria. , Thesis (MSc) -- Faculty of Pharmacy, Pharmacy, 2018
- Full Text:
- Date Issued: 2018
An investigation into the bacterial communities associated with pyrroloiminoquinone-producing South African latrunculid sponges
- Authors: Hilliar, Storm Hannah
- Date: 2018
- Subjects: Sponges South Africa Algoa Bay , Betaproteobacteria , Spirochaeta , Symbiosis , Bacterial communities
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/62112 , vital:28128
- Description: Marine sponges belonging to the family Latrunculiidae are known for their production of cytotoxic pyrroloiminoquinone alkaloids and the South African coast provides a unique environment for the exploitation of these potent bioactive compounds. The isolation of structurally similar pyrroloiminoquinone compounds from unrelated, non poriferan sources has led to the suggestion that South African latrunculid pyrroloiminoquinones may be secondary metabolites produced by sponge associated microbial symbionts. Previous studies investigating the bacterial communities of South African latrunculid sponges have shown the conservation of distinct microbial populations with unusual bacterial taxa dominated by a novel betaproteobacterial and spirochete species. This study describes the further investigation into these associated bacterial communities, their conservation and sponge microbiome comparisons across spatial, temporal and environmental scales. The bacterial communities associated with seven latrunculid species representing three genera (Tsitsikamma, Cyclacanthia and Latrunculia) were characterized as well as a Mycale and Tethya rubra species. Latrunculid sponge microbiomes were significantly different from those associated with sympatric outlier sponge species and the surrounding environment. The bacterial communities associated with latrunculid sponges appear host specific with the conservation of two dominant bacterial symbionts which mirror the phylogeny of their host species. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2018
- Full Text:
- Date Issued: 2018
- Authors: Hilliar, Storm Hannah
- Date: 2018
- Subjects: Sponges South Africa Algoa Bay , Betaproteobacteria , Spirochaeta , Symbiosis , Bacterial communities
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/62112 , vital:28128
- Description: Marine sponges belonging to the family Latrunculiidae are known for their production of cytotoxic pyrroloiminoquinone alkaloids and the South African coast provides a unique environment for the exploitation of these potent bioactive compounds. The isolation of structurally similar pyrroloiminoquinone compounds from unrelated, non poriferan sources has led to the suggestion that South African latrunculid pyrroloiminoquinones may be secondary metabolites produced by sponge associated microbial symbionts. Previous studies investigating the bacterial communities of South African latrunculid sponges have shown the conservation of distinct microbial populations with unusual bacterial taxa dominated by a novel betaproteobacterial and spirochete species. This study describes the further investigation into these associated bacterial communities, their conservation and sponge microbiome comparisons across spatial, temporal and environmental scales. The bacterial communities associated with seven latrunculid species representing three genera (Tsitsikamma, Cyclacanthia and Latrunculia) were characterized as well as a Mycale and Tethya rubra species. Latrunculid sponge microbiomes were significantly different from those associated with sympatric outlier sponge species and the surrounding environment. The bacterial communities associated with latrunculid sponges appear host specific with the conservation of two dominant bacterial symbionts which mirror the phylogeny of their host species. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2018
- Full Text:
- Date Issued: 2018
Evaluation of Megabruchidius tonkineus (Coleoptera: Chrysomelidae: Bruchinae), a candidate biological control agent for Gleditsia triacanthos L. (Fabaceae) in South Africa
- Salgado Astudillo, Sara Elizabeth
- Authors: Salgado Astudillo, Sara Elizabeth
- Date: 2021-10
- Subjects: Honey locust South Africa , Honey locust Biological control South Africa , Invasive plants Biological control South Africa , Biogeography South Africa , Biogeography Climatic factors South Africa , Megabruchidius tonkineus South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/188386 , vital:44749
- Description: Gleditsia triacanthos L. (Fabaceae) (honey locust) is a fast-growing, deciduous tree indigenous to the United States of America. Introduced around the world as an ornamental tree, it has become invasive in a number of countries. Where it is invasive, G. triacanthos competes and replaces indigenous species; it creates dense stands along watercourses, posing a significant environmental threat. In South Africa, G. triacanthos is regarded as one of the country’s fastest spreading weeds. Gleditsia triacanthos produces numerous seeds contained in large hanging pods. Once dislodged from the pods, the seeds are dispersed by birds and mammals, including livestock, which eat the pods. It has been suggested that the seeds should be the target for biological control programme. Some invasive alien plant species are characterised by their ability to spread and establish in new ecosystems because they tolerate a wide range of environmental conditions. In order to predict areas of likely invasion, species distribution models (SDMs) are used to identify areas climatically suitable for their invasion, so enabling better targeted control of the plant species. Gleditsia triacanthos adapts to a wide range of climates and soil types, and tolerates salinity, drought and frost. Currently primarily restricted to the Grassland Biome of South Africa, G. triacanthos has doubled its distribution area in the past 15 years, and it is not known how far the species will spread. In this study we used two different modelling programmes, CLIMEX and MaxEnt, to predict areas where G. triacanthos could find favourable growing conditions; both SDMs showed that most of the country is suitable for G. triacanthos and that it will probably continue to spread, if left unmanaged, into new bioregions, such as the Karoo. In South Africa, the Asian seed-feeding bruchid, Megabruchidius tonkineus (Pic, 1914) (Coleoptera: Chrysomelidae: Bruchinae) has been recorded in the plant’s seed pods and has been considered as a biological control agent. The insect was not released as part of a formal biological control programme and neither host-specificity nor impact studies were conducted on the species prior to its discovery. In 2017 a decision was made to re-consider its status as a Abstract biological control agent until further details of its biology, host specificity, and impact on the seeds of G. triacanthos in South Africa were available. This study shows that Megabruchidius tonkineus has established across the entire G. triacanthos population in South Africa damaging approximately 9% of seeds. Laboratory studies show that, Megabruchidius tonkineus completes its larval development in the seeds of G. triacanthos in about 66.80 ± 0.6880 SE days before eclosing. In addition, the adult females oviposit on the following Fabaceae species: Arachis hypogaea, Albizia, julibrissin, Cicer arietinum, Pisum sativum, Dipogon lignosus, Peltophorum africanum, Podalyria buxifolia Senegalia burkei, Umtiza listerina and Vachellia sieberiana. However, larval development was limited to G. triacanthos. It is concluded that the seed-feeding beetle is not a threat to native Fabaceae species in South Africa, however, it does not damage enough G. triacanthos seeds to be considered a valuable biological control agent at this stage, and additional seed-feeding biological control agents should be considered to reduce the number of G. triacanthos seeds entering the environment. , Thesis (MSc) -- Faculty of Science, Zoology and Entomology, 2021
- Full Text:
- Date Issued: 2021-10
- Authors: Salgado Astudillo, Sara Elizabeth
- Date: 2021-10
- Subjects: Honey locust South Africa , Honey locust Biological control South Africa , Invasive plants Biological control South Africa , Biogeography South Africa , Biogeography Climatic factors South Africa , Megabruchidius tonkineus South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/188386 , vital:44749
- Description: Gleditsia triacanthos L. (Fabaceae) (honey locust) is a fast-growing, deciduous tree indigenous to the United States of America. Introduced around the world as an ornamental tree, it has become invasive in a number of countries. Where it is invasive, G. triacanthos competes and replaces indigenous species; it creates dense stands along watercourses, posing a significant environmental threat. In South Africa, G. triacanthos is regarded as one of the country’s fastest spreading weeds. Gleditsia triacanthos produces numerous seeds contained in large hanging pods. Once dislodged from the pods, the seeds are dispersed by birds and mammals, including livestock, which eat the pods. It has been suggested that the seeds should be the target for biological control programme. Some invasive alien plant species are characterised by their ability to spread and establish in new ecosystems because they tolerate a wide range of environmental conditions. In order to predict areas of likely invasion, species distribution models (SDMs) are used to identify areas climatically suitable for their invasion, so enabling better targeted control of the plant species. Gleditsia triacanthos adapts to a wide range of climates and soil types, and tolerates salinity, drought and frost. Currently primarily restricted to the Grassland Biome of South Africa, G. triacanthos has doubled its distribution area in the past 15 years, and it is not known how far the species will spread. In this study we used two different modelling programmes, CLIMEX and MaxEnt, to predict areas where G. triacanthos could find favourable growing conditions; both SDMs showed that most of the country is suitable for G. triacanthos and that it will probably continue to spread, if left unmanaged, into new bioregions, such as the Karoo. In South Africa, the Asian seed-feeding bruchid, Megabruchidius tonkineus (Pic, 1914) (Coleoptera: Chrysomelidae: Bruchinae) has been recorded in the plant’s seed pods and has been considered as a biological control agent. The insect was not released as part of a formal biological control programme and neither host-specificity nor impact studies were conducted on the species prior to its discovery. In 2017 a decision was made to re-consider its status as a Abstract biological control agent until further details of its biology, host specificity, and impact on the seeds of G. triacanthos in South Africa were available. This study shows that Megabruchidius tonkineus has established across the entire G. triacanthos population in South Africa damaging approximately 9% of seeds. Laboratory studies show that, Megabruchidius tonkineus completes its larval development in the seeds of G. triacanthos in about 66.80 ± 0.6880 SE days before eclosing. In addition, the adult females oviposit on the following Fabaceae species: Arachis hypogaea, Albizia, julibrissin, Cicer arietinum, Pisum sativum, Dipogon lignosus, Peltophorum africanum, Podalyria buxifolia Senegalia burkei, Umtiza listerina and Vachellia sieberiana. However, larval development was limited to G. triacanthos. It is concluded that the seed-feeding beetle is not a threat to native Fabaceae species in South Africa, however, it does not damage enough G. triacanthos seeds to be considered a valuable biological control agent at this stage, and additional seed-feeding biological control agents should be considered to reduce the number of G. triacanthos seeds entering the environment. , Thesis (MSc) -- Faculty of Science, Zoology and Entomology, 2021
- Full Text:
- Date Issued: 2021-10
Development of a 3D bioprinting and standalone bioreactor unit for the production and maintenance of bioscaffolds in vitro
- Authors: Hundling, Jethro Daniel
- Date: 2021-10-29
- Subjects: Bioreactors , Tissue scaffolds , Cell culture , Polyethylene glycol Biotechnology , 3D bioprinting , Poly(ethylene glycol) diacrylate (PEGDA)
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192063 , vital:45192
- Description: The most common method for in vitro cell culture currently is to grow a specific cell type in isolation, in monolayer format, adhered to a 2D culture surface. This brings about many limitations in comparison to in vivo models due to altered cell phenotypes, as caused by the culturing technique itself, and the lack of naturally occurring cell-to-cell interactions. Three dimensional mammalian cell culture technologies have the potential to overcome these limitations, and provide models more representative of natural systems. Unfortunately, the cost and difficulty associated with achieving sustainable and useful 3D mammalian cell culture is still very high, preventing its widespread adoption across scientific platforms. In this research, we investigate the feasibility of developing and producing a visible light-based 3D stereolithographic bioprinter to produce 3D scaffolds for cell culture. Furthermore, we investigate the possibility of developing and implementing a forced perfusion bioreactor system, which would support the produced scaffold and improve longer-term culture conditions. The developed 3D bioprinter, and bioreactor designs were developed and tested alongside Poly (ethylene glycol) diacrylate (PEGDA), a versatile synthetic scaffold material. PEGDA itself was also evaluated for its printability, robustness in culture conditions over time, and its ability to maintain 3D mammalian cell culture. This research showed that both the developed 3D bioprinter, and bioreactor unit were capable of producing and maintaining an easily modifiable PEGDA scaffold, in culture conditions. In addition, the PEGDA formulation developed was shown to allow for the effective and reproducible 3D cell culture conditions over the medium term, with automated media feeding. The research presented here aimed to illustrate a proof of concept that the low-cost development and production of 3D culture scaffold production and maintenance systems was feasible to the scientific research environment. This technology can then be built upon, into a system that would then allow for the broader adoption and investigation of 3D cell culture as a tool within the scientific community. , Thesis (MSc) -- Faculty of Science, Biotechnology Innovation Centre, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Hundling, Jethro Daniel
- Date: 2021-10-29
- Subjects: Bioreactors , Tissue scaffolds , Cell culture , Polyethylene glycol Biotechnology , 3D bioprinting , Poly(ethylene glycol) diacrylate (PEGDA)
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192063 , vital:45192
- Description: The most common method for in vitro cell culture currently is to grow a specific cell type in isolation, in monolayer format, adhered to a 2D culture surface. This brings about many limitations in comparison to in vivo models due to altered cell phenotypes, as caused by the culturing technique itself, and the lack of naturally occurring cell-to-cell interactions. Three dimensional mammalian cell culture technologies have the potential to overcome these limitations, and provide models more representative of natural systems. Unfortunately, the cost and difficulty associated with achieving sustainable and useful 3D mammalian cell culture is still very high, preventing its widespread adoption across scientific platforms. In this research, we investigate the feasibility of developing and producing a visible light-based 3D stereolithographic bioprinter to produce 3D scaffolds for cell culture. Furthermore, we investigate the possibility of developing and implementing a forced perfusion bioreactor system, which would support the produced scaffold and improve longer-term culture conditions. The developed 3D bioprinter, and bioreactor designs were developed and tested alongside Poly (ethylene glycol) diacrylate (PEGDA), a versatile synthetic scaffold material. PEGDA itself was also evaluated for its printability, robustness in culture conditions over time, and its ability to maintain 3D mammalian cell culture. This research showed that both the developed 3D bioprinter, and bioreactor unit were capable of producing and maintaining an easily modifiable PEGDA scaffold, in culture conditions. In addition, the PEGDA formulation developed was shown to allow for the effective and reproducible 3D cell culture conditions over the medium term, with automated media feeding. The research presented here aimed to illustrate a proof of concept that the low-cost development and production of 3D culture scaffold production and maintenance systems was feasible to the scientific research environment. This technology can then be built upon, into a system that would then allow for the broader adoption and investigation of 3D cell culture as a tool within the scientific community. , Thesis (MSc) -- Faculty of Science, Biotechnology Innovation Centre, 2021
- Full Text:
- Date Issued: 2021-10-29
The effect of orchard sanitation and predatory ants on the eclosion of the internal feeding pests and Oriental fruit fly, in South Africa
- Authors: Makitla, Tshepang
- Date: 2022-10-14
- Subjects: Orchards South Africa , Phytosanitation , Citrus Diseases and pests Biological control , Ants , Insects as biological pest control agents
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/362927 , vital:65375
- Description: There are several pests of phytosanitary concern in the citrus industry in South Africa. Orchard sanitation can play an important role in suppressing the populations of these pests, however there are little data on the efficacy of sanitation techniques. Therefore, the current study investigated the effect of fruit disposal techniques and burying depths on the eclosion of the most important pests of citrus in South Africa, false codling moth Thaumatotibia leucotreta Meyrick (Lepidoptera: Tortricidae), Mediterranean fruit fly or Medfly Ceratitis capitata Wiedemann (Diptera: Tephritidae), Natal fruit fly Ceratitis rosa Karsh (Diptera: Tephritidae), and Oriental fruit fly Bactrocera dorsalis Hendel (Diptera: Tephritidae). Abscised C. sinensis fruits were inoculated with larvae of T. leucotreta, and eggs of C. capitata, C. rosa, and B. dorsalis, before being disposed as pulped, or whole, and buried at different depths (0 cm, 5 cm, 25 cm, and 50 cm). Abundance and richness of predatory ants were monitored using pitfall traps to ascertain their effect on the mortality of the immature stages of these pests. Ceratitis capitata and C. rosa failed to eclose from the inoculated fruits disposed at different depths, however, T. leucotreta and B. dorsalis adults did eclosed. Significantly fewer B. dorsalis eclosed from fruits that were pulped in comparison to eclosion where the fruit were left whole (F (3, 16) = 11.45, P < 0.01). Furthermore, depth of burial had a significant effect on the number of eclosed adults of Drosophila sp (F (3, 112) = 3.43, P < 0.01). Burying fruits at 50 cm suppressed the eclosion of all the internal feeding pests tested. Twenty-seven thousand seventy-three individual ants (Hymenoptera: Formicidae) were sampled from the same plots as used above, with at least 47% and 53% sampled from plots where pulped and whole C. sinensis fruits were disposed of, respectively. The ants were identified to morphospecies which included Pheidole1, Pheidole2, Formicinae1, Formicinae2, Formicinae3, and Myrmicinae1. The disposal of the inoculated C. sinensis fruits either as pulped or whole and burying at different depths significantly suppressed and/or delayed the eclosion of either of the tested internal feeding pests of citrus. Although, predacious ants were sampled from the same treatment plots they did not affect the survival or eclosion of the tested pests, and this could be attributed to the application of the slow toxic ant bait. Therefore, based on the observed results B. dorsalis adults showed the ability to eclose from 50 cm depth where fruit was either disposed as pulped or whole, thus, citrus farmers are advised to use hammer mill that will finely crush sanitised fruit, and/or bury fruit beyond 50 cm depth to prevent the adult od this pest from eclosing. , Thesis (MSc) -- Faculty of Science, Zoology and Entomology, 2022
- Full Text:
- Date Issued: 2022-10-14
- Authors: Makitla, Tshepang
- Date: 2022-10-14
- Subjects: Orchards South Africa , Phytosanitation , Citrus Diseases and pests Biological control , Ants , Insects as biological pest control agents
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/362927 , vital:65375
- Description: There are several pests of phytosanitary concern in the citrus industry in South Africa. Orchard sanitation can play an important role in suppressing the populations of these pests, however there are little data on the efficacy of sanitation techniques. Therefore, the current study investigated the effect of fruit disposal techniques and burying depths on the eclosion of the most important pests of citrus in South Africa, false codling moth Thaumatotibia leucotreta Meyrick (Lepidoptera: Tortricidae), Mediterranean fruit fly or Medfly Ceratitis capitata Wiedemann (Diptera: Tephritidae), Natal fruit fly Ceratitis rosa Karsh (Diptera: Tephritidae), and Oriental fruit fly Bactrocera dorsalis Hendel (Diptera: Tephritidae). Abscised C. sinensis fruits were inoculated with larvae of T. leucotreta, and eggs of C. capitata, C. rosa, and B. dorsalis, before being disposed as pulped, or whole, and buried at different depths (0 cm, 5 cm, 25 cm, and 50 cm). Abundance and richness of predatory ants were monitored using pitfall traps to ascertain their effect on the mortality of the immature stages of these pests. Ceratitis capitata and C. rosa failed to eclose from the inoculated fruits disposed at different depths, however, T. leucotreta and B. dorsalis adults did eclosed. Significantly fewer B. dorsalis eclosed from fruits that were pulped in comparison to eclosion where the fruit were left whole (F (3, 16) = 11.45, P < 0.01). Furthermore, depth of burial had a significant effect on the number of eclosed adults of Drosophila sp (F (3, 112) = 3.43, P < 0.01). Burying fruits at 50 cm suppressed the eclosion of all the internal feeding pests tested. Twenty-seven thousand seventy-three individual ants (Hymenoptera: Formicidae) were sampled from the same plots as used above, with at least 47% and 53% sampled from plots where pulped and whole C. sinensis fruits were disposed of, respectively. The ants were identified to morphospecies which included Pheidole1, Pheidole2, Formicinae1, Formicinae2, Formicinae3, and Myrmicinae1. The disposal of the inoculated C. sinensis fruits either as pulped or whole and burying at different depths significantly suppressed and/or delayed the eclosion of either of the tested internal feeding pests of citrus. Although, predacious ants were sampled from the same treatment plots they did not affect the survival or eclosion of the tested pests, and this could be attributed to the application of the slow toxic ant bait. Therefore, based on the observed results B. dorsalis adults showed the ability to eclose from 50 cm depth where fruit was either disposed as pulped or whole, thus, citrus farmers are advised to use hammer mill that will finely crush sanitised fruit, and/or bury fruit beyond 50 cm depth to prevent the adult od this pest from eclosing. , Thesis (MSc) -- Faculty of Science, Zoology and Entomology, 2022
- Full Text:
- Date Issued: 2022-10-14
Formulation, development and assessment of efavirenz-loaded lipid nanocarriers
- Authors: Makoni, Pedzisai Anotida
- Date: 2014
- Subjects: Nanomedicine , Drug delivery systems , Antiretroviral agents Psychotropic effects , AIDS dementia complex
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/209981 , vital:47448
- Description: The feasibility of incorporating efavirenz (EFV) into innovative solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) using the hot high-pressure homogenization (HHPH) technique was investigated in an attempt to address the shortcomings in therapy associated with the use of conventional dosage forms. The shortcomings include the unpalatable taste of API in solution, instability in the presence of light when in solution and psychiatric side effects of the API. In particular, sustained release approaches may reduce or limit the incidence of adverse psychiatric effects of EFV and alleviate Acquired Immune Deficiency Syndrome (AIDS)-related complications such as AIDS Dementia Complex (ADC) in patients, ultimately improving their quality of life. Prior to initiating pre-formulation, formulation development and optimization studies of EFV-loaded SLN and/or NLC, Response Surface Methodology (RSM) in conjunction with central composite design (CCD), was used to develop and validate suitable methods for the quantitative determination of EFV in pharmaceutical formulations and for monitoring EFV release from SLN and/or NLC in vitro. Simple, accurate, precise, sensitive and stabilityindicating reversed phase-high performance liquid chromatography (RP-HPLC) methods with UV and electrochemical (EC) detection were developed, validated and optimized for in vitro analysis of EFV in formulations. On the basis of risk-to-benefit ratio the RP-HPLC method with UV detection was selected as the most suitable for the quantitative determination of EFV in pharmaceutical formulations, and was applied to in vitro release studies of EFV from SLN and/or NLC. Pre-formulation studies were undertaken to investigate the thermal stability of EFV so as to facilitate the selection of lipid excipients for the manufacture of nanocarriers, and to establish their compatibility with EFV. It was found that EFV was thermostable up to a temperature of approximately 200°C, indicating that HHPH could be used for the manufacture of EFV-loaded SLN and/or NLC. Lipid screening revealed that EFV is highly soluble in solid and liquid lipids, with glyceryl monostearate and Transcutol® HP showing the best solubilizing potential for EFV. Glyceryl monostearate exists in a stable β-modification prior to exposure to heat, but exists in the α-polymorphic modification following exposure to heat. It was established that the addition of Transcutol® HP to glyceryl monostearate revealed the co-existence of the α- and β’-polymorphic modifications, thereby revealing the existence of the modifications in NLC produced from the optimum lipid combination. Furthermore, an investigation of binary mixtures of EFV/glyceryl monostearate and glyceryl monostearate/Transcutol® HP, in addition to eutectic mixtures of EFV, glyceryl monostearate and Transcutol® HP, revealed no interaction between EFV and the lipids selected for the production of the nanocarriers. Due to the significantly higher solubility of EFV in Transcutol® HP than in to glyceryl monostearate, NLC are most likely to have a higher LC and EE than SLN. In addition, the existence of both the α- and β’-polymorphic modifications in the binary mixture of the lipid implies that EFV expulsion on prolonged storage is unlikely to occur from NLC when compared to SLN. Consequently formulation development and optimization studies of SLN and NLC were performed to investigate the potential to deliver EFV from a novel technology with an appropriate LC and EE for EFV. Tween®80 was selected for use in these formulations as the use of this surfactant facilitates the targeting of nanocarriers to the CNS. RSM in conjunction with a Box-Behnken Design (BBD) was used to establish the effects of process variables, such as number of homogenization cycles and pressure, in addition to formulation variables such as amount of EFV and Tween®80 on the particle size (PS), polydispersity index (PDI), zeta potential (ZP), visual assessment (VA) and release rate (RR) of EFV after 24 hours. In addition the LC and EE, degree of crystallinity and lipid modification, shape and surface morphology of the optimized batches were investigated to ensure that EFV-loaded SLN and NLC of desirable quality were produced. On the day of manufacture the mean PS and PDI of EFV-loaded SLN was 59.00 ± 23.16 nm and 0.382 ± 0.054 respectively. The mean PS and PDI of EFV-loaded NLC was 34.73 ± 0.7709 nm and 0.394 ± 0.027 respectively. The formulations were in the nanometer range and exhibited a narrow particle size distribution, as indicated by the PDI values. The ZP values for optimized SLN and NLC generated on the day of manufacture using HPLC grade water as the dispersion medium were -32.5 ± 4.99 mV and -22.4 ± 3.72 mV respectively. In addition the optimized batches of SLN and NLC revealed a decrease in crystallinity in comparison to bulk lipid material. DSC, WAXS and FT-IR revealed that EFV was molecularly dispersed in the nanocarriers. In addition EFV-loaded SLN existed in a single α-polymorphic form, whereas EFV-loaded NLC exhibited the co-existence of α- and β’-polymorphic forms. Generally SLN and NLC were spherically shaped when viewed under transmission electron microscopy (TEM) and scanning electron microscopy (SEM). On the day of manufacture the EE and LC of EFVloaded SLN was found to be 96.77 ± 0.453 % and 9.68 ± 1.772 % respectively. The EE and LC of EFV-loaded NLC was 99.93 ± 0.413 and 9.995 ± 0.672 respectively. The release profiles for the optimized formulations of SLN and NLC exhibited an initial burst release over the first 0-3 hours of testing, after which the release was sustained for up to 24 hours. The cumulative % EFV released over 24 hours was higher from SLN (91.5±3.423 %) than that observed for NLC (73.6±4.34 %). Stability studies performed for 8 weeks on the optimized batches of the SLN and the NLC were also conducted so as to ensure product quality. The formulations were assessed in terms of parameters considered benchmarks of stability, and included ZP, PS, PDI, LC and EE. Generally these parameters remained unchanged following storage for 8 weeks at 25°C/60% RH but showed considerable changes following storage for 8 weeks at 40°C/75% RH. These studies reveal that SLN and NLC when stored at 25°C/60% RH have the potential to be used as colloidal delivery systems for EFV that have the potential to protect EFV from photodegradation and sustain release into brain tissue. The latter will ultimately reduce or limit the incidence of adverse psychiatric effects and potentially alleviate AIDS-related complications such as ADC in patients with HIV/AIDS, ultimately improving their quality of life. , Thesis (MSc) -- Faculty of Pharmacy, Pharmacy, 2014
- Full Text:
- Date Issued: 2014
- Authors: Makoni, Pedzisai Anotida
- Date: 2014
- Subjects: Nanomedicine , Drug delivery systems , Antiretroviral agents Psychotropic effects , AIDS dementia complex
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/209981 , vital:47448
- Description: The feasibility of incorporating efavirenz (EFV) into innovative solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) using the hot high-pressure homogenization (HHPH) technique was investigated in an attempt to address the shortcomings in therapy associated with the use of conventional dosage forms. The shortcomings include the unpalatable taste of API in solution, instability in the presence of light when in solution and psychiatric side effects of the API. In particular, sustained release approaches may reduce or limit the incidence of adverse psychiatric effects of EFV and alleviate Acquired Immune Deficiency Syndrome (AIDS)-related complications such as AIDS Dementia Complex (ADC) in patients, ultimately improving their quality of life. Prior to initiating pre-formulation, formulation development and optimization studies of EFV-loaded SLN and/or NLC, Response Surface Methodology (RSM) in conjunction with central composite design (CCD), was used to develop and validate suitable methods for the quantitative determination of EFV in pharmaceutical formulations and for monitoring EFV release from SLN and/or NLC in vitro. Simple, accurate, precise, sensitive and stabilityindicating reversed phase-high performance liquid chromatography (RP-HPLC) methods with UV and electrochemical (EC) detection were developed, validated and optimized for in vitro analysis of EFV in formulations. On the basis of risk-to-benefit ratio the RP-HPLC method with UV detection was selected as the most suitable for the quantitative determination of EFV in pharmaceutical formulations, and was applied to in vitro release studies of EFV from SLN and/or NLC. Pre-formulation studies were undertaken to investigate the thermal stability of EFV so as to facilitate the selection of lipid excipients for the manufacture of nanocarriers, and to establish their compatibility with EFV. It was found that EFV was thermostable up to a temperature of approximately 200°C, indicating that HHPH could be used for the manufacture of EFV-loaded SLN and/or NLC. Lipid screening revealed that EFV is highly soluble in solid and liquid lipids, with glyceryl monostearate and Transcutol® HP showing the best solubilizing potential for EFV. Glyceryl monostearate exists in a stable β-modification prior to exposure to heat, but exists in the α-polymorphic modification following exposure to heat. It was established that the addition of Transcutol® HP to glyceryl monostearate revealed the co-existence of the α- and β’-polymorphic modifications, thereby revealing the existence of the modifications in NLC produced from the optimum lipid combination. Furthermore, an investigation of binary mixtures of EFV/glyceryl monostearate and glyceryl monostearate/Transcutol® HP, in addition to eutectic mixtures of EFV, glyceryl monostearate and Transcutol® HP, revealed no interaction between EFV and the lipids selected for the production of the nanocarriers. Due to the significantly higher solubility of EFV in Transcutol® HP than in to glyceryl monostearate, NLC are most likely to have a higher LC and EE than SLN. In addition, the existence of both the α- and β’-polymorphic modifications in the binary mixture of the lipid implies that EFV expulsion on prolonged storage is unlikely to occur from NLC when compared to SLN. Consequently formulation development and optimization studies of SLN and NLC were performed to investigate the potential to deliver EFV from a novel technology with an appropriate LC and EE for EFV. Tween®80 was selected for use in these formulations as the use of this surfactant facilitates the targeting of nanocarriers to the CNS. RSM in conjunction with a Box-Behnken Design (BBD) was used to establish the effects of process variables, such as number of homogenization cycles and pressure, in addition to formulation variables such as amount of EFV and Tween®80 on the particle size (PS), polydispersity index (PDI), zeta potential (ZP), visual assessment (VA) and release rate (RR) of EFV after 24 hours. In addition the LC and EE, degree of crystallinity and lipid modification, shape and surface morphology of the optimized batches were investigated to ensure that EFV-loaded SLN and NLC of desirable quality were produced. On the day of manufacture the mean PS and PDI of EFV-loaded SLN was 59.00 ± 23.16 nm and 0.382 ± 0.054 respectively. The mean PS and PDI of EFV-loaded NLC was 34.73 ± 0.7709 nm and 0.394 ± 0.027 respectively. The formulations were in the nanometer range and exhibited a narrow particle size distribution, as indicated by the PDI values. The ZP values for optimized SLN and NLC generated on the day of manufacture using HPLC grade water as the dispersion medium were -32.5 ± 4.99 mV and -22.4 ± 3.72 mV respectively. In addition the optimized batches of SLN and NLC revealed a decrease in crystallinity in comparison to bulk lipid material. DSC, WAXS and FT-IR revealed that EFV was molecularly dispersed in the nanocarriers. In addition EFV-loaded SLN existed in a single α-polymorphic form, whereas EFV-loaded NLC exhibited the co-existence of α- and β’-polymorphic forms. Generally SLN and NLC were spherically shaped when viewed under transmission electron microscopy (TEM) and scanning electron microscopy (SEM). On the day of manufacture the EE and LC of EFVloaded SLN was found to be 96.77 ± 0.453 % and 9.68 ± 1.772 % respectively. The EE and LC of EFV-loaded NLC was 99.93 ± 0.413 and 9.995 ± 0.672 respectively. The release profiles for the optimized formulations of SLN and NLC exhibited an initial burst release over the first 0-3 hours of testing, after which the release was sustained for up to 24 hours. The cumulative % EFV released over 24 hours was higher from SLN (91.5±3.423 %) than that observed for NLC (73.6±4.34 %). Stability studies performed for 8 weeks on the optimized batches of the SLN and the NLC were also conducted so as to ensure product quality. The formulations were assessed in terms of parameters considered benchmarks of stability, and included ZP, PS, PDI, LC and EE. Generally these parameters remained unchanged following storage for 8 weeks at 25°C/60% RH but showed considerable changes following storage for 8 weeks at 40°C/75% RH. These studies reveal that SLN and NLC when stored at 25°C/60% RH have the potential to be used as colloidal delivery systems for EFV that have the potential to protect EFV from photodegradation and sustain release into brain tissue. The latter will ultimately reduce or limit the incidence of adverse psychiatric effects and potentially alleviate AIDS-related complications such as ADC in patients with HIV/AIDS, ultimately improving their quality of life. , Thesis (MSc) -- Faculty of Pharmacy, Pharmacy, 2014
- Full Text:
- Date Issued: 2014
The Kinetic-Tree-House-Person drawing test as a diagnostic instrument in assessment of sexually abused children and monitoring the effects of group play therapy
- Authors: Donaldson, Marilyn Ann
- Date: 1993
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/193140 , vital:45302
- Description: This research project was developed from the idea that children's drawings reflect both their internal emotional lives and their external lived worlds. The subjects of the project were sexually abused children referred to Fort England Hospital during the first half of 1992. The Kinetic-Tree-House-Person projective drawing test was used as an instrument of assessment in conjunction with the Maudsley Child Psychiatric interview technique. Indications of the effects of sexual abuse were sought in drawing tests administered before and after interventions of ten sessions of group play therapy. Drawing tests were also administered to a control group of children. The research project explored the effectiveness of group play therapy interventions through comparison of pre intervention and post intervention drawings. The rationale for this project was the high incidence of rape and sexual abuse of prepubescent black young women in the Eastern Cape particularly, and in South Africa generally. There is need for both assessments of screening instruments and validation of therapeutic interventions if this problem is to be addressed adequately. , Thesis (MA) -- Faculty of Humanities, Psychology, 1993
- Full Text:
- Date Issued: 1993
- Authors: Donaldson, Marilyn Ann
- Date: 1993
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/193140 , vital:45302
- Description: This research project was developed from the idea that children's drawings reflect both their internal emotional lives and their external lived worlds. The subjects of the project were sexually abused children referred to Fort England Hospital during the first half of 1992. The Kinetic-Tree-House-Person projective drawing test was used as an instrument of assessment in conjunction with the Maudsley Child Psychiatric interview technique. Indications of the effects of sexual abuse were sought in drawing tests administered before and after interventions of ten sessions of group play therapy. Drawing tests were also administered to a control group of children. The research project explored the effectiveness of group play therapy interventions through comparison of pre intervention and post intervention drawings. The rationale for this project was the high incidence of rape and sexual abuse of prepubescent black young women in the Eastern Cape particularly, and in South Africa generally. There is need for both assessments of screening instruments and validation of therapeutic interventions if this problem is to be addressed adequately. , Thesis (MA) -- Faculty of Humanities, Psychology, 1993
- Full Text:
- Date Issued: 1993
Chipangano: vigilantism and community responses in Mbare District, Zimbabwe, c.2000-2013
- Authors: Munyarari, Tinashe
- Date: 2018
- Subjects: Vigilantism Zimbabwe Mbare , ZANU-PF (Organization : Zimbabwe) , Zimbabwe History 1980- , Vigilantism Zimbabwe Mbare Public opinion , Collective memory Zimbabwe Mbare
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/62126 , vital:28130
- Description: This study examines an aspect of Zimbabwe’s political history, namely the emergence and operations of Chipangano vigilante group in Mbare (2000-2013) and how the community responded to the scourges of this vigilante group. This study shows that Chipangano, which means a pact, was formed with the intention to extend ZANU-PF patronage system, canvassing support and regain control of Mbare district from the MDC. The group consolidated itself as a shadow militia group for ZANU-PF that intimidated the opposition parties and coerced the general populace to attend ZANU-PF functions. It also shows that the vigilante group seized Harare City Council’s duties, such as collecting gate-takings from local and long distance public transport at Mbare Bus Terminal; controlling allocations of market stalls and collecting rents from market stalls, for personal benefits. The group also politicised the access to local state property. Chipangano’s collusion with ZANU-PF and state structures licensed it to engage in criminal activities with impunity, thus this thesis seeks to understand the relationship between the vigilantes, ZANU-PF and state structures. The activities of Chipangano such as abduction, intimidation, beatings, killings and displacement of people resulted in social trauma. This thesis will also explore how this phase of violence is remembered today by the research informants. , Thesis (MA) -- Faculty of Humanities, History, 2018
- Full Text:
- Date Issued: 2018
- Authors: Munyarari, Tinashe
- Date: 2018
- Subjects: Vigilantism Zimbabwe Mbare , ZANU-PF (Organization : Zimbabwe) , Zimbabwe History 1980- , Vigilantism Zimbabwe Mbare Public opinion , Collective memory Zimbabwe Mbare
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/62126 , vital:28130
- Description: This study examines an aspect of Zimbabwe’s political history, namely the emergence and operations of Chipangano vigilante group in Mbare (2000-2013) and how the community responded to the scourges of this vigilante group. This study shows that Chipangano, which means a pact, was formed with the intention to extend ZANU-PF patronage system, canvassing support and regain control of Mbare district from the MDC. The group consolidated itself as a shadow militia group for ZANU-PF that intimidated the opposition parties and coerced the general populace to attend ZANU-PF functions. It also shows that the vigilante group seized Harare City Council’s duties, such as collecting gate-takings from local and long distance public transport at Mbare Bus Terminal; controlling allocations of market stalls and collecting rents from market stalls, for personal benefits. The group also politicised the access to local state property. Chipangano’s collusion with ZANU-PF and state structures licensed it to engage in criminal activities with impunity, thus this thesis seeks to understand the relationship between the vigilantes, ZANU-PF and state structures. The activities of Chipangano such as abduction, intimidation, beatings, killings and displacement of people resulted in social trauma. This thesis will also explore how this phase of violence is remembered today by the research informants. , Thesis (MA) -- Faculty of Humanities, History, 2018
- Full Text:
- Date Issued: 2018
Investigating cannabinoids and endocannabinoid receptors as drug targets for pain and inflammation
- Authors: Marwarwa, Sinobomi Zamachi
- Date: 2020
- Subjects: Cannabinoids , Cannabinoids Receptors , Inflammation Alternative treatment , Pain Alternative treatment , Drug targeting
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/164468 , vital:41121
- Description: Cannabinoids and the endocannabinoid system have been studied in the past decades but have yet to be fully understood. An insight into interactions that occur between cannabinoid compounds and their receptors is important for understanding the cannabinoids and the endocannabinoid system. Cannabinoids are natural products found in some cannabis plants, and they have similar effects to endocannabinoids, which are chemicals in the body that are involved many aspects of health from appetite, memory, and movement to pain, inflammation and response to cancer. Cannabinoids have a high impact on the treatment of pain and inflammation, they show different antinociceptive mechanisms to existing drugs like opioids, also, they have antimigraine properties better than those achieved by aspirin. The CB1 and CB2 human receptors have been the most studied cannabinoid receptors. In this project, we used a combination of mass-spectrometry to generate plausible chemical fragments and computational techniques to assess the binding of these fragments to these two main CB receptors. CB1 was adapted from the protein data bank (PBD), file 5U09 and the CB2 model was predicted using the hierarchical protocol I-TASSER, starting from the amino acid sequence in UniProt (P34972 CNR2_HUMAN). The proposed active site for CB1 was reported in a publication accompanying the 5U09 PDB model, which was originally generated with a pre-existing ligand in the active site. However, CB2 had to be built from a homology model and the active site determined using a combination of I-TASSER, Maestro, and CASTp the more favourable binding energies were determined by CASTp, leading to the use of the CASTp coordinates as default for docking in the CB2 human receptor. The molecular docking of cannabinoids THC, CBD, CBDV, CBG and CBN on both the CB1 and CB2 proteins was performed to identify the amino acids that interact with these compounds at their active sites. This would provide a guide to a future fragment-based drug discovery (FBDD) synthesis project. The docking in this work showed adequate accuracy with binding energies between -8.23 kcal/mol and -9.97 kcal/mol for CB1 and between -6.78 kcal/mol and -7.74 kcal/mol for CB2. An observation made was that binding energies of the CB1 human receptor docking were higher than those of the CB2 human receptor, which could support the widely held belief that CB1 is more important in cannabinoid interactions. The cannabinoids were then subjected to collision-induced dissociation to produce fragment structures predicted in chapter 2. These hypothetical fragments were docked in the CB1 and CB2 human receptor, the general trend again being the binding energies for the CB1 receptor was again around 10% higher than those of the CB2 receptor. As expected, larger fragments tended to have better binding, with the fragment proposed from m/z 259 with binding energies -9.62 kcal/mol in CB1 and -6.26 kcal/mol. Those fragments with significant lipophilic side chains or some aromatic moiety also showed good binding or around -6.00 kcal/mol, similar to the intact cannabinoids. In our case, this fragment was proposed from m/z 223 with binding energies -7.71 kcal/mol in CB1 and -6.5 kcal/mol in CB2. The results from the fragment dockings were favourable in that they have binding affinities lower than -6.0 kcal/mol which is good enough for the structures to be leads in the creation of fragment libraries. The docking was performed with Autodock 1.5.6 and data visualization with a discovery studio. , Thesis (MSc) -- Faculty of Science, Chemistry, 2020
- Full Text:
- Date Issued: 2020
- Authors: Marwarwa, Sinobomi Zamachi
- Date: 2020
- Subjects: Cannabinoids , Cannabinoids Receptors , Inflammation Alternative treatment , Pain Alternative treatment , Drug targeting
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/164468 , vital:41121
- Description: Cannabinoids and the endocannabinoid system have been studied in the past decades but have yet to be fully understood. An insight into interactions that occur between cannabinoid compounds and their receptors is important for understanding the cannabinoids and the endocannabinoid system. Cannabinoids are natural products found in some cannabis plants, and they have similar effects to endocannabinoids, which are chemicals in the body that are involved many aspects of health from appetite, memory, and movement to pain, inflammation and response to cancer. Cannabinoids have a high impact on the treatment of pain and inflammation, they show different antinociceptive mechanisms to existing drugs like opioids, also, they have antimigraine properties better than those achieved by aspirin. The CB1 and CB2 human receptors have been the most studied cannabinoid receptors. In this project, we used a combination of mass-spectrometry to generate plausible chemical fragments and computational techniques to assess the binding of these fragments to these two main CB receptors. CB1 was adapted from the protein data bank (PBD), file 5U09 and the CB2 model was predicted using the hierarchical protocol I-TASSER, starting from the amino acid sequence in UniProt (P34972 CNR2_HUMAN). The proposed active site for CB1 was reported in a publication accompanying the 5U09 PDB model, which was originally generated with a pre-existing ligand in the active site. However, CB2 had to be built from a homology model and the active site determined using a combination of I-TASSER, Maestro, and CASTp the more favourable binding energies were determined by CASTp, leading to the use of the CASTp coordinates as default for docking in the CB2 human receptor. The molecular docking of cannabinoids THC, CBD, CBDV, CBG and CBN on both the CB1 and CB2 proteins was performed to identify the amino acids that interact with these compounds at their active sites. This would provide a guide to a future fragment-based drug discovery (FBDD) synthesis project. The docking in this work showed adequate accuracy with binding energies between -8.23 kcal/mol and -9.97 kcal/mol for CB1 and between -6.78 kcal/mol and -7.74 kcal/mol for CB2. An observation made was that binding energies of the CB1 human receptor docking were higher than those of the CB2 human receptor, which could support the widely held belief that CB1 is more important in cannabinoid interactions. The cannabinoids were then subjected to collision-induced dissociation to produce fragment structures predicted in chapter 2. These hypothetical fragments were docked in the CB1 and CB2 human receptor, the general trend again being the binding energies for the CB1 receptor was again around 10% higher than those of the CB2 receptor. As expected, larger fragments tended to have better binding, with the fragment proposed from m/z 259 with binding energies -9.62 kcal/mol in CB1 and -6.26 kcal/mol. Those fragments with significant lipophilic side chains or some aromatic moiety also showed good binding or around -6.00 kcal/mol, similar to the intact cannabinoids. In our case, this fragment was proposed from m/z 223 with binding energies -7.71 kcal/mol in CB1 and -6.5 kcal/mol in CB2. The results from the fragment dockings were favourable in that they have binding affinities lower than -6.0 kcal/mol which is good enough for the structures to be leads in the creation of fragment libraries. The docking was performed with Autodock 1.5.6 and data visualization with a discovery studio. , Thesis (MSc) -- Faculty of Science, Chemistry, 2020
- Full Text:
- Date Issued: 2020
The moderating effect of socioeconomic factors on the relationship between financial inclusion and poverty among South African vulnerable households
- Authors: Khalane, Pontso Violet
- Date: 2023-03-31
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/419451 , vital:71645
- Description: Vulnerable households are often excluded from the formal financial sector, subsequently experiencing more poverty. Vulnerable households are those that face higher chances of experiencing higher levels of poverty due to their socioeconomic factors. This study aimed to determine the moderating effect of socioeconomic factors on the relationship between financial inclusion and poverty among South African vulnerable households. Poverty is the involuntary lack of monetary and other resources that can afford households with basic human needs and a decent standard of living above a chosen poverty measure. This study measured poverty using a multidimensional measure that incorporated a household’s deprivation of health, education and a decent standard of living. Financial inclusion refers to a process of incorporating vulnerable households into the formal financial sector by ensuring that they receive timely and adequate access to regulated financial products at an affordable price, regardless of their socioeconomic status. This study measured financial inclusion multidimensionally using access to four basic regulated financial products. Socioeconomic factors included gender, race, first or home language, age, the highest level and many more factors. This study was supported by theoretical framework of the vulnerable group theory of financial inclusion, financial development theory, the credit rationing theory and the public goods theory of financial inclusion. The study adopted a quantitative research design. The study used existing data from the FinMark FinScope 2016 South Africa database, which collected data on households’ demographics and their ownership of financial products. Using a closed-ended questionnaire, FinMark FinScope collected the data across South Africa through a multi-probability sampling technique. The final database used in this study after data cleaning contained a sample of 2759 households. The study used descriptive statistics, Pearson’s product-moment correlation, ANOVA and Multiple regression to investigate the factors of the study. The results of the study found a statistically significant relationship between financial inclusion and vulnerable households. The results also found a statistically significant relationship between poverty and vulnerable households. The results further showed a statistically significant negative relationship between financial inclusion and poverty. Lastly, the study found that only socioeconomic factors such as marital status, age as it relates to children and old people moderating effect on the relationship between financial inclusion and poverty among South African vulnerable households. Subsequently, it was concluded that vulnerable households experienced higher levels of poverty in South Africa, and these vulnerable households were less financially included in South Africa. Additionally, it was found that increasing vulnerable households’ access to all regulated financial products could help decrease their poverty levels. The study made several recommendations, which included inter-alia that formal financial institutions design products that specifically meet the needs of vulnerable households. This study also recommended that banks play a central role in facilitating vulnerable households’ affordability of health in South Africa (e.g., offering affordable healthcare products to vulnerable households). Theoretically, this study contributed to the body of literature using multidimensional financial inclusion and poverty, as well as determining the moderating effect of socioeconomic factors. Practically, this study provided insights to the banks on how to develop their products to meet the needs of vulnerable households, help alleviate poverty, and increase the banks’ market into previously unbanked or underbanked segments of the population of South Africa. , Thesis (MCom) -- Faculty of Commerce, Accounting, 2023
- Full Text:
- Date Issued: 2023-03-31
- Authors: Khalane, Pontso Violet
- Date: 2023-03-31
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/419451 , vital:71645
- Description: Vulnerable households are often excluded from the formal financial sector, subsequently experiencing more poverty. Vulnerable households are those that face higher chances of experiencing higher levels of poverty due to their socioeconomic factors. This study aimed to determine the moderating effect of socioeconomic factors on the relationship between financial inclusion and poverty among South African vulnerable households. Poverty is the involuntary lack of monetary and other resources that can afford households with basic human needs and a decent standard of living above a chosen poverty measure. This study measured poverty using a multidimensional measure that incorporated a household’s deprivation of health, education and a decent standard of living. Financial inclusion refers to a process of incorporating vulnerable households into the formal financial sector by ensuring that they receive timely and adequate access to regulated financial products at an affordable price, regardless of their socioeconomic status. This study measured financial inclusion multidimensionally using access to four basic regulated financial products. Socioeconomic factors included gender, race, first or home language, age, the highest level and many more factors. This study was supported by theoretical framework of the vulnerable group theory of financial inclusion, financial development theory, the credit rationing theory and the public goods theory of financial inclusion. The study adopted a quantitative research design. The study used existing data from the FinMark FinScope 2016 South Africa database, which collected data on households’ demographics and their ownership of financial products. Using a closed-ended questionnaire, FinMark FinScope collected the data across South Africa through a multi-probability sampling technique. The final database used in this study after data cleaning contained a sample of 2759 households. The study used descriptive statistics, Pearson’s product-moment correlation, ANOVA and Multiple regression to investigate the factors of the study. The results of the study found a statistically significant relationship between financial inclusion and vulnerable households. The results also found a statistically significant relationship between poverty and vulnerable households. The results further showed a statistically significant negative relationship between financial inclusion and poverty. Lastly, the study found that only socioeconomic factors such as marital status, age as it relates to children and old people moderating effect on the relationship between financial inclusion and poverty among South African vulnerable households. Subsequently, it was concluded that vulnerable households experienced higher levels of poverty in South Africa, and these vulnerable households were less financially included in South Africa. Additionally, it was found that increasing vulnerable households’ access to all regulated financial products could help decrease their poverty levels. The study made several recommendations, which included inter-alia that formal financial institutions design products that specifically meet the needs of vulnerable households. This study also recommended that banks play a central role in facilitating vulnerable households’ affordability of health in South Africa (e.g., offering affordable healthcare products to vulnerable households). Theoretically, this study contributed to the body of literature using multidimensional financial inclusion and poverty, as well as determining the moderating effect of socioeconomic factors. Practically, this study provided insights to the banks on how to develop their products to meet the needs of vulnerable households, help alleviate poverty, and increase the banks’ market into previously unbanked or underbanked segments of the population of South Africa. , Thesis (MCom) -- Faculty of Commerce, Accounting, 2023
- Full Text:
- Date Issued: 2023-03-31
Innovation in ecological restoration techniques: Enhancing Portulacaria afra survivorship in degraded arid thicket
- Authors: Norman, Yondela Masande
- Date: 2023-03-31
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/419276 , vital:71630
- Description: The Albany Thicket Biome has undergone extensive degradation over the past century, particularly from overstocking of livestock in the arid types of thicket. The degradation of the biome, coupled with little to no natural recovery, prompted the South African Government to implement the Subtropical Thicket Restoration Programme (STRP) in the early 2000s to rehabilitate degraded thicket using unrooted Portulacaria afra truncheons. The STRP also sought to create job opportunities, bring about social upliftment, promote biodiversity conservation and incentivise farmers and landowners in the region to promote carbon trading and farming of P. afra using carbon credits. However, the survivorship of P. afra planted using the STRP planting protocol has been less than ⁓30% because they are planted in degraded areas, where the truncheons are subjected to harsh biophysical conditions such as hard, capped soil, high soil temperatures, drought and herbivory. The aim of this study, therefore, was to improve the survivorship of P. afra planted in degraded thicket to at least 30%, using modified planting methods. In this study, four treatments were applied in 210 pondings (or micro-dams), each with P. afra planted in them (the first three treatments used rooted cuttings). The first treatment involved watering regimes where pondings were watered at varying frequencies. The second treatment involved planting companion species alongside P. afra while the third treatment involved planting P. afra underneath a nurse canopy. In the fourth treatment, unrooted P. afra truncheons were planted inside pondings. The mean survivorship of the P. afra cuttings was assessed 18 months after planting. The watering regime treatments, including the control, all yielded a survivorship of over 75%, with the significantly highest levels of survivorship being displayed in the weekly watering treatment (90.9 ± 6.8%) (p < 0.01). The companion plant treatment also produced a high mean survivorship of P. afra (94.9 ± 3.6%), significantly higher than that of the nurse plants (87.5 ± 6.3%) (p < 0.01). Among the unrooted truncheons it was found that untreated truncheons had the highest survivorship (76.2 ± 17.6%), with the lowest mean being found in truncheons that were both pruned and scarified (70.8 ± 20.8%), suggesting that this treatment, out of all of them, is the least successful under the prevailing environmental conditions in the study area. However, there was no significant differences among the unrooted truncheon treatments and their respective survivorship values to further substantiate this assertion (p = 0.26). Findings in this study also suggest that planting P. afra cuttings under a nurse plant was ideal for P. afra survivorship due to the nurse plant’s ability to ameliorate the microclimate under which the cuttings can establish and grow. Despite the soil under the nurse canopy having a significantly lower mean soil water potential (-160.9 ± 200.5 kPa), compared to the open areas (-73.4 ± 55.7 kPa) (p = 0.04), the pondings under the nurse canopy still had a lower mean soil temperature (31.4 ± 5.25°C) than the treatments in the open areas (38.5 ± 2.7°C), during the harsh midday sun. These favourable characteristics are reflected in the P. afra cuttings under a nurse canopy having a higher chlorophyll fluorescence (0.76 ± 0.06). compared to those planted in open areas (0.73 ± 0.13), suggesting that the P. afra cuttings in the former treatment had a higher photosynthetic efficiency compared to those in the latter, despite there being no statistically significant difference in chlorophyll fluorescence between the treatments (p = 0.14). Although these findings suggest that applying these modifications to planting P. afra, having achieved its objective of increasing survivorship to well over 50%, is likely to produce favourable results not only in overall survivorship, but also in fast-tracking arid thicket rehabilitation and restoration, further research on these rehabilitation techniques and their effectiveness is required. Furthermore, the downside to these treatments is that they are costly and time consuming, which puts the feasibility of large-scale programmes using these applications into question. Further investigation is required to determine ways in which the cost-effectiveness of these applications can be enhanced. , Thesis (MSc) -- Faculty of Science, Environmental Science, 2023
- Full Text:
- Date Issued: 2023-03-31
- Authors: Norman, Yondela Masande
- Date: 2023-03-31
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/419276 , vital:71630
- Description: The Albany Thicket Biome has undergone extensive degradation over the past century, particularly from overstocking of livestock in the arid types of thicket. The degradation of the biome, coupled with little to no natural recovery, prompted the South African Government to implement the Subtropical Thicket Restoration Programme (STRP) in the early 2000s to rehabilitate degraded thicket using unrooted Portulacaria afra truncheons. The STRP also sought to create job opportunities, bring about social upliftment, promote biodiversity conservation and incentivise farmers and landowners in the region to promote carbon trading and farming of P. afra using carbon credits. However, the survivorship of P. afra planted using the STRP planting protocol has been less than ⁓30% because they are planted in degraded areas, where the truncheons are subjected to harsh biophysical conditions such as hard, capped soil, high soil temperatures, drought and herbivory. The aim of this study, therefore, was to improve the survivorship of P. afra planted in degraded thicket to at least 30%, using modified planting methods. In this study, four treatments were applied in 210 pondings (or micro-dams), each with P. afra planted in them (the first three treatments used rooted cuttings). The first treatment involved watering regimes where pondings were watered at varying frequencies. The second treatment involved planting companion species alongside P. afra while the third treatment involved planting P. afra underneath a nurse canopy. In the fourth treatment, unrooted P. afra truncheons were planted inside pondings. The mean survivorship of the P. afra cuttings was assessed 18 months after planting. The watering regime treatments, including the control, all yielded a survivorship of over 75%, with the significantly highest levels of survivorship being displayed in the weekly watering treatment (90.9 ± 6.8%) (p < 0.01). The companion plant treatment also produced a high mean survivorship of P. afra (94.9 ± 3.6%), significantly higher than that of the nurse plants (87.5 ± 6.3%) (p < 0.01). Among the unrooted truncheons it was found that untreated truncheons had the highest survivorship (76.2 ± 17.6%), with the lowest mean being found in truncheons that were both pruned and scarified (70.8 ± 20.8%), suggesting that this treatment, out of all of them, is the least successful under the prevailing environmental conditions in the study area. However, there was no significant differences among the unrooted truncheon treatments and their respective survivorship values to further substantiate this assertion (p = 0.26). Findings in this study also suggest that planting P. afra cuttings under a nurse plant was ideal for P. afra survivorship due to the nurse plant’s ability to ameliorate the microclimate under which the cuttings can establish and grow. Despite the soil under the nurse canopy having a significantly lower mean soil water potential (-160.9 ± 200.5 kPa), compared to the open areas (-73.4 ± 55.7 kPa) (p = 0.04), the pondings under the nurse canopy still had a lower mean soil temperature (31.4 ± 5.25°C) than the treatments in the open areas (38.5 ± 2.7°C), during the harsh midday sun. These favourable characteristics are reflected in the P. afra cuttings under a nurse canopy having a higher chlorophyll fluorescence (0.76 ± 0.06). compared to those planted in open areas (0.73 ± 0.13), suggesting that the P. afra cuttings in the former treatment had a higher photosynthetic efficiency compared to those in the latter, despite there being no statistically significant difference in chlorophyll fluorescence between the treatments (p = 0.14). Although these findings suggest that applying these modifications to planting P. afra, having achieved its objective of increasing survivorship to well over 50%, is likely to produce favourable results not only in overall survivorship, but also in fast-tracking arid thicket rehabilitation and restoration, further research on these rehabilitation techniques and their effectiveness is required. Furthermore, the downside to these treatments is that they are costly and time consuming, which puts the feasibility of large-scale programmes using these applications into question. Further investigation is required to determine ways in which the cost-effectiveness of these applications can be enhanced. , Thesis (MSc) -- Faculty of Science, Environmental Science, 2023
- Full Text:
- Date Issued: 2023-03-31
On legal expressivism, incorporeal injuries and the equal protection clause: an analysis through the lens of the Civil Union Act
- Authors: Tsele, Michael Vuyo
- Date: 2022-10-14
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/405434 , vital:70171
- Description: Thesis embargoed. To be released in 2024. , Thesis (LLM) -- Faculty of Law, Law, 2022
- Full Text:
- Date Issued: 2022-10-14
- Authors: Tsele, Michael Vuyo
- Date: 2022-10-14
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/405434 , vital:70171
- Description: Thesis embargoed. To be released in 2024. , Thesis (LLM) -- Faculty of Law, Law, 2022
- Full Text:
- Date Issued: 2022-10-14
An exploratory study on the impact of three critical incidents on SMEs within the Petroleum retail sector in South Africa
- Authors: Makhaya, Humbulani Portia
- Date: 2022-10-14
- Subjects: Strikes and lockouts Petroleum industry South Africa , Motor fuels Taxation South Africa , Stockout South Africa , Small and medium enterprises South Africa , Service stations Location South Africa
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/403025 , vital:69915
- Description: The purpose of this study was to investigate the impact of three critical incidents with a direct effect on Small and Medium Enterprises (SMEs) within the Petroleum retail sector in South Africa. This study assessed three specific areas: (1) the impact of fuel levy increase on Petroleum retailers, (2) explore how fuel stock-outs are experienced by the SMEs, and (3) the effects of fuel distributors' strike on SMEs in the petroleum sector in South Africa. To address the research objectives, the study employed a qualitative research approach, based on a narrative research design. Primary data was collected through semi-structured interviews conducted with six SMEs in the fuel retail business in Johannesburg. An interview guide was used. Findings highlighted that the location of fuel retail SMEs is an important determinant of how the fuel retailers are affected by these three critical incidents of fuel levy increases, stock-outs and strikes. The study found that while the fuel levy increases are felt through reduced sales volumes, the impact is not the same across fuel retailers. The study revealed that the elasticity of demand varies depending on the location for which it is elastics for those retailers in high Living Standards Measure (LSM) locations and inelastic for those located in lower LSM locations. It was found that the impact is much less for those fuel retailers located in affluent suburbs with a high LSM. In locations such as Beyers Naude and Radiokop in Northern Johannesburg with a high LSM, the demand for fuel remains constant irrespective of price increases. The locations are also less likely to be adversely affected by protest actions. Concerning SMEs’ experiences of fuel stock-outs, the study found that stock-outs impact fuel retail business operations through overhead costs that are incurred while the fuel stations are out of stock. The small margins make it impossible for fuel retailers to quickly recover, as their profitability is dependent on sales volumes, which are compromised when there are stock-outs. Fuel retailers also suffer from reduced future sales volumes due to waning customer loyalty. Finally, the study found that the occurrence of wage-related strikes is minimal due to the nature of collective agreements that are signed within the sector. However, protests actions were found to have deleterious effects on the fuel retailer situated in lower LSM locations. , Thesis (MBA) -- Faculty of Commerce, Rhodes Business School, 2022
- Full Text:
- Date Issued: 2022-10-14
- Authors: Makhaya, Humbulani Portia
- Date: 2022-10-14
- Subjects: Strikes and lockouts Petroleum industry South Africa , Motor fuels Taxation South Africa , Stockout South Africa , Small and medium enterprises South Africa , Service stations Location South Africa
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/403025 , vital:69915
- Description: The purpose of this study was to investigate the impact of three critical incidents with a direct effect on Small and Medium Enterprises (SMEs) within the Petroleum retail sector in South Africa. This study assessed three specific areas: (1) the impact of fuel levy increase on Petroleum retailers, (2) explore how fuel stock-outs are experienced by the SMEs, and (3) the effects of fuel distributors' strike on SMEs in the petroleum sector in South Africa. To address the research objectives, the study employed a qualitative research approach, based on a narrative research design. Primary data was collected through semi-structured interviews conducted with six SMEs in the fuel retail business in Johannesburg. An interview guide was used. Findings highlighted that the location of fuel retail SMEs is an important determinant of how the fuel retailers are affected by these three critical incidents of fuel levy increases, stock-outs and strikes. The study found that while the fuel levy increases are felt through reduced sales volumes, the impact is not the same across fuel retailers. The study revealed that the elasticity of demand varies depending on the location for which it is elastics for those retailers in high Living Standards Measure (LSM) locations and inelastic for those located in lower LSM locations. It was found that the impact is much less for those fuel retailers located in affluent suburbs with a high LSM. In locations such as Beyers Naude and Radiokop in Northern Johannesburg with a high LSM, the demand for fuel remains constant irrespective of price increases. The locations are also less likely to be adversely affected by protest actions. Concerning SMEs’ experiences of fuel stock-outs, the study found that stock-outs impact fuel retail business operations through overhead costs that are incurred while the fuel stations are out of stock. The small margins make it impossible for fuel retailers to quickly recover, as their profitability is dependent on sales volumes, which are compromised when there are stock-outs. Fuel retailers also suffer from reduced future sales volumes due to waning customer loyalty. Finally, the study found that the occurrence of wage-related strikes is minimal due to the nature of collective agreements that are signed within the sector. However, protests actions were found to have deleterious effects on the fuel retailer situated in lower LSM locations. , Thesis (MBA) -- Faculty of Commerce, Rhodes Business School, 2022
- Full Text:
- Date Issued: 2022-10-14
COVID19 and accountability in South Africa: legislation, ethics and disaster risk management
- Authors: Chapman, Emma Deidre
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/419565 , vital:71655
- Description: Embargoed. Possible release in 2026 pending publication. , Thesis (MSC Pharm) -- Faculty of Pharmacy, 2023
- Full Text:
- Date Issued: 2023-10-13
- Authors: Chapman, Emma Deidre
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/419565 , vital:71655
- Description: Embargoed. Possible release in 2026 pending publication. , Thesis (MSC Pharm) -- Faculty of Pharmacy, 2023
- Full Text:
- Date Issued: 2023-10-13
Development and assessment of gastric-retentive sustained release metronidazole microcapsules
- Authors: Makan, Anjana
- Date: 2017
- Subjects: Metronidazole , Drug delivery systems , Helicobacter pylori , High performance liquid chromatography , Gas chromatography , Drugs , Drugs Controlled release
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/59240 , vital:27491
- Description: Helicobacter pylori is one of the most common pathogenic bacterial infections and is the leading cause of gastritis, gastroduodenal ulcer disease and gastric cancers. Studies have revealed the prevalence of Helicobacter pylori is high in many countries around the globe. Although Helicobacter pylori is highly sensitive to antimicrobial agents in vitro the clinical eradication rate of the disease is still low. The instability of API at gastric pH, low concentration of API in the gastric mucosa and short gastric residence times are the main reasons for poor eradication rates. The high prevalence rate of this disease necessitates the design and development of gastric-retentive site specific oral dosage forms for the optimized delivery of existing therapeutic molecules and may be an approach to improving the eradication rate of Helicobacter pylori. Metronidazole (MTZ) is a 5-nitroimidazole derivative that exhibits antibiotic and antiprotozoal activity. MTZ is used in combination with other compounds for the treatment of Helicobacter pylori in peptic ulcer disease. MTZ is a potential candidate for inclusion in a sustained release gastric-retentive delivery system that acts in the stomach and since it is unstable in the intestinal/colonic environment enhancing gastric residence time would be a therapeutic advantage. MTZ is a cost-effective therapy that exhibits good anti-microbial activity and has a favourable pharmacokinetic profile. A sustained release gastric-retentive formulation is therefore proposed as an approach to enhance the local delivery of MTZ and improve treatment outcomes for patients infected with Helicobacter pylori. A stability indicating Reversed-Phase High Performance Liquid Chromatography (RP- HPLC) method for the quantitation of MTZ in pharmaceutical dosage forms was developed and optimised using a Central Composite Design (CCD) approach. The RP-HPLC method was found to be linear, accurate, precise, sensitive, selective, and was applied to the analysis of MTZ in commercially available medicines. Preformulation studies were conducted as preparative work prior to manufacture gastric- retentive sustained release MTZ microcapsules. The experiments conducted were tailored for the development of sustained release MTZ microcapsules using a solvent evaporation method. The particle size and shape of the microcapsules was investigated using Scanning Electron Microscopy (SEM). MTZ- excipient compatibility studies were performed using Fourier Transform Infra-red Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC) and X-Ray Diffraction (XRD). The results revealed that no definite interaction between MTZ and intended excipients to be used for manufacture of MTZ formulations occurred. A solvent evaporation procedure was used for the manufacture of MTZ microcapsules. Preliminary formulations were manufactured using two different grades of Methocel® at various levels. In addition the impact of processing parameters on performance was also investigated. The formulations were assessed in terms of in vitro release, buoyancy, yield, encapsulation efficiency and microcapsule size. Formulation optimisation was undertaken using a CCD approach and numerical optimisation was used to predict an optimised formulation composition that would produce minimal initial MTZ release, maximum MTZ release at 12 hours and maximum buoyancy, encapsulation efficiency and yield. The kinetics of MTZ release from microcapsules was established by fitting in vitro release data to different mathematical models. Higuchi model and first-order model appeared to best fit the data as majority of the formulation batches had highest R2 values for these models. Short-term stability assessment of the optimised formulation was established by undertaking stability studies at 25°C/60% RH and 40°C/75%RH. No significant changes in any of the CQA were observed over 30 days of stability testing. A gas chromatographic (GC) method was developed and validated for the quantitation of residual acetone and n-hexane. The optimised formulation contained 213.60 ppm/g acetone and 25.23 ppm/g n-hexane which are well below the limits set for residual solvents. In conclusion, gastric-retentive sustained release MTZ microcapsules with potential for further development and optimisation have been successfully developed and assessed in these studies. , Thesis (MSc) -- Faculty of Pharmacy, Pharmacy, 2017
- Full Text:
- Date Issued: 2017
- Authors: Makan, Anjana
- Date: 2017
- Subjects: Metronidazole , Drug delivery systems , Helicobacter pylori , High performance liquid chromatography , Gas chromatography , Drugs , Drugs Controlled release
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/59240 , vital:27491
- Description: Helicobacter pylori is one of the most common pathogenic bacterial infections and is the leading cause of gastritis, gastroduodenal ulcer disease and gastric cancers. Studies have revealed the prevalence of Helicobacter pylori is high in many countries around the globe. Although Helicobacter pylori is highly sensitive to antimicrobial agents in vitro the clinical eradication rate of the disease is still low. The instability of API at gastric pH, low concentration of API in the gastric mucosa and short gastric residence times are the main reasons for poor eradication rates. The high prevalence rate of this disease necessitates the design and development of gastric-retentive site specific oral dosage forms for the optimized delivery of existing therapeutic molecules and may be an approach to improving the eradication rate of Helicobacter pylori. Metronidazole (MTZ) is a 5-nitroimidazole derivative that exhibits antibiotic and antiprotozoal activity. MTZ is used in combination with other compounds for the treatment of Helicobacter pylori in peptic ulcer disease. MTZ is a potential candidate for inclusion in a sustained release gastric-retentive delivery system that acts in the stomach and since it is unstable in the intestinal/colonic environment enhancing gastric residence time would be a therapeutic advantage. MTZ is a cost-effective therapy that exhibits good anti-microbial activity and has a favourable pharmacokinetic profile. A sustained release gastric-retentive formulation is therefore proposed as an approach to enhance the local delivery of MTZ and improve treatment outcomes for patients infected with Helicobacter pylori. A stability indicating Reversed-Phase High Performance Liquid Chromatography (RP- HPLC) method for the quantitation of MTZ in pharmaceutical dosage forms was developed and optimised using a Central Composite Design (CCD) approach. The RP-HPLC method was found to be linear, accurate, precise, sensitive, selective, and was applied to the analysis of MTZ in commercially available medicines. Preformulation studies were conducted as preparative work prior to manufacture gastric- retentive sustained release MTZ microcapsules. The experiments conducted were tailored for the development of sustained release MTZ microcapsules using a solvent evaporation method. The particle size and shape of the microcapsules was investigated using Scanning Electron Microscopy (SEM). MTZ- excipient compatibility studies were performed using Fourier Transform Infra-red Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC) and X-Ray Diffraction (XRD). The results revealed that no definite interaction between MTZ and intended excipients to be used for manufacture of MTZ formulations occurred. A solvent evaporation procedure was used for the manufacture of MTZ microcapsules. Preliminary formulations were manufactured using two different grades of Methocel® at various levels. In addition the impact of processing parameters on performance was also investigated. The formulations were assessed in terms of in vitro release, buoyancy, yield, encapsulation efficiency and microcapsule size. Formulation optimisation was undertaken using a CCD approach and numerical optimisation was used to predict an optimised formulation composition that would produce minimal initial MTZ release, maximum MTZ release at 12 hours and maximum buoyancy, encapsulation efficiency and yield. The kinetics of MTZ release from microcapsules was established by fitting in vitro release data to different mathematical models. Higuchi model and first-order model appeared to best fit the data as majority of the formulation batches had highest R2 values for these models. Short-term stability assessment of the optimised formulation was established by undertaking stability studies at 25°C/60% RH and 40°C/75%RH. No significant changes in any of the CQA were observed over 30 days of stability testing. A gas chromatographic (GC) method was developed and validated for the quantitation of residual acetone and n-hexane. The optimised formulation contained 213.60 ppm/g acetone and 25.23 ppm/g n-hexane which are well below the limits set for residual solvents. In conclusion, gastric-retentive sustained release MTZ microcapsules with potential for further development and optimisation have been successfully developed and assessed in these studies. , Thesis (MSc) -- Faculty of Pharmacy, Pharmacy, 2017
- Full Text:
- Date Issued: 2017
Variables associated with run out opportunities in cricket: coaches’ perceptions versus video analyses of the Indian Premier League 2018/2019 seasons
- Authors: Sholto-Douglas, Robert
- Date: 2022-10-14
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/365014 , vital:65670
- Description: The purpose of this investigation was to add a scientific element to the understanding of run out opportunities in T20 (twenty/twenty) formats, which would in turn, provide recommendations to players and coaches around the topic of run outs. Due to a lack of research in this field, the study was two-fold, as there is little research known on this topic. Firstly, surveying experienced coaches on what they would expect to take place during run out opportunities from different areas of the field in a T20 game. Secondly, the study looked at what happened during successful and unsuccessful run outs from different areas of the field in two Indian Premier League (IPL) seasons. The aim of the study was to determine what variables, within an area of fielding, led to a successful or non-successful run out from different zones in the field. Coaches were required to fill out a survey which asked them to give their expectations on run out opportunities during a T20 competition. The data from the questionnaire would be used to gain a greater understanding of the way coaches understand different characteristics of run outs and whether this matched the findings of the second part of this study. The second part of the study investigated run out opportunities in two consecutive IPL seasons, based on video footage, looking at how different variables impacted successful or marginally missed run out opportunities in different areas of the field and at different times of the game. The areas were put into four different zones. Zone 1 being close to the batter, zone 2 being in the inner ring, zone 3 being on the edge of the ring and zone 4 being boundary fielders. Most of the coaches believed that in zone 1 of the field, the bowler would have the most opportunities, where in fact, based on the video footage, these fell to the wicket-keeper. In zone 2 there were a larger range of fielding positions (10) that run outs fell to when analysing video footage. The coaches supported this by often naming the same fielding positions. There was a divide in zone 3. Most run out opportunities from the video footage came to extra cover, where most coaches didn’t believe that would be the case and rather mentioned mid-off and mid-on. When analysing video footage in zone 4, it had two fielding positions (long on and deep mid-wicket) make up the majority of run out chances in this area and these two positions were quoted by most of the coaches as having the most run out opportunities fall to them. Throughout the findings, as concluded from the video footage, there were some results that matched the coaches’ expectation and some results where findings from the video footage differed from the coaches’ expectations. These findings are all useful. Firstly, it validates coaching practices. Secondly, it provides coaches with greater insight as to where they aren’t getting it correct in their fielding training. In conclusion, this study found that although coaches perceptions, for the most part, matched what took place on the field, there were instances where we saw the opposite action take place. This has important practical implications for coaching and practice. , Thesis (MSc) -- Faculty of Science, Human Kinetics and Ergonomics, 2022
- Full Text:
- Date Issued: 2022-10-14
- Authors: Sholto-Douglas, Robert
- Date: 2022-10-14
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/365014 , vital:65670
- Description: The purpose of this investigation was to add a scientific element to the understanding of run out opportunities in T20 (twenty/twenty) formats, which would in turn, provide recommendations to players and coaches around the topic of run outs. Due to a lack of research in this field, the study was two-fold, as there is little research known on this topic. Firstly, surveying experienced coaches on what they would expect to take place during run out opportunities from different areas of the field in a T20 game. Secondly, the study looked at what happened during successful and unsuccessful run outs from different areas of the field in two Indian Premier League (IPL) seasons. The aim of the study was to determine what variables, within an area of fielding, led to a successful or non-successful run out from different zones in the field. Coaches were required to fill out a survey which asked them to give their expectations on run out opportunities during a T20 competition. The data from the questionnaire would be used to gain a greater understanding of the way coaches understand different characteristics of run outs and whether this matched the findings of the second part of this study. The second part of the study investigated run out opportunities in two consecutive IPL seasons, based on video footage, looking at how different variables impacted successful or marginally missed run out opportunities in different areas of the field and at different times of the game. The areas were put into four different zones. Zone 1 being close to the batter, zone 2 being in the inner ring, zone 3 being on the edge of the ring and zone 4 being boundary fielders. Most of the coaches believed that in zone 1 of the field, the bowler would have the most opportunities, where in fact, based on the video footage, these fell to the wicket-keeper. In zone 2 there were a larger range of fielding positions (10) that run outs fell to when analysing video footage. The coaches supported this by often naming the same fielding positions. There was a divide in zone 3. Most run out opportunities from the video footage came to extra cover, where most coaches didn’t believe that would be the case and rather mentioned mid-off and mid-on. When analysing video footage in zone 4, it had two fielding positions (long on and deep mid-wicket) make up the majority of run out chances in this area and these two positions were quoted by most of the coaches as having the most run out opportunities fall to them. Throughout the findings, as concluded from the video footage, there were some results that matched the coaches’ expectation and some results where findings from the video footage differed from the coaches’ expectations. These findings are all useful. Firstly, it validates coaching practices. Secondly, it provides coaches with greater insight as to where they aren’t getting it correct in their fielding training. In conclusion, this study found that although coaches perceptions, for the most part, matched what took place on the field, there were instances where we saw the opposite action take place. This has important practical implications for coaching and practice. , Thesis (MSc) -- Faculty of Science, Human Kinetics and Ergonomics, 2022
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- Date Issued: 2022-10-14
Transfer pricing: an analysis of legislation in the southern African Customs Union
- Authors: Patel, Nabil Ahmed
- Date: 2022-04-06
- Subjects: Transfer pricing
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/241482 , vital:50943
- Description: Transfer pricing is defined as the setting of the price for goods sold and services rendered between related entities. For example, if a subsidiary company sells goods or renders services to its holding company or a sister company, the price charged is referred to as the transfer price. Transfer pricing can be used to manipulate profits and facilitate tax evasion. Therefore, it is important that countries enact transfer pricing legislation to prevent this. The United Nations (UN) and Organisation for Economic Co-operation and Development (OECD) guideline documents form the basis for most global legislation and conventions dealing with transfer pricing. The over-arching goal of this research was to investigate whether transfer pricing legislation in the Southern African Customs Union (SACU) aligns between SACU countries and with the OECD Guidelines and the UN Manual. The research applied a legal interpretive doctrinal research methodology and a qualitative research method. The data comprised primary legislation in the SACU countries, transfer pricing guidelines issued by revenue authorities in the SACU, OECD Guidelines, the UN Manual and journal articles. It was found in this study that certain aspects of transfer pricing legislation in the SACU are not fully aligned to each other and to the OECD Guidelines and the UN Manual. This study proposed recommendations to improve transfer pricing legislation in the SACU. These improvements include the introduction of transfer pricing legislation in Eswatini and Lesotho, and updating transfer pricing legislation in Namibia and South Africa in terms of the latest versions of the OECD Guidelines and the UN Manual. , Thesis (MCom) -- Faculty of Commerce, Accounting, 2022
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- Date Issued: 2022-04-06
- Authors: Patel, Nabil Ahmed
- Date: 2022-04-06
- Subjects: Transfer pricing
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/241482 , vital:50943
- Description: Transfer pricing is defined as the setting of the price for goods sold and services rendered between related entities. For example, if a subsidiary company sells goods or renders services to its holding company or a sister company, the price charged is referred to as the transfer price. Transfer pricing can be used to manipulate profits and facilitate tax evasion. Therefore, it is important that countries enact transfer pricing legislation to prevent this. The United Nations (UN) and Organisation for Economic Co-operation and Development (OECD) guideline documents form the basis for most global legislation and conventions dealing with transfer pricing. The over-arching goal of this research was to investigate whether transfer pricing legislation in the Southern African Customs Union (SACU) aligns between SACU countries and with the OECD Guidelines and the UN Manual. The research applied a legal interpretive doctrinal research methodology and a qualitative research method. The data comprised primary legislation in the SACU countries, transfer pricing guidelines issued by revenue authorities in the SACU, OECD Guidelines, the UN Manual and journal articles. It was found in this study that certain aspects of transfer pricing legislation in the SACU are not fully aligned to each other and to the OECD Guidelines and the UN Manual. This study proposed recommendations to improve transfer pricing legislation in the SACU. These improvements include the introduction of transfer pricing legislation in Eswatini and Lesotho, and updating transfer pricing legislation in Namibia and South Africa in terms of the latest versions of the OECD Guidelines and the UN Manual. , Thesis (MCom) -- Faculty of Commerce, Accounting, 2022
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- Date Issued: 2022-04-06
A case study on responsible leadership in a renewable energy organisation in the Eastern Cape
- Authors: Mdingi, Chulumanco
- Date: 2022-06
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/419101 , vital:71616
- Description: This research was a case study of responsible leadership in a renewable energy organisation in the Eastern Cape. The study aimed to understand and describe how a renewable energy organisation applies responsible leadership to build trust. The four objectives of the study were namely to: (1) describe how the organisation interacts with its stakeholders to build trust; (2) understand how the members of the organisation demonstrate the characteristics of responsible leadership; (3) understand how different stakeholders perceive and experience the interaction of the company with established stakeholders; (4) make recommendations that a renewable energy organisation can exercise the characteristics of responsible leadership to develop its stakeholder engagement framework. In the study the stakeholder theory was applied as the theoretical framework, and the theory encourages organisations to determine the "power, legitimacy, and urgency" of stakeholders with whom they interact. A qualitative approach was used in this study. The data collection method was semi-structured interviews for all 12 participants. Data were analysed through a deductive thematic approach to identify, analyse and report patterns or themes within the data collected. The study showed that the wind farm unintentionally applies some components of responsible leadership among its stakeholders. Openness, transparency, and communication are critical actions that this organisation undertakes to cultivate trust among both its internal and external stakeholders. External stakeholders experience this organisation differently. There are mixed feelings regarding how the wind farm conducts its stakeholder engagement activities, particularly relating to landowners and government institutions. A stakeholder engagement framework is imperative if an organisation is to maintain cordial relations with its stakeholders. , Thesis (MBA) -- Faculty of Commerce, Rhodes Business School, 2023
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- Date Issued: 2022-06
- Authors: Mdingi, Chulumanco
- Date: 2022-06
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/419101 , vital:71616
- Description: This research was a case study of responsible leadership in a renewable energy organisation in the Eastern Cape. The study aimed to understand and describe how a renewable energy organisation applies responsible leadership to build trust. The four objectives of the study were namely to: (1) describe how the organisation interacts with its stakeholders to build trust; (2) understand how the members of the organisation demonstrate the characteristics of responsible leadership; (3) understand how different stakeholders perceive and experience the interaction of the company with established stakeholders; (4) make recommendations that a renewable energy organisation can exercise the characteristics of responsible leadership to develop its stakeholder engagement framework. In the study the stakeholder theory was applied as the theoretical framework, and the theory encourages organisations to determine the "power, legitimacy, and urgency" of stakeholders with whom they interact. A qualitative approach was used in this study. The data collection method was semi-structured interviews for all 12 participants. Data were analysed through a deductive thematic approach to identify, analyse and report patterns or themes within the data collected. The study showed that the wind farm unintentionally applies some components of responsible leadership among its stakeholders. Openness, transparency, and communication are critical actions that this organisation undertakes to cultivate trust among both its internal and external stakeholders. External stakeholders experience this organisation differently. There are mixed feelings regarding how the wind farm conducts its stakeholder engagement activities, particularly relating to landowners and government institutions. A stakeholder engagement framework is imperative if an organisation is to maintain cordial relations with its stakeholders. , Thesis (MBA) -- Faculty of Commerce, Rhodes Business School, 2023
- Full Text:
- Date Issued: 2022-06
An empirical analysis of the asset price monetary policy transmission channel in South Africa
- Authors: Du Preez, Wilhelmus Petrus
- Date: 2021-10
- Subjects: Monetary policy South Africa , Banks and banking, Central South Africa , Transmission mechanism (Monetary policy) South Africa , Capital assets pricing model , Securities South Africa , Stocks Prices South Africa , Repurchase agreements South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/190318 , vital:44983
- Description: The asset pricing channel of monetary policy transmission breeds an interesting study. There has been an ongoing debate to determine whether monetary policy committees should directly influence the asset pricing channel through changes in the central bank control interest rate or whether monetary policy committees should refrain from targeting the asset pricing channel to meet their policy objectives. The study aims to critically analysis the asset pricing channel, firstly on a global context to set the scene and then to critically focus on the study performed by Muroyiwa et al. (2017) who conducted a study on the South African monetary policy and its interdependence on the stock market through utilisation of an SVAR model. It was concluded that monetary policy does significantly influence stock prices. The purpose of this study is to build on the results which have been formed by Muroyiwa et al. (2017) and to expand on the period under analysis which encapsulates 1999:01 to 2007:12 in order to conclude whether there are conflicting conclusions or conclusions which build on what has already been done. The results from the research shows that when the monetary policy committee decides to influence changes in the repo rate, the repo rate will have a direct effect on the asset markets, the indexes that were used to represent the asset market are the all share index, industrial 15 index and the financial 15 index. Furthermore. The study which has expanded the period under analysis has supplemented and built on the results provided by Muroyiwa et al. (2017). , Thesis (MCom) -- Faculty of Commerce, Economics and Economic History, 2021
- Full Text:
- Date Issued: 2021-10
- Authors: Du Preez, Wilhelmus Petrus
- Date: 2021-10
- Subjects: Monetary policy South Africa , Banks and banking, Central South Africa , Transmission mechanism (Monetary policy) South Africa , Capital assets pricing model , Securities South Africa , Stocks Prices South Africa , Repurchase agreements South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/190318 , vital:44983
- Description: The asset pricing channel of monetary policy transmission breeds an interesting study. There has been an ongoing debate to determine whether monetary policy committees should directly influence the asset pricing channel through changes in the central bank control interest rate or whether monetary policy committees should refrain from targeting the asset pricing channel to meet their policy objectives. The study aims to critically analysis the asset pricing channel, firstly on a global context to set the scene and then to critically focus on the study performed by Muroyiwa et al. (2017) who conducted a study on the South African monetary policy and its interdependence on the stock market through utilisation of an SVAR model. It was concluded that monetary policy does significantly influence stock prices. The purpose of this study is to build on the results which have been formed by Muroyiwa et al. (2017) and to expand on the period under analysis which encapsulates 1999:01 to 2007:12 in order to conclude whether there are conflicting conclusions or conclusions which build on what has already been done. The results from the research shows that when the monetary policy committee decides to influence changes in the repo rate, the repo rate will have a direct effect on the asset markets, the indexes that were used to represent the asset market are the all share index, industrial 15 index and the financial 15 index. Furthermore. The study which has expanded the period under analysis has supplemented and built on the results provided by Muroyiwa et al. (2017). , Thesis (MCom) -- Faculty of Commerce, Economics and Economic History, 2021
- Full Text:
- Date Issued: 2021-10