Fluorescence behaviour of supramolecular hybrids containing graphene quantum dots and pyrene-derivatized phthalocyanines and porphyrins
- Achadu, Ojodomo John, Managa, Muthumuni, Nyokong, Tebello
- Authors: Achadu, Ojodomo John , Managa, Muthumuni , Nyokong, Tebello
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188953 , vital:44801 , xlink:href="https://doi.org/10.1016/j.jphotochem.2016.10.029"
- Description: Novel pyrene-derivatized zinc and cobalt phthalocyanines (Pcs) and porphyrins (Ps) were immobilized on graphene quantum dots (GQDs) to form GQDs-Pcs and GQDs-Ps supramolecular hybrids via the π–π stacking interaction method. Spectroscopic evidence shows that the resultant hybrids were stable owing to the strong π–π stacking interaction between the GQDs and the respective Pcs and Ps, thus leading to the fabrication of interesting and functional supramolecular hybrids by taking advantage of the delocalized π electron systems of GQDs and the macrocycles. The conjugates showed increased fluorescence quantum yields for the Pcs/Ps, but decreased values for the GQDs in the conjugates. These novel hybrid materials could potentially be deployed for studies in both fundamental and applied perspectives due to the synergistic contributions resulting from the combination of their excellent electronic and optical properties.
- Full Text:
- Date Issued: 2017
- Authors: Achadu, Ojodomo John , Managa, Muthumuni , Nyokong, Tebello
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188953 , vital:44801 , xlink:href="https://doi.org/10.1016/j.jphotochem.2016.10.029"
- Description: Novel pyrene-derivatized zinc and cobalt phthalocyanines (Pcs) and porphyrins (Ps) were immobilized on graphene quantum dots (GQDs) to form GQDs-Pcs and GQDs-Ps supramolecular hybrids via the π–π stacking interaction method. Spectroscopic evidence shows that the resultant hybrids were stable owing to the strong π–π stacking interaction between the GQDs and the respective Pcs and Ps, thus leading to the fabrication of interesting and functional supramolecular hybrids by taking advantage of the delocalized π electron systems of GQDs and the macrocycles. The conjugates showed increased fluorescence quantum yields for the Pcs/Ps, but decreased values for the GQDs in the conjugates. These novel hybrid materials could potentially be deployed for studies in both fundamental and applied perspectives due to the synergistic contributions resulting from the combination of their excellent electronic and optical properties.
- Full Text:
- Date Issued: 2017
Perceptions of parents on their involvement in the implementation of the prevention and management of learner pregnancy : a case study of three secondary schools in Amathole West District
- Authors: Mxothwa, Smileth Ncumisa
- Date: 2020-06
- Subjects: Pregnant teenagers , Sex instruction for teenagers
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/19991 , vital:44923
- Description: There is quite a number of researches dealing with perceptions of parents on the prevention and management of learner pregnancy. However, less has been said about how these perceptions of parents on the prevention and management are being implemented to fulfil their purpose. Discovering how these perceptions are being implemented is necessary, bearing in mind that a large number of Schools are having high learner pregnancy and are lacking parental involvement in South Africa, particularly in terms of prevention and management. This is a qualitative study that seeks to explore the perceptions of parents on their implementation of the prevention and management of the learner pregnancy policy in the three secondary school in the Amathole West Education District. The interpretivism paradigm was used by the researcher for this study. A case study design was further used to detect the participants’ lived experiences, thoughts and outlooks about the implementation of the prevention and management of learner pregnancy policy in the secondary school. The data was collected through the use of interviews and focus group. The participants were purposefully selected in the sampling of this study. The participants included School Governing Body Chairpersons. In total, the study consisted of 18 participants. The data were analysed by reducing data into themes through the process of coding. It was further shortened and organised based on evolving themes, overall ideas, and related features. The study discovered that parents are not made aware of their importance by being involved at school level and also are not involved in the implementation of the prevention and management of learner pregnancy policy in the secondary schools in the Amathole West Education District. This research revealed that there need for parental involvement be practised by all schools in the implementation of the prevention and management of learner pregnancy policy as this would help in reducing learner pregnancy in secondary schools of Amathole West Education District. Findings also showed that though parents used different strategies to prevent learner pregnancy, these were not in line with pregnancy policy. The study also discovered that there is a lack of support and monitoring from the district officials to schools. , Thesis (MEd) -- Faculty of Education, 2020
- Full Text:
- Date Issued: 2020-06
- Authors: Mxothwa, Smileth Ncumisa
- Date: 2020-06
- Subjects: Pregnant teenagers , Sex instruction for teenagers
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/19991 , vital:44923
- Description: There is quite a number of researches dealing with perceptions of parents on the prevention and management of learner pregnancy. However, less has been said about how these perceptions of parents on the prevention and management are being implemented to fulfil their purpose. Discovering how these perceptions are being implemented is necessary, bearing in mind that a large number of Schools are having high learner pregnancy and are lacking parental involvement in South Africa, particularly in terms of prevention and management. This is a qualitative study that seeks to explore the perceptions of parents on their implementation of the prevention and management of the learner pregnancy policy in the three secondary school in the Amathole West Education District. The interpretivism paradigm was used by the researcher for this study. A case study design was further used to detect the participants’ lived experiences, thoughts and outlooks about the implementation of the prevention and management of learner pregnancy policy in the secondary school. The data was collected through the use of interviews and focus group. The participants were purposefully selected in the sampling of this study. The participants included School Governing Body Chairpersons. In total, the study consisted of 18 participants. The data were analysed by reducing data into themes through the process of coding. It was further shortened and organised based on evolving themes, overall ideas, and related features. The study discovered that parents are not made aware of their importance by being involved at school level and also are not involved in the implementation of the prevention and management of learner pregnancy policy in the secondary schools in the Amathole West Education District. This research revealed that there need for parental involvement be practised by all schools in the implementation of the prevention and management of learner pregnancy policy as this would help in reducing learner pregnancy in secondary schools of Amathole West Education District. Findings also showed that though parents used different strategies to prevent learner pregnancy, these were not in line with pregnancy policy. The study also discovered that there is a lack of support and monitoring from the district officials to schools. , Thesis (MEd) -- Faculty of Education, 2020
- Full Text:
- Date Issued: 2020-06
A reflective multiple case study approach to understanding partner relationships within the context of community engagement at Rhodes University
- Authors: Bobo, Azola Benita Dorothea
- Date: 2021-05-06
- Subjects: Community development South Africa Makhanda , Community and college South Africa Makhanda , Community psychology South Africa Makhanda , Decolonization South Africa , Social action South Africa Makhanda , Transformative learning South Africa Makhanda , Rhodes University , Rhodes University Community Engagement (RUCE)
- Language: English
- Type: Doctoral thesis , text
- Identifier: http://hdl.handle.net/10962/253854 , vital:52406 , DOI 10.21504/10962/253854
- Description: Using a social constructivist approach, within the social action model of community psychology, this research interrogates the features of successful community engagement partnerships that exist within the context of higher education. It draws on the co-management model that the Rhodes University Community Engagement (RUCE) division proposes, where partnerships are seen to be mutually beneficial. This research further interrogates whether the principles of community engagement that RUCE propose play out in reality, and whether systems of power are deconstructed, in working towards more equitable engagements. Drawing on the Early Childhood Development (ECD) Residence Programme for case studies, this research used a reflective multiple case study design in attempting to answer the research question. Four partner groups (i.e., 4 community partners and 4 community engagement representatives) were selected for this research. Each participant was interviewed twice (with a 6-month time gap) and also participated in two focus group discussions. Thematic analysis was used to analyse the findings. In taking a social justice approach, it can be argued that RUCE has made strides towards forming collaborative partnerships based on the ethics of ubuntu and aspects of transformative learning, which may lead to the decolonisation of higher education. However, critical engagement with the research findings suggests that in many cases the principles that RUCE propose are aspirational. More work needs to be done with both students and community partners to develop the kinds of partnerships that RUCE aspires to. This research provides valuable insight into how carefully managed community engagement partnerships in higher education have the potential to contribute to the transformation agenda of higher education institutions, while promoting equitable societies. , Thesis (PhD) -- Faculty of Humanities, Psychology, 2022
- Full Text:
- Date Issued: 2021-05-06
- Authors: Bobo, Azola Benita Dorothea
- Date: 2021-05-06
- Subjects: Community development South Africa Makhanda , Community and college South Africa Makhanda , Community psychology South Africa Makhanda , Decolonization South Africa , Social action South Africa Makhanda , Transformative learning South Africa Makhanda , Rhodes University , Rhodes University Community Engagement (RUCE)
- Language: English
- Type: Doctoral thesis , text
- Identifier: http://hdl.handle.net/10962/253854 , vital:52406 , DOI 10.21504/10962/253854
- Description: Using a social constructivist approach, within the social action model of community psychology, this research interrogates the features of successful community engagement partnerships that exist within the context of higher education. It draws on the co-management model that the Rhodes University Community Engagement (RUCE) division proposes, where partnerships are seen to be mutually beneficial. This research further interrogates whether the principles of community engagement that RUCE propose play out in reality, and whether systems of power are deconstructed, in working towards more equitable engagements. Drawing on the Early Childhood Development (ECD) Residence Programme for case studies, this research used a reflective multiple case study design in attempting to answer the research question. Four partner groups (i.e., 4 community partners and 4 community engagement representatives) were selected for this research. Each participant was interviewed twice (with a 6-month time gap) and also participated in two focus group discussions. Thematic analysis was used to analyse the findings. In taking a social justice approach, it can be argued that RUCE has made strides towards forming collaborative partnerships based on the ethics of ubuntu and aspects of transformative learning, which may lead to the decolonisation of higher education. However, critical engagement with the research findings suggests that in many cases the principles that RUCE propose are aspirational. More work needs to be done with both students and community partners to develop the kinds of partnerships that RUCE aspires to. This research provides valuable insight into how carefully managed community engagement partnerships in higher education have the potential to contribute to the transformation agenda of higher education institutions, while promoting equitable societies. , Thesis (PhD) -- Faculty of Humanities, Psychology, 2022
- Full Text:
- Date Issued: 2021-05-06
Electrocatalytic properties of vitamin B12 towards oxidation and reduction of nitric oxide
- Vilakazi, Sibulelo Lea, Nyokong, Tebello
- Authors: Vilakazi, Sibulelo Lea , Nyokong, Tebello
- Date: 2000
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293196 , vital:57064 , xlink:href="https://doi.org/10.1016/S0013-4686(00)00628-9"
- Description: This paper reports on the catalytic behaviour of cyanocobalamin (VB12) towards the reduction and oxidation of nitric oxide. When VB12 is adsorbed on glassy carbon electrodes, it catalyses the reduction of nitric oxide (NO) in pH 4 and 9 buffers. In the absence of NO, cyclic voltammetry shows that VB12 is reduced by a one-step two-electron reduction from CoIII to the CoI species. Addition of NO at pH 9 to solutions of VB12 resulted in the splitting of the cyclic voltammetry peaks as a result of a consecutive one-electron reduction of the central CoIII metal in VB12 to CoII and finally to CoI. The catalytic peak for oxidation of NO on a glassy carbon electrode modified with VB12 was observed at 1.21 V versus Ag∣AgCl, at pH 9. The products of the catalytic reduction of nitric oxide include ammonia and hydroxylamine.
- Full Text:
- Date Issued: 2000
- Authors: Vilakazi, Sibulelo Lea , Nyokong, Tebello
- Date: 2000
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293196 , vital:57064 , xlink:href="https://doi.org/10.1016/S0013-4686(00)00628-9"
- Description: This paper reports on the catalytic behaviour of cyanocobalamin (VB12) towards the reduction and oxidation of nitric oxide. When VB12 is adsorbed on glassy carbon electrodes, it catalyses the reduction of nitric oxide (NO) in pH 4 and 9 buffers. In the absence of NO, cyclic voltammetry shows that VB12 is reduced by a one-step two-electron reduction from CoIII to the CoI species. Addition of NO at pH 9 to solutions of VB12 resulted in the splitting of the cyclic voltammetry peaks as a result of a consecutive one-electron reduction of the central CoIII metal in VB12 to CoII and finally to CoI. The catalytic peak for oxidation of NO on a glassy carbon electrode modified with VB12 was observed at 1.21 V versus Ag∣AgCl, at pH 9. The products of the catalytic reduction of nitric oxide include ammonia and hydroxylamine.
- Full Text:
- Date Issued: 2000
Effects of pyrene on the photophysical and two-photon absorption-based nonlinear optical properties of indium (III) phthalocyanines
- Sanusi, Kayode, Nyokong, Tebello
- Authors: Sanusi, Kayode , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189957 , vital:44951 , xlink:href="https://doi.org/10.1080/00958972.2014.959509"
- Description: Photophysical and two-photon-dependent nonlinear absorption properties of two chloroindium(III) phthalocyanines bearing pyrene units have been investigated. The tetra- (3) and the tri- (4) pyrene-substituted phthalocyanines exhibit strong triplet absorption with high triplet yields ( ) of 0.79 and 0.83, respectively. The measured nonlinear optical data, such as the two photon absorption cross-sections, the third- and second-order nonlinearities were found to be comparable with those of literature, thus, making the compounds promising candidates for a broad range of nonlinear optical applications.
- Full Text:
- Date Issued: 2014
- Authors: Sanusi, Kayode , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189957 , vital:44951 , xlink:href="https://doi.org/10.1080/00958972.2014.959509"
- Description: Photophysical and two-photon-dependent nonlinear absorption properties of two chloroindium(III) phthalocyanines bearing pyrene units have been investigated. The tetra- (3) and the tri- (4) pyrene-substituted phthalocyanines exhibit strong triplet absorption with high triplet yields ( ) of 0.79 and 0.83, respectively. The measured nonlinear optical data, such as the two photon absorption cross-sections, the third- and second-order nonlinearities were found to be comparable with those of literature, thus, making the compounds promising candidates for a broad range of nonlinear optical applications.
- Full Text:
- Date Issued: 2014
Comparative phototransformation of environmental pollutants using metallophthalocyanines supported on electrospun polymer fibers
- Zugle, Ruphino, Nyokong, Tebello
- Authors: Zugle, Ruphino , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190509 , vital:45001 , xlink:href="https://doi.org/10.1002/app.38381"
- Description: The fluorescence and photoactivity of a series of Zn and Lu phthalocyanine complexes incorporated in various polymer fibers were investigated for the phototransformation of 4-chlorophenol, 4-nitrophenol, and methyl orange. The phthalocyanine complexes functionalized on polystyrene and polysulfone polymer fibers could be applied in the degradation of 4-chlorophenol, 4-nitrophenol, and methyl orange with 4-chlorophenol being much more susceptible to degradation while methyl orange was the least. Also polymer fibers of polystyrene were found to be reusable.
- Full Text:
- Date Issued: 2013
- Authors: Zugle, Ruphino , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190509 , vital:45001 , xlink:href="https://doi.org/10.1002/app.38381"
- Description: The fluorescence and photoactivity of a series of Zn and Lu phthalocyanine complexes incorporated in various polymer fibers were investigated for the phototransformation of 4-chlorophenol, 4-nitrophenol, and methyl orange. The phthalocyanine complexes functionalized on polystyrene and polysulfone polymer fibers could be applied in the degradation of 4-chlorophenol, 4-nitrophenol, and methyl orange with 4-chlorophenol being much more susceptible to degradation while methyl orange was the least. Also polymer fibers of polystyrene were found to be reusable.
- Full Text:
- Date Issued: 2013
Malnutrition in children under the age of 5 years in a primary health care setting
- Kaswa, Ramprakash, Govender, Indiran, Rangiah, Selvandran, Nzaumvila, Doudou
- Authors: Kaswa, Ramprakash , Govender, Indiran , Rangiah, Selvandran , Nzaumvila, Doudou
- Date: 2021
- Subjects: Obesity Malnutrition Dietary supplements Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/7260 , vital:53106 , xlink:href="https://doi.org/10.4102/safp.v63i1.5337"
- Description: In this study, we outlined the types of malnutrition amongst children, the causes of malnutrition intervention at the primary health care level and some recommendations to alleviate childhood malnutrition in South Africa. Keywords: obesity; severe acute malnutrition; individual factors; community level factors; dietary intervention.
- Full Text:
- Date Issued: 2021
- Authors: Kaswa, Ramprakash , Govender, Indiran , Rangiah, Selvandran , Nzaumvila, Doudou
- Date: 2021
- Subjects: Obesity Malnutrition Dietary supplements Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/7260 , vital:53106 , xlink:href="https://doi.org/10.4102/safp.v63i1.5337"
- Description: In this study, we outlined the types of malnutrition amongst children, the causes of malnutrition intervention at the primary health care level and some recommendations to alleviate childhood malnutrition in South Africa. Keywords: obesity; severe acute malnutrition; individual factors; community level factors; dietary intervention.
- Full Text:
- Date Issued: 2021
The implementation of a mobile application to decrease occupational sitting through goal setting and social comparison
- Authors: Tsaoane, Moipone Lipalesa
- Date: 2022-10-14
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/365544 , vital:65758
- Description: Background: Feedback proves to be a valuable tool in behaviour change as it is said to increase compliance and improve the effectiveness of interventions. Interventions that focus on decreasing sedentary behaviour as an independent factor from physical activity are necessary, especially for office workers who spend most of their day seated. There is insufficient knowledge regarding the effectiveness of feedback as a tool to decrease sedentary behaviour. This project implemented a tool that can be used to determine this. To take advantage of the cost-effectiveness and scalability of digital technologies, a mobile application was selected as the mode of delivery. Method: The application was designed as an intervention, using the Theoretical Domains Framework. It was then implemented into a fully functioning application through an agile development process, using Xam- arin.Forms framework. Due to challenges with this framework, a second application was developed using the React Native framework. Pilot studies were used for testing, with the final one consisting of Rhodes University employees. Results: The Xamarin.Forms application proved to be unfeasible; some users experienced fatal errors and crashes. The React Native application worked as desired and produced accurate and consistent step count readings, proving feasible from a functionality standpoint. The agile methodology enabled the developer to focus on implementing and testing one component at a time, which made the development process more manageable. Conclusion: Future work must conduct empirical studies to determine if feedback is an effective tool compared to a control group and which type of feedback (between goal-setting and social comparison) is most effective. , Thesis (MSc) -- Faculty of Science, Computer Science, 2022
- Full Text:
- Date Issued: 2022-10-14
- Authors: Tsaoane, Moipone Lipalesa
- Date: 2022-10-14
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/365544 , vital:65758
- Description: Background: Feedback proves to be a valuable tool in behaviour change as it is said to increase compliance and improve the effectiveness of interventions. Interventions that focus on decreasing sedentary behaviour as an independent factor from physical activity are necessary, especially for office workers who spend most of their day seated. There is insufficient knowledge regarding the effectiveness of feedback as a tool to decrease sedentary behaviour. This project implemented a tool that can be used to determine this. To take advantage of the cost-effectiveness and scalability of digital technologies, a mobile application was selected as the mode of delivery. Method: The application was designed as an intervention, using the Theoretical Domains Framework. It was then implemented into a fully functioning application through an agile development process, using Xam- arin.Forms framework. Due to challenges with this framework, a second application was developed using the React Native framework. Pilot studies were used for testing, with the final one consisting of Rhodes University employees. Results: The Xamarin.Forms application proved to be unfeasible; some users experienced fatal errors and crashes. The React Native application worked as desired and produced accurate and consistent step count readings, proving feasible from a functionality standpoint. The agile methodology enabled the developer to focus on implementing and testing one component at a time, which made the development process more manageable. Conclusion: Future work must conduct empirical studies to determine if feedback is an effective tool compared to a control group and which type of feedback (between goal-setting and social comparison) is most effective. , Thesis (MSc) -- Faculty of Science, Computer Science, 2022
- Full Text:
- Date Issued: 2022-10-14
Beyond benefit sharing: Place attachment and the importance of access to protected areas for surrounding communities
- Cundill, Georgina, Bezerra, Joana C, de Vos, Alta, Ntingana, Nokuthula
- Authors: Cundill, Georgina , Bezerra, Joana C , de Vos, Alta , Ntingana, Nokuthula
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/416265 , vital:71334 , xlink:href="https://doi.org/10.1016/j.ecoser.2017.03.011"
- Description: The concept of place attachment can assist to integrate relational values into ecosystem service research, and assist us to rethink the notion of benefits in contemporary protected area thinking. We present a case study from South Africa, where the concept of two-dimensional place attachment was used to understand the relationship between a protected area and a land claimant community that now owns part of this protected area but does not have physical access to the land. A place attachment lens helps refocus access to protected areas as cornerstone to long term sustainability of such areas. Such access must be considered in the context of spatially and economically differentiated users, including a focus on trade-offs between such users. Our findings highlight that when communities previously displaced from protected areas respond to offers of ‘benefit sharing’ with demands for access and recognition as land owners, they are asking for a recognition of relational values, and identity, based on close interaction with nature. A place attachment and relational values perspective raises questions about the extent to which traditional conservation practice can accommodate such values, and therefore meet local people’s expectations and remain viable in the long term.
- Full Text:
- Date Issued: 2017
- Authors: Cundill, Georgina , Bezerra, Joana C , de Vos, Alta , Ntingana, Nokuthula
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/416265 , vital:71334 , xlink:href="https://doi.org/10.1016/j.ecoser.2017.03.011"
- Description: The concept of place attachment can assist to integrate relational values into ecosystem service research, and assist us to rethink the notion of benefits in contemporary protected area thinking. We present a case study from South Africa, where the concept of two-dimensional place attachment was used to understand the relationship between a protected area and a land claimant community that now owns part of this protected area but does not have physical access to the land. A place attachment lens helps refocus access to protected areas as cornerstone to long term sustainability of such areas. Such access must be considered in the context of spatially and economically differentiated users, including a focus on trade-offs between such users. Our findings highlight that when communities previously displaced from protected areas respond to offers of ‘benefit sharing’ with demands for access and recognition as land owners, they are asking for a recognition of relational values, and identity, based on close interaction with nature. A place attachment and relational values perspective raises questions about the extent to which traditional conservation practice can accommodate such values, and therefore meet local people’s expectations and remain viable in the long term.
- Full Text:
- Date Issued: 2017
Exploring the effect of the indigenous technology of oil extraction on Grade 10 Biology learners’ perspectives and sense making of enzymes
- Authors: Nyamakuti, Martha Ndeyatila
- Date: 2021-10-29
- Subjects: Biology Study and teaching (Secondary) , Enzymes , Traditional ecological knowledge Namibia , Culturally relevant pedagogy Namibia , Reasoning , Contiguity Argumentation Theory (CAT) , Namibian National Curriculum for Basic Education(NCBE) , Socio-cultural theory
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192019 , vital:45188
- Description: The current status quo is that African learners’ local indigenous knowledge (IK) and experiences from home (cultural heritage) are not considered in science classrooms. In the context of Namibia, it seems that the Namibian curriculum policies do little or nothing to decolonise and address the issues of equity and social injustice in Namibian schools. For instance, although the Namibian National Curriculum for Basic Education (NCBE) claims that it “embraces traditional knowledge”, it does not specify how this should be done in schools. As a result, little or no integration of IK is enacted in many of our schools in Namibia. Resultantly, learners seem to find science inaccessible and irrelevant to their everyday lives. It is against this background that in this study I sought to explore how the mobilisation of the indigenous technology of oil extraction (okuyenga) from marula nuts and melon seeds influences (or not) Grade 10 Biology learners’ conceptions, dispositions and sense making of the topic of enzymes. The study was located within the interpretive and indigenous research paradigms. Central to the interpretive paradigm is the development of a greater understanding of how people make sense of the contexts in which they live and work. On the other hand, central to indigenous research paradigms are belief systems based on the lived experiences, values, and histories of the participants. The Ubuntu perspective or approach in which respect and humble togetherness is emphasised is critical in indigenous research paradigms especially when researchers are working with and in communities as I did in this study. The study was conducted in an under resourced school in Walvis Bay, Namibia. A qualitative case study approach was used and data were derived from a focus group interview, participatory classroom observations, learners’ reflections, and a stimulated recall interview. Vygotsky’s socio-cultural theory was employed as a theoretical framework. Within the socio-cultural theory, mediation of learning, social interactions, and the zone of proximal development (ZPD) were used as analytical lenses. The conceptual framework comprised of perspectives (conceptions, dispositions) and sense making of enzymes by the learners. Criteria were also adapted from Atallah, Bryant, and Dada to analyse learners’ perspectives. A thematic approach to analysis was employed to come up with categories and sub-themes and thereafter, common sub-themes were combined to form themes. The findings of the study revealed that the presentations on the indigenous technology of oil extraction by the expert community members influenced learners’ conceptions, dispositions, and sense making of enzymes and other associated science concepts. This was noticed when learners extracted emerging science concepts from the indigenous technology of oil extraction. The implication of this study is that there is a need for science teachers to consider learners’ cultural heritage and integrate local IK in their Biology classrooms in order to make science accessible and relevant to learners. Moreover, the integration of local IK is critical for learners to embrace and respect their cultural heritage. This study thus recommends that teachers should make efforts to collaborate with expert community members who are the custodians of local IK and tap into their cultural heritage and wisdom to enrich teaching in their science classrooms. , Thesis (MEd) -- Faculty of Education, Education, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Nyamakuti, Martha Ndeyatila
- Date: 2021-10-29
- Subjects: Biology Study and teaching (Secondary) , Enzymes , Traditional ecological knowledge Namibia , Culturally relevant pedagogy Namibia , Reasoning , Contiguity Argumentation Theory (CAT) , Namibian National Curriculum for Basic Education(NCBE) , Socio-cultural theory
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192019 , vital:45188
- Description: The current status quo is that African learners’ local indigenous knowledge (IK) and experiences from home (cultural heritage) are not considered in science classrooms. In the context of Namibia, it seems that the Namibian curriculum policies do little or nothing to decolonise and address the issues of equity and social injustice in Namibian schools. For instance, although the Namibian National Curriculum for Basic Education (NCBE) claims that it “embraces traditional knowledge”, it does not specify how this should be done in schools. As a result, little or no integration of IK is enacted in many of our schools in Namibia. Resultantly, learners seem to find science inaccessible and irrelevant to their everyday lives. It is against this background that in this study I sought to explore how the mobilisation of the indigenous technology of oil extraction (okuyenga) from marula nuts and melon seeds influences (or not) Grade 10 Biology learners’ conceptions, dispositions and sense making of the topic of enzymes. The study was located within the interpretive and indigenous research paradigms. Central to the interpretive paradigm is the development of a greater understanding of how people make sense of the contexts in which they live and work. On the other hand, central to indigenous research paradigms are belief systems based on the lived experiences, values, and histories of the participants. The Ubuntu perspective or approach in which respect and humble togetherness is emphasised is critical in indigenous research paradigms especially when researchers are working with and in communities as I did in this study. The study was conducted in an under resourced school in Walvis Bay, Namibia. A qualitative case study approach was used and data were derived from a focus group interview, participatory classroom observations, learners’ reflections, and a stimulated recall interview. Vygotsky’s socio-cultural theory was employed as a theoretical framework. Within the socio-cultural theory, mediation of learning, social interactions, and the zone of proximal development (ZPD) were used as analytical lenses. The conceptual framework comprised of perspectives (conceptions, dispositions) and sense making of enzymes by the learners. Criteria were also adapted from Atallah, Bryant, and Dada to analyse learners’ perspectives. A thematic approach to analysis was employed to come up with categories and sub-themes and thereafter, common sub-themes were combined to form themes. The findings of the study revealed that the presentations on the indigenous technology of oil extraction by the expert community members influenced learners’ conceptions, dispositions, and sense making of enzymes and other associated science concepts. This was noticed when learners extracted emerging science concepts from the indigenous technology of oil extraction. The implication of this study is that there is a need for science teachers to consider learners’ cultural heritage and integrate local IK in their Biology classrooms in order to make science accessible and relevant to learners. Moreover, the integration of local IK is critical for learners to embrace and respect their cultural heritage. This study thus recommends that teachers should make efforts to collaborate with expert community members who are the custodians of local IK and tap into their cultural heritage and wisdom to enrich teaching in their science classrooms. , Thesis (MEd) -- Faculty of Education, Education, 2021
- Full Text:
- Date Issued: 2021-10-29
A decision-making model to guide securing blockchain deployments
- Authors: Cronje, Gerhard Roets
- Date: 2021-10-29
- Subjects: Blockchains (Databases) , Bitcoin , Cryptocurrencies , Distributed databases , Computer networks Security measures , Computer networks Security measures Decision making , Ethereum
- Language: English
- Type: Masters theses , text
- Identifier: http://hdl.handle.net/10962/188865 , vital:44793
- Description: Satoshi Nakamoto, the pseudo-identity accredit with the paper that sparked the implementation of Bitcoin, is famously quoted as remarking, electronically of course, that “If you don’t believe it or don’t get it, I don’t have time to try and convince you, sorry” (Tsapis, 2019, p. 1). What is noticeable, 12 years after the famed Satoshi paper that initiated Bitcoin (Nakamoto, 2008), is that blockchain at the very least has staying power and potentially wide application. A lesser known figure Marc Kenisberg, founder of Bitcoin Chaser which is one of the many companies formed around the Bitcoin ecosystem, summarised it well saying “…Blockchain is the tech - Bitcoin is merely the first mainstream manifestation of its potential” (Tsapis, 2019, p. 1). With blockchain still trying to reach its potential and still maturing on its way towards a mainstream technology the main question that arises for security professionals is how do I ensure we do it securely? This research seeks to address that question by proposing a decision-making model that can be used by a security professional to guide them through ensuring appropriate security for blockchain deployments. This research is certainly not the first attempt at discussing the security of the blockchain and will not be the last, as the technology around blockchain and distributed ledger technology is still rapidly evolving. What this research does try to achieve is not to delve into extremely specific areas of blockchain security, or get bogged down in technical details, but to provide a reference framework that aims to cover all the major areas to be considered. The approach followed was to review the literature regarding blockchain and to identify the main security areas to be addressed. It then proposes a decision-making model and tests the model against a fictitious but relevant real-world example. It concludes with learnings from this research. The reader can be the judge, but the model aims to be a practical valuable resource to be used by any security professional, to navigate the security aspects logically and understandably when being involved in a blockchain deployment. In contrast to the Satoshi quote, this research tries to convince the reader and assist him/her in understanding the security choices related to every blockchain deployment. , Thesis (MSc) -- Faculty of Science, Computer Science, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Cronje, Gerhard Roets
- Date: 2021-10-29
- Subjects: Blockchains (Databases) , Bitcoin , Cryptocurrencies , Distributed databases , Computer networks Security measures , Computer networks Security measures Decision making , Ethereum
- Language: English
- Type: Masters theses , text
- Identifier: http://hdl.handle.net/10962/188865 , vital:44793
- Description: Satoshi Nakamoto, the pseudo-identity accredit with the paper that sparked the implementation of Bitcoin, is famously quoted as remarking, electronically of course, that “If you don’t believe it or don’t get it, I don’t have time to try and convince you, sorry” (Tsapis, 2019, p. 1). What is noticeable, 12 years after the famed Satoshi paper that initiated Bitcoin (Nakamoto, 2008), is that blockchain at the very least has staying power and potentially wide application. A lesser known figure Marc Kenisberg, founder of Bitcoin Chaser which is one of the many companies formed around the Bitcoin ecosystem, summarised it well saying “…Blockchain is the tech - Bitcoin is merely the first mainstream manifestation of its potential” (Tsapis, 2019, p. 1). With blockchain still trying to reach its potential and still maturing on its way towards a mainstream technology the main question that arises for security professionals is how do I ensure we do it securely? This research seeks to address that question by proposing a decision-making model that can be used by a security professional to guide them through ensuring appropriate security for blockchain deployments. This research is certainly not the first attempt at discussing the security of the blockchain and will not be the last, as the technology around blockchain and distributed ledger technology is still rapidly evolving. What this research does try to achieve is not to delve into extremely specific areas of blockchain security, or get bogged down in technical details, but to provide a reference framework that aims to cover all the major areas to be considered. The approach followed was to review the literature regarding blockchain and to identify the main security areas to be addressed. It then proposes a decision-making model and tests the model against a fictitious but relevant real-world example. It concludes with learnings from this research. The reader can be the judge, but the model aims to be a practical valuable resource to be used by any security professional, to navigate the security aspects logically and understandably when being involved in a blockchain deployment. In contrast to the Satoshi quote, this research tries to convince the reader and assist him/her in understanding the security choices related to every blockchain deployment. , Thesis (MSc) -- Faculty of Science, Computer Science, 2021
- Full Text:
- Date Issued: 2021-10-29
Photodynamic therapy activity of zinc phthalocyanine linked to folic acid and magnetic nanoparticles
- Matlou, Gauta G, Oluwole, David O, Prinsloo, Earl, Nyokong, Tebello
- Authors: Matlou, Gauta G , Oluwole, David O , Prinsloo, Earl , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/234429 , vital:50195 , xlink:href="https://doi.org/10.1016/j.jphotobiol.2018.07.025"
- Description: In this work, the photodynamic therapy (PDT) activities (using human carcinoma adherent MCF-7 cells) of zinc phthalocyanine derivatives: complexes 1 (Zn mono cinnamic acid phthalocyanine) and 2 (zinc mono carboxyphenoxy phthalocyanine) when covalently linked to folic acid (FA) and amine functionalized magnetic nanoparticles (AMNPs) are reported. The covalent linkage of asymmetric zinc cinnamic acid Pc (1) to FA (1-FA) through an amide bond is reported for the first time. Complex 1 is insoluble in water, but upon linkage to FA, (to form 1-FA) the molecule become water soluble, hence the UV–Vis spectrum and singlet oxygen quantum yield for 1-FA were also done in water since water solubility is essential for biological applications. The reported 2-FA is also water soluble. Linking complexes 1 and 2 to FA and AMNPs decreased the dark toxicity of 1 and 2 on MCF-7 cells. Pc-FA (1-FA and 2-FA) conjugates had better singlet oxygen quantum yields (Φ∆) in DMSO as compared to Pc-AMNPs (1-AMNPs and 2-AMNPs). The water- soluble 1-FA and 2-FA also achieved a better photodynamic therapy (PDT) activity as compared to 1-AMNPs and 2-AMNPs. Folic acid targeting on the tumor cells may have also facilitated better bioavailability of 1-FA and 2-FA and improved PDT activity on MCF-7 cells over AMNPs carriers.
- Full Text:
- Date Issued: 2018
Photodynamic therapy activity of zinc phthalocyanine linked to folic acid and magnetic nanoparticles
- Authors: Matlou, Gauta G , Oluwole, David O , Prinsloo, Earl , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/234429 , vital:50195 , xlink:href="https://doi.org/10.1016/j.jphotobiol.2018.07.025"
- Description: In this work, the photodynamic therapy (PDT) activities (using human carcinoma adherent MCF-7 cells) of zinc phthalocyanine derivatives: complexes 1 (Zn mono cinnamic acid phthalocyanine) and 2 (zinc mono carboxyphenoxy phthalocyanine) when covalently linked to folic acid (FA) and amine functionalized magnetic nanoparticles (AMNPs) are reported. The covalent linkage of asymmetric zinc cinnamic acid Pc (1) to FA (1-FA) through an amide bond is reported for the first time. Complex 1 is insoluble in water, but upon linkage to FA, (to form 1-FA) the molecule become water soluble, hence the UV–Vis spectrum and singlet oxygen quantum yield for 1-FA were also done in water since water solubility is essential for biological applications. The reported 2-FA is also water soluble. Linking complexes 1 and 2 to FA and AMNPs decreased the dark toxicity of 1 and 2 on MCF-7 cells. Pc-FA (1-FA and 2-FA) conjugates had better singlet oxygen quantum yields (Φ∆) in DMSO as compared to Pc-AMNPs (1-AMNPs and 2-AMNPs). The water- soluble 1-FA and 2-FA also achieved a better photodynamic therapy (PDT) activity as compared to 1-AMNPs and 2-AMNPs. Folic acid targeting on the tumor cells may have also facilitated better bioavailability of 1-FA and 2-FA and improved PDT activity on MCF-7 cells over AMNPs carriers.
- Full Text:
- Date Issued: 2018
Being moved by a way the world is not
- Authors: Jones, Ward E
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/275631 , vital:55064 , xlink:href="https://doi.org/10.1007/s11229-009-9522-z"
- Description: At the end of Lecture 3 of The Empirical Stance, Bas van Fraassen suggests that we see the change of view involved in scientific revolutions as being, at least in part, emotional. In this paper, I explore one plausible way of cashing out this suggestion. Someone’s emotional approval of a description of the world, I argue, thereby shows that she takes herself to have reason to take that description seriously. This is true even if she is convinced—as a scientific community is when it considers alternative theories—that this description is false, that it is not the way the world is.
- Full Text:
- Date Issued: 2011
- Authors: Jones, Ward E
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/275631 , vital:55064 , xlink:href="https://doi.org/10.1007/s11229-009-9522-z"
- Description: At the end of Lecture 3 of The Empirical Stance, Bas van Fraassen suggests that we see the change of view involved in scientific revolutions as being, at least in part, emotional. In this paper, I explore one plausible way of cashing out this suggestion. Someone’s emotional approval of a description of the world, I argue, thereby shows that she takes herself to have reason to take that description seriously. This is true even if she is convinced—as a scientific community is when it considers alternative theories—that this description is false, that it is not the way the world is.
- Full Text:
- Date Issued: 2011
Wisdom as an aim of higher education
- Authors: Jones, Ward E
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/275765 , vital:55077 , xlink:href="https://doi.org/10.1007/s10790-014-9443-z"
- Description: A central concern of theoretical speculation about education is the kind of epistemic states that education can and should aim to achieve. One such epistemic state, long neglected in both education theory and philosophy, is wisdom. Might wisdom be something that educators should aim for? And might it be something that their students can achieve? My answer will be a qualified yes.
- Full Text:
- Date Issued: 2015
- Authors: Jones, Ward E
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/275765 , vital:55077 , xlink:href="https://doi.org/10.1007/s10790-014-9443-z"
- Description: A central concern of theoretical speculation about education is the kind of epistemic states that education can and should aim to achieve. One such epistemic state, long neglected in both education theory and philosophy, is wisdom. Might wisdom be something that educators should aim for? And might it be something that their students can achieve? My answer will be a qualified yes.
- Full Text:
- Date Issued: 2015
Study South Africa
- International Education Association of South Africa (IEASA), Jooste, Nico
- Authors: International Education Association of South Africa (IEASA) , Jooste, Nico
- Date: 2010
- Subjects: Education, Higher -- South Africa , Universities and colleges -- South Africa , Technical Institutes -- South Africa , Vocational guidance -- South Africa
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/64963 , vital:28640 , ISBN 9780620482172
- Description: [Extract from message from Minister of Higher Education and Training, Hon. Dr BE Nzimande]: The 10th Edition focuses on the highly relevant issue of ‘Higher Education Internationalisation in the Development of Africa’. The internationalisation of higher education is of great importance for the continent, if Africa wants to be able to compete and participate in a global context. Currently, there are only three African institutions in the Top 500 of the Shanghai Academic Ranking of World Universities and all of these are in South Africa. Similarly, one South African institution appears in the Top 200 of the Times Higher Education World Ranking and no other African universities are represented. Despite being cautious about the methodology used to derive rankings, our aim in higher education should be to actively compete internationally and, more importantly, to serve the developmental challenges of Africa. It is imperative that Africa engages internationally and participates in the development of humanity’s knowledge. Research outputs and publications are particularly low on the continent, and African universities need to develop their research capabilities and direct resources to this important function. It is particularly important that research, which affects Africa and its development, is conducted on a large scale on the continent, supported by collaborative work and partnerships, rather than being carried out predominantly in other countries. The time has come for the tide to change and for our researchers and academics to focus on research opportunities presented on the continent. This is an important step for Africa to take if it is to deal effectively with the problems it faces and take its place in the international arena. One way to increase and develop knowledge outputs is through collaboration. An important opportunity for South African universities is the Erasmus Mundus Programme funded through the European Union (EU). This programme encourages collaboration between South African and European universities and provides resources for the exchange of staff and students within specific research programmes. It is also important for Africa to develop the research collaboration within the continent and with other developing and developed countries. In this regard, the Intra-ACP (Africa-Caribbean-Pacific) Scheme is of great importance. This initiative by the African Union (AU), working in collaboration with the EU, provides the opportunity for academic staff and student exchanges between universities in these regions. Intra-African exchanges are of particular importance in developing the continent’s capacity. Through such programmes African universities can work together to develop research and participate in the knowledge economy. We should also not ignore the challenges faced in improving the quality of teaching and learning in African universities, including many in South Africa. If sufficient attention and resources are not directed to improving these most basic activities of higher education, we will not only fail to meet the continent’s human resource development needs, but we will fail to establish the basis for future research advancement. Student mobility is very much a part of our fabric and provides the necessary intellectual stimulation, which is an essential part of student life. The number of African students from outside South Africa studying at South African institutions is growing annually, as is the number of non-African students. The networks established through such internationalisation are invaluable. There are also large numbers of our own students who, through universities’ reciprocal agreements, are studying abroad. The information provided in this publication provides a valuable opportunity to showcase our higher education sector and goes a long way to providing the necessary facts to encourage such student mobility. , 10th Edition
- Full Text:
- Date Issued: 2010
- Authors: International Education Association of South Africa (IEASA) , Jooste, Nico
- Date: 2010
- Subjects: Education, Higher -- South Africa , Universities and colleges -- South Africa , Technical Institutes -- South Africa , Vocational guidance -- South Africa
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/64963 , vital:28640 , ISBN 9780620482172
- Description: [Extract from message from Minister of Higher Education and Training, Hon. Dr BE Nzimande]: The 10th Edition focuses on the highly relevant issue of ‘Higher Education Internationalisation in the Development of Africa’. The internationalisation of higher education is of great importance for the continent, if Africa wants to be able to compete and participate in a global context. Currently, there are only three African institutions in the Top 500 of the Shanghai Academic Ranking of World Universities and all of these are in South Africa. Similarly, one South African institution appears in the Top 200 of the Times Higher Education World Ranking and no other African universities are represented. Despite being cautious about the methodology used to derive rankings, our aim in higher education should be to actively compete internationally and, more importantly, to serve the developmental challenges of Africa. It is imperative that Africa engages internationally and participates in the development of humanity’s knowledge. Research outputs and publications are particularly low on the continent, and African universities need to develop their research capabilities and direct resources to this important function. It is particularly important that research, which affects Africa and its development, is conducted on a large scale on the continent, supported by collaborative work and partnerships, rather than being carried out predominantly in other countries. The time has come for the tide to change and for our researchers and academics to focus on research opportunities presented on the continent. This is an important step for Africa to take if it is to deal effectively with the problems it faces and take its place in the international arena. One way to increase and develop knowledge outputs is through collaboration. An important opportunity for South African universities is the Erasmus Mundus Programme funded through the European Union (EU). This programme encourages collaboration between South African and European universities and provides resources for the exchange of staff and students within specific research programmes. It is also important for Africa to develop the research collaboration within the continent and with other developing and developed countries. In this regard, the Intra-ACP (Africa-Caribbean-Pacific) Scheme is of great importance. This initiative by the African Union (AU), working in collaboration with the EU, provides the opportunity for academic staff and student exchanges between universities in these regions. Intra-African exchanges are of particular importance in developing the continent’s capacity. Through such programmes African universities can work together to develop research and participate in the knowledge economy. We should also not ignore the challenges faced in improving the quality of teaching and learning in African universities, including many in South Africa. If sufficient attention and resources are not directed to improving these most basic activities of higher education, we will not only fail to meet the continent’s human resource development needs, but we will fail to establish the basis for future research advancement. Student mobility is very much a part of our fabric and provides the necessary intellectual stimulation, which is an essential part of student life. The number of African students from outside South Africa studying at South African institutions is growing annually, as is the number of non-African students. The networks established through such internationalisation are invaluable. There are also large numbers of our own students who, through universities’ reciprocal agreements, are studying abroad. The information provided in this publication provides a valuable opportunity to showcase our higher education sector and goes a long way to providing the necessary facts to encourage such student mobility. , 10th Edition
- Full Text:
- Date Issued: 2010
Religiosity and sexual risk-taking behaviour among Black female students attending university
- Authors: Yona, Nombeko
- Date: 2009-02
- Subjects: College students -- Sexual behavior , Women college students , Risk-taking (Psychology)
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10353/25129 , vital:63980
- Description: The degree to which religious identity acts as a protective buffer against sexual risk - taking in late adolescence and young adults was investigated among 100 Black female university students. Allport and Ross’ Religious Orientation Scale was used to examine the relationship among religiosity, sexual activity and condom use. The results indicated that greater intrinsic and extrinsic religiosity were associated with less sexual activity and condom use. Religious identification therefore protected respondents from sexual risk- taking but sexually active students with high levels of intrinsic and extrinsic religiosity were less likely to use condoms. , Thesis (MSoc) -- Faculty of Social Sciences and Humanities, 2009
- Full Text:
- Date Issued: 2009-02
- Authors: Yona, Nombeko
- Date: 2009-02
- Subjects: College students -- Sexual behavior , Women college students , Risk-taking (Psychology)
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10353/25129 , vital:63980
- Description: The degree to which religious identity acts as a protective buffer against sexual risk - taking in late adolescence and young adults was investigated among 100 Black female university students. Allport and Ross’ Religious Orientation Scale was used to examine the relationship among religiosity, sexual activity and condom use. The results indicated that greater intrinsic and extrinsic religiosity were associated with less sexual activity and condom use. Religious identification therefore protected respondents from sexual risk- taking but sexually active students with high levels of intrinsic and extrinsic religiosity were less likely to use condoms. , Thesis (MSoc) -- Faculty of Social Sciences and Humanities, 2009
- Full Text:
- Date Issued: 2009-02
(Ferrocenylpyrazolyl) zinc (II) benzoates as catalysts for the ring opening polymerization of ε-caprolactone
- Obuah, Collins, Lochee, Yemanlall, Jordaan, Johan H L, Otto, Daniel P, Nyokong, Tebello, Darkwa, James
- Authors: Obuah, Collins , Lochee, Yemanlall , Jordaan, Johan H L , Otto, Daniel P , Nyokong, Tebello , Darkwa, James
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189515 , vital:44853 , xlink:href="https://doi.org/10.1016/j.poly.2015.02.007"
- Description: The reaction of Zn(OAc)2 and C6H5COOH or 3,5-NO2-C6H3COOH with 3-ferrocenylpyrazolyl-methylenepyridine (L1), 3-ferrocenyl-5-methylpyrazolyl-methylenepyridine (L2), 3-ferrocenylpyrazolyl-ethylamine (L3) and 3-ferrocenyl-5-pyrazolyl-ethylamine (L4) afford the corresponding complexes [Zn(C6H5COO)2(L1)] (1), [Zn(C6H5COO)2(L2)] (2), [Zn(3,5-NO2-C6H3COO)2(L1)] (3), [Zn(3,5-NO2-C6H3 COO)2(L2)] (4), [Zn(C6H5COO)2(L3)] (5), [Zn(C6H5COO)2(L4)] (6), [Zn(3,5-NO2-C6H3COO)2(L3)] (7) and [Zn(3,5-NO2-C6H3COO)2(L4)] (8). These complexes behave as catalysts for the ring opening polymerization of e-caprolactone to produce polymers with molecular weight that range from 1480 to 7080 g mol1 and exhibited moderate to broad PDIs. Evidence of these complexes acting as catalysts was obtained from both the polymerization data and kinetic studies. The polymerization data show that variation of the [CL]/[C] from 100 to 800 produced PCL with relatively the same molecular weight indicative of a catalyst behavior. The appearance of induction period in kinetic plots strengthens the fact that these complexes are catalysts rather than initiators. MALDI-TOF MS and 1 H NMR data show di-hydroxy end groups, which support the coordination mechanism rather than insertion mechanism. To understand the broad PDIs obtained for some of the polymer, the electronic properties of the zinc complexes were investigated using cyclic voltammetry. The results show that the zinc complexes containing amine based ligands are highly electrophilic therefore making them unstable, hence the broad PDIs observed for zinc complexes containing amine based ligands. Among the eight complexes investigated, complex 7 is the most active catalyst with kp value of 1.18 107 h1 mol1 at 110 C.
- Full Text:
- Date Issued: 2015
- Authors: Obuah, Collins , Lochee, Yemanlall , Jordaan, Johan H L , Otto, Daniel P , Nyokong, Tebello , Darkwa, James
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189515 , vital:44853 , xlink:href="https://doi.org/10.1016/j.poly.2015.02.007"
- Description: The reaction of Zn(OAc)2 and C6H5COOH or 3,5-NO2-C6H3COOH with 3-ferrocenylpyrazolyl-methylenepyridine (L1), 3-ferrocenyl-5-methylpyrazolyl-methylenepyridine (L2), 3-ferrocenylpyrazolyl-ethylamine (L3) and 3-ferrocenyl-5-pyrazolyl-ethylamine (L4) afford the corresponding complexes [Zn(C6H5COO)2(L1)] (1), [Zn(C6H5COO)2(L2)] (2), [Zn(3,5-NO2-C6H3COO)2(L1)] (3), [Zn(3,5-NO2-C6H3 COO)2(L2)] (4), [Zn(C6H5COO)2(L3)] (5), [Zn(C6H5COO)2(L4)] (6), [Zn(3,5-NO2-C6H3COO)2(L3)] (7) and [Zn(3,5-NO2-C6H3COO)2(L4)] (8). These complexes behave as catalysts for the ring opening polymerization of e-caprolactone to produce polymers with molecular weight that range from 1480 to 7080 g mol1 and exhibited moderate to broad PDIs. Evidence of these complexes acting as catalysts was obtained from both the polymerization data and kinetic studies. The polymerization data show that variation of the [CL]/[C] from 100 to 800 produced PCL with relatively the same molecular weight indicative of a catalyst behavior. The appearance of induction period in kinetic plots strengthens the fact that these complexes are catalysts rather than initiators. MALDI-TOF MS and 1 H NMR data show di-hydroxy end groups, which support the coordination mechanism rather than insertion mechanism. To understand the broad PDIs obtained for some of the polymer, the electronic properties of the zinc complexes were investigated using cyclic voltammetry. The results show that the zinc complexes containing amine based ligands are highly electrophilic therefore making them unstable, hence the broad PDIs observed for zinc complexes containing amine based ligands. Among the eight complexes investigated, complex 7 is the most active catalyst with kp value of 1.18 107 h1 mol1 at 110 C.
- Full Text:
- Date Issued: 2015
Representation of the twentieth century socio-economic and political history of Red Location New Brighton (Port Elizabeth) 1903-1963
- Authors: Maliza, Nokuzola Thozama
- Date: 2012-01
- Subjects: History -- Economic conditions , World politics -- South Africa , Squatter settlements -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/26415 , vital:65306
- Description: This study sets out to recapture the rich history and diverse culture of Red Location, New Brighton. Port Elizabeth. It explains the reasons for the establishment of Red Location in 1903, and goes on to look at the Economic and Social life of the Community. Two chapters are then devoted to political struggles in Red Location and New Brighton, long regarded as one of the most militant African townships in the apartheid era. Finally, we look at the way in which Red Location has been represented in the substantial Red Location Museum project, and the extent to which the Museum reflects the historical reality. , Thesis (MHIS) -- Faculty of Humanities, 2012
- Full Text:
- Date Issued: 2012-01
- Authors: Maliza, Nokuzola Thozama
- Date: 2012-01
- Subjects: History -- Economic conditions , World politics -- South Africa , Squatter settlements -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/26415 , vital:65306
- Description: This study sets out to recapture the rich history and diverse culture of Red Location, New Brighton. Port Elizabeth. It explains the reasons for the establishment of Red Location in 1903, and goes on to look at the Economic and Social life of the Community. Two chapters are then devoted to political struggles in Red Location and New Brighton, long regarded as one of the most militant African townships in the apartheid era. Finally, we look at the way in which Red Location has been represented in the substantial Red Location Museum project, and the extent to which the Museum reflects the historical reality. , Thesis (MHIS) -- Faculty of Humanities, 2012
- Full Text:
- Date Issued: 2012-01
Electrocatalytic oxidation of cysteine by molybdenum (V) phthalocyanine complexes
- Mafatle, Tsukutlane J, Nyokong, Tebello
- Authors: Mafatle, Tsukutlane J , Nyokong, Tebello
- Date: 1996
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293369 , vital:57079 , xlink:href="https://doi.org/10.1016/0022-0728(95)04519-8"
- Description: Chemically modified electrodes, constructed by incorporating oxomolybdenum(V) phthalocyanine (OMo(V)(OH)Pc, Pc = phthalocyanine dianion) into graphite powder were used to catalyse the oxidation of cysteine. Solution catalysis of cysteine by oxomolybdenum(V) tetrasulfophthalocyanine, [OMo(V)(OH)TSPc]4−, was also investigated. A considerable reduction in overpotential for cysteine oxidation was observed. Cysteine oxidation occurred at 0.26 and 0.28 V vs. Ag/vbAgCl for catalysis by Omo(V)(OH)Pc and [OMo(V)(OH)TSPc]4− respectively as opposed to 0.77 V vs. Ag/vbAgCl observed on CoPc chemically modified electrodes. The anodic peak currents vary linearly with cysteine concentration in the range 0.02 to 0.08 mol dm−3 and 0.008 to 0.02 mol dm−3 for [OMo(V)(OH)TSPc]4− and OMo(V)Pc respectively.
- Full Text:
- Date Issued: 1996
- Authors: Mafatle, Tsukutlane J , Nyokong, Tebello
- Date: 1996
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293369 , vital:57079 , xlink:href="https://doi.org/10.1016/0022-0728(95)04519-8"
- Description: Chemically modified electrodes, constructed by incorporating oxomolybdenum(V) phthalocyanine (OMo(V)(OH)Pc, Pc = phthalocyanine dianion) into graphite powder were used to catalyse the oxidation of cysteine. Solution catalysis of cysteine by oxomolybdenum(V) tetrasulfophthalocyanine, [OMo(V)(OH)TSPc]4−, was also investigated. A considerable reduction in overpotential for cysteine oxidation was observed. Cysteine oxidation occurred at 0.26 and 0.28 V vs. Ag/vbAgCl for catalysis by Omo(V)(OH)Pc and [OMo(V)(OH)TSPc]4− respectively as opposed to 0.77 V vs. Ag/vbAgCl observed on CoPc chemically modified electrodes. The anodic peak currents vary linearly with cysteine concentration in the range 0.02 to 0.08 mol dm−3 and 0.008 to 0.02 mol dm−3 for [OMo(V)(OH)TSPc]4− and OMo(V)Pc respectively.
- Full Text:
- Date Issued: 1996
Fuel wood use in South Africa: Where to in the 21st Century?
- Williams, Anthony, Shackleton, Charlie M
- Authors: Williams, Anthony , Shackleton, Charlie M
- Date: 2002
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183026 , vital:43905 , xlink:href="https://doi.org/10.1080/20702620.2002.10434611"
- Description: South Africa is well known for the dichotomous nature of its economy, with its juxtaposed first and third world characteristics, perhaps nowhere more starkly evident than in the energy sector. South Africa produces and consumes over 60% of the total electrical energy on the African continent, and is ranked twelfth in the world in terms of carbon emissions (EIA, 2002). Yet the majority of the South African population does not have access to electricity, and despite the enormous strides taken since 1994 to increase household access to electricity (NER, 2001), newly electrified households, more often than not, cannot afford the appliances nor the monthly costs required to significantly improve their quality of life (White et al., 1997). Thus, most rural and many peri-urban households continue to use fuelwood as their primary energy source (Griffin et al., 1992; Dyer, 1996; Kotze, 1996; Williams et al., 1996). Fuelwood use presents both opportunities and risks.
- Full Text:
- Date Issued: 2002
- Authors: Williams, Anthony , Shackleton, Charlie M
- Date: 2002
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183026 , vital:43905 , xlink:href="https://doi.org/10.1080/20702620.2002.10434611"
- Description: South Africa is well known for the dichotomous nature of its economy, with its juxtaposed first and third world characteristics, perhaps nowhere more starkly evident than in the energy sector. South Africa produces and consumes over 60% of the total electrical energy on the African continent, and is ranked twelfth in the world in terms of carbon emissions (EIA, 2002). Yet the majority of the South African population does not have access to electricity, and despite the enormous strides taken since 1994 to increase household access to electricity (NER, 2001), newly electrified households, more often than not, cannot afford the appliances nor the monthly costs required to significantly improve their quality of life (White et al., 1997). Thus, most rural and many peri-urban households continue to use fuelwood as their primary energy source (Griffin et al., 1992; Dyer, 1996; Kotze, 1996; Williams et al., 1996). Fuelwood use presents both opportunities and risks.
- Full Text:
- Date Issued: 2002