Spotlight on research: 50 years of Pharmaceutical Sciences Research Excellence Faculty of Pharmacy Rhodes University
- Authors: Walker, Roderick B
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184243 , vital:44193 , xlink:href="https://hdl.handle.net/10520/EJC81478"
- Description: This year, the Faculty of Pharmacy at Rhodes University is celebrating its 50th Anniversary. Over 2000 BPharm, 33 BSc honours, 65 MSc and 27 PhD degrees have been conferred since the Faculty’s inception. The diverse research activities and dedicated academic staff have ensured that the Faculty of Pharmacy has high visibility with respect to research outputs, as is evidenced by the appointment of various members of staff to national and international research, regulatory and professional committees, as well as to serving on the editorial boards of a number of international journals. In addition, staff regularly publish in international and local peer-reviewed journals and present their research findings at international and local conferences.
- Full Text:
- Date Issued: 2006
- Authors: Walker, Roderick B
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184243 , vital:44193 , xlink:href="https://hdl.handle.net/10520/EJC81478"
- Description: This year, the Faculty of Pharmacy at Rhodes University is celebrating its 50th Anniversary. Over 2000 BPharm, 33 BSc honours, 65 MSc and 27 PhD degrees have been conferred since the Faculty’s inception. The diverse research activities and dedicated academic staff have ensured that the Faculty of Pharmacy has high visibility with respect to research outputs, as is evidenced by the appointment of various members of staff to national and international research, regulatory and professional committees, as well as to serving on the editorial boards of a number of international journals. In addition, staff regularly publish in international and local peer-reviewed journals and present their research findings at international and local conferences.
- Full Text:
- Date Issued: 2006
Synthesis and electrochemical characterisation of α-and β-tetra-substituted oxo (phthalocyaninato) titanium (IV) complexes
- Tau, Prudence, Nyokong, Tebello
- Authors: Tau, Prudence , Nyokong, Tebello
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/283869 , vital:55998 , xlink:href="https://doi.org/10.1016/j.poly.2005.11.025"
- Description: The synthesis, spectroscopic and electrochemical characterisation of the following oxotitanium tetra-substituted phthalocyanines are reported: 1,(4)-(tetraphenoxyphthalocyaninato)titanium(IV) oxide (5a); 1,(4)-(tetra-tert-butylphenoxyphthalocyaninato)titanium(IV) oxide (5b); 2,(3)-(tetraphenoxyphthalocyaninato)titanium(IV) oxide (6a) and 2,(3)-(tetra-tert-butylphenoxyphthalocyaninato)titanium(IV) oxide (6b). Complexes 5a and 5b are substituted at the non-peripheral (α) positions, whereas complexes 6a and 6b are substituted at the peripheral (β) positions. Cyclic voltammograms of all four complexes are similar, with three reversible reduction couples and three quasi-reversible to irreversible oxidations. The first two reductions are two-electron processes, confirmed by spectroelectrochemistry to be due to TiIVPc−2/TiIIPc−3 and TiIIPc−2/TiIPc−3 redox processes. Spectroelectrochemistry showed that upon oxidation, the molecule decomposes. Oxidation is expected to occur at the ring. Chronocoulometry confirmed two electron transfer at the first and second reduction steps; and a one electron transfer at the third reduction.
- Full Text:
- Date Issued: 2006
- Authors: Tau, Prudence , Nyokong, Tebello
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/283869 , vital:55998 , xlink:href="https://doi.org/10.1016/j.poly.2005.11.025"
- Description: The synthesis, spectroscopic and electrochemical characterisation of the following oxotitanium tetra-substituted phthalocyanines are reported: 1,(4)-(tetraphenoxyphthalocyaninato)titanium(IV) oxide (5a); 1,(4)-(tetra-tert-butylphenoxyphthalocyaninato)titanium(IV) oxide (5b); 2,(3)-(tetraphenoxyphthalocyaninato)titanium(IV) oxide (6a) and 2,(3)-(tetra-tert-butylphenoxyphthalocyaninato)titanium(IV) oxide (6b). Complexes 5a and 5b are substituted at the non-peripheral (α) positions, whereas complexes 6a and 6b are substituted at the peripheral (β) positions. Cyclic voltammograms of all four complexes are similar, with three reversible reduction couples and three quasi-reversible to irreversible oxidations. The first two reductions are two-electron processes, confirmed by spectroelectrochemistry to be due to TiIVPc−2/TiIIPc−3 and TiIIPc−2/TiIPc−3 redox processes. Spectroelectrochemistry showed that upon oxidation, the molecule decomposes. Oxidation is expected to occur at the ring. Chronocoulometry confirmed two electron transfer at the first and second reduction steps; and a one electron transfer at the third reduction.
- Full Text:
- Date Issued: 2006
Synthesis and photophysical properties of octa-substituted phthalocyaninato oxotitanium (IV) derivatives
- Tau, Prudence, Nyokong, Tebello
- Authors: Tau, Prudence , Nyokong, Tebello
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/283881 , vital:55999 , xlink:href="https://doi.org/10.1142/S1088424606000399"
- Description: The synthesis, spectral and photophysical properties including fluorescence quenching of the following octa-substituted oxotitanium phthalocyanines are reported: 2,3,9,10,16,17,23,24-octaphenoxyphthalocyaninato titanium(IV) oxide, 2,3,9,10,16,17,23,24-[octakis(4-t-butylphenoxyphthalocyaninato)]titanium(IV) oxide, 2,3,9,10,16,17,23,24-{octakis[(4-benzyloxy)phenoxy]phthalocyaninato}titanium(IV) oxide and 2,3,9,10,16,17,23,24-octaphenylthiophthalocyaninato titanium(IV) oxide. The complexes are characterized by 1H NMR, IR and UV-vis spectroscopies. Their photophysical properties are presented where moderate fluorescence quantum yields (0.14-0.19) and lifetimes were determined. Varied triplet quantum yields were obtained and the triplet lifetimes (40-100 μs) were short.
- Full Text:
- Date Issued: 2006
- Authors: Tau, Prudence , Nyokong, Tebello
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/283881 , vital:55999 , xlink:href="https://doi.org/10.1142/S1088424606000399"
- Description: The synthesis, spectral and photophysical properties including fluorescence quenching of the following octa-substituted oxotitanium phthalocyanines are reported: 2,3,9,10,16,17,23,24-octaphenoxyphthalocyaninato titanium(IV) oxide, 2,3,9,10,16,17,23,24-[octakis(4-t-butylphenoxyphthalocyaninato)]titanium(IV) oxide, 2,3,9,10,16,17,23,24-{octakis[(4-benzyloxy)phenoxy]phthalocyaninato}titanium(IV) oxide and 2,3,9,10,16,17,23,24-octaphenylthiophthalocyaninato titanium(IV) oxide. The complexes are characterized by 1H NMR, IR and UV-vis spectroscopies. Their photophysical properties are presented where moderate fluorescence quantum yields (0.14-0.19) and lifetimes were determined. Varied triplet quantum yields were obtained and the triplet lifetimes (40-100 μs) were short.
- Full Text:
- Date Issued: 2006
Teacher-community cooperation to promote sustainability of wetlands in Kenya
- Ndaruga, Ayub M, Irwin, Patrick R
- Authors: Ndaruga, Ayub M , Irwin, Patrick R
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/373860 , vital:66728 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122727"
- Description: This study was undertaken with 83 teachers from 54 primary schools in Kenya. Its purpose was to establish how teachers relate with the local community and how they harness this interaction to promote sustainability of wetlands within their locality. Data were collected using questionnaires, interviews and observation. Results of the study indicated that teachers acknowledge the value of, and threats to, their local wetlands. Some teachers reported interacting and engaging in diverse activities with members of the community to conserve the local wetlands. Forums for interaction and action mentioned by the teachers included public baraza, women’s groups, church, youth groups, local community, parents’ meetings and environmental days. Use of these forums differed. The approaches used to involve the community in awareness and action ranged from theoretical arguments to visits to wetlands, use of wetland resources, ecomanagement and political action. The responses by teachers revealed lack of engagement with the real local wetland problems. This study demonstrated existence of a potential but under-utilised opportunity that can be harnessed by environmental education programmes to champion the sustainability of wetlands.
- Full Text:
- Date Issued: 2006
- Authors: Ndaruga, Ayub M , Irwin, Patrick R
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/373860 , vital:66728 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122727"
- Description: This study was undertaken with 83 teachers from 54 primary schools in Kenya. Its purpose was to establish how teachers relate with the local community and how they harness this interaction to promote sustainability of wetlands within their locality. Data were collected using questionnaires, interviews and observation. Results of the study indicated that teachers acknowledge the value of, and threats to, their local wetlands. Some teachers reported interacting and engaging in diverse activities with members of the community to conserve the local wetlands. Forums for interaction and action mentioned by the teachers included public baraza, women’s groups, church, youth groups, local community, parents’ meetings and environmental days. Use of these forums differed. The approaches used to involve the community in awareness and action ranged from theoretical arguments to visits to wetlands, use of wetland resources, ecomanagement and political action. The responses by teachers revealed lack of engagement with the real local wetland problems. This study demonstrated existence of a potential but under-utilised opportunity that can be harnessed by environmental education programmes to champion the sustainability of wetlands.
- Full Text:
- Date Issued: 2006
The Condictio Indebiti and Unjust Factors (1)
- Authors: Glover, Graham B
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186869 , vital:44541 , xlink:href="file:///C:/Users/User/Downloads/69THRHR419%20(2).pdf"
- Description: Since the Supreme Court of Appeal has continued to avoid taking the step of recognising a general enrichment action,' the traditional enrichment actions of the common law remain fundamentally important to the operation of the law of unjustified enrichment in South Africa. Most significant of these is the condictio indebiti, which is probably the most well-known and liberally utilised enrichment action in South African law.2 In this article, the nature and scope of this condictio will be examined, and it will be shown that it has grown beyond its notionally traditional role of reversing payments or transfers made unjustifiably by mistake, to include causes of action in duress and protest. The implications of this for the condictio, as well as for the foundations of our enrichment law will then be examined, with reference to the two leading schools of enrichment law: the civilian school, typified by German law, and the common-law school, typified by English law.
- Full Text:
- Date Issued: 2006
- Authors: Glover, Graham B
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186869 , vital:44541 , xlink:href="file:///C:/Users/User/Downloads/69THRHR419%20(2).pdf"
- Description: Since the Supreme Court of Appeal has continued to avoid taking the step of recognising a general enrichment action,' the traditional enrichment actions of the common law remain fundamentally important to the operation of the law of unjustified enrichment in South Africa. Most significant of these is the condictio indebiti, which is probably the most well-known and liberally utilised enrichment action in South African law.2 In this article, the nature and scope of this condictio will be examined, and it will be shown that it has grown beyond its notionally traditional role of reversing payments or transfers made unjustifiably by mistake, to include causes of action in duress and protest. The implications of this for the condictio, as well as for the foundations of our enrichment law will then be examined, with reference to the two leading schools of enrichment law: the civilian school, typified by German law, and the common-law school, typified by English law.
- Full Text:
- Date Issued: 2006
The Condictio Indebiti and Unjust Factors (2)
- Authors: Glover, Graham B
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186880 , vital:44544 , xlink:href="///C:/Users/User/Downloads/69THRHR561%20(1).pdf"
- Description: Since the Supreme Court of Appeal has continued to avoid taking the step of recognising a general enrichment action,' the traditional enrichment actions of the common law remain fundamentally important to the operation of the law of unjustified enrichment in South Africa. Most significant of these is the condictio indebiti, which is probably the most well-known and liberally utilised enrichment action in South African law.2 In this article, the nature and scope of this condictio will be examined, and it will be shown that it has grown beyond its notionally traditional role of reversing payments or transfers made unjustifiably by mistake, to include causes of action in duress and protest. The implications of this for the condictio, as well as for the foundations of our enrichment law will then be examined, with reference to the two leading schools of enrichment law: the civilian school, typified by German law, and the common-law school, typified by English law.
- Full Text:
- Date Issued: 2006
- Authors: Glover, Graham B
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186880 , vital:44544 , xlink:href="///C:/Users/User/Downloads/69THRHR561%20(1).pdf"
- Description: Since the Supreme Court of Appeal has continued to avoid taking the step of recognising a general enrichment action,' the traditional enrichment actions of the common law remain fundamentally important to the operation of the law of unjustified enrichment in South Africa. Most significant of these is the condictio indebiti, which is probably the most well-known and liberally utilised enrichment action in South African law.2 In this article, the nature and scope of this condictio will be examined, and it will be shown that it has grown beyond its notionally traditional role of reversing payments or transfers made unjustifiably by mistake, to include causes of action in duress and protest. The implications of this for the condictio, as well as for the foundations of our enrichment law will then be examined, with reference to the two leading schools of enrichment law: the civilian school, typified by German law, and the common-law school, typified by English law.
- Full Text:
- Date Issued: 2006
The effect of Ge, Si and Sn phthalocyanine photosensitizers on cell proliferation and viability of human oesophageal carcinoma cells
- Seotsanyana-Mokhosi, Itumeleng, Kresfelder, Tina, Abrahamse, Heidi, Nyokong, Tebello
- Authors: Seotsanyana-Mokhosi, Itumeleng , Kresfelder, Tina , Abrahamse, Heidi , Nyokong, Tebello
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/286115 , vital:56241 , xlink:href="https://doi.org/10.1016/j.jphotobiol.2005.12.004"
- Description: The photodynamic activity of water soluble mixed sulfonated metallophthalocyanines complexes: GePcSmix, SnPcSmix and SiPcSmix on human oesophageal carcinoma (SNO) cells are reported, and compared with the activity of the unmetallated H2PcSmix and of the newly synthesized water soluble adjacently substituted binaphthalo phthalocyanine (complex 3). The alkaline phosphate (ALP) showed damage to the cell membrane in the presence of complex 3 without irradiation. The GePcSmix complex caused a relatively large increase in inflammation and a high intracellular ATP.
- Full Text:
- Date Issued: 2006
- Authors: Seotsanyana-Mokhosi, Itumeleng , Kresfelder, Tina , Abrahamse, Heidi , Nyokong, Tebello
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/286115 , vital:56241 , xlink:href="https://doi.org/10.1016/j.jphotobiol.2005.12.004"
- Description: The photodynamic activity of water soluble mixed sulfonated metallophthalocyanines complexes: GePcSmix, SnPcSmix and SiPcSmix on human oesophageal carcinoma (SNO) cells are reported, and compared with the activity of the unmetallated H2PcSmix and of the newly synthesized water soluble adjacently substituted binaphthalo phthalocyanine (complex 3). The alkaline phosphate (ALP) showed damage to the cell membrane in the presence of complex 3 without irradiation. The GePcSmix complex caused a relatively large increase in inflammation and a high intracellular ATP.
- Full Text:
- Date Issued: 2006
The sharing of pension benefits on divorce: An inevitable affair?
- Authors: Glover, Graham B
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186723 , vital:44528 , xlink:href="Print only"
- Description: One of the invariable consequences of divorce is that the patrimonial assets of the marriage have to be divided up between the two parties. At a primary level, the way in which this will occur will be determined by a number of factors: the matrimonial property regime under which the parties had been married; the relevant provisions of the Divorce Act (Act 70 of 1979) that deal with the question of the patrimonial consequences of divorce; as well as any agreement on this often ticklish matter that can be reached by the parties prior to the divorce action. Approximately fourteen years ago, section 7 of the Divorce Act was amended to allow a divorced spouse to share in the pension interests of the other spouse. There is some polemic, though, as to the interpretation of this provision: in particular, it is not clear whether this pension benefit will automatically form part of the assets that are susceptible to division, or whether a prayer to this effect must specifically be sought. After a consideration of the current legal position regarding the sharing of pension benefits generally, this note will examine this specific debate.
- Full Text:
- Date Issued: 2006
- Authors: Glover, Graham B
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186723 , vital:44528 , xlink:href="Print only"
- Description: One of the invariable consequences of divorce is that the patrimonial assets of the marriage have to be divided up between the two parties. At a primary level, the way in which this will occur will be determined by a number of factors: the matrimonial property regime under which the parties had been married; the relevant provisions of the Divorce Act (Act 70 of 1979) that deal with the question of the patrimonial consequences of divorce; as well as any agreement on this often ticklish matter that can be reached by the parties prior to the divorce action. Approximately fourteen years ago, section 7 of the Divorce Act was amended to allow a divorced spouse to share in the pension interests of the other spouse. There is some polemic, though, as to the interpretation of this provision: in particular, it is not clear whether this pension benefit will automatically form part of the assets that are susceptible to division, or whether a prayer to this effect must specifically be sought. After a consideration of the current legal position regarding the sharing of pension benefits generally, this note will examine this specific debate.
- Full Text:
- Date Issued: 2006
Trade in reed-based craft products in rural villages in the Eastern Cape, South Africa
- Pereira, Taryn, Shackleton, Charlie M, Shackleton, Sheona E
- Authors: Pereira, Taryn , Shackleton, Charlie M , Shackleton, Sheona E
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181290 , vital:43716 , xlink:href="https://doi.org/10.1080/03768350600927235"
- Description: Selling traditional craft products made from fibrous plants is an important source of income for economically vulnerable rural women. In the Eastern Cape Province of South Africa, Cyperus textilis and Juncus kraussii have been used for centuries to make products of functional and cultural importance, such as sleeping mats and baskets. In the former Transkei village clusters of Mpozolo and Ntubeni, female crafters harvest the raw material and make and sell the products in their communities and in nearby towns. Interviews with 40 of them revealed what the trade contributes to their livelihoods and what enhances or limits their success. The findings show that crafting contributes vital income to vulnerable households, on average 26 ± 4 per cent of annual household cash income, over 40 per cent for the poorest households and 5–15 per cent for wealthier households. Lack of access to non-traditional markets was identified as the main constraint on the trade.
- Full Text:
- Date Issued: 2006
- Authors: Pereira, Taryn , Shackleton, Charlie M , Shackleton, Sheona E
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181290 , vital:43716 , xlink:href="https://doi.org/10.1080/03768350600927235"
- Description: Selling traditional craft products made from fibrous plants is an important source of income for economically vulnerable rural women. In the Eastern Cape Province of South Africa, Cyperus textilis and Juncus kraussii have been used for centuries to make products of functional and cultural importance, such as sleeping mats and baskets. In the former Transkei village clusters of Mpozolo and Ntubeni, female crafters harvest the raw material and make and sell the products in their communities and in nearby towns. Interviews with 40 of them revealed what the trade contributes to their livelihoods and what enhances or limits their success. The findings show that crafting contributes vital income to vulnerable households, on average 26 ± 4 per cent of annual household cash income, over 40 per cent for the poorest households and 5–15 per cent for wealthier households. Lack of access to non-traditional markets was identified as the main constraint on the trade.
- Full Text:
- Date Issued: 2006
Unique electrochemical behavior of tantalum (V) phthalocyanine
- Tau, Prudence, Nyokong, Tebello
- Authors: Tau, Prudence , Nyokong, Tebello
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/286139 , vital:56243 , xlink:href="https://doi.org/10.1142/S1088424606000090"
- Description: The electrochemical and spectroscopic behavior of tantalum(V) phthalocyanine are presented. The NMR spectra is consistent with the lack of symmetry of the complex. Cyclic (CV) and square wave (SWV) voltammetries, and spectroelectrochemistry, were employed in the study of the complex. Two one-electron reductions and a simultaneous 4-electron reduction were observed. Reduction occurs first at the metal to form a Ta(IV) species, followed by ring based processes.
- Full Text:
- Date Issued: 2006
- Authors: Tau, Prudence , Nyokong, Tebello
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/286139 , vital:56243 , xlink:href="https://doi.org/10.1142/S1088424606000090"
- Description: The electrochemical and spectroscopic behavior of tantalum(V) phthalocyanine are presented. The NMR spectra is consistent with the lack of symmetry of the complex. Cyclic (CV) and square wave (SWV) voltammetries, and spectroelectrochemistry, were employed in the study of the complex. Two one-electron reductions and a simultaneous 4-electron reduction were observed. Reduction occurs first at the metal to form a Ta(IV) species, followed by ring based processes.
- Full Text:
- Date Issued: 2006
Urban forestry–A cinderella science in South Africa?
- Authors: Shackleton, Charlie M
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183092 , vital:43911 , xlink:href="https://doi.org/10.2989/10295920609505255"
- Description: The benefits of forests (in their broadest sense) and of trees to the natural environment and rural communities are well known throughout the world, including in South Africa (e.g. see chapters in Lawes et al. 2004). The presence of these benefits has also been extrapolated to urban situations, where natural forests and veld might be left in situ, or trees planted in public spaces, or in private gardens. These benefits span the social, aesthetic, health, environmental and economic spheres.
- Full Text:
- Date Issued: 2006
- Authors: Shackleton, Charlie M
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183092 , vital:43911 , xlink:href="https://doi.org/10.2989/10295920609505255"
- Description: The benefits of forests (in their broadest sense) and of trees to the natural environment and rural communities are well known throughout the world, including in South Africa (e.g. see chapters in Lawes et al. 2004). The presence of these benefits has also been extrapolated to urban situations, where natural forests and veld might be left in situ, or trees planted in public spaces, or in private gardens. These benefits span the social, aesthetic, health, environmental and economic spheres.
- Full Text:
- Date Issued: 2006
Urban fuelwood demand and markets in a small town in South Africa: Livelihood vulnerability and alien plant control
- Shackleton, Charlie M, McConnachie, Matthew M, Chauke, Maphambe I, Mentz, J, Sutherland, F, Gambiza, James, Jones, R
- Authors: Shackleton, Charlie M , McConnachie, Matthew M , Chauke, Maphambe I , Mentz, J , Sutherland, F , Gambiza, James , Jones, R
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181224 , vital:43710 , xlink:href="https://doi.org/10.1080/13504500609469697"
- Description: Fuelwood is the primary energy for most households throughout the developing world. With increasing urbanization and declining local availability of fuelwood, a growing proportion of households obtain their fuelwood by purchasing it. These fuelwood markets are the key nexus in supply and demand scenarios and can be potentially significant points for intervention to address energy security amongst the urban poor. This paper reports on the fuelwood demand and marketing in a small town in South Africa. Despite the availability of more modern fuels and state subsidization of electricity, fuelwood was still used by half the households. Annual demand was 1.2 t per household. Over half of the households bought their fuelwood requirements because local stocks were limited. Those households that did collect their own fuelwood were significantly poorer than households that purchased fuelwood, as well as households that did not use fuelwood at all. Fuelwood markets operated through 45-60 vendors who transported fuelwood from further afield. Income from the fuelwood trade was low, but was strongly linked to hours worked. Thus, vendors working a full week did earn a meaningful income, especially in the context of high unemployment in the area. Fuelwood vendors also provided casual employment opportunities for unskilled labour. Most vendors harvested fuelwood from commonage lands, with most of the wood being from alien species. Local stocks of wood are declining in the face of constant transformation of commonage to residential areas, and a national water and biodiversity conservation programme to eradicate alien plants. This decline poses a threat to the financial viability of fuelwood markets. Yet, an opportunity exists to incorporate the vendors into the alien plant clearing programme, since they already perform such a function.
- Full Text:
- Date Issued: 2006
- Authors: Shackleton, Charlie M , McConnachie, Matthew M , Chauke, Maphambe I , Mentz, J , Sutherland, F , Gambiza, James , Jones, R
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181224 , vital:43710 , xlink:href="https://doi.org/10.1080/13504500609469697"
- Description: Fuelwood is the primary energy for most households throughout the developing world. With increasing urbanization and declining local availability of fuelwood, a growing proportion of households obtain their fuelwood by purchasing it. These fuelwood markets are the key nexus in supply and demand scenarios and can be potentially significant points for intervention to address energy security amongst the urban poor. This paper reports on the fuelwood demand and marketing in a small town in South Africa. Despite the availability of more modern fuels and state subsidization of electricity, fuelwood was still used by half the households. Annual demand was 1.2 t per household. Over half of the households bought their fuelwood requirements because local stocks were limited. Those households that did collect their own fuelwood were significantly poorer than households that purchased fuelwood, as well as households that did not use fuelwood at all. Fuelwood markets operated through 45-60 vendors who transported fuelwood from further afield. Income from the fuelwood trade was low, but was strongly linked to hours worked. Thus, vendors working a full week did earn a meaningful income, especially in the context of high unemployment in the area. Fuelwood vendors also provided casual employment opportunities for unskilled labour. Most vendors harvested fuelwood from commonage lands, with most of the wood being from alien species. Local stocks of wood are declining in the face of constant transformation of commonage to residential areas, and a national water and biodiversity conservation programme to eradicate alien plants. This decline poses a threat to the financial viability of fuelwood markets. Yet, an opportunity exists to incorporate the vendors into the alien plant clearing programme, since they already perform such a function.
- Full Text:
- Date Issued: 2006
UV-Visible and Electrochemical Monitoring of Carbon Monoxide Release by Donor Complexes to Myoglobin Solutions and to Electrodes Modified with Films Containing Hemin
- Obirai, Joseph C, Hamadi, Sara, Ithurbide, Aurélie, Wartelle, Corinne, Nyokong, Tebello, Zagal, José, Top, Siden, Bedioui, Fethi
- Authors: Obirai, Joseph C , Hamadi, Sara , Ithurbide, Aurélie , Wartelle, Corinne , Nyokong, Tebello , Zagal, José , Top, Siden , Bedioui, Fethi
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/283906 , vital:56001 , xlink:href="https://doi.org/10.1002/elan.200603571"
- Description: This study reports on the evaluation of the CO donating behavior of tricarbonyl dichloro ruthenium(II) dimer ([Ru(CO)3Cl2]2) and 1,3-dimethoxyphenyl tricarbonyl chromium (C6H3(MeO)2Cr(CO)3) complex by UV-visible technique and electrochemical technique. The CO release was monitored by following the modifications of the UV-visible features of MbFe(II) in phosphate buffer solution and the redox features of reduced Hemin, HmFe(II), confined at the surface of a vitreous carbon electrode. In the latter case, the interaction between the hemin-modified electrode and the released CO was seen through the observation of an increase of the reduction current related to the FeIII/FeII redox process of the immobilized porphyrin. While the ruthenium-based complex, ([Ru(CO)3Cl2]2), depended on the presence of Fe(II) species to release CO, it was found that the chromium-based complex released spontaneously CO. This was facilitated by illuminating and/or simple stirring of the solution containing the complex.
- Full Text:
- Date Issued: 2006
- Authors: Obirai, Joseph C , Hamadi, Sara , Ithurbide, Aurélie , Wartelle, Corinne , Nyokong, Tebello , Zagal, José , Top, Siden , Bedioui, Fethi
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/283906 , vital:56001 , xlink:href="https://doi.org/10.1002/elan.200603571"
- Description: This study reports on the evaluation of the CO donating behavior of tricarbonyl dichloro ruthenium(II) dimer ([Ru(CO)3Cl2]2) and 1,3-dimethoxyphenyl tricarbonyl chromium (C6H3(MeO)2Cr(CO)3) complex by UV-visible technique and electrochemical technique. The CO release was monitored by following the modifications of the UV-visible features of MbFe(II) in phosphate buffer solution and the redox features of reduced Hemin, HmFe(II), confined at the surface of a vitreous carbon electrode. In the latter case, the interaction between the hemin-modified electrode and the released CO was seen through the observation of an increase of the reduction current related to the FeIII/FeII redox process of the immobilized porphyrin. While the ruthenium-based complex, ([Ru(CO)3Cl2]2), depended on the presence of Fe(II) species to release CO, it was found that the chromium-based complex released spontaneously CO. This was facilitated by illuminating and/or simple stirring of the solution containing the complex.
- Full Text:
- Date Issued: 2006
‘Exploring the practical adequacy of the human rights, social justice, inclusivity and healthy environment policy discourse in South Africa’s National Curriculum Statement’
- Schudel, Ingrid J, Lotz-Sisitka, Heila
- Authors: Schudel, Ingrid J , Lotz-Sisitka, Heila
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/391180 , vital:68629 , xlink:href="https://www.tandfonline.com/doi/full/10.1080/13504620701284860"
- Description: This article examines the practical adequacy of the recent defining of a normative framework for the South African National Curriculum Statement that focuses on the relationship between human rights, social justice and a healthy environment. This politically framed and socially critical normative framework has developed in response to socio-political and socio-ecological histories in postapartheid curriculum transformation processes. The article critically considers the process of working with a normative framework in the defining of environmental education teaching and learning interactions, and seeks not only to explore the policy discourse critically, but also to explore what it is about the world that makes it work in different ways. Drawing on Sayer’s perspectives on the possibilities of enabling ‘situated universalism’ as a form of normative theory, and case-based data from a teacher professional development programme in the Makana District (where the authors live and work), the article probes the relationship between the establishment of a ‘universalising’ normative framework to guide national curriculum, and situated engagements with this framework in/as democratic process. In this process it questions whether educators should adopt the ‘norms’ as presented by society and simply universalize and implement them as prescribed by curriculum statements, or whether educators should adopt the strategies of postmodernists and reduce normative frameworks to relations of power situated in particular contexts.
- Full Text:
- Date Issued: 2006
- Authors: Schudel, Ingrid J , Lotz-Sisitka, Heila
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/391180 , vital:68629 , xlink:href="https://www.tandfonline.com/doi/full/10.1080/13504620701284860"
- Description: This article examines the practical adequacy of the recent defining of a normative framework for the South African National Curriculum Statement that focuses on the relationship between human rights, social justice and a healthy environment. This politically framed and socially critical normative framework has developed in response to socio-political and socio-ecological histories in postapartheid curriculum transformation processes. The article critically considers the process of working with a normative framework in the defining of environmental education teaching and learning interactions, and seeks not only to explore the policy discourse critically, but also to explore what it is about the world that makes it work in different ways. Drawing on Sayer’s perspectives on the possibilities of enabling ‘situated universalism’ as a form of normative theory, and case-based data from a teacher professional development programme in the Makana District (where the authors live and work), the article probes the relationship between the establishment of a ‘universalising’ normative framework to guide national curriculum, and situated engagements with this framework in/as democratic process. In this process it questions whether educators should adopt the ‘norms’ as presented by society and simply universalize and implement them as prescribed by curriculum statements, or whether educators should adopt the strategies of postmodernists and reduce normative frameworks to relations of power situated in particular contexts.
- Full Text:
- Date Issued: 2006
Agroforestry tree products (AFTPs): Targeting poverty reduction and enhanced livelihoods
- Leakey, Roger R, Tchoundjeu, Zac, Schreckenberg, Kate, Shackleton, Sheona E, Shackleton, Charlie M
- Authors: Leakey, Roger R , Tchoundjeu, Zac , Schreckenberg, Kate , Shackleton, Sheona E , Shackleton, Charlie M
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182136 , vital:43803 , xlink:href="https://doi.org/10.1080/14735903.2005.9684741"
- Description: Agroforestry tree domestication emerged as a farmer-driven, market-led process in the early 1990s and became an international initiative. A participatory approach now supplements the more traditional aspects of tree improvement, and is seen as an important strategy towards the Millennium Development Goals of eradicating poverty and hunger, promoting social equity and environmental sustainability. Considerable progress has been made towards the domestication of indigenous fruits and nuts in many villages in Cameroon and Nigeria. Vegetatively-propagated cultivars based on a sound knowledge of ‘ideotypes’ derived from an understanding of the tree-to-tree variation in many commercially important traits are being developed by farmers. These are being integrated into polycultural farming systems, especially the cocoa agroforests. Markets for Agroforestry Tree Products (AFTPs) are crucial for the adoption of agroforestry on a scale to have meaningful economic, social and environmental impacts. Important lessons have been learned in southern Africa from detailed studies of the commercialization of AFTPs. These provide support for the wider acceptance of the role of domesticating indigenous trees in the promotion of enhanced livelihoods for poor farmers in the tropics. Policy guidelines have been developed in support of this sustainable rural development as an alternative strategy to those proposed in many other major development and conservation fora.
- Full Text:
- Date Issued: 2005
- Authors: Leakey, Roger R , Tchoundjeu, Zac , Schreckenberg, Kate , Shackleton, Sheona E , Shackleton, Charlie M
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182136 , vital:43803 , xlink:href="https://doi.org/10.1080/14735903.2005.9684741"
- Description: Agroforestry tree domestication emerged as a farmer-driven, market-led process in the early 1990s and became an international initiative. A participatory approach now supplements the more traditional aspects of tree improvement, and is seen as an important strategy towards the Millennium Development Goals of eradicating poverty and hunger, promoting social equity and environmental sustainability. Considerable progress has been made towards the domestication of indigenous fruits and nuts in many villages in Cameroon and Nigeria. Vegetatively-propagated cultivars based on a sound knowledge of ‘ideotypes’ derived from an understanding of the tree-to-tree variation in many commercially important traits are being developed by farmers. These are being integrated into polycultural farming systems, especially the cocoa agroforests. Markets for Agroforestry Tree Products (AFTPs) are crucial for the adoption of agroforestry on a scale to have meaningful economic, social and environmental impacts. Important lessons have been learned in southern Africa from detailed studies of the commercialization of AFTPs. These provide support for the wider acceptance of the role of domesticating indigenous trees in the promotion of enhanced livelihoods for poor farmers in the tropics. Policy guidelines have been developed in support of this sustainable rural development as an alternative strategy to those proposed in many other major development and conservation fora.
- Full Text:
- Date Issued: 2005
Cholera in KwaZulu-Natal: Probing institutional governmentality and indigenous hand-washing practices
- Authors: O'Donoghue, Rob B
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/373574 , vital:66704 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122699"
- Description: The paper reviews education activities in a successful anti-cholera campaign amongst rural communities in eastern southern Africa. It is centred on probing how a modern institutional governmentality was relatively blind to an historical legacy of Nguni hand-washing practices and came to exclude use of simple tests for coliform contamination in rural health education activities. The study examines institutional processes, probing discontinuities between the health education message and the complex social ecology of cholera. In so doing, it uncovers how a post-apartheid institutional rhetoric of participation, empowerment and social transformation is playing out in communicative interventions to instil healthier practices amongst the rural poor. Institutional perspectives such as this are rooted in an institutional legacy of appropriation and control. Despite the current rhetoric of participation, instrumental orientations are being sustained as the radical critique of struggle for freedom and change gives way, through comfortable submission and intellectual conformity, to an instrumental conservatism in many post-apartheid institutional settings today. The study notes and probes a surprising resonance between the ecology of the disease and an intergenerational social capital of indigenous hand-washing practices. The evidence suggests that these patterns of hand-washing practice would have served to contain the disease in earlier times and points to this social capital as a focus for co-engaged action on environment and health concerns. The findings suggest that an opposing of institutional and indigenous knowledge is not a simple matter and that moving beyond a legacy of cultural exclusion and marginalisation remains a challenge as the first decade of post-apartheid democratic governance comes to a close.
- Full Text:
- Date Issued: 2005
- Authors: O'Donoghue, Rob B
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/373574 , vital:66704 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122699"
- Description: The paper reviews education activities in a successful anti-cholera campaign amongst rural communities in eastern southern Africa. It is centred on probing how a modern institutional governmentality was relatively blind to an historical legacy of Nguni hand-washing practices and came to exclude use of simple tests for coliform contamination in rural health education activities. The study examines institutional processes, probing discontinuities between the health education message and the complex social ecology of cholera. In so doing, it uncovers how a post-apartheid institutional rhetoric of participation, empowerment and social transformation is playing out in communicative interventions to instil healthier practices amongst the rural poor. Institutional perspectives such as this are rooted in an institutional legacy of appropriation and control. Despite the current rhetoric of participation, instrumental orientations are being sustained as the radical critique of struggle for freedom and change gives way, through comfortable submission and intellectual conformity, to an instrumental conservatism in many post-apartheid institutional settings today. The study notes and probes a surprising resonance between the ecology of the disease and an intergenerational social capital of indigenous hand-washing practices. The evidence suggests that these patterns of hand-washing practice would have served to contain the disease in earlier times and points to this social capital as a focus for co-engaged action on environment and health concerns. The findings suggest that an opposing of institutional and indigenous knowledge is not a simple matter and that moving beyond a legacy of cultural exclusion and marginalisation remains a challenge as the first decade of post-apartheid democratic governance comes to a close.
- Full Text:
- Date Issued: 2005
Customary Sea Tenure in Oceania as a Case of Rights-based Fishery Management: Does it Work?
- Authors: Shankar, Aswani
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/439071 , vital:73542 , xlink:href="https://doi.org/10.1007/s11160-005-4868-x"
- Description: This paper outlines the general characteristics of customary sea tenure (CST) in Oceania and identifies areas in which these characteristics overlap with modern rights-based fisheries management systems such as ITQs and CDQs. It also examines the effectiveness of CST regimes at regulating marine resource use and access by focusing on a particular case from the Solomon Islands. The institutional robustness or vulnerability of CST is assessed by examining various performance criteria for two communities in the Roviana Lagoon, Western Solomons. These criteria include people’s (1) settlement patterns in relation to their property, (2) cultural consensus, (3) cultural attitudes with regard to governance and management, and (4) fishing efforts and yields. The results show that a number of historical processes have shaped CST systems into heterogeneous and dynamic institutions, and that CST regimes can vary even on small geographical scales. Understanding the circumstances in which CST regimes are more likely to be successful has facilitated the design and implementation of co-management fishery prescriptions (MPAs) for protecting particular species and habitats in the region. More generally, the paper proposes that by discerning the effectiveness of local governance institutions at regulating resource use and access – taking into consideration that these are embedded in particular historical and political contexts – we can better predict whether or not an introduced fishery management system will work. This knowledge can also assist in designing hybrid management schemes that cross-fertilize community-based management, modern rights-based fishery management (e.g., ITQs and CDQs), and other government regulations. This integration is particularly relevant when these policies are to be implemented in coastal communities that have or have had traditional rights-based fishery management systems of their own and/or are more socio-culturally homogeneous. Given the long history of failed fishery management, it is now of vital importance to design innovative fishery management prescriptions that integrate natural and social science research more comprehensively.
- Full Text:
- Date Issued: 2005
- Authors: Shankar, Aswani
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/439071 , vital:73542 , xlink:href="https://doi.org/10.1007/s11160-005-4868-x"
- Description: This paper outlines the general characteristics of customary sea tenure (CST) in Oceania and identifies areas in which these characteristics overlap with modern rights-based fisheries management systems such as ITQs and CDQs. It also examines the effectiveness of CST regimes at regulating marine resource use and access by focusing on a particular case from the Solomon Islands. The institutional robustness or vulnerability of CST is assessed by examining various performance criteria for two communities in the Roviana Lagoon, Western Solomons. These criteria include people’s (1) settlement patterns in relation to their property, (2) cultural consensus, (3) cultural attitudes with regard to governance and management, and (4) fishing efforts and yields. The results show that a number of historical processes have shaped CST systems into heterogeneous and dynamic institutions, and that CST regimes can vary even on small geographical scales. Understanding the circumstances in which CST regimes are more likely to be successful has facilitated the design and implementation of co-management fishery prescriptions (MPAs) for protecting particular species and habitats in the region. More generally, the paper proposes that by discerning the effectiveness of local governance institutions at regulating resource use and access – taking into consideration that these are embedded in particular historical and political contexts – we can better predict whether or not an introduced fishery management system will work. This knowledge can also assist in designing hybrid management schemes that cross-fertilize community-based management, modern rights-based fishery management (e.g., ITQs and CDQs), and other government regulations. This integration is particularly relevant when these policies are to be implemented in coastal communities that have or have had traditional rights-based fishery management systems of their own and/or are more socio-culturally homogeneous. Given the long history of failed fishery management, it is now of vital importance to design innovative fishery management prescriptions that integrate natural and social science research more comprehensively.
- Full Text:
- Date Issued: 2005
Effects of central metal on the photophysical and photochemical properties of non-transition metal sulfophthalocyanine
- Ogunsipe, Abimbola, Nyokong, Tebello
- Authors: Ogunsipe, Abimbola , Nyokong, Tebello
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/289337 , vital:56623 , xlink:href="https://doi.org/10.1142/S1088424605000186"
- Description: The photophysical and photochemical properties and quenching (by 1,4-benzoquinone) of metallophthalocyanine sulfonates of aluminium (AlPcSmix), zinc (ZnPcSmix), silicon (SiPcSmix), germanium (GePcSmix) and tin (SnPcSmix) are presented. The quantum yield values of fluorescence (ΦF), triplet state (ΦT), singlet oxygen (ΦΔ) and photodegradation (Φd) were determined and the observed trends in their variation among the complexes discussed in terms of aggregation and the heavy atom effect. 1,4-benzoquinone effectively quenched the fluorescence of the complexes. Quenching analyses gave positive deviations from Stern-Volmer behavior, suggesting the existence of static quenching in addition to dynamic quenching. The static and dynamic components of the quenching were separated using a modified Stern-Volmer equation and the “sphere of action quenching model”. The quenching constant was found to be a function of the radius of the central metal ion.
- Full Text:
- Date Issued: 2005
- Authors: Ogunsipe, Abimbola , Nyokong, Tebello
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/289337 , vital:56623 , xlink:href="https://doi.org/10.1142/S1088424605000186"
- Description: The photophysical and photochemical properties and quenching (by 1,4-benzoquinone) of metallophthalocyanine sulfonates of aluminium (AlPcSmix), zinc (ZnPcSmix), silicon (SiPcSmix), germanium (GePcSmix) and tin (SnPcSmix) are presented. The quantum yield values of fluorescence (ΦF), triplet state (ΦT), singlet oxygen (ΦΔ) and photodegradation (Φd) were determined and the observed trends in their variation among the complexes discussed in terms of aggregation and the heavy atom effect. 1,4-benzoquinone effectively quenched the fluorescence of the complexes. Quenching analyses gave positive deviations from Stern-Volmer behavior, suggesting the existence of static quenching in addition to dynamic quenching. The static and dynamic components of the quenching were separated using a modified Stern-Volmer equation and the “sphere of action quenching model”. The quenching constant was found to be a function of the radius of the central metal ion.
- Full Text:
- Date Issued: 2005
Electro-oxidation of phenol and its derivatives on poly-Ni (OH) TPhPyPc modified vitreous carbon electrodes
- Obirai, Joseph, Bedioui, Fethi, Nyokong, Tebello
- Authors: Obirai, Joseph , Bedioui, Fethi , Nyokong, Tebello
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/289353 , vital:56625 , xlink:href="https://doi.org/10.1016/j.jelechem.2004.11.006"
- Description: The electrochemical oxidation of phenol and its derivatives using poly-nickel hydroxy tetraphenoxypyrrolephthalocyanine (poly-Ni(OH)TPhPyPc) modified vitreous carbon electrodes are described. The films were formed by the electro-transformation of the electropolymerized pyrrole-substituted phenoxyphthalocyanine poly-NiTPhPyPc modified electrode in aqueous 0.1 M NaOH solution. The poly-Ni(OH)TPhPyPc films showed better stability and resistance to electrode fouling compared to poly-NiTPhPyPc and unmodified electrodes. The resistance to surface fouling and stability can be attributed to the structure of the ring substituent on the phthalocyanine macrocycle and to the particular O–Ni–O bridged architecture of the nickel phthalocyanine film.
- Full Text:
- Date Issued: 2005
- Authors: Obirai, Joseph , Bedioui, Fethi , Nyokong, Tebello
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/289353 , vital:56625 , xlink:href="https://doi.org/10.1016/j.jelechem.2004.11.006"
- Description: The electrochemical oxidation of phenol and its derivatives using poly-nickel hydroxy tetraphenoxypyrrolephthalocyanine (poly-Ni(OH)TPhPyPc) modified vitreous carbon electrodes are described. The films were formed by the electro-transformation of the electropolymerized pyrrole-substituted phenoxyphthalocyanine poly-NiTPhPyPc modified electrode in aqueous 0.1 M NaOH solution. The poly-Ni(OH)TPhPyPc films showed better stability and resistance to electrode fouling compared to poly-NiTPhPyPc and unmodified electrodes. The resistance to surface fouling and stability can be attributed to the structure of the ring substituent on the phthalocyanine macrocycle and to the particular O–Ni–O bridged architecture of the nickel phthalocyanine film.
- Full Text:
- Date Issued: 2005
Electrocatalytic oxidation and detection of hydrazine at gold electrode modified with iron phthalocyanine complex linked to mercaptopyridine self-assembled monolayer
- Ozoemena, Kenneth I, Nyokong, Tebello
- Authors: Ozoemena, Kenneth I , Nyokong, Tebello
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/286065 , vital:56235 , xlink:href="https://doi.org/10.1016/j.talanta.2005.02.030"
- Description: Electrocatalytic oxidation and detection of hydrazine in pH 7.0 conditions were studied by using gold electrode modified with self-assembled monolayer (SAM) films of iron phthalocyanine (FePc) complex axially ligated to a preformed 4-mercaptopyridine SAMs. The anodic oxidation of hydrazine in neutral pH conditions with FePc-linked-mercaptopyridine-SAM-modified gold electrode occurred at low overpotential (0.35 V versus Ag|AgCl) and the treatment of the voltammetric data showed that it was a pure diffusion-controlled reaction with the involvement of one electron in the rate-determining step. The mechanism for the interaction of hydrazine with the FePc-SAM is proposed to involve the Fe(III)Pc/Fe(II)Pc redox process. Using cyclic voltammetry (CV) and Osteryoung square wave voltammetry (OSWV), hydrazine was detected over a linear concentration range of 1.3 × 10−5 to 9.2 × 10−5 mol/L with low limits of detection (ca. 5 and 11 μM for OSWV and CV, respectively). At concentrations higher than 1.2 × 10−4 mol/L the anodic peak potential shifted to 0.40 V (versus Ag|AgCl), and this was interpreted to be due to kinetic limitations resulting from the saturation of hydrazine and its oxidation products onto the redox-active monolayer film. This type of metallophthalocyanine-SAM-based electrode is a highly promising electrochemical sensor given its ease of fabrication, good catalytic activity, stability, sensitivity and simplicity.
- Full Text:
- Date Issued: 2005
- Authors: Ozoemena, Kenneth I , Nyokong, Tebello
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/286065 , vital:56235 , xlink:href="https://doi.org/10.1016/j.talanta.2005.02.030"
- Description: Electrocatalytic oxidation and detection of hydrazine in pH 7.0 conditions were studied by using gold electrode modified with self-assembled monolayer (SAM) films of iron phthalocyanine (FePc) complex axially ligated to a preformed 4-mercaptopyridine SAMs. The anodic oxidation of hydrazine in neutral pH conditions with FePc-linked-mercaptopyridine-SAM-modified gold electrode occurred at low overpotential (0.35 V versus Ag|AgCl) and the treatment of the voltammetric data showed that it was a pure diffusion-controlled reaction with the involvement of one electron in the rate-determining step. The mechanism for the interaction of hydrazine with the FePc-SAM is proposed to involve the Fe(III)Pc/Fe(II)Pc redox process. Using cyclic voltammetry (CV) and Osteryoung square wave voltammetry (OSWV), hydrazine was detected over a linear concentration range of 1.3 × 10−5 to 9.2 × 10−5 mol/L with low limits of detection (ca. 5 and 11 μM for OSWV and CV, respectively). At concentrations higher than 1.2 × 10−4 mol/L the anodic peak potential shifted to 0.40 V (versus Ag|AgCl), and this was interpreted to be due to kinetic limitations resulting from the saturation of hydrazine and its oxidation products onto the redox-active monolayer film. This type of metallophthalocyanine-SAM-based electrode is a highly promising electrochemical sensor given its ease of fabrication, good catalytic activity, stability, sensitivity and simplicity.
- Full Text:
- Date Issued: 2005