Chemical analysis of selected Eastern Cape medicinal plants
- Authors: Mahanjana, Lungelwa
- Date: 2022-04
- Subjects: Medicinal plants -- South Africa --Eastern Cape , Traditional medicine --South Africa -- Eastern Cape Maps
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/55976 , vital:54560
- Description: In the rural parts of the Eastern Cape Province of South Africa, the use of medicinal plants to treat or manage diseases, including those associated with diabetes and HIV, is a common practice. However, the phytochemistry, safety and efficacy of these medicinal plants remain less investigated. Based on available traditional medicinal knowledge (through traditional healers, university library resources, ethnobotanical and science journals and other internet resources), traditional uses and availability, three plant species, namely Bulbine latifolia L. Wild, Dicerothamnus rhinocerotis Koek. and Olea europaea subsp. africana (Mill.) P.S. Green were selected and investigated for their hytoconstituents and biological effects. Phytochemical screening of the three medicinal plants was carried out quantitatively and qualitatively using spectrophotometric methods. Chemical profiling of the crude methanol extracts of all the plant species was successfully done by high-performance thin layer chromatography (HPTLC) and tentative identification of the secondary metabolites was achieved by liquid chromatography–mass spectrometry (LCMS). Cytotoxicity effect investigations on the crude extracts of the three species was done using the 3-[4,5- dimethylthiazole-2-yl]-2,5- hiphenyltetrazolium bromide (MTT) assay against HeLa cervical cancer cells. Isolation and purification of single compounds was done using chromatographic techniques (column chromatography (CC), and preparative thin-layer chromatography (PTLC)). Characterisation of single compounds was achieved using spectroscopic techniques such as Nuclear Magnetic Resonance (NMR), High Resolution Mass Spectrometry (HRMS), Ultra Violet Spectroscopy (UV-vis), Fourier-Transformed Infra-Red Spectroscopy (FTIR) and Single-Crystal X-ray Diffraction (XRD). For the first time from the methanol crude extract of the tubers of B. latifolia, the crystal structure of the phenylanthraquinone, knipholone (3.12) (1-(3-acetyl-2,6- dihydroxy-4- methoxyphenyl)-4,5-dihydroxy-2-methylanthraquinone), was isolated and elucidated along with its derivatives, isoknipholone (3.14), knipholone-6’-methyl (3.27). Moreover, two new compounds, (M)-8-O-β-D-glucopyranosyl-10’-α-L-rhamnopyranosyl-1,1',8',10'-tetrahydroxy 3,3'-dimethyl-[10,7'-bianthracene]-4,9,9'(10'H)-trione (3.23a) and (P)- 8-O-β-D glucopyranosyl-10’-α-L-rhamnopyranosyl-1,1',8',10'-tetrahydroxy-3,3'-dimethyl-[10,7'- bianthracene]-4,9,9'(10'H)-trione (3.23b) were isolated. , Thesis (PhD) -- Faculty of Science, School of Biomecular and Chemical Sciences, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Mahanjana, Lungelwa
- Date: 2022-04
- Subjects: Medicinal plants -- South Africa --Eastern Cape , Traditional medicine --South Africa -- Eastern Cape Maps
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/55976 , vital:54560
- Description: In the rural parts of the Eastern Cape Province of South Africa, the use of medicinal plants to treat or manage diseases, including those associated with diabetes and HIV, is a common practice. However, the phytochemistry, safety and efficacy of these medicinal plants remain less investigated. Based on available traditional medicinal knowledge (through traditional healers, university library resources, ethnobotanical and science journals and other internet resources), traditional uses and availability, three plant species, namely Bulbine latifolia L. Wild, Dicerothamnus rhinocerotis Koek. and Olea europaea subsp. africana (Mill.) P.S. Green were selected and investigated for their hytoconstituents and biological effects. Phytochemical screening of the three medicinal plants was carried out quantitatively and qualitatively using spectrophotometric methods. Chemical profiling of the crude methanol extracts of all the plant species was successfully done by high-performance thin layer chromatography (HPTLC) and tentative identification of the secondary metabolites was achieved by liquid chromatography–mass spectrometry (LCMS). Cytotoxicity effect investigations on the crude extracts of the three species was done using the 3-[4,5- dimethylthiazole-2-yl]-2,5- hiphenyltetrazolium bromide (MTT) assay against HeLa cervical cancer cells. Isolation and purification of single compounds was done using chromatographic techniques (column chromatography (CC), and preparative thin-layer chromatography (PTLC)). Characterisation of single compounds was achieved using spectroscopic techniques such as Nuclear Magnetic Resonance (NMR), High Resolution Mass Spectrometry (HRMS), Ultra Violet Spectroscopy (UV-vis), Fourier-Transformed Infra-Red Spectroscopy (FTIR) and Single-Crystal X-ray Diffraction (XRD). For the first time from the methanol crude extract of the tubers of B. latifolia, the crystal structure of the phenylanthraquinone, knipholone (3.12) (1-(3-acetyl-2,6- dihydroxy-4- methoxyphenyl)-4,5-dihydroxy-2-methylanthraquinone), was isolated and elucidated along with its derivatives, isoknipholone (3.14), knipholone-6’-methyl (3.27). Moreover, two new compounds, (M)-8-O-β-D-glucopyranosyl-10’-α-L-rhamnopyranosyl-1,1',8',10'-tetrahydroxy 3,3'-dimethyl-[10,7'-bianthracene]-4,9,9'(10'H)-trione (3.23a) and (P)- 8-O-β-D glucopyranosyl-10’-α-L-rhamnopyranosyl-1,1',8',10'-tetrahydroxy-3,3'-dimethyl-[10,7'- bianthracene]-4,9,9'(10'H)-trione (3.23b) were isolated. , Thesis (PhD) -- Faculty of Science, School of Biomecular and Chemical Sciences, 2022
- Full Text:
- Date Issued: 2022-04
Classification and clustering based methods for outlier detection of solar resource data
- Authors: Abrahams, Waldo
- Date: 2022-04
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/55423 , vital:51996
- Description: Almost 90% of the primary global energy demand is serviced from the burning of fossil fuels (Abas, Kalair & Khan, 2015). Owing to the detrimental environmental impact of this, a global energy transition to the use of renewable energy, including solar energy, is needed (Gielen et al., 2019). An important aspect that inhibits the growth of solar energy is accurate solar resource data. Such data is needed because knowledge of the future reliability and quality of energy production is required to analyse a system’s performance and determine financial implications (Sengupta et al., 2017). Existing methods used to detect outliers in solar resource data do not efficiently identify outliers and an accurate and robust approach is required (Eastwood, 2019). Using simulated and real-world data, this study investigates the use of several classification methods, along with a two-stage clustering-classification approach to accurately identify outliers in solar resource data. The Treebag method proves to be an adequate outlier detection method for solar resource data. , Thesis (MSc) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Abrahams, Waldo
- Date: 2022-04
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/55423 , vital:51996
- Description: Almost 90% of the primary global energy demand is serviced from the burning of fossil fuels (Abas, Kalair & Khan, 2015). Owing to the detrimental environmental impact of this, a global energy transition to the use of renewable energy, including solar energy, is needed (Gielen et al., 2019). An important aspect that inhibits the growth of solar energy is accurate solar resource data. Such data is needed because knowledge of the future reliability and quality of energy production is required to analyse a system’s performance and determine financial implications (Sengupta et al., 2017). Existing methods used to detect outliers in solar resource data do not efficiently identify outliers and an accurate and robust approach is required (Eastwood, 2019). Using simulated and real-world data, this study investigates the use of several classification methods, along with a two-stage clustering-classification approach to accurately identify outliers in solar resource data. The Treebag method proves to be an adequate outlier detection method for solar resource data. , Thesis (MSc) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2022
- Full Text:
- Date Issued: 2022-04
Climate Change and Rural Livelihoods: A Case of Insiza District, Matabeleland
- Authors: Nyoni, Sibusisiwe Ruth
- Date: 2022-04
- Subjects: Climatic change -- Zimbabwe
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/58112 , vital:58579
- Description: Owen Jones’ famous article “Why don’t we treat climate change with the same urgency as Coronavirus” puts forward an intriguing dimension to the climate change phenomenon. Despite the threat it presents to millions of people as well as the world economy, little has been done to prevent countries from being overwhelmed by its effects. Due to the fact that climate change is happening now, the purpose of this study provides insight into climate change and rural livelihoods in Insiza district, Matabeleland. In this study, an interpretivist paradigm was adopted as it gave the researcher adequate information that embodies an account of the participants’ understanding of livelihood assets. The qualitative research approach was adopted as it allowed the researcher to classify the findings into broad themes in order to tell a story. Farmers in Insiza district who depend on agriculture for subsistence were interviewed to provide insight into this phenomenon. The findings of the study revealed that climate stresses, non-climate stresses as well as institutional constraints together contribute to the vulnerability of farmers. Additionally, the findings unveiled that the inconsistent weather patterns as well as the recurrent droughts in the area have pushed most farmers to find alternative means of livelihood. Therefore, farmers over time have resorted to other self-taught means of making a living such as building, small scale mining, buying and selling of clothing items, running grocery stores, baking, owning backyard vegetable gardens, welding, fishing, selling firewood and growing chickens for sale. On the same note the findings showed that farmers in Insiza district employ different coping strategies in attempting to deal with climate change. The most common method in the area of study is conservation farming which has to do with digging pits to store water. More so, the findings displayed that NGOs have been of great assistance in equipping farmers at such a time as this. The study recommends that the government needs to ensure financial and institutional mechanisms to assist the Insiza community. Also, the NGOs must continue to support the communities through equipping them to diversify their portfolios and through developing tailor made capacity building programmes. To the farmers it is recommended that they continue to move in unity and form relationships with other farmers from other districts and provinces so that they can continue to share information. , Thesis (MA) -- Faculty of Business and Economic science, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Nyoni, Sibusisiwe Ruth
- Date: 2022-04
- Subjects: Climatic change -- Zimbabwe
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/58112 , vital:58579
- Description: Owen Jones’ famous article “Why don’t we treat climate change with the same urgency as Coronavirus” puts forward an intriguing dimension to the climate change phenomenon. Despite the threat it presents to millions of people as well as the world economy, little has been done to prevent countries from being overwhelmed by its effects. Due to the fact that climate change is happening now, the purpose of this study provides insight into climate change and rural livelihoods in Insiza district, Matabeleland. In this study, an interpretivist paradigm was adopted as it gave the researcher adequate information that embodies an account of the participants’ understanding of livelihood assets. The qualitative research approach was adopted as it allowed the researcher to classify the findings into broad themes in order to tell a story. Farmers in Insiza district who depend on agriculture for subsistence were interviewed to provide insight into this phenomenon. The findings of the study revealed that climate stresses, non-climate stresses as well as institutional constraints together contribute to the vulnerability of farmers. Additionally, the findings unveiled that the inconsistent weather patterns as well as the recurrent droughts in the area have pushed most farmers to find alternative means of livelihood. Therefore, farmers over time have resorted to other self-taught means of making a living such as building, small scale mining, buying and selling of clothing items, running grocery stores, baking, owning backyard vegetable gardens, welding, fishing, selling firewood and growing chickens for sale. On the same note the findings showed that farmers in Insiza district employ different coping strategies in attempting to deal with climate change. The most common method in the area of study is conservation farming which has to do with digging pits to store water. More so, the findings displayed that NGOs have been of great assistance in equipping farmers at such a time as this. The study recommends that the government needs to ensure financial and institutional mechanisms to assist the Insiza community. Also, the NGOs must continue to support the communities through equipping them to diversify their portfolios and through developing tailor made capacity building programmes. To the farmers it is recommended that they continue to move in unity and form relationships with other farmers from other districts and provinces so that they can continue to share information. , Thesis (MA) -- Faculty of Business and Economic science, 2022
- Full Text:
- Date Issued: 2022-04
Combined Additive Manufacturing and Machining for Large-Scale Prototyping for Minimising Material Wastage
- Authors: Taylor, Kyle Joshua
- Date: 2022-04
- Subjects: Prototypes, Engineering
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/58484 , vital:59645
- Description: This research project aimed to develop a combined additive and subtractive manufacturing platform capable of rapidly producing large-scale prototypes for minimising material wastage. A design conceptualisation process led to the design and development of a system to deposit the additive material. The developed system was mounted to a large-scale CNC milling machine. This combination of additive and subtractive manufacturing into a single system integrated the separate benefits of the two independent technologies. Mastercam was selected as the preferred CAD/CAM software package to generate toolpaths for the additive and subtractive processes. The Beckhoff HMI provided a user-friendly interface to interpret the generated G-code files, set the Work Coordinate System, and control user-defined parameters such as the feed rate. An in-depth statistical analysis of the developed platform's dimensional accuracy, repeatability, stability, and material wastage was performed. In addition, the effects of the independent adjustment of the subtractive manufacturing process parameters such as the spindle speed, feed rate, depth of cut and stepover distance were considered. Finally, a cycle time comparison was performed in producing a working prototype between the developed HM system and a commercially available 3D printer. This research provided a platform for further investigation into the ever-expanding applications and benefits of rapid prototyping. , Thesis (MA) -- Faculty of Engineering, the Built Environment, and Technology, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Taylor, Kyle Joshua
- Date: 2022-04
- Subjects: Prototypes, Engineering
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/58484 , vital:59645
- Description: This research project aimed to develop a combined additive and subtractive manufacturing platform capable of rapidly producing large-scale prototypes for minimising material wastage. A design conceptualisation process led to the design and development of a system to deposit the additive material. The developed system was mounted to a large-scale CNC milling machine. This combination of additive and subtractive manufacturing into a single system integrated the separate benefits of the two independent technologies. Mastercam was selected as the preferred CAD/CAM software package to generate toolpaths for the additive and subtractive processes. The Beckhoff HMI provided a user-friendly interface to interpret the generated G-code files, set the Work Coordinate System, and control user-defined parameters such as the feed rate. An in-depth statistical analysis of the developed platform's dimensional accuracy, repeatability, stability, and material wastage was performed. In addition, the effects of the independent adjustment of the subtractive manufacturing process parameters such as the spindle speed, feed rate, depth of cut and stepover distance were considered. Finally, a cycle time comparison was performed in producing a working prototype between the developed HM system and a commercially available 3D printer. This research provided a platform for further investigation into the ever-expanding applications and benefits of rapid prototyping. , Thesis (MA) -- Faculty of Engineering, the Built Environment, and Technology, 2022
- Full Text:
- Date Issued: 2022-04
Composition portfolio
- Authors: Lemmer, Elizabeth Kate
- Date: 2022-04
- Subjects: Composition (Music) , Music South Africa , COVID-19 (Disease) and the arts , Emotions in music , Violin music Scores , String quartets Scores , Chamber music Scores
- Language: English
- Type: Master's thesis , text , sheet music
- Identifier: http://hdl.handle.net/10962/232624 , vital:50008
- Description: In this portfolio I reflect on issues Covid-19 has brought to our communities and the possibilities of creating a brighter future. My music reflects the struggle that most people have faced in the last two years, the emotions and the conspiracies surrounding the experience, and the effect of solitude. In a time such as this it is almost inevitable that the music being composed is connected to the struggle in society at large. For ma composition is a journal of the heart. The pandemic has created a situation where most are out of touch with each other, have lost all previous routine and structure, where relationships are broken due to lack of personal contact, and almost everyone has unwillingly (or unwittingly) been thrust into self-reflection. Every day sees a new struggle to squeeze in all those pre-pandemic ideals so that some normalcy can be obtained, but this is not a time to be looking back. It’s a time to understand what we are going through, build new joy and excitement for this different life and learn to live the best we can with the opportunities we are given. There has not been a more important time to foster some form of connection with friends and family, and to be as strong and supportive as possible. The portfolio begins with a solo violin piece, Unwelcome Solitude, which exemplifies the loneliness and sadness during the various lockdowns over the last two years, with hints of the past and the difficulties in trying to resurrect pre-Covid-19 times. There are some unusual expressive markings to add to the descriptive effect within the piece. This is followed by The Pandemic, two serialism works: Panic and Pain scored for a string quartet. Both of these pieces apply a flexible use of serialism to emphasize out the emotional aspects of the music, and quite simply; the panic and the pain caused by Covid-19 and the country’s response to the pandemic as a whole. Finally there is a three movement chamber piece titled A Storm Series which quite literally represents the series of events that occur from the upcoming to the closure of a typical Highveld storm. Further than this, these pieces represent the series of events that occurred in South Africa from the first rumour of the Covid-19 virus starting to circle around the world, through the various lockdowns and progression of events in our country and abroad. The final movement of this series, Re-awakening, ends on a positive note representing the rainbow at the end of the storm, and the positive outlook for South Africa to keep persevering through the pandemic. , Thesis (MMus) -- Faculty of Humanities, Music and Musicology, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Lemmer, Elizabeth Kate
- Date: 2022-04
- Subjects: Composition (Music) , Music South Africa , COVID-19 (Disease) and the arts , Emotions in music , Violin music Scores , String quartets Scores , Chamber music Scores
- Language: English
- Type: Master's thesis , text , sheet music
- Identifier: http://hdl.handle.net/10962/232624 , vital:50008
- Description: In this portfolio I reflect on issues Covid-19 has brought to our communities and the possibilities of creating a brighter future. My music reflects the struggle that most people have faced in the last two years, the emotions and the conspiracies surrounding the experience, and the effect of solitude. In a time such as this it is almost inevitable that the music being composed is connected to the struggle in society at large. For ma composition is a journal of the heart. The pandemic has created a situation where most are out of touch with each other, have lost all previous routine and structure, where relationships are broken due to lack of personal contact, and almost everyone has unwillingly (or unwittingly) been thrust into self-reflection. Every day sees a new struggle to squeeze in all those pre-pandemic ideals so that some normalcy can be obtained, but this is not a time to be looking back. It’s a time to understand what we are going through, build new joy and excitement for this different life and learn to live the best we can with the opportunities we are given. There has not been a more important time to foster some form of connection with friends and family, and to be as strong and supportive as possible. The portfolio begins with a solo violin piece, Unwelcome Solitude, which exemplifies the loneliness and sadness during the various lockdowns over the last two years, with hints of the past and the difficulties in trying to resurrect pre-Covid-19 times. There are some unusual expressive markings to add to the descriptive effect within the piece. This is followed by The Pandemic, two serialism works: Panic and Pain scored for a string quartet. Both of these pieces apply a flexible use of serialism to emphasize out the emotional aspects of the music, and quite simply; the panic and the pain caused by Covid-19 and the country’s response to the pandemic as a whole. Finally there is a three movement chamber piece titled A Storm Series which quite literally represents the series of events that occur from the upcoming to the closure of a typical Highveld storm. Further than this, these pieces represent the series of events that occurred in South Africa from the first rumour of the Covid-19 virus starting to circle around the world, through the various lockdowns and progression of events in our country and abroad. The final movement of this series, Re-awakening, ends on a positive note representing the rainbow at the end of the storm, and the positive outlook for South Africa to keep persevering through the pandemic. , Thesis (MMus) -- Faculty of Humanities, Music and Musicology, 2022
- Full Text:
- Date Issued: 2022-04
Constructing an online serviceScape for the funeral industry
- Authors: Coetzee, Cornelis Albertus
- Date: 2022-04
- Subjects: Funeral supplies industry , Funeral service , Service industries -- Marketing
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/57611 , vital:58186
- Description: An online servicescape serves as a moderator for excellence in Customer Relationship Management (CRM). The study approached the online servicescape from the perspective of the funeral industry. Nowhere is the relevance of an online servicescape more apparent than in an industry which is firstly, unsought, and secondly, perceived as dismal. During the process of arranging a funeral, the customer is experiencing an unusual purchase situation as it is a purchase that cannot be avoided. The possibility also exists that the customer most likely did not seek information about a funeral home prior to the demise of a loved one. A third contributing factor is the emotional state of the customer which will, in a time of bereavement, have a strong impact on the rational decision-making process. Considering these conditions, the study approached the online servicescape based on three elements, namely Search Engine Optimisation, perceived value, and perceived usefulness of the online servicescape. These elements contribute to trust in the funeral home’s online offerings, which could influence the purchase outcomes significantly. The aim of the study was to construct a functional servicescape for an unsought business such as a funeral home, hence contributing significantly to the CRM body of knowledge as it was determined that this has not been explored before from an academic perspective. A quantitative, exploratory methodology was implemented. The exploration is depended on Bitner's (1992a:60) seminal model of servicescapes, Harris and Goode's (2010:230-243) model for online servicescapes, and the key constructs of Simon's (1996:141-142) Design Theory to provide a methodological basis with which to construct the key elements for a funeral industry based online servicescape. The data collection process followed a twostep process. A content analysis was conducted on existing websites from five English speaking countries, followed by a survey that largely reflected the content analysis variables to gain customer insights. The data was analysed using a descriptive analysis process. v It was determined that customers would trust a functional servicescape, which will most probably lead to a purchase situation. However, customers also indicated the opposite if they detect anything on the website that might lead to distrust. It was therefore concluded that it is imperative for a funeral home to ensure that their online servicescape meets the functional needs of customers in order ensure trust and purchase intention. , Thesis (PhD) -- Faculty of Business and Economic science, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Coetzee, Cornelis Albertus
- Date: 2022-04
- Subjects: Funeral supplies industry , Funeral service , Service industries -- Marketing
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/57611 , vital:58186
- Description: An online servicescape serves as a moderator for excellence in Customer Relationship Management (CRM). The study approached the online servicescape from the perspective of the funeral industry. Nowhere is the relevance of an online servicescape more apparent than in an industry which is firstly, unsought, and secondly, perceived as dismal. During the process of arranging a funeral, the customer is experiencing an unusual purchase situation as it is a purchase that cannot be avoided. The possibility also exists that the customer most likely did not seek information about a funeral home prior to the demise of a loved one. A third contributing factor is the emotional state of the customer which will, in a time of bereavement, have a strong impact on the rational decision-making process. Considering these conditions, the study approached the online servicescape based on three elements, namely Search Engine Optimisation, perceived value, and perceived usefulness of the online servicescape. These elements contribute to trust in the funeral home’s online offerings, which could influence the purchase outcomes significantly. The aim of the study was to construct a functional servicescape for an unsought business such as a funeral home, hence contributing significantly to the CRM body of knowledge as it was determined that this has not been explored before from an academic perspective. A quantitative, exploratory methodology was implemented. The exploration is depended on Bitner's (1992a:60) seminal model of servicescapes, Harris and Goode's (2010:230-243) model for online servicescapes, and the key constructs of Simon's (1996:141-142) Design Theory to provide a methodological basis with which to construct the key elements for a funeral industry based online servicescape. The data collection process followed a twostep process. A content analysis was conducted on existing websites from five English speaking countries, followed by a survey that largely reflected the content analysis variables to gain customer insights. The data was analysed using a descriptive analysis process. v It was determined that customers would trust a functional servicescape, which will most probably lead to a purchase situation. However, customers also indicated the opposite if they detect anything on the website that might lead to distrust. It was therefore concluded that it is imperative for a funeral home to ensure that their online servicescape meets the functional needs of customers in order ensure trust and purchase intention. , Thesis (PhD) -- Faculty of Business and Economic science, 2022
- Full Text:
- Date Issued: 2022-04
Credit risk management impact on loan performance in development finance institutions in South Africa
- Lekhelebana, Letlatsa George
- Authors: Lekhelebana, Letlatsa George
- Date: 2022-04
- Subjects: Development finance institutions , Credit -- Management -- South Africa
- Language: English
- Type: Doctoral's theses , text
- Identifier: http://hdl.handle.net/10948/57698 , vital:58217
- Description: Development Finance Institutions ( play an important role in being a catalyst for economic development and growth where they operate. TUHF Group operates as a niche commercial property D FI funding entrepreneurs that seek to bring to market properties that deliver multi let housing units. This also deals with the pro blem of the lack of housing that South Africa has. For DFIs to operate optimally and be financially sustainable , they need to source funding from either shareholders or the financial markets. Financial markets require that the DFIs operate in a profitable manner to qualify for funding and this is also driven by the way the DFI manages the loan book’s integrity. This study examines the relationship between credit risk management policy, processes and procedures in practice and the TUHF Group and their impa ct on the performance of the loan book. In order that the research aim and objectives are fulfilled, and the research question answered, the study undertook an extensive review of existing literature on DFIs, the impact on economic development and growt h, the impact of badly performing loan books on the performance of companies and how this is impacted on by credit management structures, policies and procedures. An empirical study was conducted through the collection of primary data from the internal doc uments at TUHF Group and among some of the staff members at TUHF through a structured interviews based on open ended questions. The research revealed that there is indeed a link between the credit risk management processes and procedures at TUHF and the performance of the loan book, the findings indicated that the current policy and procedures is not sufficient for a well performing loan book and the pr imary data showed worsening performance of the loan book over time. These findings further indicate a requirement for TUHF to improve the credit policies and architecture for a sustainable financial performance in future. , Thesis (MA) -- Faculty of Business and Economic science, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Lekhelebana, Letlatsa George
- Date: 2022-04
- Subjects: Development finance institutions , Credit -- Management -- South Africa
- Language: English
- Type: Doctoral's theses , text
- Identifier: http://hdl.handle.net/10948/57698 , vital:58217
- Description: Development Finance Institutions ( play an important role in being a catalyst for economic development and growth where they operate. TUHF Group operates as a niche commercial property D FI funding entrepreneurs that seek to bring to market properties that deliver multi let housing units. This also deals with the pro blem of the lack of housing that South Africa has. For DFIs to operate optimally and be financially sustainable , they need to source funding from either shareholders or the financial markets. Financial markets require that the DFIs operate in a profitable manner to qualify for funding and this is also driven by the way the DFI manages the loan book’s integrity. This study examines the relationship between credit risk management policy, processes and procedures in practice and the TUHF Group and their impa ct on the performance of the loan book. In order that the research aim and objectives are fulfilled, and the research question answered, the study undertook an extensive review of existing literature on DFIs, the impact on economic development and growt h, the impact of badly performing loan books on the performance of companies and how this is impacted on by credit management structures, policies and procedures. An empirical study was conducted through the collection of primary data from the internal doc uments at TUHF Group and among some of the staff members at TUHF through a structured interviews based on open ended questions. The research revealed that there is indeed a link between the credit risk management processes and procedures at TUHF and the performance of the loan book, the findings indicated that the current policy and procedures is not sufficient for a well performing loan book and the pr imary data showed worsening performance of the loan book over time. These findings further indicate a requirement for TUHF to improve the credit policies and architecture for a sustainable financial performance in future. , Thesis (MA) -- Faculty of Business and Economic science, 2022
- Full Text:
- Date Issued: 2022-04
Design, Development and Testing of a Low-cost Sub-Joule μPPT for a PocketQube
- Authors: Bae, Ji Eun
- Date: 2022-04
- Subjects: Electric current converters , Pulse circuits , Plasma jets
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/58295 , vital:58953
- Description: Small satellites are unmanned spacecraft with small size and mass weighing less than 500kg. A small satellite called the CubeSat was created by two university professors to help students understand satellite design. The idea of small satellites caught on and they became popular due to their low cost, quick development time and easy deployment. The inexpensive nature of small satellites has helped lower the entry barrier to space and led to a movement called the “democratisation of space”. The popularity of small satellites has also caught the eye of private companies that recognise the potential of commercialising small satellite technologies. Nowadays, small satellites are being considered for more complex and challenging space missions. However for a small satellite to reach its full potential, it needs to be equipped with a proper propulsion system. Governments, space agencies, companies and universities around the world have started to research new innovative miniaturised space propulsion technologies. Nowadays, there are many newly developed miniaturised propulsion technologies available. The new propulsion systems are either sold by the companies and universities at a very high price, or research and development is closely guarded due to the potential commercial value of the propulsion system. Companies and universities have primarily focused on researching and developing top-of-the-line micro-propulsion devices to win lucrative research funds. This has resulted in a lack of research into cheap reliable micropropulsion as there have been no incentives for companies and universities to develop this area. As a result, fund-limited students and individuals have been left behind, defeating the purpose of small satellites. This dissertation focuses on designing and developing a low-cost sub-joule micro-PPT propulsion system for a PocketQube satellite. The first section covers the literature review, which looks at the different space propulsion technologies currently available. The next section covers the micro-PPT propulsion system’s mechanical and electrical design and development process. After the development process, the performance of the prototype is tested using various input parameters, as well as in vacuum conditions and over its lifetime. The test results show that the optimal performance is obtained with an input voltage supply of 5V at a pulse frequency of 0.5Hz, which achieves a minimal impulse bit v of 0.698μNs and thrust range of 0.349~1.071μN. In comparison to the STRaND-1 3U CubeSat’s PPT, performance data show that the developed μPPT propulsion system is a competitive propulsion solution, as it achieves more thrust with similar minimal impulse bit, using only one third of the power consumption. The μPPT propulsion system is able to produce 1980 shots so far, which is far lower relatively than other established PPTs due to the limitations resulting from capacitor failure. , Thesis (MA) -- Faculty of Engineering, the Built Environment, and Technology, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Bae, Ji Eun
- Date: 2022-04
- Subjects: Electric current converters , Pulse circuits , Plasma jets
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/58295 , vital:58953
- Description: Small satellites are unmanned spacecraft with small size and mass weighing less than 500kg. A small satellite called the CubeSat was created by two university professors to help students understand satellite design. The idea of small satellites caught on and they became popular due to their low cost, quick development time and easy deployment. The inexpensive nature of small satellites has helped lower the entry barrier to space and led to a movement called the “democratisation of space”. The popularity of small satellites has also caught the eye of private companies that recognise the potential of commercialising small satellite technologies. Nowadays, small satellites are being considered for more complex and challenging space missions. However for a small satellite to reach its full potential, it needs to be equipped with a proper propulsion system. Governments, space agencies, companies and universities around the world have started to research new innovative miniaturised space propulsion technologies. Nowadays, there are many newly developed miniaturised propulsion technologies available. The new propulsion systems are either sold by the companies and universities at a very high price, or research and development is closely guarded due to the potential commercial value of the propulsion system. Companies and universities have primarily focused on researching and developing top-of-the-line micro-propulsion devices to win lucrative research funds. This has resulted in a lack of research into cheap reliable micropropulsion as there have been no incentives for companies and universities to develop this area. As a result, fund-limited students and individuals have been left behind, defeating the purpose of small satellites. This dissertation focuses on designing and developing a low-cost sub-joule micro-PPT propulsion system for a PocketQube satellite. The first section covers the literature review, which looks at the different space propulsion technologies currently available. The next section covers the micro-PPT propulsion system’s mechanical and electrical design and development process. After the development process, the performance of the prototype is tested using various input parameters, as well as in vacuum conditions and over its lifetime. The test results show that the optimal performance is obtained with an input voltage supply of 5V at a pulse frequency of 0.5Hz, which achieves a minimal impulse bit v of 0.698μNs and thrust range of 0.349~1.071μN. In comparison to the STRaND-1 3U CubeSat’s PPT, performance data show that the developed μPPT propulsion system is a competitive propulsion solution, as it achieves more thrust with similar minimal impulse bit, using only one third of the power consumption. The μPPT propulsion system is able to produce 1980 shots so far, which is far lower relatively than other established PPTs due to the limitations resulting from capacitor failure. , Thesis (MA) -- Faculty of Engineering, the Built Environment, and Technology, 2022
- Full Text:
- Date Issued: 2022-04
Design, synthesis, characterization and evaluation of Chitosan-based hydrogel for controlled drug delivery system
- Authors: Safari, Justin Bazibuhe
- Date: 2022-04
- Subjects: Chitosan , Drug delivery systems , Drugs Controlled release , Tenofovir , Colloids , Hepatitis B Chemotherapy , Hydrogel
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/232182 , vital:49969
- Description: Hepatitis B infection is a deadly infectious disease caused by the hepatitis B virus and is responsible for many deaths every year worldwide. Despite medication and vaccines against hepatitis B infection, it still presents high morbidity and mortality among populations. This is partly due to factors such as a long medication period of the existing treatments, resulting in poor patient compliance and leading to treatment failure. In addition, this situation can be responsible for the observed emerging drug resistance. Hence, novel drugs and drug delivery systems are needed to tackle this matter. Many strategies have been used to develop long-acting drug delivery systems treatment for several infectious diseases. Hydrogel drug delivery systems have shown interesting results as controlled drug delivery systems for several drugs. Therefore, the present study aimed to develop chitosan grafted poly (acrylamide-co-acrylic acid) hydrogel and apply it as a pH-sensitive controlled delivery system of tenofovir disoproxil fumarate (TDF). TDF is a nucleoside reverse transcriptase inhibitor used as first-line treatment of hepatitis B chronic infection and in the treatment of other viral infections. The free-radical polymerization method was utilized to modify chitosan by grafting acrylamide and acrylic acid and using N, N’-methylene bisacrylamide as the crosslinking agent to prepare the hydrogel, followed by an optimization of parameters that could affect the swelling capacity. The prepared chitosan-g-poly(acrylamide-co-acrylic acid) hydrogel was characterized using Fourier Transmission Infra-red spectroscopy (FTIR), X-Ray Diffraction (XRD), Thermal Gravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), Energy-dispersive X-ray spectroscopy (EDS), Scanning Electron Microscopy (SEM), and was evaluated for cytotoxicity using a HeLa cell assay. TDF was used as a drug model, it was loaded by the swelling equilibrium method, following by the investigation of the release profile of TDF-loaded hydrogel at pH 1.2 and 7.4. A successful synthesis of chitosan grafted poly(acrylamide-co-acrylic acid) hydrogel was confirmed by Fourier Transmission Infra-red spectroscopy (FTIR), X-Ray Diffraction Spectroscopy (XRD), Thermal Gravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), Energy-dispersive X-ray spectroscopy (EDS) and Scanning Electron Microscopy (SEM). Optimization results showed that the ratio of monomers impacted the swelling ratio of the hydrogel and both the concentration of the crosslinking agent, and the reaction initiator also affected the swelling ratio. The synthesized hydrogels were sensitive to pH and ionic strength. Hydrogel swelling was lower in acidic solutions and higher in neutral and basic solutions and decreased with the increasing ionic strength. Furthermore, SEM results revealed that hydrogel have a rough and fibrous surface structure with numerous pores. Cytotoxicity studies demonstrated that the hydrogel was non-cytotoxic at 50 μg/ml against HeLa cells which suggested a good biocompatibility of the material. TDF was loaded and released from the hydrogels and showed an encapsulation efficiency and drug loading percentage ranging from 81-96% and 8-10%, respectively. TDF release profile was found to be low in buffer solution of pH 1.2 (in the range of 5-10%) and much higher (38-53%) at pH 7.4 within 96 hours. TDF maintained its chemical integrity after release and the hydrogels can therefore be proposed as a new controlled-release drug delivery system for hepatitis B treatment. , Thesis (MSc) -- Faculty of Science, Chemistry, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Safari, Justin Bazibuhe
- Date: 2022-04
- Subjects: Chitosan , Drug delivery systems , Drugs Controlled release , Tenofovir , Colloids , Hepatitis B Chemotherapy , Hydrogel
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/232182 , vital:49969
- Description: Hepatitis B infection is a deadly infectious disease caused by the hepatitis B virus and is responsible for many deaths every year worldwide. Despite medication and vaccines against hepatitis B infection, it still presents high morbidity and mortality among populations. This is partly due to factors such as a long medication period of the existing treatments, resulting in poor patient compliance and leading to treatment failure. In addition, this situation can be responsible for the observed emerging drug resistance. Hence, novel drugs and drug delivery systems are needed to tackle this matter. Many strategies have been used to develop long-acting drug delivery systems treatment for several infectious diseases. Hydrogel drug delivery systems have shown interesting results as controlled drug delivery systems for several drugs. Therefore, the present study aimed to develop chitosan grafted poly (acrylamide-co-acrylic acid) hydrogel and apply it as a pH-sensitive controlled delivery system of tenofovir disoproxil fumarate (TDF). TDF is a nucleoside reverse transcriptase inhibitor used as first-line treatment of hepatitis B chronic infection and in the treatment of other viral infections. The free-radical polymerization method was utilized to modify chitosan by grafting acrylamide and acrylic acid and using N, N’-methylene bisacrylamide as the crosslinking agent to prepare the hydrogel, followed by an optimization of parameters that could affect the swelling capacity. The prepared chitosan-g-poly(acrylamide-co-acrylic acid) hydrogel was characterized using Fourier Transmission Infra-red spectroscopy (FTIR), X-Ray Diffraction (XRD), Thermal Gravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), Energy-dispersive X-ray spectroscopy (EDS), Scanning Electron Microscopy (SEM), and was evaluated for cytotoxicity using a HeLa cell assay. TDF was used as a drug model, it was loaded by the swelling equilibrium method, following by the investigation of the release profile of TDF-loaded hydrogel at pH 1.2 and 7.4. A successful synthesis of chitosan grafted poly(acrylamide-co-acrylic acid) hydrogel was confirmed by Fourier Transmission Infra-red spectroscopy (FTIR), X-Ray Diffraction Spectroscopy (XRD), Thermal Gravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), Energy-dispersive X-ray spectroscopy (EDS) and Scanning Electron Microscopy (SEM). Optimization results showed that the ratio of monomers impacted the swelling ratio of the hydrogel and both the concentration of the crosslinking agent, and the reaction initiator also affected the swelling ratio. The synthesized hydrogels were sensitive to pH and ionic strength. Hydrogel swelling was lower in acidic solutions and higher in neutral and basic solutions and decreased with the increasing ionic strength. Furthermore, SEM results revealed that hydrogel have a rough and fibrous surface structure with numerous pores. Cytotoxicity studies demonstrated that the hydrogel was non-cytotoxic at 50 μg/ml against HeLa cells which suggested a good biocompatibility of the material. TDF was loaded and released from the hydrogels and showed an encapsulation efficiency and drug loading percentage ranging from 81-96% and 8-10%, respectively. TDF release profile was found to be low in buffer solution of pH 1.2 (in the range of 5-10%) and much higher (38-53%) at pH 7.4 within 96 hours. TDF maintained its chemical integrity after release and the hydrogels can therefore be proposed as a new controlled-release drug delivery system for hepatitis B treatment. , Thesis (MSc) -- Faculty of Science, Chemistry, 2022
- Full Text:
- Date Issued: 2022-04
Determining and its effects on perceptual motor skills of soccer players
- Authors: Van Niekerk, Tyra-lee
- Date: 2022-04
- Subjects: Soccer players , Perceptual-motor processes
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/58961 , vital:60251
- Description: Objectives: The influence of detraining on the perceptual motor skills of soccer players has been theorized, but not verified empirically (Farrow & Robertson, 2017). The aim of this study was to examine detraining and its effects on the perceptual-motor skills of soccer players by employing a three-week period of no training, immediately post-season. Method: To further examine the effects that three weeks of no training would have on the perceptual-motor and perceptual-cognitive abilities of soccer players, sixteen male club university soccer players (aged 21.10±2.69 years with 12.40±3.18 years of playing experience) participated in this single-cohort longitudinal observation study. The measurements were performed in the following order with sprint testing encompassing the 40-Meter Sprint Test, aerobic performance testing by use of Intermittent Yo-Yo Test (YYIR2), perceptual-motor testing which consisted of the Loughborough Soccer Passing Test and perceptual-cognitive testing undertaken by means of Video-based assessment. Results: A three-week period of no training showed no negligible effects of detraining on sprint performance (F(2, 30) = 1.43, p = .255, ƞp2 = .09), perceptual-motor performance (F(1, 15) = 2.52, p = .133, ƞp2 = .14) nor effects of detraining regarding perceptual-cognitive aptitudes (F(2, 30)= 0.28, p= .813, ƞp 2= .01 ). Results of the study did, however, suggest the potential for increasing aerobic performance (F(1, 15) = 6.17, p = .025, ƞp2 = .29). Additionally, the study results inferred that within Video-based assessment, university club soccer players may develop a response bias due to familiarity or repeated exposure to the testing procedures. Conclusions: Results from the study fail to comprehensively show the effects of detraining on male club university soccer players in all aspects of the perceptual-skill framework, after three weeks of no training. The researcher further discusses the effects of familiarity, repeated exposure and the robustness of these perceptual-cognitive and perceptual-motor abilities as possible reasons for the results returned. , Thesis (MA) -- Faculty of Health Sciences, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Van Niekerk, Tyra-lee
- Date: 2022-04
- Subjects: Soccer players , Perceptual-motor processes
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/58961 , vital:60251
- Description: Objectives: The influence of detraining on the perceptual motor skills of soccer players has been theorized, but not verified empirically (Farrow & Robertson, 2017). The aim of this study was to examine detraining and its effects on the perceptual-motor skills of soccer players by employing a three-week period of no training, immediately post-season. Method: To further examine the effects that three weeks of no training would have on the perceptual-motor and perceptual-cognitive abilities of soccer players, sixteen male club university soccer players (aged 21.10±2.69 years with 12.40±3.18 years of playing experience) participated in this single-cohort longitudinal observation study. The measurements were performed in the following order with sprint testing encompassing the 40-Meter Sprint Test, aerobic performance testing by use of Intermittent Yo-Yo Test (YYIR2), perceptual-motor testing which consisted of the Loughborough Soccer Passing Test and perceptual-cognitive testing undertaken by means of Video-based assessment. Results: A three-week period of no training showed no negligible effects of detraining on sprint performance (F(2, 30) = 1.43, p = .255, ƞp2 = .09), perceptual-motor performance (F(1, 15) = 2.52, p = .133, ƞp2 = .14) nor effects of detraining regarding perceptual-cognitive aptitudes (F(2, 30)= 0.28, p= .813, ƞp 2= .01 ). Results of the study did, however, suggest the potential for increasing aerobic performance (F(1, 15) = 6.17, p = .025, ƞp2 = .29). Additionally, the study results inferred that within Video-based assessment, university club soccer players may develop a response bias due to familiarity or repeated exposure to the testing procedures. Conclusions: Results from the study fail to comprehensively show the effects of detraining on male club university soccer players in all aspects of the perceptual-skill framework, after three weeks of no training. The researcher further discusses the effects of familiarity, repeated exposure and the robustness of these perceptual-cognitive and perceptual-motor abilities as possible reasons for the results returned. , Thesis (MA) -- Faculty of Health Sciences, 2022
- Full Text:
- Date Issued: 2022-04
Developing a socio- ecological framework for the restoration of estuaries using the Swartkops Estuary as a case study
- Authors: Tsipa, Vusumzi
- Date: 2022-04
- Subjects: Estuarine ecology -- South Africa -- Swartkops River Estuary , Ecosystem
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/59622 , vital:62208
- Description: The aim of this study was to develop and test a socio-ecological systems framework for the restoration of estuaries in South Africa using the Swartkops Estuary as a case study. This necessitated a review of existing SES frameworks that have been developed for use in other disciplines. As part of the newly developed framework, the Swartkops estuary condition was assessed using the Estuary Health Index to understand the present ecological state (PES) of the estuary following from the last assessment done in 2013/2014. The Estuary Health Index is a nationally accepted method of measuring the health of South African estuaries. The state of the societal system was assessed through field observations, engagements with estuary users on-site, insights provided by the Zwartkops Conservancy, and from recent literature. The potential for restoration of habitats for the purpose of carbon storage was also assessed as part of this study. The suitability of disturbed habitats for stimulating future salt marsh growth was investigated since an important incentive for restoration is blue carbon storage. This is important as blue carbon ecosystems offer great potential as a climate change mitigation measure through their ability to sequester carbon. This was done by evaluating plant cover and sediment characteristics at sites along the length of the estuary representing disturbed and undisturbed areas. The estuarine health score for the Swartkops Estuary was found to be 47 out of 100 translating to a PES Category D (largely modified estuary). The main problem in the estuary is water quality along with habitat loss and resource exploitation. The three Wastewater Treatment Works (WWTWs) located upstream of the estuary are the main drivers behind the decline in estuary health in addition to other threats to the water quality which are stormwater run-off inputs from the Motherwell canal and Markman canal. This study showed that the health of the estuary is on a negative trajectory towards a largely degraded estuary. Fishing, bait collection and the use of spiritual sites are the dominant vii ecosystem services used at the estuary. Through the assessment of the state of the societal system, the estuary was highlighted to be a major food source for many people living close to the estuary through subsistence fishing and bait collection for selling to recreational fishers. The estuary is also a health hazard to the very same people that depend on it for survival because of the poor water quality particularly high metal inputs from past and present nearby industrial activities. Restoration plans need to be developed in consideration of the estuary status quo that includes the societal system and the ecosystem services provided by the estuary. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Tsipa, Vusumzi
- Date: 2022-04
- Subjects: Estuarine ecology -- South Africa -- Swartkops River Estuary , Ecosystem
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/59622 , vital:62208
- Description: The aim of this study was to develop and test a socio-ecological systems framework for the restoration of estuaries in South Africa using the Swartkops Estuary as a case study. This necessitated a review of existing SES frameworks that have been developed for use in other disciplines. As part of the newly developed framework, the Swartkops estuary condition was assessed using the Estuary Health Index to understand the present ecological state (PES) of the estuary following from the last assessment done in 2013/2014. The Estuary Health Index is a nationally accepted method of measuring the health of South African estuaries. The state of the societal system was assessed through field observations, engagements with estuary users on-site, insights provided by the Zwartkops Conservancy, and from recent literature. The potential for restoration of habitats for the purpose of carbon storage was also assessed as part of this study. The suitability of disturbed habitats for stimulating future salt marsh growth was investigated since an important incentive for restoration is blue carbon storage. This is important as blue carbon ecosystems offer great potential as a climate change mitigation measure through their ability to sequester carbon. This was done by evaluating plant cover and sediment characteristics at sites along the length of the estuary representing disturbed and undisturbed areas. The estuarine health score for the Swartkops Estuary was found to be 47 out of 100 translating to a PES Category D (largely modified estuary). The main problem in the estuary is water quality along with habitat loss and resource exploitation. The three Wastewater Treatment Works (WWTWs) located upstream of the estuary are the main drivers behind the decline in estuary health in addition to other threats to the water quality which are stormwater run-off inputs from the Motherwell canal and Markman canal. This study showed that the health of the estuary is on a negative trajectory towards a largely degraded estuary. Fishing, bait collection and the use of spiritual sites are the dominant vii ecosystem services used at the estuary. Through the assessment of the state of the societal system, the estuary was highlighted to be a major food source for many people living close to the estuary through subsistence fishing and bait collection for selling to recreational fishers. The estuary is also a health hazard to the very same people that depend on it for survival because of the poor water quality particularly high metal inputs from past and present nearby industrial activities. Restoration plans need to be developed in consideration of the estuary status quo that includes the societal system and the ecosystem services provided by the estuary. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2022
- Full Text:
- Date Issued: 2022-04
Developing an effective HR framework/model to improve HR officials’ performance at the port of Port Elizabeth
- Authors: Maqetuka, Siphokazi Suzanne
- Date: 2022-04
- Subjects: Personnel management , Human Resources Assessment , Human resource professionals
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/57853 , vital:58280
- Description: With rising economic conditions and intense competitive conditions in business development, companies are increasingly facing the need to hire, motivate and retain talented people (Irana Bagaeva, 2018). Therefore, employees with the skills to meet market and customer requirements, regardless of ownership or the range of production in the modern world, are crucial to growth, survival, and sustainability. This emphasises the importance of those who must ensure that the above is achieved, that is, the human resources department of the organisation. The Human Resources Department is considered by business leaders and employees to be the body that builds and evaluates the human resources network that drives the effectiveness of the organization (Vanderpyl, 2018). Organisations need to be able to configure themselves, and HR leaders and teams keep their networks strong by not only satisfying regulations but also by leveraging and addressing social trends that benefit the organisation. Given the background highlighted above, which highlights the importance of an effective Human resource department and the role it ought to play in the organisation’s success, growth, and sustainability, it was therefore sought by the researcher to delve into the effectiveness of the Human resources department at the Port of Port Elizabeth, as they have continually been receiving mediocre performance ratings from the organisation’s leaders. Thus, the purpose of this study was to explore and investigate, from the Human Resource personnel in this department, their opinions of the effectiveness of the service offerings of the Human Resource department of the Port of PE to service the needs of their customers. This led to the development of a qualitative research approach where semi-structured interviews, supported with questionnaires, were conducted on all the personnel of the Human Resource department. The questionnaire contained closed and open-ended statements of opinions held by the respondents, which consisted of the Human resource personnel of the Port of Port Elizabeth. The study findings indicate that the Human Resource Department of the Port of PE is functioning at a mediocre level of service provision and that it is not a high-performing team or highly effective. The impact of mediocre service delivery means that the iii department is not fully meeting the client’s mandate that drives the People agenda of the organisation. There were a few factors identified in the study that prevented the team from reaching levels of high performance, and some can be attributed to organisational, systemic, and policy challenges preventing the team from reaching the required levels of service. A new Operating model has been presented in this study to address these challenges faced by the department. Finally, it was imperative to highlight the context in which the Port of Port Elizabeth exists, that being of Transnet which is a State-Owned enterprise that is therefore owned by the government, which has the mandate to drive the South African Government’s agenda of poverty and unemployment alleviation. , Thesis (MA) -- Faculty of Business and Economic science, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Maqetuka, Siphokazi Suzanne
- Date: 2022-04
- Subjects: Personnel management , Human Resources Assessment , Human resource professionals
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/57853 , vital:58280
- Description: With rising economic conditions and intense competitive conditions in business development, companies are increasingly facing the need to hire, motivate and retain talented people (Irana Bagaeva, 2018). Therefore, employees with the skills to meet market and customer requirements, regardless of ownership or the range of production in the modern world, are crucial to growth, survival, and sustainability. This emphasises the importance of those who must ensure that the above is achieved, that is, the human resources department of the organisation. The Human Resources Department is considered by business leaders and employees to be the body that builds and evaluates the human resources network that drives the effectiveness of the organization (Vanderpyl, 2018). Organisations need to be able to configure themselves, and HR leaders and teams keep their networks strong by not only satisfying regulations but also by leveraging and addressing social trends that benefit the organisation. Given the background highlighted above, which highlights the importance of an effective Human resource department and the role it ought to play in the organisation’s success, growth, and sustainability, it was therefore sought by the researcher to delve into the effectiveness of the Human resources department at the Port of Port Elizabeth, as they have continually been receiving mediocre performance ratings from the organisation’s leaders. Thus, the purpose of this study was to explore and investigate, from the Human Resource personnel in this department, their opinions of the effectiveness of the service offerings of the Human Resource department of the Port of PE to service the needs of their customers. This led to the development of a qualitative research approach where semi-structured interviews, supported with questionnaires, were conducted on all the personnel of the Human Resource department. The questionnaire contained closed and open-ended statements of opinions held by the respondents, which consisted of the Human resource personnel of the Port of Port Elizabeth. The study findings indicate that the Human Resource Department of the Port of PE is functioning at a mediocre level of service provision and that it is not a high-performing team or highly effective. The impact of mediocre service delivery means that the iii department is not fully meeting the client’s mandate that drives the People agenda of the organisation. There were a few factors identified in the study that prevented the team from reaching levels of high performance, and some can be attributed to organisational, systemic, and policy challenges preventing the team from reaching the required levels of service. A new Operating model has been presented in this study to address these challenges faced by the department. Finally, it was imperative to highlight the context in which the Port of Port Elizabeth exists, that being of Transnet which is a State-Owned enterprise that is therefore owned by the government, which has the mandate to drive the South African Government’s agenda of poverty and unemployment alleviation. , Thesis (MA) -- Faculty of Business and Economic science, 2022
- Full Text:
- Date Issued: 2022-04
Development and training projects for poverty alleviation in Zwide township Qgeberha
- Authors: Ngqezana, Amanda
- Date: 2022-04
- Subjects: Economic aspects -- South Africa , Economic development projects -- South Africa -- Port Elizabeth
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/58069 , vital:58535
- Description: The purpose of this study was to establish what projects have been implemented in Zwide Township in Gqeberha to alleviate poverty. Criteria for a successful poverty alleviation project were identified guided by the factors that determine poverty and the sustainability of the development and training projects in place to alleviate poverty. This study assessed existing projects to ascertain where they were successful and where they could improve. The study revealed that several projects and programmes have been planned in Gqeberha, specifically for Zwide Township, to alleviate poverty but according to Nelson Mandela Bay’s IDP (2017:04), several projects have been placed on hold due to a lack of funds. This was a qualitative study that employed documentary analysis to gather relevant data. The study concluded that the Nelson Mandela Bay Expanded Public Works Programme is currently in operation in Zwide Township and should continue to target unemployed youth and adults to alleviate poverty. , Thesis (MA) -- Faculty of Business and Economic science, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Ngqezana, Amanda
- Date: 2022-04
- Subjects: Economic aspects -- South Africa , Economic development projects -- South Africa -- Port Elizabeth
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/58069 , vital:58535
- Description: The purpose of this study was to establish what projects have been implemented in Zwide Township in Gqeberha to alleviate poverty. Criteria for a successful poverty alleviation project were identified guided by the factors that determine poverty and the sustainability of the development and training projects in place to alleviate poverty. This study assessed existing projects to ascertain where they were successful and where they could improve. The study revealed that several projects and programmes have been planned in Gqeberha, specifically for Zwide Township, to alleviate poverty but according to Nelson Mandela Bay’s IDP (2017:04), several projects have been placed on hold due to a lack of funds. This was a qualitative study that employed documentary analysis to gather relevant data. The study concluded that the Nelson Mandela Bay Expanded Public Works Programme is currently in operation in Zwide Township and should continue to target unemployed youth and adults to alleviate poverty. , Thesis (MA) -- Faculty of Business and Economic science, 2022
- Full Text:
- Date Issued: 2022-04
Development of a distributed optical fiber sensor for geological applications
- Authors: James, Jena
- Date: 2022-04
- Subjects: Polymers--Optical properties -- South Africa , Detectors—Materials
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/56156 , vital:55973
- Description: The purpose of the study was to develop a distributed optical fiber acoustic sensor for monitoring ground subsidence before collapse sinkholes form causing costly damage on infrastructure. Costs in excess of R1.3 billion have been incurred while dealing with sinkhole related measures in South Africa. Monitoring sinkholes and the presence of an early warning alert system can drastically reduce the impact, risk and cost caused by sudden ground collapse. A related goal was to construct a reliable collapse alert early warning system to facilitate disaster preparedness and avoid further damage from accidents. This was achieved by developing a spectroscopic shift monitoring algorithm which analysed changes in the subsurface vibration modes using ambient noise signals. For the first time to our knowledge, an optic fiber sensor with an early warning alarm, using ambient noise vibrations to detect and monitor sinkholes was developed at NMU. A polarisation-based, interferometric optical fiber seismic sensor was developed and compared to a commercial geophone. The fiber sensor exhibited superior performance in sensitivity, bandwidth, signal response and recovery times. The sensitivity of the optical fiber sensor was 0.47 rad/Pa surpassing the geophone sensitivity by 9.32%, and the bandwidth of 3.349kHz was 20 times greater for the optical fiber sensor. The fiber sensor was used to measure millisecond events as the impact duration of a bouncing ball was successfully obtained. It was used to detect sinkhole formation in the simulator model, designed. Ground collapse precursors were identified, and early warning alert was achieved using the spectral analysis algorithm, developed. The collapse precursor condition was identified as a functional combination of variations in the peak frequency, bandwidth and peak intensity. A distributed acoustic sensor was built to detect ambient noise induced subsurface signals. Vibrations were located along the 28km length of optical fiber with a relative error of 9.6%. The sensor demonstrated a frequency response range of 212.25Hz, an event distance precision of 224m with time resolution of 1.12µs, and a spatial resolution of 1km. The position of disturbance was measured within 300m of its actual point of 3.21km along the optical fiber. The results showed that distributed optical fiber sensing allows real-time monitoring of the subsurface over extended distances, using ambient noise signals. , Thesis (PhD) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: James, Jena
- Date: 2022-04
- Subjects: Polymers--Optical properties -- South Africa , Detectors—Materials
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/56156 , vital:55973
- Description: The purpose of the study was to develop a distributed optical fiber acoustic sensor for monitoring ground subsidence before collapse sinkholes form causing costly damage on infrastructure. Costs in excess of R1.3 billion have been incurred while dealing with sinkhole related measures in South Africa. Monitoring sinkholes and the presence of an early warning alert system can drastically reduce the impact, risk and cost caused by sudden ground collapse. A related goal was to construct a reliable collapse alert early warning system to facilitate disaster preparedness and avoid further damage from accidents. This was achieved by developing a spectroscopic shift monitoring algorithm which analysed changes in the subsurface vibration modes using ambient noise signals. For the first time to our knowledge, an optic fiber sensor with an early warning alarm, using ambient noise vibrations to detect and monitor sinkholes was developed at NMU. A polarisation-based, interferometric optical fiber seismic sensor was developed and compared to a commercial geophone. The fiber sensor exhibited superior performance in sensitivity, bandwidth, signal response and recovery times. The sensitivity of the optical fiber sensor was 0.47 rad/Pa surpassing the geophone sensitivity by 9.32%, and the bandwidth of 3.349kHz was 20 times greater for the optical fiber sensor. The fiber sensor was used to measure millisecond events as the impact duration of a bouncing ball was successfully obtained. It was used to detect sinkhole formation in the simulator model, designed. Ground collapse precursors were identified, and early warning alert was achieved using the spectral analysis algorithm, developed. The collapse precursor condition was identified as a functional combination of variations in the peak frequency, bandwidth and peak intensity. A distributed acoustic sensor was built to detect ambient noise induced subsurface signals. Vibrations were located along the 28km length of optical fiber with a relative error of 9.6%. The sensor demonstrated a frequency response range of 212.25Hz, an event distance precision of 224m with time resolution of 1.12µs, and a spatial resolution of 1km. The position of disturbance was measured within 300m of its actual point of 3.21km along the optical fiber. The results showed that distributed optical fiber sensing allows real-time monitoring of the subsurface over extended distances, using ambient noise signals. , Thesis (PhD) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2022
- Full Text:
- Date Issued: 2022-04
Early maladaptive schemas among re-offenders in Gqeberha 102
- Authors: Mantshiyose, Asisipho
- Date: 2022-04
- Subjects: Recidivism -- Gqeberha
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/58904 , vital:60246
- Description: high crime rate in South Africa showed an increase in 2018 with recidivism being the highest contributing factor. The increase in recidivism rates is a result of many factors, including the ineffectiveness of rehabilitation programmes. In an attempt to combat the increase in recidivism, its causes have been examined from a number of perspectives, especially social factors. However, very few studies have focussed on psychological factors when studying crime in South Africa. International studies have found personality factors to be a contributing factor towards recidivism. Concordantly, international studies have also established a correlation between early maladaptive schemas, a core component of personality, and crime. This study aimed to explore early maladaptive schemas among reoffenders in Gqeberha, South Africa. The objective of the study was to establish the prevalence of EMS in a sample of repeat offenders from the National Institute for Crime Prevention and the Reintegration of Offenders (NICRO) in Gqeberha. The study used a quantitative methodology and a sample size of 14 participants was utilised. Convenience sampling was utilised to identify reoffenders. The data was collected by administering a short demographical questionnaire and the Young Schema Questionnaire (YSQ). Descriptive statistics and Spearman’s correlations were utilised to analyse the data. , Thesis (MA) -- Faculty of Health Sciences, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Mantshiyose, Asisipho
- Date: 2022-04
- Subjects: Recidivism -- Gqeberha
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/58904 , vital:60246
- Description: high crime rate in South Africa showed an increase in 2018 with recidivism being the highest contributing factor. The increase in recidivism rates is a result of many factors, including the ineffectiveness of rehabilitation programmes. In an attempt to combat the increase in recidivism, its causes have been examined from a number of perspectives, especially social factors. However, very few studies have focussed on psychological factors when studying crime in South Africa. International studies have found personality factors to be a contributing factor towards recidivism. Concordantly, international studies have also established a correlation between early maladaptive schemas, a core component of personality, and crime. This study aimed to explore early maladaptive schemas among reoffenders in Gqeberha, South Africa. The objective of the study was to establish the prevalence of EMS in a sample of repeat offenders from the National Institute for Crime Prevention and the Reintegration of Offenders (NICRO) in Gqeberha. The study used a quantitative methodology and a sample size of 14 participants was utilised. Convenience sampling was utilised to identify reoffenders. The data was collected by administering a short demographical questionnaire and the Young Schema Questionnaire (YSQ). Descriptive statistics and Spearman’s correlations were utilised to analyse the data. , Thesis (MA) -- Faculty of Health Sciences, 2022
- Full Text:
- Date Issued: 2022-04
Effect of fire severity on Afrotemperate forest tree survival
- Authors: Giddey, Brandon Louis
- Date: 2022-04
- Subjects: Trees -- Mortality , Wildfires
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/57413 , vital:57635
- Description: Weather patterns have changed globally with increased fire danger weather conditions, along with poor management and fire suppression, likely contributing to the increase in prevalence of large wildfires. Ecosystems such as temperate broad-leaved forests, where fire is limited by climatic conditions, are particularly at risk of altered fire regimes related to climate change. It is thus important to monitor the effects of fire in these ecosystems. Satellite remote sensing is a cost-effective way to assess spatial variability of fire effects on a landscape scale and has become an increasingly used tool for studying fire severity. In the southern Cape of South Africa during October-November 2018, a large wildfire burnt patches of Southern Cape Afrotemperate Forest (hereafter ‘Afrotemperate forest’). This provided an opportunity to investigate the accuracy of a satellite index for fire severity and the effect of fire on Afrotemperate forest survival. The first objective was to verify through field observations the accuracy of the differenced Normalised Burn Ratio (dNBR) as an index of fire severity derived from Sentinel 2 images in Afrotemperate forest. The second objective was to investigate the effect of fire severity and tree size on the post-fire survival of Afrotemperate forest tree species. For the first objective, stem fire severity, estimated from observed damage to the main stem, was recorded for 1 648 trees in 87 plots and linear regression used to test whether the observed measure of fire severity was related to dNBR. For the second objective, stem fire severity and tree survival 19-24 months post-fire were recorded for 40 species and 1 378 trees in 88 plots. Trees were considered to have survived if they resprouted from the main stem or had green foliage in the canopy. The survival response was assessed in relation to stem fire severity and tree size for all trees collectively and for 10 species (with sample size > 40) individually, using logistic regression. A strong linear relationship between dNBR and stem fire severity (r2 = 0.69, p < 0.001) confirmed the accuracy of dNBR as a measure of fire severity in Afrotemperate forest. In the fire investigated, 4 628 ha of Afrotemperate forest burnt of which 67% burnt at low severity, 21% at medium severity and 12% at high severity. The dNBR values associated with fire severity categories were comparable between Afrotemperate and North American forests, suggesting that dNBR values are relatively standard across forest types. Information on the distribution of fire severity vi facilitates investigation of further questions regarding past and future fire regimes and the fire ecology of Afrotemperate forest. The post-fire survival rate of Afrotemperate forest trees was 45% which is comparable to that in coniferous forests of North America but lower than that in temperate forests of Australia and Portugal and the neighbouring dune thicket which shares several species with Afrotemperate forest. Fire severity had a significant negative effect on survival and tree size a significant positive effect. Total variance explained by the model (for species collectively) was 40.8%, of which fire severity and tree size combined explained 13.2%, and species as random factor, 27.6%. Respective tree species showed differential survival responses – four species showed high survival (> 60% of individuals), while five species showed low survival (< 40%). This study was the first post-fire assessment of the resprouting ability of Afrotemperate forest trees and a third of the trees surveyed (for species collectively) resprouted from the stem. This suggested that resprouting from the stem is a primary means of post-fire recovery in Afrotemperate forest trees, in contrast with previous assertions that several common canopy species, including Podocarpus latifolius, Afrocarpus falcatus, Scutia myrtina, Scolopia mundii and Rapanea melanophloeos, are unable to resprout. Varying resilience to fire among species supports previous suggestions that fire affects species’ composition and diversity in these forests and calls for careful management of fire regimes in the face of global change. , Thesis (MSc) -- Faculty of Science, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Giddey, Brandon Louis
- Date: 2022-04
- Subjects: Trees -- Mortality , Wildfires
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/57413 , vital:57635
- Description: Weather patterns have changed globally with increased fire danger weather conditions, along with poor management and fire suppression, likely contributing to the increase in prevalence of large wildfires. Ecosystems such as temperate broad-leaved forests, where fire is limited by climatic conditions, are particularly at risk of altered fire regimes related to climate change. It is thus important to monitor the effects of fire in these ecosystems. Satellite remote sensing is a cost-effective way to assess spatial variability of fire effects on a landscape scale and has become an increasingly used tool for studying fire severity. In the southern Cape of South Africa during October-November 2018, a large wildfire burnt patches of Southern Cape Afrotemperate Forest (hereafter ‘Afrotemperate forest’). This provided an opportunity to investigate the accuracy of a satellite index for fire severity and the effect of fire on Afrotemperate forest survival. The first objective was to verify through field observations the accuracy of the differenced Normalised Burn Ratio (dNBR) as an index of fire severity derived from Sentinel 2 images in Afrotemperate forest. The second objective was to investigate the effect of fire severity and tree size on the post-fire survival of Afrotemperate forest tree species. For the first objective, stem fire severity, estimated from observed damage to the main stem, was recorded for 1 648 trees in 87 plots and linear regression used to test whether the observed measure of fire severity was related to dNBR. For the second objective, stem fire severity and tree survival 19-24 months post-fire were recorded for 40 species and 1 378 trees in 88 plots. Trees were considered to have survived if they resprouted from the main stem or had green foliage in the canopy. The survival response was assessed in relation to stem fire severity and tree size for all trees collectively and for 10 species (with sample size > 40) individually, using logistic regression. A strong linear relationship between dNBR and stem fire severity (r2 = 0.69, p < 0.001) confirmed the accuracy of dNBR as a measure of fire severity in Afrotemperate forest. In the fire investigated, 4 628 ha of Afrotemperate forest burnt of which 67% burnt at low severity, 21% at medium severity and 12% at high severity. The dNBR values associated with fire severity categories were comparable between Afrotemperate and North American forests, suggesting that dNBR values are relatively standard across forest types. Information on the distribution of fire severity vi facilitates investigation of further questions regarding past and future fire regimes and the fire ecology of Afrotemperate forest. The post-fire survival rate of Afrotemperate forest trees was 45% which is comparable to that in coniferous forests of North America but lower than that in temperate forests of Australia and Portugal and the neighbouring dune thicket which shares several species with Afrotemperate forest. Fire severity had a significant negative effect on survival and tree size a significant positive effect. Total variance explained by the model (for species collectively) was 40.8%, of which fire severity and tree size combined explained 13.2%, and species as random factor, 27.6%. Respective tree species showed differential survival responses – four species showed high survival (> 60% of individuals), while five species showed low survival (< 40%). This study was the first post-fire assessment of the resprouting ability of Afrotemperate forest trees and a third of the trees surveyed (for species collectively) resprouted from the stem. This suggested that resprouting from the stem is a primary means of post-fire recovery in Afrotemperate forest trees, in contrast with previous assertions that several common canopy species, including Podocarpus latifolius, Afrocarpus falcatus, Scutia myrtina, Scolopia mundii and Rapanea melanophloeos, are unable to resprout. Varying resilience to fire among species supports previous suggestions that fire affects species’ composition and diversity in these forests and calls for careful management of fire regimes in the face of global change. , Thesis (MSc) -- Faculty of Science, 2022
- Full Text:
- Date Issued: 2022-04
Effect of pomegranate (Punica granatum L) peel powder meal on growth performance, gut integrity, haemato-biochemical indices, meat, and bone quality of broiler chickens
- Akuru, Eunice Amaka https://orcid.org/0000-0002-3093-0247
- Authors: Akuru, Eunice Amaka https://orcid.org/0000-0002-3093-0247
- Date: 2022-04
- Subjects: Broilers (Chickens) , Meat -- Quality
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/23611 , vital:58218
- Description: The objective of the current study was to investigate the overall response of broiler birds to varying dietary levels of pomegranate (Punica granatum L) peel powder meal (PPPM). A total of 432-day-old Cobb 500 broiler chicks were randomly divided into six experimental groups of four replications with 18 birds per replicate in a completely randomized design (CRD). The birds were fed isonitrogenous and isocaloric experimental diets designated as: T1-control diet with 0percent additives (negative control; NEGCON); T2- control diet supplemented with α-tocopherol acetate at 200g per ton (positive control; POSCON): T3, T4, T5 and T6-control diet supplemented with 2, 4, 6 and 8g/kg PPPM (PPPM2, PPPM4, PPPM6, PPPM8). The phytochemical, nutritional and antioxidant properties of the pomegranate peel powder were determined. Results showed that the South African-grown pomegranate peel (“Wonderful” variety) had rich protein and trace mineral contents. Higher (p < 0.05) antioxidant and hepatic anti-lipid peroxidative activities were recorded in the ethanol and acetone extracts than the water extract, whereas the three extracts had no toxic effects on liver and kidney cells (p > 0.05). The dietary effects of PPPM supplementation on growth performance, digestibility, carcass, and organ weight indices of Cobb 500 birds were determined. The POSCON diet enhanced (p < 0.05) feed conversion ratio (FCR) at week 3. The average final body weight and average daily weight gain were highest (p < 0.05) in birds fed PPPM2 and PPPM4 diets, whereas birds fed PPPM2 diet had enhanced (p < 0.05) FCR and protein efficiency ratio when compared with birds on POSCON. Thigh and breast weights were highest (p < 0.05) in birds on PPPM4 and PPPM8 diets, whereas birds fed PPPM4 diet had enhanced (p < 0.05) nutrient digestibility compared with those on POSCON. The antioxidant status and breast meat quality of Cobb 500 broiler birds fed diets supplemented with PPPM were determined. Meat from birds fed PPPM8 diet had the highest (p < 0.05) thawing loss, while cooking loss was lowest (p < 0.05) in the PPPM2 group. The highest (p < 0.05) ability to scavenge ABTS [(2, 2-azinobis (3ethylbenzothiazoline-6 sulfonic acid))] radical cation (ABTS+) was recorded in the PPPM2 and PPPM4 meat while PPPM8 meat had increased (p < 0.05) catalase activity. The fatty acid composition, oxidative status, and drip loss in breast meat of Cobb 500 broiler birds fed graded levels of PPPM was determined. Meat from birds fed PPPM4 diet had the lowest (p < 0.05) margaric (C17:0) and arachidic (C20:0) acids, while meat from birds fed PPPM8 diet had higher (p < 0.05) levels of eicosadenoic (C20:2, n-6) and arachidonic (AA, 20:4) acids. The POSCON had higher (p < 0.05) ability to reduce TBARS levels in meat on day-1 and day-16 of storage than the NEGCON and PPPM diets, whereas TBARS levels were lowest (p < 0.05) in PPPM6 meat on day-16. The gut pH, histology, haematology, serum-biochemical indices, and bone quality parameters of Cobb 500 broiler birds fed diets supplemented with PPPM was determined. Birds fed POSCON, PPM2 and PPPM4 diets had the lowest (p < 0.05) pH in the duodenum, jejunum, and caecum, whereas duodenal pH values were lowest (p < 0.05) in birds fed PPPM2 and PPPM4 diets compared with birds on NEGCON. Birds fed PPPM4 diet had the highest (p < 0.01) duodenal, jejunal and ileal villi height (VH), and the highest (p < 0.01) VH to crypt depth (CD) ratio in the duodenum, jejunum, and ileum. The lowest (p < 0.05) CD in the duodenum, jejunum and ileum was also recorded in birds fed PPPM4 diet. Birds fed PPPM8 diet had higher (p < 0.05) values for white blood cell count, red blood cell count, haemoglobin concentration and packed cell volume, whereas the lowest (p < 0.05) concentration of serum aspartate transaminase was recorded in birds fed PPPM4 diet. Birds on PPM4 diet had longer (p < 0.05) bones. Bone weight and bone breaking strength were highest (p < 0.05) in birds fed PPPM8 diet. Tibia zinc and iron concentrations increased as the inclusion levels of pomegranate peel powder meal increased. It was concluded that broiler birds require 4 g/kg pomegranate peel powder for enhanced growth performance, nutrient digestibility, gut histology, quality, and antioxidant enzyme activity of meat, whereas 8 g/kg pomegranate peel powder meal supplementation is required for enhanced heamato-biochemical indices, bone quality, fatty acid composition and lipid peroxidative parameters in broiler birds. , Thesis (PhD) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Akuru, Eunice Amaka https://orcid.org/0000-0002-3093-0247
- Date: 2022-04
- Subjects: Broilers (Chickens) , Meat -- Quality
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/23611 , vital:58218
- Description: The objective of the current study was to investigate the overall response of broiler birds to varying dietary levels of pomegranate (Punica granatum L) peel powder meal (PPPM). A total of 432-day-old Cobb 500 broiler chicks were randomly divided into six experimental groups of four replications with 18 birds per replicate in a completely randomized design (CRD). The birds were fed isonitrogenous and isocaloric experimental diets designated as: T1-control diet with 0percent additives (negative control; NEGCON); T2- control diet supplemented with α-tocopherol acetate at 200g per ton (positive control; POSCON): T3, T4, T5 and T6-control diet supplemented with 2, 4, 6 and 8g/kg PPPM (PPPM2, PPPM4, PPPM6, PPPM8). The phytochemical, nutritional and antioxidant properties of the pomegranate peel powder were determined. Results showed that the South African-grown pomegranate peel (“Wonderful” variety) had rich protein and trace mineral contents. Higher (p < 0.05) antioxidant and hepatic anti-lipid peroxidative activities were recorded in the ethanol and acetone extracts than the water extract, whereas the three extracts had no toxic effects on liver and kidney cells (p > 0.05). The dietary effects of PPPM supplementation on growth performance, digestibility, carcass, and organ weight indices of Cobb 500 birds were determined. The POSCON diet enhanced (p < 0.05) feed conversion ratio (FCR) at week 3. The average final body weight and average daily weight gain were highest (p < 0.05) in birds fed PPPM2 and PPPM4 diets, whereas birds fed PPPM2 diet had enhanced (p < 0.05) FCR and protein efficiency ratio when compared with birds on POSCON. Thigh and breast weights were highest (p < 0.05) in birds on PPPM4 and PPPM8 diets, whereas birds fed PPPM4 diet had enhanced (p < 0.05) nutrient digestibility compared with those on POSCON. The antioxidant status and breast meat quality of Cobb 500 broiler birds fed diets supplemented with PPPM were determined. Meat from birds fed PPPM8 diet had the highest (p < 0.05) thawing loss, while cooking loss was lowest (p < 0.05) in the PPPM2 group. The highest (p < 0.05) ability to scavenge ABTS [(2, 2-azinobis (3ethylbenzothiazoline-6 sulfonic acid))] radical cation (ABTS+) was recorded in the PPPM2 and PPPM4 meat while PPPM8 meat had increased (p < 0.05) catalase activity. The fatty acid composition, oxidative status, and drip loss in breast meat of Cobb 500 broiler birds fed graded levels of PPPM was determined. Meat from birds fed PPPM4 diet had the lowest (p < 0.05) margaric (C17:0) and arachidic (C20:0) acids, while meat from birds fed PPPM8 diet had higher (p < 0.05) levels of eicosadenoic (C20:2, n-6) and arachidonic (AA, 20:4) acids. The POSCON had higher (p < 0.05) ability to reduce TBARS levels in meat on day-1 and day-16 of storage than the NEGCON and PPPM diets, whereas TBARS levels were lowest (p < 0.05) in PPPM6 meat on day-16. The gut pH, histology, haematology, serum-biochemical indices, and bone quality parameters of Cobb 500 broiler birds fed diets supplemented with PPPM was determined. Birds fed POSCON, PPM2 and PPPM4 diets had the lowest (p < 0.05) pH in the duodenum, jejunum, and caecum, whereas duodenal pH values were lowest (p < 0.05) in birds fed PPPM2 and PPPM4 diets compared with birds on NEGCON. Birds fed PPPM4 diet had the highest (p < 0.01) duodenal, jejunal and ileal villi height (VH), and the highest (p < 0.01) VH to crypt depth (CD) ratio in the duodenum, jejunum, and ileum. The lowest (p < 0.05) CD in the duodenum, jejunum and ileum was also recorded in birds fed PPPM4 diet. Birds fed PPPM8 diet had higher (p < 0.05) values for white blood cell count, red blood cell count, haemoglobin concentration and packed cell volume, whereas the lowest (p < 0.05) concentration of serum aspartate transaminase was recorded in birds fed PPPM4 diet. Birds on PPM4 diet had longer (p < 0.05) bones. Bone weight and bone breaking strength were highest (p < 0.05) in birds fed PPPM8 diet. Tibia zinc and iron concentrations increased as the inclusion levels of pomegranate peel powder meal increased. It was concluded that broiler birds require 4 g/kg pomegranate peel powder for enhanced growth performance, nutrient digestibility, gut histology, quality, and antioxidant enzyme activity of meat, whereas 8 g/kg pomegranate peel powder meal supplementation is required for enhanced heamato-biochemical indices, bone quality, fatty acid composition and lipid peroxidative parameters in broiler birds. , Thesis (PhD) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-04
Encapsulation of flame retardants for lithium-ion battery safety
- Authors: Ntombela, Nompilo Princess
- Date: 2022-04
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/55412 , vital:51993
- Description: Lithium-ion technology takes the lead in electric mobility systems, resulting in an increase in the global demand for Li-ion batteries; however, these batteries are associated with numerous safety concerns. Additionally, there are high costs, high energy and power issues which are some of its key limitations. Research efforts are focused on overcoming these obstacles, with different approaches being explored, such as the investigation of more stable salts, modification of active materials and organic solvents, and the use of electrolyte additives. This study focused specifically on electrolyte additives since the electrolyte is one of the most unstable components of the battery. The electrolyte’s decomposition is one of the reactions that occur inside a battery, which may occur due to overcharging or due to an internal short circuit, amongst others. The electrolyte’s decomposition occurs at the early stages of the thermal runaway process and forms part of the reactions that lead to fires and explosions. Thus, this research aims to develop suitable electrolyte additives to improve the safety aspects of Li-ion batteries. Flame retardant additives show great promise in reducing the flammability of the electrolyte in Li-ion batteries, since they serve to suppress the chemical reactions associated with battery ignition. They retard the fires by scavenging the active radical species formed during the decomposition reaction. In this study, the use of flame retardants was investigated. Flame retardant additives have shown to have flame impeding properties inside a battery; however, their direct addition to the electrolyte tends to cause adverse effects on the ionic conductivity and electrochemical performance of the cells. This study investigated an alternative option - the option to microencapsulate such additives into a neutral compound to ensure that the flame retardant has minimal/no effect on the performance of the battery. This investigation looked at tris(2-butoxyethyl) phosphate (TBP) and bis(2,2,2-trifluoroethyl) methylphosphonate (BFP) as flame retardant additives for the electrolyte. The TBP and BFP flame retardants were microencapsulated in poly(urea formaldehyde) (PUF) coating material via in situ polymerization method. The capsules were characterized using various analytical techniques - to prove it was successfully encapsulated. Electrochemical studies were further done on the capsules and neat flame retardants inside a coin cell. Self-extinguishing time (SET), which is the flammability test, proved that the additives have flame retarding abilities. Opto-digital microscopy (DSX) and scanning electron microscopy (SEM) did confirm the spherical shape of the microcapsules, where SEM also showed the smooth outer layer of the microcapsules and its hollow inner side. Fourier transform infrared spectroscopy (FTIR) proved the presence of the TBP and BFP inside the PUF resin by showing that the chemical composition of microcapsules consisted of both the PUF and flame retardant additives. Simultaneous DSC-TGA (DST) was also performed which showed that the microcapsules were stable before 200 °C, which indicates it would not decompose before the thermal runaway events are occurring. TGA analysis did show that the microcapsules underwent multiple decomposition steps upon heating. Additionally, 31P nuclear magnetic resonance (NMR) was used to quantify the amount of flame retardants additives encapsulated inside PUF shell, and also confirmed the stability of the microcapsules for one month in the electrolyte and at temperatures up to 200 °C. The ionic conductivity was vastly decreased when the flame retardants were added directly to the electrolyte. However, adding the flame retardants in a form of capsules had minimal effect on the ionic conductivity. The cycle capacities of the capsules were also improved when the capsules were added to the cell compared to that of neat flame retardants. The same effect was also noticed when doing Electrochemical Impedance Spectroscopy (EIS). This shows that microencapsulation improves the resistance of the cell caused by the flame retardant in comparison to when added directly to the electrolyte of the cell. , Thesis (MSC) -- Faculty of Science, School of Biomolecular and Chemical Sciences, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Ntombela, Nompilo Princess
- Date: 2022-04
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/55412 , vital:51993
- Description: Lithium-ion technology takes the lead in electric mobility systems, resulting in an increase in the global demand for Li-ion batteries; however, these batteries are associated with numerous safety concerns. Additionally, there are high costs, high energy and power issues which are some of its key limitations. Research efforts are focused on overcoming these obstacles, with different approaches being explored, such as the investigation of more stable salts, modification of active materials and organic solvents, and the use of electrolyte additives. This study focused specifically on electrolyte additives since the electrolyte is one of the most unstable components of the battery. The electrolyte’s decomposition is one of the reactions that occur inside a battery, which may occur due to overcharging or due to an internal short circuit, amongst others. The electrolyte’s decomposition occurs at the early stages of the thermal runaway process and forms part of the reactions that lead to fires and explosions. Thus, this research aims to develop suitable electrolyte additives to improve the safety aspects of Li-ion batteries. Flame retardant additives show great promise in reducing the flammability of the electrolyte in Li-ion batteries, since they serve to suppress the chemical reactions associated with battery ignition. They retard the fires by scavenging the active radical species formed during the decomposition reaction. In this study, the use of flame retardants was investigated. Flame retardant additives have shown to have flame impeding properties inside a battery; however, their direct addition to the electrolyte tends to cause adverse effects on the ionic conductivity and electrochemical performance of the cells. This study investigated an alternative option - the option to microencapsulate such additives into a neutral compound to ensure that the flame retardant has minimal/no effect on the performance of the battery. This investigation looked at tris(2-butoxyethyl) phosphate (TBP) and bis(2,2,2-trifluoroethyl) methylphosphonate (BFP) as flame retardant additives for the electrolyte. The TBP and BFP flame retardants were microencapsulated in poly(urea formaldehyde) (PUF) coating material via in situ polymerization method. The capsules were characterized using various analytical techniques - to prove it was successfully encapsulated. Electrochemical studies were further done on the capsules and neat flame retardants inside a coin cell. Self-extinguishing time (SET), which is the flammability test, proved that the additives have flame retarding abilities. Opto-digital microscopy (DSX) and scanning electron microscopy (SEM) did confirm the spherical shape of the microcapsules, where SEM also showed the smooth outer layer of the microcapsules and its hollow inner side. Fourier transform infrared spectroscopy (FTIR) proved the presence of the TBP and BFP inside the PUF resin by showing that the chemical composition of microcapsules consisted of both the PUF and flame retardant additives. Simultaneous DSC-TGA (DST) was also performed which showed that the microcapsules were stable before 200 °C, which indicates it would not decompose before the thermal runaway events are occurring. TGA analysis did show that the microcapsules underwent multiple decomposition steps upon heating. Additionally, 31P nuclear magnetic resonance (NMR) was used to quantify the amount of flame retardants additives encapsulated inside PUF shell, and also confirmed the stability of the microcapsules for one month in the electrolyte and at temperatures up to 200 °C. The ionic conductivity was vastly decreased when the flame retardants were added directly to the electrolyte. However, adding the flame retardants in a form of capsules had minimal effect on the ionic conductivity. The cycle capacities of the capsules were also improved when the capsules were added to the cell compared to that of neat flame retardants. The same effect was also noticed when doing Electrochemical Impedance Spectroscopy (EIS). This shows that microencapsulation improves the resistance of the cell caused by the flame retardant in comparison to when added directly to the electrolyte of the cell. , Thesis (MSC) -- Faculty of Science, School of Biomolecular and Chemical Sciences, 2022
- Full Text:
- Date Issued: 2022-04
Enterprise development funds as a catalyst for growth and sustainability of black-owned SMMEs in manufacturing
- Authors: Tsheketshe, Yomelela Mfundo
- Date: 2022-04
- Subjects: Business enterprises, Black -- South Africa , Small business
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/58223 , vital:58742
- Description: South Africa is confronted with a skewed economy along racial lines through a history of colonialism and apartheid. The laws of government have tried to include companies in advancing social cohesion and in dealing with issues of the historical exclusion of African communities from the mainstream economy. With the advent of democracy, the government has been faced with the mammoth task of driving transformation and inclusion in various sectors of the economy. Various pieces of legislation have been promulgated to give effect to this ideal. The Broad Based Black Economic Empowerment (BBBEE) Act with its associated regulations has Enterprise and Supplier development (ESD) as one of the five pillars underpinning the targeted areas for transformation in companies. Enterprise development is a key contributor to companies achieving a good score card rating as determined by the government of South Africa for various industries. This scoring also has advantages in terms of accessing government incentives as well as procurement opportunities for businesses with government. Companies therefore deploy capital for the development of businesses within their supply chains and also any other businesses whether or not they do business with them. This process of enterprise development funding is largely undefined and sees companies use various methods and criteria to deploy the capital with a myriad of outcomes all of which vary depending on the area of interest. The primary intent of the enterprise development funds is to create patient, free and sometimes affordable capital for the growth and sustainability of previously disadvantaged businesses in the South African context. Industries like manufacturing, in their nature are capital intensive and require huge capital outlays which then become a barrier to entry particularly for previously disadvantaged groupings like black people. The aim of the study is to identify key determinants that can unlock the growth and sustainability of black owned SMMEs in the manufacturing sector and also to understand the environment in which they operate. It is intended to assist policy makers, enterprise development practitioners, regulators and the beneficiaries of enterprise development on what can be done to ensure that this critical programme achieves its desired outcome. , Thesis (MA) -- Faculty of Business and Economic science, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Tsheketshe, Yomelela Mfundo
- Date: 2022-04
- Subjects: Business enterprises, Black -- South Africa , Small business
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/58223 , vital:58742
- Description: South Africa is confronted with a skewed economy along racial lines through a history of colonialism and apartheid. The laws of government have tried to include companies in advancing social cohesion and in dealing with issues of the historical exclusion of African communities from the mainstream economy. With the advent of democracy, the government has been faced with the mammoth task of driving transformation and inclusion in various sectors of the economy. Various pieces of legislation have been promulgated to give effect to this ideal. The Broad Based Black Economic Empowerment (BBBEE) Act with its associated regulations has Enterprise and Supplier development (ESD) as one of the five pillars underpinning the targeted areas for transformation in companies. Enterprise development is a key contributor to companies achieving a good score card rating as determined by the government of South Africa for various industries. This scoring also has advantages in terms of accessing government incentives as well as procurement opportunities for businesses with government. Companies therefore deploy capital for the development of businesses within their supply chains and also any other businesses whether or not they do business with them. This process of enterprise development funding is largely undefined and sees companies use various methods and criteria to deploy the capital with a myriad of outcomes all of which vary depending on the area of interest. The primary intent of the enterprise development funds is to create patient, free and sometimes affordable capital for the growth and sustainability of previously disadvantaged businesses in the South African context. Industries like manufacturing, in their nature are capital intensive and require huge capital outlays which then become a barrier to entry particularly for previously disadvantaged groupings like black people. The aim of the study is to identify key determinants that can unlock the growth and sustainability of black owned SMMEs in the manufacturing sector and also to understand the environment in which they operate. It is intended to assist policy makers, enterprise development practitioners, regulators and the beneficiaries of enterprise development on what can be done to ensure that this critical programme achieves its desired outcome. , Thesis (MA) -- Faculty of Business and Economic science, 2022
- Full Text:
- Date Issued: 2022-04
Evaluation of antimicrobial combination therapy options for the management of integron-mediated multidrug resistance in enterococcus species and acinetobacter baumannii from aquatic environment in the Eastern Cape Province, South Africa
- Authors: Ola, Adeniji Oluwaseun
- Date: 2022-04
- Subjects: Enterococcus , Aquatic biodiversity , Acinetobacter
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/27776 , vital:69467
- Description: Infectious diseases caused by multidrug-resistant MDR pathogens, such as Acinetobacter baumannii and Enterococcus spp., is an increasing worldwide problem. For treating these diseases, antibiotics are usually the first choice. But organisms develop resistance as a result of drug abuse, continuous use of antibiotics and release of antibiotics into the environment. These have prompted MDR's development, making even the most active drugs ineffective. Transposons, plasmids and integrons are the most effective mobile genetic elements that promote acquisition and spread of resistance determinants. Integrons carrying various arrays of resistance gene cassettes are principally helpful for epidemiological studies of these disease-causing organisms. Alternative treatments, such as using drugs in combination or with adjuvants and nanoparticles therapy, have been documented. Nanoparticles have the potential requirements for qualifying as antibacterial agents. In addition to their antimicrobial activities, nanoparticles can be used together with antibiotics for more enhanced antimicrobial activity In this study, Acinetobacter baumanni, Enterococcus faecium and Enterococcus faecalis were recovered from the aquatic environment in the Eastern Cape Province, South Africa with a standard microbiological method. Their antibiotic sensitivity testing was carried out using Kirby Bauer disk diffusion and microdilution methods. A high occurrence of class-1 integrons was discovered in MDR A. baumanni, with the internal variable containing aadA1, aadA5 and aadA2 genes, which confer resistance for streptomycin and spectinomycin, aac 6Ib for amikacin/ tobramycin and dfrA17 genes for trimethoprim. Similarly, class1 integron was detected in Enterococcus, without the presence of gene cassette. The checkerboard assay and time-kill assay were used to test for the effect of the combination of the antibiotic. The impact of colistin combined with quinolones (ciprofloxacin) with the Fractional inhibitory concentration index FICs 0.31 indicated synergistic effects against MDR A baumanni. However, when colistin was combined with meropenem and ceftazidime, additive effects with FIC, ranging from 0.52 to 1 were observed. In addition, a combination of gentamicin MIC 4 μgml with vancomycin MIC 256 μgml antibiotics against vancomycin-resistant Enterococcus faecalis showed antibacterial activity. In contrast, the combination of ciprofloxacin 1 μgml with Ampicillin 16 μgml antibiotics against Enterococcus faecalis showed a bacteriostatic effect. The initial inoculum declined by 100 percentage when gentamicin was combined with vancomycin at a concentration of 4 and 128 μgml MIC respectively, for about 2 h following the treatment for MDR E. faecium. Enterobacterial Repetitive Intergenic Consensus Polymerase Chain Reaction ERIC PCR analyses of the studied pathogens revealed great genetic diversity, suggesting the various sources of environmental contamination. Silver nanoparticles AgNPs and zinc oxide nanoparticles ZnO NPs were chemically synthesized using a precipitation method and characterized using energy dispersive Xray analysis EDX, scanning electron microscopy SEM, Fourier transforms infrared spectroscopic analysis FTIR and transmission electron microscopy TEM. The characterization results showed the synthesis of 43.37 nm and 21.03 nm nanoparticles of zinc oxide and silver origins, correspondingly, with distinct morphology, as revealed in TEM. The size, stability and functional groups of the nanoparticles produced were revealed using EDX and FTIR. Zinc oxide nanoparticles were cytotoxic against Vero cell lines at the tested concentrations, whereas AgNPs had no cytotoxic effect at lower concentrations. Acinetobacter baumanni, Enterococcus faecium and Enterococcus faecalis were with MIC in the range of 0.0390.078mgml for silver nanoparticles. Zinc oxide nanoparticles were explicitly active against Enterococcus species gram-positive with MIC of 1.25 5 mgml. Both studied nanoparticles exhibited profound synergistic and additive activities against all the investigated MDR pathogens. These findings demonstrate good antibacterial potential of the nanoparticles against drug-resistant strains and open a new arena of antimicrobials for medical treatment. , Thesis (MSc) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Ola, Adeniji Oluwaseun
- Date: 2022-04
- Subjects: Enterococcus , Aquatic biodiversity , Acinetobacter
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/27776 , vital:69467
- Description: Infectious diseases caused by multidrug-resistant MDR pathogens, such as Acinetobacter baumannii and Enterococcus spp., is an increasing worldwide problem. For treating these diseases, antibiotics are usually the first choice. But organisms develop resistance as a result of drug abuse, continuous use of antibiotics and release of antibiotics into the environment. These have prompted MDR's development, making even the most active drugs ineffective. Transposons, plasmids and integrons are the most effective mobile genetic elements that promote acquisition and spread of resistance determinants. Integrons carrying various arrays of resistance gene cassettes are principally helpful for epidemiological studies of these disease-causing organisms. Alternative treatments, such as using drugs in combination or with adjuvants and nanoparticles therapy, have been documented. Nanoparticles have the potential requirements for qualifying as antibacterial agents. In addition to their antimicrobial activities, nanoparticles can be used together with antibiotics for more enhanced antimicrobial activity In this study, Acinetobacter baumanni, Enterococcus faecium and Enterococcus faecalis were recovered from the aquatic environment in the Eastern Cape Province, South Africa with a standard microbiological method. Their antibiotic sensitivity testing was carried out using Kirby Bauer disk diffusion and microdilution methods. A high occurrence of class-1 integrons was discovered in MDR A. baumanni, with the internal variable containing aadA1, aadA5 and aadA2 genes, which confer resistance for streptomycin and spectinomycin, aac 6Ib for amikacin/ tobramycin and dfrA17 genes for trimethoprim. Similarly, class1 integron was detected in Enterococcus, without the presence of gene cassette. The checkerboard assay and time-kill assay were used to test for the effect of the combination of the antibiotic. The impact of colistin combined with quinolones (ciprofloxacin) with the Fractional inhibitory concentration index FICs 0.31 indicated synergistic effects against MDR A baumanni. However, when colistin was combined with meropenem and ceftazidime, additive effects with FIC, ranging from 0.52 to 1 were observed. In addition, a combination of gentamicin MIC 4 μgml with vancomycin MIC 256 μgml antibiotics against vancomycin-resistant Enterococcus faecalis showed antibacterial activity. In contrast, the combination of ciprofloxacin 1 μgml with Ampicillin 16 μgml antibiotics against Enterococcus faecalis showed a bacteriostatic effect. The initial inoculum declined by 100 percentage when gentamicin was combined with vancomycin at a concentration of 4 and 128 μgml MIC respectively, for about 2 h following the treatment for MDR E. faecium. Enterobacterial Repetitive Intergenic Consensus Polymerase Chain Reaction ERIC PCR analyses of the studied pathogens revealed great genetic diversity, suggesting the various sources of environmental contamination. Silver nanoparticles AgNPs and zinc oxide nanoparticles ZnO NPs were chemically synthesized using a precipitation method and characterized using energy dispersive Xray analysis EDX, scanning electron microscopy SEM, Fourier transforms infrared spectroscopic analysis FTIR and transmission electron microscopy TEM. The characterization results showed the synthesis of 43.37 nm and 21.03 nm nanoparticles of zinc oxide and silver origins, correspondingly, with distinct morphology, as revealed in TEM. The size, stability and functional groups of the nanoparticles produced were revealed using EDX and FTIR. Zinc oxide nanoparticles were cytotoxic against Vero cell lines at the tested concentrations, whereas AgNPs had no cytotoxic effect at lower concentrations. Acinetobacter baumanni, Enterococcus faecium and Enterococcus faecalis were with MIC in the range of 0.0390.078mgml for silver nanoparticles. Zinc oxide nanoparticles were explicitly active against Enterococcus species gram-positive with MIC of 1.25 5 mgml. Both studied nanoparticles exhibited profound synergistic and additive activities against all the investigated MDR pathogens. These findings demonstrate good antibacterial potential of the nanoparticles against drug-resistant strains and open a new arena of antimicrobials for medical treatment. , Thesis (MSc) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-04