SOA driven architectures for service creation through enablers in an IMS testbed
- Tsietsi, Mosiuoa, Terzoli, Alfredo, Wells,George C
- Authors: Tsietsi, Mosiuoa , Terzoli, Alfredo , Wells,George C
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430726 , vital:72711 , https://ieeexplore.ieee.org/abstract/document/6144230
- Description: Standards development organisations have long been in agreement that the most appropriate and cost effective way of developing services for the IP Multimedia Subsystem (IMS) is through the use - and re-use - of service capabilities, which are the building blocks for developing complex services. IMS specifications provide a theoretical framework for how service capabilities can be aggregated into large service appli-cations. However, there is little evidence that mainstream IMS service development is capability-based, and many services are still designed in a monolithic way, with no re-use of existing functionality. Telecom-munication networks are well positioned to stimulate the Internet ser-vices market by exposing these service enablers to third parties. In this paper, we marry the two issues by defining an extended IMS service layer (EISL) that provides a service broker that is the central agent in both service interaction management and the execution of external re-quests from third parties. A prototypical implementation of the service broker is described that was developed using a converged SIP servlet container, and a discussion is also provided that details how third party developers could use HTTP APIs to interact with a service broker in or-der to gain access to network capabilities.
- Full Text:
- Authors: Tsietsi, Mosiuoa , Terzoli, Alfredo , Wells,George C
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430726 , vital:72711 , https://ieeexplore.ieee.org/abstract/document/6144230
- Description: Standards development organisations have long been in agreement that the most appropriate and cost effective way of developing services for the IP Multimedia Subsystem (IMS) is through the use - and re-use - of service capabilities, which are the building blocks for developing complex services. IMS specifications provide a theoretical framework for how service capabilities can be aggregated into large service appli-cations. However, there is little evidence that mainstream IMS service development is capability-based, and many services are still designed in a monolithic way, with no re-use of existing functionality. Telecom-munication networks are well positioned to stimulate the Internet ser-vices market by exposing these service enablers to third parties. In this paper, we marry the two issues by defining an extended IMS service layer (EISL) that provides a service broker that is the central agent in both service interaction management and the execution of external re-quests from third parties. A prototypical implementation of the service broker is described that was developed using a converged SIP servlet container, and a discussion is also provided that details how third party developers could use HTTP APIs to interact with a service broker in or-der to gain access to network capabilities.
- Full Text:
South Africa’s Abortion Values Clarification Workshops: an opportunity to deepen democratic communication missed
- Authors: Vincent, Louise
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141981 , vital:38021 , DOI: 10.1177/0021909610396161
- Description: A rich literature exists on local democracy and participation in South Africa. While the importance of participation is routinely built into the rhetoric of government, debate has increasingly focused on the dysfunctionality of participatory mechanisms and institutions in post-apartheid South Africa. Processes aimed ostensibly at empowering citizens, act in practice as instruments of social control, disempowerment and cooptation. The present article contributes to these debates by way of a critique of the approach used by the South African state, in partnership with the non-governmental sector, in what are called abortion ‘values clarification’ (VC) workshops. This article examines the workshop materials, methodology and pedagogical tools employed in South African abortion VC workshops which emanate from the organization Ipas — a global body working to enhance women’s sexual and reproductive rights and to reduce abortion-related deaths and injuries. VC workshops represent an instance of a more general trend in which participation is seen as a tool for generating legitimacy and ‘buy-in’ for central state directives rather than as a means for genuinely deepening democratic communication.
- Full Text:
- Authors: Vincent, Louise
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141981 , vital:38021 , DOI: 10.1177/0021909610396161
- Description: A rich literature exists on local democracy and participation in South Africa. While the importance of participation is routinely built into the rhetoric of government, debate has increasingly focused on the dysfunctionality of participatory mechanisms and institutions in post-apartheid South Africa. Processes aimed ostensibly at empowering citizens, act in practice as instruments of social control, disempowerment and cooptation. The present article contributes to these debates by way of a critique of the approach used by the South African state, in partnership with the non-governmental sector, in what are called abortion ‘values clarification’ (VC) workshops. This article examines the workshop materials, methodology and pedagogical tools employed in South African abortion VC workshops which emanate from the organization Ipas — a global body working to enhance women’s sexual and reproductive rights and to reduce abortion-related deaths and injuries. VC workshops represent an instance of a more general trend in which participation is seen as a tool for generating legitimacy and ‘buy-in’ for central state directives rather than as a means for genuinely deepening democratic communication.
- Full Text:
Stable isotope methods: the effect of gut contents on isotopic ratios of zooplankton
- Hill, Jaclyn M, McQuaid, Christopher D
- Authors: Hill, Jaclyn M , McQuaid, Christopher D
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444623 , vital:74255 , https://doi.org/10.1016/j.ecss.2011.02.002
- Description: In the past decade there has been an increased awareness of the potential for methodological bias resulting from multiple pre-analytical procedures in foodweb interpretations based on stable isotope techniques. In the case of small organisms, this includes the effect of gut contents on whole body signatures. Although gut contents may not reflect actual assimilation, their carbon and nitrogen values will be isotopically lighter than after the same material has been assimilated. The potential skewing of isotopic ratios in whole organism samples is especially important for aquatic environments as many studies involve trophic relationships among small zooplankton. This is particularly important in pelagic waters, where herbivorous zooplankton comprise small taxa. Hence this study investigated the effect of gut contents on the δ13C and δ15N ratios of three size classes of zooplankton (1.0–2.0, 2.0–4.0 and >4.0mm) collected using bongo net tows in the tropical waters of the south-west Indian Ocean. Animals were collected at night, when they were likely to be feeding, sieved into size classes and separated into genera. We focused on Euphausia spp which dominated zooplankton biomass. Three treatment types were processed: bulk animals, bulk animals without guts and tail muscle from each size class at 10 bongo stations.
- Full Text:
- Authors: Hill, Jaclyn M , McQuaid, Christopher D
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444623 , vital:74255 , https://doi.org/10.1016/j.ecss.2011.02.002
- Description: In the past decade there has been an increased awareness of the potential for methodological bias resulting from multiple pre-analytical procedures in foodweb interpretations based on stable isotope techniques. In the case of small organisms, this includes the effect of gut contents on whole body signatures. Although gut contents may not reflect actual assimilation, their carbon and nitrogen values will be isotopically lighter than after the same material has been assimilated. The potential skewing of isotopic ratios in whole organism samples is especially important for aquatic environments as many studies involve trophic relationships among small zooplankton. This is particularly important in pelagic waters, where herbivorous zooplankton comprise small taxa. Hence this study investigated the effect of gut contents on the δ13C and δ15N ratios of three size classes of zooplankton (1.0–2.0, 2.0–4.0 and >4.0mm) collected using bongo net tows in the tropical waters of the south-west Indian Ocean. Animals were collected at night, when they were likely to be feeding, sieved into size classes and separated into genera. We focused on Euphausia spp which dominated zooplankton biomass. Three treatment types were processed: bulk animals, bulk animals without guts and tail muscle from each size class at 10 bongo stations.
- Full Text:
Study of protein complexes via homology modeling, applied to cysteine proteases and their protein inhibitors:
- Tastan Bishop, Özlem, Kroon, Matthys
- Authors: Tastan Bishop, Özlem , Kroon, Matthys
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148070 , vital:38707 , DOI: 10.1007/s00894-011-0990-y
- Description: This paper develops and evaluates large-scale calculation of 3D structures of protein complexes by homology modeling as a promising new approach for protein docking. The complexes investigated were papain-like cysteine proteases and their protein inhibitors, which play numerous roles in human and parasitic metabolisms. The structural modeling was performed in two parts. For the first part (evaluation set), nine crystal structure complexes were selected, 1325 homology models of known complexes were rebuilt by various templates including hybrids, allowing an analysis of the factors influencing the accuracy of the models. The important considerations for modeling the interface were protease coverage and inhibitor sequence identity. In the second part (study set), the findings of the evaluation set were used to select appropriate templates to model novel cysteine protease-inhibitor complexes from human and malaria parasites Plasmodium falciparum and Plasmodium vivax. The energy scores, considering the evaluation set, indicate that the models are of high accuracy.
- Full Text:
- Authors: Tastan Bishop, Özlem , Kroon, Matthys
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148070 , vital:38707 , DOI: 10.1007/s00894-011-0990-y
- Description: This paper develops and evaluates large-scale calculation of 3D structures of protein complexes by homology modeling as a promising new approach for protein docking. The complexes investigated were papain-like cysteine proteases and their protein inhibitors, which play numerous roles in human and parasitic metabolisms. The structural modeling was performed in two parts. For the first part (evaluation set), nine crystal structure complexes were selected, 1325 homology models of known complexes were rebuilt by various templates including hybrids, allowing an analysis of the factors influencing the accuracy of the models. The important considerations for modeling the interface were protease coverage and inhibitor sequence identity. In the second part (study set), the findings of the evaluation set were used to select appropriate templates to model novel cysteine protease-inhibitor complexes from human and malaria parasites Plasmodium falciparum and Plasmodium vivax. The energy scores, considering the evaluation set, indicate that the models are of high accuracy.
- Full Text:
Study South Africa
- International Education Association of South Africa (IEASA), Jooste, Nico
- Authors: International Education Association of South Africa (IEASA) , Jooste, Nico
- Date: 2011
- Subjects: Education, Higher -- South Africa , Universities and colleges -- South Africa , Technical Institutes -- South Africa , Vocational guidance -- South Africa
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/64952 , vital:28639 , ISBN 9780620512244
- Description: [Extract from article by Ms Merle Hodges]: Over the past year there have been numerous conferences dealing with one general topic. How is it possible for higher education, globally, to produce the same quality in its graduates, research and community outreach when the financial resources entering into the system are radically declining? The conclusion is overwhelmingly despondent. ‘Universities have to do more with less, academics and academic research will increasingly be pressurised by lower salaries internally and career temptations from the corporate world – the impact of which is the greater commodification of universities, and the inevitable decline in academic freedom.’ This global negativity is predicated on inter–related factors. The first, the long tail of the economic recession, is continuing to bite all sectors and higher education is no exception. Secondly, higher education is a little like marketing – when the pressure is on government, sectors like higher education are de–prioritised. In light of this, the position of internationalisation in higher education might seem to fade into the background. Interestingly, the inverse is true. While the zeitgeist of higher education generally appears dismal, the prospects of internationalisation appear rosy in comparison. I believe this is true because of two overlapping issues. Firstly, students are not going to give up on university because of a lingering economic downturn. What they are doing, however, is deciding to travel and study at destinations that would have been perceived as implausible a few years ago. Venezuela, Chile, South Korea and South Africa are all drawing US students more than ever before. This is partly because, I sense, the quality of qualifications is achieving parity across the globe; and also, because students who are prepared to travel realise that cultural specificity – the ability to learn new and unique aspects of a different culture while gaining the same core ingredients of a degree – sets it apart from the degree gained locally. A one semester course in Russian anthropology might appear entirely redundant when applying for a job. However, the very interconnectedness of global business means not only that the course is never a waste of time, but that it might mean the difference between landing a contract and failing to do so. The international student has the benefit of developing in ways that traditional (home-grown) higher education may not yet fully understand. Secondly, development in South Africa at least, has an additional meaning. Our universities are not only focused on developing graduates for multicultural or global competitiveness. Over the past five or so years our universities have been focused on development of the country itself. As an emerging power, the impetus has been on creating universities that address the fundamental needs of the people. Poverty, HIV, sustainability and innovative solutions to global problems are the very sap of South African universities in the 21st Century. How to create a sustainable environment, how to preserve marine and wildlife, how to create jobs, reduce poverty, and maximise innovation – these are the concerns that are preoccupying the minds of the country’s best academics. , 11th Edition
- Full Text:
- Authors: International Education Association of South Africa (IEASA) , Jooste, Nico
- Date: 2011
- Subjects: Education, Higher -- South Africa , Universities and colleges -- South Africa , Technical Institutes -- South Africa , Vocational guidance -- South Africa
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/64952 , vital:28639 , ISBN 9780620512244
- Description: [Extract from article by Ms Merle Hodges]: Over the past year there have been numerous conferences dealing with one general topic. How is it possible for higher education, globally, to produce the same quality in its graduates, research and community outreach when the financial resources entering into the system are radically declining? The conclusion is overwhelmingly despondent. ‘Universities have to do more with less, academics and academic research will increasingly be pressurised by lower salaries internally and career temptations from the corporate world – the impact of which is the greater commodification of universities, and the inevitable decline in academic freedom.’ This global negativity is predicated on inter–related factors. The first, the long tail of the economic recession, is continuing to bite all sectors and higher education is no exception. Secondly, higher education is a little like marketing – when the pressure is on government, sectors like higher education are de–prioritised. In light of this, the position of internationalisation in higher education might seem to fade into the background. Interestingly, the inverse is true. While the zeitgeist of higher education generally appears dismal, the prospects of internationalisation appear rosy in comparison. I believe this is true because of two overlapping issues. Firstly, students are not going to give up on university because of a lingering economic downturn. What they are doing, however, is deciding to travel and study at destinations that would have been perceived as implausible a few years ago. Venezuela, Chile, South Korea and South Africa are all drawing US students more than ever before. This is partly because, I sense, the quality of qualifications is achieving parity across the globe; and also, because students who are prepared to travel realise that cultural specificity – the ability to learn new and unique aspects of a different culture while gaining the same core ingredients of a degree – sets it apart from the degree gained locally. A one semester course in Russian anthropology might appear entirely redundant when applying for a job. However, the very interconnectedness of global business means not only that the course is never a waste of time, but that it might mean the difference between landing a contract and failing to do so. The international student has the benefit of developing in ways that traditional (home-grown) higher education may not yet fully understand. Secondly, development in South Africa at least, has an additional meaning. Our universities are not only focused on developing graduates for multicultural or global competitiveness. Over the past five or so years our universities have been focused on development of the country itself. As an emerging power, the impetus has been on creating universities that address the fundamental needs of the people. Poverty, HIV, sustainability and innovative solutions to global problems are the very sap of South African universities in the 21st Century. How to create a sustainable environment, how to preserve marine and wildlife, how to create jobs, reduce poverty, and maximise innovation – these are the concerns that are preoccupying the minds of the country’s best academics. , 11th Edition
- Full Text:
Syntheses and electrochemical characterization of new water soluble octaarylthiosubstituted manganese phthalocyanines
- Booysen, Irvin N, Matemadombo, Fungisai, Durmus, Mahmut, Nyokong, Tebello
- Authors: Booysen, Irvin N , Matemadombo, Fungisai , Durmus, Mahmut , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247614 , vital:51600 , xlink:href="https://doi.org/10.1016/j.dyepig.2010.09.012"
- Description: This paper reports on the synthesis and characterization of new manganese phthalocyanine (MnPc) complexes: 2,3-octakis-[(2-mercaptopyridine) phthalocyaninato] acetato manganese (III) (1) and its quaternized (hence water soluble) derivative: 2,3-octakis-{[(N-methyl-2-mercaptopyridine) phthalocyaninato] acetato manganese (III)} sulphate (2). The complexes were used to form self assembled monolayers (SAMs). Voltammetry proved that both of the SAMs are well packed, strongly passivating and act as selective and efficient barriers to ion permeability. Furthermore, surface coverage studies confirmed that the MPc macrocycles adsorb onto the gold electrode as monolayers. Both MPc SAMs were successfully used as electrochemical sensors of nitrite.
- Full Text:
- Authors: Booysen, Irvin N , Matemadombo, Fungisai , Durmus, Mahmut , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247614 , vital:51600 , xlink:href="https://doi.org/10.1016/j.dyepig.2010.09.012"
- Description: This paper reports on the synthesis and characterization of new manganese phthalocyanine (MnPc) complexes: 2,3-octakis-[(2-mercaptopyridine) phthalocyaninato] acetato manganese (III) (1) and its quaternized (hence water soluble) derivative: 2,3-octakis-{[(N-methyl-2-mercaptopyridine) phthalocyaninato] acetato manganese (III)} sulphate (2). The complexes were used to form self assembled monolayers (SAMs). Voltammetry proved that both of the SAMs are well packed, strongly passivating and act as selective and efficient barriers to ion permeability. Furthermore, surface coverage studies confirmed that the MPc macrocycles adsorb onto the gold electrode as monolayers. Both MPc SAMs were successfully used as electrochemical sensors of nitrite.
- Full Text:
Syntheses, electrochemical and spectroelectrochemical properties of novel ball-type and mononuclear Co (II) phthalocyanines substituted at the peripheral and non-peripheral positions with binaphthol groups
- Canlıca, Mevlüde, Booysen, Irvin Noel, Nyokong, Tebello
- Authors: Canlıca, Mevlüde , Booysen, Irvin Noel , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247837 , vital:51622 , xlink:href="https://doi.org/10.1016/j.poly.2010.11.017"
- Description: Mononuclear cobalt phthalocyanine (CoPc) substituted at the non-peripheral 8 and peripheral positions 9 with 1,1′-binaphthyl-8,8′-diol and ball-type dinuclear Co2Pc2 substituted at the non-peripheral 10 and peripheral 11 positions with the same substituent are reported. The complexes with 1,1′-binaphthol-bridges were prepared from the corresponding phthalonitriles 4–7. The effects of the position of substituent on spectral, electrochemical and spectroelectrochemical properties of these complexes were also explored. The mononuclear complexes 8 and 9 exhibited one metal reduction, one ring reduction and one ring oxidation. The redox properties of the ball-type complexes 10 and 11 exhibited two reduction processes assigned to [(CoIPc−2)2]2−/[(CoIPc−3)2]4− (I), (CoIIPc−2)2/[(CoIPc−2)2]2− (II) and one oxidation process assigned to [(CoIIIPc−2)2]2+/CoIIPc−2)2 (III). The ball-type complexes are much easier to oxidize and more difficult to reduce than the corresponding monomers 8 and 9.
- Full Text:
- Authors: Canlıca, Mevlüde , Booysen, Irvin Noel , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247837 , vital:51622 , xlink:href="https://doi.org/10.1016/j.poly.2010.11.017"
- Description: Mononuclear cobalt phthalocyanine (CoPc) substituted at the non-peripheral 8 and peripheral positions 9 with 1,1′-binaphthyl-8,8′-diol and ball-type dinuclear Co2Pc2 substituted at the non-peripheral 10 and peripheral 11 positions with the same substituent are reported. The complexes with 1,1′-binaphthol-bridges were prepared from the corresponding phthalonitriles 4–7. The effects of the position of substituent on spectral, electrochemical and spectroelectrochemical properties of these complexes were also explored. The mononuclear complexes 8 and 9 exhibited one metal reduction, one ring reduction and one ring oxidation. The redox properties of the ball-type complexes 10 and 11 exhibited two reduction processes assigned to [(CoIPc−2)2]2−/[(CoIPc−3)2]4− (I), (CoIIPc−2)2/[(CoIPc−2)2]2− (II) and one oxidation process assigned to [(CoIIIPc−2)2]2+/CoIIPc−2)2 (III). The ball-type complexes are much easier to oxidize and more difficult to reduce than the corresponding monomers 8 and 9.
- Full Text:
Synthesis and electrocatalytic behavior of cobalt (II)-tris (benzyl-mercapto)-monoaminophthalocyanine–single walled carbon nanotube nanorods
- Mugadza, Tawanda, Nyokong, Tebello
- Authors: Mugadza, Tawanda , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247882 , vital:51626 , xlink:href="https://doi.org/10.1016/j.electacta.2010.11.016"
- Description: In this paper we report on synthesis and electrocatalytic behavior of cobalt (II)-tris(benzyl-mercapto)-monoaminophthalocyanine–single walled carbon nanotube nanorods towards the oxidation of amitrole. SWCNTs that were terminally functionalized with carboxylic acid groups were chemically linked to cobalt (II)-tris(benzyl-mercapto) monoaminophthalocyanine (CoMAPc) via an amide bond to form nanorods. UV–vis, FTIR, TEM, Raman and XRD spectroscopies were used in characterization of the nanorods (CoMAPc–SWCNT-linked), while cyclic voltammetry and chronoamperometry were used during the characterization of amitrole on the modified glassy carbon electrode. The linear dynamic range for the amitrole was from 1.0 × 10−6 M to 1.2 × 10−4 M, with a sensitivity of 6.76 A mol−1 L cm−2. The estimated limit of detection for amitrole was 0.10 μM, using the 3δ criterion. The catalytic rate constant was found to be 1.09 × 105 M−1 s−1.
- Full Text:
- Authors: Mugadza, Tawanda , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247882 , vital:51626 , xlink:href="https://doi.org/10.1016/j.electacta.2010.11.016"
- Description: In this paper we report on synthesis and electrocatalytic behavior of cobalt (II)-tris(benzyl-mercapto)-monoaminophthalocyanine–single walled carbon nanotube nanorods towards the oxidation of amitrole. SWCNTs that were terminally functionalized with carboxylic acid groups were chemically linked to cobalt (II)-tris(benzyl-mercapto) monoaminophthalocyanine (CoMAPc) via an amide bond to form nanorods. UV–vis, FTIR, TEM, Raman and XRD spectroscopies were used in characterization of the nanorods (CoMAPc–SWCNT-linked), while cyclic voltammetry and chronoamperometry were used during the characterization of amitrole on the modified glassy carbon electrode. The linear dynamic range for the amitrole was from 1.0 × 10−6 M to 1.2 × 10−4 M, with a sensitivity of 6.76 A mol−1 L cm−2. The estimated limit of detection for amitrole was 0.10 μM, using the 3δ criterion. The catalytic rate constant was found to be 1.09 × 105 M−1 s−1.
- Full Text:
Synthesis and electrochemical behavior of novel peripherally and non-peripherally substituted ball-type cobalt phthalocyanine complexes
- Canlıca, Mevlüde, Booysen, Irvin Noel, Nyokong, Tebello
- Authors: Canlıca, Mevlüde , Booysen, Irvin Noel , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247848 , vital:51623 , xlink:href="https://doi.org/10.1016/j.poly.2010.11.028"
- Description: The syntheses of new ball-type Co(II) phthalocyanines containing 4,4′-(9H-fluorene-9,9-diyl)diphenol substituents at non-peripheral (complex 6) and peripheral (complex 7) positions are presented. These complexes were characterized by UV–Vis, FT-IR, mass spectroscopy and electrochemical methods. Both complexes exhibit metal and ring based redox processes, typical of cobalt phthalocyanine complexes. For 6, the metal based reduction was observed at −0.46 V followed by a ring based reduction at −1.40 V. The metal oxidation for 6 was observed at +0.16 V and the ring based oxidation at +1.05 V. For 7, reductions are easier but the oxidations are more difficult. The metal based reduction for 7 was observed at −0.38 V followed by a ring based reduction at −1.03 V. The metal oxidation for 7 was observed at +0.20 V and the ring based oxidation at +1.35 V.
- Full Text:
- Authors: Canlıca, Mevlüde , Booysen, Irvin Noel , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247848 , vital:51623 , xlink:href="https://doi.org/10.1016/j.poly.2010.11.028"
- Description: The syntheses of new ball-type Co(II) phthalocyanines containing 4,4′-(9H-fluorene-9,9-diyl)diphenol substituents at non-peripheral (complex 6) and peripheral (complex 7) positions are presented. These complexes were characterized by UV–Vis, FT-IR, mass spectroscopy and electrochemical methods. Both complexes exhibit metal and ring based redox processes, typical of cobalt phthalocyanine complexes. For 6, the metal based reduction was observed at −0.46 V followed by a ring based reduction at −1.40 V. The metal oxidation for 6 was observed at +0.16 V and the ring based oxidation at +1.05 V. For 7, reductions are easier but the oxidations are more difficult. The metal based reduction for 7 was observed at −0.38 V followed by a ring based reduction at −1.03 V. The metal oxidation for 7 was observed at +0.20 V and the ring based oxidation at +1.35 V.
- Full Text:
Synthesis and electrochemical properties of new tetra substituted cobalt phthalocyanine complexes, and their application in electrode modification for the electrocatalysis of l-cysteine
- Erdoğmuş, Ali, Booysen, Irvin Noel, Nyokong, Tebello
- Authors: Erdoğmuş, Ali , Booysen, Irvin Noel , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247893 , vital:51627 , xlink:href="https://doi.org/10.1016/j.synthmet.2010.11.028"
- Description: This study investigates the synthesis and characterization new peripherally (β) tetra-substituted 4-(2-mercaptoquinoline phthalocyaninato) Co(II) (CoPcSHQn, 3), and 4-(2-phenoxy-4-trifluoromethylpyridine phthalocyaninato) Co(II) (CoPcOHPy, 4). These complexes were characterized by elemental analysis, IR, mass and electronic spectroscopies and electrochemical methods. Both complexes show well resolved redox peaks attributed to both ring and metal based processes. Spectroelectrochemistry was used to confirm the assignments of the redox processes. For CoPcSHQn (3): CoIPc−2/CoIPc−3 (E1/2 = −1.25 V, I), CoIIPc−2/CoIPc−2 (E1/2 = −0.57 V, II), CoIIIPc−2/CoIIPc−2 (E1/2 = +0.45 V, IV) and an irreversible process at Ep = +1.05 V vs Ag|AgCl for CoIIIPc−1/CoIIIPc−2 (V). Redox couple III at E1/2 = −0.15 V was ascribed to aggregation. In the case of CoPcOHPy (4): CoIPc−2/CoIPc−3 (E1/2 = −1.13 V, I), CoIIPc−2/CoIPc−2 (E1/2 = −0.45 V, II), CoIIIPc−2/CoIIPc−2 at E1/2 = +0.21 V (IV), and CoIIIPc−1/CoIIIPc−2 (E1/2 = +1.01 V vs Ag|AgCl, V). Again III is associated with the aggregated species. Both complexes were electrodeposited on a glassy carbon electrode (GCE). For complex 3 self-assembled monolayers was also formed. The modified (CoPc-GCE) electrodes electrocatalytically detected L-cysteine at Ep = 0.62 V (3-GCE) and 0.59 V (4-GCE) vs Ag|AgCl.
- Full Text:
- Authors: Erdoğmuş, Ali , Booysen, Irvin Noel , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247893 , vital:51627 , xlink:href="https://doi.org/10.1016/j.synthmet.2010.11.028"
- Description: This study investigates the synthesis and characterization new peripherally (β) tetra-substituted 4-(2-mercaptoquinoline phthalocyaninato) Co(II) (CoPcSHQn, 3), and 4-(2-phenoxy-4-trifluoromethylpyridine phthalocyaninato) Co(II) (CoPcOHPy, 4). These complexes were characterized by elemental analysis, IR, mass and electronic spectroscopies and electrochemical methods. Both complexes show well resolved redox peaks attributed to both ring and metal based processes. Spectroelectrochemistry was used to confirm the assignments of the redox processes. For CoPcSHQn (3): CoIPc−2/CoIPc−3 (E1/2 = −1.25 V, I), CoIIPc−2/CoIPc−2 (E1/2 = −0.57 V, II), CoIIIPc−2/CoIIPc−2 (E1/2 = +0.45 V, IV) and an irreversible process at Ep = +1.05 V vs Ag|AgCl for CoIIIPc−1/CoIIIPc−2 (V). Redox couple III at E1/2 = −0.15 V was ascribed to aggregation. In the case of CoPcOHPy (4): CoIPc−2/CoIPc−3 (E1/2 = −1.13 V, I), CoIIPc−2/CoIPc−2 (E1/2 = −0.45 V, II), CoIIIPc−2/CoIIPc−2 at E1/2 = +0.21 V (IV), and CoIIIPc−1/CoIIIPc−2 (E1/2 = +1.01 V vs Ag|AgCl, V). Again III is associated with the aggregated species. Both complexes were electrodeposited on a glassy carbon electrode (GCE). For complex 3 self-assembled monolayers was also formed. The modified (CoPc-GCE) electrodes electrocatalytically detected L-cysteine at Ep = 0.62 V (3-GCE) and 0.59 V (4-GCE) vs Ag|AgCl.
- Full Text:
Synthesis and photophysical behaviour of tantalum and titanium phthalocyanines in the presence of gold nanoparticles
- Chauke, Vongani P, Arslanoglu, Yasin, Nyokong, Tebello
- Authors: Chauke, Vongani P , Arslanoglu, Yasin , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247545 , vital:51593 , xlink:href="https://doi.org/10.1016/j.jphotochem.2011.04.020"
- Description: We report on the synthesis of 2,(3)- (peripheral) and 1,(4)- (non-peripheral) (2-mercaptopyridine)phthalocyanine complexes of titanium (IV) oxide (5 and 6 respectively), and tantalum (III) hydroxide (7, peripheral only), their photochemical and photophysical parameters and the photocatalytic oxidation of cyclohexene in the presence of gold nanoparticles (AuNPs). The singlet oxygen quantum yield values increased in the presence of AuNPs, for complexes 5 and 6. The percentage conversion values for cyclohexene using 5, 6 and 7 were 27%, 20% and 14%, respectively. These values increased considerably in the presence of AuNPs, except complex for 7. The products obtained include cyclohexene oxide, 2-cyclohexen-1-ol, 2-cyclohexene-1-one and 1,2-cyclohexanediol. Low values of singlet oxygen quantum yields favour the formation of 1,2-cyclohexanediol.
- Full Text:
- Authors: Chauke, Vongani P , Arslanoglu, Yasin , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247545 , vital:51593 , xlink:href="https://doi.org/10.1016/j.jphotochem.2011.04.020"
- Description: We report on the synthesis of 2,(3)- (peripheral) and 1,(4)- (non-peripheral) (2-mercaptopyridine)phthalocyanine complexes of titanium (IV) oxide (5 and 6 respectively), and tantalum (III) hydroxide (7, peripheral only), their photochemical and photophysical parameters and the photocatalytic oxidation of cyclohexene in the presence of gold nanoparticles (AuNPs). The singlet oxygen quantum yield values increased in the presence of AuNPs, for complexes 5 and 6. The percentage conversion values for cyclohexene using 5, 6 and 7 were 27%, 20% and 14%, respectively. These values increased considerably in the presence of AuNPs, except complex for 7. The products obtained include cyclohexene oxide, 2-cyclohexen-1-ol, 2-cyclohexene-1-one and 1,2-cyclohexanediol. Low values of singlet oxygen quantum yields favour the formation of 1,2-cyclohexanediol.
- Full Text:
Synthesis and photophysical properties of a novel zinc photosensitizer and its gold nanoparticle conjugate
- Moeno, Sharon, Antunes, Edith M, Nyokong, Tebello
- Authors: Moeno, Sharon , Antunes, Edith M , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247100 , vital:51546 , xlink:href="https://doi.org/10.1016/j.jphotochem.2011.07.007"
- Description: The peripherally tetra substituted zinc phthalocyanine with 1,6-hexanedithiol as substituent (THdTZnPc, 3) was synthesized and is reported for the first time in this work. The potential of this zinc complex as a suitable photosensitizer for use in photodynamic therapy was determined through the investigation of the photophysical and photochemical properties. In this work complex 3 is attached to gold nanoparticles through the terminal thiol groups of the phthalocyanine resulting in a 3-AuNP conjugate whose photophysicochemical properties are investigated. Fluorescence lifetimes were determined using time correlated single photon counting and they show an increase in the abundance of the monomeric species (τ2) for the Pc in the 3-AuNP conjugate: ∼1 and 0.71 (with respective lifetimes 2.69 ns and 2.86 ns) compared to the free complex 3 with abundances of 0.12 and 0.13 (with respective lifetimes 3.36 ns and 3.28 ns) in DMSO and DMF, respectively.
- Full Text:
- Authors: Moeno, Sharon , Antunes, Edith M , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247100 , vital:51546 , xlink:href="https://doi.org/10.1016/j.jphotochem.2011.07.007"
- Description: The peripherally tetra substituted zinc phthalocyanine with 1,6-hexanedithiol as substituent (THdTZnPc, 3) was synthesized and is reported for the first time in this work. The potential of this zinc complex as a suitable photosensitizer for use in photodynamic therapy was determined through the investigation of the photophysical and photochemical properties. In this work complex 3 is attached to gold nanoparticles through the terminal thiol groups of the phthalocyanine resulting in a 3-AuNP conjugate whose photophysicochemical properties are investigated. Fluorescence lifetimes were determined using time correlated single photon counting and they show an increase in the abundance of the monomeric species (τ2) for the Pc in the 3-AuNP conjugate: ∼1 and 0.71 (with respective lifetimes 2.69 ns and 2.86 ns) compared to the free complex 3 with abundances of 0.12 and 0.13 (with respective lifetimes 3.36 ns and 3.28 ns) in DMSO and DMF, respectively.
- Full Text:
Synthesis and photophysical studies of CdTe quantum dot-monosubstituted zinc phthalocyanine conjugates
- D'Souza, Sarah, Antunes, Edith M, Nyokong, Tebello
- Authors: D'Souza, Sarah , Antunes, Edith M , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247825 , vital:51621 , xlink:href="https://doi.org/10.1016/j.ica.2010.12.027"
- Description: The linkage of unsymmetrically monosubstituted 4-aminophenoxy zinc phthalocyanine (ZnAPPc, 5) to CdTe quantum dots capped with mercaptopropionic acid (MPA), L-cysteine (L-cys) or thioglycolic acid (TGA) has been achieved using the coupling agents ethyl-N(3-dimethylaminopropyl) carbodiimide and N-hydroxy succinimide, which facilitate formation of an amide bond to form the QD–ZnAPPc-linked conjugate. The formation of the amide bond was confirmed using Raman and IR spectroscopies. Atomic force microscopy (AFM) and UV–Vis spectroscopy were used further to characterise the conjugate. Förster resonance energy transfer (FRET) resulted in stimulated emission of ZnAPPc in both the linked (QD–ZnAPPc-linked) and mixed (QD:ZnAPPc-mixed) conjugates. The linked L-cys and TGA QDs conjugates (QD–ZnAPPc-linked) gave the largest FRET efficiencies hence showing the advantages of covalent linking. Fluorescence quantum yields of QDs were decreased in QD:ZnAPPc-mixed and QD:ZnAPPc-linked.
- Full Text:
- Authors: D'Souza, Sarah , Antunes, Edith M , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247825 , vital:51621 , xlink:href="https://doi.org/10.1016/j.ica.2010.12.027"
- Description: The linkage of unsymmetrically monosubstituted 4-aminophenoxy zinc phthalocyanine (ZnAPPc, 5) to CdTe quantum dots capped with mercaptopropionic acid (MPA), L-cysteine (L-cys) or thioglycolic acid (TGA) has been achieved using the coupling agents ethyl-N(3-dimethylaminopropyl) carbodiimide and N-hydroxy succinimide, which facilitate formation of an amide bond to form the QD–ZnAPPc-linked conjugate. The formation of the amide bond was confirmed using Raman and IR spectroscopies. Atomic force microscopy (AFM) and UV–Vis spectroscopy were used further to characterise the conjugate. Förster resonance energy transfer (FRET) resulted in stimulated emission of ZnAPPc in both the linked (QD–ZnAPPc-linked) and mixed (QD:ZnAPPc-mixed) conjugates. The linked L-cys and TGA QDs conjugates (QD–ZnAPPc-linked) gave the largest FRET efficiencies hence showing the advantages of covalent linking. Fluorescence quantum yields of QDs were decreased in QD:ZnAPPc-mixed and QD:ZnAPPc-linked.
- Full Text:
Synthesis and photophysical studies of monocarboxy phthalocyanines containing quaternizable groups
- Arslanoğlu, Yasin, Nyokong, Tebello
- Authors: Arslanoğlu, Yasin , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/246992 , vital:51535 , xlink:href="https://doi.org/10.1016/j.poly.2011.08.009"
- Description: This work reports on the synthesis and photophysical properties of novel unsymmetrically substituted monocarboxy magnesium (MgPc, 3), aluminum (ClAlPc, 4) and unmetallated (H2Pc, 5) phthalocyanines. Magnesium phthalocyanine (3) was converted into water soluble quaternized derivative (QMgPc, 6) by reaction with methyl iodide. The synthesized phthalocyanines were characterized by IR, UV–Vis, NMR, mass spectrometry and elemental analyses. Photophysical and photochemical studies were carried out in order to determine the potential of the complexes as photosensitizers for use in photodynamic therapy. Triplet quantum yields ranged from 0.37 to 0.40 and triplet lifetimes from 110 to 140 μs in DMSO.
- Full Text:
- Authors: Arslanoğlu, Yasin , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/246992 , vital:51535 , xlink:href="https://doi.org/10.1016/j.poly.2011.08.009"
- Description: This work reports on the synthesis and photophysical properties of novel unsymmetrically substituted monocarboxy magnesium (MgPc, 3), aluminum (ClAlPc, 4) and unmetallated (H2Pc, 5) phthalocyanines. Magnesium phthalocyanine (3) was converted into water soluble quaternized derivative (QMgPc, 6) by reaction with methyl iodide. The synthesized phthalocyanines were characterized by IR, UV–Vis, NMR, mass spectrometry and elemental analyses. Photophysical and photochemical studies were carried out in order to determine the potential of the complexes as photosensitizers for use in photodynamic therapy. Triplet quantum yields ranged from 0.37 to 0.40 and triplet lifetimes from 110 to 140 μs in DMSO.
- Full Text:
Synthesis and photophysical studies of phthalocyanine–gold nanoparticle conjugates
- Nombona, Nolwazi, Antunes, Edith M, Litwinski, Christian, Nyokong, Tebello
- Authors: Nombona, Nolwazi , Antunes, Edith M , Litwinski, Christian , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/248438 , vital:51686 , xlink:href="https://doi.org/10.1039/C1DT11151E"
- Description: This work reports on the synthesis, characterization and photophysical studies of phthalocyanine–gold nanoparticle conjugates. The phthalocyanine complexes are: tris-(5-trifluoromethyl-2-mercaptopyridine)-2-(carboxy)phthalocyanine (3), 2,9,17,23-tetrakis-[(1, 6-hexanedithiol) phthalocyaninato]zinc(II) (8) and [8,15,22-tris-(naptho)-2(amidoethanethiol) phthalocyanato] zinc(II)(10). The gold nanoparticles were characterized using transmission electron microscopy, X-ray diffraction, atomic force microscopy and UV-vis spectroscopy where the size was confirmed to be ∼5 nm. The phthalocyanine Au nanoparticle conjugates showed lower fluorescence quantum yield values with similar fluorescence lifetimes compared to the free phthalocyanines. The Au nanoparticle conjugates of 3 and 10 also showed higher triplet quantum yields of 0.69 to 0.71, respectively. A lower triplet quantum yield was obtained for the conjugate compared to free phthalocyanine for complex 8. The triplet lifetimes ranged from 70 to 92 μs for the conjugates and from 110 to 304 μs for unbound Pc complexes.
- Full Text:
- Authors: Nombona, Nolwazi , Antunes, Edith M , Litwinski, Christian , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/248438 , vital:51686 , xlink:href="https://doi.org/10.1039/C1DT11151E"
- Description: This work reports on the synthesis, characterization and photophysical studies of phthalocyanine–gold nanoparticle conjugates. The phthalocyanine complexes are: tris-(5-trifluoromethyl-2-mercaptopyridine)-2-(carboxy)phthalocyanine (3), 2,9,17,23-tetrakis-[(1, 6-hexanedithiol) phthalocyaninato]zinc(II) (8) and [8,15,22-tris-(naptho)-2(amidoethanethiol) phthalocyanato] zinc(II)(10). The gold nanoparticles were characterized using transmission electron microscopy, X-ray diffraction, atomic force microscopy and UV-vis spectroscopy where the size was confirmed to be ∼5 nm. The phthalocyanine Au nanoparticle conjugates showed lower fluorescence quantum yield values with similar fluorescence lifetimes compared to the free phthalocyanines. The Au nanoparticle conjugates of 3 and 10 also showed higher triplet quantum yields of 0.69 to 0.71, respectively. A lower triplet quantum yield was obtained for the conjugate compared to free phthalocyanine for complex 8. The triplet lifetimes ranged from 70 to 92 μs for the conjugates and from 110 to 304 μs for unbound Pc complexes.
- Full Text:
Synthesis, characterization and application of monocarboxy-phthalocyanine-single walled carbon nanotube conjugates in electrocatalysis
- Mugadza, Tawanda, Nyokong, Tebello
- Authors: Mugadza, Tawanda , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247399 , vital:51577 , xlink:href="https://doi.org/10.1016/j.poly.2011.04.020"
- Description: In this paper we report on the synthesis, characterization and use of monocarboxy-phthalocyanine-single walled carbon nanotube conjugates in the electrocatalysis of amitrole and diuron. UV–Vis, FTIR and XRD spectroscopies were used in the characterization of cobalt(II)-tris(benzyl-mercapto)-mono(carboxyphenoxy)-phthalocyanine conjugates (CoMCPc–PA-SWCNT(linked)), while AFM was used to show changes in surface morphologies of the modified electrodes. Cyclic voltammetry and chronoamperometry were used for the electrocatalytic oxidation of amitrole and diuron on the modified glassy carbon electrode. The catalytic rate constants for amitrole and diuron were found to be 1.83 × 106 and 1.99 × 106 M−1 s−1, respectively. The linear range for both was 1.0 × 10−5–2.0 × 10−4 M, with sensitivities of 5.10 and 3.70 A mol−1 L cm−2 for amitrole and diuron, respectively. The limits of detection were estimated to be 0.14 and 0.20 μM for amitrole and diuron, respectively, using the 3δ notation.
- Full Text:
- Authors: Mugadza, Tawanda , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247399 , vital:51577 , xlink:href="https://doi.org/10.1016/j.poly.2011.04.020"
- Description: In this paper we report on the synthesis, characterization and use of monocarboxy-phthalocyanine-single walled carbon nanotube conjugates in the electrocatalysis of amitrole and diuron. UV–Vis, FTIR and XRD spectroscopies were used in the characterization of cobalt(II)-tris(benzyl-mercapto)-mono(carboxyphenoxy)-phthalocyanine conjugates (CoMCPc–PA-SWCNT(linked)), while AFM was used to show changes in surface morphologies of the modified electrodes. Cyclic voltammetry and chronoamperometry were used for the electrocatalytic oxidation of amitrole and diuron on the modified glassy carbon electrode. The catalytic rate constants for amitrole and diuron were found to be 1.83 × 106 and 1.99 × 106 M−1 s−1, respectively. The linear range for both was 1.0 × 10−5–2.0 × 10−4 M, with sensitivities of 5.10 and 3.70 A mol−1 L cm−2 for amitrole and diuron, respectively. The limits of detection were estimated to be 0.14 and 0.20 μM for amitrole and diuron, respectively, using the 3δ notation.
- Full Text:
Synthesis, characterization, and photophysical properties of novel ball-type dinuclear and mononuclear containing four 1, 1′-binaphthyl-8, 8′-diol bridged metallophthalocyanines with long triplet state lifetimes
- Canlıca, Mevlude, Nyokong, Tebello
- Authors: Canlıca, Mevlude , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/248406 , vital:51683 , xlink:href="https://doi.org/10.1039/C0DT01749C"
- Description: The syntheses of new ball-type dinuclear Si(IV)(CH3COO)2 and Ti(IV)O phthalocyanines and two different mononuclear Zn(II) and Ti(IV)O phthalocyanines containing four 1,1′-binaphthyl-8,8′-diol substituents on the peripheral positions are described. The structures of these compounds were characterized using the elemental analyzes, UV-Vis, FT-IR, 1H NMR and mass spectroscopies. The ΦF values are 0.14, 0.10, 0.04, 0.02, 0.07; ΦT values are 0.69, 0.71, 0.85, 0.33, 0.71 for 7–11, respectively. All complexes showed very long triplet lifetimes with τT 7510, 3190, 2880, 2370, 9470 μs for 7–11 in DMSO, respectively.
- Full Text:
- Authors: Canlıca, Mevlude , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/248406 , vital:51683 , xlink:href="https://doi.org/10.1039/C0DT01749C"
- Description: The syntheses of new ball-type dinuclear Si(IV)(CH3COO)2 and Ti(IV)O phthalocyanines and two different mononuclear Zn(II) and Ti(IV)O phthalocyanines containing four 1,1′-binaphthyl-8,8′-diol substituents on the peripheral positions are described. The structures of these compounds were characterized using the elemental analyzes, UV-Vis, FT-IR, 1H NMR and mass spectroscopies. The ΦF values are 0.14, 0.10, 0.04, 0.02, 0.07; ΦT values are 0.69, 0.71, 0.85, 0.33, 0.71 for 7–11, respectively. All complexes showed very long triplet lifetimes with τT 7510, 3190, 2880, 2370, 9470 μs for 7–11 in DMSO, respectively.
- Full Text:
Tartarus: A honeypot based malware tracking and mitigation framework
- Hunter, Samuel O, Irwin, Barry V W
- Authors: Hunter, Samuel O , Irwin, Barry V W
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428629 , vital:72525 , https://d1wqtxts1xzle7.cloudfront.net/96055420/Hunter-libre.pdf?1671479103=andresponse-content-disposi-tion=inline%3B+filename%3DTartarus_A_honeypot_based_malware_tracki.pdfandExpires=1714722666andSignature=JtPpR-IoAXILqsIJSlmCEvn6yyytE17YLQBeFJRKD5aBug-EbLxFpEGDf4GtQXHbxHvR4~E-b5QtMs1H6ruSYDti9fIHenRbLeepZTx9jYj92to3qZjy7UloigYbQuw0Y6sN95jI7d4HX-Xkspbz0~DsnzwFmLGopg7j9RZSHqpSpI~fBvlml3QQ2rLCm4aB9u8tSW8du5u~FiJgiLHNgJaPzEOzy4~yfKkXBh--LTFdgeAVYxQbOESGGh9k5bc-LDJhQ6dD5HpXsM3wKJvYuVyU6m83vT2scogVgKHIr-t~XuiqL35PfI3hs2c~ZO0TH4hCqwiNMHQ8GCYsLvllsA__andKey-Pair-Id=APKAJLOHF5GGSLRBV4ZA
- Description: On a daily basis many of the hosts connected to the Internet experi-ence continuous probing and attack from malicious entities. Detection and defence from these malicious entities has primarily been the con-cern of Intrusion Detection Systems, Intrusion Prevention Systems and Anti-Virus software. These systems rely heavily on known signatures to detect nefarious traffic. Due to the reliance on known malicious signa-tures, these systems have been at a serious disadvantage when it comes to detecting new, never before seen malware. This paper will introduce Tartarus which is a malware tracking and mitigation frame-work that makes use of honeypot technology in order to detect mali-cious traffic. Tartarus implements a dynamic quarantine technique to mitigate the spread of self propagating malware on a production net-work. In order to better understand the spread and impact of internet worms Tartarus is used to construct a detailed demographic of poten-tially malicious hosts on the internet. This host demographic is in turn used as a blacklist for firewall rule creation. The sources of malicious traffic is then illustrated through the use of a geolocation based visuali-sation.
- Full Text:
- Authors: Hunter, Samuel O , Irwin, Barry V W
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428629 , vital:72525 , https://d1wqtxts1xzle7.cloudfront.net/96055420/Hunter-libre.pdf?1671479103=andresponse-content-disposi-tion=inline%3B+filename%3DTartarus_A_honeypot_based_malware_tracki.pdfandExpires=1714722666andSignature=JtPpR-IoAXILqsIJSlmCEvn6yyytE17YLQBeFJRKD5aBug-EbLxFpEGDf4GtQXHbxHvR4~E-b5QtMs1H6ruSYDti9fIHenRbLeepZTx9jYj92to3qZjy7UloigYbQuw0Y6sN95jI7d4HX-Xkspbz0~DsnzwFmLGopg7j9RZSHqpSpI~fBvlml3QQ2rLCm4aB9u8tSW8du5u~FiJgiLHNgJaPzEOzy4~yfKkXBh--LTFdgeAVYxQbOESGGh9k5bc-LDJhQ6dD5HpXsM3wKJvYuVyU6m83vT2scogVgKHIr-t~XuiqL35PfI3hs2c~ZO0TH4hCqwiNMHQ8GCYsLvllsA__andKey-Pair-Id=APKAJLOHF5GGSLRBV4ZA
- Description: On a daily basis many of the hosts connected to the Internet experi-ence continuous probing and attack from malicious entities. Detection and defence from these malicious entities has primarily been the con-cern of Intrusion Detection Systems, Intrusion Prevention Systems and Anti-Virus software. These systems rely heavily on known signatures to detect nefarious traffic. Due to the reliance on known malicious signa-tures, these systems have been at a serious disadvantage when it comes to detecting new, never before seen malware. This paper will introduce Tartarus which is a malware tracking and mitigation frame-work that makes use of honeypot technology in order to detect mali-cious traffic. Tartarus implements a dynamic quarantine technique to mitigate the spread of self propagating malware on a production net-work. In order to better understand the spread and impact of internet worms Tartarus is used to construct a detailed demographic of poten-tially malicious hosts on the internet. This host demographic is in turn used as a blacklist for firewall rule creation. The sources of malicious traffic is then illustrated through the use of a geolocation based visuali-sation.
- Full Text:
Teacher professional development with an Education for Sustainable Development focus in South Africa: Development of a network, curriculum framework and resources for teacher education
- Authors: Lotz-Sisitka, Heila
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/128949 , vital:36193 , https://www.ajol.info/index.php/sajee/article/view/122242
- Description: This national case study reports on the development of a national network, curriculum framework and resources for teacher education, with specific focus on the inclusion of environment and sustainability, also known as education for sustainable development (ESD) in the South African teacher education system. It reviews and reports on the history of environment and sustainability education in teacher education, and from this, the national case study begins to conceptualise a new approach to environment and sustainability teacher education within a new curriculum policy environment, and a new teacher education and development policy environment.Action research case study methodology is used to document the first phase of the emergence of this network, and this report covers Phase 1 of the initiative, which covers formation of the network, review of previous practices, three conceptual development pilot studies undertaken in both in-service and pre-service teacher education environments and a piloting of a ‘Train the Trainers’ or ‘Educate the Teacher Educators’ programme, which complements and extends the actual teacher education and development (TED) programme under development.The study highlights critical insights of relevance to the shift to a content referenced curriculum in South Africa, and shows how the ‘knowledge mix’ which forms the foundation of the new Teacher Education Qualifications Framework can be engaged. It also highlights some features of the changing knowledge environment, and what dominant knowledge practices are in environment and sustainability-related teaching and teacher education practices, opening these up for further scrutiny. It raises concerns that dominant knowledge work, while integrating a range of forms of knowledge (as is expected of the teacher education system under the new policy), tends to be limited by content on problems and issues for raising awareness, and fails to develop deeper conceptual depth and understanding of environment and sustainability, as issues based knowledge dominates. Similarly, it fails to support social innovation as a response to environment and sustainability concerns, as awareness raising dominates in dominant knowledge work. The study provides a revised conceptual framework for the Teacher Development Network (TEDN) programme, with guidance on key elements necessary to take the programme forward in Phase 2.
- Full Text:
- Authors: Lotz-Sisitka, Heila
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/128949 , vital:36193 , https://www.ajol.info/index.php/sajee/article/view/122242
- Description: This national case study reports on the development of a national network, curriculum framework and resources for teacher education, with specific focus on the inclusion of environment and sustainability, also known as education for sustainable development (ESD) in the South African teacher education system. It reviews and reports on the history of environment and sustainability education in teacher education, and from this, the national case study begins to conceptualise a new approach to environment and sustainability teacher education within a new curriculum policy environment, and a new teacher education and development policy environment.Action research case study methodology is used to document the first phase of the emergence of this network, and this report covers Phase 1 of the initiative, which covers formation of the network, review of previous practices, three conceptual development pilot studies undertaken in both in-service and pre-service teacher education environments and a piloting of a ‘Train the Trainers’ or ‘Educate the Teacher Educators’ programme, which complements and extends the actual teacher education and development (TED) programme under development.The study highlights critical insights of relevance to the shift to a content referenced curriculum in South Africa, and shows how the ‘knowledge mix’ which forms the foundation of the new Teacher Education Qualifications Framework can be engaged. It also highlights some features of the changing knowledge environment, and what dominant knowledge practices are in environment and sustainability-related teaching and teacher education practices, opening these up for further scrutiny. It raises concerns that dominant knowledge work, while integrating a range of forms of knowledge (as is expected of the teacher education system under the new policy), tends to be limited by content on problems and issues for raising awareness, and fails to develop deeper conceptual depth and understanding of environment and sustainability, as issues based knowledge dominates. Similarly, it fails to support social innovation as a response to environment and sustainability concerns, as awareness raising dominates in dominant knowledge work. The study provides a revised conceptual framework for the Teacher Development Network (TEDN) programme, with guidance on key elements necessary to take the programme forward in Phase 2.
- Full Text:
Tebello Nyokong "As chemists, we are designers"
- Authors: Nolan, Cathy
- Date: 2011
- Language: English
- Type: Article , text
- Identifier: vital:7201 , http://hdl.handle.net/10962/d1006385
- Description: What is the common thread running through denim jeans, cancer and pesticides? None springs to mind, yet when chemist Tebello Nyokong describes her fascinating research, a link begins to emerge: light. A specialist in nanochemistry, Nyokong is using laser in ways that could revolutionize not only the diagnosis and treatment of cancer but also water purification.
- Full Text:
- Authors: Nolan, Cathy
- Date: 2011
- Language: English
- Type: Article , text
- Identifier: vital:7201 , http://hdl.handle.net/10962/d1006385
- Description: What is the common thread running through denim jeans, cancer and pesticides? None springs to mind, yet when chemist Tebello Nyokong describes her fascinating research, a link begins to emerge: light. A specialist in nanochemistry, Nyokong is using laser in ways that could revolutionize not only the diagnosis and treatment of cancer but also water purification.
- Full Text: