Development and assessment of an oxytocin parenteral dosage form prepared using pluronic ® F127
- Authors: Chaibva, Faith Anesu
- Date: 2007
- Subjects: Oxytocin -- Therapeutic use , Drugs -- Dosage forms , Pregnancy -- Complications -- Management
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3747 , http://hdl.handle.net/10962/d1003225 , Oxytocin -- Therapeutic use , Drugs -- Dosage forms , Pregnancy -- Complications -- Management
- Full Text:
- Authors: Chaibva, Faith Anesu
- Date: 2007
- Subjects: Oxytocin -- Therapeutic use , Drugs -- Dosage forms , Pregnancy -- Complications -- Management
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3747 , http://hdl.handle.net/10962/d1003225 , Oxytocin -- Therapeutic use , Drugs -- Dosage forms , Pregnancy -- Complications -- Management
- Full Text:
Development and in vitro evaluation of a clobetasol 17-propionate topical cream formulation
- Authors: Wa Kasongo, Kasongo
- Date: 2007
- Subjects: Adrenocortical hormones , Adrenocortical hormones -- Physiological effect , Drugs -- Testing , Drug development , Dermatopharmacology
- Language: English
- Type: Thesis , Masters , MPharm
- Identifier: vital:3799 , http://hdl.handle.net/10962/d1003277 , Adrenocortical hormones , Adrenocortical hormones -- Physiological effect , Drugs -- Testing , Drug development , Dermatopharmacology
- Description: One of the primary contributing factors to the escalating costs of health care is the high cost of innovator pharmaceutical products. As a consequence, health authorities in various countries and in particular in the developing world have identified generic prescribing and generic substitution as possible strategies to contain the escalating costs of health care provision. There is therefore a need for formulation scientists in developing countries to invest more time in the research and development of generic formulations. Clobetasol 17-propionate (CP) generic cream formulations containing 0.05% w/w of the drug were manufactured and characterized using in vitro testing. Formulation development studies were preceded by the development and validation of an RP-HPLC with UV detection for the quantitation and characterization of CP in innovator and generic cream formulations during formulation development and assessment studies. Furthermore the in vitro release ates of CP release from innovator and generic cream formulations were monitored using a validated in vitro release test method developed in these studies. The formulation of CP cream products was accomplished using a variety of commercially available mixed primary emulsifiers, such as Estol® 1474, Ritapro® 200, Emulcire® 61 WL and Gelot® 64. Successful formulations were selected based on their ability to remain physically stable immediately after manufacture and for 24 hours after storage at room temperature (22°C). Estol® 1474 was found to produce an unstable cream and was therefore not investigated further. The other three emulgents produced stable creams, but only the in vitro release profile of CP from a cream manufactured to contain Gelot® 64 was found to be statistically similar to that of the innovator formulation. Therefore the cream containing Gelot® 64 was selected as the most appropriate prototype generic cream formulation and was characterized in vitro in terms of CP content, viscosity, pH and in vitro release rate. Data generated from these studies were compared to those of the innovator product, Dermovate® cream, using statistical methods. The CP content, pH and in vitro release rate data of the CP formulation were similar to those of the innovator product, however the intrinsic viscosity of Dermovate® cream was almost three (3) times greater than the intrinsic viscosity of the test formulation developed using Gelot® 64. The CP cream formulation developed in these studies was stored for 4 weeks at 40 ± 2°C and 25 ± 5% RH in an incubator and the formulation was found to be stable. A formulation has been developed and assessed and found to be suitable for use as a topical semi-solid dosage form for CP.
- Full Text:
- Authors: Wa Kasongo, Kasongo
- Date: 2007
- Subjects: Adrenocortical hormones , Adrenocortical hormones -- Physiological effect , Drugs -- Testing , Drug development , Dermatopharmacology
- Language: English
- Type: Thesis , Masters , MPharm
- Identifier: vital:3799 , http://hdl.handle.net/10962/d1003277 , Adrenocortical hormones , Adrenocortical hormones -- Physiological effect , Drugs -- Testing , Drug development , Dermatopharmacology
- Description: One of the primary contributing factors to the escalating costs of health care is the high cost of innovator pharmaceutical products. As a consequence, health authorities in various countries and in particular in the developing world have identified generic prescribing and generic substitution as possible strategies to contain the escalating costs of health care provision. There is therefore a need for formulation scientists in developing countries to invest more time in the research and development of generic formulations. Clobetasol 17-propionate (CP) generic cream formulations containing 0.05% w/w of the drug were manufactured and characterized using in vitro testing. Formulation development studies were preceded by the development and validation of an RP-HPLC with UV detection for the quantitation and characterization of CP in innovator and generic cream formulations during formulation development and assessment studies. Furthermore the in vitro release ates of CP release from innovator and generic cream formulations were monitored using a validated in vitro release test method developed in these studies. The formulation of CP cream products was accomplished using a variety of commercially available mixed primary emulsifiers, such as Estol® 1474, Ritapro® 200, Emulcire® 61 WL and Gelot® 64. Successful formulations were selected based on their ability to remain physically stable immediately after manufacture and for 24 hours after storage at room temperature (22°C). Estol® 1474 was found to produce an unstable cream and was therefore not investigated further. The other three emulgents produced stable creams, but only the in vitro release profile of CP from a cream manufactured to contain Gelot® 64 was found to be statistically similar to that of the innovator formulation. Therefore the cream containing Gelot® 64 was selected as the most appropriate prototype generic cream formulation and was characterized in vitro in terms of CP content, viscosity, pH and in vitro release rate. Data generated from these studies were compared to those of the innovator product, Dermovate® cream, using statistical methods. The CP content, pH and in vitro release rate data of the CP formulation were similar to those of the innovator product, however the intrinsic viscosity of Dermovate® cream was almost three (3) times greater than the intrinsic viscosity of the test formulation developed using Gelot® 64. The CP cream formulation developed in these studies was stored for 4 weeks at 40 ± 2°C and 25 ± 5% RH in an incubator and the formulation was found to be stable. A formulation has been developed and assessed and found to be suitable for use as a topical semi-solid dosage form for CP.
- Full Text:
Development of a regional GPS-based ionospheric TEC model for South Africa
- Opperman, Ben D L, Cilliers, Pierre J, McKinnell, Lee-Anne, Haggard, Raymond
- Authors: Opperman, Ben D L , Cilliers, Pierre J , McKinnell, Lee-Anne , Haggard, Raymond
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6799 , http://hdl.handle.net/10962/d1003925
- Description: Advances in South African space physics research and related disciplines require better spatial and time resolution ionospheric information than was previously possible with the existing ionosonde network. A GPS-based, variable degree adjusted spherical harmonic (ASHA) model was developed for near real-time regional ionospheric total electron content (TEC) mapping over South Africa. Slant TEC values along oblique GPS signal paths are quantified from a network of GPS receivers and converted to vertical TEC by means of the single layer mapping function. The ASHA model coefficients and GPS differential biases are estimated from vertical TEC at the ionospheric pierce points and used to interpolate TEC at any location within the region of interest. Diurnal TEC variations with one minute time resolution and time-varying 2D regional TEC maps are constructed. In order to validate the ASHA method, simulations with an IRI ionosphere were performed, while the ASHA results from actual data were compared with two independent GPS-based methodologies and measured ionosonde data.
- Full Text:
- Authors: Opperman, Ben D L , Cilliers, Pierre J , McKinnell, Lee-Anne , Haggard, Raymond
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6799 , http://hdl.handle.net/10962/d1003925
- Description: Advances in South African space physics research and related disciplines require better spatial and time resolution ionospheric information than was previously possible with the existing ionosonde network. A GPS-based, variable degree adjusted spherical harmonic (ASHA) model was developed for near real-time regional ionospheric total electron content (TEC) mapping over South Africa. Slant TEC values along oblique GPS signal paths are quantified from a network of GPS receivers and converted to vertical TEC by means of the single layer mapping function. The ASHA model coefficients and GPS differential biases are estimated from vertical TEC at the ionospheric pierce points and used to interpolate TEC at any location within the region of interest. Diurnal TEC variations with one minute time resolution and time-varying 2D regional TEC maps are constructed. In order to validate the ASHA method, simulations with an IRI ionosphere were performed, while the ASHA results from actual data were compared with two independent GPS-based methodologies and measured ionosonde data.
- Full Text:
Development of a school environmental policy to enable active learning in the context of the National Curriculum Statement
- Authors: Mvula-Jamela, Lungiswa Gwen
- Date: 2007
- Subjects: Environmental policy -- Study and teaching (Primary) -- South Africa -- Grahamstown Environmental education -- Study and teaching (Primary) -- South Africa -- Grahamstown Environmental education -- Activity programs -- South Africa -- Grahamstown Environmental education -- South Africa -- Grahamstown -- Case studies Competency-based education -- South Africa -- Grahamstown Teacher participation in curriculum planning -- South Africa -- Grahamstown
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1958 , http://hdl.handle.net/10962/d1008376
- Description: The transformation processes occurring in the South African curriculum context has highlighted a need for improving ways of interpreting and implementing curriculum requirements, in ways that are relevant to the context of learners and their experiences. Outcomes Based Education (OBE) encourages teachers to develop learner centred and active learning approaches. In this research I explore the development of how a School Environmental Policy can contribute to active learning in the context of the National Curriculum Statement for Grades R-9 (NCS R-9). I employed a participatory action research approach in which I worked with other teachers in my school to develop a School Environmental Policy, and then implement associated lessons. In cycle 1 this research focused on the School Environmental Policy development processes. In cycle 2 the research focused on designing and implementing three Lesson Plans in Makana Public Primary School (in three phases). I used a range of data generation strategies such as observations, use of a reflective journal, semi-structured interviews, focus group discussions, a workshop, photographs and document analysis to generate data for the study. All participants collaboratively discussed and agreed upon the research , and the two teachers who developed the lessons with me also reflected on the process of Lesson Planning and active learning, but I was responsible for the final interpretation presented in this thesis. The research indicates that the School Environmental Policy led to the planning of active learning processes and that the School Environmental Policy and the active learn ing approach are consistent with OBE policy and philosophy. The study also indicates that the School Environmental Policy and the active learning approach strengthened the use of Learning Outcomes, but not necessarily Assessment Standards and that the active learning approach promoted enquiry in lessons. The research further indicates that the School Environmental Policy and active learning processes contributed to school improvement and work towards a healthy environment. The School Environmental Policy also encouraged educators to address school community environmental issues and build stronger links with parents. The study also led to a set of recommendations to improve the School Environmental Policy and active learning process in ways that address the NCS requirements for learning and assessment.
- Full Text:
- Authors: Mvula-Jamela, Lungiswa Gwen
- Date: 2007
- Subjects: Environmental policy -- Study and teaching (Primary) -- South Africa -- Grahamstown Environmental education -- Study and teaching (Primary) -- South Africa -- Grahamstown Environmental education -- Activity programs -- South Africa -- Grahamstown Environmental education -- South Africa -- Grahamstown -- Case studies Competency-based education -- South Africa -- Grahamstown Teacher participation in curriculum planning -- South Africa -- Grahamstown
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1958 , http://hdl.handle.net/10962/d1008376
- Description: The transformation processes occurring in the South African curriculum context has highlighted a need for improving ways of interpreting and implementing curriculum requirements, in ways that are relevant to the context of learners and their experiences. Outcomes Based Education (OBE) encourages teachers to develop learner centred and active learning approaches. In this research I explore the development of how a School Environmental Policy can contribute to active learning in the context of the National Curriculum Statement for Grades R-9 (NCS R-9). I employed a participatory action research approach in which I worked with other teachers in my school to develop a School Environmental Policy, and then implement associated lessons. In cycle 1 this research focused on the School Environmental Policy development processes. In cycle 2 the research focused on designing and implementing three Lesson Plans in Makana Public Primary School (in three phases). I used a range of data generation strategies such as observations, use of a reflective journal, semi-structured interviews, focus group discussions, a workshop, photographs and document analysis to generate data for the study. All participants collaboratively discussed and agreed upon the research , and the two teachers who developed the lessons with me also reflected on the process of Lesson Planning and active learning, but I was responsible for the final interpretation presented in this thesis. The research indicates that the School Environmental Policy led to the planning of active learning processes and that the School Environmental Policy and the active learn ing approach are consistent with OBE policy and philosophy. The study also indicates that the School Environmental Policy and the active learning approach strengthened the use of Learning Outcomes, but not necessarily Assessment Standards and that the active learning approach promoted enquiry in lessons. The research further indicates that the School Environmental Policy and active learning processes contributed to school improvement and work towards a healthy environment. The School Environmental Policy also encouraged educators to address school community environmental issues and build stronger links with parents. The study also led to a set of recommendations to improve the School Environmental Policy and active learning process in ways that address the NCS requirements for learning and assessment.
- Full Text:
Development of an in-situ ß-D-Glucuronidase diagnostic moraxella-based biosensor for potential application in the monitoring of water polluted by faecal material in South Africa
- Authors: Togo, Chamunorwa Aloius
- Date: 2007
- Subjects: Water quality management -- South Africa Water quality bioassay -- South Africa Sewage sludge -- South Africa -- Management Water -- Purification -- Biological treatment -- South Africa Biosensors
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3947 , http://hdl.handle.net/10962/d1004006
- Description: The prevention of outbreaks of waterborne diseases remains a major challenge to public health service providers globally. One of the major obstacles in this effort is the unavailability of on-line and real-time methods for rapid monitoring of faecal pollution to facilitate early warning of contamination of drinking water. The main objective of this study was to develop a β-glucuronidase (GUD)-based method that could be used for the on-line and real-time monitoring of microbial water quality. GUD is a marker enzyme for the faecal indicator bacteria Escherichia coli. This enzyme breaks down the synthetic substrate p-nitrophenyl-β-D-glucuronide (PNPG) to D-glucuronic acid and p-nitrophenol (PNP), which turns yellow under alkaline pH. The enzymatically produced PNP was used to detect GUD activity. In situ GUD assays were performed using running and stagnant water samples from the Bloukrans River, Grahamstown, South Africa. The physico-chemical properties of environmental GUD were determined, after which a liquid bioprobe and a microbial biosensor modified with Moraxella 1A species for the detection of the enzyme activity were developed. In order to determine the reliability and sensitivity of these methods, regression analyses for each method versus E. coli colony forming units (CFU) were performed. The storage stabilities of the bioprobe and biosensor were also investigated. The physico-chemical properties of in situ GUD were different from those of its commercially available counterpart. The temperature optimum for the former was between 35 and 40 °C while for the latter it was 45 °C. Commercial (reference) GUD had a pH optimum of 8.0 while the environmental counterpart exhibited a broad pH optimum of between pH 5.0 and 8.0. The liquid bioprobe had a limit of detection (LOD) of GUD activity equivalent to 2 CFU/100 ml and a detection time of 24 h. The method was less labour intensive and costly than the culturing method. The liquid bioprobe was stable for at least four weeks at room temperature (20 ± 2 °C). The biosensor was prepared by modifying a glassy carbon electrode with PNP degrading Moraxella 1A cells. The biosensor was 100 times more sensitive and rapid (5-20 min) than the spectrophotometric method (24 h), and was also able to detect GUD activity of viable but non-culturable cells. Thus it was more sensitive than the culturing method. Furthermore, the biosensor was selective and costeffective. The possibility of using a Pseudomonas putida JS444 biosensor was also investigated, but it was not as sensitive and selective as the Moraxella 1A biosensor. The Moraxella biosensor, therefore, offered the best option for on-line and real-time microbial water quality monitoring in South African river waters and drinking water supplies.
- Full Text:
- Authors: Togo, Chamunorwa Aloius
- Date: 2007
- Subjects: Water quality management -- South Africa Water quality bioassay -- South Africa Sewage sludge -- South Africa -- Management Water -- Purification -- Biological treatment -- South Africa Biosensors
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3947 , http://hdl.handle.net/10962/d1004006
- Description: The prevention of outbreaks of waterborne diseases remains a major challenge to public health service providers globally. One of the major obstacles in this effort is the unavailability of on-line and real-time methods for rapid monitoring of faecal pollution to facilitate early warning of contamination of drinking water. The main objective of this study was to develop a β-glucuronidase (GUD)-based method that could be used for the on-line and real-time monitoring of microbial water quality. GUD is a marker enzyme for the faecal indicator bacteria Escherichia coli. This enzyme breaks down the synthetic substrate p-nitrophenyl-β-D-glucuronide (PNPG) to D-glucuronic acid and p-nitrophenol (PNP), which turns yellow under alkaline pH. The enzymatically produced PNP was used to detect GUD activity. In situ GUD assays were performed using running and stagnant water samples from the Bloukrans River, Grahamstown, South Africa. The physico-chemical properties of environmental GUD were determined, after which a liquid bioprobe and a microbial biosensor modified with Moraxella 1A species for the detection of the enzyme activity were developed. In order to determine the reliability and sensitivity of these methods, regression analyses for each method versus E. coli colony forming units (CFU) were performed. The storage stabilities of the bioprobe and biosensor were also investigated. The physico-chemical properties of in situ GUD were different from those of its commercially available counterpart. The temperature optimum for the former was between 35 and 40 °C while for the latter it was 45 °C. Commercial (reference) GUD had a pH optimum of 8.0 while the environmental counterpart exhibited a broad pH optimum of between pH 5.0 and 8.0. The liquid bioprobe had a limit of detection (LOD) of GUD activity equivalent to 2 CFU/100 ml and a detection time of 24 h. The method was less labour intensive and costly than the culturing method. The liquid bioprobe was stable for at least four weeks at room temperature (20 ± 2 °C). The biosensor was prepared by modifying a glassy carbon electrode with PNP degrading Moraxella 1A cells. The biosensor was 100 times more sensitive and rapid (5-20 min) than the spectrophotometric method (24 h), and was also able to detect GUD activity of viable but non-culturable cells. Thus it was more sensitive than the culturing method. Furthermore, the biosensor was selective and costeffective. The possibility of using a Pseudomonas putida JS444 biosensor was also investigated, but it was not as sensitive and selective as the Moraxella 1A biosensor. The Moraxella biosensor, therefore, offered the best option for on-line and real-time microbial water quality monitoring in South African river waters and drinking water supplies.
- Full Text:
Development of Cactoblastis cactorum (Berg)(Lepidoptera: pyralidae) on six north American Opuntia species
- Mafokoane, L D, Zimmermann, Helmuth G, Hill, Martin P
- Authors: Mafokoane, L D , Zimmermann, Helmuth G , Hill, Martin P
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451346 , vital:75042 , https://hdl.handle.net/10520/EJC32740
- Description: Cactoblastis cactorum (Berg) (Lepidoptera : Pyralidae) has been used as a biological control agent of several Opuntia species around the world and is widely assumed to be a generalist on host plants within the genus Opuntia. The recent arrival and spread of C. cactorum on the North American mainland has raised concerns for the native species of Opuntia that are being utilized as hosts by the moth. To confirm that C. cactorum is a threat to a wide range of Opuntia species in North America, the host range of the moths was scrutinized in South Africa, where larval development could be monitored on several Opuntia species under natural conditions. Development was monitored on Opuntia ficus-indica L. Miller, O. engelmannii Salm-Dyke, O. fulgida Englm, O. imbricata (Haworth) de Candolle, O. stricta Haworth and O. leucotrichta DC. Larval survival, egg to pupation, was highest on O. ficus-indica (79.2%) followed by O. engelmannii (57.5 %), O. stricta (55.0 %), O. leucotrichta (29.2 %), O. fulgida (24.2 %) and O. imbricata (16.7 %). Male and female pupal mass was highest, and duration of development shortest on O. ficus-indica. In adult multi-choice oviposition trials, females laid significantly more egg sticks on O. ficus-indica than on the other species. Although O. ficusindica is the preferred host for C. cactorum in South Africa, the moth is nevertheless able to utilize several other species of Opuntia as hosts.
- Full Text:
- Authors: Mafokoane, L D , Zimmermann, Helmuth G , Hill, Martin P
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451346 , vital:75042 , https://hdl.handle.net/10520/EJC32740
- Description: Cactoblastis cactorum (Berg) (Lepidoptera : Pyralidae) has been used as a biological control agent of several Opuntia species around the world and is widely assumed to be a generalist on host plants within the genus Opuntia. The recent arrival and spread of C. cactorum on the North American mainland has raised concerns for the native species of Opuntia that are being utilized as hosts by the moth. To confirm that C. cactorum is a threat to a wide range of Opuntia species in North America, the host range of the moths was scrutinized in South Africa, where larval development could be monitored on several Opuntia species under natural conditions. Development was monitored on Opuntia ficus-indica L. Miller, O. engelmannii Salm-Dyke, O. fulgida Englm, O. imbricata (Haworth) de Candolle, O. stricta Haworth and O. leucotrichta DC. Larval survival, egg to pupation, was highest on O. ficus-indica (79.2%) followed by O. engelmannii (57.5 %), O. stricta (55.0 %), O. leucotrichta (29.2 %), O. fulgida (24.2 %) and O. imbricata (16.7 %). Male and female pupal mass was highest, and duration of development shortest on O. ficus-indica. In adult multi-choice oviposition trials, females laid significantly more egg sticks on O. ficus-indica than on the other species. Although O. ficusindica is the preferred host for C. cactorum in South Africa, the moth is nevertheless able to utilize several other species of Opuntia as hosts.
- Full Text:
Development of written information for antiretroviral therapy: comprehension in a Tanzanian population
- Mwingira, Betty, Dowse, Roslind
- Authors: Mwingira, Betty , Dowse, Roslind
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6404 , http://hdl.handle.net/10962/d1006477
- Description: Objective To design and develop a simple, easily readable patient information leaflet (PIL) for a commonly used antiretroviral (ARV) regimen and to evaluate its readability and acceptability in a Tanzanian population. Method A PIL incorporating simple text and pictograms was designed for the antiretroviral regimen of stavudine, lamivudine and efavirenz. The PIL was designed according to established good design guidelines, modified during a multi-stage iterative testing process and piloted in a South African Xhosa population. The PIL was made available in both English and Kiswahili. Sixty Tanzanian participants who were not taking ARVs were interviewed. They were asked to read the PIL in the language of their choice and were then asked a series of two-part questions; the first part required participants to locate the information in the PIL, after which they were asked to explain the information in their own words. Acceptability was assessed through close-ended questions and open-ended feedback. The influence of selected patient characteristics on comprehension of the PIL was investigated using one-way ANOVA and t-tests for independent samples with a significance level set at 0.05. Main outcome measure Comprehension of the written information in an overall percentage understanding. Results The overall average percentage comprehension of the PIL was 95%. The target set by the EC guideline that at least 80% of participants correctly locate and understand the information was achieved for 19 of the 20 questions. Five of the six instructions illustrated by pictograms were correctly understood by all participants. The only patient characteristics significantly associated with comprehension were educational level and self-reported ease of reading the PIL. Acceptability of the PIL was high and positive comments were associated with simplicity, good design, easy readability and user-friendliness, the latter enhanced by the inclusion of pictograms. Conclusion The PIL designed for this study was shown to be effective in communicating information about ARVs. Patient characteristics must be taken into account when developing written information, and the final document must be tested for comprehension in the target population.
- Full Text:
- Authors: Mwingira, Betty , Dowse, Roslind
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6404 , http://hdl.handle.net/10962/d1006477
- Description: Objective To design and develop a simple, easily readable patient information leaflet (PIL) for a commonly used antiretroviral (ARV) regimen and to evaluate its readability and acceptability in a Tanzanian population. Method A PIL incorporating simple text and pictograms was designed for the antiretroviral regimen of stavudine, lamivudine and efavirenz. The PIL was designed according to established good design guidelines, modified during a multi-stage iterative testing process and piloted in a South African Xhosa population. The PIL was made available in both English and Kiswahili. Sixty Tanzanian participants who were not taking ARVs were interviewed. They were asked to read the PIL in the language of their choice and were then asked a series of two-part questions; the first part required participants to locate the information in the PIL, after which they were asked to explain the information in their own words. Acceptability was assessed through close-ended questions and open-ended feedback. The influence of selected patient characteristics on comprehension of the PIL was investigated using one-way ANOVA and t-tests for independent samples with a significance level set at 0.05. Main outcome measure Comprehension of the written information in an overall percentage understanding. Results The overall average percentage comprehension of the PIL was 95%. The target set by the EC guideline that at least 80% of participants correctly locate and understand the information was achieved for 19 of the 20 questions. Five of the six instructions illustrated by pictograms were correctly understood by all participants. The only patient characteristics significantly associated with comprehension were educational level and self-reported ease of reading the PIL. Acceptability of the PIL was high and positive comments were associated with simplicity, good design, easy readability and user-friendliness, the latter enhanced by the inclusion of pictograms. Conclusion The PIL designed for this study was shown to be effective in communicating information about ARVs. Patient characteristics must be taken into account when developing written information, and the final document must be tested for comprehension in the target population.
- Full Text:
Direct-use values of non-timber forest products from two areas on the Transkei Wild Coast
- Shackleton, Charlie M, Timmermans, Herman G, Nongwe, N, Hamer, Nicholas G, Palmer, N R
- Authors: Shackleton, Charlie M , Timmermans, Herman G , Nongwe, N , Hamer, Nicholas G , Palmer, N R
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181268 , vital:43714 , xlink:href="https://doi.org/10.1080/03031853.2007.9523764"
- Description: It is now widely appreciated internationally that rural communities make extensive use of wild resources, and that this use has significant direct use value. The number of case studies in South Africa that have valued the use of such resources are small, albeit growing. Yet none of them have been from coastal sites, which would include use of marine resources, nor have previous studies included the non-biological resources of sand and clay for building purposes. This paper addresses this gap, through examination of the role and value of wild resources in rural livelihoods of households in the Ntubeni and Cwebe areas of the Transkei Wild Coast in the Eastern Cape. Households used a wide range of resources collected from the surrounding communal lands and the Dwesa Cwebe Nature Reserve. Major differences between the sites were the widespread use of bushmeat, shellfish and building sand at Ntubeni compared with relatively small use of these three resources at Cwebe. These differences resulted in a markedly higher, gross, annual, direct-use value at Ntubeni than at Cwebe. The gross, annual, direct-use value averaged across all resources (excluding medicinal plants) and all households (user and non-users) was over R12 000 at Ntubeni, compared to R4 858 at Cwebe. At Ntubeni over half of the total annual direct-use value was contributed by fish and shellfish, indicating the need for more studies in coastal areas. A similar pattern was not evident at Cwebe, because residents did not have access to a rocky shoreline outside of the marine reserve. Local trade was highly variable, both between resources and between households. Averaging the value of trade across all households (i.e. traders and non-traders), gave a total gross, annual value of R1 660 and R600 at Ntubeni and Cwebe, respectively.
- Full Text:
- Authors: Shackleton, Charlie M , Timmermans, Herman G , Nongwe, N , Hamer, Nicholas G , Palmer, N R
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181268 , vital:43714 , xlink:href="https://doi.org/10.1080/03031853.2007.9523764"
- Description: It is now widely appreciated internationally that rural communities make extensive use of wild resources, and that this use has significant direct use value. The number of case studies in South Africa that have valued the use of such resources are small, albeit growing. Yet none of them have been from coastal sites, which would include use of marine resources, nor have previous studies included the non-biological resources of sand and clay for building purposes. This paper addresses this gap, through examination of the role and value of wild resources in rural livelihoods of households in the Ntubeni and Cwebe areas of the Transkei Wild Coast in the Eastern Cape. Households used a wide range of resources collected from the surrounding communal lands and the Dwesa Cwebe Nature Reserve. Major differences between the sites were the widespread use of bushmeat, shellfish and building sand at Ntubeni compared with relatively small use of these three resources at Cwebe. These differences resulted in a markedly higher, gross, annual, direct-use value at Ntubeni than at Cwebe. The gross, annual, direct-use value averaged across all resources (excluding medicinal plants) and all households (user and non-users) was over R12 000 at Ntubeni, compared to R4 858 at Cwebe. At Ntubeni over half of the total annual direct-use value was contributed by fish and shellfish, indicating the need for more studies in coastal areas. A similar pattern was not evident at Cwebe, because residents did not have access to a rocky shoreline outside of the marine reserve. Local trade was highly variable, both between resources and between households. Averaging the value of trade across all households (i.e. traders and non-traders), gave a total gross, annual value of R1 660 and R600 at Ntubeni and Cwebe, respectively.
- Full Text:
Does 'African mathematics' facilitate access to mathematics?: towards an ongoing critical analysis of ethnomathematics in a South African context
- Horsthemke, Kai, Schäfer, Marc
- Authors: Horsthemke, Kai , Schäfer, Marc
- Date: 2007
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141004 , vital:37936 , https://0-hdl.handle.net.wam.seals.ac.za/10520/EJC20885
- Description: Mosibudi Mangena, the Minister of Science and Technology, said in an address to the Annual Congress of the South African Mathematical Society at the University of the Potchefstroom, November 2, 2004: "There is one thing we need to address before anything else. We need to increase the number of young people, particularly blacks and women, who are able to successfully complete the first course in Mathematics at our universities." How is this to be achieved? A popular trend involves a call for the introduction and incorporation of so-called ethnomathematics, and more particularly 'African mathematics', into secondary and tertiary curricula. Although acknowledging the obvious benefits of so-called ethnomathematics, this paper critically analyses three aspects of ethnomathematics that have been neglected in past critiques. Our focus is not on the relationship as such between ethnomathematics and mathematics education. Our critique involves (1) epistemological and logical misgivings, (2) a new look at practices and skills, (3) concerns about embracing 'African mathematics' as valid and valuable - just because it is African.
- Full Text:
- Authors: Horsthemke, Kai , Schäfer, Marc
- Date: 2007
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141004 , vital:37936 , https://0-hdl.handle.net.wam.seals.ac.za/10520/EJC20885
- Description: Mosibudi Mangena, the Minister of Science and Technology, said in an address to the Annual Congress of the South African Mathematical Society at the University of the Potchefstroom, November 2, 2004: "There is one thing we need to address before anything else. We need to increase the number of young people, particularly blacks and women, who are able to successfully complete the first course in Mathematics at our universities." How is this to be achieved? A popular trend involves a call for the introduction and incorporation of so-called ethnomathematics, and more particularly 'African mathematics', into secondary and tertiary curricula. Although acknowledging the obvious benefits of so-called ethnomathematics, this paper critically analyses three aspects of ethnomathematics that have been neglected in past critiques. Our focus is not on the relationship as such between ethnomathematics and mathematics education. Our critique involves (1) epistemological and logical misgivings, (2) a new look at practices and skills, (3) concerns about embracing 'African mathematics' as valid and valuable - just because it is African.
- Full Text:
Does the endangered Knysna seahorse, Hippocampus capensis, have a preference for aquatic vegetation type, cover or height?
- Teske, Peter R, Lockyear, Jaqueline F, Hecht, Thomas, Kaiser, Horst
- Authors: Teske, Peter R , Lockyear, Jaqueline F , Hecht, Thomas , Kaiser, Horst
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6775 , http://hdl.handle.net/10962/d1008082
- Description: The Knysna seahorse, Hippocampus capensis, is an endangered teleost confined to three South African estuaries. Its abundance within these systems is low and distributions are patchy. Consequently, monitoring population sizes is labour-intensive. The aim of this study was to establish if Knynsa seahorses are associated with specific regions within the estuaries, on which conservation efforts could concentrate. The relationship of Knysna seahorses with aquatic vegetation was analysed in the Knysna Estuary (the largest of the three estuarine systems inhabited by H. capensis) to determine whether this species shows a preference for a particular plant species, vegetation density or vegetation height. Seahorses were associated with five dominant aquatic plants: Zostera capensis, Caulerpa filiformis, Codium extricatum, Halophila ovalis and Ruppia cirrhosa. Together, these comprised 96% of the submerged objects with which seahorses were associated. The relative abundance of plant species changed along the estuary, but seahorses were present throughout the system, except at the estuary mouth, which was characterized by low plant densities and strong currents. No significant difference was found between the proportion of plant species present in a particular region of the estuary and the proportion of plants that seahorses used as holdfasts. However, when Z. capensis and C. filiformis were present at the same sites, adult seahorses preferred C. filiformis as holdfast. Adult seahorse density (individuals/m²) was significantly correlated with percentage vegetation cover and with holdfast length, but juvenile seahorse density was not. Nonetheless, significantly more adult and juvenile seahorses were found at sites characterized by high vegetation cover (>75%) than at sites with lower cover. Our results indicate that although there is some evidence that Knynsa seahorses prefer certain plant species over others, they are likely to be encountered anywhere in the estuary where aquatic plants are present. Conservation efforts in the Knysna Estuary should thus concentrate on such vegetated areas, which comprise approximately 11% of the total submerged surface area.
- Full Text:
- Authors: Teske, Peter R , Lockyear, Jaqueline F , Hecht, Thomas , Kaiser, Horst
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6775 , http://hdl.handle.net/10962/d1008082
- Description: The Knysna seahorse, Hippocampus capensis, is an endangered teleost confined to three South African estuaries. Its abundance within these systems is low and distributions are patchy. Consequently, monitoring population sizes is labour-intensive. The aim of this study was to establish if Knynsa seahorses are associated with specific regions within the estuaries, on which conservation efforts could concentrate. The relationship of Knysna seahorses with aquatic vegetation was analysed in the Knysna Estuary (the largest of the three estuarine systems inhabited by H. capensis) to determine whether this species shows a preference for a particular plant species, vegetation density or vegetation height. Seahorses were associated with five dominant aquatic plants: Zostera capensis, Caulerpa filiformis, Codium extricatum, Halophila ovalis and Ruppia cirrhosa. Together, these comprised 96% of the submerged objects with which seahorses were associated. The relative abundance of plant species changed along the estuary, but seahorses were present throughout the system, except at the estuary mouth, which was characterized by low plant densities and strong currents. No significant difference was found between the proportion of plant species present in a particular region of the estuary and the proportion of plants that seahorses used as holdfasts. However, when Z. capensis and C. filiformis were present at the same sites, adult seahorses preferred C. filiformis as holdfast. Adult seahorse density (individuals/m²) was significantly correlated with percentage vegetation cover and with holdfast length, but juvenile seahorse density was not. Nonetheless, significantly more adult and juvenile seahorses were found at sites characterized by high vegetation cover (>75%) than at sites with lower cover. Our results indicate that although there is some evidence that Knynsa seahorses prefer certain plant species over others, they are likely to be encountered anywhere in the estuary where aquatic plants are present. Conservation efforts in the Knysna Estuary should thus concentrate on such vegetated areas, which comprise approximately 11% of the total submerged surface area.
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Dog Latin, Norman Morrissey : book review
- Authors: Beard, Margot
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6115 , http://hdl.handle.net/10962/d1003828
- Description: I have only seen one earlier collection of Morrissey's - his slim volume Seasons (1999). Therein he revealed his enjoyment and interest in haiku. Even the two longer poems in that volume were haiku-like, being brief self-contained stanzas grouped under a single title. His new volume, Dog Latin, consists of sixty short poems primarily concerned with man and nature. A number of these are haiku-like in their brevity ("Edgar on Inclusive Fitness," "Setting Ratbane," "Adam Again"), although they too often do not amount to more than post-it like notes. ("This habit / of holding habits to the wind / -me" is the sum total of the poem "Adam Again.") The epigraph to the whole collection is the final stanza of Robert Frost's "The Need of Being Versed in Country Things," which suggests both Morrissey's interest in the apparently unconsidered minutiae of natural objects and beings, and, it would seem, an admiration of Frost's deceptively plain, unmannered style.
- Full Text:
- Authors: Beard, Margot
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6115 , http://hdl.handle.net/10962/d1003828
- Description: I have only seen one earlier collection of Morrissey's - his slim volume Seasons (1999). Therein he revealed his enjoyment and interest in haiku. Even the two longer poems in that volume were haiku-like, being brief self-contained stanzas grouped under a single title. His new volume, Dog Latin, consists of sixty short poems primarily concerned with man and nature. A number of these are haiku-like in their brevity ("Edgar on Inclusive Fitness," "Setting Ratbane," "Adam Again"), although they too often do not amount to more than post-it like notes. ("This habit / of holding habits to the wind / -me" is the sum total of the poem "Adam Again.") The epigraph to the whole collection is the final stanza of Robert Frost's "The Need of Being Versed in Country Things," which suggests both Morrissey's interest in the apparently unconsidered minutiae of natural objects and beings, and, it would seem, an admiration of Frost's deceptively plain, unmannered style.
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Editorial, 2007
- Lotz-Sisitka, Heila, O’Donoghue, Rob B, Robottom, Ian
- Authors: Lotz-Sisitka, Heila , O’Donoghue, Rob B , Robottom, Ian
- Date: 2007
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67345 , vital:29078 , https://www.ajol.info/index.php/sajee/article/view/122733
- Description: publisher version , The year 2007 is a significant year for environmental education. It marks 30 years since the first internationally agreed principles of environmental education were developed at Tbilisi, commonly known as the Tbilisi Principles. It is also the year in which human beings apparently are finally ‘waking up’ to the fact that human-induced environmental change is causing impacts which are infinitely complex and difficult to resolve. This year, through various highly publicised and politicised events, people have begun to recognise that it is getting hot on planet Earth, and that the associated social, economic and environmental costs are profoundly disturbing. The Stern Review and the UN Intergovernmental Panel on Climate Change both firmly indicated that human-induced environmental change will threaten human economies and security in ways that are unprecedented in human history.
- Full Text:
- Authors: Lotz-Sisitka, Heila , O’Donoghue, Rob B , Robottom, Ian
- Date: 2007
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67345 , vital:29078 , https://www.ajol.info/index.php/sajee/article/view/122733
- Description: publisher version , The year 2007 is a significant year for environmental education. It marks 30 years since the first internationally agreed principles of environmental education were developed at Tbilisi, commonly known as the Tbilisi Principles. It is also the year in which human beings apparently are finally ‘waking up’ to the fact that human-induced environmental change is causing impacts which are infinitely complex and difficult to resolve. This year, through various highly publicised and politicised events, people have begun to recognise that it is getting hot on planet Earth, and that the associated social, economic and environmental costs are profoundly disturbing. The Stern Review and the UN Intergovernmental Panel on Climate Change both firmly indicated that human-induced environmental change will threaten human economies and security in ways that are unprecedented in human history.
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Education decentralization in the Omaheke Region of Namibia
- Authors: Semba, Pecka
- Date: 2007
- Subjects: Education -- Namibia Schools -- Decentralization -- Namibia Education and state -- Namibia Educational change -- Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1894 , http://hdl.handle.net/10962/d1006114
- Description: Before the attainment of independence on 21 March 1990, the people of Namibia were engaged in a protracted struggle against colonialism, racism and apartheid, all of which had denied the majority of the people democracy and development. The people of Namibia therefore did not have power to make decisions on matters that affect their lives and were also not able to determine their own destiny (Ministry of Regional Government and Housing [MoRGH]: 1998:1). After independence, the Namibian government provided for a policy of decentralization under Chapter 12 of the Constitution. After adopting decentralization as state policy in 1996 the government, under the auspices of the Ministry of Regional, Local Government and Housing, embarked upon an implementation process that began in 2003. Education decentralization was included in this process. As my research investigated participants' experience of education decentralization in the Omaheke Region, I conducted an interpretive case study. I employed semi-structured interviews as my main data collection instrument. The quality of my research lies mostly in the authenticity of my thick descriptions where I rely to a large degree on a high ratio of participant to researcher voice. The study has revealed that there is a basic understanding of what education decentralization refers to. Education decentralization is also perceived to provide for the democratization of education through the active participation of all relevant stakeholders - parents, teachers, learners and civil servants - in the education process. However, although there is a basic understanding of what education decentralization entails, there is not necessarily acceptance. The study revealed that many people in Omaheke have reservations about the process of decentralizing education services. Some regard education decentralization as central government "dumping" its responsibility on the Regions. Furthermore, neither the Regional Council, the Regional Education Office, schools, communities nor parents have the capacity to cope with decentralization. The responsibility for overseeing the implementation of decentralization in the Region lies with the Omaheke Regional Council. Education as a decentralized function ought to resort directly under the Regional Council. However, the Regional Education office does not yet operate under the Regional Council. Instead the Education Director continues to report directly to the Permanent Secretary of the Ministry of Education in the capital. In this way an important decentralization structure, the Regional Council, is bypassed and rendered toothless. The data reveal that there is only partial evidence of psychological and structural readiness for education decentralization. Consequently there is little meaningful participation and therefore no sense of ownership among parents, teachers, learners, community-based organizations and political leaders.
- Full Text:
- Authors: Semba, Pecka
- Date: 2007
- Subjects: Education -- Namibia Schools -- Decentralization -- Namibia Education and state -- Namibia Educational change -- Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1894 , http://hdl.handle.net/10962/d1006114
- Description: Before the attainment of independence on 21 March 1990, the people of Namibia were engaged in a protracted struggle against colonialism, racism and apartheid, all of which had denied the majority of the people democracy and development. The people of Namibia therefore did not have power to make decisions on matters that affect their lives and were also not able to determine their own destiny (Ministry of Regional Government and Housing [MoRGH]: 1998:1). After independence, the Namibian government provided for a policy of decentralization under Chapter 12 of the Constitution. After adopting decentralization as state policy in 1996 the government, under the auspices of the Ministry of Regional, Local Government and Housing, embarked upon an implementation process that began in 2003. Education decentralization was included in this process. As my research investigated participants' experience of education decentralization in the Omaheke Region, I conducted an interpretive case study. I employed semi-structured interviews as my main data collection instrument. The quality of my research lies mostly in the authenticity of my thick descriptions where I rely to a large degree on a high ratio of participant to researcher voice. The study has revealed that there is a basic understanding of what education decentralization refers to. Education decentralization is also perceived to provide for the democratization of education through the active participation of all relevant stakeholders - parents, teachers, learners and civil servants - in the education process. However, although there is a basic understanding of what education decentralization entails, there is not necessarily acceptance. The study revealed that many people in Omaheke have reservations about the process of decentralizing education services. Some regard education decentralization as central government "dumping" its responsibility on the Regions. Furthermore, neither the Regional Council, the Regional Education Office, schools, communities nor parents have the capacity to cope with decentralization. The responsibility for overseeing the implementation of decentralization in the Region lies with the Omaheke Regional Council. Education as a decentralized function ought to resort directly under the Regional Council. However, the Regional Education office does not yet operate under the Regional Council. Instead the Education Director continues to report directly to the Permanent Secretary of the Ministry of Education in the capital. In this way an important decentralization structure, the Regional Council, is bypassed and rendered toothless. The data reveal that there is only partial evidence of psychological and structural readiness for education decentralization. Consequently there is little meaningful participation and therefore no sense of ownership among parents, teachers, learners, community-based organizations and political leaders.
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Education is a spring … it bubbles:
- Authors: Berger, Guy
- Date: 2007
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159288 , vital:40284 , https://hdl.handle.net/10520/EJC144678
- Description: Asians, Americans, Australians. A handful of Africans and a couple of Arabs. A sprinkling of Canadians, Mexicans, Finns. An Israeli, a Chilean and quite a few others. In total, 450 people from some 50 countries. In common: they're all lecturers and trainers. Busy swopping notes in Singapore at the first-ever World Journalism Education Congress (WJEC) in July. It's a resource-rich pool of ideas and experiences.
- Full Text:
- Authors: Berger, Guy
- Date: 2007
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159288 , vital:40284 , https://hdl.handle.net/10520/EJC144678
- Description: Asians, Americans, Australians. A handful of Africans and a couple of Arabs. A sprinkling of Canadians, Mexicans, Finns. An Israeli, a Chilean and quite a few others. In total, 450 people from some 50 countries. In common: they're all lecturers and trainers. Busy swopping notes in Singapore at the first-ever World Journalism Education Congress (WJEC) in July. It's a resource-rich pool of ideas and experiences.
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Effects of financial integration on financial development and economic performance of the SACU countries
- Authors: Aziakpono, Meshach J
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , conference paper
- Identifier: http://hdl.handle.net/10962/469944 , vital:77309 , ISBN
- Description: This paper examines the effects of financial integration on financial development and economic performance of the SACU countries within a country-specific framework. The paper employs four measures of financial integration, two measures of financial development and real per capita output and annual time series from 1970 to 2004 for the analysis. The econometric analyses were carried out using the Johansen cointegration and error correction modelling techniques. The effects of financial integration were mixed, but what is apparent is that countries that are more integrated to South Africa produce more discernible evidence of positive effects of financial integration. The paper attributes the weak gains from the official integration arrangement to weak institutional and structural impediments in the countries.
- Full Text:
- Authors: Aziakpono, Meshach J
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , conference paper
- Identifier: http://hdl.handle.net/10962/469944 , vital:77309 , ISBN
- Description: This paper examines the effects of financial integration on financial development and economic performance of the SACU countries within a country-specific framework. The paper employs four measures of financial integration, two measures of financial development and real per capita output and annual time series from 1970 to 2004 for the analysis. The econometric analyses were carried out using the Johansen cointegration and error correction modelling techniques. The effects of financial integration were mixed, but what is apparent is that countries that are more integrated to South Africa produce more discernible evidence of positive effects of financial integration. The paper attributes the weak gains from the official integration arrangement to weak institutional and structural impediments in the countries.
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Effects of substituents on the photochemical and photophysical properties of main group metal phthalocyanines
- Authors: Nyokong, Tebello
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6581 , http://hdl.handle.net/10962/d1004146
- Description: The review focuses on the photochemical (singlet oxygen and photobleaching quantum yields) and photophysical (triplet quantum yields and lifetimes and fluorescence lifetimes) properties of metallophthalocyanine complexes containing main group metals (Zn, Al, Ge, Si, Sn, Ga and In) and some unmetallated phthalocyanine complexes. Five tables containing photophysical and photochemical data for sulfonated phthalocyanines, tetra-, octa-substituted and unsubstituted phthalocyanines in a variety of solvents, are included in the review.
- Full Text:
- Authors: Nyokong, Tebello
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6581 , http://hdl.handle.net/10962/d1004146
- Description: The review focuses on the photochemical (singlet oxygen and photobleaching quantum yields) and photophysical (triplet quantum yields and lifetimes and fluorescence lifetimes) properties of metallophthalocyanine complexes containing main group metals (Zn, Al, Ge, Si, Sn, Ga and In) and some unmetallated phthalocyanine complexes. Five tables containing photophysical and photochemical data for sulfonated phthalocyanines, tetra-, octa-substituted and unsubstituted phthalocyanines in a variety of solvents, are included in the review.
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Electroanalysis of thiocyanate using a novel glassy carbon electrode modified by aryl radicals and cobalt tetracarboxyphthalocyanine
- Matemadombo, Fungisai, Westbroek, Philippe, Nyokong, Tebello
- Authors: Matemadombo, Fungisai , Westbroek, Philippe , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/268750 , vital:54228 , xlink:href="https://doi.org/10.1016/j.electacta.2007.06.064"
- Description: Electrochemical grafting of 4-nitrobenzenediazonium tetrafluoroborate onto a glassy carbon electrode (GCE) results in the formation of a nitrophenyl radical, which reacts with the surface to form a covalent bond (grafting) and results in a nitrophenyl modified electrode. The nitro group is electrochemically reduced to a NH2 group. Cobalt tetracarboxyphthalocyanine (CoTCPc) complex is then attached to the NH2 group using 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC) and N-hydroxysuccinimide (NHS) as coupling agents. The new CoTCPc modified electrode was characterized using cyclic voltammetry and then employed for the catalytic oxidation of thiocyanate.
- Full Text:
- Authors: Matemadombo, Fungisai , Westbroek, Philippe , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/268750 , vital:54228 , xlink:href="https://doi.org/10.1016/j.electacta.2007.06.064"
- Description: Electrochemical grafting of 4-nitrobenzenediazonium tetrafluoroborate onto a glassy carbon electrode (GCE) results in the formation of a nitrophenyl radical, which reacts with the surface to form a covalent bond (grafting) and results in a nitrophenyl modified electrode. The nitro group is electrochemically reduced to a NH2 group. Cobalt tetracarboxyphthalocyanine (CoTCPc) complex is then attached to the NH2 group using 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC) and N-hydroxysuccinimide (NHS) as coupling agents. The new CoTCPc modified electrode was characterized using cyclic voltammetry and then employed for the catalytic oxidation of thiocyanate.
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Electrocatalytic activity of arylthio tetra-substituted oxotitanium (IV) phthalocyanines towards the oxidation of nitrite
- Tau, Prudence, Nyokong, Tebello
- Authors: Tau, Prudence , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/281234 , vital:55704 , xlink:href="https://doi.org/10.1016/j.electacta.2006.12.059"
- Description: This paper investigates the catalytic activities of arylthio substituted oxotitanium phthalocyanine (OTiPc) complexes that are immobilized on the glassy carbon electrode by electropolymerization, towards the oxidation of nitrite. The complexes are peripherally and non-peripherally substituted with phenylthio and benzylthio groups, namely 1a, 1b, 2a and 2b. All the modified electrodes exhibited improved electrocatalytic oxidation of nitrite than the unmodified electrodes by a two-electron mechanism producing nitrate ions. Catalytic currents are enhanced and nitrite overpotential reduced to ∼0.60 V. Kinetic parameters are determined for all complexes and a mechanism is proposed.
- Full Text:
- Authors: Tau, Prudence , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/281234 , vital:55704 , xlink:href="https://doi.org/10.1016/j.electacta.2006.12.059"
- Description: This paper investigates the catalytic activities of arylthio substituted oxotitanium phthalocyanine (OTiPc) complexes that are immobilized on the glassy carbon electrode by electropolymerization, towards the oxidation of nitrite. The complexes are peripherally and non-peripherally substituted with phenylthio and benzylthio groups, namely 1a, 1b, 2a and 2b. All the modified electrodes exhibited improved electrocatalytic oxidation of nitrite than the unmodified electrodes by a two-electron mechanism producing nitrate ions. Catalytic currents are enhanced and nitrite overpotential reduced to ∼0.60 V. Kinetic parameters are determined for all complexes and a mechanism is proposed.
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Electrocatalytic oxidation of chlorophenols by electropolymerised nickel (II) tetrakis benzylmercapto and dodecylmercapto metallophthalocyanines complexes on gold electrodes
- Agboola, Bolade, Nyokong, Tebello
- Authors: Agboola, Bolade , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/281247 , vital:55705 , xlink:href="https://doi.org/10.1016/j.electacta.2007.02.017"
- Description: This work reports on the use of nickel(II) tetrakis benzylmercapto (NiTBMPc) and dodecylmercapto (NiTDMPc) metallophthalocyanine complexes films on gold electrodes for the electrochemical oxidation of 4-chlorophenol (4-CP) and 2,4,5-trichlorophenol (TCP). Both NiTBMPc and NiTDMPc complexes were successfully deposited on gold electrodes by electropolymerisation. The films were electro-transformed in aqueous 0.1 M NaOH solution to the ‘O–Ni–O oxo’ bridged form. For both complexes, films with different thickness were prepared and characterised by electrochemical impedance and UV–vis (on indium tin oxide) spectroscopies and the results showed typical behaviour for modified electrodes with increasing charge transfer resistance values (Rp) with polymer thickness. The poly-Ni(OH)NiPcs showed better catalytic activity than their poly-NiPcs counterparts.
- Full Text:
- Authors: Agboola, Bolade , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/281247 , vital:55705 , xlink:href="https://doi.org/10.1016/j.electacta.2007.02.017"
- Description: This work reports on the use of nickel(II) tetrakis benzylmercapto (NiTBMPc) and dodecylmercapto (NiTDMPc) metallophthalocyanine complexes films on gold electrodes for the electrochemical oxidation of 4-chlorophenol (4-CP) and 2,4,5-trichlorophenol (TCP). Both NiTBMPc and NiTDMPc complexes were successfully deposited on gold electrodes by electropolymerisation. The films were electro-transformed in aqueous 0.1 M NaOH solution to the ‘O–Ni–O oxo’ bridged form. For both complexes, films with different thickness were prepared and characterised by electrochemical impedance and UV–vis (on indium tin oxide) spectroscopies and the results showed typical behaviour for modified electrodes with increasing charge transfer resistance values (Rp) with polymer thickness. The poly-Ni(OH)NiPcs showed better catalytic activity than their poly-NiPcs counterparts.
- Full Text:
Electrocatalytic oxidation of nitrite by tetra-substituted oxotitanium (IV) phthalocyanines adsorbed or polymerised on glassy carbon electrode
- Tau, Prudence, Nyokong, Tebello
- Authors: Tau, Prudence , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/268762 , vital:54230 , xlink:href="https://doi.org/10.1016/j.jelechem.2007.07.019"
- Description: Comparative electrocatalytic oxidation of nitrite by tetra aryloxy-substituted oxotitanium(IV) and tetraamino phthalocyanine complexes is investigated in this work. The aryloxy complexes are substituted at the peripheral (4) and non-peripheral (5) positions with phenoxy (complexes a), 4-tert-butylphenoxy (complexes b), benzyloxy (complexes c) and 4-(benzyloxy)phenoxy (complexes d) groups. The glassy carbon electrode was employed and modified with the tetra aryloxy-substituted titanium phthalocyanine complexes (4 and 5) by adsorption, and with titanium tetraamino phthalocyanine (TiTAPc) by polymerisation. All complexes reduced the overpotential of the nitrite electrooxidation as well as enhanced the catalytic current by a 2 electron process.
- Full Text:
- Authors: Tau, Prudence , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/268762 , vital:54230 , xlink:href="https://doi.org/10.1016/j.jelechem.2007.07.019"
- Description: Comparative electrocatalytic oxidation of nitrite by tetra aryloxy-substituted oxotitanium(IV) and tetraamino phthalocyanine complexes is investigated in this work. The aryloxy complexes are substituted at the peripheral (4) and non-peripheral (5) positions with phenoxy (complexes a), 4-tert-butylphenoxy (complexes b), benzyloxy (complexes c) and 4-(benzyloxy)phenoxy (complexes d) groups. The glassy carbon electrode was employed and modified with the tetra aryloxy-substituted titanium phthalocyanine complexes (4 and 5) by adsorption, and with titanium tetraamino phthalocyanine (TiTAPc) by polymerisation. All complexes reduced the overpotential of the nitrite electrooxidation as well as enhanced the catalytic current by a 2 electron process.
- Full Text: