The reading to learn pedagogy in South African inclusive English First Additional Language classrooms: successes and challenges
- Authors: Moyo, Sheron
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/463735 , vital:76436
- Description: Reading to Learn (RtL) has been frequently suggested for students not meeting grade-appropriate reading standards. However, its achievements and shortcomings have not been examined in inclusive education. In light of this, the main goal of this study was to explore the successes and challenges of this methodology in grade 9 English First Additional Language (FAL) inclusive classrooms across four schools in the Northern Cape Province’s John Taolo Gaetsewe District. In light of the grave concerns about literacy development in South African schools, this methodology was created to fulfil the literacy needs of students from underprivileged groups in Australia. This qualitative study was grounded in social constructivist theory and an interpretative paradigm. The research used an exploratory case study comprising four participants who were purposively recruited and empowered with RtL between 2016 and 2022. The data-gathering methods used were semi-structured interviews, focus group discussions, and classroom observations to get insights into the achievements and shortcomings of the RtL pedagogy in inclusive classrooms. The qualitative data in this study was analysed using thematic analysis. The study’s findings revealed that the RtL pedagogy gave students who faced reading obstacles in inclusive classes the skills needed to read, read with meaning, and improve as readers and writers through its six-step scaffolding interactive cycle. There were challenges in employing the RtL pedagogy in inclusive classes, such as it is time-consuming and makes it difficult for teachers to adhere to the time frame stipulated by the annual teaching plan. Nevertheless, the study’s findings showed that the advantages of the RtL pedagogy outweigh the challenges. , Thesis (MEd) -- Faculty of Education, Institute for the Study of Englishes of Africa, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Moyo, Sheron
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/463735 , vital:76436
- Description: Reading to Learn (RtL) has been frequently suggested for students not meeting grade-appropriate reading standards. However, its achievements and shortcomings have not been examined in inclusive education. In light of this, the main goal of this study was to explore the successes and challenges of this methodology in grade 9 English First Additional Language (FAL) inclusive classrooms across four schools in the Northern Cape Province’s John Taolo Gaetsewe District. In light of the grave concerns about literacy development in South African schools, this methodology was created to fulfil the literacy needs of students from underprivileged groups in Australia. This qualitative study was grounded in social constructivist theory and an interpretative paradigm. The research used an exploratory case study comprising four participants who were purposively recruited and empowered with RtL between 2016 and 2022. The data-gathering methods used were semi-structured interviews, focus group discussions, and classroom observations to get insights into the achievements and shortcomings of the RtL pedagogy in inclusive classrooms. The qualitative data in this study was analysed using thematic analysis. The study’s findings revealed that the RtL pedagogy gave students who faced reading obstacles in inclusive classes the skills needed to read, read with meaning, and improve as readers and writers through its six-step scaffolding interactive cycle. There were challenges in employing the RtL pedagogy in inclusive classes, such as it is time-consuming and makes it difficult for teachers to adhere to the time frame stipulated by the annual teaching plan. Nevertheless, the study’s findings showed that the advantages of the RtL pedagogy outweigh the challenges. , Thesis (MEd) -- Faculty of Education, Institute for the Study of Englishes of Africa, 2024
- Full Text:
- Date Issued: 2024-10-11
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
Continuous flow synthesis of a key intermediate towards the antidiabetic drug repaglinide
- Authors: Williams, Arushan
- Date: 2023-04
- Subjects: Diabetes -- Miscellanea -- South Africa , Diabetes –Treatment
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/61064 , vital:69715
- Description: Across the world, diabetes is one of the leading causes of deaths attributed to noncommunicable diseases (NCDs). In Africa, a huge proportion of African countries’ annual healthcare budgets are consumed by diabetes (7 %) with many already experiencing healthcare budget deficits. The prevalence of diabetes is rapidly growing and threatens the economic productivity and livelihood of many families within the region. The world leaders have invested heavily in reducing the pandemic by focusing on increasing the availability of affordable essential medicines in developing countries. The majority of diabetes cases are due to type 2 diabetes (90 %) and may be treated using oral hypoglycaemic drugs (OHDs). Repaglinide (REP) is a non-sulfonylurea insulin secretagogue (meglitinide) with greater HbA1c reduction than metformin in newly onset type 2 diabetic patients, however due to the high price of REP outside Asia, cheaper and less effective OHDs are prescribed to patients. Many of the reported synthetic routes towards REP utilize a key intermediate, 2-(3-ethoxy-4- iethoxycarbonyl)phenyl)acetic acid. The key intermediate contributes significantly to the price of REP as many of the intermediate’s synthetic routes suffer from long reaction times, low yields and industrial complex approaches. Therefore, this has prompted us to investigate an efficient process towards the synthesis of 2-(3-ethoxy-4-(ethoxycarbonyl)phenyl)acetic acid using multiple continuous flow systems. , Thesis (MSc) -- Faculty of Science, School of Biomolecular and Chemical Sciences, 2023
- Full Text:
- Date Issued: 2023-04
- Authors: Williams, Arushan
- Date: 2023-04
- Subjects: Diabetes -- Miscellanea -- South Africa , Diabetes –Treatment
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/61064 , vital:69715
- Description: Across the world, diabetes is one of the leading causes of deaths attributed to noncommunicable diseases (NCDs). In Africa, a huge proportion of African countries’ annual healthcare budgets are consumed by diabetes (7 %) with many already experiencing healthcare budget deficits. The prevalence of diabetes is rapidly growing and threatens the economic productivity and livelihood of many families within the region. The world leaders have invested heavily in reducing the pandemic by focusing on increasing the availability of affordable essential medicines in developing countries. The majority of diabetes cases are due to type 2 diabetes (90 %) and may be treated using oral hypoglycaemic drugs (OHDs). Repaglinide (REP) is a non-sulfonylurea insulin secretagogue (meglitinide) with greater HbA1c reduction than metformin in newly onset type 2 diabetic patients, however due to the high price of REP outside Asia, cheaper and less effective OHDs are prescribed to patients. Many of the reported synthetic routes towards REP utilize a key intermediate, 2-(3-ethoxy-4- iethoxycarbonyl)phenyl)acetic acid. The key intermediate contributes significantly to the price of REP as many of the intermediate’s synthetic routes suffer from long reaction times, low yields and industrial complex approaches. Therefore, this has prompted us to investigate an efficient process towards the synthesis of 2-(3-ethoxy-4-(ethoxycarbonyl)phenyl)acetic acid using multiple continuous flow systems. , Thesis (MSc) -- Faculty of Science, School of Biomolecular and Chemical Sciences, 2023
- Full Text:
- Date Issued: 2023-04
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
In silico identification of natural inhibitory compounds against the Mycobacterium tuberculosis Enzyme Pyrazinamidase using high-throughput virtual screening techniques
- Authors: Kenyon, Thomas
- Date: 2021-10-29
- Subjects: Mycobacterium tuberculosis , Pyrazinamide , Molecular dynamics , High throughput screening (Drug development) , Mutagenesis , South African Natural Compounds database (SANCDB)
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192074 , vital:45193
- Description: Tuberculosis (TB) is most commonly a pulmonary infection caused by the bacterium Mycobacterium tuberculosis. With the exception of the COVID-19 pandemic, TB was the most common cause of death due to an infectious disease for a number of years up until 2020. In 2019, 10 million people fell ill with TB worldwide and 1.4 million people died (WHO, 2020a). Additionally, multidrug-resistant TB (MDR-TB) remains a public health crisis and a health security threat. A global total of 206 030 people with multidrug- or rifampicin-resistant TB (MDR/RR-TB) were reported in 2019, a 10% increase from 186 883 in 2018. South Africa is ranked among the 48 high TB burden countries, with an estimated 360 000 people falling ill in 2019, resulting in 58 000 deaths, the majority of which being among people living with HIV. Unlike HIV, however, TB is a curable disease when managed correctly with long durations of antitubercular chemotherapy. Pyrazinamide (PZA) is an important first-line tuberculosis drug unique for its activity against latent TB. PZA is a prodrug, being converted into its active form, pyrazinoic acid (POA) by the Mtb gene pncA, coding for the pyrazinamidase enzyme (PZase). TB resistance to first-line drugs such as PZA is commonly associated with mutations in the pncA/PZase enzyme. This study aimed to identify potential novel inhibitors that bind to the active site of PZase. By making use of molecular docking studies and molecular dynamics (MD) simulations, high throughput virtual screening was performed on 623 compounds from the South African Natural Compounds database (SANCDB; https://sancdb.rubi.ru.ac.za). Ligands that selectively bound to the PZase active site were identified using docking studies, followed by MD simulations to assess ligand-PZase complex stability, Finally, hit compounds identified from the first round of MD simulations were screened again against PZase structures with high confidence point mutations known to infer PZA resistance in order to identify any novel compounds which had inhibitory potential against both WT and mutant forms of the PZase enzyme. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Kenyon, Thomas
- Date: 2021-10-29
- Subjects: Mycobacterium tuberculosis , Pyrazinamide , Molecular dynamics , High throughput screening (Drug development) , Mutagenesis , South African Natural Compounds database (SANCDB)
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192074 , vital:45193
- Description: Tuberculosis (TB) is most commonly a pulmonary infection caused by the bacterium Mycobacterium tuberculosis. With the exception of the COVID-19 pandemic, TB was the most common cause of death due to an infectious disease for a number of years up until 2020. In 2019, 10 million people fell ill with TB worldwide and 1.4 million people died (WHO, 2020a). Additionally, multidrug-resistant TB (MDR-TB) remains a public health crisis and a health security threat. A global total of 206 030 people with multidrug- or rifampicin-resistant TB (MDR/RR-TB) were reported in 2019, a 10% increase from 186 883 in 2018. South Africa is ranked among the 48 high TB burden countries, with an estimated 360 000 people falling ill in 2019, resulting in 58 000 deaths, the majority of which being among people living with HIV. Unlike HIV, however, TB is a curable disease when managed correctly with long durations of antitubercular chemotherapy. Pyrazinamide (PZA) is an important first-line tuberculosis drug unique for its activity against latent TB. PZA is a prodrug, being converted into its active form, pyrazinoic acid (POA) by the Mtb gene pncA, coding for the pyrazinamidase enzyme (PZase). TB resistance to first-line drugs such as PZA is commonly associated with mutations in the pncA/PZase enzyme. This study aimed to identify potential novel inhibitors that bind to the active site of PZase. By making use of molecular docking studies and molecular dynamics (MD) simulations, high throughput virtual screening was performed on 623 compounds from the South African Natural Compounds database (SANCDB; https://sancdb.rubi.ru.ac.za). Ligands that selectively bound to the PZase active site were identified using docking studies, followed by MD simulations to assess ligand-PZase complex stability, Finally, hit compounds identified from the first round of MD simulations were screened again against PZase structures with high confidence point mutations known to infer PZA resistance in order to identify any novel compounds which had inhibitory potential against both WT and mutant forms of the PZase enzyme. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2021
- Full Text:
- Date Issued: 2021-10-29
Remote fidelity of Container-Based Network Emulators
- Authors: Peach, Schalk Willem
- Date: 2021-10-29
- Subjects: Computer networks Security measures , Intrusion detection systems (Computer security) , Computer security , Host-based intrusion detection systems (Computer security) , Emulators (Computer programs) , Computer network protocols , Container-Based Network Emulators (CBNEs) , Network Experimentation Platforms (NEPs)
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192141 , vital:45199
- Description: This thesis examines if Container-Based Network Emulators (CBNEs) are able to instantiate emulated nodes that provide sufficient realism to be used in information security experiments. The realism measure used is based on the information available from the point of view of a remote attacker. During the evaluation of a Container-Based Network Emulator (CBNE) as a platform to replicate production networks for information security experiments, it was observed that nmap fingerprinting returned Operating System (OS) family and version results inconsistent with that of the host Operating System (OS). CBNEs utilise Linux namespaces, the technology used for containerisation, to instantiate \emulated" hosts for experimental networks. Linux containers partition resources of the host OS to create lightweight virtual machines that share a single OS kernel. As all emulated hosts share the same kernel in a CBNE network, there is a reasonable expectation that the fingerprints of the host OS and emulated hosts should be the same. Based on how CBNEs instantiate emulated networks and that fingerprinting returned inconsistent results, it was hypothesised that the technologies used to construct CBNEs are capable of influencing fingerprints generated by utilities such as nmap. It was predicted that hosts emulated using different CBNEs would show deviations in remotely generated fingerprints when compared to fingerprints generated for the host OS. An experimental network consisting of two emulated hosts and a Layer 2 switch was instantiated on multiple CBNEs using the same host OS. Active and passive fingerprinting was conducted between the emulated hosts to generate fingerprints and OS family and version matches. Passive fingerprinting failed to produce OS family and version matches as the fingerprint databases for these utilities are no longer maintained. For active fingerprinting the OS family results were consistent between tested systems and the host OS, though OS version results reported was inconsistent. A comparison of the generated fingerprints revealed that for certain CBNEs fingerprint features related to network stack optimisations of the host OS deviated from other CBNEs and the host OS. The hypothesis that CBNEs can influence remotely generated fingerprints was partially confirmed. One CBNE system modified Linux kernel networking options, causing a deviation from fingerprints generated for other tested systems and the host OS. The hypothesis was also partially rejected as the technologies used by CBNEs do not influence the remote fidelity of emulated hosts. , Thesis (MSc) -- Faculty of Science, Computer Science, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Peach, Schalk Willem
- Date: 2021-10-29
- Subjects: Computer networks Security measures , Intrusion detection systems (Computer security) , Computer security , Host-based intrusion detection systems (Computer security) , Emulators (Computer programs) , Computer network protocols , Container-Based Network Emulators (CBNEs) , Network Experimentation Platforms (NEPs)
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192141 , vital:45199
- Description: This thesis examines if Container-Based Network Emulators (CBNEs) are able to instantiate emulated nodes that provide sufficient realism to be used in information security experiments. The realism measure used is based on the information available from the point of view of a remote attacker. During the evaluation of a Container-Based Network Emulator (CBNE) as a platform to replicate production networks for information security experiments, it was observed that nmap fingerprinting returned Operating System (OS) family and version results inconsistent with that of the host Operating System (OS). CBNEs utilise Linux namespaces, the technology used for containerisation, to instantiate \emulated" hosts for experimental networks. Linux containers partition resources of the host OS to create lightweight virtual machines that share a single OS kernel. As all emulated hosts share the same kernel in a CBNE network, there is a reasonable expectation that the fingerprints of the host OS and emulated hosts should be the same. Based on how CBNEs instantiate emulated networks and that fingerprinting returned inconsistent results, it was hypothesised that the technologies used to construct CBNEs are capable of influencing fingerprints generated by utilities such as nmap. It was predicted that hosts emulated using different CBNEs would show deviations in remotely generated fingerprints when compared to fingerprints generated for the host OS. An experimental network consisting of two emulated hosts and a Layer 2 switch was instantiated on multiple CBNEs using the same host OS. Active and passive fingerprinting was conducted between the emulated hosts to generate fingerprints and OS family and version matches. Passive fingerprinting failed to produce OS family and version matches as the fingerprint databases for these utilities are no longer maintained. For active fingerprinting the OS family results were consistent between tested systems and the host OS, though OS version results reported was inconsistent. A comparison of the generated fingerprints revealed that for certain CBNEs fingerprint features related to network stack optimisations of the host OS deviated from other CBNEs and the host OS. The hypothesis that CBNEs can influence remotely generated fingerprints was partially confirmed. One CBNE system modified Linux kernel networking options, causing a deviation from fingerprints generated for other tested systems and the host OS. The hypothesis was also partially rejected as the technologies used by CBNEs do not influence the remote fidelity of emulated hosts. , Thesis (MSc) -- Faculty of Science, Computer Science, 2021
- Full Text:
- Date Issued: 2021-10-29
Investigating the key performance factors in circumventing the effects of sanctions imposed by the gulf cooperation council (gcc). A case study of qatar airways (2016-2020)
- Authors: Mutebuka , Tonderai
- Date: 2021-00
- Subjects: Industry 4.0 , Airport authorities , Aviation
- Language: English
- Type: Master's/Doctoral theses , text
- Identifier: http://hdl.handle.net/11260/6457 , vital:46285
- Description: The study aimed to investigate the key performance factors in circumventing the effects of sanctions imposed by the Gulf Cooperation Council (GCC) on Qatar. A case study of Qatar Airways (2016-2020) in the form of desktop analysis/document review coupled with observation was carried out. Effects of sanctions identified included the closure of air corridors, increased operational costs, and in-access to services from certain insurance companies and travel agencies. From the results, management was observed to have implemented the following measures to caution the airlines from the effects of sanctions: close monitoring of flights, integration of all operations activities, network expansion, effective marketing, continued engagement with the sanction imposers, consistency in terms of management action and the messages communicated and fighting sanctions legally through the courts. Key Success Factors (KSFs) were extracted from these management initiatives credited with the continued success of Qatar Airways which included marketing, Corporate Social Responsibility (CSR), service quality, marketing, security, resources availability, technology, synergies, diversification, and government support. From the management initiatives, Key Performance Indicators (KPIs) were also extracted which acted as barometers to indicate the progress being made by implementation of these management initiatives in the fight against sanctions. These included accolades, passengers/cargo, fleet size, revenue, employees, and crisis indicators. These findings from the study can be used by other airlines that may find themselves under sanctions. , Thesis (MCom) -- Faculty of Commerce and Administration, 2021
- Full Text:
- Date Issued: 2021-00
- Authors: Mutebuka , Tonderai
- Date: 2021-00
- Subjects: Industry 4.0 , Airport authorities , Aviation
- Language: English
- Type: Master's/Doctoral theses , text
- Identifier: http://hdl.handle.net/11260/6457 , vital:46285
- Description: The study aimed to investigate the key performance factors in circumventing the effects of sanctions imposed by the Gulf Cooperation Council (GCC) on Qatar. A case study of Qatar Airways (2016-2020) in the form of desktop analysis/document review coupled with observation was carried out. Effects of sanctions identified included the closure of air corridors, increased operational costs, and in-access to services from certain insurance companies and travel agencies. From the results, management was observed to have implemented the following measures to caution the airlines from the effects of sanctions: close monitoring of flights, integration of all operations activities, network expansion, effective marketing, continued engagement with the sanction imposers, consistency in terms of management action and the messages communicated and fighting sanctions legally through the courts. Key Success Factors (KSFs) were extracted from these management initiatives credited with the continued success of Qatar Airways which included marketing, Corporate Social Responsibility (CSR), service quality, marketing, security, resources availability, technology, synergies, diversification, and government support. From the management initiatives, Key Performance Indicators (KPIs) were also extracted which acted as barometers to indicate the progress being made by implementation of these management initiatives in the fight against sanctions. These included accolades, passengers/cargo, fleet size, revenue, employees, and crisis indicators. These findings from the study can be used by other airlines that may find themselves under sanctions. , Thesis (MCom) -- Faculty of Commerce and Administration, 2021
- Full Text:
- Date Issued: 2021-00
The Architecture of “Set and Setting” in Psychedelic Psychotherapy: The Design of a Mental Health Care Facility in Diepsloot, Johannesburg
- Authors: Mcilroy, Glen
- Date: 2020-09
- Subjects: Sustainable architecture -- Diepsloot -- Johannesburg , Mental health facilities -- Diepsloot -- Johannesburg
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/59084 , vital:60262
- Description: Diepsloot, Johannesburg, one of South Africa’s unique post-apartheid settlements, could be described as an island of poverty and strife amidst a sea of wealth and economic growth. The area, which began as a temporary settlement for displaced families in a time of radical change in the South African political landscape, was previously made up of large expanses of open space used for recreation, and is now an overcrowded settlement with major housing shortages and infrastructural insufficiencies. With some of the highest rates of violence against women in the world, Diepsloot shows a community rife with social issues, further exacerbated by substandard living conditions. This pervasive violence against women was shown to be perpetuated by men who have themselves been victims of violence in one form or another. With no known manner in which to seek assistance in dealing with their own traumas, perpetuate a cycle of violence through indeterminable generations. Undeniably a community in need of mental healthcare, Diepsloot currently has no facilities of this type, and little is known about the opportunity for seeking psychiatric assistance amongst members of the community. , Thesis (MA) -- Faculty of Engineering, the Built Environment, and Technology, 2020
- Full Text:
- Date Issued: 2020-09
- Authors: Mcilroy, Glen
- Date: 2020-09
- Subjects: Sustainable architecture -- Diepsloot -- Johannesburg , Mental health facilities -- Diepsloot -- Johannesburg
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/59084 , vital:60262
- Description: Diepsloot, Johannesburg, one of South Africa’s unique post-apartheid settlements, could be described as an island of poverty and strife amidst a sea of wealth and economic growth. The area, which began as a temporary settlement for displaced families in a time of radical change in the South African political landscape, was previously made up of large expanses of open space used for recreation, and is now an overcrowded settlement with major housing shortages and infrastructural insufficiencies. With some of the highest rates of violence against women in the world, Diepsloot shows a community rife with social issues, further exacerbated by substandard living conditions. This pervasive violence against women was shown to be perpetuated by men who have themselves been victims of violence in one form or another. With no known manner in which to seek assistance in dealing with their own traumas, perpetuate a cycle of violence through indeterminable generations. Undeniably a community in need of mental healthcare, Diepsloot currently has no facilities of this type, and little is known about the opportunity for seeking psychiatric assistance amongst members of the community. , Thesis (MA) -- Faculty of Engineering, the Built Environment, and Technology, 2020
- Full Text:
- Date Issued: 2020-09
Understanding the livelihoods of Zimbabwean informal traders in South Africa: the case of Makhanda
- Musiyandaka, Tariro Henrietta
- Authors: Musiyandaka, Tariro Henrietta
- Date: 2020
- Subjects: Informal sector (Economics) South Africa Makhanda , Foreign workers, Zimbabwean South Africa Makhanda Economic conditions , Foreign workers, Zimbabwean South Africa Makhanda Social conditions , Street vendors South Africa Makhanda
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/164535 , vital:41127
- Description: Increasingly, Zimbabweans are migrating from their country for both economic and political reasons, with South Africa being the primary destination. In seeking employment in South Africa, Zimbabweans face numerous initial problems, including the high unemployment rate in the country alongside restrictions on their employment in the formal economy. In this context, Zimbabweans often turn to work in the informal economy, including as informal traders. This thesis seeks to understand the lives and livelihoods of Zimbabwean informal traders in Makhanda in the Eastern Cape Province of South Africa. Drawing upon the Sustainable Livelihoods Approach, and in the light of existing literature on Zimbabweans more broadly in South Africa, the thesis examines the livelihoods of a purposeful sampled grouping of six informal traders from Zimbabwe in Makhanda. It discusses their reasons for leaving Zimbabwe, their journey from Zimbabwe to Makhanda, relationships amongst themselves and their ongoing relationships with family back home, as well as their hopes and plans for the future. It also examines more specifically their livelihood activities, the daily challenges they face in pursuing their livelihoods and concerns about their livelihood status in South Africa. Despite the many deep-rooted systemic obstacles confronting these Zimbabwean informal traders, the thesis concludes that they demonstrate significant micro-level ingenuity in pursuing their livelihoods in South Africa. , Thesis (MA) -- Faculty of Faculty of Humanities, Sociology, 2020
- Full Text:
- Date Issued: 2020
- Authors: Musiyandaka, Tariro Henrietta
- Date: 2020
- Subjects: Informal sector (Economics) South Africa Makhanda , Foreign workers, Zimbabwean South Africa Makhanda Economic conditions , Foreign workers, Zimbabwean South Africa Makhanda Social conditions , Street vendors South Africa Makhanda
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/164535 , vital:41127
- Description: Increasingly, Zimbabweans are migrating from their country for both economic and political reasons, with South Africa being the primary destination. In seeking employment in South Africa, Zimbabweans face numerous initial problems, including the high unemployment rate in the country alongside restrictions on their employment in the formal economy. In this context, Zimbabweans often turn to work in the informal economy, including as informal traders. This thesis seeks to understand the lives and livelihoods of Zimbabwean informal traders in Makhanda in the Eastern Cape Province of South Africa. Drawing upon the Sustainable Livelihoods Approach, and in the light of existing literature on Zimbabweans more broadly in South Africa, the thesis examines the livelihoods of a purposeful sampled grouping of six informal traders from Zimbabwe in Makhanda. It discusses their reasons for leaving Zimbabwe, their journey from Zimbabwe to Makhanda, relationships amongst themselves and their ongoing relationships with family back home, as well as their hopes and plans for the future. It also examines more specifically their livelihood activities, the daily challenges they face in pursuing their livelihoods and concerns about their livelihood status in South Africa. Despite the many deep-rooted systemic obstacles confronting these Zimbabwean informal traders, the thesis concludes that they demonstrate significant micro-level ingenuity in pursuing their livelihoods in South Africa. , Thesis (MA) -- Faculty of Faculty of Humanities, Sociology, 2020
- Full Text:
- Date Issued: 2020
Tetra 4-(propargyloxy)phenoxy phthalocyanines: synthesis, spectroscopic, nonlinear optical and electrocatalytic properties
- Authors: Mwanza, Daniel
- Date: 2017
- Subjects: Phthalocyanines , Nonlinear optics , Electrocatalysis , Spectrum analysis , Thermogravimetry , Phthalocyanines Spectra
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/65144 , vital:28695
- Description: This study presents the synthesis, spectroscopic, photophysical and theoretical characterisation of metal-free (H2TPrOPhOPc), cobalt (CoTPrOPhOPc) and manganese (MnTPrOPhOPc) tetra 4-(4-propargyloxy) phenoxy phthalocyanines. Thermal analysis using thermogravimetric analysis (TGA) confirmed the excellent thermal stability of synthesized tetra 4-(4- propargyloxy) phenoxy phthalocyanines. The metal complexes, CoTPrOPhOPc and MnTPrOPhOPc, exhibited better thermal stability when compared to H2TPrOPhOPc. The residual percentage weight remaining was approximately 70% for CoTPrOPhOPc and MnTPrOPhOPc and 45% for H2TPrOPhOPc after 600°C, clearly confirming the stability of the metal complexes. The MTPrOPhOPcs (where M = H2, Co and Mn) complexes exhibited excellent nonlinear optical properties with strong reverse saturable absorption (RSA), especially when 560 nm excitation laser was used. Their nonlinear optical properties followed this trend: H2TPrOPhOPc > CoTPrOPhOPc > MnTPrOPhOPc. According to the trend observed, the H2TPrOPhOPc was an excellent nonlinear optical limiter when compared to the CoTPrOPhOPc and MnTPrOPhOPc. All the investigated complexes exhibited optical limiting properties comparable to the phthalocyanine complexes reported in the literature. The MTPrOPhOPc complexes were further studied for their electrocatalytic and electroanalytical properties towards the detection of hydrogen peroxide. For the electrocatalytic studies, the synthesized complexes were immobilized onto gold electrode surfaces pre-functionalized with phenylazide (Au-PAz) monolayer. Copper (I) catalyzed alkynyl-azide cycloaddition reaction was used to covalently immobilize the MTPrOPhOPcs onto the gold electrode surfaces to form Au-PAz-MTPrOPhOPc. The MTPrOPhOPcs modified gold surfaces (Au-PAz-MTPrOPhOPc) exhibited good reproducibility and stability in various electrolyte conditions. Electrochemical and surface characterisation of the functionalised gold electrode surfaces confirmed the presence of the MTPrOPhOPcs and their electroanalysis was excellent towards electrocatalytic reduction of H2O2, with the limit of detection (LoD) and limit of quantification (LoQ) in the ^M range. The electrocatalytic reduction peaks for H2O2 were observed at -0.37 V for Au-PAz-MnTPrOPhOPc and -0.31 V for Au-PAz-CoTPrOPhOPc when Ag|AgCl pseudo-reference electrode was used. The Au-PAz-MnTPrOPhOPc and Au- PAz-CoTPrOPhOPc gold electrode surfaces showed good sensitivity and reproducibility towards the electrocatalytic reduction of hydrogen peroxide in pH 7.4 phosphate buffer solution. , Thesis (MSc) -- Faculty of Science, Chemistry, 2017
- Full Text:
- Date Issued: 2017
- Authors: Mwanza, Daniel
- Date: 2017
- Subjects: Phthalocyanines , Nonlinear optics , Electrocatalysis , Spectrum analysis , Thermogravimetry , Phthalocyanines Spectra
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/65144 , vital:28695
- Description: This study presents the synthesis, spectroscopic, photophysical and theoretical characterisation of metal-free (H2TPrOPhOPc), cobalt (CoTPrOPhOPc) and manganese (MnTPrOPhOPc) tetra 4-(4-propargyloxy) phenoxy phthalocyanines. Thermal analysis using thermogravimetric analysis (TGA) confirmed the excellent thermal stability of synthesized tetra 4-(4- propargyloxy) phenoxy phthalocyanines. The metal complexes, CoTPrOPhOPc and MnTPrOPhOPc, exhibited better thermal stability when compared to H2TPrOPhOPc. The residual percentage weight remaining was approximately 70% for CoTPrOPhOPc and MnTPrOPhOPc and 45% for H2TPrOPhOPc after 600°C, clearly confirming the stability of the metal complexes. The MTPrOPhOPcs (where M = H2, Co and Mn) complexes exhibited excellent nonlinear optical properties with strong reverse saturable absorption (RSA), especially when 560 nm excitation laser was used. Their nonlinear optical properties followed this trend: H2TPrOPhOPc > CoTPrOPhOPc > MnTPrOPhOPc. According to the trend observed, the H2TPrOPhOPc was an excellent nonlinear optical limiter when compared to the CoTPrOPhOPc and MnTPrOPhOPc. All the investigated complexes exhibited optical limiting properties comparable to the phthalocyanine complexes reported in the literature. The MTPrOPhOPc complexes were further studied for their electrocatalytic and electroanalytical properties towards the detection of hydrogen peroxide. For the electrocatalytic studies, the synthesized complexes were immobilized onto gold electrode surfaces pre-functionalized with phenylazide (Au-PAz) monolayer. Copper (I) catalyzed alkynyl-azide cycloaddition reaction was used to covalently immobilize the MTPrOPhOPcs onto the gold electrode surfaces to form Au-PAz-MTPrOPhOPc. The MTPrOPhOPcs modified gold surfaces (Au-PAz-MTPrOPhOPc) exhibited good reproducibility and stability in various electrolyte conditions. Electrochemical and surface characterisation of the functionalised gold electrode surfaces confirmed the presence of the MTPrOPhOPcs and their electroanalysis was excellent towards electrocatalytic reduction of H2O2, with the limit of detection (LoD) and limit of quantification (LoQ) in the ^M range. The electrocatalytic reduction peaks for H2O2 were observed at -0.37 V for Au-PAz-MnTPrOPhOPc and -0.31 V for Au-PAz-CoTPrOPhOPc when Ag|AgCl pseudo-reference electrode was used. The Au-PAz-MnTPrOPhOPc and Au- PAz-CoTPrOPhOPc gold electrode surfaces showed good sensitivity and reproducibility towards the electrocatalytic reduction of hydrogen peroxide in pH 7.4 phosphate buffer solution. , Thesis (MSc) -- Faculty of Science, Chemistry, 2017
- Full Text:
- Date Issued: 2017
Molecular characterization, antibiograms and activity of medicinal plants against streptococcus pneumoniae and haemophilus influenzae isolates from clinical samples of patients in the Eastern Cape province, South Africa
- Authors: Morobe, Isaac Christopher
- Date: 2015-00
- Subjects: Medicinal plants
- Language: English
- Type: Master's/Doctoral theses , text
- Identifier: http://hdl.handle.net/11260/6469 , vital:46340
- Description: H. influenzae and S. pneumoniae are important causes of community acquired respiratory tract infections including, pneumonia, acute sinusitis, otitis media, meningitis, bacteremia, sepsis, osteomyelitis, pericarditis, septic arthritis, endocarditis, peritonitis, cellulitis and brain abscesses. The ability to effectively treat bacterial infections has been compromised in recent years due to the acquisition of antibiotic resistance, particularly to β-lactam drugs. The increasing trends in antibiotic resistance have prompted incessant searches aimed at unraveling new effective sources for the management of microbial infections. Plant derived antimicrobial compounds that have no or minimal toxicity to host cells are considered candidates for developing new antimicrobial drugs. Safety is therefore critical in the development and formulation of such antimicrobials. In addition to studies on the structural elucidation of active compounds of selected medicinal plants and determination of their toxicity levels, concerted investigations on the molecular landscape of the designated bacteria, including genes coding for resistance and virulence, the phylogenetic profiles of isolates from different sources and the abilities of isolates to withstand the normal bactericidal activities of human serum samples from different blood groups are critical for a thorough understanding of the management, pathogenetic and clinico- epidemiological trajectories of the pathogens. Therefore, the aims of the various studies were to characterize local H. influenzae and S. pneumoniae isolates by serological and molecular methods; ascertain the antibiotic susceptibility profiles of isolates in order to provide updated data and guide clinicians and other health care workers on the empiric management of patients; determine genes coding for virulence and phylogenetic relatedness of isolates of H. influenzae and S. pneumoniae from diverse sources; ascertain the bactericidal activity of human serum samples from different blood groups against H. influenzae and S. pneumoniae and also to determine the activity of active compounds and toxicity levels of selected medicinal plants. In order to achieve these goals, relevant samples were collected and screened using an array of microbiological, serological, molecular and phytochemical methods, which would be espoused in the relevant chapters, presented hereunder. Key findings of the various chapters including their contributions to knowledge are highlighted. The studies are presented in eight chapters and each chapter, with the exception of chapter one (General Introduction and Literature Review) consists of an introduction, materials and methods, results, discussions, conclusions and references. Each chapter is therefore designed as a publishable unit. Chapter 1 gives an account of the background to the study and the literature review. The morphology, cultural characteristics, laboratory diagnosis, pathogenesis, antibiogram and clinical manifestations of H. influenzae and S. pneumoniae were reviewed. Furthermore, the activities of medicinal plants and their various applications in the management of infections in different countries, including their possible active compounds and toxicity levels were also explored in order to provide a suitable background for the study. Similar reviews were undertaken for molecular aspects of both pathogens as well as the activities of human serum samples against microbial infections. In Chapter 2 the prevalence and antibiotic resistance profiles of H. influenzae and, S. pneumoniae isolates from clinical samples of patients in Mthatha, Eastern Cape Province were investigated. Clinical samples were obtained randomly from individuals attending different hospitals in Mthatha district. Samples were analysed using the Kirby Bauer disk diffusion test (antibiotic susceptibility testing) and MIC breakpoints were determined using E-test strips. From a total of 475 clinical samples tested, 323 (68.0%) were positive for both H. influenzae and S. pneumoniae. Most of the positive isolates were obtained from children under 9 years. Out of 323 isolates, 187 (57.89%) were positive for H. influenzae and 136 (42.1%) were positive for S. pneumoniae. From 10 hospitals selected for sampling in this study, Mthatha General Hospital recorded the highest number of isolates, 42 (25.15%) and 31 (22.79%) of H. influenzae and S. pneumoniae positive isolates respectively, followed by Nelson Mandela Academic Hospital 33 (19.76%) and 26 (19.12%) respectively while ST. Patricks 8 (4.79%) recorded the least number of isolates for H. influenzae and Khotsong 4 (2.94%) recorded the least number of isolates for S. pneumoniae. Antibiotic susceptibility tests revealed Amoxicillin (MIC50, 0.125μg/ml) and Vancomycin (MIC50,0.12μg/ml) as the most effective antibiotics against S. pneumoniae isolates and Co-amoxiclav (MIC50,0.3µg/ml) and Cefuroxime (MIC50,0.15µg/ml) against H. influenzae isolates. These data highlight the need for education and to consider predominant resistance when choosing empiric therapies to treat bacterial infections. Chapter 3 was designed to investigate the virulence factors of H. influenzae and S. pneumoniae isolates from clinical specimens of patients with respiratory tract infections in Mthatha district, the Eastern Cape Province. PCR and sequencing methods were used to verify the genetic determinants responsible for virulence in H. influenzae and S. pneumoniae strains. Results indicated that, of the 187 H. influenzae isolates studied, 26 (13.9%) were typeable, positive by genotypic determination, while 161 (86.1%) were non typeable (NTHi) strains. On the other, out of the 136 S. pneumoniae isolates 24 (17.6%) were typeable while 112 (82.4%) were non typeable strains. All isolates tested contained the metS2 gene for both H. influenzae and S. pneumoniae. The phylogenetic clusters identified by maximum-parsimony analysis were also compared to the results of 16S rRNA sequences. Twenty five percent of none typeable strains were typed by 16S rRNA sequencing. The phylogenetic tree yielded 7.7% H. influenzae similarities while S. pneumoniae yielded 25% similarities with other typeable strains. The presence of genes coding for virulence in this study suggest a significant contribution of genes encoding for virulence to antimicrobial resistance among respiratory tract organisms studied. This study underlines the importance of understanding the virulence composition and diversity of pathogens for enhanced clinico-epidemiological monitoring and health care delivery. The findings will also provide a genetic foundation for future research into mechanisms of pathogenesis of H. influenzae and S. pneumoniae and may accelerate the development of safe and effective vaccines to prevent and control diseases caused by H. influenzae and S. pneumoniae. In Chapter 4, cytotoxic effects and safety profiles of extracts of active medicinal plants from the OR Tambo District Municipality in the Eastern Cape of South Africa were carried out. The most prominent families of medicinal plants (Solanacea and Euphorbiaceae) were used. Extracts of nine South African medicinal plants were screened for cytotoxic activities against MAGI CC5+ cells using MTT assay. Results indicated that nine plant extracts (methanolic and aqueous) used in the MTT assay revealed Herb 2 (Cyanthula inculata) as the most potent extract identified with activity of 1.4 Cc50 values of 25.6 mg/mL and induced over 50% of cell deaths, followed by herb 3 (Croton grattismus) and Herb 4 (Cassine trasvaalensis) with activity of 0.2 Cc50 values of 3.7 mg/mL each. The herbs that induced the least cell death, were herbs 5 (Capris tomentosa) and 7 (Hypoxis hemerocallidea), with the activity of 0.05 Cc50 values of 0.9 mg/mL each. Of the nine plant extracts 2(22%) exhibited minimal toxicity on MAGI cells and 7(77.8%) exhibited 50% toxicity. Two (22%) of the methanolic extracts exhibited anti-HIV1 IIIB activities and against Mycobacterium tuberculosis (TB) only one medicinal plant extract (Lysium inerme) exhibited 29% activity. Cytotoxicity tests will provide comprehensive reference data bases for the profiling and eventual considerations of medicinal plants as potential templates for drug designs and medical applications. In chapter 5 Chemical Components of the volatile and non-volatile extractives of Croton species and their microbial activities were screened. Isolation of the essential oils from the leaves of Croton pseudopulchellus and C. gratissimus from the Eastern Cape and KwaZulu-Natal Provinces in South Africa were performed using an all glass Clevenger apparatus according to the British Pharmacopeia method. The minimum inhibitory concentrations of the oils were assessed against the seven different standard strains of bacteria: H. influenzae, Bacillus pimitus, Staphylococcus aureus, S. pneumoniae, Escherichia coli, Klebsiella pneumoniae, Serratia marcescens and Entarobacter cloacae using micro dilution technique on a 96 well microtitre plate. Results showed golden to very light yellow oils obtained with percentage yield of 1.03 -1.25 respectively (w/w). Analysis of the oils was performed using Gas Chromatography and Gas Chromatography/Mass Spectrophotometry. The leaf oil of Croton pseudopulchellus had germacrene (24.2%),β-phellandrene (17.4%), myrcene (13.4%) and β-caryophyllene (11.4%) as the prominent compounds identified in the oil. The chemical composition of the leaf oil of C. gratissimus was characterized by sabinene (14.6%), β-phellandrene (12.3%), α-phellandrene (10.7%), α-pinene (6.0%) and germacrene D (5.9%). Chemical profiles of the essential oils of Croton species reported in literatures are specific to their geographical location. The oils from C. pseudopulchellus and C. grattisimus were found to have significant antibacterial activities and therefore could be used as natural antimicrobial agents for the treatment of several infectious diseases caused by pathogenic and antibiotic resistant organisms. Chapters 6 and 7 were designed to isolate two bioactive compounds from the stem bark of Lycium inerme and the leaves of Croton grattisimus and were screened for their biological activities against H. influenzae and S. pneumoniae. A qualitative phytochemical screening and bioassay of the plants extracts was carried out. Antimicrobial screening was by broth microdilution and bioautography. Bioassay results showed that compounds with Rf –values between 0.67 to 0.80 were very active against H. influenzae and S. pneumoniae. However, the most active of these compounds was observed at 0.70 for H. influenzae and 0.69 for S. pneumoniae from the dichloromethane extract. Column chromatography, Preparative Thin Layer Chromatography (PTLC) and Sephadex LH20 were used for isolation, sample clean-up and purification of this extract. Two active compounds: a coumarin (7-hydroxy-6-methoxy-coumarin) and two triterpenoids, Ursolic acid (3-oxo-19-hydroxyl-6-methoxylpomolic acid) and Moronic acid (3-oxoolean-12-en-28-oic acid) were isolated from the dichloromethane fraction. The presence of Coumarins and Terpenoids in this herb was observed from the TLC fingerprints. NMR spectroscopic methods were used for the structural elucidation of the active compounds while the GC-MS was used to determine the presence of essential oils from volatile samples obtained from the leaves of C. grattisimus and L. inerme. C. grattisimus extracts possess strong free radicals with scavenging, antimicrobial and antifungal activities; therefore, further studies are needed to determine their efficacies in vivo or clinical usefulness. L. inerme stem bark can therefore be used as a source of alternative medicine or new pharmaceutical and health care product or as a starting material for synthesis of drugs. In chapter 8, general conclusions and perspectives of various parts of the findings were captured. The multi-drug resistance was observed among the emerging respiratory tract bacterial pathogens. It was recommended that measures should be put in place to control the spread of drug resistance in pathogens through improved and standardized laboratory practices, proper and regular surveillance to help guide against the indiscriminate use of antibiotics in empirical treatment. The recognition but cautious use of medicinal plants as alternative sources of therapies and a probable means to solve the emerging resistance problem was recommended. Improved standard of hygiene in hospital settings and the communities is important to prevent the spread of infections. The thesis provides a novel reference document on the genes coding for resistance, antibiograms and phylogenetic profiles of local isolates of H. influenzae and S. pneumoniae as well as the activities, active compounds and toxicity levels of medicinal plants investigated in an endeavour to effectively understand the possible therapeutic, molecular and epidemiological trends in respect of the designated pathogens. , Thesis (Phd) -- Faculty of Health Sciences, 2015
- Full Text:
- Date Issued: 2015-00
- Authors: Morobe, Isaac Christopher
- Date: 2015-00
- Subjects: Medicinal plants
- Language: English
- Type: Master's/Doctoral theses , text
- Identifier: http://hdl.handle.net/11260/6469 , vital:46340
- Description: H. influenzae and S. pneumoniae are important causes of community acquired respiratory tract infections including, pneumonia, acute sinusitis, otitis media, meningitis, bacteremia, sepsis, osteomyelitis, pericarditis, septic arthritis, endocarditis, peritonitis, cellulitis and brain abscesses. The ability to effectively treat bacterial infections has been compromised in recent years due to the acquisition of antibiotic resistance, particularly to β-lactam drugs. The increasing trends in antibiotic resistance have prompted incessant searches aimed at unraveling new effective sources for the management of microbial infections. Plant derived antimicrobial compounds that have no or minimal toxicity to host cells are considered candidates for developing new antimicrobial drugs. Safety is therefore critical in the development and formulation of such antimicrobials. In addition to studies on the structural elucidation of active compounds of selected medicinal plants and determination of their toxicity levels, concerted investigations on the molecular landscape of the designated bacteria, including genes coding for resistance and virulence, the phylogenetic profiles of isolates from different sources and the abilities of isolates to withstand the normal bactericidal activities of human serum samples from different blood groups are critical for a thorough understanding of the management, pathogenetic and clinico- epidemiological trajectories of the pathogens. Therefore, the aims of the various studies were to characterize local H. influenzae and S. pneumoniae isolates by serological and molecular methods; ascertain the antibiotic susceptibility profiles of isolates in order to provide updated data and guide clinicians and other health care workers on the empiric management of patients; determine genes coding for virulence and phylogenetic relatedness of isolates of H. influenzae and S. pneumoniae from diverse sources; ascertain the bactericidal activity of human serum samples from different blood groups against H. influenzae and S. pneumoniae and also to determine the activity of active compounds and toxicity levels of selected medicinal plants. In order to achieve these goals, relevant samples were collected and screened using an array of microbiological, serological, molecular and phytochemical methods, which would be espoused in the relevant chapters, presented hereunder. Key findings of the various chapters including their contributions to knowledge are highlighted. The studies are presented in eight chapters and each chapter, with the exception of chapter one (General Introduction and Literature Review) consists of an introduction, materials and methods, results, discussions, conclusions and references. Each chapter is therefore designed as a publishable unit. Chapter 1 gives an account of the background to the study and the literature review. The morphology, cultural characteristics, laboratory diagnosis, pathogenesis, antibiogram and clinical manifestations of H. influenzae and S. pneumoniae were reviewed. Furthermore, the activities of medicinal plants and their various applications in the management of infections in different countries, including their possible active compounds and toxicity levels were also explored in order to provide a suitable background for the study. Similar reviews were undertaken for molecular aspects of both pathogens as well as the activities of human serum samples against microbial infections. In Chapter 2 the prevalence and antibiotic resistance profiles of H. influenzae and, S. pneumoniae isolates from clinical samples of patients in Mthatha, Eastern Cape Province were investigated. Clinical samples were obtained randomly from individuals attending different hospitals in Mthatha district. Samples were analysed using the Kirby Bauer disk diffusion test (antibiotic susceptibility testing) and MIC breakpoints were determined using E-test strips. From a total of 475 clinical samples tested, 323 (68.0%) were positive for both H. influenzae and S. pneumoniae. Most of the positive isolates were obtained from children under 9 years. Out of 323 isolates, 187 (57.89%) were positive for H. influenzae and 136 (42.1%) were positive for S. pneumoniae. From 10 hospitals selected for sampling in this study, Mthatha General Hospital recorded the highest number of isolates, 42 (25.15%) and 31 (22.79%) of H. influenzae and S. pneumoniae positive isolates respectively, followed by Nelson Mandela Academic Hospital 33 (19.76%) and 26 (19.12%) respectively while ST. Patricks 8 (4.79%) recorded the least number of isolates for H. influenzae and Khotsong 4 (2.94%) recorded the least number of isolates for S. pneumoniae. Antibiotic susceptibility tests revealed Amoxicillin (MIC50, 0.125μg/ml) and Vancomycin (MIC50,0.12μg/ml) as the most effective antibiotics against S. pneumoniae isolates and Co-amoxiclav (MIC50,0.3µg/ml) and Cefuroxime (MIC50,0.15µg/ml) against H. influenzae isolates. These data highlight the need for education and to consider predominant resistance when choosing empiric therapies to treat bacterial infections. Chapter 3 was designed to investigate the virulence factors of H. influenzae and S. pneumoniae isolates from clinical specimens of patients with respiratory tract infections in Mthatha district, the Eastern Cape Province. PCR and sequencing methods were used to verify the genetic determinants responsible for virulence in H. influenzae and S. pneumoniae strains. Results indicated that, of the 187 H. influenzae isolates studied, 26 (13.9%) were typeable, positive by genotypic determination, while 161 (86.1%) were non typeable (NTHi) strains. On the other, out of the 136 S. pneumoniae isolates 24 (17.6%) were typeable while 112 (82.4%) were non typeable strains. All isolates tested contained the metS2 gene for both H. influenzae and S. pneumoniae. The phylogenetic clusters identified by maximum-parsimony analysis were also compared to the results of 16S rRNA sequences. Twenty five percent of none typeable strains were typed by 16S rRNA sequencing. The phylogenetic tree yielded 7.7% H. influenzae similarities while S. pneumoniae yielded 25% similarities with other typeable strains. The presence of genes coding for virulence in this study suggest a significant contribution of genes encoding for virulence to antimicrobial resistance among respiratory tract organisms studied. This study underlines the importance of understanding the virulence composition and diversity of pathogens for enhanced clinico-epidemiological monitoring and health care delivery. The findings will also provide a genetic foundation for future research into mechanisms of pathogenesis of H. influenzae and S. pneumoniae and may accelerate the development of safe and effective vaccines to prevent and control diseases caused by H. influenzae and S. pneumoniae. In Chapter 4, cytotoxic effects and safety profiles of extracts of active medicinal plants from the OR Tambo District Municipality in the Eastern Cape of South Africa were carried out. The most prominent families of medicinal plants (Solanacea and Euphorbiaceae) were used. Extracts of nine South African medicinal plants were screened for cytotoxic activities against MAGI CC5+ cells using MTT assay. Results indicated that nine plant extracts (methanolic and aqueous) used in the MTT assay revealed Herb 2 (Cyanthula inculata) as the most potent extract identified with activity of 1.4 Cc50 values of 25.6 mg/mL and induced over 50% of cell deaths, followed by herb 3 (Croton grattismus) and Herb 4 (Cassine trasvaalensis) with activity of 0.2 Cc50 values of 3.7 mg/mL each. The herbs that induced the least cell death, were herbs 5 (Capris tomentosa) and 7 (Hypoxis hemerocallidea), with the activity of 0.05 Cc50 values of 0.9 mg/mL each. Of the nine plant extracts 2(22%) exhibited minimal toxicity on MAGI cells and 7(77.8%) exhibited 50% toxicity. Two (22%) of the methanolic extracts exhibited anti-HIV1 IIIB activities and against Mycobacterium tuberculosis (TB) only one medicinal plant extract (Lysium inerme) exhibited 29% activity. Cytotoxicity tests will provide comprehensive reference data bases for the profiling and eventual considerations of medicinal plants as potential templates for drug designs and medical applications. In chapter 5 Chemical Components of the volatile and non-volatile extractives of Croton species and their microbial activities were screened. Isolation of the essential oils from the leaves of Croton pseudopulchellus and C. gratissimus from the Eastern Cape and KwaZulu-Natal Provinces in South Africa were performed using an all glass Clevenger apparatus according to the British Pharmacopeia method. The minimum inhibitory concentrations of the oils were assessed against the seven different standard strains of bacteria: H. influenzae, Bacillus pimitus, Staphylococcus aureus, S. pneumoniae, Escherichia coli, Klebsiella pneumoniae, Serratia marcescens and Entarobacter cloacae using micro dilution technique on a 96 well microtitre plate. Results showed golden to very light yellow oils obtained with percentage yield of 1.03 -1.25 respectively (w/w). Analysis of the oils was performed using Gas Chromatography and Gas Chromatography/Mass Spectrophotometry. The leaf oil of Croton pseudopulchellus had germacrene (24.2%),β-phellandrene (17.4%), myrcene (13.4%) and β-caryophyllene (11.4%) as the prominent compounds identified in the oil. The chemical composition of the leaf oil of C. gratissimus was characterized by sabinene (14.6%), β-phellandrene (12.3%), α-phellandrene (10.7%), α-pinene (6.0%) and germacrene D (5.9%). Chemical profiles of the essential oils of Croton species reported in literatures are specific to their geographical location. The oils from C. pseudopulchellus and C. grattisimus were found to have significant antibacterial activities and therefore could be used as natural antimicrobial agents for the treatment of several infectious diseases caused by pathogenic and antibiotic resistant organisms. Chapters 6 and 7 were designed to isolate two bioactive compounds from the stem bark of Lycium inerme and the leaves of Croton grattisimus and were screened for their biological activities against H. influenzae and S. pneumoniae. A qualitative phytochemical screening and bioassay of the plants extracts was carried out. Antimicrobial screening was by broth microdilution and bioautography. Bioassay results showed that compounds with Rf –values between 0.67 to 0.80 were very active against H. influenzae and S. pneumoniae. However, the most active of these compounds was observed at 0.70 for H. influenzae and 0.69 for S. pneumoniae from the dichloromethane extract. Column chromatography, Preparative Thin Layer Chromatography (PTLC) and Sephadex LH20 were used for isolation, sample clean-up and purification of this extract. Two active compounds: a coumarin (7-hydroxy-6-methoxy-coumarin) and two triterpenoids, Ursolic acid (3-oxo-19-hydroxyl-6-methoxylpomolic acid) and Moronic acid (3-oxoolean-12-en-28-oic acid) were isolated from the dichloromethane fraction. The presence of Coumarins and Terpenoids in this herb was observed from the TLC fingerprints. NMR spectroscopic methods were used for the structural elucidation of the active compounds while the GC-MS was used to determine the presence of essential oils from volatile samples obtained from the leaves of C. grattisimus and L. inerme. C. grattisimus extracts possess strong free radicals with scavenging, antimicrobial and antifungal activities; therefore, further studies are needed to determine their efficacies in vivo or clinical usefulness. L. inerme stem bark can therefore be used as a source of alternative medicine or new pharmaceutical and health care product or as a starting material for synthesis of drugs. In chapter 8, general conclusions and perspectives of various parts of the findings were captured. The multi-drug resistance was observed among the emerging respiratory tract bacterial pathogens. It was recommended that measures should be put in place to control the spread of drug resistance in pathogens through improved and standardized laboratory practices, proper and regular surveillance to help guide against the indiscriminate use of antibiotics in empirical treatment. The recognition but cautious use of medicinal plants as alternative sources of therapies and a probable means to solve the emerging resistance problem was recommended. Improved standard of hygiene in hospital settings and the communities is important to prevent the spread of infections. The thesis provides a novel reference document on the genes coding for resistance, antibiograms and phylogenetic profiles of local isolates of H. influenzae and S. pneumoniae as well as the activities, active compounds and toxicity levels of medicinal plants investigated in an endeavour to effectively understand the possible therapeutic, molecular and epidemiological trends in respect of the designated pathogens. , Thesis (Phd) -- Faculty of Health Sciences, 2015
- Full Text:
- Date Issued: 2015-00
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