Crossing shades
- Authors: Singh, Shareen
- Date: 2020
- Subjects: South African fiction (English) -- 21st century
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/145049 , vital:38404
- Description: This collection of stories draw on culture, history, memory, musings and imagination. The stories are set primarily in South Africa but includes travels to other countries. I explore journeys to different worlds and minds. I challenge the reader to see how place and time influence our ways of seeing, living and evolving. I use different forms and tones that resonate with the subjective nature of each creative piece. My writing includes formal prose as well as works that experiment with fragments, vignettes and flash fiction.
- Full Text:
- Date Issued: 2020
- Authors: Singh, Shareen
- Date: 2020
- Subjects: South African fiction (English) -- 21st century
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/145049 , vital:38404
- Description: This collection of stories draw on culture, history, memory, musings and imagination. The stories are set primarily in South Africa but includes travels to other countries. I explore journeys to different worlds and minds. I challenge the reader to see how place and time influence our ways of seeing, living and evolving. I use different forms and tones that resonate with the subjective nature of each creative piece. My writing includes formal prose as well as works that experiment with fragments, vignettes and flash fiction.
- Full Text:
- Date Issued: 2020
Curriculating powerful knowledge for public managers and administrators
- McKenna, Sioux, Harran, Marcelle, Lück, Jacqueline
- Authors: McKenna, Sioux , Harran, Marcelle , Lück, Jacqueline
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187160 , vital:44575 , xlink:href="https://doi.org/10.1080/18146627.2019.1652103"
- Description: Public Management and Public Administration are important professions for an emerging democracy such as South Africa. They operate as the interface between state and public and are responsible for enacting many of the government's policies and social initiatives. Concerns about a lack of capacity in the sector suggest that those in these roles may be unable to meet the demands of the workplace. This article reports on a study that responded to calls for the curriculum to address such concerns by interrogating the knowledge structures of Public Management and Public Administration programmes in higher education. Interviews, textbooks and course guides were analysed to illuminate the forms of knowledge being legitimated in curricula. The study found that the focus on knowledge, skills and processes might be at the expense of a focus on the development of particular attributes or dispositions in the knowers. Furthermore, the knowledge level focus was limited in that it was highly contextualised and “light” on theory, raising questions about the acquisition of powerful knowledge needed for good governance and critical engagement in the public sector. The study recommends that both programmes include more conceptual knowledge; exposure to critical powerful forms of knowledge; and the development of particular attributes and dispositions.
- Full Text:
- Date Issued: 2020
- Authors: McKenna, Sioux , Harran, Marcelle , Lück, Jacqueline
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187160 , vital:44575 , xlink:href="https://doi.org/10.1080/18146627.2019.1652103"
- Description: Public Management and Public Administration are important professions for an emerging democracy such as South Africa. They operate as the interface between state and public and are responsible for enacting many of the government's policies and social initiatives. Concerns about a lack of capacity in the sector suggest that those in these roles may be unable to meet the demands of the workplace. This article reports on a study that responded to calls for the curriculum to address such concerns by interrogating the knowledge structures of Public Management and Public Administration programmes in higher education. Interviews, textbooks and course guides were analysed to illuminate the forms of knowledge being legitimated in curricula. The study found that the focus on knowledge, skills and processes might be at the expense of a focus on the development of particular attributes or dispositions in the knowers. Furthermore, the knowledge level focus was limited in that it was highly contextualised and “light” on theory, raising questions about the acquisition of powerful knowledge needed for good governance and critical engagement in the public sector. The study recommends that both programmes include more conceptual knowledge; exposure to critical powerful forms of knowledge; and the development of particular attributes and dispositions.
- Full Text:
- Date Issued: 2020
Cyber Security Responsibilization: an evaluation of the intervention approaches adopted by the Five Eyes Countries and China
- Renaud, Karen, Orgeron, Craig, Warkentin, Merrill, French, P Edward
- Authors: Renaud, Karen , Orgeron, Craig , Warkentin, Merrill , French, P Edward
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/149806 , vital:38885 , https://0-doi.org.wam.seals.ac.za/10.1111/puar.13210
- Description: Governments can intervene to a greater or lesser extent in managing the risks that citizens face. They can adopt a maximal intervention approach (e .g. COVID‐19) or a hands‐off approach (e .g ., unemployment) , effectively “responsibilizing” their citizens. To manage the cyber risk, governments publish cyber‐related policies. This article examines the intervention stances the governments adopt in supporting individual citizens managing their personal cyber risk. The authors pinpoint the cyber‐related responsibilities that several governments espouse, applying a “responsibilization” analysis. Those applying to citizens are identified, thereby revealing the governments' cyber‐related intervention stance. The analysis reveals that most governments adopt a minimal cyber‐related intervention stance in supporting their citizens. Given the increasing number of successful cyber attacks on individuals, it seems time for the consequences of this stance to be acknowledged and reconsidered. The authors argue that governments should support individual citizens more effectively in dealing with cyber threats.
- Full Text:
- Date Issued: 2020
- Authors: Renaud, Karen , Orgeron, Craig , Warkentin, Merrill , French, P Edward
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/149806 , vital:38885 , https://0-doi.org.wam.seals.ac.za/10.1111/puar.13210
- Description: Governments can intervene to a greater or lesser extent in managing the risks that citizens face. They can adopt a maximal intervention approach (e .g. COVID‐19) or a hands‐off approach (e .g ., unemployment) , effectively “responsibilizing” their citizens. To manage the cyber risk, governments publish cyber‐related policies. This article examines the intervention stances the governments adopt in supporting individual citizens managing their personal cyber risk. The authors pinpoint the cyber‐related responsibilities that several governments espouse, applying a “responsibilization” analysis. Those applying to citizens are identified, thereby revealing the governments' cyber‐related intervention stance. The analysis reveals that most governments adopt a minimal cyber‐related intervention stance in supporting their citizens. Given the increasing number of successful cyber attacks on individuals, it seems time for the consequences of this stance to be acknowledged and reconsidered. The authors argue that governments should support individual citizens more effectively in dealing with cyber threats.
- Full Text:
- Date Issued: 2020
Cytotoxicity of triterpenoids from Clerodendrum glabrum against triple negative breast cancer cells in vitro:
- Teclegeorgish, Zecarias W, Mokgalaka, Ntebogeng S, Vukea, Nyeleti, de la Mare, Jo-Anne, Tembu, Vuyelwa J
- Authors: Teclegeorgish, Zecarias W , Mokgalaka, Ntebogeng S , Vukea, Nyeleti , de la Mare, Jo-Anne , Tembu, Vuyelwa J
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/161511 , vital:40634 , https://doi.org/10.1016/j.sajb.2020.07.009
- Description: Clerodendrum glabrum is an indigenous medicinal plant that is used to treat cough, cold, sore throat and chest complaints. The stem bark of Clerodendrum glabrum afforded four tritepenoids namely, 3β-olean-12-en-3-yl palmitate (β-amyrin palmitate), (1), 3β hydroxy 5-glutinene (glutinol), (2), 3β-lup-20(29)-en-3-palmitate (Lupeol-3-palmitate), (3), 3β-lup-20(29)-en-3-ol (lupeol) (4) and one common phytosterol (stigmasterol) (5). The structures were established on the basis of their spectroscopic analysis. The compounds were screened for cytotoxicity against the HCC70 triple negative breast cancer (TNBC), MCF-7 hormone receptor positive breast cancer and MCF-12A non-cancerous mammary epithelial cell lines.
- Full Text:
- Date Issued: 2020
- Authors: Teclegeorgish, Zecarias W , Mokgalaka, Ntebogeng S , Vukea, Nyeleti , de la Mare, Jo-Anne , Tembu, Vuyelwa J
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/161511 , vital:40634 , https://doi.org/10.1016/j.sajb.2020.07.009
- Description: Clerodendrum glabrum is an indigenous medicinal plant that is used to treat cough, cold, sore throat and chest complaints. The stem bark of Clerodendrum glabrum afforded four tritepenoids namely, 3β-olean-12-en-3-yl palmitate (β-amyrin palmitate), (1), 3β hydroxy 5-glutinene (glutinol), (2), 3β-lup-20(29)-en-3-palmitate (Lupeol-3-palmitate), (3), 3β-lup-20(29)-en-3-ol (lupeol) (4) and one common phytosterol (stigmasterol) (5). The structures were established on the basis of their spectroscopic analysis. The compounds were screened for cytotoxicity against the HCC70 triple negative breast cancer (TNBC), MCF-7 hormone receptor positive breast cancer and MCF-12A non-cancerous mammary epithelial cell lines.
- Full Text:
- Date Issued: 2020
Data on microhardness and structural analysis of friction stir spot welded lap joints of AA5083-H116
- Esther T. Akinlabi, Ayuba S. Osinubi b, Nkosinathi Madushele b, Stephen A. Akinlabi c, Omolayo M. Ikumapayi d,∗
- Authors: Esther T. Akinlabi , Ayuba S. Osinubi b , Nkosinathi Madushele b , Stephen A. Akinlabi c , Omolayo M. Ikumapayi d,∗
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/3260 , vital:43286 , https://www.sciencedirect.com/science/article/pii/S2352340920314669
- Description: Friction stir spot welding (FSSW) was established to compete reasonably with the reverting, bolting, adhesive bonding as well as resistance spot welding (RSW) which have been used in the past for lap joining in automobile, aerospace, marine, railways, defence and shipbuilding industries. The use of these ancient and conventional joining techniques had led to increasing material cost, installation labour, and additional weight in the aircraft, shipbuilding, and other areas of applications. All these are disadvantages that can be overcome using FSSW. This research work carried out friction stir spot welding on 5058-H116 aluminium alloy by employing rotational speed in the step of 300 rpm ranges from 600 rpm to 1200 rpm with a no travel speed. It was noted that the dwell times were in the step of 5 s varying from 5 s to 15 s while the tool plunge rate was maintained at 30 mm/min. In this dataset, a cylindrical tapered rotating H13 Hot-working steel tool was used with a probe length of 5 mm and probe diameter of 6 mm, it has a shoulder diameter of 18 mm. The tool penetration depth (plunge) was maintained at 0.2 mm and the tool tilt angle at 2°. Structural integrity was car-ried out using Rigaku ultima IV multifunctional X-ray diffractometer (XRD) with a scan voltage of 40 kV and scan current of 30 mA. This was used to determine crystallite sizes, peak intensity, d-spacing, full width at half maximum intensity (FWHM) of the diffraction peak. TH713 digital microhardness equipment with diamond indenter was used for microhardness data acquisition following ASTM E92–82 standard test. The average Vickers hardness data values at different zones of the spot-welds were captured and presented.
- Full Text:
- Date Issued: 2020
Data on microhardness and structural analysis of friction stir spot welded lap joints of AA5083-H116
- Authors: Esther T. Akinlabi , Ayuba S. Osinubi b , Nkosinathi Madushele b , Stephen A. Akinlabi c , Omolayo M. Ikumapayi d,∗
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/3260 , vital:43286 , https://www.sciencedirect.com/science/article/pii/S2352340920314669
- Description: Friction stir spot welding (FSSW) was established to compete reasonably with the reverting, bolting, adhesive bonding as well as resistance spot welding (RSW) which have been used in the past for lap joining in automobile, aerospace, marine, railways, defence and shipbuilding industries. The use of these ancient and conventional joining techniques had led to increasing material cost, installation labour, and additional weight in the aircraft, shipbuilding, and other areas of applications. All these are disadvantages that can be overcome using FSSW. This research work carried out friction stir spot welding on 5058-H116 aluminium alloy by employing rotational speed in the step of 300 rpm ranges from 600 rpm to 1200 rpm with a no travel speed. It was noted that the dwell times were in the step of 5 s varying from 5 s to 15 s while the tool plunge rate was maintained at 30 mm/min. In this dataset, a cylindrical tapered rotating H13 Hot-working steel tool was used with a probe length of 5 mm and probe diameter of 6 mm, it has a shoulder diameter of 18 mm. The tool penetration depth (plunge) was maintained at 0.2 mm and the tool tilt angle at 2°. Structural integrity was car-ried out using Rigaku ultima IV multifunctional X-ray diffractometer (XRD) with a scan voltage of 40 kV and scan current of 30 mA. This was used to determine crystallite sizes, peak intensity, d-spacing, full width at half maximum intensity (FWHM) of the diffraction peak. TH713 digital microhardness equipment with diamond indenter was used for microhardness data acquisition following ASTM E92–82 standard test. The average Vickers hardness data values at different zones of the spot-welds were captured and presented.
- Full Text:
- Date Issued: 2020
Dataset and ANN model prediction of performance of graphene nanolubricant with R600a in domestic refrigerator system
- Taiwo, Babarinde, Stephen, Akinlabi, Daniel Makundwaneyi, Madyira, Ekundayo, Funmilayo M, Paul Adeola, Adedeji
- Authors: Taiwo, Babarinde , Stephen, Akinlabi , Daniel Makundwaneyi, Madyira , Ekundayo, Funmilayo M , Paul Adeola, Adedeji
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/3139 , vital:43150 , (https://www.sciencedirect.com/science/article/pii/S2352340920309926)
- Description: This work evaluated the steady state performance of R600a in the base lubricant and graphene nanolubricant. The measuring instruments required and their uncertainties were provided, step by step method and procedures for preparation of graphene nanolubricant concentration and substituting it with the base lubricant in domestic refrigerator system are described. The system temperatures data was captured at the inlet and outlet of the system components. Also, the pressures data was recorded at the compressor inlet and outlet. The data was recorded for 3 h at 30 min interval at an ambient temperature of 27 °C. The experimental dataset, Artificial Neural Network (ANN) training and testing dataset are provided. The artificial intelligence approach of ANN model to predict the performance of graphene nanolubricant in domestic refrigerator is explained. Also, the ANN model prediction statistical performance metrics such as Root Mean Square Error (RMSE) and Mean Absolute Deviation (MAD), Mean Absolute Percentage Error (MAPE) and coefficient of determination (R2) are also provided. The data is useful to researchers in the field of refrigeration and energy efficiency materials, for replacing nanolubricant with the base lubricant in refrigerator systems. The data can be reuse for simulation and modelling vapour compression energy system.
- Full Text:
- Date Issued: 2020
- Authors: Taiwo, Babarinde , Stephen, Akinlabi , Daniel Makundwaneyi, Madyira , Ekundayo, Funmilayo M , Paul Adeola, Adedeji
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/3139 , vital:43150 , (https://www.sciencedirect.com/science/article/pii/S2352340920309926)
- Description: This work evaluated the steady state performance of R600a in the base lubricant and graphene nanolubricant. The measuring instruments required and their uncertainties were provided, step by step method and procedures for preparation of graphene nanolubricant concentration and substituting it with the base lubricant in domestic refrigerator system are described. The system temperatures data was captured at the inlet and outlet of the system components. Also, the pressures data was recorded at the compressor inlet and outlet. The data was recorded for 3 h at 30 min interval at an ambient temperature of 27 °C. The experimental dataset, Artificial Neural Network (ANN) training and testing dataset are provided. The artificial intelligence approach of ANN model to predict the performance of graphene nanolubricant in domestic refrigerator is explained. Also, the ANN model prediction statistical performance metrics such as Root Mean Square Error (RMSE) and Mean Absolute Deviation (MAD), Mean Absolute Percentage Error (MAPE) and coefficient of determination (R2) are also provided. The data is useful to researchers in the field of refrigeration and energy efficiency materials, for replacing nanolubricant with the base lubricant in refrigerator systems. The data can be reuse for simulation and modelling vapour compression energy system.
- Full Text:
- Date Issued: 2020
Dataset of experimental and adaptive neuro-fuzzy inference system (ANFIS) model prediction of R600a/MWCNT nanolubricant in a vapour compression system
- Babarinde, T O, Akinlabi, S A, Madyira, D M, Ekundayo, F M, Adedeji, P A
- Authors: Babarinde, T O , Akinlabi, S A , Madyira, D M , Ekundayo, F M , Adedeji, P A
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/3248 , vital:43283 , https://www.sciencedirect.com/science/article/pii/S2352340920312105
- Description: This research paper assessed the performance of R600a with the base lubricant and Multi-walled Carbon Nanotube (MWCNT) nanolubricant at steady state. It describes the instruments required for measurement of the data parameter and its uncertainties, steps involved in preparing and replacing the MWCNT nanolubricant concentration with base lubricant in vapour compression refrigeration. The system’s temperature data was collected at the components inlets and outlets. Pressure data was also registered at the compressor outlet and inlet. The data was captured at 27 °C ambient temperature at an interval of 30 min for 300 min. The experiment includes the experimental data collection, Adaptive Neuro-Fuzzy Inference System (ANFIS) training and testing dataset. The use of ANFIS model is explained in predicting the efficiency of MWCNT nanolubricant in a vapour compression refrigerator system. The ANFIS model also provides statistical output measures such as Root Mean Square Error (RMSE) and Mean Absolute Deviation (MAD), Mean Absolute Percentage Error (MAPE), and determination coefficient (R2). The data is useful and important for replacing MWCNT nanolubricant with base lubricant in a vapour compression refrigeration system for researchers in the specialisation of energy-efficient materials in refrigeration. The data present can be reused for vapour compression refrigeration systems simulation and modelling.
- Full Text:
- Date Issued: 2020
- Authors: Babarinde, T O , Akinlabi, S A , Madyira, D M , Ekundayo, F M , Adedeji, P A
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/3248 , vital:43283 , https://www.sciencedirect.com/science/article/pii/S2352340920312105
- Description: This research paper assessed the performance of R600a with the base lubricant and Multi-walled Carbon Nanotube (MWCNT) nanolubricant at steady state. It describes the instruments required for measurement of the data parameter and its uncertainties, steps involved in preparing and replacing the MWCNT nanolubricant concentration with base lubricant in vapour compression refrigeration. The system’s temperature data was collected at the components inlets and outlets. Pressure data was also registered at the compressor outlet and inlet. The data was captured at 27 °C ambient temperature at an interval of 30 min for 300 min. The experiment includes the experimental data collection, Adaptive Neuro-Fuzzy Inference System (ANFIS) training and testing dataset. The use of ANFIS model is explained in predicting the efficiency of MWCNT nanolubricant in a vapour compression refrigerator system. The ANFIS model also provides statistical output measures such as Root Mean Square Error (RMSE) and Mean Absolute Deviation (MAD), Mean Absolute Percentage Error (MAPE), and determination coefficient (R2). The data is useful and important for replacing MWCNT nanolubricant with base lubricant in a vapour compression refrigeration system for researchers in the specialisation of energy-efficient materials in refrigeration. The data present can be reused for vapour compression refrigeration systems simulation and modelling.
- Full Text:
- Date Issued: 2020
Debunking the myth of lack of vocabulary for teaching content knowledge in primary schools: exploring terminology for science in Ekegusii of Kenya
- Authors: Mose, Peter
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/150095 , vital:38939 , DOI: 10.1080/02572117.2020.1733827
- Description: The language-in-education policy to teach in mother tongues at lower primary level is not adhered to by classroom teachers in Kenya due to, among other reasons, lack of content terminology. The purpose of this study was to demonstrate that mother tongues can be used to teach science up to the end of grade three, considering the nature of topics for this level and other extra-classroom realities. Our research objectives were to examine the nature and content of science topics and sub-topics from grade one to grade three; examine conceptual and technical terms in grade one to grade three science textbooks; describe the Ekegusii equivalents of these terms; and explain the feasibility of teaching science in Ekegusii up to the end of grade three.
- Full Text:
- Date Issued: 2020
- Authors: Mose, Peter
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/150095 , vital:38939 , DOI: 10.1080/02572117.2020.1733827
- Description: The language-in-education policy to teach in mother tongues at lower primary level is not adhered to by classroom teachers in Kenya due to, among other reasons, lack of content terminology. The purpose of this study was to demonstrate that mother tongues can be used to teach science up to the end of grade three, considering the nature of topics for this level and other extra-classroom realities. Our research objectives were to examine the nature and content of science topics and sub-topics from grade one to grade three; examine conceptual and technical terms in grade one to grade three science textbooks; describe the Ekegusii equivalents of these terms; and explain the feasibility of teaching science in Ekegusii up to the end of grade three.
- Full Text:
- Date Issued: 2020
Decent work and informal employment: the case of Bulawayo Metropolitan Province (Central Business District) Zimbabwe
- Authors: Bob, Shaka Keny
- Date: 2020
- Subjects: Labor -- Zimbabwe , Informal sector (Economics) -- Zimbabwe , Job creation -- Zimbabwe , Poor -- Zimbabwe -- Employment , Labor policy -- Zimbabwe , Football coaches -- South Africa
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/115241 , vital:34104
- Description: Zimbabwe, similar to other developing countries experiences a high level of informal employment. However, most informal jobs are situated in very poor working conditions and are characterised by decent work deficits. Despite the fact that various studies have shown the importance of the informal economy in that it provides livelihood earning opportunities for the majority of people in the Global South, it has remained a largely forgotten sector in policy making in most countries. It is, therefore, important that informal work be taken seriously and efforts must be made to improve working conditions for the urban working poor in the developing world. The purpose of this study is to investigate on the self-reported experiences of informal workers to understand their perspectives surrounding the concept of decent work in the Zimbabwean context. The case study is the Bulawayo metropolitan province, and this study targeted informal workers who trade within the central business district. The study also aimed to measure the decent work deficit scores between two economic sectors (food and clothing traders). This was done by testing the suitability of the Edward Webster Decent Work Deficit Index as a methodology of measuring decent work at a micro level. The analysis is based on a mixed methods study which was carried out through the use of a semi-structured survey. The study revealed that decent work for the sampled informal workers meant work related improvements, insurances and risk management, right of expression and business advancement skills which closely resembles the International Labour Organisation's conceptualisation of decent work. The study also highlighted that childcare assistance and disability insurance are concepts which remained excluded in the current conceptualisation of decent work. The thesis offers a new policy angle which shows that to promote decent work the concept of heterogeneity must be adopted because inequalities persist within the informal economy. The study also suggested that the Edward Webster Decent Work Deficit Index can be used as an appropriate methodology of monitoring the progress towards achieving decent work at the micro level i.e. industry or individual level. This is because since the formation of the decent work concept; the International Labour Organisation has only provided a methodology of how to measure the progress of decent work at the county level. The survey findings revealed that food vendors scored more poorly on the decent work deficit index compared to the clothing traders. The study also identified that food vendors and clothing traders are faced with different challenges which suggests that policy makers must take that into consideration when attempting to design policies or programmes which are aimed at assisting informal workers.
- Full Text:
- Date Issued: 2020
- Authors: Bob, Shaka Keny
- Date: 2020
- Subjects: Labor -- Zimbabwe , Informal sector (Economics) -- Zimbabwe , Job creation -- Zimbabwe , Poor -- Zimbabwe -- Employment , Labor policy -- Zimbabwe , Football coaches -- South Africa
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/115241 , vital:34104
- Description: Zimbabwe, similar to other developing countries experiences a high level of informal employment. However, most informal jobs are situated in very poor working conditions and are characterised by decent work deficits. Despite the fact that various studies have shown the importance of the informal economy in that it provides livelihood earning opportunities for the majority of people in the Global South, it has remained a largely forgotten sector in policy making in most countries. It is, therefore, important that informal work be taken seriously and efforts must be made to improve working conditions for the urban working poor in the developing world. The purpose of this study is to investigate on the self-reported experiences of informal workers to understand their perspectives surrounding the concept of decent work in the Zimbabwean context. The case study is the Bulawayo metropolitan province, and this study targeted informal workers who trade within the central business district. The study also aimed to measure the decent work deficit scores between two economic sectors (food and clothing traders). This was done by testing the suitability of the Edward Webster Decent Work Deficit Index as a methodology of measuring decent work at a micro level. The analysis is based on a mixed methods study which was carried out through the use of a semi-structured survey. The study revealed that decent work for the sampled informal workers meant work related improvements, insurances and risk management, right of expression and business advancement skills which closely resembles the International Labour Organisation's conceptualisation of decent work. The study also highlighted that childcare assistance and disability insurance are concepts which remained excluded in the current conceptualisation of decent work. The thesis offers a new policy angle which shows that to promote decent work the concept of heterogeneity must be adopted because inequalities persist within the informal economy. The study also suggested that the Edward Webster Decent Work Deficit Index can be used as an appropriate methodology of monitoring the progress towards achieving decent work at the micro level i.e. industry or individual level. This is because since the formation of the decent work concept; the International Labour Organisation has only provided a methodology of how to measure the progress of decent work at the county level. The survey findings revealed that food vendors scored more poorly on the decent work deficit index compared to the clothing traders. The study also identified that food vendors and clothing traders are faced with different challenges which suggests that policy makers must take that into consideration when attempting to design policies or programmes which are aimed at assisting informal workers.
- Full Text:
- Date Issued: 2020
Decolonisation as a spatial question: the student accommodation crisis and Higher Education transformation
- Mzileni, Pedro, Mkhize, Nomalanga
- Authors: Mzileni, Pedro , Mkhize, Nomalanga
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/156378 , vital:39984 , DOI: 10.1080/21528586.2020.1733649
- Description: Debates on epistemological decolonisation have focused on curriculum issues. There has not been sufficient analysis of how questions of decolonisation are shaped by other factors, such as the very spatial location of universities. This article argues that the colonial nature of the university in South Africa is directly linked spatially to the historic land question of dispossession in South Africa. Historically, South African universities came to be fixed as physical and cultural elements of towns and cities based on the broader trajectory of settler-colonialism and apartheid urban development, segregation and the Group Areas logic of the apartheid state.
- Full Text:
- Date Issued: 2020
- Authors: Mzileni, Pedro , Mkhize, Nomalanga
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/156378 , vital:39984 , DOI: 10.1080/21528586.2020.1733649
- Description: Debates on epistemological decolonisation have focused on curriculum issues. There has not been sufficient analysis of how questions of decolonisation are shaped by other factors, such as the very spatial location of universities. This article argues that the colonial nature of the university in South Africa is directly linked spatially to the historic land question of dispossession in South Africa. Historically, South African universities came to be fixed as physical and cultural elements of towns and cities based on the broader trajectory of settler-colonialism and apartheid urban development, segregation and the Group Areas logic of the apartheid state.
- Full Text:
- Date Issued: 2020
Decolonisation of nature in towns and cities of South Africa:
- Cocks, Michelle L, Shackleton, Charlie M, Walsh, Lindsey S, Haynes, Duncan, Manyani, Amanda, Radebe, Dennis
- Authors: Cocks, Michelle L , Shackleton, Charlie M , Walsh, Lindsey S , Haynes, Duncan , Manyani, Amanda , Radebe, Dennis
- Date: 2020
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/175720 , vital:42618 , ISBN 9781000215182
- Description: Ways of conceptualising the world around us and being in this world are defined by an ontological understanding. Within a Eurocentric ideological understanding, nature is positioned to be opposite to culture, ie, nature is considered as “other” of which humans are not a part. Modernity is perceived as the antithesis of nature as processes of production, metabolism and expansion of modern cities represent attempts to tame and control nature. In turn, cities have become viewed as agents of development and change, promoting ideals of progress, thinking and innovation (Jayne 2005). Eurocentric ideals are framed as the forerunners of these processes and have come to influence international policies, global governance, alliances and networks which have in turn informed the design and governance of cities and influenced all aspects of urban liveability (Bouteligier 2011), including how urban natures are defined and constructed and the wellbeing benefits derived from them.
- Full Text:
- Date Issued: 2020
- Authors: Cocks, Michelle L , Shackleton, Charlie M , Walsh, Lindsey S , Haynes, Duncan , Manyani, Amanda , Radebe, Dennis
- Date: 2020
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/175720 , vital:42618 , ISBN 9781000215182
- Description: Ways of conceptualising the world around us and being in this world are defined by an ontological understanding. Within a Eurocentric ideological understanding, nature is positioned to be opposite to culture, ie, nature is considered as “other” of which humans are not a part. Modernity is perceived as the antithesis of nature as processes of production, metabolism and expansion of modern cities represent attempts to tame and control nature. In turn, cities have become viewed as agents of development and change, promoting ideals of progress, thinking and innovation (Jayne 2005). Eurocentric ideals are framed as the forerunners of these processes and have come to influence international policies, global governance, alliances and networks which have in turn informed the design and governance of cities and influenced all aspects of urban liveability (Bouteligier 2011), including how urban natures are defined and constructed and the wellbeing benefits derived from them.
- Full Text:
- Date Issued: 2020
Decorated titania fibers as photocatalysts for hydrogen generation and organic matter degradation
- Mapukata, Sivuyisiwe, Hainer, Andrew S, Lanterna, Anabel E, Scaiano, Juan C, Nyokong, Tebello
- Authors: Mapukata, Sivuyisiwe , Hainer, Andrew S , Lanterna, Anabel E , Scaiano, Juan C , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186573 , vital:44513 , xlink:href="https://doi.org/10.1016/j.jphotochem.2019.112185"
- Description: Heterogenous photocatalysts based on electrospun fibers composed of polyvinylpyrrolidone and titanium propoxide were prepared and heated at 500, 750 and 950 °C to obtain anatase and rutile fibers. The fibers were then decorated with Pd and Co nanoparticles as well as a symmetrical zinc phthalocyanine (Pc). The fibrous materials obtained have a paper-like macroscopic appearance allowing for easy handling and separation. The photocatalytic activities of the new materials were evaluated for the generation of H2 upon UV (368 nm) or visible (630 nm) light excitation. Depending on the heat treatment or the post-synthetic decoration method, the materials show higher, or similar, activity compared to P25-TiO2, with superior ease of separation. The catalysts showed ability to degrade organic matter, with MeOH used as a model compound. This is of considerable importance for potential water treatment applications that will require flow-compatible materials.
- Full Text:
- Date Issued: 2020
- Authors: Mapukata, Sivuyisiwe , Hainer, Andrew S , Lanterna, Anabel E , Scaiano, Juan C , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186573 , vital:44513 , xlink:href="https://doi.org/10.1016/j.jphotochem.2019.112185"
- Description: Heterogenous photocatalysts based on electrospun fibers composed of polyvinylpyrrolidone and titanium propoxide were prepared and heated at 500, 750 and 950 °C to obtain anatase and rutile fibers. The fibers were then decorated with Pd and Co nanoparticles as well as a symmetrical zinc phthalocyanine (Pc). The fibrous materials obtained have a paper-like macroscopic appearance allowing for easy handling and separation. The photocatalytic activities of the new materials were evaluated for the generation of H2 upon UV (368 nm) or visible (630 nm) light excitation. Depending on the heat treatment or the post-synthetic decoration method, the materials show higher, or similar, activity compared to P25-TiO2, with superior ease of separation. The catalysts showed ability to degrade organic matter, with MeOH used as a model compound. This is of considerable importance for potential water treatment applications that will require flow-compatible materials.
- Full Text:
- Date Issued: 2020
Deep phylogeographic structure may indicate cryptic species within the Sparid genus Spondyliosoma:
- McKeown, Niall J, Gwilliam, Michael P, Healey, Amy J E, Skujina, Ilze, Potts, Warren M, Sauer, Warwick H H, Shaw, Paul W
- Authors: McKeown, Niall J , Gwilliam, Michael P , Healey, Amy J E , Skujina, Ilze , Potts, Warren M , Sauer, Warwick H H , Shaw, Paul W
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/158085 , vital:40147 , DOI: 10.1111/jfb.14316
- Description: Two geographically nonoverlapping species are currently described within the sparid genus Spondyliosoma: Spondyliosoma cantharus (Black Seabream) occurring across Mediterranean and eastern Atlantic waters from NW Europe to Angola and S. emarginatum (Steentjie) considered endemic to southern Africa. To address prominent knowledge gaps this study investigated range‐wide phylogeographic structure across both species. Mitochondrial DNA sequences revealed deep phylogeographic structuring with four regionally partitioned reciprocally monophyletic clades, a Mediterranean clade and three more closely related Atlantic clades [NE Atlantic, Angola and South Africa (corresponding to S. emarginatum)]. Divergence and distribution of the lineages reflects survival in, and expansion from, disjunct glacial refuge areas. Cytonuclear differentiation of S. emarginatum supports its validity as a distinct species endemic to South African waters.
- Full Text:
- Date Issued: 2020
- Authors: McKeown, Niall J , Gwilliam, Michael P , Healey, Amy J E , Skujina, Ilze , Potts, Warren M , Sauer, Warwick H H , Shaw, Paul W
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/158085 , vital:40147 , DOI: 10.1111/jfb.14316
- Description: Two geographically nonoverlapping species are currently described within the sparid genus Spondyliosoma: Spondyliosoma cantharus (Black Seabream) occurring across Mediterranean and eastern Atlantic waters from NW Europe to Angola and S. emarginatum (Steentjie) considered endemic to southern Africa. To address prominent knowledge gaps this study investigated range‐wide phylogeographic structure across both species. Mitochondrial DNA sequences revealed deep phylogeographic structuring with four regionally partitioned reciprocally monophyletic clades, a Mediterranean clade and three more closely related Atlantic clades [NE Atlantic, Angola and South Africa (corresponding to S. emarginatum)]. Divergence and distribution of the lineages reflects survival in, and expansion from, disjunct glacial refuge areas. Cytonuclear differentiation of S. emarginatum supports its validity as a distinct species endemic to South African waters.
- Full Text:
- Date Issued: 2020
Default in payment, an application of statistical learning techniques
- Authors: Gcakasi, Lulama
- Date: 2020
- Subjects: Credit -- South Africa -- Risk assessment , Risk management -- Statistical methods -- South Africa , Credit -- Management -- Statistical methods , Commercial statistics
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/141547 , vital:37984
- Description: The ability of financial institutions to detect whether a customer will default on their credit card payment is essential for its profitability. To that effect, financial institutions have credit scoring systems in place to be able to estimate the credit risk associated with a customer. Various classification models are used to develop credit scoring systems such as k-nearest neighbours, logistic regression and classification trees. This study aims to assess the performance of different classification models on the prediction of credit card payment default. Credit data is usually of high dimension and as a result dimension reduction techniques, namely principal component analysis and linear discriminant analysis, are used in this study as a means to improve model performance. Two classification models are used, namely neural networks and support vector machines. Model performance is evaluated using accuracy and area under the curve (AUC). The neuarl network classifier performed better than the support vector machine classifier as it produced higher accuracy rates and AUC values. Dimension reduction techniques were not effective in improving model performance but did result in less computationally expensive models.
- Full Text:
- Date Issued: 2020
- Authors: Gcakasi, Lulama
- Date: 2020
- Subjects: Credit -- South Africa -- Risk assessment , Risk management -- Statistical methods -- South Africa , Credit -- Management -- Statistical methods , Commercial statistics
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/141547 , vital:37984
- Description: The ability of financial institutions to detect whether a customer will default on their credit card payment is essential for its profitability. To that effect, financial institutions have credit scoring systems in place to be able to estimate the credit risk associated with a customer. Various classification models are used to develop credit scoring systems such as k-nearest neighbours, logistic regression and classification trees. This study aims to assess the performance of different classification models on the prediction of credit card payment default. Credit data is usually of high dimension and as a result dimension reduction techniques, namely principal component analysis and linear discriminant analysis, are used in this study as a means to improve model performance. Two classification models are used, namely neural networks and support vector machines. Model performance is evaluated using accuracy and area under the curve (AUC). The neuarl network classifier performed better than the support vector machine classifier as it produced higher accuracy rates and AUC values. Dimension reduction techniques were not effective in improving model performance but did result in less computationally expensive models.
- Full Text:
- Date Issued: 2020
Design ethnography: methodological considerations for rebalancing socio-technical phenomena in CMS performativity
- Authors: Jordaan, Leandra
- Date: 2020
- Subjects: Database management -- Social aspects , Information technology -- Social aspects , Management information systems -- Social aspects , Database management -- Philosophy , Information technology -- Philosophy , Management information systems -- Philosophy
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/164781 , vital:41164
- Description: As a practitioner, I had been part of two Content Management System (CMS) Projects in a particular setting that did not deliver on the expected outcomes. The expected outcomes of the projects included streamlined processes, better access to information, functionalities to drive engagement, reduced time searching for information, and improved reusability of content. As I began to reflect on the projects, a certain discomfort developed when the social aspect was ignored in favour of the technological. I sought a better understanding, but I was unaware of the fact at first. The techno-centricity as a concept found in literature and my experience as content management (CM) practitioner – together informed my interest in rebalancing the social and the technological. Thus, I focused on conduct in performing of tasks and emphasised attention on the practices of experts who gave insight into context of CM and use. The research participants are communication practitioners who have the responsibility to communicate internally and externally on behalf of a publicly-funded university in South Africa. Guided by the abductive argument and literature, the key themes for the research focused on technology, individuals and the organisation. The focus on technology (CMS as a subfield of Information Systems) began with my involvement in two CMS Projects. What came to the fore was that the practitioner perspective, and thus their experiential knowledge are neglected in research and that it may be an over-emphasis on techno-centrism in CMS research. I sought to better balance the social and technological aspects. The second focus on individuals (communication practitioners) was to value the stakeholder who was considered representative of the worldviews of the community. I sought to support corporate communication practices in the task of relationship building with stakeholders. The findings showed that the culture of informatio sharing was low at the University. The third focus on the organisation (the University) was to prioritise the success of the communication undertaken by the University. I interrogated the role of power. I demonstrated how the role of power could be seen as productive and positive in the context of HE, the social reality of CUT, and this IS research itself. I positioned the research as interpretivistic. I used hermeneutics as a mode of analysis because as researcher-practitioner, I am part of the social reality of the research. A safeguard against my subjectivity was the use of Phronesis as an orientation to knowledge. An organisation with a shared understanding of ethics and values will balance instrumental rationality (scientific and technical reasoning) with value-rationality (moral reasoning about right and wrong actions). Phronesis is the virtue that should ensure ethical behaviour in actions, yet over time, social science research, in a quest to mimic the natural sciences, centred on episteme and techne. I constructed the lens by particularising the four value-rational questions of Flyvbjerg’s contemporary Phronesis to the performative perspective of the research. My interest in social reality, as well as socio-technical aspects, have led to design-ethnography (D-E) to emerge as the most suitable and most appropriate approach to the research. D-E asked the prescriptive ‘How’ and descriptive ‘What’ questions, whilst the Flyvbjergian Phronesis lens brought focus on the ‘Why’ question. D-E emphasised the betterment of the interaction and synergy between research conducted and practice. My status as an immersed researcher needed careful consideration, and D-E accepted that a certain level of immersion is necessary, D-E has short interventional fieldwork, and D-E has future-oriented engagement. The contemporary Phronesis used in the research is to enact D-E and not an all-encompassing guide for doing Phronesis research The key contributions to the research are predominantly methodological. The claims draw on evidence focused on the three themes technology, individuals and organisation, and the phenomena of interest which are to rebalance the social and the technological in CM practices. The first claim is that immersion in the context is possible and supported by the specific particularised approaches to the research. The second claim suggests a way to rebalance the socio-technical nature of Information Systems (IS). The third claim suggests that there is a viewpoint for power that is not focused on power’s oppressive nature which could see a diverging focus on power in IS research in future. In this viewpoint, the status quo of social reality is not questioned, nor are their emancipatory ambitions. The fourth and final claim suggests that Phronesis as a lens could enact D-E, which in turn is a method that assists in valuing the experience of the practitioner and the support of collaborative work. The research is recommended for IT/IS practitioners who prefer to value participants’ views in design. The approaches used could be of value for researchers who consider the context of their research to be of higher importance than the generalisation of outcomes. Researchers who find themselves in the position of being immersed in the context but question the correctness of active engagement in the field may discover some value from the research approaches and my experience. Also, researchers or practitioners who have an interest in the balance between social and the technological aspects of IS projects. Researchers or practitioners interested in Phronesis, and perhaps the viewpoint of a lens may also find value in this research.
- Full Text:
- Date Issued: 2020
- Authors: Jordaan, Leandra
- Date: 2020
- Subjects: Database management -- Social aspects , Information technology -- Social aspects , Management information systems -- Social aspects , Database management -- Philosophy , Information technology -- Philosophy , Management information systems -- Philosophy
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/164781 , vital:41164
- Description: As a practitioner, I had been part of two Content Management System (CMS) Projects in a particular setting that did not deliver on the expected outcomes. The expected outcomes of the projects included streamlined processes, better access to information, functionalities to drive engagement, reduced time searching for information, and improved reusability of content. As I began to reflect on the projects, a certain discomfort developed when the social aspect was ignored in favour of the technological. I sought a better understanding, but I was unaware of the fact at first. The techno-centricity as a concept found in literature and my experience as content management (CM) practitioner – together informed my interest in rebalancing the social and the technological. Thus, I focused on conduct in performing of tasks and emphasised attention on the practices of experts who gave insight into context of CM and use. The research participants are communication practitioners who have the responsibility to communicate internally and externally on behalf of a publicly-funded university in South Africa. Guided by the abductive argument and literature, the key themes for the research focused on technology, individuals and the organisation. The focus on technology (CMS as a subfield of Information Systems) began with my involvement in two CMS Projects. What came to the fore was that the practitioner perspective, and thus their experiential knowledge are neglected in research and that it may be an over-emphasis on techno-centrism in CMS research. I sought to better balance the social and technological aspects. The second focus on individuals (communication practitioners) was to value the stakeholder who was considered representative of the worldviews of the community. I sought to support corporate communication practices in the task of relationship building with stakeholders. The findings showed that the culture of informatio sharing was low at the University. The third focus on the organisation (the University) was to prioritise the success of the communication undertaken by the University. I interrogated the role of power. I demonstrated how the role of power could be seen as productive and positive in the context of HE, the social reality of CUT, and this IS research itself. I positioned the research as interpretivistic. I used hermeneutics as a mode of analysis because as researcher-practitioner, I am part of the social reality of the research. A safeguard against my subjectivity was the use of Phronesis as an orientation to knowledge. An organisation with a shared understanding of ethics and values will balance instrumental rationality (scientific and technical reasoning) with value-rationality (moral reasoning about right and wrong actions). Phronesis is the virtue that should ensure ethical behaviour in actions, yet over time, social science research, in a quest to mimic the natural sciences, centred on episteme and techne. I constructed the lens by particularising the four value-rational questions of Flyvbjerg’s contemporary Phronesis to the performative perspective of the research. My interest in social reality, as well as socio-technical aspects, have led to design-ethnography (D-E) to emerge as the most suitable and most appropriate approach to the research. D-E asked the prescriptive ‘How’ and descriptive ‘What’ questions, whilst the Flyvbjergian Phronesis lens brought focus on the ‘Why’ question. D-E emphasised the betterment of the interaction and synergy between research conducted and practice. My status as an immersed researcher needed careful consideration, and D-E accepted that a certain level of immersion is necessary, D-E has short interventional fieldwork, and D-E has future-oriented engagement. The contemporary Phronesis used in the research is to enact D-E and not an all-encompassing guide for doing Phronesis research The key contributions to the research are predominantly methodological. The claims draw on evidence focused on the three themes technology, individuals and organisation, and the phenomena of interest which are to rebalance the social and the technological in CM practices. The first claim is that immersion in the context is possible and supported by the specific particularised approaches to the research. The second claim suggests a way to rebalance the socio-technical nature of Information Systems (IS). The third claim suggests that there is a viewpoint for power that is not focused on power’s oppressive nature which could see a diverging focus on power in IS research in future. In this viewpoint, the status quo of social reality is not questioned, nor are their emancipatory ambitions. The fourth and final claim suggests that Phronesis as a lens could enact D-E, which in turn is a method that assists in valuing the experience of the practitioner and the support of collaborative work. The research is recommended for IT/IS practitioners who prefer to value participants’ views in design. The approaches used could be of value for researchers who consider the context of their research to be of higher importance than the generalisation of outcomes. Researchers who find themselves in the position of being immersed in the context but question the correctness of active engagement in the field may discover some value from the research approaches and my experience. Also, researchers or practitioners who have an interest in the balance between social and the technological aspects of IS projects. Researchers or practitioners interested in Phronesis, and perhaps the viewpoint of a lens may also find value in this research.
- Full Text:
- Date Issued: 2020
Design of Immunobiosensors for Detection of Tumor-Associated Anti-P53 Autoantibodies: Method Development
- Authors: Adeniyi, Omotayo Kayode
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/162988 , vital:41002 , 10.21504/10962/162988
- Description: Introduction -- Experimental -- Label-Free Impedimetric Sensing of Anti-P53ab... -- Fluorescent detection of Anti-P53ab -- Peroxidase-like activity of Fe3O4@SiNP-APTES-Au@Pd... -- Colorimetric detection of Anti-P53ab , Thesis (PhD)--Rhodes University, Science Faculty, Department of Chemistry, 2020. , Detection and profiling of circulating tumor-associated autoantibodies (TAAbs) are useful for screening and early-stage diagnosis of asymptomatic lung cancer. Immunobiosensor technologies aimed to accomplish the highly sensitive, rapid and low-cost detection of TAAbs can improve the early-stage detection of lung cancer. Immunobiosensors for the detection of anti-P53-tumour associated autoantibodies have been developed in this work. The design of sensing interfaces with immobilized P53 protein (P53ag) as a sensing element layer on a solid interface was investigated. Several methods of detecting anti-P53-antibodies (anti-P53ab) were investigated. These methods are label-free detection using electrochemical impedance spectroscopy (EIS) and two label techniques. The label-free electrochemical techniques utilize gold electrode pre-modified with a conducting layer of electrochemically grafted phenylethylamine for covalent immobilization of P53ag. The limit of anti-P53ab detection with the label-free EIS was 103.0 pg.ml-1. The labeled technique developed utilizes fluorescent, and peroxidase-like nanomaterial labeled antibody as a detection probe. For the fluorescence detection, fluorescent silica nanoparticles were synthesized by overloading FITC into the silica matrix and conjugated to detection antibody (anti-IgG). The detection of the anti-P53ab was based on the dissolution of the silica nanoparticles to release the loaded dye as a signal amplification strategy. The fluorescence detection was carried out on a microplate, and magnetic bead modified P53-antigen platforms and limit of detection (LoD) were 42.0 fg.ml-1 and 3.3 fg.ml-1 for anti-P53ab; respectively. Fe3O4@SiNP-APTES-Au@Pd hybrid nanoparticles were synthesized, and their peroxidase-like activity and colorimetric detection were evaluated. The Fe3O4@SiNP-APTES-Au@Pd exhibited comparable activity to HRP. The Fe3O4@SiNP-APTES-Au@Pd was conjugated to protein-G-anti-IgG for the detection of anti-P53ab on a microplate and cellulose paper platforms. The LoD was 20.0 fg.ml-1 and 63.0 fg.ml-1 for the microplate and cellulose paper platform; respectively. The potential application of the designed immunobiosensor was evaluated in simulated serum samples. The developed sensors showed higher detection sensitivity, stability and had a lower detection limit for anti-P53ab when compared with the ELISA based detection. The results have provided alternative and effective quantification approaches to ELISA and a promising future for multiplexed detection of tumor-associated autoantibodies. The developed methodologies in this thesis could be applied for the detection of other autoantibodies in other cancer types and auto-immune diseases.
- Full Text:
- Date Issued: 2020
- Authors: Adeniyi, Omotayo Kayode
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/162988 , vital:41002 , 10.21504/10962/162988
- Description: Introduction -- Experimental -- Label-Free Impedimetric Sensing of Anti-P53ab... -- Fluorescent detection of Anti-P53ab -- Peroxidase-like activity of Fe3O4@SiNP-APTES-Au@Pd... -- Colorimetric detection of Anti-P53ab , Thesis (PhD)--Rhodes University, Science Faculty, Department of Chemistry, 2020. , Detection and profiling of circulating tumor-associated autoantibodies (TAAbs) are useful for screening and early-stage diagnosis of asymptomatic lung cancer. Immunobiosensor technologies aimed to accomplish the highly sensitive, rapid and low-cost detection of TAAbs can improve the early-stage detection of lung cancer. Immunobiosensors for the detection of anti-P53-tumour associated autoantibodies have been developed in this work. The design of sensing interfaces with immobilized P53 protein (P53ag) as a sensing element layer on a solid interface was investigated. Several methods of detecting anti-P53-antibodies (anti-P53ab) were investigated. These methods are label-free detection using electrochemical impedance spectroscopy (EIS) and two label techniques. The label-free electrochemical techniques utilize gold electrode pre-modified with a conducting layer of electrochemically grafted phenylethylamine for covalent immobilization of P53ag. The limit of anti-P53ab detection with the label-free EIS was 103.0 pg.ml-1. The labeled technique developed utilizes fluorescent, and peroxidase-like nanomaterial labeled antibody as a detection probe. For the fluorescence detection, fluorescent silica nanoparticles were synthesized by overloading FITC into the silica matrix and conjugated to detection antibody (anti-IgG). The detection of the anti-P53ab was based on the dissolution of the silica nanoparticles to release the loaded dye as a signal amplification strategy. The fluorescence detection was carried out on a microplate, and magnetic bead modified P53-antigen platforms and limit of detection (LoD) were 42.0 fg.ml-1 and 3.3 fg.ml-1 for anti-P53ab; respectively. Fe3O4@SiNP-APTES-Au@Pd hybrid nanoparticles were synthesized, and their peroxidase-like activity and colorimetric detection were evaluated. The Fe3O4@SiNP-APTES-Au@Pd exhibited comparable activity to HRP. The Fe3O4@SiNP-APTES-Au@Pd was conjugated to protein-G-anti-IgG for the detection of anti-P53ab on a microplate and cellulose paper platforms. The LoD was 20.0 fg.ml-1 and 63.0 fg.ml-1 for the microplate and cellulose paper platform; respectively. The potential application of the designed immunobiosensor was evaluated in simulated serum samples. The developed sensors showed higher detection sensitivity, stability and had a lower detection limit for anti-P53ab when compared with the ELISA based detection. The results have provided alternative and effective quantification approaches to ELISA and a promising future for multiplexed detection of tumor-associated autoantibodies. The developed methodologies in this thesis could be applied for the detection of other autoantibodies in other cancer types and auto-immune diseases.
- Full Text:
- Date Issued: 2020
Design of immunosensor for the detection of C-reactive protein using oriented antibody immobilization
- Authors: Adesina, Abiola Olanike
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/163080 , vital:41010 , https://dx.doi.org/10.21504/10962/163080
- Description: Thesis (PhD)--Rhodes University, Science Faculty, Department of Chemistry, 2020.
- Full Text:
- Date Issued: 2020
- Authors: Adesina, Abiola Olanike
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/163080 , vital:41010 , https://dx.doi.org/10.21504/10962/163080
- Description: Thesis (PhD)--Rhodes University, Science Faculty, Department of Chemistry, 2020.
- Full Text:
- Date Issued: 2020
Design, formulation and evalauation of liposomes co-loaded with human serum Albumin and Rifampicin
- Authors: Bapolisi, Alain Murhimalika
- Date: 2020
- Subjects: Liposomes , Serum albumin , Rifampin , Mycobacterium tuberculosis
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/161780 , vital:40670
- Description: Tuberculosis (TB) is a devastating infectious disease caused by Mycobacterium tuberculosis and is the leading cause of death from a single infectious agent. The high morbidity and mortality rates of TB are partly due to factors such as the lengthy regimen (of 6–24 months), the development of drug resistance, and the pathogen location within the macrophages. These, with poor physiochemical properties of existing drugs hamper the effectiveness of the treatment despite the existence of potent antibiotics such as Rifampicin (Rif). Hydrophobicity plagues many drugs, including Rif, which are then particularly affected due to inherently poor intracellular availability. Novel drug delivery approaches are therefore needed in order to optimize the cytotoxic potential of said antitubercular drugs. To improve the bioavailability of hydrophobic drugs, numerous delivery strategies have been developed. Amongst these, the coordination of cytotoxic drugs to therapeutic proteins have shown some success for improved efficacy in the management of illnesses including infectious diseases. Of therapeutic proteins, Human Serum Albumin (HSA) is an attractive drug carrier with interestingbenefits such as low immunogenicity, antioxidant properties and improving cellular uptake ofdrugs through HSA-specific binding sites which are expressed on most cells including macrophages, where M. tuberculosis often resides. Hence, combination of Rif to HSA (Rif-HSA)seems a promising approach for improved intracellular delivery of Rif. However, the in vivo stability of colloidal protein-based therapeutics is mostly challenging and an effective vehicle is needed to control the biological fate of such conjugates.Liposomes seem to be appropriate carriers for the Rif-HSA complex due to their reputable applicability for encapsulating diverse materials (i.e., hydrophobic and hydrophilic compounds or small and complex molecules) and preventing chemical and biological degradation of the cargo. Therefore, the main objective of this study was to simultaneously encapsulate Rif and HSA in liposomes, which, to the best of our knowledge, has not been done before. The dual liposomes (Rif-HSA-lip) were made by a modified “Reverse Phase Evaporation” method (REV), following a Design of Experiments (DOE) approach to determine which factors impact the formulation. In addition, liposomes were made from crude soybean lecithin (CSL), rather than expensive and highly purified lipids. The liposomes were fully characterised, and the encapsulation efficiency (î) was monitored using high-performance liquid chromatography (HPLC). The results were correlated with factors such as organic and aqueous phase composition, as well as the in vitro release profile of Rif. Transmission electron microscopy (TEM) results confirmed the formation of spherical dual liposomes nanoparticles of roughly 200 nm. Dynamic light scattering (DLS) and Zeta potential measurements showed a negative charge (<–45 mV) and with satisfactory polydispersity (PDI<0.5). HSA dramatically improved the aqueous solubility of Rif (from1.9 mg/ml in water to around 4.3 mg/ml in HSA 10% solution) mainly due to Rif-HSA hydrophobic interactions. This resulted in a good î of almost 60% for Rif, despite the presence of bulky HSA in the lipid bilayer. These details were confirmed using proton nuclear magnetic resonance (1H NMR) and Fourier-transform infrared spectroscopy (FTIR). Furthermore, energy dispersive X-ray (EDX) and DLS data suggested the presence of HSA poking out on the surface of liposomes, which is encouraging for potential targeted delivery in the future. The in vitro release studies also depicted a substantial improvement in the diffusion of Rif in dual liposomes versus free Rif, from 65% after 12 hours for free Rif to 95% after only 5 hours for Rif- HSA-lip. Finally, stability studies conducted over 30 days at room temperature, showed that the freeze-dried formulations of Rif-HSA-lip exhibited good shelf stability over liposomes with no HSA. This study represents an illustrative example of co-loading of antibiotics and proteins into liposomes, which could encourage further development of novel nanoparticulate tools for the effective management of both drug-susceptible and -resistant infectious diseases such as TB.
- Full Text:
- Date Issued: 2020
- Authors: Bapolisi, Alain Murhimalika
- Date: 2020
- Subjects: Liposomes , Serum albumin , Rifampin , Mycobacterium tuberculosis
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/161780 , vital:40670
- Description: Tuberculosis (TB) is a devastating infectious disease caused by Mycobacterium tuberculosis and is the leading cause of death from a single infectious agent. The high morbidity and mortality rates of TB are partly due to factors such as the lengthy regimen (of 6–24 months), the development of drug resistance, and the pathogen location within the macrophages. These, with poor physiochemical properties of existing drugs hamper the effectiveness of the treatment despite the existence of potent antibiotics such as Rifampicin (Rif). Hydrophobicity plagues many drugs, including Rif, which are then particularly affected due to inherently poor intracellular availability. Novel drug delivery approaches are therefore needed in order to optimize the cytotoxic potential of said antitubercular drugs. To improve the bioavailability of hydrophobic drugs, numerous delivery strategies have been developed. Amongst these, the coordination of cytotoxic drugs to therapeutic proteins have shown some success for improved efficacy in the management of illnesses including infectious diseases. Of therapeutic proteins, Human Serum Albumin (HSA) is an attractive drug carrier with interestingbenefits such as low immunogenicity, antioxidant properties and improving cellular uptake ofdrugs through HSA-specific binding sites which are expressed on most cells including macrophages, where M. tuberculosis often resides. Hence, combination of Rif to HSA (Rif-HSA)seems a promising approach for improved intracellular delivery of Rif. However, the in vivo stability of colloidal protein-based therapeutics is mostly challenging and an effective vehicle is needed to control the biological fate of such conjugates.Liposomes seem to be appropriate carriers for the Rif-HSA complex due to their reputable applicability for encapsulating diverse materials (i.e., hydrophobic and hydrophilic compounds or small and complex molecules) and preventing chemical and biological degradation of the cargo. Therefore, the main objective of this study was to simultaneously encapsulate Rif and HSA in liposomes, which, to the best of our knowledge, has not been done before. The dual liposomes (Rif-HSA-lip) were made by a modified “Reverse Phase Evaporation” method (REV), following a Design of Experiments (DOE) approach to determine which factors impact the formulation. In addition, liposomes were made from crude soybean lecithin (CSL), rather than expensive and highly purified lipids. The liposomes were fully characterised, and the encapsulation efficiency (î) was monitored using high-performance liquid chromatography (HPLC). The results were correlated with factors such as organic and aqueous phase composition, as well as the in vitro release profile of Rif. Transmission electron microscopy (TEM) results confirmed the formation of spherical dual liposomes nanoparticles of roughly 200 nm. Dynamic light scattering (DLS) and Zeta potential measurements showed a negative charge (<–45 mV) and with satisfactory polydispersity (PDI<0.5). HSA dramatically improved the aqueous solubility of Rif (from1.9 mg/ml in water to around 4.3 mg/ml in HSA 10% solution) mainly due to Rif-HSA hydrophobic interactions. This resulted in a good î of almost 60% for Rif, despite the presence of bulky HSA in the lipid bilayer. These details were confirmed using proton nuclear magnetic resonance (1H NMR) and Fourier-transform infrared spectroscopy (FTIR). Furthermore, energy dispersive X-ray (EDX) and DLS data suggested the presence of HSA poking out on the surface of liposomes, which is encouraging for potential targeted delivery in the future. The in vitro release studies also depicted a substantial improvement in the diffusion of Rif in dual liposomes versus free Rif, from 65% after 12 hours for free Rif to 95% after only 5 hours for Rif- HSA-lip. Finally, stability studies conducted over 30 days at room temperature, showed that the freeze-dried formulations of Rif-HSA-lip exhibited good shelf stability over liposomes with no HSA. This study represents an illustrative example of co-loading of antibiotics and proteins into liposomes, which could encourage further development of novel nanoparticulate tools for the effective management of both drug-susceptible and -resistant infectious diseases such as TB.
- Full Text:
- Date Issued: 2020
Design, formulation and evaluation of liposomes co-loaded with human serum albumin and rifampicin
- Authors: Bapolisi, Alain Murhimalika
- Date: 2020
- Subjects: Liposomes , Rifampin , Antitubercular agents , Serum albumin , Albumins , Tuberculosis -- Treatment
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/163179 , vital:41016
- Description: Tuberculosis (TB) is a devastating infectious disease caused by Mycobacterium tuberculosis and is the leading cause of death from a single infectious agent. The high morbidity and mortality rates of TB are partly due to factors such as the lengthy regimen (of 6–24 months), the development of drug resistance, and the pathogen location within the macrophages. These, with poor physiochemical properties of existing drugs hamper the effectiveness of the treatment despite the existence of potent antibiotics such as Rifampicin (Rif). Hydrophobicity plagues many drugs, including Rif, which are then particularly affected due to inherently poor intracellular availability. Novel drug delivery approaches are therefore needed in order to optimize the cytotoxic potential of said antitubercular drugs. To improve the bioavailability of hydrophobic drugs, numerous delivery strategies have been developed. Amongst these, the coordination of cytotoxic drugs to therapeutic proteins have shown some success for improved efficacy in the management of illnesses including infectious diseases. Of therapeutic proteins, Human Serum Albumin (HSA) is an attractive drug carrier with interesting benefits such as low immunogenicity, antioxidant properties and improving cellular uptake of drugs through HSA-specific binding sites which are expressed on most cells including macrophages, where M. tuberculosis often resides. Hence, combination of Rif to HSA (Rif-HSA) seems a promising approach for improved intracellular delivery of Rif. However, the in vivo stability of colloidal protein-based therapeutics is mostly challenging and an effective vehicle is needed to control the biological fate of such conjugates. Liposomes seem to be appropriate carriers for the Rif-HSA complex due to their reputable applicability for encapsulating diverse materials (i.e., hydrophobic and hydrophilic compounds or small and complex molecules) and preventing chemical and biological degradation of the cargo. Therefore, the main objective of this study was to simultaneously encapsulate Rif and HSA in liposomes, which, to the best of our knowledge, has not been done before. The dual liposomes (Rif-HSA-lip) were made by a modified “Reverse Phase Evaporation” method (REV), following a Design of Experiments (DOE) approach to determine which factors impact the formulation. In addition, liposomes were made from crude soybean lecithin (CSL), rather than expensive and highly purified lipids. iv The liposomes were fully characterised, and the encapsulation efficiency (î) was monitored using high-performance liquid chromatography (HPLC). The results were correlated with factors such as organic and aqueous phase composition, as well as the in vitro release profile of Rif. Transmission electron microscopy (TEM) results confirmed the formation of spherical dual liposomes nanoparticles of roughly 200 nm. Dynamic light scattering (DLS) and Zeta potential measurements showed a negative charge (<–45 mV) and with satisfactory polydispersity (PDI<0.5). HSA dramatically improved the aqueous solubility of Rif (from1.9 mg/ml in water to around 4.3 mg/ml in HSA 10% solution) mainly due to Rif-HSA hydrophobic interactions. This resulted in a good î of almost 60% for Rif, despite the presence of bulky HSA in the lipid bilayer. These details were confirmed using proton nuclear magnetic resonance (1H NMR) and Fourier-transform infrared spectroscopy (FTIR). Furthermore, energy dispersive X-ray (EDX) and DLS data suggested the presence of HSA poking out on the surface of liposomes, which is encouraging for potential targeted delivery in the future. The in vitro release studies also depicted a substantial improvement in the diffusion of Rif in dual liposomes versus free Rif, from 65% after 12 hours for free Rif to 95% after only 5 hours for Rif- HSA-lip. Finally, stability studies conducted over 30 days at room temperature, showed that the freeze-dried formulations of Rif-HSA-lip exhibited good shelf stability over liposomes with no HSA. This study represents an illustrative example of co-loading of antibiotics and proteins into liposomes, which could encourage further development of novel nanoparticulate tools for the effective management of both drug-susceptible and -resistant infectious diseases such as TB.
- Full Text:
- Date Issued: 2020
- Authors: Bapolisi, Alain Murhimalika
- Date: 2020
- Subjects: Liposomes , Rifampin , Antitubercular agents , Serum albumin , Albumins , Tuberculosis -- Treatment
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/163179 , vital:41016
- Description: Tuberculosis (TB) is a devastating infectious disease caused by Mycobacterium tuberculosis and is the leading cause of death from a single infectious agent. The high morbidity and mortality rates of TB are partly due to factors such as the lengthy regimen (of 6–24 months), the development of drug resistance, and the pathogen location within the macrophages. These, with poor physiochemical properties of existing drugs hamper the effectiveness of the treatment despite the existence of potent antibiotics such as Rifampicin (Rif). Hydrophobicity plagues many drugs, including Rif, which are then particularly affected due to inherently poor intracellular availability. Novel drug delivery approaches are therefore needed in order to optimize the cytotoxic potential of said antitubercular drugs. To improve the bioavailability of hydrophobic drugs, numerous delivery strategies have been developed. Amongst these, the coordination of cytotoxic drugs to therapeutic proteins have shown some success for improved efficacy in the management of illnesses including infectious diseases. Of therapeutic proteins, Human Serum Albumin (HSA) is an attractive drug carrier with interesting benefits such as low immunogenicity, antioxidant properties and improving cellular uptake of drugs through HSA-specific binding sites which are expressed on most cells including macrophages, where M. tuberculosis often resides. Hence, combination of Rif to HSA (Rif-HSA) seems a promising approach for improved intracellular delivery of Rif. However, the in vivo stability of colloidal protein-based therapeutics is mostly challenging and an effective vehicle is needed to control the biological fate of such conjugates. Liposomes seem to be appropriate carriers for the Rif-HSA complex due to their reputable applicability for encapsulating diverse materials (i.e., hydrophobic and hydrophilic compounds or small and complex molecules) and preventing chemical and biological degradation of the cargo. Therefore, the main objective of this study was to simultaneously encapsulate Rif and HSA in liposomes, which, to the best of our knowledge, has not been done before. The dual liposomes (Rif-HSA-lip) were made by a modified “Reverse Phase Evaporation” method (REV), following a Design of Experiments (DOE) approach to determine which factors impact the formulation. In addition, liposomes were made from crude soybean lecithin (CSL), rather than expensive and highly purified lipids. iv The liposomes were fully characterised, and the encapsulation efficiency (î) was monitored using high-performance liquid chromatography (HPLC). The results were correlated with factors such as organic and aqueous phase composition, as well as the in vitro release profile of Rif. Transmission electron microscopy (TEM) results confirmed the formation of spherical dual liposomes nanoparticles of roughly 200 nm. Dynamic light scattering (DLS) and Zeta potential measurements showed a negative charge (<–45 mV) and with satisfactory polydispersity (PDI<0.5). HSA dramatically improved the aqueous solubility of Rif (from1.9 mg/ml in water to around 4.3 mg/ml in HSA 10% solution) mainly due to Rif-HSA hydrophobic interactions. This resulted in a good î of almost 60% for Rif, despite the presence of bulky HSA in the lipid bilayer. These details were confirmed using proton nuclear magnetic resonance (1H NMR) and Fourier-transform infrared spectroscopy (FTIR). Furthermore, energy dispersive X-ray (EDX) and DLS data suggested the presence of HSA poking out on the surface of liposomes, which is encouraging for potential targeted delivery in the future. The in vitro release studies also depicted a substantial improvement in the diffusion of Rif in dual liposomes versus free Rif, from 65% after 12 hours for free Rif to 95% after only 5 hours for Rif- HSA-lip. Finally, stability studies conducted over 30 days at room temperature, showed that the freeze-dried formulations of Rif-HSA-lip exhibited good shelf stability over liposomes with no HSA. This study represents an illustrative example of co-loading of antibiotics and proteins into liposomes, which could encourage further development of novel nanoparticulate tools for the effective management of both drug-susceptible and -resistant infectious diseases such as TB.
- Full Text:
- Date Issued: 2020
Design, Optimization, Manufacture and Characterization of Efavirenz-Loaded Flaxseed Oil Nanoemulsions
- Mazonde, Priveledge, Khamanga, Sandile M, Walker, Roderick B
- Authors: Mazonde, Priveledge , Khamanga, Sandile M , Walker, Roderick B
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183183 , vital:43919 , xlink:href="https://doi.org/10.3390/pharmaceutics12090797"
- Description: The formation, manufacture and characterization of low energy water-in-oil (w/o) nanoemulsions prepared using cold pressed flaxseed oil containing efavirenz was investigated. Pseudo-ternary phase diagrams were constructed to identify the nanoemulsion region(s). Other potential lipid-based drug delivery phases containing flaxseed oil with 1:1 m/m surfactant mixture of Tween® 80, Span® 20 and different amounts of ethanol were tested to characterize the impact of surfactant mixture on emulsion formation. Flaxseed oil was used as the oil phase as efavirenz exhibited high solubility in the vehicle when compared to other vegetable oils tested. Optimization of surfactant mixtures was undertaken using design of experiments, specifically a D-optimal design with the flaxseed oil content set at 10% m/m. Two solutions from the desired optimization function were produced based on desirability and five nanoemulsion formulations were produced and characterized in terms of in vitro release of efavirenz, physical and chemical stability. Metastable nanoemulsions containing 10% m/m flaxseed oil were successfully manufactured and significant isotropic gel (semisolid) and o/w emulsions were observed during phase behavior studies. Droplet sizes ranged between 156 and 225 nm, zeta potential between −24 and −41 mV and all formulations were found to be monodisperse with polydispersity indices ≤ 0.487.
- Full Text:
- Date Issued: 2020
- Authors: Mazonde, Priveledge , Khamanga, Sandile M , Walker, Roderick B
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183183 , vital:43919 , xlink:href="https://doi.org/10.3390/pharmaceutics12090797"
- Description: The formation, manufacture and characterization of low energy water-in-oil (w/o) nanoemulsions prepared using cold pressed flaxseed oil containing efavirenz was investigated. Pseudo-ternary phase diagrams were constructed to identify the nanoemulsion region(s). Other potential lipid-based drug delivery phases containing flaxseed oil with 1:1 m/m surfactant mixture of Tween® 80, Span® 20 and different amounts of ethanol were tested to characterize the impact of surfactant mixture on emulsion formation. Flaxseed oil was used as the oil phase as efavirenz exhibited high solubility in the vehicle when compared to other vegetable oils tested. Optimization of surfactant mixtures was undertaken using design of experiments, specifically a D-optimal design with the flaxseed oil content set at 10% m/m. Two solutions from the desired optimization function were produced based on desirability and five nanoemulsion formulations were produced and characterized in terms of in vitro release of efavirenz, physical and chemical stability. Metastable nanoemulsions containing 10% m/m flaxseed oil were successfully manufactured and significant isotropic gel (semisolid) and o/w emulsions were observed during phase behavior studies. Droplet sizes ranged between 156 and 225 nm, zeta potential between −24 and −41 mV and all formulations were found to be monodisperse with polydispersity indices ≤ 0.487.
- Full Text:
- Date Issued: 2020