Synthesis and characterization of titanium dioxide nanotubes on fluorine-doped tin oxide (FTO) glass substrate using electro-anodization technique
- Zinya, Simcelile https://orcid.org/0000-0001-5864-0957
- Authors: Zinya, Simcelile https://orcid.org/0000-0001-5864-0957
- Date: 2017-12
- Subjects: Titanium dioxide , Nanotubes , Nanostructured materials
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/23979 , vital:62201
- Description: One-dimensional (1-D) titanium dioxide nanotubes (TNTs) have attracted much attention as a promising alternative electrode material for dye sensitized solar cell (DSSC). As compared to the randomly packed and disordered TiO2 nanoparticles (TNPs) network with numerous particle-particle interfaces, TNTs prove to have fascinating features than make them suitable candidates in DSSCs. Well-structured TNTs arrays are of great potential among the various types of 1D TiO2 nano-materials owing to their superior electron transport properties with limited grain boundaries. Vectorial transport of photon generated electrons along the TNTs has been reported to lead to higher charge mobility which is crucial for improvement of DSSC performances. In this work, highly adhesive titanium films were deposited on functional substrates (FS) using radio frequency (RF) sputtering technique at a sputtering output power of 1kW, operating pressure of 1.5 Pa and at a deposition temperature of 200 °C to obtain a thickness of 10 μm under an inert argon atmosphere. The duration period for sputter coating 10 μm thickness of titanium film layer was 122 minutes with sputter rate for titanium target of about 82 nm per minutes. Subsequently, the RF sputtered titanium films were anodized with 0.5 wt. percent ammonium fluoride + 0.35 wt. percent deionised water and 96 wt. percent glycerol electrolyte solution at room temperature at 60 V for 72 hours. The resulting TNTs on functional substrates (TNTs-FS) were subjected to thermal treatment at 350 °C, 450 °C, 550 °C and 650 °C for 3 hours under oxygen atmosphere. The effect of annealing temperature on the morphological, and structural properties have been scrutinized. The as prepared and thermally treated TNTs-FS were characterized using scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD) and Confocal Raman Spectroscopy (CRS). SEM and HRTEM techniques were employed to confirm the presence of the TNTs-FS and also to study the structural-morphology of the TNTs as the annealing temperature increases. SEM revealed improvement in morphology with increase in sample annealing temperature, even at high temperatures such as 650 °C with no collapsing and sintering of the TNTs-FS occurring. SEM images revealed TNTs-FS with pore diameter sizes in the range between 85-170 nm. This is in compliance with HRTEM analysis, which revealed smooth and straight tube walls and improved surface morphology with increase in annealing temperature. In addition HRTEM images revealed pore diameter of TNTs-FS in the range between 85-165 nm. Furthermore, HRTEM revealed lattice fringes of 0.351, 0.352 and 0.353 nm between the neighbouring lattice fringes. All corresponding to (101) planes of anatase phase TNTs at different annealing temperatures (350-650 °C). The crystallographic structure of TNTs-FS was characterized by XRD measurements after thermal treatment at 350 °C, 450 °C, 550 °C and 650 °C. The XRD pattern revealed peaks in the wide angle range of 2θ (20° < 2θ > 80°) discovered at 29.43°, 45.10°, 56.52°, 63.5°, 64.92° and 74.81° corresponding to the planes (101), (112), (200), (105), (211) and (204) crystalline structures of the anatase TNTs. The intensity of the peaks increased with increasing annealing temperature. The strong sharp peaks indicate the large quantities and higher degrees of crystallinity of anatase phase of the TNTs. CRS Large Area Scan (LAS) and Depth profiling (DP) were employed to evaluate the crystallinity and phase distribution of TNTs-FS thermally treated at different temperatures. CRS LAS in the XY direction of TNTs-FS revealed the presence of differently crystallized anatase phases of TiO2 with Raman vibrational modes of 159.38 cm-1 (Eg), 208.37 cm-1 (Eg), 399.67 cm-1 (B1g), 514.25 cm-1 (A1g) and 641.58 cm-1 (Eg) for the samples annealed at 350 °C. The effect of annealing temperature on TiO2 phase evolution was meticulously evaluated using CRS for TNTs-FS for the samples annealed at 350 °C, 450 °C, 550 °C and 650 °C. The FWHM was estimated from CRS and decreases with increasing annealing temperature resulting in increasing crystallinity. Increase in anatase FWHM and anatase peak intensity implies higher degree of crystallinity and increasing crystallite sizes were also confirmed by XRD. Growing of titanium dioxide on functional substrates one novel contribution towards the fabrication of efficient electrode materials for solar cell development. Our method of characterizing TNTs-FS from a large area scan along the surface of the samples and depth profiling along the TNTs tube walls using confocal Raman spectroscopy prove to be a pivotal step in the development of efficient photoelectrode materials of the solar devices. , Thesis (MSc) -- Faculty of Science and Agriculture, 2017
- Full Text:
- Date Issued: 2017-12
- Authors: Zinya, Simcelile https://orcid.org/0000-0001-5864-0957
- Date: 2017-12
- Subjects: Titanium dioxide , Nanotubes , Nanostructured materials
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/23979 , vital:62201
- Description: One-dimensional (1-D) titanium dioxide nanotubes (TNTs) have attracted much attention as a promising alternative electrode material for dye sensitized solar cell (DSSC). As compared to the randomly packed and disordered TiO2 nanoparticles (TNPs) network with numerous particle-particle interfaces, TNTs prove to have fascinating features than make them suitable candidates in DSSCs. Well-structured TNTs arrays are of great potential among the various types of 1D TiO2 nano-materials owing to their superior electron transport properties with limited grain boundaries. Vectorial transport of photon generated electrons along the TNTs has been reported to lead to higher charge mobility which is crucial for improvement of DSSC performances. In this work, highly adhesive titanium films were deposited on functional substrates (FS) using radio frequency (RF) sputtering technique at a sputtering output power of 1kW, operating pressure of 1.5 Pa and at a deposition temperature of 200 °C to obtain a thickness of 10 μm under an inert argon atmosphere. The duration period for sputter coating 10 μm thickness of titanium film layer was 122 minutes with sputter rate for titanium target of about 82 nm per minutes. Subsequently, the RF sputtered titanium films were anodized with 0.5 wt. percent ammonium fluoride + 0.35 wt. percent deionised water and 96 wt. percent glycerol electrolyte solution at room temperature at 60 V for 72 hours. The resulting TNTs on functional substrates (TNTs-FS) were subjected to thermal treatment at 350 °C, 450 °C, 550 °C and 650 °C for 3 hours under oxygen atmosphere. The effect of annealing temperature on the morphological, and structural properties have been scrutinized. The as prepared and thermally treated TNTs-FS were characterized using scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD) and Confocal Raman Spectroscopy (CRS). SEM and HRTEM techniques were employed to confirm the presence of the TNTs-FS and also to study the structural-morphology of the TNTs as the annealing temperature increases. SEM revealed improvement in morphology with increase in sample annealing temperature, even at high temperatures such as 650 °C with no collapsing and sintering of the TNTs-FS occurring. SEM images revealed TNTs-FS with pore diameter sizes in the range between 85-170 nm. This is in compliance with HRTEM analysis, which revealed smooth and straight tube walls and improved surface morphology with increase in annealing temperature. In addition HRTEM images revealed pore diameter of TNTs-FS in the range between 85-165 nm. Furthermore, HRTEM revealed lattice fringes of 0.351, 0.352 and 0.353 nm between the neighbouring lattice fringes. All corresponding to (101) planes of anatase phase TNTs at different annealing temperatures (350-650 °C). The crystallographic structure of TNTs-FS was characterized by XRD measurements after thermal treatment at 350 °C, 450 °C, 550 °C and 650 °C. The XRD pattern revealed peaks in the wide angle range of 2θ (20° < 2θ > 80°) discovered at 29.43°, 45.10°, 56.52°, 63.5°, 64.92° and 74.81° corresponding to the planes (101), (112), (200), (105), (211) and (204) crystalline structures of the anatase TNTs. The intensity of the peaks increased with increasing annealing temperature. The strong sharp peaks indicate the large quantities and higher degrees of crystallinity of anatase phase of the TNTs. CRS Large Area Scan (LAS) and Depth profiling (DP) were employed to evaluate the crystallinity and phase distribution of TNTs-FS thermally treated at different temperatures. CRS LAS in the XY direction of TNTs-FS revealed the presence of differently crystallized anatase phases of TiO2 with Raman vibrational modes of 159.38 cm-1 (Eg), 208.37 cm-1 (Eg), 399.67 cm-1 (B1g), 514.25 cm-1 (A1g) and 641.58 cm-1 (Eg) for the samples annealed at 350 °C. The effect of annealing temperature on TiO2 phase evolution was meticulously evaluated using CRS for TNTs-FS for the samples annealed at 350 °C, 450 °C, 550 °C and 650 °C. The FWHM was estimated from CRS and decreases with increasing annealing temperature resulting in increasing crystallinity. Increase in anatase FWHM and anatase peak intensity implies higher degree of crystallinity and increasing crystallite sizes were also confirmed by XRD. Growing of titanium dioxide on functional substrates one novel contribution towards the fabrication of efficient electrode materials for solar cell development. Our method of characterizing TNTs-FS from a large area scan along the surface of the samples and depth profiling along the TNTs tube walls using confocal Raman spectroscopy prove to be a pivotal step in the development of efficient photoelectrode materials of the solar devices. , Thesis (MSc) -- Faculty of Science and Agriculture, 2017
- Full Text:
- Date Issued: 2017-12
Knowledge sharing practices amongst librarians in selected federal universities in South-Western Nigeria
- Authors: Bolanle, Akanbi Hawwa
- Date: 2017-11
- Subjects: Knowledge management , Academic libraries
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10353/25289 , vital:64139
- Description: This study focused on Knowledge Sharing Practices Amongst Librarians in Selected Federal Universities in South-Western Nigerian. The southwest geopolitical zone chosen for this study is one of the largest geopolitical zones in Nigeria. The zone has six states with six Federal universities. Each of the states in south-west zone in Nigeria has one Federal University. The study was targeted at Librarians in each of the Federal Universities. These Librarians studied were from Obafemi Awolowo University (OAU) Ile Ife, Federal University of Technology (FUTA) Akure, University of Lagos (UNILAG) Akoka, Federal University of Oye Ekiti (FUOYE) Oye Ekiti, University of Ibadan (UI) Ibadan and Federal University of Agriculture Abeokuta (FUNAAB). The aforementioned universities are located in Osun State, Ondo State, Lagos State, Ekiti State, and Oyo State, respectively. Specifically, the objectives of this study were to determine the factors that affect the knowledge sharing practices amongst librarians in the south western Federal universities in Nigeria; to find out the perception of librarians on knowledge sharing in the Federal University libraries; to investigate the method of sharing knowledge and the effectiveness of such methods among academic librarians at the selected Universities in Nigeria; as well as to determine the extent to which librarians in Federal Universities encourage information exchange and the use of modern technologies. In order to achieve these, a multistage sampling technique was used. Purposive sampling technique was first used with the criteria that all the universities selected must be owned by Federal government; and only professional librarians in the respective university libraries participated. The Total enumerative technique was also used although not all professional librarians across the six federal universities were reached, owing to few limitations. However, 147 professional librarians across all six federal university libraries in south-western zone, Nigeria were randomly selected and eventually used for the purposes of this study. This study makes use of triangulation for data collection. In other words, the instruments used for all the data collected are Questionnaire, Interview and Focus Group Discussion. This was because the nature of data collected is a combination of qualitative and quantitative data. Questionnaires (147) were administered to librarians in all the federal universities with the aid of research assistants in each of the institution libraries. Descriptive and Inferential Statistics were used to analyse the data gathered with the aid of Statistical package for Social Sciences (SPSS) version 23. Subsequently, the Interview and Focus Group Discussion were organized after retrieving data gathered through questionnaires. Focus Group Discussion (FGD) was used to get some facts in line with the objectives of the study from librarians in the areas of study. This was done with the aid of a tape recorder, which was later transcribed and descriptively analyzed. Data gathered with the aid of interview and FGD were transcribed and interpreted. From all the instruments across the areas of study, it was found that the rate at which knowledge is shared through meetings and workshops is not encouraging as the findings showed that there was a very low response in this regard. The study concluded that there were several factors that affect knowledge sharing practices in the study site. Some of the key factors that influence knowledge sharing practices include: organizational structure, provision of incentives, Managerial practices, improved ICT, social relationship and training. This therefore suggests that organizational structure, provision of incentives, managerial practices, improved ICT, social relationship, training, trust, peer influence and perceived reciprocal benefit have a significant effect on knowledge sharing practices amongst librarians in South-western federal University libraries. It was found that there was a positive and significant effect of organizational structure on knowledge sharing practices amongst librarians. Results of the descriptive statistics on the perception of some librarians showed that librarians understood the concept of knowledge sharing as they agreed that knowledge possessed by an individual should be shared with another individual. In addition, on average, librarians supported the fact that knowledge sharing can bring innovation and creativity to library services. Although the findings were somehow consistent with previous studies, this study noted a number of contradictions and gaps that border on some of these factors. These are mode of sharing knowledge; particularly with respect to the availability of ICT facilities and their usage and the extent to which librarians in the study area share their knowledge which seems to be somehow not encouraging. Based on the findings, it was recommended that Organizational structures within each University library should be friendly and productive. Subsequently, No matter what, more is better than less. Librarians in all the six selected Southwestern university libraries should be motivated by giving them more incentives or rewards (both intrinsic and extrinsic rewards). In other words, there is a need for the management of the respective institutions to introduce additional incentives in order for their staff (librarians) to be fully motivated to increase their impetus to engage more in knowledge sharing practices. Despite the positive perception of librarians in the area of study, they still need to be motivated. , Thesis (PhD) -- Faculty of Social Sciences and Humanities, 2017
- Full Text:
- Date Issued: 2017-11
- Authors: Bolanle, Akanbi Hawwa
- Date: 2017-11
- Subjects: Knowledge management , Academic libraries
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10353/25289 , vital:64139
- Description: This study focused on Knowledge Sharing Practices Amongst Librarians in Selected Federal Universities in South-Western Nigerian. The southwest geopolitical zone chosen for this study is one of the largest geopolitical zones in Nigeria. The zone has six states with six Federal universities. Each of the states in south-west zone in Nigeria has one Federal University. The study was targeted at Librarians in each of the Federal Universities. These Librarians studied were from Obafemi Awolowo University (OAU) Ile Ife, Federal University of Technology (FUTA) Akure, University of Lagos (UNILAG) Akoka, Federal University of Oye Ekiti (FUOYE) Oye Ekiti, University of Ibadan (UI) Ibadan and Federal University of Agriculture Abeokuta (FUNAAB). The aforementioned universities are located in Osun State, Ondo State, Lagos State, Ekiti State, and Oyo State, respectively. Specifically, the objectives of this study were to determine the factors that affect the knowledge sharing practices amongst librarians in the south western Federal universities in Nigeria; to find out the perception of librarians on knowledge sharing in the Federal University libraries; to investigate the method of sharing knowledge and the effectiveness of such methods among academic librarians at the selected Universities in Nigeria; as well as to determine the extent to which librarians in Federal Universities encourage information exchange and the use of modern technologies. In order to achieve these, a multistage sampling technique was used. Purposive sampling technique was first used with the criteria that all the universities selected must be owned by Federal government; and only professional librarians in the respective university libraries participated. The Total enumerative technique was also used although not all professional librarians across the six federal universities were reached, owing to few limitations. However, 147 professional librarians across all six federal university libraries in south-western zone, Nigeria were randomly selected and eventually used for the purposes of this study. This study makes use of triangulation for data collection. In other words, the instruments used for all the data collected are Questionnaire, Interview and Focus Group Discussion. This was because the nature of data collected is a combination of qualitative and quantitative data. Questionnaires (147) were administered to librarians in all the federal universities with the aid of research assistants in each of the institution libraries. Descriptive and Inferential Statistics were used to analyse the data gathered with the aid of Statistical package for Social Sciences (SPSS) version 23. Subsequently, the Interview and Focus Group Discussion were organized after retrieving data gathered through questionnaires. Focus Group Discussion (FGD) was used to get some facts in line with the objectives of the study from librarians in the areas of study. This was done with the aid of a tape recorder, which was later transcribed and descriptively analyzed. Data gathered with the aid of interview and FGD were transcribed and interpreted. From all the instruments across the areas of study, it was found that the rate at which knowledge is shared through meetings and workshops is not encouraging as the findings showed that there was a very low response in this regard. The study concluded that there were several factors that affect knowledge sharing practices in the study site. Some of the key factors that influence knowledge sharing practices include: organizational structure, provision of incentives, Managerial practices, improved ICT, social relationship and training. This therefore suggests that organizational structure, provision of incentives, managerial practices, improved ICT, social relationship, training, trust, peer influence and perceived reciprocal benefit have a significant effect on knowledge sharing practices amongst librarians in South-western federal University libraries. It was found that there was a positive and significant effect of organizational structure on knowledge sharing practices amongst librarians. Results of the descriptive statistics on the perception of some librarians showed that librarians understood the concept of knowledge sharing as they agreed that knowledge possessed by an individual should be shared with another individual. In addition, on average, librarians supported the fact that knowledge sharing can bring innovation and creativity to library services. Although the findings were somehow consistent with previous studies, this study noted a number of contradictions and gaps that border on some of these factors. These are mode of sharing knowledge; particularly with respect to the availability of ICT facilities and their usage and the extent to which librarians in the study area share their knowledge which seems to be somehow not encouraging. Based on the findings, it was recommended that Organizational structures within each University library should be friendly and productive. Subsequently, No matter what, more is better than less. Librarians in all the six selected Southwestern university libraries should be motivated by giving them more incentives or rewards (both intrinsic and extrinsic rewards). In other words, there is a need for the management of the respective institutions to introduce additional incentives in order for their staff (librarians) to be fully motivated to increase their impetus to engage more in knowledge sharing practices. Despite the positive perception of librarians in the area of study, they still need to be motivated. , Thesis (PhD) -- Faculty of Social Sciences and Humanities, 2017
- Full Text:
- Date Issued: 2017-11
Perceptions Of School Based Support Teams About Providing Support To Foundation Phase Teachers In Two Butterworth Primary Schools, Eastern Cape
- Authors: Luningo, Mziwonke
- Date: 2017-11
- Subjects: School support teams
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/11260/6668 , vital:47202
- Description: The Policy on Inclusive Education acknowledges that all children can learn if they are given the necessary support. In order to achieve this goal, the Department of Education (DoE) introduced the establishment of School-Based Support Teams (SBSTs) whose main function is to support teaching and learning in schools. Nonetheless, there seems to be challenges on how to support learners experiencing barriers to learning among the members of the SBST. The aim of this study is to explore the perceptions of the SBSTs about providing support to the Foundation Phase (FP) teachers in two Butterworth Primary Schools in the Eastern Cape. This study used the qualitative mode of inquiry and a case study as a research design. Face-to face semi-structured interviews, observations and document analysis were used to collect the data from the SBSTs about their perceptions in providing support to the FP teachers. Data was analysed by identifying common themes. The findings revealed that the SBSTs do not have enough knowledge and skills on how to support the FP teachers. Some of the challenges they cited include inadequate training, lack of communication, overcrowding in classrooms, lack of support from the parents and from the Department of Education. In an attempt to alleviate the above raised challenges, a model has been proposed. , Thesis (D.Ed) -- Faculty of Education Sciences, 2020
- Full Text:
- Date Issued: 2017-11
- Authors: Luningo, Mziwonke
- Date: 2017-11
- Subjects: School support teams
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/11260/6668 , vital:47202
- Description: The Policy on Inclusive Education acknowledges that all children can learn if they are given the necessary support. In order to achieve this goal, the Department of Education (DoE) introduced the establishment of School-Based Support Teams (SBSTs) whose main function is to support teaching and learning in schools. Nonetheless, there seems to be challenges on how to support learners experiencing barriers to learning among the members of the SBST. The aim of this study is to explore the perceptions of the SBSTs about providing support to the Foundation Phase (FP) teachers in two Butterworth Primary Schools in the Eastern Cape. This study used the qualitative mode of inquiry and a case study as a research design. Face-to face semi-structured interviews, observations and document analysis were used to collect the data from the SBSTs about their perceptions in providing support to the FP teachers. Data was analysed by identifying common themes. The findings revealed that the SBSTs do not have enough knowledge and skills on how to support the FP teachers. Some of the challenges they cited include inadequate training, lack of communication, overcrowding in classrooms, lack of support from the parents and from the Department of Education. In an attempt to alleviate the above raised challenges, a model has been proposed. , Thesis (D.Ed) -- Faculty of Education Sciences, 2020
- Full Text:
- Date Issued: 2017-11
Perceptions of School Based Support Teams about Providing Support to Foundation Phase Teachers in Two Butterworth Primary Schools, Eastern Cape
- Authors: Luningo, Mziwonke
- Date: 2017-11
- Subjects: School Support Teams
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/11260/6653 , vital:47204
- Description: The Policy on Inclusive Education acknowledges that all children can learn if they are given the necessary support. In order to achieve this goal, the Department of Education (DoE) introduced the establishment of School-Based Support Teams (SBSTs) whose main function is to support teaching and learning in schools. Nonetheless, there seems to be challenges on how to support learners experiencing barriers to learning among the members of the SBST. The aim of this study is to explore the perceptions of the SBSTs about providing support to the Foundation Phase (FP) teachers in two Butterworth Primary Schools in the Eastern Cape. This study used the qualitative mode of inquiry and a case study as a research design. Face-to face semi-structured interviews, observations and document analysis were used to collect the data from the SBSTs about their perceptions in providing support to the FP teachers. Data was analysed by identifying common themes. The findings revealed that the SBSTs do not have enough knowledge and skills on how to support the FP teachers. Some of the challenges they cited include inadequate training, lack of communication, overcrowding in classrooms, lack of support from the parents and from the Department of Education. In an attempt to alleviate the above raised challenges, a model has been proposed. , Thesis (D.Ed) -- Faculty of Education Sciences, 2017
- Full Text:
- Date Issued: 2017-11
- Authors: Luningo, Mziwonke
- Date: 2017-11
- Subjects: School Support Teams
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/11260/6653 , vital:47204
- Description: The Policy on Inclusive Education acknowledges that all children can learn if they are given the necessary support. In order to achieve this goal, the Department of Education (DoE) introduced the establishment of School-Based Support Teams (SBSTs) whose main function is to support teaching and learning in schools. Nonetheless, there seems to be challenges on how to support learners experiencing barriers to learning among the members of the SBST. The aim of this study is to explore the perceptions of the SBSTs about providing support to the Foundation Phase (FP) teachers in two Butterworth Primary Schools in the Eastern Cape. This study used the qualitative mode of inquiry and a case study as a research design. Face-to face semi-structured interviews, observations and document analysis were used to collect the data from the SBSTs about their perceptions in providing support to the FP teachers. Data was analysed by identifying common themes. The findings revealed that the SBSTs do not have enough knowledge and skills on how to support the FP teachers. Some of the challenges they cited include inadequate training, lack of communication, overcrowding in classrooms, lack of support from the parents and from the Department of Education. In an attempt to alleviate the above raised challenges, a model has been proposed. , Thesis (D.Ed) -- Faculty of Education Sciences, 2017
- Full Text:
- Date Issued: 2017-11
Examining the reasons for the exclusion of pregnant learners from school through the school governing body pregnancy policy
- Bamidele, James Seidu https://orcid.org/0000-0001-6641-0385
- Authors: Bamidele, James Seidu https://orcid.org/0000-0001-6641-0385
- Date: 2017-07
- Subjects: School board members , Pregnant teenagers , Human rights
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/22979 , vital:53375
- Description: Discrimination is a serious violation of human rights and it is strongly condemned by various legal instruments in South Africa. The South African Constitution (1996), Promotion of Administration Justice Act (2000) and Promotion of Equality and Prevention of Unfair Discrimination Act (2000) forbade discrimination and exclusion of pregnant learners from school. In spite of these legislative frameworks, School Governing Body (SGB) continues to exclude pregnant learners from school. SGB claimed that pregnant learners are harmful to other female learners and is becoming a significant barrier to girls’ education. Research shows that learners’ pregnancy is predominant in rural areas, apparently poses a threat to female education (Annual School Survey Report, 2010). The purpose of this dissertation is to establish that SGB lacks power to do so; however, their resistance to the law by excluding the pregnant learners from school is in conflict with the South African Constitution. This dissertation investigated an alternative instrument of legal remedy to reduce the problem of learners’ pregnancy rather than exclusion. The theoretical framework of this study is informed by Public Policy Theory (Ijeoma, 2010). Literatures and scholarly works on education law (Oosthuizen, 2015) and articles on Learners’ pregnancy shall be reviewed (Morell, Bhana & Shefer, 2012). The study followed qualitative research method which utilizes a transformative research paradigm that provides a collective voice for the participants. The data is collected through focused interview and open-ended questions, and subsequently analysed to establish that SGB lacks power to exclude a pregnant learner from school. Finally, the study reveals an alternative instrument of legal remedy to reduce the alarming number of pregnant learners rather than exclusion. , Thesis (MEd) -- Faculty of Education, 2017
- Full Text:
- Date Issued: 2017-07
- Authors: Bamidele, James Seidu https://orcid.org/0000-0001-6641-0385
- Date: 2017-07
- Subjects: School board members , Pregnant teenagers , Human rights
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/22979 , vital:53375
- Description: Discrimination is a serious violation of human rights and it is strongly condemned by various legal instruments in South Africa. The South African Constitution (1996), Promotion of Administration Justice Act (2000) and Promotion of Equality and Prevention of Unfair Discrimination Act (2000) forbade discrimination and exclusion of pregnant learners from school. In spite of these legislative frameworks, School Governing Body (SGB) continues to exclude pregnant learners from school. SGB claimed that pregnant learners are harmful to other female learners and is becoming a significant barrier to girls’ education. Research shows that learners’ pregnancy is predominant in rural areas, apparently poses a threat to female education (Annual School Survey Report, 2010). The purpose of this dissertation is to establish that SGB lacks power to do so; however, their resistance to the law by excluding the pregnant learners from school is in conflict with the South African Constitution. This dissertation investigated an alternative instrument of legal remedy to reduce the problem of learners’ pregnancy rather than exclusion. The theoretical framework of this study is informed by Public Policy Theory (Ijeoma, 2010). Literatures and scholarly works on education law (Oosthuizen, 2015) and articles on Learners’ pregnancy shall be reviewed (Morell, Bhana & Shefer, 2012). The study followed qualitative research method which utilizes a transformative research paradigm that provides a collective voice for the participants. The data is collected through focused interview and open-ended questions, and subsequently analysed to establish that SGB lacks power to exclude a pregnant learner from school. Finally, the study reveals an alternative instrument of legal remedy to reduce the alarming number of pregnant learners rather than exclusion. , Thesis (MEd) -- Faculty of Education, 2017
- Full Text:
- Date Issued: 2017-07
The role of the liberation movements’ archives in shaping history writing in a post-apartheid South Africa
- Authors: Maamoe, Mosoabuli
- Date: 2017-07
- Subjects: Archives , Apartheid , National liberation movements--South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/23045 , vital:55287
- Description: This study offers a comprehensive examination of the Role of the Liberation Movements’ Archives in Shaping History Writing in a Post-Apartheid South Africa. It is based on the Liberation Archives housed at the National Heritage and Cultural Studies (NAHECS) at the University of Fort Hare, near the town of Alice in the Eastern Cape Province. A new narrative, grounded in the exploration and advantages of the use of these materials in their totality, given the new environment of research created under the new dispensation, has now become possible. The first chapter begins with an overview of the nature of archives in general and proceeds from there to consider the unique circumstances under which the different liberation movements of South Africa constructed their archives, and how these circumstances affected the nature of the materials preserved therein. One key point made here is that the liberation movement, as it spearheaded the struggle against apartheid, had already positioned itself as a “Government in Waiting,” convinced of the justness of its cause, and of the ultimate defeat of apartheid leading to he political seizure of power by the people. Hence, it created struggle materials seen as vehicles for the realisation and attainment of this objective. For this purpose, the appropriate housekeeping, viewing, consultation and access is absolutely relevant. The second chapter looks at the changing environment in which the repatriation of the struggle archives was implemented, and the decision to place them specifically at the University of Fort Hare and challenges. The third chapter narrates the difficulties encountered following the location of documents at Fort Hare, contestations, and contradictions between the stakeholders and the ultimate resolutions. The fourth and longest chapter goes to the heart of this thesis which dispel the myths created by the colonists and their historians intended to obscure the oppressed into embracing a historiography of South Africa that crossly flawed and distorted, silent and ignorant of reflecting early African societal developments which were evolving undisturbed at their own rate under socio-cultural and geographical conditions prior the advent of colonialism and the consequences. Therefore, based on these circumstances one can see that the installation of the new dispensation was not the end of the struggle, but the opening of a new chapter, the struggle against the conceptual legacy of apartheid and its vestiges. An evaluation of the consultation and exploitation of the archival collections comprises this subject in the last chapter of this study. Perusing them, one learns and realizes that the objective of the liberation movements was immense, to reconnect the marginalised of their once trampled and vilified history in order to inspire and empower them to reclaim their lost sense of belonging, identity, pride and to restore their humanity. This has been vindicated by the wide range of researchers and viewers from home and afar who have turned out to consult the archives in order to unpack the complexities of the South African history and that of the struggle. The information they contain serve as guides of addressing such complexities to arrest current transitional challenges, and offer solutions for some in articulating a need of building a new cohesive nation in a post-apartheid era. This is precisely what the liberation movement had in mind when it took a decision to gather together the struggle materials and have them repatriated for preservation and access purposes. It was not just generosity on its part, but also a display of the patriotic and passionate responsibility to the oppressed in particular and humanity in general to fathom and unpack the complexities of the South African historiography. , Thesis (PhD) -- Faculty of Social Science and Humanities,2021
- Full Text:
- Date Issued: 2017-07
- Authors: Maamoe, Mosoabuli
- Date: 2017-07
- Subjects: Archives , Apartheid , National liberation movements--South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/23045 , vital:55287
- Description: This study offers a comprehensive examination of the Role of the Liberation Movements’ Archives in Shaping History Writing in a Post-Apartheid South Africa. It is based on the Liberation Archives housed at the National Heritage and Cultural Studies (NAHECS) at the University of Fort Hare, near the town of Alice in the Eastern Cape Province. A new narrative, grounded in the exploration and advantages of the use of these materials in their totality, given the new environment of research created under the new dispensation, has now become possible. The first chapter begins with an overview of the nature of archives in general and proceeds from there to consider the unique circumstances under which the different liberation movements of South Africa constructed their archives, and how these circumstances affected the nature of the materials preserved therein. One key point made here is that the liberation movement, as it spearheaded the struggle against apartheid, had already positioned itself as a “Government in Waiting,” convinced of the justness of its cause, and of the ultimate defeat of apartheid leading to he political seizure of power by the people. Hence, it created struggle materials seen as vehicles for the realisation and attainment of this objective. For this purpose, the appropriate housekeeping, viewing, consultation and access is absolutely relevant. The second chapter looks at the changing environment in which the repatriation of the struggle archives was implemented, and the decision to place them specifically at the University of Fort Hare and challenges. The third chapter narrates the difficulties encountered following the location of documents at Fort Hare, contestations, and contradictions between the stakeholders and the ultimate resolutions. The fourth and longest chapter goes to the heart of this thesis which dispel the myths created by the colonists and their historians intended to obscure the oppressed into embracing a historiography of South Africa that crossly flawed and distorted, silent and ignorant of reflecting early African societal developments which were evolving undisturbed at their own rate under socio-cultural and geographical conditions prior the advent of colonialism and the consequences. Therefore, based on these circumstances one can see that the installation of the new dispensation was not the end of the struggle, but the opening of a new chapter, the struggle against the conceptual legacy of apartheid and its vestiges. An evaluation of the consultation and exploitation of the archival collections comprises this subject in the last chapter of this study. Perusing them, one learns and realizes that the objective of the liberation movements was immense, to reconnect the marginalised of their once trampled and vilified history in order to inspire and empower them to reclaim their lost sense of belonging, identity, pride and to restore their humanity. This has been vindicated by the wide range of researchers and viewers from home and afar who have turned out to consult the archives in order to unpack the complexities of the South African history and that of the struggle. The information they contain serve as guides of addressing such complexities to arrest current transitional challenges, and offer solutions for some in articulating a need of building a new cohesive nation in a post-apartheid era. This is precisely what the liberation movement had in mind when it took a decision to gather together the struggle materials and have them repatriated for preservation and access purposes. It was not just generosity on its part, but also a display of the patriotic and passionate responsibility to the oppressed in particular and humanity in general to fathom and unpack the complexities of the South African historiography. , Thesis (PhD) -- Faculty of Social Science and Humanities,2021
- Full Text:
- Date Issued: 2017-07
New Unity Movement Bulletin
- Date: 2017-05
- Subjects: Government, Resistance to -- South Africa , South Africa -- History -- 20th century , South Africa -- Politics and government
- Language: English
- Type: text , journal
- Identifier: http://hdl.handle.net/10948/32079 , vital:31949 , Bulk File 7
- Description: The Bulletin was the official newsletter of the New Unity Movement. It was published about twice a year and contained articles reflecting the organisation's views on resistance to the Apartheid government.
- Full Text: false
- Date Issued: 2017-05
- Date: 2017-05
- Subjects: Government, Resistance to -- South Africa , South Africa -- History -- 20th century , South Africa -- Politics and government
- Language: English
- Type: text , journal
- Identifier: http://hdl.handle.net/10948/32079 , vital:31949 , Bulk File 7
- Description: The Bulletin was the official newsletter of the New Unity Movement. It was published about twice a year and contained articles reflecting the organisation's views on resistance to the Apartheid government.
- Full Text: false
- Date Issued: 2017-05
A comparative study on Staff Retention in South Africa’s multinational banking corporations and micro-lenders
- Carolus, Chris Mario Periandros
- Authors: Carolus, Chris Mario Periandros
- Date: 2017-04
- Subjects: Employee retention -- South Africa , Employee motivation -- South Africa , Job satisfaction -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/66434 , vital:75319
- Description: The financial industry has changed rapidly over the past decade with competition being ferocious in the South African market. Traditionally most competition was among the four major banks, being ABSA, Nedbank, First National Bank and Standard Bank; however various small to medium micro-lenders, such as Capitec Bank, have grown more rapidly than the four major banks. These are the banks against which Multinational Corporations compete for products, services as well as employees. Staff employed in sales plays a critical role in any organisation and once that person leaves the organisation, productivity levels are set to be impacted along with margins on which banks are competing. It is thus of great importance for banks to pay close attention to staff retention in their respective organisations. Employees are viewed as the most important resource within any business, as firms are set to ensure a competitive advantage to remain profitable and cope with adversities that the global economy might present. The objective of this research was to establish whether the aspects of staff retention in Multinational Banking Corporations in South Africa differ from Micro- lenders locally. To ensure the objective was achieved, a literature review was conducted to understand the concepts that influence aspects of staff retention. Secondly, based on these aspects, a quantitative questionnaire was designed to obtain staff responses to the aspects of staff retention. The primary findings from the study indicate that the aspects of staff retention do indeed differ between Micro-lenders and Multinational Banking Corporations. Some of the main differences that were uncovered by the study occurred around transparency from leadership, lack of ability to develop talent and working conditions. Overall most respondents from Micro-lenders appear to be happier than respondents in Multinational Banking Corporations. The above factors are set to contribute significantly towards staff retention challenges for Multinational Banking Corporations, where employees are more disengaged, and that influences productivity negatively. , Thesis (MBA) -- Faculty of Business and Economic Sciences, Business School, 2017
- Full Text:
- Date Issued: 2017-04
- Authors: Carolus, Chris Mario Periandros
- Date: 2017-04
- Subjects: Employee retention -- South Africa , Employee motivation -- South Africa , Job satisfaction -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/66434 , vital:75319
- Description: The financial industry has changed rapidly over the past decade with competition being ferocious in the South African market. Traditionally most competition was among the four major banks, being ABSA, Nedbank, First National Bank and Standard Bank; however various small to medium micro-lenders, such as Capitec Bank, have grown more rapidly than the four major banks. These are the banks against which Multinational Corporations compete for products, services as well as employees. Staff employed in sales plays a critical role in any organisation and once that person leaves the organisation, productivity levels are set to be impacted along with margins on which banks are competing. It is thus of great importance for banks to pay close attention to staff retention in their respective organisations. Employees are viewed as the most important resource within any business, as firms are set to ensure a competitive advantage to remain profitable and cope with adversities that the global economy might present. The objective of this research was to establish whether the aspects of staff retention in Multinational Banking Corporations in South Africa differ from Micro- lenders locally. To ensure the objective was achieved, a literature review was conducted to understand the concepts that influence aspects of staff retention. Secondly, based on these aspects, a quantitative questionnaire was designed to obtain staff responses to the aspects of staff retention. The primary findings from the study indicate that the aspects of staff retention do indeed differ between Micro-lenders and Multinational Banking Corporations. Some of the main differences that were uncovered by the study occurred around transparency from leadership, lack of ability to develop talent and working conditions. Overall most respondents from Micro-lenders appear to be happier than respondents in Multinational Banking Corporations. The above factors are set to contribute significantly towards staff retention challenges for Multinational Banking Corporations, where employees are more disengaged, and that influences productivity negatively. , Thesis (MBA) -- Faculty of Business and Economic Sciences, Business School, 2017
- Full Text:
- Date Issued: 2017-04
Mediating teaching and learning in Foundation Phase Grade 3 Life Skills classrooms: role and use of learning and teaching support materials
- Authors: Nqabeni, Pelokazi
- Date: 2017-04
- Subjects: teaching strategies
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/11260/9436 , vital:73535
- Description: The study explored the role and use of learning and teaching support materials (LTSMs) to mediate teaching and learning in Life Skills Grade 3 classrooms of Dutywa District, in the province of the Eastern Cape, South Africa. It was prompted by a deep concern about the role and use of LTSMs to mediate teaching and learning in the Foundation Phase. While studies have been carried out on LTSMs in Foundation Phase, few studies have looked at the role and use of LTSMs to mediate teaching and learning in Life Skills Grade 3 classrooms. The study used a qualitative approach and is a multiple-case study of three purposively sampled schools from the rural areas. Teachers who participated in the study were Grade 3 teachers from the three schools. A pilot study was conducted in three schools with Foundation Phase, which were not used for the main study, for the purpose of validity and reliability. In this study, Cultural Historical Activity Theory (CHAT) was used as a framework to understand that actions are mediated by a complex network of socio-historical activities. I drew on the second generation of the activity theory, which has roots in Leontiev’s work on the Cultural Historical Activity Theory (CHAT), which provided both explanatory and analytical tools. I collected data using documents including journal entries, individual semi-structured interviews, and structured observations. The interviews were voice recorded with participant’s permission in order to present verbatim statements. In structured observations, I observed the role and use of LTSMs to mediate teaching and learning in Life Skills Grade 3 classrooms in the three selected schools. Content analysis guided the data analysis through themes derived from the subsidiary questions and coded for easy referencing. Data reporting took the form of thick description and verbatim quotations in line with the qualitative approach of the study. The study’s findings revealed non-availability of learning and teaching support materials in Life Skills subject. This suggests that intervention is needed by the Department of Education such as providing LTSMs which are essential in order to address the problem of not being used to mediate teaching and learning in classrooms. Language used in the role and use of learning and teaching support materials to mediate teaching and learning, lack of professional development, the effect of the non-examinable nature of Life Skills, and shortage and overcrowded classrooms were some of the aspects affecting the role and use of LTSMs to mediate teaching and learning in Life Skills Grade 3 classrooms. Based on the study findings, then I recommend that further research be conducted on strategies that could be employed to improve the role and use of LTSMs to mediate teaching and learning in Life Skills Grade 3 classrooms in a way that benefits learners. The Departmental officials including subject advisors, principals, teachers and learners should work together to improve the role and use of LTSMs to mediate teaching and learning in classrooms for quality education and to improve results in Foundation Phase. A model is proposed as the new knowledge for the existing literature on the role and use of LTSMs to mediate teaching and learning in classroom based on the theoretical framework and findings of this study. , Thesis (D.Ed) -- Faculty of Education Sciences, 2017
- Full Text:
- Date Issued: 2017-04
- Authors: Nqabeni, Pelokazi
- Date: 2017-04
- Subjects: teaching strategies
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/11260/9436 , vital:73535
- Description: The study explored the role and use of learning and teaching support materials (LTSMs) to mediate teaching and learning in Life Skills Grade 3 classrooms of Dutywa District, in the province of the Eastern Cape, South Africa. It was prompted by a deep concern about the role and use of LTSMs to mediate teaching and learning in the Foundation Phase. While studies have been carried out on LTSMs in Foundation Phase, few studies have looked at the role and use of LTSMs to mediate teaching and learning in Life Skills Grade 3 classrooms. The study used a qualitative approach and is a multiple-case study of three purposively sampled schools from the rural areas. Teachers who participated in the study were Grade 3 teachers from the three schools. A pilot study was conducted in three schools with Foundation Phase, which were not used for the main study, for the purpose of validity and reliability. In this study, Cultural Historical Activity Theory (CHAT) was used as a framework to understand that actions are mediated by a complex network of socio-historical activities. I drew on the second generation of the activity theory, which has roots in Leontiev’s work on the Cultural Historical Activity Theory (CHAT), which provided both explanatory and analytical tools. I collected data using documents including journal entries, individual semi-structured interviews, and structured observations. The interviews were voice recorded with participant’s permission in order to present verbatim statements. In structured observations, I observed the role and use of LTSMs to mediate teaching and learning in Life Skills Grade 3 classrooms in the three selected schools. Content analysis guided the data analysis through themes derived from the subsidiary questions and coded for easy referencing. Data reporting took the form of thick description and verbatim quotations in line with the qualitative approach of the study. The study’s findings revealed non-availability of learning and teaching support materials in Life Skills subject. This suggests that intervention is needed by the Department of Education such as providing LTSMs which are essential in order to address the problem of not being used to mediate teaching and learning in classrooms. Language used in the role and use of learning and teaching support materials to mediate teaching and learning, lack of professional development, the effect of the non-examinable nature of Life Skills, and shortage and overcrowded classrooms were some of the aspects affecting the role and use of LTSMs to mediate teaching and learning in Life Skills Grade 3 classrooms. Based on the study findings, then I recommend that further research be conducted on strategies that could be employed to improve the role and use of LTSMs to mediate teaching and learning in Life Skills Grade 3 classrooms in a way that benefits learners. The Departmental officials including subject advisors, principals, teachers and learners should work together to improve the role and use of LTSMs to mediate teaching and learning in classrooms for quality education and to improve results in Foundation Phase. A model is proposed as the new knowledge for the existing literature on the role and use of LTSMs to mediate teaching and learning in classroom based on the theoretical framework and findings of this study. , Thesis (D.Ed) -- Faculty of Education Sciences, 2017
- Full Text:
- Date Issued: 2017-04
Synthesis and biolgical screening of potential plasmodium falciparum DXR inhibitors
- Authors: Adeyemi, Christiana Modupe
- Date: 2017-04
- Subjects: Plasmodium falciparum , Enzyme inhibitors , Malaria , Antimalarials , Drug development , Malaria -- Chemotherapy , Isopentenoids -- Synthesis , Fosmidomycin , 1-Deoxy-D-xylulose 5-phosphate
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/61790 , vital:28060
- Description: The non-mevalonate isoprenoid pathway, also known as the 1-deoxy-D-xylulose-5- phosphate DXP pathway, is absent in humans, but present in the anopheles mosquito responsible for the transmission of malaria. DXP reductoisomerase - a key enzyme in the DXP pathway in Plasmodium falciparum (PfDXR) has been identified as a target for the design of novel anti-malarial drugs. Fosmidomycin and its acetyl analogue (FR900098) are known to be inhibitors of PfDXR and, in this study, synthetic variations of the fosmidomycin scaffold have led to four series of novel analogues. Particular attention has been centred on the introduction of various substituted benzyl groups in each of these series in order to occupy a recently discovered vacant pocket in the PfDXR active-site and thus enhance ligand-enzyme binding. In the process 160 ligands and precursors have been prepared, no less than 119 of them novel. Fistly, a series of C-benzylated phosphonate esters and phosphonic acids were synthesised, in which the fosmidomycin hydroxamate Mg2+- coordinating moiety was replaced by an amide funtionality and the number of methylene groups in the “hydrophobic patch” between the phosphonate and the hydroxamate moiety was decreased from two to one. Several approaches were explored for this series, the most successful involving reaction of 3- substituted anilines with a-bromo propanoic acid in the presence of the coupling agent 1,1'- carbonyldiimidazole (CDI), followed by Michaelis-Arbuzov phosphonation using triethyl phosphite. Reaction of the resulting chiral phosphonate esters with bromotrimethylsilane gave the corresponding phosphonic acids in good yields. In order to obviate chirality issues, a second series of potential “reverse” fosmidomycin analogues was synthesised by replacing the methylene group adjacent to the the phosphonate moiety with a nitrogen atom. Deprotonation, alkylation and phosphorylation of various amines gave diethyl #-benzylphosphoramidate ester intermediate. Aza-Michael addition of these intermediates, followed by hydrolysis gave the corresponding carboxylic acids which could be reacted with different hydroxylamine hydrochloride derivatives to afford the novel hydroxamic acid derivatives in good yields. Thirdly, a series of a novel #-benzylated phosphoramidate derivatives were prepared as aza- FR900098 analogues. Alkylation of different amines using bromoacetalde-hyde diethylacetal gave a series of N-benzyl-2,2-diethoxyethylamine compounds, which were then elaborated via a futher six steps to afford novel #-benzylated phosphoramidate derivatives. Finally, in order to ensure syn-orientation of the donor atoms in the Mg - coordinating group and, at the same time, introduce conformational constraints in the ligand, the hydrophobic patch and the hydroxamate moiety were replaced by cyclic systems. Several approaches towards the synthesis of such conformationally constrained phosphoramidate analogues from maleic anhydride led to the unexpected isolation of an unprecedented acyclic furfuryl compound, and 1H NMR and DFT-level theoretical studies have been initiated to explore the reaction sequence. A series of #-benzylated phosphoramidate derivatives containing dihydroxy aromatic rings (as the conformationally constrained groups) to replace the hydroxamate moiety, were successfully obtained in six steps from the starting material, 3,4-dihydroxylbenzaldehyde. While in vitro assays have been conducted on all of the synthesised compounds, and some of the ligands show promising anti-malarial inhibitory activity - most especially the conformationally constrained cyclic #-benzylated phosphoramidate series. Interestingly, a number of these compounds has also shown activity against T.brucei - the causative agent of sleeping sickness. In silico docking studies of selected compounds has revealed the capacity of some of the ligands to bind effectively in the PfDXR active-site with the newly introduced benzyl group occupying the adjacent vacant pocket. The physico-chemical properties of these ligands were also explored in order to predict the oral-bioavailability. Most of the ligands obeyed the Lipinski rule of 5, while QSAR methods have been used in an attempt to correlate structural variations and calculated molecular properties with the bioassay data. , Thesis (PhD) -- Faculty of Science, Chemistry, 2017
- Full Text:
- Date Issued: 2017-04
- Authors: Adeyemi, Christiana Modupe
- Date: 2017-04
- Subjects: Plasmodium falciparum , Enzyme inhibitors , Malaria , Antimalarials , Drug development , Malaria -- Chemotherapy , Isopentenoids -- Synthesis , Fosmidomycin , 1-Deoxy-D-xylulose 5-phosphate
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/61790 , vital:28060
- Description: The non-mevalonate isoprenoid pathway, also known as the 1-deoxy-D-xylulose-5- phosphate DXP pathway, is absent in humans, but present in the anopheles mosquito responsible for the transmission of malaria. DXP reductoisomerase - a key enzyme in the DXP pathway in Plasmodium falciparum (PfDXR) has been identified as a target for the design of novel anti-malarial drugs. Fosmidomycin and its acetyl analogue (FR900098) are known to be inhibitors of PfDXR and, in this study, synthetic variations of the fosmidomycin scaffold have led to four series of novel analogues. Particular attention has been centred on the introduction of various substituted benzyl groups in each of these series in order to occupy a recently discovered vacant pocket in the PfDXR active-site and thus enhance ligand-enzyme binding. In the process 160 ligands and precursors have been prepared, no less than 119 of them novel. Fistly, a series of C-benzylated phosphonate esters and phosphonic acids were synthesised, in which the fosmidomycin hydroxamate Mg2+- coordinating moiety was replaced by an amide funtionality and the number of methylene groups in the “hydrophobic patch” between the phosphonate and the hydroxamate moiety was decreased from two to one. Several approaches were explored for this series, the most successful involving reaction of 3- substituted anilines with a-bromo propanoic acid in the presence of the coupling agent 1,1'- carbonyldiimidazole (CDI), followed by Michaelis-Arbuzov phosphonation using triethyl phosphite. Reaction of the resulting chiral phosphonate esters with bromotrimethylsilane gave the corresponding phosphonic acids in good yields. In order to obviate chirality issues, a second series of potential “reverse” fosmidomycin analogues was synthesised by replacing the methylene group adjacent to the the phosphonate moiety with a nitrogen atom. Deprotonation, alkylation and phosphorylation of various amines gave diethyl #-benzylphosphoramidate ester intermediate. Aza-Michael addition of these intermediates, followed by hydrolysis gave the corresponding carboxylic acids which could be reacted with different hydroxylamine hydrochloride derivatives to afford the novel hydroxamic acid derivatives in good yields. Thirdly, a series of a novel #-benzylated phosphoramidate derivatives were prepared as aza- FR900098 analogues. Alkylation of different amines using bromoacetalde-hyde diethylacetal gave a series of N-benzyl-2,2-diethoxyethylamine compounds, which were then elaborated via a futher six steps to afford novel #-benzylated phosphoramidate derivatives. Finally, in order to ensure syn-orientation of the donor atoms in the Mg - coordinating group and, at the same time, introduce conformational constraints in the ligand, the hydrophobic patch and the hydroxamate moiety were replaced by cyclic systems. Several approaches towards the synthesis of such conformationally constrained phosphoramidate analogues from maleic anhydride led to the unexpected isolation of an unprecedented acyclic furfuryl compound, and 1H NMR and DFT-level theoretical studies have been initiated to explore the reaction sequence. A series of #-benzylated phosphoramidate derivatives containing dihydroxy aromatic rings (as the conformationally constrained groups) to replace the hydroxamate moiety, were successfully obtained in six steps from the starting material, 3,4-dihydroxylbenzaldehyde. While in vitro assays have been conducted on all of the synthesised compounds, and some of the ligands show promising anti-malarial inhibitory activity - most especially the conformationally constrained cyclic #-benzylated phosphoramidate series. Interestingly, a number of these compounds has also shown activity against T.brucei - the causative agent of sleeping sickness. In silico docking studies of selected compounds has revealed the capacity of some of the ligands to bind effectively in the PfDXR active-site with the newly introduced benzyl group occupying the adjacent vacant pocket. The physico-chemical properties of these ligands were also explored in order to predict the oral-bioavailability. Most of the ligands obeyed the Lipinski rule of 5, while QSAR methods have been used in an attempt to correlate structural variations and calculated molecular properties with the bioassay data. , Thesis (PhD) -- Faculty of Science, Chemistry, 2017
- Full Text:
- Date Issued: 2017-04
Vice-Chancellor's welcome address: 2017 Graduation Ceremonies
- Authors: Mabizela, Sizwe
- Date: 2017-04
- Language: English
- Type: Text
- Identifier: http://hdl.handle.net/10962/7560 , vital:21273
- Full Text:
- Authors: Mabizela, Sizwe
- Date: 2017-04
- Language: English
- Type: Text
- Identifier: http://hdl.handle.net/10962/7560 , vital:21273
- Full Text:
Species distribution and antifungal susceptibility patterns of Candida isolates from a public tertiary teaching hospital in the Eastern Cape Province, South Africa
- Mnge, P, Okeleye, B I, Vasaikar, S D, Apalata, T
- Authors: Mnge, P , Okeleye, B I , Vasaikar, S D , Apalata, T
- Date: 2017-03-14
- Subjects: Candida Candida species , Antifungal agents Antifungal susceptibility
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/6817 , vital:49389 , http://dx.doi.org/10.1590/1414-431X20175797
- Description: Candida species are the leading cause of invasive fungal infections, and over the past decade there has been an increased isolation of drug resistant Candida species. This study aimed to identify the species distribution of Candida isolates and to determine their unique antifungal susceptibility and resistance patterns. During a cross-sectional study, 209 Candida isolates (recovered from 206 clinical samples) were collected and their species distribution was determined using ChromAgar Candida. The Vitek-2 system (Biomerieux, South Africa) was used to determine minimum inhibitory concentrations (MICs) to azoles (fluconazole, voriconazole), echinocandins (caspofungin, micafungin), polyenes (amphotericin B) and flucytosine. Four species of Candida were isolated, of which C. albicans was the most frequent, isolated in 45.4 percent (95/209) of the isolates, followed by C. glabrata: 31.1 percent (65/209). The MICs of the different antifungal drugs varied amongst the species of Candida. From the 130 isolates tested for MICs, 90.77 percent (112/130) were susceptible to all antifungal drugs and 6.9 percent (9/130) of the isolates were multi-drug resistant. C. dubliniensis (n=2) isolates were susceptible to all the above mentioned antifungal drugs. There was no significant difference in species distribution amongst clinical specimens and between patients’ genders (P40.05). An increase in MIC values for fluconazole and flucytosine towards the resistance range was observed. To our knowledge, this is the first report on surveillance of Candida species distribution and antifungal susceptibility at a public tertiary teaching hospital in Eastern Cape, South Africa.
- Full Text:
- Date Issued: 2017-03-14
- Authors: Mnge, P , Okeleye, B I , Vasaikar, S D , Apalata, T
- Date: 2017-03-14
- Subjects: Candida Candida species , Antifungal agents Antifungal susceptibility
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/6817 , vital:49389 , http://dx.doi.org/10.1590/1414-431X20175797
- Description: Candida species are the leading cause of invasive fungal infections, and over the past decade there has been an increased isolation of drug resistant Candida species. This study aimed to identify the species distribution of Candida isolates and to determine their unique antifungal susceptibility and resistance patterns. During a cross-sectional study, 209 Candida isolates (recovered from 206 clinical samples) were collected and their species distribution was determined using ChromAgar Candida. The Vitek-2 system (Biomerieux, South Africa) was used to determine minimum inhibitory concentrations (MICs) to azoles (fluconazole, voriconazole), echinocandins (caspofungin, micafungin), polyenes (amphotericin B) and flucytosine. Four species of Candida were isolated, of which C. albicans was the most frequent, isolated in 45.4 percent (95/209) of the isolates, followed by C. glabrata: 31.1 percent (65/209). The MICs of the different antifungal drugs varied amongst the species of Candida. From the 130 isolates tested for MICs, 90.77 percent (112/130) were susceptible to all antifungal drugs and 6.9 percent (9/130) of the isolates were multi-drug resistant. C. dubliniensis (n=2) isolates were susceptible to all the above mentioned antifungal drugs. There was no significant difference in species distribution amongst clinical specimens and between patients’ genders (P40.05). An increase in MIC values for fluconazole and flucytosine towards the resistance range was observed. To our knowledge, this is the first report on surveillance of Candida species distribution and antifungal susceptibility at a public tertiary teaching hospital in Eastern Cape, South Africa.
- Full Text:
- Date Issued: 2017-03-14
Vice-Chancellor's Welcome address to New Students and Parents 2017
- Authors: Mabizela, Sizwe
- Date: 2017-02
- Language: English
- Type: Text
- Identifier: vital:21304 , http://hdl.handle.net/10962/7823
- Full Text:
- Authors: Mabizela, Sizwe
- Date: 2017-02
- Language: English
- Type: Text
- Identifier: vital:21304 , http://hdl.handle.net/10962/7823
- Full Text:
"A sociological investigation of the influence of regular school feeding scheme on learners' academic performance at Ngqele Primary School in Nkonkobe municipality, Eastern Cape"
- Authors: James, Ntombovuyo Gloria
- Date: 2017
- Subjects: School children--Health and hygiene Nutrition--South Africa--Eastern Cape School attendance--South Africa--Eastern Cape
- Language: English
- Type: Thesis , Masters , Sociology
- Identifier: http://hdl.handle.net/10353/11516 , vital:39079
- Description: This study sought to examine a sociological approach of the influence of regular provision of school feeding scheme on learners’ academic performance at Ngqele Primary School, Nkonkobe Municipality, Eastern Cape Province, South Africa. The study explored the views of teachers and parents pertaining to regular provision of school feeding scheme on learners’ academic performance. In addition, the study examined the impact of regular provision of school feeding scheme on school attendance and the sustainability of the regular provision of school feeding scheme. The study utilized both qualitative and quantitative research methods in the form of in-depth interviews, and a survey method. The process was made possible through the use of purposive sampling and cluster sampling to generate the targeted participants of the study. The findings of the study have shown that the school feeding scheme has got an impact on learner’s academic performance due to the fact that learners are able to listen and pay attention to the teacher if they are fed, the SFS has a positive impact on learners’ attendance and high enrolment. However, the study has also shown that, despite the positive impact of the school feeding Scheme, there were some challenges that also impacted negatively on learners, the school and the implementation of the programme. Such challenges include irregular supply of food, food shortages and poor quality of food.
- Full Text:
- Date Issued: 2017
- Authors: James, Ntombovuyo Gloria
- Date: 2017
- Subjects: School children--Health and hygiene Nutrition--South Africa--Eastern Cape School attendance--South Africa--Eastern Cape
- Language: English
- Type: Thesis , Masters , Sociology
- Identifier: http://hdl.handle.net/10353/11516 , vital:39079
- Description: This study sought to examine a sociological approach of the influence of regular provision of school feeding scheme on learners’ academic performance at Ngqele Primary School, Nkonkobe Municipality, Eastern Cape Province, South Africa. The study explored the views of teachers and parents pertaining to regular provision of school feeding scheme on learners’ academic performance. In addition, the study examined the impact of regular provision of school feeding scheme on school attendance and the sustainability of the regular provision of school feeding scheme. The study utilized both qualitative and quantitative research methods in the form of in-depth interviews, and a survey method. The process was made possible through the use of purposive sampling and cluster sampling to generate the targeted participants of the study. The findings of the study have shown that the school feeding scheme has got an impact on learner’s academic performance due to the fact that learners are able to listen and pay attention to the teacher if they are fed, the SFS has a positive impact on learners’ attendance and high enrolment. However, the study has also shown that, despite the positive impact of the school feeding Scheme, there were some challenges that also impacted negatively on learners, the school and the implementation of the programme. Such challenges include irregular supply of food, food shortages and poor quality of food.
- Full Text:
- Date Issued: 2017
"The man can use that power", "she got courage" and "inimba": discursive resources in counsellors' talk of intimate partner violence: implications for practice
- Fleischack, Anne, Macleod, Catriona I, Böhmke, Werner
- Authors: Fleischack, Anne , Macleod, Catriona I , Böhmke, Werner
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67498 , vital:29103 , http://dx.doi.org/10.15270/52-2-550
- Description: Publisher version , Given the high rate of intimate partner violence (IPV), understanding how counsellors talk about IPV and their interventions is important. The authors conducted narrative interviews with eight counsellors from non-governmental organisations (NGOs) working with IPV. Using narrative-discursive methodology, this qualitative study paid attention to the discursive resources that the participants drew upon. Two broad clusters of discursive resources and one contradictory (‘nurturing femininity’) discourse emerged. The first cluster engenders a sense of helplessness in the face of overwhelming power relations; the second enables the counsellors to foresee positive outcomes for their counselling. Implications for counselling include emphasising enabling discourses, highlighting multiplicities of gender, and wider-scale interventions.
- Full Text:
- Date Issued: 2017
- Authors: Fleischack, Anne , Macleod, Catriona I , Böhmke, Werner
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67498 , vital:29103 , http://dx.doi.org/10.15270/52-2-550
- Description: Publisher version , Given the high rate of intimate partner violence (IPV), understanding how counsellors talk about IPV and their interventions is important. The authors conducted narrative interviews with eight counsellors from non-governmental organisations (NGOs) working with IPV. Using narrative-discursive methodology, this qualitative study paid attention to the discursive resources that the participants drew upon. Two broad clusters of discursive resources and one contradictory (‘nurturing femininity’) discourse emerged. The first cluster engenders a sense of helplessness in the face of overwhelming power relations; the second enables the counsellors to foresee positive outcomes for their counselling. Implications for counselling include emphasising enabling discourses, highlighting multiplicities of gender, and wider-scale interventions.
- Full Text:
- Date Issued: 2017
'Committed, motivated and joyful?'Job satisfaction and organisational commitment of managers at a South African public utility:
- Authors: Snowball, Jeanette D
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/70495 , vital:29667 , https://doi.org/10.1080/09548963.2017.1380706
- Description: The cultural and creative industries (CCIs) have been hailed as offering great potential to create jobs and to be socially inclusive. Since artistic success is defined by individual talent, or merit, the CCIs should be one sector that is especially open to, and appreciative of, social diversity in terms of race, class, cultural group and gender. However, as expected, recent studies in both the UK and the US have revealed that employment in the CCIs is heavily dominated by the middle classes, and is not as diverse in terms of other characteristics. Since the advent of democracy in South Africa in 1994, transformation of firm ownership, previously dominated by white people, to include more black, coloured and Indian/Asian-origin South Africans, has been an important part of achieving greater economic equality and social cohesion, as well as being more representative of the cultures of the majority of the population. Using data from a survey of 2400 CCIs firms in South Africa, this paper examines the extent to which the CCIs in South Africa have transformed in terms of ownership and employment. Comparisons are also made across the six UNESCO [(2009). Framework for cultural statistics. UNESCO Institute for Statistics. Retrieved from http://www.uis.unesco.org/culture/Pages/framework-cultural-statistics.aspx] “Cultural Domains” in terms of ownership, average monthly turnover and the number of full-time, part-time and contract employees. Results show some diversity in the industry, but significant differences between the Domains. Statistical analysis demonstrates that CCI funding policy in South Africa is sensitive to advancing the transformation agenda in that more transformed firms were shown to be more likely to have received some form of government grant as part of their income.
- Full Text:
- Date Issued: 2017
- Authors: Snowball, Jeanette D
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/70495 , vital:29667 , https://doi.org/10.1080/09548963.2017.1380706
- Description: The cultural and creative industries (CCIs) have been hailed as offering great potential to create jobs and to be socially inclusive. Since artistic success is defined by individual talent, or merit, the CCIs should be one sector that is especially open to, and appreciative of, social diversity in terms of race, class, cultural group and gender. However, as expected, recent studies in both the UK and the US have revealed that employment in the CCIs is heavily dominated by the middle classes, and is not as diverse in terms of other characteristics. Since the advent of democracy in South Africa in 1994, transformation of firm ownership, previously dominated by white people, to include more black, coloured and Indian/Asian-origin South Africans, has been an important part of achieving greater economic equality and social cohesion, as well as being more representative of the cultures of the majority of the population. Using data from a survey of 2400 CCIs firms in South Africa, this paper examines the extent to which the CCIs in South Africa have transformed in terms of ownership and employment. Comparisons are also made across the six UNESCO [(2009). Framework for cultural statistics. UNESCO Institute for Statistics. Retrieved from http://www.uis.unesco.org/culture/Pages/framework-cultural-statistics.aspx] “Cultural Domains” in terms of ownership, average monthly turnover and the number of full-time, part-time and contract employees. Results show some diversity in the industry, but significant differences between the Domains. Statistical analysis demonstrates that CCI funding policy in South Africa is sensitive to advancing the transformation agenda in that more transformed firms were shown to be more likely to have received some form of government grant as part of their income.
- Full Text:
- Date Issued: 2017
'n Ondersoek na die uitbeelding van Khoisan-karakters deur wit Afrikaanse prosateurs: 1994-2014
- Authors: December, Peter
- Date: 2017
- Subjects: Khoikhoi (African people) -- South Africa -- History Khoikhoi (African people) -- Race identity -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/22070 , vital:29819
- Description: This dissertation offers a literary-thematic investigation based on a postcolonial approach to the representation of the Khoisan and their descendants. I restricted my scope to selected Afrikaans novels at the centre of critical attention between between 1994 and 2014. Earlier novels in this period under discussion are Dolf van Niekerk’s Koms van die hyreën (1994), Willem Kotze’s Tsats van die Kalahari (1994), Die spoorsnyer (1994), Olifantjagters (1997) and Gif (2001) by Piet van Rooyen, plus Karel Schoeman’s Verkenning (1996). Later texts in the focus are Duiwelskloof (1998) and Bidsprinkaan (2005) by André P. Brink, Dalene Matthee’s Pieternella van die Kaap (2000), Eben Venter’s Santa Gamka (2009) and most recently, the Hertzog prize winner of 2015, Buys by Willem Anker (2014). Themes central to South African literature will form the focus of the research, namely intercultural interaction between the first inhabitants of South Africa and missionaries, the question of land ownership, the language motif, and the role of religion (indigenous versus Western belief systems). Attention will also be on more specific issues such as the nature of the relationship between the Khoisan and the colonisers, the characterization of the Khoisan by the selected white authors, as well as other contemporary debates. The secondary objective of the study is to review the historical presence of the Khoisan and their descendants as reflected through the fictional lense of these authors writing over the last two decades, since democratization of the regime in 1994. My focus is particularly on the substantial cultural contribution of the Khoi and the San, as reflected through their representation in fictional works. The question will be posed whether the portrayal of Khoisan characters in novels after 1994 is different from the portrayal in fiction before 1994? My hypothesis is that in the fictional representation one finds a move towards restoration of their human dignity, yet the fact remains that all the authors are white. A different study of fictional works by coloured writers (whose numbers as Afrikaans authors grew substantially after 1994), investigating their representation of the descendants of the Khoi and the San, would in all probability yield radically different results, as the white authors imagine the characters and their consciousness from outside the community and the racial group, whereas the coloured writers belong to the community and the group that they portray.
- Full Text:
- Date Issued: 2017
- Authors: December, Peter
- Date: 2017
- Subjects: Khoikhoi (African people) -- South Africa -- History Khoikhoi (African people) -- Race identity -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/22070 , vital:29819
- Description: This dissertation offers a literary-thematic investigation based on a postcolonial approach to the representation of the Khoisan and their descendants. I restricted my scope to selected Afrikaans novels at the centre of critical attention between between 1994 and 2014. Earlier novels in this period under discussion are Dolf van Niekerk’s Koms van die hyreën (1994), Willem Kotze’s Tsats van die Kalahari (1994), Die spoorsnyer (1994), Olifantjagters (1997) and Gif (2001) by Piet van Rooyen, plus Karel Schoeman’s Verkenning (1996). Later texts in the focus are Duiwelskloof (1998) and Bidsprinkaan (2005) by André P. Brink, Dalene Matthee’s Pieternella van die Kaap (2000), Eben Venter’s Santa Gamka (2009) and most recently, the Hertzog prize winner of 2015, Buys by Willem Anker (2014). Themes central to South African literature will form the focus of the research, namely intercultural interaction between the first inhabitants of South Africa and missionaries, the question of land ownership, the language motif, and the role of religion (indigenous versus Western belief systems). Attention will also be on more specific issues such as the nature of the relationship between the Khoisan and the colonisers, the characterization of the Khoisan by the selected white authors, as well as other contemporary debates. The secondary objective of the study is to review the historical presence of the Khoisan and their descendants as reflected through the fictional lense of these authors writing over the last two decades, since democratization of the regime in 1994. My focus is particularly on the substantial cultural contribution of the Khoi and the San, as reflected through their representation in fictional works. The question will be posed whether the portrayal of Khoisan characters in novels after 1994 is different from the portrayal in fiction before 1994? My hypothesis is that in the fictional representation one finds a move towards restoration of their human dignity, yet the fact remains that all the authors are white. A different study of fictional works by coloured writers (whose numbers as Afrikaans authors grew substantially after 1994), investigating their representation of the descendants of the Khoi and the San, would in all probability yield radically different results, as the white authors imagine the characters and their consciousness from outside the community and the racial group, whereas the coloured writers belong to the community and the group that they portray.
- Full Text:
- Date Issued: 2017
'She travels alone and unattended’: the visit to the Eastern Cape of the botanical artist, Marianne North
- Authors: Beard, Margot
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147759 , vital:38668 , https://doi.org/10.1080/00043389.2007.11877077
- Description: The visit of the botanical artist, Marianne North, to South Africa during 1882 to 1883, although frequently referred to, has not received much close attention; nor has her account of the visit, in her ‘Recollections of a happy’ life, been set against the actual conditions she would have encountered. This paper attempts to flesh out at least part of that visit, specifically the weeks she spent in the Eastern Cape Colony and, more particularly, her visits to Port Elizabeth, Grahamstown and Port Alfred. What were these three centres like at the time? Who were the people she mentions? Where did she stay? How do her observations tally with other accounts of the period?.
- Full Text:
- Date Issued: 2017
- Authors: Beard, Margot
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147759 , vital:38668 , https://doi.org/10.1080/00043389.2007.11877077
- Description: The visit of the botanical artist, Marianne North, to South Africa during 1882 to 1883, although frequently referred to, has not received much close attention; nor has her account of the visit, in her ‘Recollections of a happy’ life, been set against the actual conditions she would have encountered. This paper attempts to flesh out at least part of that visit, specifically the weeks she spent in the Eastern Cape Colony and, more particularly, her visits to Port Elizabeth, Grahamstown and Port Alfred. What were these three centres like at the time? Who were the people she mentions? Where did she stay? How do her observations tally with other accounts of the period?.
- Full Text:
- Date Issued: 2017
1H NMR-based kinetic and theoretical studies of the simultaneous formation of two discrete rotameric systems of a novel difenchyl sulfite ester
- Singh, Alicia, Kaye, Perry T, Lobb, Kevin A
- Authors: Singh, Alicia , Kaye, Perry T , Lobb, Kevin A
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447925 , vital:74684 , xlink:href="https://doi.org/10.1016/j.tet.2017.10.059"
- Description: Attempted repetition of a reported synthesis of fenchene from fenchol has afforded, in high overall yield, a mixture shown by spectroscopic and elemental analysis to comprise a pair of discrete rotameric systems of a novel 2-endo-2′-endo-difenchyl sulfite ester. The kinetics of the formation of these dimeric rotameric systems (I and II) has been explored experimentally, using 1H NMR spectroscopic analysis, and theoretically at molecular and quantum mechanical levels. Construction of a theoretical model has permitted calculation of rate constants for each of the steps, while modelling of the transition state complexes corresponding to the rate-determining steps for the formation of the rotameric systems I and II has revealed their independent access to further sets of interconverting rotamers.
- Full Text:
- Date Issued: 2017
- Authors: Singh, Alicia , Kaye, Perry T , Lobb, Kevin A
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447925 , vital:74684 , xlink:href="https://doi.org/10.1016/j.tet.2017.10.059"
- Description: Attempted repetition of a reported synthesis of fenchene from fenchol has afforded, in high overall yield, a mixture shown by spectroscopic and elemental analysis to comprise a pair of discrete rotameric systems of a novel 2-endo-2′-endo-difenchyl sulfite ester. The kinetics of the formation of these dimeric rotameric systems (I and II) has been explored experimentally, using 1H NMR spectroscopic analysis, and theoretically at molecular and quantum mechanical levels. Construction of a theoretical model has permitted calculation of rate constants for each of the steps, while modelling of the transition state complexes corresponding to the rate-determining steps for the formation of the rotameric systems I and II has revealed their independent access to further sets of interconverting rotamers.
- Full Text:
- Date Issued: 2017
4-Bis (4-aminophenoxy) phenoxy derivitized phthalocyanine conjugated to metallic nanoparticles
- Nwaji, Njemuwa, Mack, John, Nyokong, Tebello
- Authors: Nwaji, Njemuwa , Mack, John , Nyokong, Tebello
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188965 , vital:44802 , xlink:href="https://doi.org/10.1039/C7NJ02718D"
- Description: In this study, the photophysical, nonlinear absorption and nonlinear optical limiting properties of 4-(2,4-bis(4-aminophenoxy)phenoxy) phthalocyinato zinc(II) phthalocyanine (6) conjugated to metallic nanoparticles have been investigated using open aperture Z-scan techniques using 532 nm nanosecond pulses. The nonlinear optical response demonstrated that the studied complex and the nanoconjugates exhibit higher excited state absorption cross-section compared to ground state absorption. Enhanced optical limiting performance was observed when complex 6 was conjugated to nanoparticles with 6CB-AuNPs (CB = covalent bond) showing the highest optical limiting threshold of 0.36 J cm−2.
- Full Text:
- Date Issued: 2017
- Authors: Nwaji, Njemuwa , Mack, John , Nyokong, Tebello
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188965 , vital:44802 , xlink:href="https://doi.org/10.1039/C7NJ02718D"
- Description: In this study, the photophysical, nonlinear absorption and nonlinear optical limiting properties of 4-(2,4-bis(4-aminophenoxy)phenoxy) phthalocyinato zinc(II) phthalocyanine (6) conjugated to metallic nanoparticles have been investigated using open aperture Z-scan techniques using 532 nm nanosecond pulses. The nonlinear optical response demonstrated that the studied complex and the nanoconjugates exhibit higher excited state absorption cross-section compared to ground state absorption. Enhanced optical limiting performance was observed when complex 6 was conjugated to nanoparticles with 6CB-AuNPs (CB = covalent bond) showing the highest optical limiting threshold of 0.36 J cm−2.
- Full Text:
- Date Issued: 2017