Effects of gold nanoparticle shape on the aggregation and fluorescence behaviour of water soluble zinc phthalocyanines
- D'Souza, Sarah, Moeno, Sharon, Antunes, Edith M, Nyokong, Tebello
- Authors: D'Souza, Sarah , Moeno, Sharon , Antunes, Edith M , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/232500 , vital:49997 , xlink:href="https://doi.org/10.1039/C3NJ00146F"
- Description: The absorption and fluorescence response as well as the fluorescence quantum yields and lifetimes of sulfonated phthalocyanines and alkyl carboxylic acid substituted zinc phthalocyanines in the presence of differently shaped water soluble gold nanoparticles were studied. The respective phthalocyanines are known to be highly aggregated in water, which is reported to markedly reduce the excited state lifetimes. This paper shows that in the presence of star shaped gold nanoparticles, the degree of phthalocyanine aggregation in water is greatly reduced, but the aggregation status of the phthalocyanines does not change for spherical Au nanoparticles. Since gold nanoparticles have already proven to be useful in numerous nanomedicinal and nanomedical applications, the disaggregation of phthalocyanines is an added advantage.
- Full Text:
- Date Issued: 2013
- Authors: D'Souza, Sarah , Moeno, Sharon , Antunes, Edith M , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/232500 , vital:49997 , xlink:href="https://doi.org/10.1039/C3NJ00146F"
- Description: The absorption and fluorescence response as well as the fluorescence quantum yields and lifetimes of sulfonated phthalocyanines and alkyl carboxylic acid substituted zinc phthalocyanines in the presence of differently shaped water soluble gold nanoparticles were studied. The respective phthalocyanines are known to be highly aggregated in water, which is reported to markedly reduce the excited state lifetimes. This paper shows that in the presence of star shaped gold nanoparticles, the degree of phthalocyanine aggregation in water is greatly reduced, but the aggregation status of the phthalocyanines does not change for spherical Au nanoparticles. Since gold nanoparticles have already proven to be useful in numerous nanomedicinal and nanomedical applications, the disaggregation of phthalocyanines is an added advantage.
- Full Text:
- Date Issued: 2013
Electrochemical impedimetric immunosensor for the detection of measles-specific IgG antibodies after measles infections
- Mashazi, Philani N, Tetyana, Phumlani, Vilakazi, Sibulelo, Nyokong, Tebello
- Authors: Mashazi, Philani N , Tetyana, Phumlani , Vilakazi, Sibulelo , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241677 , vital:50960 , xlink:href="https://doi.org/10.1016/j.bios.2013.04.028"
- Description: The detection of measles-specific primary antibodies (IgG) using electrochemical impedimetric immunosensors is reported. The optimum conditions for electrode saturation were reached after 40 min for 1 μg ml−1 antibody concentrations. Surface roughness using AFM increased with each immobilization or antigen-antibody reaction step clearly confirming the surface modification and recognition between antigen and antibody. The human serum (HS) and new-born calf serum (NCS) spiked with antigen-specific antibody were studied to mimic the real sample analysis. The HS and NCS sera containing antibodies due to measles exhibited correlation between the increasing antibody serum concentrations and the charge-transfer resistance (electrochemically measured). This work clearly showed the potential use of impedance as the preferred electrochemical method for detecting measles-antibodies in label-free manner.
- Full Text:
- Date Issued: 2013
- Authors: Mashazi, Philani N , Tetyana, Phumlani , Vilakazi, Sibulelo , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241677 , vital:50960 , xlink:href="https://doi.org/10.1016/j.bios.2013.04.028"
- Description: The detection of measles-specific primary antibodies (IgG) using electrochemical impedimetric immunosensors is reported. The optimum conditions for electrode saturation were reached after 40 min for 1 μg ml−1 antibody concentrations. Surface roughness using AFM increased with each immobilization or antigen-antibody reaction step clearly confirming the surface modification and recognition between antigen and antibody. The human serum (HS) and new-born calf serum (NCS) spiked with antigen-specific antibody were studied to mimic the real sample analysis. The HS and NCS sera containing antibodies due to measles exhibited correlation between the increasing antibody serum concentrations and the charge-transfer resistance (electrochemically measured). This work clearly showed the potential use of impedance as the preferred electrochemical method for detecting measles-antibodies in label-free manner.
- Full Text:
- Date Issued: 2013
Electrospun fibers functionalized with phthalocyanine-gold nanoparticle conjugates for photocatalytic applications
- Tombe, Sekai, Antunes, Edith M, Nyokong, Tebello
- Authors: Tombe, Sekai , Antunes, Edith M , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193769 , vital:45394 , xlink:href="https://doi.org/10.1016/j.molcata.2013.01.033"
- Description: The heterogeneous photocatalytic activity of Zn(II) phthalocyanine-gold nanoparticle conjugates immobilized on electrospun polystyrene fibers was investigated using 4-chlorophenol and Orange G as model pollutants. The phthalocyanine-gold nanoparticle conjugates were synthesized via a ligand exchange reaction and characterized using spectroscopic and microscopic techniques. The interaction between the gold nanoparticles and phthalocyanines did not restrict the formation of excited singlet states, triplet states and hence the formation of singlet oxygen required for photocatalysis. The conjugates showed significantly higher singlet oxygen quantum yields and enhanced photocatalytic activity compared to the phthalocyanines. It was concluded that hybrid electrospun fibers provide great potential as active photocatalysts for oxidizing organic pollutants using singlet oxygen as an oxidant.
- Full Text:
- Date Issued: 2013
- Authors: Tombe, Sekai , Antunes, Edith M , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193769 , vital:45394 , xlink:href="https://doi.org/10.1016/j.molcata.2013.01.033"
- Description: The heterogeneous photocatalytic activity of Zn(II) phthalocyanine-gold nanoparticle conjugates immobilized on electrospun polystyrene fibers was investigated using 4-chlorophenol and Orange G as model pollutants. The phthalocyanine-gold nanoparticle conjugates were synthesized via a ligand exchange reaction and characterized using spectroscopic and microscopic techniques. The interaction between the gold nanoparticles and phthalocyanines did not restrict the formation of excited singlet states, triplet states and hence the formation of singlet oxygen required for photocatalysis. The conjugates showed significantly higher singlet oxygen quantum yields and enhanced photocatalytic activity compared to the phthalocyanines. It was concluded that hybrid electrospun fibers provide great potential as active photocatalysts for oxidizing organic pollutants using singlet oxygen as an oxidant.
- Full Text:
- Date Issued: 2013
Engineering Education Research for educational change: the possibilities of critical realism for conceptualising causal mechanicsms in education
- Case, Jennifer, Blackie, Margaret A
- Authors: Case, Jennifer , Blackie, Margaret A
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426637 , vital:72374 , xlink:href="https://doi.org/10.1016/j.biocontrol.2013.07.023"
- Description: Engineering Education Research (EER) grew in prominence from the late 1990s as purposes for this field were espoused in relation to the necessity of change for engineering education in the newly globalising world. Arguments centred on overall challenges with recruitment to engineering, specifically in relation to historically underrepresented populations, as well as with the forms of education (both in terms of quality of teaching and relevance of curricula) offered to students, and the needs of employers as reflected in newly-emerged global accreditation systems. In a field that is at least partly directed towards educational change, there is a need to understand how change typically happens in education systems. This article first draws on findings from the sociology of education to show that causality in relation to educational change is complex. It then turns to the philosophy of critical realism for a way of thinking about change that can inform EER, and concludes by outlining how this might change the research questions that drive the field, and how these might be approached.
- Full Text:
- Date Issued: 2013
- Authors: Case, Jennifer , Blackie, Margaret A
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426637 , vital:72374 , xlink:href="https://doi.org/10.1016/j.biocontrol.2013.07.023"
- Description: Engineering Education Research (EER) grew in prominence from the late 1990s as purposes for this field were espoused in relation to the necessity of change for engineering education in the newly globalising world. Arguments centred on overall challenges with recruitment to engineering, specifically in relation to historically underrepresented populations, as well as with the forms of education (both in terms of quality of teaching and relevance of curricula) offered to students, and the needs of employers as reflected in newly-emerged global accreditation systems. In a field that is at least partly directed towards educational change, there is a need to understand how change typically happens in education systems. This article first draws on findings from the sociology of education to show that causality in relation to educational change is complex. It then turns to the philosophy of critical realism for a way of thinking about change that can inform EER, and concludes by outlining how this might change the research questions that drive the field, and how these might be approached.
- Full Text:
- Date Issued: 2013
Environmental ethics as processes of open-ended, pluralistic, deliberative enquiry
- Authors: Olvitt, Lausanne L
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/437309 , vital:73368 , ISBN 9780203813331 , https://www.taylorfrancis.com/chapters/edit/10.4324/9780203813331-15/environmental-ethics-processes-open-ended-pluralistic-deliberative-enquiry-lausanne-olvitt
- Description: By the very nature of their work, environmental education re-searchers must engage with environmental philosophy and questions of values and ethics. But this terrain, despite being resourced with an apparently endless supply of typologies, an-thologies, and handbooks, can remain a vast and daunting philosophical sea—at least in my experience as a newcomer to the field, and possibly for many other scholars and re-searchers. This essay makes no claim to altering that and in-stead optimistically pursues Ball’s (2001, p. 89) suggestion that “there is much to be learned about, and from, the philosophical life-forms inhabiting these thickets and swamps.” My intention here is to review a relatively small but growing cluster of work in environmental ethics that proposes that:“Ethical positions are always open for discussion, re-examination, and revi-sion”(Jickling, 2004, p. 16) and are thus, by their very nature, open-ended, relational processes. My starting point in writing this essay is as an educator-researcher-environmentalist trying to explore what the field of environmental ethics has to offer in response to the question:“As educators, how can we learn and do more with others in the face of an unprecedented socioeco-logical crisis?”
- Full Text:
- Date Issued: 2013
- Authors: Olvitt, Lausanne L
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/437309 , vital:73368 , ISBN 9780203813331 , https://www.taylorfrancis.com/chapters/edit/10.4324/9780203813331-15/environmental-ethics-processes-open-ended-pluralistic-deliberative-enquiry-lausanne-olvitt
- Description: By the very nature of their work, environmental education re-searchers must engage with environmental philosophy and questions of values and ethics. But this terrain, despite being resourced with an apparently endless supply of typologies, an-thologies, and handbooks, can remain a vast and daunting philosophical sea—at least in my experience as a newcomer to the field, and possibly for many other scholars and re-searchers. This essay makes no claim to altering that and in-stead optimistically pursues Ball’s (2001, p. 89) suggestion that “there is much to be learned about, and from, the philosophical life-forms inhabiting these thickets and swamps.” My intention here is to review a relatively small but growing cluster of work in environmental ethics that proposes that:“Ethical positions are always open for discussion, re-examination, and revi-sion”(Jickling, 2004, p. 16) and are thus, by their very nature, open-ended, relational processes. My starting point in writing this essay is as an educator-researcher-environmentalist trying to explore what the field of environmental ethics has to offer in response to the question:“As educators, how can we learn and do more with others in the face of an unprecedented socioeco-logical crisis?”
- Full Text:
- Date Issued: 2013
Epidemic transmission of intestinal schistosomiasis in the seasonal part of the Okavango Delta, Botswana:
- Appleton, C C, Ellery, William F N, Byskov, Jens, Mogkweetsinyana, S S
- Authors: Appleton, C C , Ellery, William F N , Byskov, Jens , Mogkweetsinyana, S S
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144364 , vital:38339 , DOI: 10.1179/136485908X311867
- Description: A well documented epidemic of human intestinal schistosomiasis caused by Schistosoma mansoni occurred at Maun in the seasonal part of the Okavango Delta, Botswana, building from very few cases in the 1950s and early 1960s to a peak prevalence of greater than80% in the 1980s. A retrospective analysis was performed on all available records of the prevalence of S. mansoni in the Maun area and the corresponding flow records of the Thamalakane River. These revealed a statistically significant correlation between prevalence and flow, but only when a lag period was introduced. The correlation was greatest with a lag period of 5–6 years between the rise and fall of discharge and the rise and fall of transmission. Since the hydrological events in the delta follow a cyclical pattern, another epidemic around 2020 appears likely.
- Full Text:
- Date Issued: 2013
- Authors: Appleton, C C , Ellery, William F N , Byskov, Jens , Mogkweetsinyana, S S
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144364 , vital:38339 , DOI: 10.1179/136485908X311867
- Description: A well documented epidemic of human intestinal schistosomiasis caused by Schistosoma mansoni occurred at Maun in the seasonal part of the Okavango Delta, Botswana, building from very few cases in the 1950s and early 1960s to a peak prevalence of greater than80% in the 1980s. A retrospective analysis was performed on all available records of the prevalence of S. mansoni in the Maun area and the corresponding flow records of the Thamalakane River. These revealed a statistically significant correlation between prevalence and flow, but only when a lag period was introduced. The correlation was greatest with a lag period of 5–6 years between the rise and fall of discharge and the rise and fall of transmission. Since the hydrological events in the delta follow a cyclical pattern, another epidemic around 2020 appears likely.
- Full Text:
- Date Issued: 2013
Explaining the endurance of poverty and inequality : social policy and the social division of welfare in the South African health system
- Authors: Du Plessis, Ulandi
- Date: 2013
- Subjects: Health system , Private health , Public health , Poor , Subsidies , Profit motive , Quality , Efficiency , Public health -- Finance -- Research -- South Africa , Medical care -- Research -- South Africa , Poverty -- Research -- South Africa , Equality -- Research -- South Africa , South Africa -- Social conditions
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2755 , http://hdl.handle.net/10962/d1002002
- Description: This thesis examines the structure and flow of public funding between the public and private sectors in the South African health system and the consequences thereof for the achievement of equity. The conceptual framework used to undertake the analysis derives from Richard Titmuss’ core theoretical framework, the Social Division of Welfare. The application of the Social Division of Welfare applied to the South African health care context demonstrates how state resources end up benefitting the non-poor and, as a result, reproduce inequality. Those who access public institutions such as public health care are assumed to be ‘dependent’ on the state, whilst those who access private health facilities claim to be ‘independent’ of the state. However, this thesis shows that these assumptions are flawed. Access to the formal labour market, and subsequently the paying of taxes, authorises one to access state subsidies not available to those who do not. The application of the Social Division of Welfare shows that tax-paying private health care patients benefit considerably from state resources. This thesis argues that due to cost escalation in the private health sector, a consequence of the commodification of health care, these private health care ‘consumers’ as well as the private health industry in general are dependent upon state resources. This thesis analyses the role played by the profit motive present in the private health industry and the consequences for equity, quality, access and efficiency in health care provision
- Full Text:
- Date Issued: 2013
- Authors: Du Plessis, Ulandi
- Date: 2013
- Subjects: Health system , Private health , Public health , Poor , Subsidies , Profit motive , Quality , Efficiency , Public health -- Finance -- Research -- South Africa , Medical care -- Research -- South Africa , Poverty -- Research -- South Africa , Equality -- Research -- South Africa , South Africa -- Social conditions
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2755 , http://hdl.handle.net/10962/d1002002
- Description: This thesis examines the structure and flow of public funding between the public and private sectors in the South African health system and the consequences thereof for the achievement of equity. The conceptual framework used to undertake the analysis derives from Richard Titmuss’ core theoretical framework, the Social Division of Welfare. The application of the Social Division of Welfare applied to the South African health care context demonstrates how state resources end up benefitting the non-poor and, as a result, reproduce inequality. Those who access public institutions such as public health care are assumed to be ‘dependent’ on the state, whilst those who access private health facilities claim to be ‘independent’ of the state. However, this thesis shows that these assumptions are flawed. Access to the formal labour market, and subsequently the paying of taxes, authorises one to access state subsidies not available to those who do not. The application of the Social Division of Welfare shows that tax-paying private health care patients benefit considerably from state resources. This thesis argues that due to cost escalation in the private health sector, a consequence of the commodification of health care, these private health care ‘consumers’ as well as the private health industry in general are dependent upon state resources. This thesis analyses the role played by the profit motive present in the private health industry and the consequences for equity, quality, access and efficiency in health care provision
- Full Text:
- Date Issued: 2013
Exploring a systems approach to mainstreaming sustainability in universities: A case study of Rhodes University in South Africa
- Togo, Muchaiteyi, Lotz-Sisitka, Heila
- Authors: Togo, Muchaiteyi , Lotz-Sisitka, Heila
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182857 , vital:43886 , xlink:href="https://doi.org/10.1080/13504622.2012.749974"
- Description: This paper explores the use of systems theory to inform the mainstreaming of sustainability in a university’s functions as it responds to sustainable development challenges in its local context. Offering a case study of Rhodes University, the paper shows how the use of systems models and concepts, underpinned by a critical realist ontology and an understanding of morphogenetic change processes, have the potential to enable universities to mobilise their operations to respond to local sustainability challenges. In this instance, the success of such an approach is shown to depend on commitments from the university community and the availability of enabling inputs, such as financial and human resources. The paper concludes with reflections and recommendations to inform further development of a newly emerging systems approach in sustainability mainstreaming at Rhodes University, and other institutions pursuing similar approaches and goals.
- Full Text:
- Date Issued: 2013
- Authors: Togo, Muchaiteyi , Lotz-Sisitka, Heila
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182857 , vital:43886 , xlink:href="https://doi.org/10.1080/13504622.2012.749974"
- Description: This paper explores the use of systems theory to inform the mainstreaming of sustainability in a university’s functions as it responds to sustainable development challenges in its local context. Offering a case study of Rhodes University, the paper shows how the use of systems models and concepts, underpinned by a critical realist ontology and an understanding of morphogenetic change processes, have the potential to enable universities to mobilise their operations to respond to local sustainability challenges. In this instance, the success of such an approach is shown to depend on commitments from the university community and the availability of enabling inputs, such as financial and human resources. The paper concludes with reflections and recommendations to inform further development of a newly emerging systems approach in sustainability mainstreaming at Rhodes University, and other institutions pursuing similar approaches and goals.
- Full Text:
- Date Issued: 2013
Exploring options in reforming South African land ownership: opportunities for sharing land, labour and expertise
- Dlamini, Thula S, Verschoor, Aart-Jan, Fraser, Gavin C G
- Authors: Dlamini, Thula S , Verschoor, Aart-Jan , Fraser, Gavin C G
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69331 , vital:29500 , https://doi.org/10.1080/03031853.2013.770951
- Description: In many developing countries, land ownership remains a subject of contention. In South Africa, notwithstanding the strides that have been made to foster equitable land ownership, land reform policies have been unsuccessful in delivering land to the poor majority. Due to the nature of agriculture as a source of food production and national security, and the lack of farming skills and related competencies’ equilibrium, programmes intended to deliver land to black people have been inadequate in their reach. Whereas policy has emphasised the urgency of solving equity issues in land ownership, equally challenging has been finding the right set of programmes to achieve this without triggering a perennial land ownership squabble. After 18 years of democracy, a need remains to find a balance between continuity in food production and equitable redistribution of land in South African agriculture. In this paper, we argue that it is possible to achieve equitable and fair redistribution of land without inhibiting agricultural production, through land sharing. We show that sharing land could help fast-track the development of a farming skills and related competencies’ equilibrium between black and white farmers. The paper further demonstrates that the gains in land sharing far outweigh other programmes of land reform that have been used and suggested thus far.
- Full Text: false
- Date Issued: 2013
- Authors: Dlamini, Thula S , Verschoor, Aart-Jan , Fraser, Gavin C G
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69331 , vital:29500 , https://doi.org/10.1080/03031853.2013.770951
- Description: In many developing countries, land ownership remains a subject of contention. In South Africa, notwithstanding the strides that have been made to foster equitable land ownership, land reform policies have been unsuccessful in delivering land to the poor majority. Due to the nature of agriculture as a source of food production and national security, and the lack of farming skills and related competencies’ equilibrium, programmes intended to deliver land to black people have been inadequate in their reach. Whereas policy has emphasised the urgency of solving equity issues in land ownership, equally challenging has been finding the right set of programmes to achieve this without triggering a perennial land ownership squabble. After 18 years of democracy, a need remains to find a balance between continuity in food production and equitable redistribution of land in South African agriculture. In this paper, we argue that it is possible to achieve equitable and fair redistribution of land without inhibiting agricultural production, through land sharing. We show that sharing land could help fast-track the development of a farming skills and related competencies’ equilibrium between black and white farmers. The paper further demonstrates that the gains in land sharing far outweigh other programmes of land reform that have been used and suggested thus far.
- Full Text: false
- Date Issued: 2013
Exploring the correlation between language medium and academic achievement: a comparative study of the language of learning and teaching (LoLT) and mathematics results in the 2010 Grade 12 National Senior Certificate examinations in the Eastern Cape
- Mbude-Shale, Beryl Ntombizanele
- Authors: Mbude-Shale, Beryl Ntombizanele
- Date: 2013
- Subjects: Academic achievement -- Research -- South Africa -- Eastern Cape Language and education -- Research -- South Africa -- Eastern Cape Language policy -- South Africa -- Eastern Cape Mathematics -- Study and teaching (Elementary) -- South Africa -- Eastern Cape Education, Secondary -- South Africa -- Eastern Cape Matric Learners Language planning Mathematics Policies Academic performance Mother-tongue
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:3559 , http://hdl.handle.net/10962/d1001863
- Description: In 2009, of the 68,129 learners who wrote Matric, only 34,731 learners passed. In 2010, there was an increase in the provincial pass rate causing much excitement across the board. The reality was that of the 64,090 learners who wrote, only 37,345 learners passed. In 2010, a result below 50% was recorded for Mathematics and Physical Science nationally (DBE; 2011). Despite efforts by the Education Department to support MSTE; establishing Mathematics and Science schools, NGOs and HEIs giving extra Mathematics and Science support to students and teachers, the offering of Saturday classes and incubation camps, we still get minimal return on investment. This thesis analyses these results against the backdrop of language planning theory, particularly language-in-education policies, pre and post-apartheid. The correlation between language medium and academic performance in language (LoLT) and Mathematics of Grade 12 learners is explored. Worldwide the issue of low achievement in Mathematics by ESL students is of great concern (Cuevas, 1984). The 2004 Systemic Evaluation sample of learners was in Grade 6 then; in 2010 they wrote Grade 12. The purpose of the systemic evaluation was to provide an insight into the levels of learner performance in Maths, Natural Science and LoLT in Grade 6 (IPSER, 2006). A major finding of the IPSER was that language was an important factor related to learner achievement. A major disparity was observed in this research, that although the Eastern Cape performed below the national average in the three subjects evaluated, the learners for whom LoLT was the same as their home language obtained scores that were significantly higher than those whose home language was different from the LoLT. The provincial average for Mathematics was 23.40% compared to the national average of 27.80%. For LoLT the province scored 30.16 against the national score of 38.03%. Of interest in this study is a juxtaposition of the Matric results of this same group of learners in 2010 and see whether issues that came up then are still significant in mitigating achievement in Mathematics and Language (LoLT). Some research studies have been conducted in South Africa (Adler, 1998; Setati, 1996-2002; Moloi, 2006) identifying the vital role language plays in learning Mathematics, especially for English L2 learners. Building on research and findings of academics such as the late Alexander, Ramani, Joseph, Hendricks, Heugh, Dalvit, Webb and Murray, this thesis suggests that a mother-tongue-based-bilingual approach to education should be adopted as a matter of urgency
- Full Text:
- Date Issued: 2013
- Authors: Mbude-Shale, Beryl Ntombizanele
- Date: 2013
- Subjects: Academic achievement -- Research -- South Africa -- Eastern Cape Language and education -- Research -- South Africa -- Eastern Cape Language policy -- South Africa -- Eastern Cape Mathematics -- Study and teaching (Elementary) -- South Africa -- Eastern Cape Education, Secondary -- South Africa -- Eastern Cape Matric Learners Language planning Mathematics Policies Academic performance Mother-tongue
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:3559 , http://hdl.handle.net/10962/d1001863
- Description: In 2009, of the 68,129 learners who wrote Matric, only 34,731 learners passed. In 2010, there was an increase in the provincial pass rate causing much excitement across the board. The reality was that of the 64,090 learners who wrote, only 37,345 learners passed. In 2010, a result below 50% was recorded for Mathematics and Physical Science nationally (DBE; 2011). Despite efforts by the Education Department to support MSTE; establishing Mathematics and Science schools, NGOs and HEIs giving extra Mathematics and Science support to students and teachers, the offering of Saturday classes and incubation camps, we still get minimal return on investment. This thesis analyses these results against the backdrop of language planning theory, particularly language-in-education policies, pre and post-apartheid. The correlation between language medium and academic performance in language (LoLT) and Mathematics of Grade 12 learners is explored. Worldwide the issue of low achievement in Mathematics by ESL students is of great concern (Cuevas, 1984). The 2004 Systemic Evaluation sample of learners was in Grade 6 then; in 2010 they wrote Grade 12. The purpose of the systemic evaluation was to provide an insight into the levels of learner performance in Maths, Natural Science and LoLT in Grade 6 (IPSER, 2006). A major finding of the IPSER was that language was an important factor related to learner achievement. A major disparity was observed in this research, that although the Eastern Cape performed below the national average in the three subjects evaluated, the learners for whom LoLT was the same as their home language obtained scores that were significantly higher than those whose home language was different from the LoLT. The provincial average for Mathematics was 23.40% compared to the national average of 27.80%. For LoLT the province scored 30.16 against the national score of 38.03%. Of interest in this study is a juxtaposition of the Matric results of this same group of learners in 2010 and see whether issues that came up then are still significant in mitigating achievement in Mathematics and Language (LoLT). Some research studies have been conducted in South Africa (Adler, 1998; Setati, 1996-2002; Moloi, 2006) identifying the vital role language plays in learning Mathematics, especially for English L2 learners. Building on research and findings of academics such as the late Alexander, Ramani, Joseph, Hendricks, Heugh, Dalvit, Webb and Murray, this thesis suggests that a mother-tongue-based-bilingual approach to education should be adopted as a matter of urgency
- Full Text:
- Date Issued: 2013
Exploring the influence of spirituality on students' well-being
- Authors: Magula, Nokuzola Princess
- Date: 2013
- Subjects: Sprituality , Well-being , Students , Christians , Rhodes University , College students -- Religious life -- South Africa -- Eastern Cape , Christian college students -- Religious life -- South Africa -- Eastern Cape , Universities and colleges -- Religion -- Research , Well-being -- Religious aspects , Spirituality -- Research
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2918 , http://hdl.handle.net/10962/d1002083
- Description: This study was aimed at exploring the impact of spirituality on the well-being of students at Rhodes University in South Africa. The study was conducted within a qualitative research paradigm deploying an interpretive phenomenological analysis strategy for data analysis. The study involved a sample of four female Honours students who were all active Christians. The selected students were interviewed to elicit their experiences of spirituality and how this related to their everyday lives. The study used semi-structured interviews in order to get as much information as possible from the small sample of research participants. Data generated in this study was processed, presented and interpreted inductively and hermeneutically in order to identify emerging superordinate themes. This study found that spirituality was experienced as having a positive impact on well-being by all the four students. The study revealed that belief and faith in God amongst the students resulted in enhanced and positive experiences of hope, optimism and compassion which provided the students with a deeper sense of meaning of life and a source of direction in difficult times. The study further showed that participants experienced spirituality as a regulatory mechanism shaping their lifestyles and behaviours. Participants viewed their spirituality and religiosity as a source of social support helping them to cope with distressful situations. The findings of this study are consistent with the findings of previous studies done in the field of psychology and spirituality. The fact that this study has shown that spirituality and religion has a positive impact on student’s well-being may mean that University administrators and psychologists may find the study interesting and valuable
- Full Text:
- Date Issued: 2013
- Authors: Magula, Nokuzola Princess
- Date: 2013
- Subjects: Sprituality , Well-being , Students , Christians , Rhodes University , College students -- Religious life -- South Africa -- Eastern Cape , Christian college students -- Religious life -- South Africa -- Eastern Cape , Universities and colleges -- Religion -- Research , Well-being -- Religious aspects , Spirituality -- Research
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2918 , http://hdl.handle.net/10962/d1002083
- Description: This study was aimed at exploring the impact of spirituality on the well-being of students at Rhodes University in South Africa. The study was conducted within a qualitative research paradigm deploying an interpretive phenomenological analysis strategy for data analysis. The study involved a sample of four female Honours students who were all active Christians. The selected students were interviewed to elicit their experiences of spirituality and how this related to their everyday lives. The study used semi-structured interviews in order to get as much information as possible from the small sample of research participants. Data generated in this study was processed, presented and interpreted inductively and hermeneutically in order to identify emerging superordinate themes. This study found that spirituality was experienced as having a positive impact on well-being by all the four students. The study revealed that belief and faith in God amongst the students resulted in enhanced and positive experiences of hope, optimism and compassion which provided the students with a deeper sense of meaning of life and a source of direction in difficult times. The study further showed that participants experienced spirituality as a regulatory mechanism shaping their lifestyles and behaviours. Participants viewed their spirituality and religiosity as a source of social support helping them to cope with distressful situations. The findings of this study are consistent with the findings of previous studies done in the field of psychology and spirituality. The fact that this study has shown that spirituality and religion has a positive impact on student’s well-being may mean that University administrators and psychologists may find the study interesting and valuable
- Full Text:
- Date Issued: 2013
Exploring the possibility of an Ubuntu-based political philosophy
- Authors: Furman, Katherine Elizabeth
- Date: 2013
- Subjects: Ubuntu , Political philosophy , Ethical theories , Law , South Africa , Ubuntu (Philosophy) -- Research -- South Africa , Political science -- Philosophy -- Research , Philosophy, African -- Research , Social values -- Research South Africa , Ethics -- Research -- South Africa
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2756 , http://hdl.handle.net/10962/d1002003
- Description: It is typically said that there are two questions that political philosophy seeks to address: ‘who gets what?’ and ‘who decides on who gets what?’ South Africa, along with much of the rest of the world, has answered the second question badly and currently ranks as one of the world’s most unequal societies. Counter-intuitively, South Africa maintains a social-political order that (re)produces this inequality along with great enthusiasm for ubuntu, an African ethic that at a minimum requires that we treat each other humanely. However, due to the view that ubuntu has been co-opted in support of South Africa’s unjust system, ubuntu has largely been ignored by radical thinkers. The aim of this thesis is therefore to explore the possibility of an ubuntu-based political philosophy, with the core assumption that political philosophy is rooted in ethical theory. Three tasks are therefore undertaken in this thesis. Firstly, ubuntu is articulated as an ethic. Secondly, it is compared to similar Western ethical theories in order to determine if there are distinguishing characteristics that make ubuntu a more appropriate founding ethic for South African political philosophy. Finally, whether ubuntu can find real-world applicability will be assessed by looking at the way ubuntu has been used in the law
- Full Text:
- Date Issued: 2013
- Authors: Furman, Katherine Elizabeth
- Date: 2013
- Subjects: Ubuntu , Political philosophy , Ethical theories , Law , South Africa , Ubuntu (Philosophy) -- Research -- South Africa , Political science -- Philosophy -- Research , Philosophy, African -- Research , Social values -- Research South Africa , Ethics -- Research -- South Africa
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2756 , http://hdl.handle.net/10962/d1002003
- Description: It is typically said that there are two questions that political philosophy seeks to address: ‘who gets what?’ and ‘who decides on who gets what?’ South Africa, along with much of the rest of the world, has answered the second question badly and currently ranks as one of the world’s most unequal societies. Counter-intuitively, South Africa maintains a social-political order that (re)produces this inequality along with great enthusiasm for ubuntu, an African ethic that at a minimum requires that we treat each other humanely. However, due to the view that ubuntu has been co-opted in support of South Africa’s unjust system, ubuntu has largely been ignored by radical thinkers. The aim of this thesis is therefore to explore the possibility of an ubuntu-based political philosophy, with the core assumption that political philosophy is rooted in ethical theory. Three tasks are therefore undertaken in this thesis. Firstly, ubuntu is articulated as an ethic. Secondly, it is compared to similar Western ethical theories in order to determine if there are distinguishing characteristics that make ubuntu a more appropriate founding ethic for South African political philosophy. Finally, whether ubuntu can find real-world applicability will be assessed by looking at the way ubuntu has been used in the law
- Full Text:
- Date Issued: 2013
Factors which Influence English Language Pass Rate at Matric Level in the Engcobo District of The Eastern Cape of South Africa
- Songwaxa, Nokuthula Patience
- Authors: Songwaxa, Nokuthula Patience
- Date: 2013
- Language: English
- Type: Masters theses , text
- Identifier: http://hdl.handle.net/11260/3517 , vital:43622
- Description: This study investigates the management of English teaching to improve matriculation pass-rate in selected schools in the Engcobo District of the Eastern Cape of South Africa. The study has been circuits of the Engcobo district. Questionnaires were administered over a group of matriculants, English second language teachers and 8 school principals with a variety of questions and interviews on the causes of this failure problem. Based on the study it has been reared through collect data that some teachers have not been workshopped in the current curriculum (NCS) and this somehow affects the learners. Learners from rural areas have a problem in understanding English language. Lack of educational facilities like libraries also have a negative impact in learner’s progress. Learners who came from Junior Secondary Schools to High schools are not ready and this gives High School teachers a big task to mould them to be ready for matric. It is recommended that parental involvement is vital in their children’s education so as to see their progress and to develop the teacher-parent locomotives learners need to be engaged in Educational activities like debates, public speaking, conducting so as to improve their communication skills. Educators should give more writing and reading exercises to learners so as to minimize the number of learners who are unable to write in Matric. , Thesis (MMED) -- Faculty of Educational Sciences, 2013
- Full Text:
- Date Issued: 2013
- Authors: Songwaxa, Nokuthula Patience
- Date: 2013
- Language: English
- Type: Masters theses , text
- Identifier: http://hdl.handle.net/11260/3517 , vital:43622
- Description: This study investigates the management of English teaching to improve matriculation pass-rate in selected schools in the Engcobo District of the Eastern Cape of South Africa. The study has been circuits of the Engcobo district. Questionnaires were administered over a group of matriculants, English second language teachers and 8 school principals with a variety of questions and interviews on the causes of this failure problem. Based on the study it has been reared through collect data that some teachers have not been workshopped in the current curriculum (NCS) and this somehow affects the learners. Learners from rural areas have a problem in understanding English language. Lack of educational facilities like libraries also have a negative impact in learner’s progress. Learners who came from Junior Secondary Schools to High schools are not ready and this gives High School teachers a big task to mould them to be ready for matric. It is recommended that parental involvement is vital in their children’s education so as to see their progress and to develop the teacher-parent locomotives learners need to be engaged in Educational activities like debates, public speaking, conducting so as to improve their communication skills. Educators should give more writing and reading exercises to learners so as to minimize the number of learners who are unable to write in Matric. , Thesis (MMED) -- Faculty of Educational Sciences, 2013
- Full Text:
- Date Issued: 2013
Farewell to Lawrence Schlemmer: initiator of quality-of-life studies in South Africa
- Authors: Moller, Valerie
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67175 , vital:29055 , https://doi.org/10.1007/s11205-011-9965-8
- Description: publisher version , Professor Lawrence Schlemmer, affectionately known as Lawrie, was the father of South Africa’s quality-of-life studies and social indicators movement. He died on 26 October 2011 at the age of 75 after a short illness. In 1978, Lawrence marched into my office at the Centre for Applied Social Sciences, University of Natal, brandishing two books. We need to do some work on quality of life in South Africa, he announced, before handing me the volumes. At the time, South Africa’s leaders assumed that smiling black faces meant that South Africans were happy with their lot in life under apartheid. Our surveys were to prove otherwise. That weekend was spent reading cover to cover the classic works by Frank Andrews, Angus Campbell and their colleagues. The next week we pored over lists of concerns voiced by South Africans which we later put to test in the field. In 1982, we submitted our findings by ‘slug’ post to the editor of Social Indicators Research. We received a letter by return mail from Alex Michalos to say he would publish our paper and we should not be too disappointed with our regression results!
- Full Text: false
- Date Issued: 2013
- Authors: Moller, Valerie
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67175 , vital:29055 , https://doi.org/10.1007/s11205-011-9965-8
- Description: publisher version , Professor Lawrence Schlemmer, affectionately known as Lawrie, was the father of South Africa’s quality-of-life studies and social indicators movement. He died on 26 October 2011 at the age of 75 after a short illness. In 1978, Lawrence marched into my office at the Centre for Applied Social Sciences, University of Natal, brandishing two books. We need to do some work on quality of life in South Africa, he announced, before handing me the volumes. At the time, South Africa’s leaders assumed that smiling black faces meant that South Africans were happy with their lot in life under apartheid. Our surveys were to prove otherwise. That weekend was spent reading cover to cover the classic works by Frank Andrews, Angus Campbell and their colleagues. The next week we pored over lists of concerns voiced by South Africans which we later put to test in the field. In 1982, we submitted our findings by ‘slug’ post to the editor of Social Indicators Research. We received a letter by return mail from Alex Michalos to say he would publish our paper and we should not be too disappointed with our regression results!
- Full Text: false
- Date Issued: 2013
Farmers’ perceptions of the impact of legislation on farm workers’ wages and working conditions: an Eastern Cape case study
- Roberts, Tamaryn, Antrobus, Geoffrey G
- Authors: Roberts, Tamaryn , Antrobus, Geoffrey G
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142911 , vital:38175 , DOI: 10.1080/03031853.2013.778464
- Description: The status of South African farm workers has changed significantly over the past five decades. Using data from three major surveys conducted between 1957 and 2008, an Eastern Cape district was used as a case study to assess farmers’ perceptions of the changes that had occurred, particularly as a result of legislation. Considering the changes, the impacts on the farm labour market and wage and non-wage working conditions are analysed. The legislation focused on includes the Extension of Security of Tenure Act 62 (ESTA) of 1997, the Basic Conditions of Employment Act 75 (BCEA) of 1997 and minimum wage legislation. Farmers believed legislation had both positive and negative effects, which were compounded by changes in the political and economic contexts. The case study reveals that government has a role in improving the status of farm labourers, with education and healthcare services requiring special attention. However, caution is needed to ensure that further reductions in farm employment are restricted.
- Full Text:
- Date Issued: 2013
- Authors: Roberts, Tamaryn , Antrobus, Geoffrey G
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142911 , vital:38175 , DOI: 10.1080/03031853.2013.778464
- Description: The status of South African farm workers has changed significantly over the past five decades. Using data from three major surveys conducted between 1957 and 2008, an Eastern Cape district was used as a case study to assess farmers’ perceptions of the changes that had occurred, particularly as a result of legislation. Considering the changes, the impacts on the farm labour market and wage and non-wage working conditions are analysed. The legislation focused on includes the Extension of Security of Tenure Act 62 (ESTA) of 1997, the Basic Conditions of Employment Act 75 (BCEA) of 1997 and minimum wage legislation. Farmers believed legislation had both positive and negative effects, which were compounded by changes in the political and economic contexts. The case study reveals that government has a role in improving the status of farm labourers, with education and healthcare services requiring special attention. However, caution is needed to ensure that further reductions in farm employment are restricted.
- Full Text:
- Date Issued: 2013
Finding the best clay: experiences of rural potter Alice Gqa Nongebeza contextualised
- Authors: Steele, John
- Date: 2013
- Language: English
- Type: text , Article
- Identifier: http://hdl.handle.net/11260/1023 , vital:30216
- Description: When creating artefacts that belong in the material world artists choose specific raw materials for particular reasons, including that selected resources are accessible and well suited to fitness for purpose and expression of intentions. Many potters in Africa are engaged in zero electricity usage ceramics practice, and each creative cycle usually starts with extracting clay from local sites according to preferences and well established procedures that may sometimes include certain rituals. Ways in which some potters who source their own clay are particular about certain factors that are thought to be capable of influencing the effectiveness of physical properties of that raw material are explored, with particular reference to what is known about the practices of Eastern Cape potter Alice Gqa Nongebeza, of Nkonxeni Village [31°37‘59.66“S, 29°23‘22.26“E], Tombo, near Port St Johns. Specific choices enacted by potters when gathering and using clayey raw materials are considered in order to better understand some aspects of conceptual and social frameworks that may influence clay extraction procedures. Thus, by means of comparisons between particular potter’s practices, as well as through analysis of interview material and observed events, this paper aims to contextualise how it transpired, inter alia, that clay seams close to the Nongebeza homestead were ignored by her in favour of a relatively distant and almost inaccessible site that yielded a particular clay well suited to her unique firing style of placing raw ware onto an already roaring bonfire, thereby effectively creating pots for daily use and enjoyment
- Full Text:
- Date Issued: 2013
- Authors: Steele, John
- Date: 2013
- Language: English
- Type: text , Article
- Identifier: http://hdl.handle.net/11260/1023 , vital:30216
- Description: When creating artefacts that belong in the material world artists choose specific raw materials for particular reasons, including that selected resources are accessible and well suited to fitness for purpose and expression of intentions. Many potters in Africa are engaged in zero electricity usage ceramics practice, and each creative cycle usually starts with extracting clay from local sites according to preferences and well established procedures that may sometimes include certain rituals. Ways in which some potters who source their own clay are particular about certain factors that are thought to be capable of influencing the effectiveness of physical properties of that raw material are explored, with particular reference to what is known about the practices of Eastern Cape potter Alice Gqa Nongebeza, of Nkonxeni Village [31°37‘59.66“S, 29°23‘22.26“E], Tombo, near Port St Johns. Specific choices enacted by potters when gathering and using clayey raw materials are considered in order to better understand some aspects of conceptual and social frameworks that may influence clay extraction procedures. Thus, by means of comparisons between particular potter’s practices, as well as through analysis of interview material and observed events, this paper aims to contextualise how it transpired, inter alia, that clay seams close to the Nongebeza homestead were ignored by her in favour of a relatively distant and almost inaccessible site that yielded a particular clay well suited to her unique firing style of placing raw ware onto an already roaring bonfire, thereby effectively creating pots for daily use and enjoyment
- Full Text:
- Date Issued: 2013
Fluorescence behavior of glutathione capped CdTe@ ZnS quantum dots chemically coordinated to zinc octacarboxy phthalocyanines
- Sekhosana, Kutloano E, Antunes, Edith M, Khene, Samson M, D'Souza, Sarah, Nyokong, Tebello
- Authors: Sekhosana, Kutloano E , Antunes, Edith M , Khene, Samson M , D'Souza, Sarah , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/242019 , vital:50993 , xlink:href="https://doi.org/10.1016/j.jlumin.2012.11.044"
- Description: Core–shell CdTe@ZnS quantum dots capped with glutathione (CdTe@ZnS–GSH) were covalently linked to zinc octacarboxy phthalocyanine (ZnPc(COOH)8). The conjugate was characterized by UV/Vis, infrared and X-Ray photoelectron spectroscopies as well as transmission electron and atomic force microscopies. The fluorescence quantum yields of the core CdTe capped with thioglycolic acid increased upon formation of the core-shell. Upon conjugation with ZnPc(COOH)8, the fluorescence quantum yield of CdTe@ZnS–GSH decreased due to energy transfer from the latter to the Pc. The average fluorescence lifetime of the CdTe@ZnS–GSH QD also decreased upon conjugation from 26.2 to 13.3 ns.
- Full Text:
- Date Issued: 2013
- Authors: Sekhosana, Kutloano E , Antunes, Edith M , Khene, Samson M , D'Souza, Sarah , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/242019 , vital:50993 , xlink:href="https://doi.org/10.1016/j.jlumin.2012.11.044"
- Description: Core–shell CdTe@ZnS quantum dots capped with glutathione (CdTe@ZnS–GSH) were covalently linked to zinc octacarboxy phthalocyanine (ZnPc(COOH)8). The conjugate was characterized by UV/Vis, infrared and X-Ray photoelectron spectroscopies as well as transmission electron and atomic force microscopies. The fluorescence quantum yields of the core CdTe capped with thioglycolic acid increased upon formation of the core-shell. Upon conjugation with ZnPc(COOH)8, the fluorescence quantum yield of CdTe@ZnS–GSH decreased due to energy transfer from the latter to the Pc. The average fluorescence lifetime of the CdTe@ZnS–GSH QD also decreased upon conjugation from 26.2 to 13.3 ns.
- Full Text:
- Date Issued: 2013
Fluorescence “switch on” of conjugates of CdTe@ ZnS quantum dots with Al, Ni and Zn tetraamino-phthalocyanines by hydrogen peroxide
- Adegoke, Oluwasesan, Khene, Samson M, Nyokong, Tebello
- Authors: Adegoke, Oluwasesan , Khene, Samson M , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241750 , vital:50966 , xlink:href="https://doi.org/10.1007/s10895-013-1222-x"
- Description: In this study, we have developed a novel nanoprobe for H2O2 based on the conjugation of CdTe@ZnS quantum dots (QDs) to different metal tetraamino-phthalocyanine (MTAPc): (M = (OAc)Al, {OAc = acetate}, Ni and Zn). Chemical coordination of the QDs to the MTAPc resulted in the fluorescence “switch off” of the linked QDs which was associated with Förster resonance energy transfer (FRET). In the presence of varying concentration of H2O2, the fluorescence of the linked QDs was progressively “switched on” and the FRET mechanism between the QDs and the MTAPc was disrupted. The sensitivity/limit of detection of the nanoprobe followed the order: QDs-ZnTAPc (2.2 μM) > QDs-NiTAPc (4.4 μM) > QDs-AlTAPc (9.8 μM) while the selectivity followed the order: QDs-NiTAPc > QDs-AlTAPc > QDs-ZnTAPc. The varying degree of sensitivity/selectivity and mechanism of detection is discussed in detail.
- Full Text:
- Date Issued: 2013
- Authors: Adegoke, Oluwasesan , Khene, Samson M , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241750 , vital:50966 , xlink:href="https://doi.org/10.1007/s10895-013-1222-x"
- Description: In this study, we have developed a novel nanoprobe for H2O2 based on the conjugation of CdTe@ZnS quantum dots (QDs) to different metal tetraamino-phthalocyanine (MTAPc): (M = (OAc)Al, {OAc = acetate}, Ni and Zn). Chemical coordination of the QDs to the MTAPc resulted in the fluorescence “switch off” of the linked QDs which was associated with Förster resonance energy transfer (FRET). In the presence of varying concentration of H2O2, the fluorescence of the linked QDs was progressively “switched on” and the FRET mechanism between the QDs and the MTAPc was disrupted. The sensitivity/limit of detection of the nanoprobe followed the order: QDs-ZnTAPc (2.2 μM) > QDs-NiTAPc (4.4 μM) > QDs-AlTAPc (9.8 μM) while the selectivity followed the order: QDs-NiTAPc > QDs-AlTAPc > QDs-ZnTAPc. The varying degree of sensitivity/selectivity and mechanism of detection is discussed in detail.
- Full Text:
- Date Issued: 2013
Fluorescence “turn on” probe for bromide ion using nanoconjugates of glutathione-capped CdTe@ ZnS quantum dots with nickel tetraamino-phthalocyanine
- Adegoke, Oluwasesan, Nyokong, Tebello
- Authors: Adegoke, Oluwasesan , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190479 , vital:44998 , xlink:href="https://doi.org/10.1016/j.jphotochem.2013.05.013"
- Description: In this paper, three differently sized glutathione (GSH)-capped CdTe@ZnS quantum dots (QDs) have been successfully conjugated to nickel tetraamino-phthalocyanine (NiTAPc) to form different QDs-NiTAPc nanocomplexes. Several techniques such as TEM, FT-IR, time-resolved fluorescence measurement and electronic spectroscopy were employed to characterize the nanocomplex. Bromide ion was chosen as a model anion to test the efficacy of the nanoprobe. The fluorescence of the nanoconjugate was “turned off” upon binding but was progressively “turned on” upon interaction with varying concentrations of bromide ion. Experimental results showed that the quantum size effect of nanocrystal QD determined the overall sensitivity and selectivity of the nanoprobe and followed the order QD563-NiTAPc > QD605-NiTAPc > QD621-NiTAPc. The mechanism of reaction is proposed.
- Full Text:
- Date Issued: 2013
- Authors: Adegoke, Oluwasesan , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190479 , vital:44998 , xlink:href="https://doi.org/10.1016/j.jphotochem.2013.05.013"
- Description: In this paper, three differently sized glutathione (GSH)-capped CdTe@ZnS quantum dots (QDs) have been successfully conjugated to nickel tetraamino-phthalocyanine (NiTAPc) to form different QDs-NiTAPc nanocomplexes. Several techniques such as TEM, FT-IR, time-resolved fluorescence measurement and electronic spectroscopy were employed to characterize the nanocomplex. Bromide ion was chosen as a model anion to test the efficacy of the nanoprobe. The fluorescence of the nanoconjugate was “turned off” upon binding but was progressively “turned on” upon interaction with varying concentrations of bromide ion. Experimental results showed that the quantum size effect of nanocrystal QD determined the overall sensitivity and selectivity of the nanoprobe and followed the order QD563-NiTAPc > QD605-NiTAPc > QD621-NiTAPc. The mechanism of reaction is proposed.
- Full Text:
- Date Issued: 2013
Forced degradation studies of clobetasol 17‐propionate in methanol, propylene glycol, as bulk drug and cream formulations by RP‐HPLC
- Fauzee, Ayesha F, Walker, Roderick B
- Authors: Fauzee, Ayesha F , Walker, Roderick B
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184005 , vital:44154 , xlink:href="https://doi.org/10.1002/jssc.201200969"
- Description: A rapid, simple, stability-indicating forced degradation study of clobetasol 17-propionate was conducted using RP-HPLC. The method was used to analyze clobetasol 17-propionate in methanol, propylene glycol, and a cream formulation. Isocratic elution of clobetasol and its degradation products was achieved using a Nova-Pak® 4 μm C18 150 mm × 3.9 mm id cartridge column and a mobile phase of methanol: water (68:32 v/v) at a flow rate of 0.9 mL min−1. Quantitation was achieved with UV detection at 239 nm. Nondegraded clobetasol was eluted at a retention time of 6.0 min. Clobetasol 17-propionate was subjected to different stress conditions viz., acidic, basic, heat, oxidation, light, and neutral hydrolysis. The greatest degradation occurred under strong base and oxidative conditions. Strong base-degraded clobetasol produced additional peaks at retention times of 1.8, 4.0, 5.0, and 8.0 min and clobetasol oxidation degradation peaks eluted at 2.2 and 24 min. Complete validation was performed for linearity, accuracy, and precision over the concentration range 0.15–15 μg mL−1. All data were analyzed statistically and this RP-HPLC method proved to be accurate, precise, linear, and stability indicating for the quantitation of clobetasol 17-propionate in methanol, propylene glycol, and cream formulations.
- Full Text:
- Date Issued: 2013
- Authors: Fauzee, Ayesha F , Walker, Roderick B
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184005 , vital:44154 , xlink:href="https://doi.org/10.1002/jssc.201200969"
- Description: A rapid, simple, stability-indicating forced degradation study of clobetasol 17-propionate was conducted using RP-HPLC. The method was used to analyze clobetasol 17-propionate in methanol, propylene glycol, and a cream formulation. Isocratic elution of clobetasol and its degradation products was achieved using a Nova-Pak® 4 μm C18 150 mm × 3.9 mm id cartridge column and a mobile phase of methanol: water (68:32 v/v) at a flow rate of 0.9 mL min−1. Quantitation was achieved with UV detection at 239 nm. Nondegraded clobetasol was eluted at a retention time of 6.0 min. Clobetasol 17-propionate was subjected to different stress conditions viz., acidic, basic, heat, oxidation, light, and neutral hydrolysis. The greatest degradation occurred under strong base and oxidative conditions. Strong base-degraded clobetasol produced additional peaks at retention times of 1.8, 4.0, 5.0, and 8.0 min and clobetasol oxidation degradation peaks eluted at 2.2 and 24 min. Complete validation was performed for linearity, accuracy, and precision over the concentration range 0.15–15 μg mL−1. All data were analyzed statistically and this RP-HPLC method proved to be accurate, precise, linear, and stability indicating for the quantitation of clobetasol 17-propionate in methanol, propylene glycol, and cream formulations.
- Full Text:
- Date Issued: 2013