The impact of manufacturing variables on in vitro release of clobetasol 17-propionate from pilot scale cream formulations
- Fauzee, Ayesha F B, Khamanga, Sandile M, Walker, Roderick B
- Authors: Fauzee, Ayesha F B , Khamanga, Sandile M , Walker, Roderick B
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183872 , vital:44077 , xlink:href="https://doi.org/10.3109/03639045.2013.842579"
- Description: The purpose of the study was to evaluate the effect of different homogenization speeds and times, anchor speeds and cooling times on the viscosity and cumulative % clobetasol 17-propionate released per unit area at 72 h from pilot scale cream formulations. A 24 full factorial central composite design for four independent variables were investigated. Thirty pilot scale batches of cream formulations were manufactured using a Wintech® cream/ointment plant. The viscosity and in vitro release of CP were monitored and compared to an innovator product that is commercially available on the South African market, namely, Dermovate® cream. Contour and three-dimensional response surface plots were produced and the viscosity and cumulative % CP released per unit area at 72 h were found to be primarily dependent on the homogenization and anchor speeds. An increase in the homogenization and anchor speeds appeared to exhibit a synergistic effect on the resultant viscosity of the cream whereas an antagonistic effect was observed for the in vitro release of CP from the experimental cream formulations. The in vitro release profiles were best fitted to a Higuchi model and diffusion proved to be the dominant mechanism of drug release that was confirmed by use of the Korsmeyer–Peppas model. The research was further validated and confirmed by the high prognostic ability of response surface methodology (RSM) with a resultant mean percentage error of (±SD) 0.17 ± 0.093 suggesting that RSM may be an efficient tool for the development and optimization of topical formulations.
- Full Text:
- Date Issued: 2014
- Authors: Fauzee, Ayesha F B , Khamanga, Sandile M , Walker, Roderick B
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183872 , vital:44077 , xlink:href="https://doi.org/10.3109/03639045.2013.842579"
- Description: The purpose of the study was to evaluate the effect of different homogenization speeds and times, anchor speeds and cooling times on the viscosity and cumulative % clobetasol 17-propionate released per unit area at 72 h from pilot scale cream formulations. A 24 full factorial central composite design for four independent variables were investigated. Thirty pilot scale batches of cream formulations were manufactured using a Wintech® cream/ointment plant. The viscosity and in vitro release of CP were monitored and compared to an innovator product that is commercially available on the South African market, namely, Dermovate® cream. Contour and three-dimensional response surface plots were produced and the viscosity and cumulative % CP released per unit area at 72 h were found to be primarily dependent on the homogenization and anchor speeds. An increase in the homogenization and anchor speeds appeared to exhibit a synergistic effect on the resultant viscosity of the cream whereas an antagonistic effect was observed for the in vitro release of CP from the experimental cream formulations. The in vitro release profiles were best fitted to a Higuchi model and diffusion proved to be the dominant mechanism of drug release that was confirmed by use of the Korsmeyer–Peppas model. The research was further validated and confirmed by the high prognostic ability of response surface methodology (RSM) with a resultant mean percentage error of (±SD) 0.17 ± 0.093 suggesting that RSM may be an efficient tool for the development and optimization of topical formulations.
- Full Text:
- Date Issued: 2014
The influence of gold nanoparticles on the electroactivity of nickel tetrasulfonated phthalocyanine
- Maringa, Audacity, Nyokong, Tebello
- Authors: Maringa, Audacity , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189774 , vital:44930 , xlink:href="https://doi.org/10.1142/S1088424614500333"
- Description: We report on the electrodeposition of gold nanoparticles (AuNPs) on a glassy carbon electrode (GCE) followed by deposition of nickel tetrasulfonated phthalocyanine (NiTSPc) film by electropolymerization (poly-NiTSPc-GCE) to form Poly-NiTSPc/AuNPs-GCE. The presence of the gold nanoparticles caused a lowering of the anodic and cathodic peak separation (ΔEp) of ferricyanide from 126 mV on poly-NiTSPc to 110 mV on poly-NiTSPc/AuNPs. The electrooxidation of nitrite improved on modified electrodes compared to GCE, with the latter giving Ep = 0.78 V and the modified electrodes gave Ep = 0.62 V or 0.61 V. Poly-NiTSPc/AuNPs-GCE had higher currents compared to poly-NiTSPc-GCE. This indicates the enhancement effect caused by the AuNPs. Electrochemical impedance spectroscopy and chronoamperometric studies also showed that poly-NiTSPc/AuNPs-GCE was a better electrocatalyst than poly-NiTSPc-GCE or AuNPs-GCE.
- Full Text:
- Date Issued: 2014
- Authors: Maringa, Audacity , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189774 , vital:44930 , xlink:href="https://doi.org/10.1142/S1088424614500333"
- Description: We report on the electrodeposition of gold nanoparticles (AuNPs) on a glassy carbon electrode (GCE) followed by deposition of nickel tetrasulfonated phthalocyanine (NiTSPc) film by electropolymerization (poly-NiTSPc-GCE) to form Poly-NiTSPc/AuNPs-GCE. The presence of the gold nanoparticles caused a lowering of the anodic and cathodic peak separation (ΔEp) of ferricyanide from 126 mV on poly-NiTSPc to 110 mV on poly-NiTSPc/AuNPs. The electrooxidation of nitrite improved on modified electrodes compared to GCE, with the latter giving Ep = 0.78 V and the modified electrodes gave Ep = 0.62 V or 0.61 V. Poly-NiTSPc/AuNPs-GCE had higher currents compared to poly-NiTSPc-GCE. This indicates the enhancement effect caused by the AuNPs. Electrochemical impedance spectroscopy and chronoamperometric studies also showed that poly-NiTSPc/AuNPs-GCE was a better electrocatalyst than poly-NiTSPc-GCE or AuNPs-GCE.
- Full Text:
- Date Issued: 2014
The life history traits of the arctiine moth Pareuchaetes insulata, a biological control agent of Chromolaena odorata in South Africa
- Uyi, Osariyekemwen O, Zachariades, Costas, Hill, Martin P
- Authors: Uyi, Osariyekemwen O , Zachariades, Costas , Hill, Martin P
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/406170 , vital:70244 , xlink:href="https://hdl.handle.net/10520/EJC160238"
- Description: Pareuchaetes insulata (Walker) (Lepidoptera: Erebidae: Arctiinae) was released in KwaZulu-Natal, South Africa, as a biological control agent against Chromolaena odorata (L.) King and Robinson (Asteraceae) between 2001 and 2009. Although the moth did establish at one out of some 30 release sites, its population level is generally low in the field. Two closely related biological control agents, P. pseudoinsulata Rego Barros and P. aurata aurata (Butler) had previously failed to establish despite several years of releases. Studies of life history traits of P. insulata (males and females) were conducted to determine whether several aspects of its developmental and reproductive biology can explain its poor performance, and to compare the development and reproductive biology of P. insulata with the two other closely related species. At 25 °C, overall mortality of immature stages was generally low (below 12 %). Although the duration of the larval life stage was statistically longer for females, overall they eclosed as adults before the males (i.e. protogyny). Pupal mass, growth rate and total leaf area consumed were higher in females. Mated females laid 74% of their eggs on the first four nights following eclosion and lived an average of 5.92 ± 0.19 days. The moth also showed good biological attributes such as high fecundity (number of eggs), egg hatchability and female mating success (the number of matings that resulted in fertile eggs). Significant positive correlations were detected between insect performance metrics and leaf consumption and between fecundity and pupal mass. A 23 % greater lifetime reproductive output (387.62 ± 19.50 eggs per female) for P. insulata compared with P. aurata aurata was recorded. We hypothesize that the absence of protandry in P. insulata might have contributed to the low population levels of the moth in the field. The results of this study contribute to our understanding of the life history traits of erebid moths in the subfamily Arctiinae deployed for the biological control of C. odorata.
- Full Text:
- Date Issued: 2014
- Authors: Uyi, Osariyekemwen O , Zachariades, Costas , Hill, Martin P
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/406170 , vital:70244 , xlink:href="https://hdl.handle.net/10520/EJC160238"
- Description: Pareuchaetes insulata (Walker) (Lepidoptera: Erebidae: Arctiinae) was released in KwaZulu-Natal, South Africa, as a biological control agent against Chromolaena odorata (L.) King and Robinson (Asteraceae) between 2001 and 2009. Although the moth did establish at one out of some 30 release sites, its population level is generally low in the field. Two closely related biological control agents, P. pseudoinsulata Rego Barros and P. aurata aurata (Butler) had previously failed to establish despite several years of releases. Studies of life history traits of P. insulata (males and females) were conducted to determine whether several aspects of its developmental and reproductive biology can explain its poor performance, and to compare the development and reproductive biology of P. insulata with the two other closely related species. At 25 °C, overall mortality of immature stages was generally low (below 12 %). Although the duration of the larval life stage was statistically longer for females, overall they eclosed as adults before the males (i.e. protogyny). Pupal mass, growth rate and total leaf area consumed were higher in females. Mated females laid 74% of their eggs on the first four nights following eclosion and lived an average of 5.92 ± 0.19 days. The moth also showed good biological attributes such as high fecundity (number of eggs), egg hatchability and female mating success (the number of matings that resulted in fertile eggs). Significant positive correlations were detected between insect performance metrics and leaf consumption and between fecundity and pupal mass. A 23 % greater lifetime reproductive output (387.62 ± 19.50 eggs per female) for P. insulata compared with P. aurata aurata was recorded. We hypothesize that the absence of protandry in P. insulata might have contributed to the low population levels of the moth in the field. The results of this study contribute to our understanding of the life history traits of erebid moths in the subfamily Arctiinae deployed for the biological control of C. odorata.
- Full Text:
- Date Issued: 2014
the programmable bride
- Authors: Krueger, Anton
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/229698 , vital:49701 , xlink:href="https://hdl.handle.net/10520/EJC156969"
- Description: the man gently opens his machine and finding an agreeable port for his firm flash, he eagerly installs the software he's been waiting on for so very long... once booted up, the man takes his first tentative steps, finding his bride perfect in every way, already completely in love with him, and dreamy... the man tenderly reaches out for her-she understands him so well, she's concerned about his needs, she wants to know how he feels, wants only to please him, she only-/but-there's an interruption/somebody's on the stairs, someone's knocking at his door-the man is forced to close her down a little too abruptly, shutting the machine to attend to other matters while he's away he can't wait to get back, he thinks about her all the time; he longs to flip his laptop lid up, to open her again... but when finally he silently prises open the instrument of his heart's desires, she seems a little disorientated... he didn't shut her down properly …
- Full Text:
- Date Issued: 2014
- Authors: Krueger, Anton
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/229698 , vital:49701 , xlink:href="https://hdl.handle.net/10520/EJC156969"
- Description: the man gently opens his machine and finding an agreeable port for his firm flash, he eagerly installs the software he's been waiting on for so very long... once booted up, the man takes his first tentative steps, finding his bride perfect in every way, already completely in love with him, and dreamy... the man tenderly reaches out for her-she understands him so well, she's concerned about his needs, she wants to know how he feels, wants only to please him, she only-/but-there's an interruption/somebody's on the stairs, someone's knocking at his door-the man is forced to close her down a little too abruptly, shutting the machine to attend to other matters while he's away he can't wait to get back, he thinks about her all the time; he longs to flip his laptop lid up, to open her again... but when finally he silently prises open the instrument of his heart's desires, she seems a little disorientated... he didn't shut her down properly …
- Full Text:
- Date Issued: 2014
The relationship between double taxation agreements and the provisions of the South African Income Tax Act
- Authors: Stack, Elizabeth M
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: Article
- Identifier: vital:21102 , http://hdl.handle.net/10962/6384 , http://journals.co.za/content/jefs/7/2/EJC157823
- Description: This article investigates the legal status of Double Taxation Agreements, and the relationship between Double Taxation Agreements, which are concluded in terms of section 108 of the Income Tax Act, and the provisions of the Income Tax Act (taking into account the provisions of the Constitution, and the national and international rules for the interpretation of statutes). An important conclusion reached was that as the Vienna Convention on the Law of Treaties represents customary international law and as such forms part of South African law, the principles contained in the treaty should be taken into account when interpreting South African legislation (including Double Taxation Agreements).The final conclusion of the research was that Double Taxation Agreements have a dual nature – forming part of domestic legislation and being classified as international agreements. The provisions of the Double Taxation Agreement should be taken as overriding any conflicting legislation in the Income Tax Act.
- Full Text:
- Date Issued: 2014
- Authors: Stack, Elizabeth M
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: Article
- Identifier: vital:21102 , http://hdl.handle.net/10962/6384 , http://journals.co.za/content/jefs/7/2/EJC157823
- Description: This article investigates the legal status of Double Taxation Agreements, and the relationship between Double Taxation Agreements, which are concluded in terms of section 108 of the Income Tax Act, and the provisions of the Income Tax Act (taking into account the provisions of the Constitution, and the national and international rules for the interpretation of statutes). An important conclusion reached was that as the Vienna Convention on the Law of Treaties represents customary international law and as such forms part of South African law, the principles contained in the treaty should be taken into account when interpreting South African legislation (including Double Taxation Agreements).The final conclusion of the research was that Double Taxation Agreements have a dual nature – forming part of domestic legislation and being classified as international agreements. The provisions of the Double Taxation Agreement should be taken as overriding any conflicting legislation in the Income Tax Act.
- Full Text:
- Date Issued: 2014
The role of knowledge in a democratic society: investigations into mediation and change-oriented learning in water management practices
- Burt, Jane C, Lotz-Sisitka, Heila, Rivers, Nina, Berold, Robert, Ntshudu, Monde, Wigley, Tim, Stanford, Mindy, Jenkin, Treve, Buzani, Mangalisa, Kruger, Ewald
- Authors: Burt, Jane C , Lotz-Sisitka, Heila , Rivers, Nina , Berold, Robert , Ntshudu, Monde , Wigley, Tim , Stanford, Mindy , Jenkin, Treve , Buzani, Mangalisa , Kruger, Ewald
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/436770 , vital:73300 , ISBN 978-1-4312-0519-6 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/2074-1-13.pdf
- Description: This project emerged from two previous Water Research Commission (WRC) research projects. In 2006 Heila Lotz-Sisitka and Jane Burt (Lotz-Sisitka, 2006) undertook research on participation in the establishment of integrated water resources management (IWRM) structures. They found that while much emphasis had gone into the establishment of water re-sources management structures, very little attention was being given to building people’s capacity to participate effectively in these structures. Access to and the ability to make use of knowledge resources about wa-ter resources management is a key aspect of such capacity building.
- Full Text:
- Date Issued: 2014
- Authors: Burt, Jane C , Lotz-Sisitka, Heila , Rivers, Nina , Berold, Robert , Ntshudu, Monde , Wigley, Tim , Stanford, Mindy , Jenkin, Treve , Buzani, Mangalisa , Kruger, Ewald
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/436770 , vital:73300 , ISBN 978-1-4312-0519-6 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/2074-1-13.pdf
- Description: This project emerged from two previous Water Research Commission (WRC) research projects. In 2006 Heila Lotz-Sisitka and Jane Burt (Lotz-Sisitka, 2006) undertook research on participation in the establishment of integrated water resources management (IWRM) structures. They found that while much emphasis had gone into the establishment of water re-sources management structures, very little attention was being given to building people’s capacity to participate effectively in these structures. Access to and the ability to make use of knowledge resources about wa-ter resources management is a key aspect of such capacity building.
- Full Text:
- Date Issued: 2014
The territorial invasion of Apis florea in Africa
- Bezabih, G, Adgaba, N, Hepburn, H Randall, Pirk, Christian W W
- Authors: Bezabih, G , Adgaba, N , Hepburn, H Randall , Pirk, Christian W W
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/452044 , vital:75098 , https://hdl.handle.net/10520/EJC163586
- Description: Apis florea took an inadvertent leap onto the African continent and was detected in Khartoum, Sudan, for the first time in 1985 (Lord and Nagi 1987; Mogga and Ruttner 1988). The occurrence of these bees in Africa is very likely via global transportation. Since then, A. florea has been gradually expanding its territory to the whole of Sudan (Moritz et al. 2010) and to neighbouring countries. Moreover, in Asia A. florea has been steadily expanding westwards, and it is now well established in the Middle East (Hepburn et al. 2005; Haddad et al. 2009).
- Full Text:
- Date Issued: 2014
- Authors: Bezabih, G , Adgaba, N , Hepburn, H Randall , Pirk, Christian W W
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/452044 , vital:75098 , https://hdl.handle.net/10520/EJC163586
- Description: Apis florea took an inadvertent leap onto the African continent and was detected in Khartoum, Sudan, for the first time in 1985 (Lord and Nagi 1987; Mogga and Ruttner 1988). The occurrence of these bees in Africa is very likely via global transportation. Since then, A. florea has been gradually expanding its territory to the whole of Sudan (Moritz et al. 2010) and to neighbouring countries. Moreover, in Asia A. florea has been steadily expanding westwards, and it is now well established in the Middle East (Hepburn et al. 2005; Haddad et al. 2009).
- Full Text:
- Date Issued: 2014
Towards a platform to visualize the state of South Africa's information security
- Swart, Ignus, Irwin, Barry V W, Grobler, Marthie
- Authors: Swart, Ignus , Irwin, Barry V W , Grobler, Marthie
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429688 , vital:72632 , 10.1109/ISSA.2014.6950511
- Description: Attacks via the Internet infrastructure is increasingly becoming a daily occurrence and South Africa is no exception. In response, certain governments have published strategies pertaining to information security on a national level. These policies aim to ensure that critical infrastructure is protected, and that there is a move towards a greater state of information security readiness. This is also the case for South Africa where a variety of policy initiatives have started to gain momentum. While establishing strategy and policy is essential, ensuring its implementation is often difficult and dependent on the availability of resources. This is even more so in the case of information security since virtually all standardized security improvement processes start off with specifying that a proper inventory is required of all hardware, software, people and processes. While this may be possible to achieve at an organizational level, it is far more challenging on a national level. In this paper, the authors examine the possibility of making use of available data sources to achieve inventory of infrastructure on a national level and to visualize the state of a country's information security in at least a partial manner.
- Full Text:
- Date Issued: 2014
- Authors: Swart, Ignus , Irwin, Barry V W , Grobler, Marthie
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429688 , vital:72632 , 10.1109/ISSA.2014.6950511
- Description: Attacks via the Internet infrastructure is increasingly becoming a daily occurrence and South Africa is no exception. In response, certain governments have published strategies pertaining to information security on a national level. These policies aim to ensure that critical infrastructure is protected, and that there is a move towards a greater state of information security readiness. This is also the case for South Africa where a variety of policy initiatives have started to gain momentum. While establishing strategy and policy is essential, ensuring its implementation is often difficult and dependent on the availability of resources. This is even more so in the case of information security since virtually all standardized security improvement processes start off with specifying that a proper inventory is required of all hardware, software, people and processes. While this may be possible to achieve at an organizational level, it is far more challenging on a national level. In this paper, the authors examine the possibility of making use of available data sources to achieve inventory of infrastructure on a national level and to visualize the state of a country's information security in at least a partial manner.
- Full Text:
- Date Issued: 2014
Towards a Sandbox for the Deobfuscation and Dissection of PHP Malware
- Wrench, Peter M, Irwin, Barry V W
- Authors: Wrench, Peter M , Irwin, Barry V W
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429700 , vital:72633 , 10.1109/ISSA.2014.6950504
- Description: The creation and proliferation of PHP-based Remote Access Trojans (or web shells) used in both the compromise and post exploitation of web platforms has fuelled research into automated methods of dissecting and analysing these shells. Current malware tools disguise themselves by making use of obfuscation techniques designed to frustrate any efforts to dissect or reverse engineer the code. Advanced code engineering can even cause malware to behave differently if it detects that it is not running on the system for which it was originally targeted. To combat these defensive techniques, this paper presents a sandbox-based environment that aims to accurately mimic a vulnerable host and is capable of semi-automatic semantic dissection and syntactic deobfuscation of PHP code.
- Full Text:
- Date Issued: 2014
- Authors: Wrench, Peter M , Irwin, Barry V W
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429700 , vital:72633 , 10.1109/ISSA.2014.6950504
- Description: The creation and proliferation of PHP-based Remote Access Trojans (or web shells) used in both the compromise and post exploitation of web platforms has fuelled research into automated methods of dissecting and analysing these shells. Current malware tools disguise themselves by making use of obfuscation techniques designed to frustrate any efforts to dissect or reverse engineer the code. Advanced code engineering can even cause malware to behave differently if it detects that it is not running on the system for which it was originally targeted. To combat these defensive techniques, this paper presents a sandbox-based environment that aims to accurately mimic a vulnerable host and is capable of semi-automatic semantic dissection and syntactic deobfuscation of PHP code.
- Full Text:
- Date Issued: 2014
Towards building an indigenous knowledge platform to enable culturally-sensitive education underpinned by technological pedagogical and content knowledge (TPACK)
- Ntšekhe, Mathe, Terzoli, Alfredo, Thinyane, Mamello
- Authors: Ntšekhe, Mathe , Terzoli, Alfredo , Thinyane, Mamello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431424 , vital:72773 , http://proceedings.e-skillsconference.org/2014/e-skills275-284Ntsekhe821.pdf
- Description: The everyday use of Information and Communication Technologies (ICTs) is ingrained to the fabric of today’s society. A question open for debate is whether this use is or can be optimized to engender authentic solutions, which are aligned to the natural environment of the people? In this paper, we examine at the question from the vantage point of ed-ucating the rural African child. We engage with the sub-question: can ICTs facilitate education grounded in people's own realities, especially those of the marginalized rural poor? We believe this is possible under specific conditions, which include making Indigenous Knowledge (IK) readily available. We propose building an ICT platform that allows injec-tion of IK into the education process: develop a solution that valorizes IK, but also supports efforts to use ICTs in education driven by Tech-nology, Pedagogy, and Content Knowledge (TPACK) framework. The main goal of this framework is to facilitate effective teaching with tech-nology. TPACK partially embeds IK within pedagogical knowledge and ‘contexts’ of learning; we argue for explicit inclusion of IK within the framework to complement the other knowledges.
- Full Text:
- Date Issued: 2014
- Authors: Ntšekhe, Mathe , Terzoli, Alfredo , Thinyane, Mamello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431424 , vital:72773 , http://proceedings.e-skillsconference.org/2014/e-skills275-284Ntsekhe821.pdf
- Description: The everyday use of Information and Communication Technologies (ICTs) is ingrained to the fabric of today’s society. A question open for debate is whether this use is or can be optimized to engender authentic solutions, which are aligned to the natural environment of the people? In this paper, we examine at the question from the vantage point of ed-ucating the rural African child. We engage with the sub-question: can ICTs facilitate education grounded in people's own realities, especially those of the marginalized rural poor? We believe this is possible under specific conditions, which include making Indigenous Knowledge (IK) readily available. We propose building an ICT platform that allows injec-tion of IK into the education process: develop a solution that valorizes IK, but also supports efforts to use ICTs in education driven by Tech-nology, Pedagogy, and Content Knowledge (TPACK) framework. The main goal of this framework is to facilitate effective teaching with tech-nology. TPACK partially embeds IK within pedagogical knowledge and ‘contexts’ of learning; we argue for explicit inclusion of IK within the framework to complement the other knowledges.
- Full Text:
- Date Issued: 2014
Towards developing a social science research agenda for the South African water sector
- Munnik, Victor, Burt, Jane C
- Authors: Munnik, Victor , Burt, Jane C
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/436797 , vital:73306 , ISBN 978-1-4312-0511-0 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/KV%20325-13.pdf
- Description: The report explores what is meant by social research and introduces a synthetic, interdisciplinary framework for water research that side steps the ‘hard’ and ‘soft’ science debate by demonstrating how different disci-plines help us understand different layers of reality when dealing with complex challenges.
- Full Text:
- Date Issued: 2014
- Authors: Munnik, Victor , Burt, Jane C
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/436797 , vital:73306 , ISBN 978-1-4312-0511-0 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/KV%20325-13.pdf
- Description: The report explores what is meant by social research and introduces a synthetic, interdisciplinary framework for water research that side steps the ‘hard’ and ‘soft’ science debate by demonstrating how different disci-plines help us understand different layers of reality when dealing with complex challenges.
- Full Text:
- Date Issued: 2014
Transformative learning and individual adaptation
- Kronlid, David O, Lotz-Sisitka, Heila
- Authors: Kronlid, David O , Lotz-Sisitka, Heila
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/437147 , vital:73347 , ISBN 978-1-137-42804-2 , https://doi.org/10.1057/9781137428042_4
- Description: The first part of this chapter explores learning as a Capability to transformatively engage with the world in a climate change context. It draws on previous work that shows that modern as well as indigenous knowledge systems are being affected by climate change. There is no doubt that for societies to adapt to climate change, there is a need for substantive transformative learning, as people everywhere will need to learn new values, practices, relations, and new ways of being and becoming. Such learning on a societal scale has occurred before—as humans adapted to the emergence of the Industrial Revolu-tion, for example. However, the transformation in the climate change adaptation context in many ways is in response to maladaptations that emerged from previous massive societal transformation processes, making this complex to navigate. It is also well known that climate change is leaving many people insecure and highly vulnerable to climate change impacts; it is affecting us all, but the impacts are uneven (Field et al. 2014), requiring different kinds of transformative learning processes in different places and contexts. In this chapter, we therefore propose that, under climate change conditions, we view learning as a key Capability in climate adaptation contexts.
- Full Text:
- Date Issued: 2014
- Authors: Kronlid, David O , Lotz-Sisitka, Heila
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/437147 , vital:73347 , ISBN 978-1-137-42804-2 , https://doi.org/10.1057/9781137428042_4
- Description: The first part of this chapter explores learning as a Capability to transformatively engage with the world in a climate change context. It draws on previous work that shows that modern as well as indigenous knowledge systems are being affected by climate change. There is no doubt that for societies to adapt to climate change, there is a need for substantive transformative learning, as people everywhere will need to learn new values, practices, relations, and new ways of being and becoming. Such learning on a societal scale has occurred before—as humans adapted to the emergence of the Industrial Revolu-tion, for example. However, the transformation in the climate change adaptation context in many ways is in response to maladaptations that emerged from previous massive societal transformation processes, making this complex to navigate. It is also well known that climate change is leaving many people insecure and highly vulnerable to climate change impacts; it is affecting us all, but the impacts are uneven (Field et al. 2014), requiring different kinds of transformative learning processes in different places and contexts. In this chapter, we therefore propose that, under climate change conditions, we view learning as a key Capability in climate adaptation contexts.
- Full Text:
- Date Issued: 2014
Trends in the TD-DFT calculations of porphyrin and phthalocyanine analogs
- Mack, John, Stone, Justin, Nyokong, Tebello
- Authors: Mack, John , Stone, Justin , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193882 , vital:45402 , xlink:href="https://doi.org/10.1142/S108842461450045X"
- Description: In 2005, Kobayashi and coworkers reported trends in the TD-DFT spectra of 17 Zn (II) porphyrinoids [J. Am. Chem. Soc. 2005; 127: 17697] that were analyzed using Michl's perimeter model as part of a study of the anomalous magnetic circular dichroism (MCD) spectroscopy of zinc tetraphenyltetraacenaphthoporphyrin. In recent years, it has become increasingly clear that TD-DFT calculations with the commonly used hybrid B3LYP exchange-correlation functional of the Gaussian software package are problematic in the B-band region of porphyrinoid spectra, since the degree of configurational interaction between the B and higher energy ππ* state appears to be significantly overestimated. The CAM-B3LYP functional is now often preferred for analyzing the optical properties of porphyrinoids, since it includes a long-range correction of the exchange potential, which incorporates an increasing fraction of Hartree–Fock (HF) exchange as the interelectronic separation increases, making it better suited for studying compounds where there is significant charge transfer in the electronic excited states. The trends in the TD-DFT calculations are reexamined with a wider range porphyrinoid compounds including several with pyrazino moieties and are found to provide a closer agreement with the experimental in the B-band region for complexes such as zinc tetraphenylporphyrin and phthalocyanine.
- Full Text:
- Date Issued: 2014
- Authors: Mack, John , Stone, Justin , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193882 , vital:45402 , xlink:href="https://doi.org/10.1142/S108842461450045X"
- Description: In 2005, Kobayashi and coworkers reported trends in the TD-DFT spectra of 17 Zn (II) porphyrinoids [J. Am. Chem. Soc. 2005; 127: 17697] that were analyzed using Michl's perimeter model as part of a study of the anomalous magnetic circular dichroism (MCD) spectroscopy of zinc tetraphenyltetraacenaphthoporphyrin. In recent years, it has become increasingly clear that TD-DFT calculations with the commonly used hybrid B3LYP exchange-correlation functional of the Gaussian software package are problematic in the B-band region of porphyrinoid spectra, since the degree of configurational interaction between the B and higher energy ππ* state appears to be significantly overestimated. The CAM-B3LYP functional is now often preferred for analyzing the optical properties of porphyrinoids, since it includes a long-range correction of the exchange potential, which incorporates an increasing fraction of Hartree–Fock (HF) exchange as the interelectronic separation increases, making it better suited for studying compounds where there is significant charge transfer in the electronic excited states. The trends in the TD-DFT calculations are reexamined with a wider range porphyrinoid compounds including several with pyrazino moieties and are found to provide a closer agreement with the experimental in the B-band region for complexes such as zinc tetraphenylporphyrin and phthalocyanine.
- Full Text:
- Date Issued: 2014
Understanding food security in a perfect storm: an ecosystem services approach
- Poppy, G M, Chiotha, S, Eigenbrod, Felix, Harvey, Celia A, Honza´k, M, Hudson, Malcolm D, Jarvis, A, Madise, Nyovani J, Schreckenberg, Kate, Shackleton, Charlie M, Villa, Ferdinando, Dawson, Terrence P
- Authors: Poppy, G M , Chiotha, S , Eigenbrod, Felix , Harvey, Celia A , Honza´k, M , Hudson, Malcolm D , Jarvis, A , Madise, Nyovani J , Schreckenberg, Kate , Shackleton, Charlie M , Villa, Ferdinando , Dawson, Terrence P
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/398423 , vital:69410 , xlink:href="https://doi.org/10.1098/rstb.2012.0288"
- Description: Achieving food security in a ‘perfect storm’ scenario is a grand challenge for society. Climate change and an expanding global population act in concert to make global food security even more complex and demanding. As achieving food security and the millennium development goal (MDG) to eradicate hunger influences the attainment of other MDGs, it is imperative that we offer solutions which are complementary and do not oppose one another. Sustainable intensification of agriculture has been proposed as a way to address hunger while also minimizing further environmental impact. However, the desire to raise productivity and yields has historically led to a degraded environment, reduced biodiversity and a reduction in ecosystem services (ES), with the greatest impacts affecting the poor. This paper proposes that the ES framework coupled with a policy response framework, for example Driver-Pressure-State-Impact-Response (DPSIR), can allow food security to be delivered alongside healthy ecosystems, which provide many other valuable services to humankind. Too often, agro-ecosystems have been considered as separate from other natural ecosystems and insufficient attention has been paid to the way in which services can flow to and from the agro-ecosystem to surrounding ecosystems. Highlighting recent research in a large multi-disciplinary project (ASSETS), we illustrate the ES approach to food security using a case study from the Zomba district of Malawi.
- Full Text:
- Date Issued: 2014
- Authors: Poppy, G M , Chiotha, S , Eigenbrod, Felix , Harvey, Celia A , Honza´k, M , Hudson, Malcolm D , Jarvis, A , Madise, Nyovani J , Schreckenberg, Kate , Shackleton, Charlie M , Villa, Ferdinando , Dawson, Terrence P
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/398423 , vital:69410 , xlink:href="https://doi.org/10.1098/rstb.2012.0288"
- Description: Achieving food security in a ‘perfect storm’ scenario is a grand challenge for society. Climate change and an expanding global population act in concert to make global food security even more complex and demanding. As achieving food security and the millennium development goal (MDG) to eradicate hunger influences the attainment of other MDGs, it is imperative that we offer solutions which are complementary and do not oppose one another. Sustainable intensification of agriculture has been proposed as a way to address hunger while also minimizing further environmental impact. However, the desire to raise productivity and yields has historically led to a degraded environment, reduced biodiversity and a reduction in ecosystem services (ES), with the greatest impacts affecting the poor. This paper proposes that the ES framework coupled with a policy response framework, for example Driver-Pressure-State-Impact-Response (DPSIR), can allow food security to be delivered alongside healthy ecosystems, which provide many other valuable services to humankind. Too often, agro-ecosystems have been considered as separate from other natural ecosystems and insufficient attention has been paid to the way in which services can flow to and from the agro-ecosystem to surrounding ecosystems. Highlighting recent research in a large multi-disciplinary project (ASSETS), we illustrate the ES approach to food security using a case study from the Zomba district of Malawi.
- Full Text:
- Date Issued: 2014
Unsymmetrically substituted nickel triazatetra-benzcorrole and phthalocynanine complexes
- Adegoke, Oluwasesan, Nyokong, Tebello
- Authors: Adegoke, Oluwasesan , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189818 , vital:44934 , xlink:href="https://doi.org/10.1007/s10895-013-1317-4"
- Description: We report on the design and application of fluorescent nanoprobes based on the covalent linking of L-glutathione-capped CdSe@ZnS quantum dots (QDs) to newly synthesized unsymmetrically substituted nickel mercaptosuccinic acid triazatetra-benzcorrole (3) and phthalocyanine (4) complexes. Fluorescence quenching of the QDs occurred on conjugation to complexes 3 or 4. The nanoprobes were selectively screened in the presence of different cations and Hg2+ showed excellent affinity in “turning ON” the fluorescence of the nanoprobes. Experimental results showed that the sensitivity of QDs-4 towards Hg2+ was much higher than that of QDs-3 nanoprobe. The mechanism of reaction has been elucidated based on the ability of Hg2+ to coordinate with the sulphur atom of the Ni complex ring and apparently “turn ON” the fluorescence of the linked QDs.
- Full Text:
- Date Issued: 2014
- Authors: Adegoke, Oluwasesan , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189818 , vital:44934 , xlink:href="https://doi.org/10.1007/s10895-013-1317-4"
- Description: We report on the design and application of fluorescent nanoprobes based on the covalent linking of L-glutathione-capped CdSe@ZnS quantum dots (QDs) to newly synthesized unsymmetrically substituted nickel mercaptosuccinic acid triazatetra-benzcorrole (3) and phthalocyanine (4) complexes. Fluorescence quenching of the QDs occurred on conjugation to complexes 3 or 4. The nanoprobes were selectively screened in the presence of different cations and Hg2+ showed excellent affinity in “turning ON” the fluorescence of the nanoprobes. Experimental results showed that the sensitivity of QDs-4 towards Hg2+ was much higher than that of QDs-3 nanoprobe. The mechanism of reaction has been elucidated based on the ability of Hg2+ to coordinate with the sulphur atom of the Ni complex ring and apparently “turn ON” the fluorescence of the linked QDs.
- Full Text:
- Date Issued: 2014
Variations in moult, morphology, movement and survival rates of the Sombre Greenbul Andropadus importunus within southern Africa
- Authors: Bonnevie, Bo T
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/448368 , vital:74725 , https://doi.org/10.2989/00306525.2014.902403
- Description: Ringing data from the South African bird ringing unit, SAFRING, were analysed to explore variations and trends in population parameters of the Sombre Greenbul Andropadus importunus in southern Africa. Adult and juvenile body mass increased southwards, whereas the relative sizes of wings and bills decreased southwards. Recapture and recovery data indicated that adults have very high site fidelity and suggested that juvenile dispersal is limited. The annual survival rate of adults was on average more than twice that of juveniles and there was little regional variation within either age group. The onset of primary wing moult became progressively later northwards, but the duration of moult did not vary significantly with latitude. Juveniles started their first normally descendent wing moult sequence about one month after adults.
- Full Text:
- Date Issued: 2014
- Authors: Bonnevie, Bo T
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/448368 , vital:74725 , https://doi.org/10.2989/00306525.2014.902403
- Description: Ringing data from the South African bird ringing unit, SAFRING, were analysed to explore variations and trends in population parameters of the Sombre Greenbul Andropadus importunus in southern Africa. Adult and juvenile body mass increased southwards, whereas the relative sizes of wings and bills decreased southwards. Recapture and recovery data indicated that adults have very high site fidelity and suggested that juvenile dispersal is limited. The annual survival rate of adults was on average more than twice that of juveniles and there was little regional variation within either age group. The onset of primary wing moult became progressively later northwards, but the duration of moult did not vary significantly with latitude. Juveniles started their first normally descendent wing moult sequence about one month after adults.
- Full Text:
- Date Issued: 2014
Voltammetric investigation of complex growth media at a bare glassy carbon electrode: a case study of oxytetracycline
- Kruid, Jan, Fogel Ronen, Limson, Janice
- Authors: Kruid, Jan , Fogel Ronen , Limson, Janice
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431206 , vital:72753 , xlink:href="https://doi.org/10.1016/j.electacta.2013.08.188"
- Description: Reports regarding the voltammetric properties of microbiological growth media are scarce in the literature and limited focus has been placed towards the application of electroanalysis for analyte monitoring in these complex media. This work aims to investigate the viability of voltammetry as a quantification method for analytes in microbiological growth media, using oxytetracycline (OTC) as a model analyte. Analysis of both commercially available and laboratory prepared growth media indicated the presence of interfering media components which produced anodic peaks at potentials ranging from ∼+0.85 V to ∼+1.30 V (vs. Ag/AgCl) under acidic conditions and ∼+0.62 V to ∼+1.35 V (vs. Ag/AgCl) under neutral pH. These peaks were identified as originating from proteinaceous components of growth media and correlated to the presence of peptone, malt extract and yeast extract. Electrochemical impedance spectroscopy demonstrated significant increases in the charge transfer resistance for Fe(CN)63−/4− redox probes at glassy carbon electrodes in the presence of peptone-comprised media (130.3 Ω) compared to media-free buffer (50.4 Ω). Adsorption of the aforementioned media components to the electrode surface thus contributes to analytical interference through faradaic and non-faradaic processes. By adapting the growth media for analyte detection purposes, this study proves the feasibility of detecting OTC, as well as the use of dilution of the media to further decrease the interferent effects of growth media. A 50-fold dilution of the media provided a 96.7% recovery of the OTC peak current at 20 μM concentration. The empirical detection limit of OTC in 50-fold diluted media was determined to be 0.5 μM, which makes it applicable to current industrial OTC fermentation processes.
- Full Text:
- Date Issued: 2014
- Authors: Kruid, Jan , Fogel Ronen , Limson, Janice
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431206 , vital:72753 , xlink:href="https://doi.org/10.1016/j.electacta.2013.08.188"
- Description: Reports regarding the voltammetric properties of microbiological growth media are scarce in the literature and limited focus has been placed towards the application of electroanalysis for analyte monitoring in these complex media. This work aims to investigate the viability of voltammetry as a quantification method for analytes in microbiological growth media, using oxytetracycline (OTC) as a model analyte. Analysis of both commercially available and laboratory prepared growth media indicated the presence of interfering media components which produced anodic peaks at potentials ranging from ∼+0.85 V to ∼+1.30 V (vs. Ag/AgCl) under acidic conditions and ∼+0.62 V to ∼+1.35 V (vs. Ag/AgCl) under neutral pH. These peaks were identified as originating from proteinaceous components of growth media and correlated to the presence of peptone, malt extract and yeast extract. Electrochemical impedance spectroscopy demonstrated significant increases in the charge transfer resistance for Fe(CN)63−/4− redox probes at glassy carbon electrodes in the presence of peptone-comprised media (130.3 Ω) compared to media-free buffer (50.4 Ω). Adsorption of the aforementioned media components to the electrode surface thus contributes to analytical interference through faradaic and non-faradaic processes. By adapting the growth media for analyte detection purposes, this study proves the feasibility of detecting OTC, as well as the use of dilution of the media to further decrease the interferent effects of growth media. A 50-fold dilution of the media provided a 96.7% recovery of the OTC peak current at 20 μM concentration. The empirical detection limit of OTC in 50-fold diluted media was determined to be 0.5 μM, which makes it applicable to current industrial OTC fermentation processes.
- Full Text:
- Date Issued: 2014