A review of the biocontrol programmes against aquatic weeds in South Africa
- Coetzee, Julie A, Bownes, Angela, Martin, Grant D, Miller, Benjamin E, Smith, Rosalie, Weyl, Philip S R, Hill, Martin P
- Authors: Coetzee, Julie A , Bownes, Angela , Martin, Grant D , Miller, Benjamin E , Smith, Rosalie , Weyl, Philip S R , Hill, Martin P
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/406965 , vital:70326 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v29_n3_a18"
- Description: Biological control (biocontrol) against invasive macrophytes is one of the longest standing programmes in South Africa, initiated in the 1970s against water hyacinth, Pontederia crassipes Mart. (Pontederiaceae). Since then, 15 agent species (13 insects, one mite and one pathogen) have been released against six weeds, most of which are floating macrophytes, with excellent levels of success. The release of the water hyacinth planthopper Megamelus scutellaris Berg (Hemiptera: Delphacidae) in particular, has improved biocontrol prospects for water hyacinth since 2018. In the last decade, however, a new suite of submerged and rooted emergent invasive macrophytes has been targeted. The first release against a submerged macrophyte in South Africa, and the first release against Brazilian waterweed, Egeria densa Planch. (Hydrocharitaceae), anywhere in the world, was achieved with the release of a leafmining fly, Hydrellia egeriae Rodrigues-Júnior, Mathis and Hauser (Diptera: Ephydridae). Yellow flag, Iris pseudacorus L. (Iridaceae) and Mexican waterlily, Nymphaea mexicana Zucc. (Nymphaeaceae), have also been targeted for biocontrol for the first time worldwide, and are in the early stages of agent development. Post-release evaluations, long term monitoring and controlled experiments have highlighted the need for a more holistic approach to managing aquatic invasive plants in South Africa, whose presence is largely driven by eutrophication, resulting in regime shifts between floating and submerged invaded states.
- Full Text:
- Date Issued: 2021
- Authors: Coetzee, Julie A , Bownes, Angela , Martin, Grant D , Miller, Benjamin E , Smith, Rosalie , Weyl, Philip S R , Hill, Martin P
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/406965 , vital:70326 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v29_n3_a18"
- Description: Biological control (biocontrol) against invasive macrophytes is one of the longest standing programmes in South Africa, initiated in the 1970s against water hyacinth, Pontederia crassipes Mart. (Pontederiaceae). Since then, 15 agent species (13 insects, one mite and one pathogen) have been released against six weeds, most of which are floating macrophytes, with excellent levels of success. The release of the water hyacinth planthopper Megamelus scutellaris Berg (Hemiptera: Delphacidae) in particular, has improved biocontrol prospects for water hyacinth since 2018. In the last decade, however, a new suite of submerged and rooted emergent invasive macrophytes has been targeted. The first release against a submerged macrophyte in South Africa, and the first release against Brazilian waterweed, Egeria densa Planch. (Hydrocharitaceae), anywhere in the world, was achieved with the release of a leafmining fly, Hydrellia egeriae Rodrigues-Júnior, Mathis and Hauser (Diptera: Ephydridae). Yellow flag, Iris pseudacorus L. (Iridaceae) and Mexican waterlily, Nymphaea mexicana Zucc. (Nymphaeaceae), have also been targeted for biocontrol for the first time worldwide, and are in the early stages of agent development. Post-release evaluations, long term monitoring and controlled experiments have highlighted the need for a more holistic approach to managing aquatic invasive plants in South Africa, whose presence is largely driven by eutrophication, resulting in regime shifts between floating and submerged invaded states.
- Full Text:
- Date Issued: 2021
A Search for Conjunctions at a Time of Direction-setting Review and Synthesis
- Authors: O'Donoghue, Rob
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/387134 , vital:68209 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122240"
- Description: This journal reflects a diversity of environment and sustainability education research and viewpoints alongside two synthesis papers. Read as a whole and within a widely held ideal that diversity reflects resilience, the environment and education for sustainable development landscape in Africa might be said to be healthy and proliferating. But read against the pressure to produce tangible evidence of change on an African landscape of persistent climate variation and poverty, along with a widening gap between rich and poor, the picture remains challenging. These contrasting readings are notable at a time when we are looking towards the Association for the Development of Education in Africa (ADEA) Triennial in February, 2012, the Rio+20 Earth Summit in June 2012 and our own EEASA +30 conference in September 2012. The UN Decade of Education for Sustainable Development is characterised by a proliferation of education imperatives. These emerged as modern education in response to the issues of the day and now a modernity in deepening crisis.
- Full Text:
- Date Issued: 2011
- Authors: O'Donoghue, Rob
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/387134 , vital:68209 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122240"
- Description: This journal reflects a diversity of environment and sustainability education research and viewpoints alongside two synthesis papers. Read as a whole and within a widely held ideal that diversity reflects resilience, the environment and education for sustainable development landscape in Africa might be said to be healthy and proliferating. But read against the pressure to produce tangible evidence of change on an African landscape of persistent climate variation and poverty, along with a widening gap between rich and poor, the picture remains challenging. These contrasting readings are notable at a time when we are looking towards the Association for the Development of Education in Africa (ADEA) Triennial in February, 2012, the Rio+20 Earth Summit in June 2012 and our own EEASA +30 conference in September 2012. The UN Decade of Education for Sustainable Development is characterised by a proliferation of education imperatives. These emerged as modern education in response to the issues of the day and now a modernity in deepening crisis.
- Full Text:
- Date Issued: 2011
A sensitive and reliable method for the detection of lipid peroxidation in biological tissues
- Anoopkumar-Dukie, Shailendra, Walker, Roderick B, Daya, Santylal
- Authors: Anoopkumar-Dukie, Shailendra , Walker, Roderick B , Daya, Santylal
- Date: 2001
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184325 , vital:44208 , xlink:href="https://doi.org/10.1211/0022357011775299"
- Description: A simple, accurate and cost effective method has been designed for the determination of lipid peroxidation in biological tissue samples. The method was a modification and improvement on existing methods available for lipid peroxidation determination. Solid-phase extraction was used to separate the thiobarbituric acid–malondialdehyde complex from thiobarbituric acidreactive substances and HPLC was performed using a C18 (Waters Spherisorb, 5 µm, 250¬4.6 mm i.d.) column to achieve isolation of the complex. The procedure was validated with respect to linearity of calibration (0.998), precision, sensitivity and limits of quantitation (1 nmol mL−1) and detection (0.5 nmol mL−1). Resorcinol was used as an external standard. The method was tested by inducing free radical generation with a known free radical generator, quinolinic acid, in rat brain homogenate. The results showed that the method presented allowed detection of lipid peroxidation products at concentrations in the nanomolar (nM) range compared with the micromolar (µM) range detected by other methods, thus rendering it suitable for use with biological samples. In addition, the modified method allowed for detection of the purified lipid peroxidation products, thus eliminating the possibility of simultaneous detection of impurities that absorb at the same wavelength.
- Full Text:
- Date Issued: 2001
- Authors: Anoopkumar-Dukie, Shailendra , Walker, Roderick B , Daya, Santylal
- Date: 2001
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184325 , vital:44208 , xlink:href="https://doi.org/10.1211/0022357011775299"
- Description: A simple, accurate and cost effective method has been designed for the determination of lipid peroxidation in biological tissue samples. The method was a modification and improvement on existing methods available for lipid peroxidation determination. Solid-phase extraction was used to separate the thiobarbituric acid–malondialdehyde complex from thiobarbituric acidreactive substances and HPLC was performed using a C18 (Waters Spherisorb, 5 µm, 250¬4.6 mm i.d.) column to achieve isolation of the complex. The procedure was validated with respect to linearity of calibration (0.998), precision, sensitivity and limits of quantitation (1 nmol mL−1) and detection (0.5 nmol mL−1). Resorcinol was used as an external standard. The method was tested by inducing free radical generation with a known free radical generator, quinolinic acid, in rat brain homogenate. The results showed that the method presented allowed detection of lipid peroxidation products at concentrations in the nanomolar (nM) range compared with the micromolar (µM) range detected by other methods, thus rendering it suitable for use with biological samples. In addition, the modified method allowed for detection of the purified lipid peroxidation products, thus eliminating the possibility of simultaneous detection of impurities that absorb at the same wavelength.
- Full Text:
- Date Issued: 2001
A simple quinoline-thiophene Schiff base turn-off chemosensor for Hg2+ detection
- Musikavanhu, Brian, Muthusamy, Selvaraj, Zhu, Dongwei, Xue, Zhaoli, Yu, Qian, Chivumba, Choonzo N, Mack, John, Nyokong, Tebello, Wang, Shengjun, Zhao, Long
- Authors: Musikavanhu, Brian , Muthusamy, Selvaraj , Zhu, Dongwei , Xue, Zhaoli , Yu, Qian , Chivumba, Choonzo N , Mack, John , Nyokong, Tebello , Wang, Shengjun , Zhao, Long
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/230362 , vital:49771 , xlink:href="https://doi.org/10.1016/j.saa.2021.120338"
- Description: A new Schiff base probe (QT) consisting of 8-aminoquinoline (Q) and thiophene-2-carboxaldehyde (T) moieties has been synthesized. QT undergoes chelation-enhanced fluorescence quenching when exposed to Hg2+ due to coordination by the sulfur and nitrogen atoms of QT thus forming a facile “turn-off” sensor. The formation of the chelation complex was confirmed by UV–visible absorption and emission spectral measurements, 1H NMR titration and density functional theory calculations. These studies revealed that the probe exhibits high selectivity and sensitivity towards Hg2+ in the presence of other common metal ions. A low detection limit of 23.4 nM was determined and a Job plot confirmed a 2:1 stoichiometry between QT and Hg2+. The potential utility of QT as a sensor for Hg2+ ions in human HeLa cells was determined by confocal fluorescence microscopy, and its suitability for use in the field with environmental samples was tested with Whatman filter paper strips.
- Full Text:
- Date Issued: 2022
- Authors: Musikavanhu, Brian , Muthusamy, Selvaraj , Zhu, Dongwei , Xue, Zhaoli , Yu, Qian , Chivumba, Choonzo N , Mack, John , Nyokong, Tebello , Wang, Shengjun , Zhao, Long
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/230362 , vital:49771 , xlink:href="https://doi.org/10.1016/j.saa.2021.120338"
- Description: A new Schiff base probe (QT) consisting of 8-aminoquinoline (Q) and thiophene-2-carboxaldehyde (T) moieties has been synthesized. QT undergoes chelation-enhanced fluorescence quenching when exposed to Hg2+ due to coordination by the sulfur and nitrogen atoms of QT thus forming a facile “turn-off” sensor. The formation of the chelation complex was confirmed by UV–visible absorption and emission spectral measurements, 1H NMR titration and density functional theory calculations. These studies revealed that the probe exhibits high selectivity and sensitivity towards Hg2+ in the presence of other common metal ions. A low detection limit of 23.4 nM was determined and a Job plot confirmed a 2:1 stoichiometry between QT and Hg2+. The potential utility of QT as a sensor for Hg2+ ions in human HeLa cells was determined by confocal fluorescence microscopy, and its suitability for use in the field with environmental samples was tested with Whatman filter paper strips.
- Full Text:
- Date Issued: 2022
A Sn (iv) porphyrin with mitochondria targeting properties for enhanced photodynamic activity against MCF-7 cells
- Babu, Balaji, Mack, John, Nyokong, Tebello
- Authors: Babu, Balaji , Mack, John , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/230897 , vital:49829 , xlink:href="https://doi.org/10.1039/D2NJ00350C"
- Description: Two readily synthesized Sn(IV) porphyrins (SnP, SnPH) have been prepared with and without the cationic triphenylphosphonium moiety (TPP+), which have high singlet oxygen quantum yields (ca. 0.72) and long triplet state lifetimes. The Sn(IV) porphyrin with a TPP+ moiety (SnPH) exhibits favorable photodynamic activity against MCF-7 cells with IC50 values of 2.9 μM. SnPH exhibits higher cellular uptake than SnP in MCF-7 cells. A Rhodamine 123 (Rh123) assay showed that SnPH targets mitochondria and induces apoptosis by generating reactive oxygen species. The results demonstrate that this structural modification strategy merits further in-depth study.
- Full Text:
- Date Issued: 2022
- Authors: Babu, Balaji , Mack, John , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/230897 , vital:49829 , xlink:href="https://doi.org/10.1039/D2NJ00350C"
- Description: Two readily synthesized Sn(IV) porphyrins (SnP, SnPH) have been prepared with and without the cationic triphenylphosphonium moiety (TPP+), which have high singlet oxygen quantum yields (ca. 0.72) and long triplet state lifetimes. The Sn(IV) porphyrin with a TPP+ moiety (SnPH) exhibits favorable photodynamic activity against MCF-7 cells with IC50 values of 2.9 μM. SnPH exhibits higher cellular uptake than SnP in MCF-7 cells. A Rhodamine 123 (Rh123) assay showed that SnPH targets mitochondria and induces apoptosis by generating reactive oxygen species. The results demonstrate that this structural modification strategy merits further in-depth study.
- Full Text:
- Date Issued: 2022
A spatio-temporal, landscape perspective on Acacia dealbata invasions and broader land use and cover changes in the northern Eastern Cape, South Africa
- Gouws, Aidan J, Prof.Shackleton, Charlie M
- Authors: Gouws, Aidan J , Prof.Shackleton, Charlie M
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/179670 , vital:43156 , xlink:href="https://doi.org/10.1007/s10661-019-7204-y"
- Description: Biological invasions and human land use both have the potential to drastically alter the patterns and processes of landscapes, driving habitat fragmentation and altering natural disturbance regimes. The proliferation of an invasive species depends on composition and configuration of the landscape, as well as the invasiveness of the species. To effectively manage a highly invasive species, such as Acacia dealbata, it is crucial to understand the historical progression of the invasion within the landscape. This study sought to examine the landscape dynamics of biological invasions by tracking the historical spread of A. dealbata and broader land use/land cover (LULC) changes at different spatiotemporal scales in the northern Eastern Cape. A timeseries of aerial photographs were systematically classified according to designated A. dealbata and LULC categories in ArcGIS to track the changes in the extent and rate of spread of A. dealbata. Markedly dynamic, multi-directional, and spatio-temporally variable LULC transitions were observed across the northern Eastern Cape over the last six decades. A. dealbata frequently retained a high proportion of cover over time, and despite the loss of cover to other LULC classes, a net increase in A. dealbata cover occurred as it spread at an overall annual rate of 0.11–0.21%, occupying approximately 8–18% of land cover across all sampled sites by 2013.
- Full Text:
- Date Issued: 2019
- Authors: Gouws, Aidan J , Prof.Shackleton, Charlie M
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/179670 , vital:43156 , xlink:href="https://doi.org/10.1007/s10661-019-7204-y"
- Description: Biological invasions and human land use both have the potential to drastically alter the patterns and processes of landscapes, driving habitat fragmentation and altering natural disturbance regimes. The proliferation of an invasive species depends on composition and configuration of the landscape, as well as the invasiveness of the species. To effectively manage a highly invasive species, such as Acacia dealbata, it is crucial to understand the historical progression of the invasion within the landscape. This study sought to examine the landscape dynamics of biological invasions by tracking the historical spread of A. dealbata and broader land use/land cover (LULC) changes at different spatiotemporal scales in the northern Eastern Cape. A timeseries of aerial photographs were systematically classified according to designated A. dealbata and LULC categories in ArcGIS to track the changes in the extent and rate of spread of A. dealbata. Markedly dynamic, multi-directional, and spatio-temporally variable LULC transitions were observed across the northern Eastern Cape over the last six decades. A. dealbata frequently retained a high proportion of cover over time, and despite the loss of cover to other LULC classes, a net increase in A. dealbata cover occurred as it spread at an overall annual rate of 0.11–0.21%, occupying approximately 8–18% of land cover across all sampled sites by 2013.
- Full Text:
- Date Issued: 2019
A stability-indicating high performance liquid chromatographic assay for the determination of orlistat in capsules
- Mohammadi, Ali, Haririan, I, Rezanour, Nasrin, Ghiasi, L, Walker, Roderick B
- Authors: Mohammadi, Ali , Haririan, I , Rezanour, Nasrin , Ghiasi, L , Walker, Roderick B
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184267 , vital:44195 , xlink:href="https://doi.org/10.1016/j.chroma.2006.03.038"
- Description: A stability-indicating HPLC method was developed and validated for the quantitative determination of orlistat in capsule dosage forms. An isocratic separation was achieved using a Perfectsil® target ODS-3, 250 mm × 4.6 mm i.d., 5 μm particle size column with a flow rate of 0.7 ml/min and using a UV detector to monitor the eluate at 210 nm. The mobile phase consisted of methanol:acetonitrile:trifluoroacetic acid (82.5:17.5:0.01, v/v/v). The drug was subjected oxidation, hydrolysis, photolysis and heat to apply stress conditions. Complete separation was achieved for the parent compound and all degradation products in an overall analytical run time of approximately 15 min with the parent compound orlistat eluting at approximately 9 min. The method was linear over the concentration range of 0.02–0.75 mg/ml (r = 0.9998) with a limit of detection and quantitation 0.006 and 0.02 mg/ml, respectively. The method has the requisite accuracy, selectivity, sensitivity and precision to assay orlistat in capsules. Degradation products resulting from the stress studies did not interfere with the detection of orlistat and the assay is thus stability-indicating.
- Full Text:
- Date Issued: 2006
- Authors: Mohammadi, Ali , Haririan, I , Rezanour, Nasrin , Ghiasi, L , Walker, Roderick B
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184267 , vital:44195 , xlink:href="https://doi.org/10.1016/j.chroma.2006.03.038"
- Description: A stability-indicating HPLC method was developed and validated for the quantitative determination of orlistat in capsule dosage forms. An isocratic separation was achieved using a Perfectsil® target ODS-3, 250 mm × 4.6 mm i.d., 5 μm particle size column with a flow rate of 0.7 ml/min and using a UV detector to monitor the eluate at 210 nm. The mobile phase consisted of methanol:acetonitrile:trifluoroacetic acid (82.5:17.5:0.01, v/v/v). The drug was subjected oxidation, hydrolysis, photolysis and heat to apply stress conditions. Complete separation was achieved for the parent compound and all degradation products in an overall analytical run time of approximately 15 min with the parent compound orlistat eluting at approximately 9 min. The method was linear over the concentration range of 0.02–0.75 mg/ml (r = 0.9998) with a limit of detection and quantitation 0.006 and 0.02 mg/ml, respectively. The method has the requisite accuracy, selectivity, sensitivity and precision to assay orlistat in capsules. Degradation products resulting from the stress studies did not interfere with the detection of orlistat and the assay is thus stability-indicating.
- Full Text:
- Date Issued: 2006
A study of the photophysicochemical and antimicrobial properties of two zinc phthalocyanine–silver nanoparticle conjugates
- Rapulenyane, Nomasonto, Antunes, Edith M, Nyokong, Tebello
- Authors: Rapulenyane, Nomasonto , Antunes, Edith M , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/232522 , vital:49999 , xlink:href="https://doi.org/10.1039/C3NJ41107A"
- Description: This work reports conjugation of two mono carboxy substituted zinc phthalocyanines with glutathione capped silver nanoparticles (GSH-AgNPs). The photophysicochemical behaviour of the novel phthalocyanines–silver nanoparticle conjugates was investigated together with simple mixtures of the silver nanoparticles with low symmetry phthalocyanines (i.e. with no direct chemical bond formation). It was observed that upon conjugation of the phthalocyanines to the silver nanoparticles, a blue shifting of the Q band was induced. The triplet lifetimes and quantum yields improved upon conjugation as compared to the phthalocyanines alone. Fluorescence lifetimes and quantum yields decreased for conjugates compared to the phthalocyanines alone due to quenching caused by the silver nanoparticles. The low symmetry phthalocyanines and their conjugates showed antimicrobial activity against Escherichia coli in the presence and absence of light.
- Full Text:
- Date Issued: 2013
- Authors: Rapulenyane, Nomasonto , Antunes, Edith M , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/232522 , vital:49999 , xlink:href="https://doi.org/10.1039/C3NJ41107A"
- Description: This work reports conjugation of two mono carboxy substituted zinc phthalocyanines with glutathione capped silver nanoparticles (GSH-AgNPs). The photophysicochemical behaviour of the novel phthalocyanines–silver nanoparticle conjugates was investigated together with simple mixtures of the silver nanoparticles with low symmetry phthalocyanines (i.e. with no direct chemical bond formation). It was observed that upon conjugation of the phthalocyanines to the silver nanoparticles, a blue shifting of the Q band was induced. The triplet lifetimes and quantum yields improved upon conjugation as compared to the phthalocyanines alone. Fluorescence lifetimes and quantum yields decreased for conjugates compared to the phthalocyanines alone due to quenching caused by the silver nanoparticles. The low symmetry phthalocyanines and their conjugates showed antimicrobial activity against Escherichia coli in the presence and absence of light.
- Full Text:
- Date Issued: 2013
A study on the morphology of thin copper films on para-aramid yarns and their influence on the yarn’s electro-conductive and mechanical properties
- Schwarz, Anne, Hakuzimana, Jean, Westbroek, Philippe, Mey, Gilbert De, Priniotakis, Georgios, Nyokong, Tebello, Langenhove, Lieva Van
- Authors: Schwarz, Anne , Hakuzimana, Jean , Westbroek, Philippe , Mey, Gilbert De , Priniotakis, Georgios , Nyokong, Tebello , Langenhove, Lieva Van
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/243487 , vital:51157 , xlink:href="https://doi.org/10.1177/0040517511431291"
- Description: The latest technological advances in new materials and devices enabled wearable systems to be created by utilizing textile solutions. These solutions require electro-conductive yarns as a basic component. Although the production of electroconductive yarn is widely reported, research is still necessary to characterize them to advance their electro-conductive and mechanical properties. Hence, we served this need and characterized copper-coated para-aramid yarns produced by an in-house developed electroless deposition method. In this paper we present our investigation on the yarn’s copper layer characteristics after deposition. Furthermore, we looked, in depth, at the yarn’s electro-conductive properties before and after washing as well as their mechanical properties before and after copper deposition. We found a dependency of the copper layer morphology on its deposition time. This is directly correlated to the resulting layer thickness and hence to the yarn’s electro-conductive properties, demonstrating the autocatalytic nature of the coating process. Above that, the electro-conductive properties of the coated yarn linearly decrease with washing cycles. Furthermore, the copper coating impairs the yarn’s mechanical properties decreasing its specific stress at break by 30%.
- Full Text:
- Date Issued: 2012
- Authors: Schwarz, Anne , Hakuzimana, Jean , Westbroek, Philippe , Mey, Gilbert De , Priniotakis, Georgios , Nyokong, Tebello , Langenhove, Lieva Van
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/243487 , vital:51157 , xlink:href="https://doi.org/10.1177/0040517511431291"
- Description: The latest technological advances in new materials and devices enabled wearable systems to be created by utilizing textile solutions. These solutions require electro-conductive yarns as a basic component. Although the production of electroconductive yarn is widely reported, research is still necessary to characterize them to advance their electro-conductive and mechanical properties. Hence, we served this need and characterized copper-coated para-aramid yarns produced by an in-house developed electroless deposition method. In this paper we present our investigation on the yarn’s copper layer characteristics after deposition. Furthermore, we looked, in depth, at the yarn’s electro-conductive properties before and after washing as well as their mechanical properties before and after copper deposition. We found a dependency of the copper layer morphology on its deposition time. This is directly correlated to the resulting layer thickness and hence to the yarn’s electro-conductive properties, demonstrating the autocatalytic nature of the coating process. Above that, the electro-conductive properties of the coated yarn linearly decrease with washing cycles. Furthermore, the copper coating impairs the yarn’s mechanical properties decreasing its specific stress at break by 30%.
- Full Text:
- Date Issued: 2012
A systematic analysis of doctoral publication trends in South Africa
- van Schalkwyk, Susan, Mouton, Johann, Redlinghuys, Herman, McKenna, Sioux
- Authors: van Schalkwyk, Susan , Mouton, Johann , Redlinghuys, Herman , McKenna, Sioux
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185826 , vital:44438 , xlink:href="http://dx.doi.org/10.17159/sajs.2020/7926"
- Description: It is incumbent upon doctoral students that their work makes a substantive contribution to the field within which it is conducted. Dissemination of this work beyond the dissertation, whether whilst studying or after graduation, is necessary to ensure that the contribution does not remain largely dormant. While dissemination can take many forms, peer-reviewed journal articles are the key medium by which knowledge is shared. We aimed to establish the proportion of doctoral theses that results in journal publications by linking South African doctoral thesis metadata to journal articles authored by doctoral candidates. To effect this matching, a customised data set was created that comprised two large databases: the South African Theses Database (SATD), which documented all doctoral degrees awarded in South Africa (2005-2014), and the South African Knowledgebase (SAK), which listed all publications submitted for subsidy to the South African Department of Higher Education and Training (2005-2017). The process followed several iterations of matching and verification, including manual inspection of the data, in order to isolate only those records for which the link was established beyond doubt. Over the period under review, 47.6% of graduates, representing 22 of the 26 higher education institutions, published at least one journal article. Results further indicate increasingly higher publication rates over time. To explore whether the journal article identified was a direct product of the study, a similarity index was developed. Over 75% of records demonstrated high similarity. While the trend towards increasing publications by graduates is promising, work in this area should be ongoing. In spite of increasing trends in publications by graduates, many are not disseminating their work, suggesting that significant bodies of research are potentially not being shared with the academic community and are therefore not contributing to the relevant discipline or field. •This study provides baseline data from which a number of further investigations can be launched, such as exploring the extent to which doctoral candidates who are also academics are publishing their work; the factors that enable or constrain publication; the other avenues of dissemination used; and whether publishing or not publishing can serve as a proxy for the quality of the doctoral work.
- Full Text:
- Date Issued: 2020
- Authors: van Schalkwyk, Susan , Mouton, Johann , Redlinghuys, Herman , McKenna, Sioux
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185826 , vital:44438 , xlink:href="http://dx.doi.org/10.17159/sajs.2020/7926"
- Description: It is incumbent upon doctoral students that their work makes a substantive contribution to the field within which it is conducted. Dissemination of this work beyond the dissertation, whether whilst studying or after graduation, is necessary to ensure that the contribution does not remain largely dormant. While dissemination can take many forms, peer-reviewed journal articles are the key medium by which knowledge is shared. We aimed to establish the proportion of doctoral theses that results in journal publications by linking South African doctoral thesis metadata to journal articles authored by doctoral candidates. To effect this matching, a customised data set was created that comprised two large databases: the South African Theses Database (SATD), which documented all doctoral degrees awarded in South Africa (2005-2014), and the South African Knowledgebase (SAK), which listed all publications submitted for subsidy to the South African Department of Higher Education and Training (2005-2017). The process followed several iterations of matching and verification, including manual inspection of the data, in order to isolate only those records for which the link was established beyond doubt. Over the period under review, 47.6% of graduates, representing 22 of the 26 higher education institutions, published at least one journal article. Results further indicate increasingly higher publication rates over time. To explore whether the journal article identified was a direct product of the study, a similarity index was developed. Over 75% of records demonstrated high similarity. While the trend towards increasing publications by graduates is promising, work in this area should be ongoing. In spite of increasing trends in publications by graduates, many are not disseminating their work, suggesting that significant bodies of research are potentially not being shared with the academic community and are therefore not contributing to the relevant discipline or field. •This study provides baseline data from which a number of further investigations can be launched, such as exploring the extent to which doctoral candidates who are also academics are publishing their work; the factors that enable or constrain publication; the other avenues of dissemination used; and whether publishing or not publishing can serve as a proxy for the quality of the doctoral work.
- Full Text:
- Date Issued: 2020
A white man in exile
- Authors: Krueger, Anton
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/229459 , vital:49677 , xlink:href="https://doi.org/10.1080/10137548.2011.636974"
- Description: This article explores intersections between understandings of masculinity and nationalism. Etymologically, ‘patriotism’ refers to a love for a fatherland and a patriarchal order; it includes notions of loyalty, honour and a range of qualities often associated with conceptions of masculinity. But if gender remains fixed to these normative constructions, what happens to one’s sense of masculine identity when the national state changes? My interest lies in exploring how white South African men have been repositioned in terms of a shift in their gendered identification, with a reflection on the possibly tragic consequences of maintaining an overly rigid gender role identification. As long as masculinity is embedded within nationalism, it will be caught up within a defensive reactive mode which can turn self-destructive. In order to explore these ideas the article employs as its central metaphor the character of Dawid Olivier, who is the protagonist of Athol Fugard’s Sorrows and Rejoicings (2002).
- Full Text:
- Date Issued: 2011
- Authors: Krueger, Anton
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/229459 , vital:49677 , xlink:href="https://doi.org/10.1080/10137548.2011.636974"
- Description: This article explores intersections between understandings of masculinity and nationalism. Etymologically, ‘patriotism’ refers to a love for a fatherland and a patriarchal order; it includes notions of loyalty, honour and a range of qualities often associated with conceptions of masculinity. But if gender remains fixed to these normative constructions, what happens to one’s sense of masculine identity when the national state changes? My interest lies in exploring how white South African men have been repositioned in terms of a shift in their gendered identification, with a reflection on the possibly tragic consequences of maintaining an overly rigid gender role identification. As long as masculinity is embedded within nationalism, it will be caught up within a defensive reactive mode which can turn self-destructive. In order to explore these ideas the article employs as its central metaphor the character of Dawid Olivier, who is the protagonist of Athol Fugard’s Sorrows and Rejoicings (2002).
- Full Text:
- Date Issued: 2011
A2B type copper (III) corroles containing zero-to-five fluorine atoms
- Li, Minzhi, Niu, Yingjie, Zhu, Weihua, Mack, John, Fomo, Gertrude, Nyokong, Tebello, Liang, Xu
- Authors: Li, Minzhi , Niu, Yingjie , Zhu, Weihua , Mack, John , Fomo, Gertrude , Nyokong, Tebello , Liang, Xu
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/238275 , vital:50604 , xlink:href="https://doi.org/10.1016/j.dyepig.2016.10.044"
- Description: Four low symmetric A2B meso-substituted Cu(III)corroles with electron withdrawing meso-aryl rings have been synthesized and characterized. A detailed analysis of the optical and redox properties has been carried out by comparing their optical spectroscopy, electrochemistry and spectroelectrochemistry to a series of DFT and TD-DFT calculations. A series of experiments demonstrate that these Cu(III)corroles can be used as highly effective catalysts for hydrogen evolution reactions (HERs). Moreover, when the number of fluorine atoms at B meso-position is increased, there is a marked enhancement in the catalytic ability of the corrole complexes, which demonstrates that modification to the structures of low symmetry corroles is a useful strategy for developing new HER catalysts.
- Full Text:
- Date Issued: 2017
- Authors: Li, Minzhi , Niu, Yingjie , Zhu, Weihua , Mack, John , Fomo, Gertrude , Nyokong, Tebello , Liang, Xu
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/238275 , vital:50604 , xlink:href="https://doi.org/10.1016/j.dyepig.2016.10.044"
- Description: Four low symmetric A2B meso-substituted Cu(III)corroles with electron withdrawing meso-aryl rings have been synthesized and characterized. A detailed analysis of the optical and redox properties has been carried out by comparing their optical spectroscopy, electrochemistry and spectroelectrochemistry to a series of DFT and TD-DFT calculations. A series of experiments demonstrate that these Cu(III)corroles can be used as highly effective catalysts for hydrogen evolution reactions (HERs). Moreover, when the number of fluorine atoms at B meso-position is increased, there is a marked enhancement in the catalytic ability of the corrole complexes, which demonstrates that modification to the structures of low symmetry corroles is a useful strategy for developing new HER catalysts.
- Full Text:
- Date Issued: 2017
Abundance and correlates of the Acacia dealbata invasion in the northern Eastern Cape, South Africa
- Gouws, Aidan J, Shackleton, Charlie M
- Authors: Gouws, Aidan J , Shackleton, Charlie M
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/179735 , vital:43165 , xlink:href="https://doi.org/10.1016/j.foreco.2018.09.048"
- Description: An increase in the density and biomass of woody invasive plants contributes to the intensification of ecological impacts and can often be met with dissatisfaction by local communities. Despite their reliance on Acacia dealbata as a source of livelihood, villagers in the northern Eastern Cape have expressed concerns about the high densities of the species. This study sought to quantify the current abundance and growth of A. dealbata in selected landscapes in the northern Eastern Cape, around nine villages in rural Matatiele, Mount Fletcher and Maclear. Standard vegetation survey techniques were adopted to quantify the density, biomass and growth rate of A. dealbata. Overall, the average density, biomass and productivity of A. dealbata were estimated at approximately 7000 stems ha−1, 12 Mg ha−1 and 4 Mg ha−1 year−1, respectively. However, the abundance and productivity of A. dealbata were spatially variable between study areas. Acacia dealbata stems experienced significant growth over the period of a single year, contributing to substantial biomass production at the landscape level, despite continued harvest. Furthermore, relatively few biophysical variables were significantly influential correlates with the abundance of A. dealbata. Indeed, the degree of biological invasion can be highly variable across the landscape, shaped by the interaction of local-scale biophysical conditions.
- Full Text:
- Date Issued: 2019
- Authors: Gouws, Aidan J , Shackleton, Charlie M
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/179735 , vital:43165 , xlink:href="https://doi.org/10.1016/j.foreco.2018.09.048"
- Description: An increase in the density and biomass of woody invasive plants contributes to the intensification of ecological impacts and can often be met with dissatisfaction by local communities. Despite their reliance on Acacia dealbata as a source of livelihood, villagers in the northern Eastern Cape have expressed concerns about the high densities of the species. This study sought to quantify the current abundance and growth of A. dealbata in selected landscapes in the northern Eastern Cape, around nine villages in rural Matatiele, Mount Fletcher and Maclear. Standard vegetation survey techniques were adopted to quantify the density, biomass and growth rate of A. dealbata. Overall, the average density, biomass and productivity of A. dealbata were estimated at approximately 7000 stems ha−1, 12 Mg ha−1 and 4 Mg ha−1 year−1, respectively. However, the abundance and productivity of A. dealbata were spatially variable between study areas. Acacia dealbata stems experienced significant growth over the period of a single year, contributing to substantial biomass production at the landscape level, despite continued harvest. Furthermore, relatively few biophysical variables were significantly influential correlates with the abundance of A. dealbata. Indeed, the degree of biological invasion can be highly variable across the landscape, shaped by the interaction of local-scale biophysical conditions.
- Full Text:
- Date Issued: 2019
Abundance, population structure and harvesting selection of two palm species (Hyphaene coriacea and Phoenix reclinata) in Zitundo area, southern Mozambique
- Martins, Angelina R O, Shackleton, Charlie M
- Authors: Martins, Angelina R O , Shackleton, Charlie M
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182003 , vital:43789 , xlink:href="https://doi.org/10.1016/j.foreco.2017.05.005"
- Description: In southern Mozambique, the sap and leaves of the palms Hyphaene coriacea and Phoenix reclinata are harvested by local people as sources of traditional beverages, weaving, roofing, fencing and furniture material. The harvesting of these palm products may affect palm population structure, dynamics and viability. This work evaluates the abundance, population structure and harvesting selection of these two heavily harvested palm species. Hyphaene coriacea was more abundant, with a mean density of 601.5 ± 455.9 stems ha−1 against the 251.9 ± 527.3 stems ha−1 of Phoenix reclinata. Both species exhibited steeper negative slopes in the regression analyses of the size class distribution, indicating the presence of more individuals in smaller size classes. Although there was a dominance of shorter over taller size classes, limited recruitment was observed through low densities of seedling and juvenile size classes compared to the size class 1–50 cm. The Simpson index of dominance, the permutation index, and the fluctuating quotients between the consecutive size classes showed a degree of instability in both populations. Hyphaene coriacea appears to be more resilient to tapping than Phoenix reclinata, evident in the higher rate of stem survival after tapping. Hyphaene coriacea is favored for tapping compared to Phoenix reclinata. Tappers exhibited positive selection for five out of the six Hyphaene coriacea size classes, against only one Phoenix reclinata size class. The most preferred size class to tap for both species was between 101 cm and 150 cm tall. The instability detected by the indices of population stability, the coincidence between the size classes with high numbers of dead stems and the most preferred and the low level of the sexual reproduction encountered in both population emphasizes the need for long-term monitoring as well as management measures that integrate the resource users, to ensure the long-term sustainability of these populations.
- Full Text:
- Date Issued: 2017
- Authors: Martins, Angelina R O , Shackleton, Charlie M
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182003 , vital:43789 , xlink:href="https://doi.org/10.1016/j.foreco.2017.05.005"
- Description: In southern Mozambique, the sap and leaves of the palms Hyphaene coriacea and Phoenix reclinata are harvested by local people as sources of traditional beverages, weaving, roofing, fencing and furniture material. The harvesting of these palm products may affect palm population structure, dynamics and viability. This work evaluates the abundance, population structure and harvesting selection of these two heavily harvested palm species. Hyphaene coriacea was more abundant, with a mean density of 601.5 ± 455.9 stems ha−1 against the 251.9 ± 527.3 stems ha−1 of Phoenix reclinata. Both species exhibited steeper negative slopes in the regression analyses of the size class distribution, indicating the presence of more individuals in smaller size classes. Although there was a dominance of shorter over taller size classes, limited recruitment was observed through low densities of seedling and juvenile size classes compared to the size class 1–50 cm. The Simpson index of dominance, the permutation index, and the fluctuating quotients between the consecutive size classes showed a degree of instability in both populations. Hyphaene coriacea appears to be more resilient to tapping than Phoenix reclinata, evident in the higher rate of stem survival after tapping. Hyphaene coriacea is favored for tapping compared to Phoenix reclinata. Tappers exhibited positive selection for five out of the six Hyphaene coriacea size classes, against only one Phoenix reclinata size class. The most preferred size class to tap for both species was between 101 cm and 150 cm tall. The instability detected by the indices of population stability, the coincidence between the size classes with high numbers of dead stems and the most preferred and the low level of the sexual reproduction encountered in both population emphasizes the need for long-term monitoring as well as management measures that integrate the resource users, to ensure the long-term sustainability of these populations.
- Full Text:
- Date Issued: 2017
Academic literacy in management education
- Pearse, Noel J, Amos, Trevor L
- Authors: Pearse, Noel J , Amos, Trevor L
- Date: 2000
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/270065 , vital:54392 , xlink:href="https://hdl.handle.net/10520/EJC36783"
- Description: Although management education aims to equip students with relevant knowledge, skills and competencies, making explicit and developing the cognitive thought processes necessary for management students to deal effectively with the current and future demands of the world of work, have been neglected. This article argues for the development of "complicated understanding" (Bartunek, Gordon and Weathersby 1983) in management students, through cultivating academic literacy. Using mediation, reflective inquiry and reflective writing interactively, it is illustrated how academic literacy could be promoted at the post-graduate level.
- Full Text:
- Date Issued: 2000
- Authors: Pearse, Noel J , Amos, Trevor L
- Date: 2000
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/270065 , vital:54392 , xlink:href="https://hdl.handle.net/10520/EJC36783"
- Description: Although management education aims to equip students with relevant knowledge, skills and competencies, making explicit and developing the cognitive thought processes necessary for management students to deal effectively with the current and future demands of the world of work, have been neglected. This article argues for the development of "complicated understanding" (Bartunek, Gordon and Weathersby 1983) in management students, through cultivating academic literacy. Using mediation, reflective inquiry and reflective writing interactively, it is illustrated how academic literacy could be promoted at the post-graduate level.
- Full Text:
- Date Issued: 2000
Academy of Pharmaceutical Sciences
- Authors: Walker, Roderick B
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184768 , vital:44270 , xlink:href="https://hdl.handle.net/10520/EJC-98c37d47c"
- Description: It is an honour and a pleasure to report on the activities of the Academy of Pharmaceutical Sciences since the PSSA AGM in 2016. The Academy of Pharmaceutical Sciences of the Pharmaceutical Society of South Africa (APSSA) held their 37th Annual Conference and 38th Annual General Meeting at the All African Congress on Pharmacology and Pharmacy. The conference was jointly organised by the Academy of Pharmaceutical Sciences of South Africa (APSSA), the South African Society for Basic and Clinical Pharmacology (SASBCP) on behalf of Pharmacology for Africa (Pharfa) and the Toxicology Society of South Africa (ToxSA). The annual APSSA conference was hosted by the Department of Pharmaceutical Sciences, Tshwane University of Technology under the leadership of Dr Ilze Vermaak and was held from 5-8 October 2016 at Misty Hills Conference Centre, situated close to the Cradle of Humankind.
- Full Text:
- Date Issued: 2017
- Authors: Walker, Roderick B
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184768 , vital:44270 , xlink:href="https://hdl.handle.net/10520/EJC-98c37d47c"
- Description: It is an honour and a pleasure to report on the activities of the Academy of Pharmaceutical Sciences since the PSSA AGM in 2016. The Academy of Pharmaceutical Sciences of the Pharmaceutical Society of South Africa (APSSA) held their 37th Annual Conference and 38th Annual General Meeting at the All African Congress on Pharmacology and Pharmacy. The conference was jointly organised by the Academy of Pharmaceutical Sciences of South Africa (APSSA), the South African Society for Basic and Clinical Pharmacology (SASBCP) on behalf of Pharmacology for Africa (Pharfa) and the Toxicology Society of South Africa (ToxSA). The annual APSSA conference was hosted by the Department of Pharmaceutical Sciences, Tshwane University of Technology under the leadership of Dr Ilze Vermaak and was held from 5-8 October 2016 at Misty Hills Conference Centre, situated close to the Cradle of Humankind.
- Full Text:
- Date Issued: 2017
Acetophenone substituted phthalocyanines and their graphene quantum dots conjugates as photosensitizers for photodynamic antimicrobial chemotherapy against Staphylococcus aureus
- Openda, Yolande I, Sen, Pinar, Managa, Muthumuni, Nyokong, Tebello
- Authors: Openda, Yolande I , Sen, Pinar , Managa, Muthumuni , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186507 , vital:44506 , xlink:href="https://doi.org/10.1016/j.pdpdt.2019.101607"
- Description: This work reports on the synthesis and characterization of novel acetophenone substituted phthalocyanines along with the self-assembled nanoconjugates formed via π-π stacking interaction between the synthesized unmetalated (2), zinc (3) and indium (4) phthalocyanines and graphene quantum dots (GQDs) to form 2@GQDs, 3@GQDs and 4@GQDs. The complexes and conjugates exhibited high singlet oxygen ranging from 0.20 to 0.79 in DMSO for Pcs and nanoconjugates where in all cases, the indium complexes showed the highest singlet oxygen quantum yields. The photodynamic antimicrobial chemotherapy activity of both phthalocyanines and nanoconjugates were tested against Staphylococcus aureus. 4@GQDs was found to be highly effective causing a 9.68 log reduction of the bacteria at 10 μM (based on Pc) when compared to 3.77 log reduction of 3@GQDs.
- Full Text:
- Date Issued: 2020
- Authors: Openda, Yolande I , Sen, Pinar , Managa, Muthumuni , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186507 , vital:44506 , xlink:href="https://doi.org/10.1016/j.pdpdt.2019.101607"
- Description: This work reports on the synthesis and characterization of novel acetophenone substituted phthalocyanines along with the self-assembled nanoconjugates formed via π-π stacking interaction between the synthesized unmetalated (2), zinc (3) and indium (4) phthalocyanines and graphene quantum dots (GQDs) to form 2@GQDs, 3@GQDs and 4@GQDs. The complexes and conjugates exhibited high singlet oxygen ranging from 0.20 to 0.79 in DMSO for Pcs and nanoconjugates where in all cases, the indium complexes showed the highest singlet oxygen quantum yields. The photodynamic antimicrobial chemotherapy activity of both phthalocyanines and nanoconjugates were tested against Staphylococcus aureus. 4@GQDs was found to be highly effective causing a 9.68 log reduction of the bacteria at 10 μM (based on Pc) when compared to 3.77 log reduction of 3@GQDs.
- Full Text:
- Date Issued: 2020
Activated carbon-decorated polyacrylonitrile fibers and their porphyrin-immobilized composites for removal of methylene blue dye and Ciprofloxacin in water
- Oyim, James, Amuhaya, Edith, Nyokong, Tebello
- Authors: Oyim, James , Amuhaya, Edith , Nyokong, Tebello
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/${Handle} , vital:65077 , xlink:href="https://doi.org/10.1080/10601325.2023.2183868"
- Description: Photocatalyst adsorbents are an appealing group of materials for environmental applications. Herein, we study a new simple, inexpensive, yet very effective adsorbent photocatalyst based on porphyrin immobilized activated carbon-decorated polyacrylonitrile, InP(PAN/AC), for removal of methylene blue dye and Ciprofloxacin in water under Xe-lamp and sunlight irradiation (the latter for Ciprofloxacin only). Our results shed light on developing the most effective and sustainable adsorbent photocatalysts that can easily be industrialized due to the ease of preparation through electrospinning coupled with the readily available preparation materials. After five cycles, the InP(PAN/AC) maintained high methylene dye removal efficiency and structural integrity. Significantly, we propose the coordinated contribution of singlet oxygen and hydroxyl radical in the photodegradation process and highlight the importance of such an integrated system with adsorption and photodegradation capabilities for water treatment.
- Full Text:
- Date Issued: 2023
- Authors: Oyim, James , Amuhaya, Edith , Nyokong, Tebello
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/${Handle} , vital:65077 , xlink:href="https://doi.org/10.1080/10601325.2023.2183868"
- Description: Photocatalyst adsorbents are an appealing group of materials for environmental applications. Herein, we study a new simple, inexpensive, yet very effective adsorbent photocatalyst based on porphyrin immobilized activated carbon-decorated polyacrylonitrile, InP(PAN/AC), for removal of methylene blue dye and Ciprofloxacin in water under Xe-lamp and sunlight irradiation (the latter for Ciprofloxacin only). Our results shed light on developing the most effective and sustainable adsorbent photocatalysts that can easily be industrialized due to the ease of preparation through electrospinning coupled with the readily available preparation materials. After five cycles, the InP(PAN/AC) maintained high methylene dye removal efficiency and structural integrity. Significantly, we propose the coordinated contribution of singlet oxygen and hydroxyl radical in the photodegradation process and highlight the importance of such an integrated system with adsorption and photodegradation capabilities for water treatment.
- Full Text:
- Date Issued: 2023
Active learning in schools
- Lotz-Sisitka, Heila, Timmermans, Ingrid
- Authors: Lotz-Sisitka, Heila , Timmermans, Ingrid
- Date: 2001
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/389696 , vital:68475 , xlink:href="https://eeasa.org.za/wp-content/uploads/2016/12/Bulletin_vol21-_Sep-2001.pdf"
- Description: The Rhodes University Environmental Education Unit has initiated a project to support school-based environmental education work in Grahamstown. In line with national environmental education policy, the project supports a focus on environmental learning in the context of the OBE curriculum, and provides professional development support to teachers implementing the project (NEEP, 2000). An action research evaluation is taking place to monitor key aspects of the project and a number of interim evaluation reports have been produced (Mbanjwa, 2001).
- Full Text:
- Date Issued: 2001
- Authors: Lotz-Sisitka, Heila , Timmermans, Ingrid
- Date: 2001
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/389696 , vital:68475 , xlink:href="https://eeasa.org.za/wp-content/uploads/2016/12/Bulletin_vol21-_Sep-2001.pdf"
- Description: The Rhodes University Environmental Education Unit has initiated a project to support school-based environmental education work in Grahamstown. In line with national environmental education policy, the project supports a focus on environmental learning in the context of the OBE curriculum, and provides professional development support to teachers implementing the project (NEEP, 2000). An action research evaluation is taking place to monitor key aspects of the project and a number of interim evaluation reports have been produced (Mbanjwa, 2001).
- Full Text:
- Date Issued: 2001
Actor/actant-network theory as emerging methodology for environmental education research in southern Africa
- Authors: Nhamo, Godwell
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/373553 , vital:66701 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122722"
- Description: This paper deliberates on actor/actant-network theory (AANT) as methodology for policy research in environmental education (EE). Insights are drawn from work that applied AANT to research environmental policy processes surrounding the formulation and implementation of South Africa’s Plastic Bags Regulations of 2003. The paper reveals that the application of AANT methodology made it possible to trace relationships, actors, actants and actor/actant-networks surrounding the Plastic Bags Regulations as quasi-object (token). The methodology also enabled a focus on understanding and investigating tensions, debates and responses emerging from the policy process. The findings were that after the promulgation of the first draft of the Plastic Bags Regulations in May 2000, tensions emerged around the nature of regulation (whether to use the command and control approach – preferred by Organised Government – or self regulation – preferred by Organised Business and Organised Labour). From these findings, a series of conceptual frameworks were drawn up as identified around key actors and actor/actant-networks. The conceptual frameworks included among them, Organised Government, Organised Business and Organised Labour.
- Full Text: false
- Date Issued: 2006
- Authors: Nhamo, Godwell
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/373553 , vital:66701 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122722"
- Description: This paper deliberates on actor/actant-network theory (AANT) as methodology for policy research in environmental education (EE). Insights are drawn from work that applied AANT to research environmental policy processes surrounding the formulation and implementation of South Africa’s Plastic Bags Regulations of 2003. The paper reveals that the application of AANT methodology made it possible to trace relationships, actors, actants and actor/actant-networks surrounding the Plastic Bags Regulations as quasi-object (token). The methodology also enabled a focus on understanding and investigating tensions, debates and responses emerging from the policy process. The findings were that after the promulgation of the first draft of the Plastic Bags Regulations in May 2000, tensions emerged around the nature of regulation (whether to use the command and control approach – preferred by Organised Government – or self regulation – preferred by Organised Business and Organised Labour). From these findings, a series of conceptual frameworks were drawn up as identified around key actors and actor/actant-networks. The conceptual frameworks included among them, Organised Government, Organised Business and Organised Labour.
- Full Text: false
- Date Issued: 2006