The Electrochemical Behavior of Gold Nanoparticle‐Tantalum (V) Phthalocyanine Composites
- Authors: Chauke, Vongani , Chidawanyika, Wadzanai J U , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247915 , vital:51629 , xlink:href="https://doi.org/10.1002/elan.201000521"
- Description: The formation of gold nanoparticle (AuNP) composites with tantalum phthalocyanines (TaPc) complexes {1a and 1b (Figure 1)} is reported. The TaPc-AuNPs conjugates were characterised by atomic force microscopy (AFM) and transmission electron microscopy. The AFM analyses show that conjugates of TaPc with AuNPs are more aggregated when compared to AuNPs alone. The conjugates and TaPc complexes were immobilized on a gold electrode by drop and dry method and these were characterized by electrochemical impedance spectroscopy. The charge transfer behaviour of AuNPs was enhanced in the presence of TaPc complexes. All the modified electrodes showed electrocatalytic oxidation of bisphenol A. The limits of detection for complexes 1a and 1b were 4.78×10−10 and 2.76×10−10 mol L−1, respectively.
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- Date Issued: 2011
The experiences of Fringe producers at the South African National Arts Festival: production, profits and non-market benefits
- Authors: Snowball, Jeanette D , Antrobus, Geoffrey G
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143123 , vital:38203 , DOI: 10.1080/10137548.2009.9687901
- Description: Unlike the performing arts generally, festivals and special events have been growing in popularity worldwide: since the 1980s there has been an explosion of the number of festival of all types, not just arts festivals, but folk festivals, harvest festivals, food festivals, family festivals, carnivals, literary festivals – the list is long. It is estimated that there are more than 300 festivals in the UK (British Federation of Festivals 2004), 1300 in Australia (Johnson et al 2005) and more than 5000 in the US (Blumenthal 2002).
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- Date Issued: 2011
The future of e-Service provision in Marginalised Areas: Online Negotiation.
- Authors: Jere, Norbert R , Thinyane, Mamello , Terzoli, Alfredo
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431332 , vital:72765 , https://citeseerx.ist.psu.edu/document?repid=rep1type=pdfdoi=5d49a8014f769a529d821556ad204f1b25a97dcb#page=245
- Description: As the amount of commercial transactions carried out on t he Internet in-creases, the interest to partially or totally automate the negotiation of the terms of these transactions has rapidly become an interesting research topic. Several e-marketing strategies through various online websites have been developed. In rural communities e-services applications such as e-commerce, ehealth, e-judiciary and e-government have been devel-oped. However, most of these applications are failing to fully benefit the people in the societies because they are no modifications which are done to the applications as technology changes. This paper discusses the de-velopment of an intelligent negotiation module to enhance an e-commerce platform. The paper explains a negotiation application that has been developed and plugged to any existing e-Commerce shopping por-tal for the Dwesa Community in the Eastern cape province of South Africa and proposes an architecture for all other e-Services. This project ex-plained is undertaken within the Siyakhula Living Lab.
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- Date Issued: 2011
The laws of Lerotholi: role and status of codified rules of custom in the kingdom of Lesotho
- Authors: Juma, Laurence
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/128810 , vital:36162 , https://heinonline.org/HOL/P?h=hein.journals/pacinlwr23ampi=94
- Description: The status of customary law in African societies is diminished by factors, most of which are generated by the machinery of the modern state. But its mantle, kept alive by neo-traditional scholarship and a commitment to multiculturalism in the post-independence era, has nevertheless sustained an active discussion on its relevance to the future of law and the general administration of justice in African states.2
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- Date Issued: 2011
The next decade of environmental science in South Africa: a horizon scan
- Authors: Shackleton, Charlie M , Scholes, Robert J , Vogel, Coleen , Wynberg, Rachel , Abrahamse, Tanya , Shackleton, Sheona E , Ellery, William F N , Gambiza, James
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/157124 , vital:40088 , https://doi.org/10.1080/03736245.2011.563064
- Description: Environmental systems are in constant flux, with feedbacks and non-linearities catalysed by natural trends and shocks as well as human actions. This poses challenges for sustainable management to promote human well-being. It requires environmental understanding and application that can accommodate such fluxes and pressures, as well as knowledge production systems and institutions that produce graduates with appropriate skills. In this article we consider these challenges in the South African context. Firstly, we summarise six significant environmental realisations from the last decade of environmental science internationally and question what they mean for the teaching of environmental science and research into environmental systems in South Africa in the near future. We then consider these lessons within the context of a horizon scan of near-term pressing environmental issues in South Africa. These include wateruse efficiency, poverty, food security, inequities in land and resource access, urbanisation, agrochemicals and water quality, promoting human well-being and economic adaptability in the face of climate change, and imbuing stronger environmental elements and stewardship into the integrated development planning processes and outcomes. Lastly, we consider the knowledge areas and skills that environmental graduates will require to be able to confront these problems in South Africa and simultaneously contribute to international debates and understandings around the complexity of environmental systems and how to manage them.
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- Date Issued: 2011
The origin and development of the Nyl River floodplain wetland, Limpopo Province, South Africa: trunk–tributary river interactions in a dryland setting
- Authors: McCarthy, T S , Tooth, Stephen , Jacobs, Zenobia , Rowberry, Matthew D , Thompson, Mark , Brandt, Dion , Hancox, P John , Marren, Philip M , Woodborne, Stephan , Ellery, William F N
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144321 , vital:38331 , DOI: 10.1080/03736245.2011.619324
- Description: The Nyl River floodplain wetland, one of South Africa's largest floodplain wetlands and a Ramsar site of international conservation importance, is located in an area of long-term and still active valley sediment accumulation. Creation of accommodation space for sedimentation has previously been attributed to tectonic controls, but new investigations reveal that a more likely cause is progradation of coarse-grained tributary fans across the narrow river valley downstream of the main area of floodplain wetland. Obstruction of trunk river flow and sediment transfer by these tributary fans has led to backponding and upstream gradient reduction and to accumulation of valley fills up to ∼35 m thick. Chronological control for the timing and rate of sediment accumulation is limited, but we hypothesise that a semi-arid to arid climate, characterised by asynchronous trunk–tributary activity that results in marked discontinuities in downstream water and sediment transfer, is likely to have been a key control. These interpretations are supported by other studies of dryland rivers globally and the findings add to our growing understanding of the controls on the origin and development of southern African wetlands, particularly by demonstrating how the combination of a particular physiography and a dryland climate can impart some distinctive geomorphological characteristics.
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- Date Issued: 2011
The PINIT domain of PIAS3: structure-function analysis of its interaction with STAT3
- Authors: Mautsa, Nicodemus , Prinsloo, Earl , Tastan Bishop, Özlem , Blatch, Gregory L
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148082 , vital:38708 , DOI: 10.1002/jmr.1111
- Description: The protein inhibitor of activated signal transducer and activator of transcription 3 (PIAS3) regulates the transcriptional activity of signal transducer and activator of transcription 3 (STAT3) which regulates transcription of genes involved in cell growth, proliferation and apoptosis. The conserved proline, isoleucine, asparagine, isoleucine, threonine (PINIT) domain of PIAS3 is thought to promote STAT3–PIAS3 interaction.
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- Date Issued: 2011
The problems of proving actual or apparent bias: an analysis of contemporary developments in South Africa
- Authors: Okpaluba, Chuks , Juma, Laurence
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/127498 , vital:36017 , https://doi.org/10.17159/1727-3781/2011/v14i7a2616
- Description: This article takes a critical look at the divergent approaches of courts in constructing the meaning of actual and apparent bias in adjudicative contexts. It argues that while proving actual bias on the part of an adjudicator may not always be easy and parties often revert to apprehended bias, an allegation of bias in any adjudication process is a matter that courts take very seriously. This notwithstanding, the courts have failed to consistently demarcate the necessary elements and threshold of proof that complainants must overcome to secure a successful challenge of decisions based on adjudicative impartiality. Upon critical evaluation of the decisions on the subject so far rendered, this article suggests that the pattern which has seemingly emerged is that which weighs the allegations of bias against the presumption of impartiality and the requirements of the double reasonableness test.
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- Date Issued: 2011
The role of eutrophication in the biological control of water hyacinth, Eichhornia crassipes, in South Africa
- Authors: Coetzee, Julie A , Hill, Martin P
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69263 , vital:29474 , https://doi.org/10.1007/s10526-011-9426-y
- Description: South Africa has some of the most eutrophic aquatic systems in the world, as a result of the adoption of an unnecessarily high 1 mg l-1 phosphorus (P) standard for all water treatment works in the 1970 s. The floating aquatic macrophyte, water hyacinth (Eichhornia crassipes (Mart.) Solms (Pontederiaceae), has taken advantage of these nutrient rich systems, becoming highly invasive and damaging. Despite the implementation of a biological control programme in South Africa, water hyacinth remains the worst aquatic weed. A meta-analysis of published and unpublished laboratory studies that investigated the combined effect of P and nitrogen (N) water nutrient concentration and control agent herbivory showed that water nutrient status was more important than herbivory in water hyacinth growth. Analysis of long-term field data collected monthly from 14 sites around South Africa between 2004 and 2005 supported these findings. Therefore, the first step in any water hyacinth control programme should be to reduce the nutrient status of the water body.
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- Date Issued: 2011
The synthesis and fluorescence behaviour of new unsymmetrically mono-functionalized carboxy Ge, Ti and Sn phthalocynines
- Authors: Masilela, Nkosiphile , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/246977 , vital:51534 , xlink:href="https://doi.org/10.1016/j.dyepig.2011.03.026"
- Description: This work reports on the synthesis and fluorescence behaviour of novel unsymmetrically substituted monocarboxy germanium ((OH)2GeMCPc, 3), titanium (OTiMCPc 4) and tin ((ac)2SnMCPc, 5) phthalocyanines. The fluorescence quantum yields ranged from 0.09 to 0.14. The fluorescence lifetimes were found to be higher for the complex with higher fluorescence quantum yield value. Higher fluorescence quantum yields and lifetimes were obtained for the (ac)2SnMCPc complex (5), followed by OTiMCPc complex (4), and the lowest fluorescence quantum yield and lifetime were observed for (OH)2GeMCPc (3).
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- Date Issued: 2011
The synthesis and photophysical properties of peripherally and non-peripherally substituted ball-type Mg (II) and Zn (II) phthalocyanines
- Authors: Canlica, Mevlude , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/248417 , vital:51684 , xlink:href="https://doi.org/10.1039/C0DT00920B"
- Description: Newly synthesized ball-type Zn(II) and Mg(II) phthalocyanines containing four 1,1′-binaphthol substituents at peripheral and non-peripheral positions are presented. The structures of the synthesized compounds were characterized by using elemental analysis, UV-vis, FT-IR, 1H-NMR and mass spectroscopies. The ΦF values were 0.33, 0.08, 0.20 and 0.08 for 6–9, respectively. The ΦT values were 0.56, 0.85, 0.64 and 0.88 for 6–9, respectively. All the complexes showed reasonably large triplet lifetimes with τT values of 710 (6), 170 (7), 1490 (8) and 380 μs (9) in DMSO. These complexes offer potential as photosensitizers in photodynamic therapy.
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- Date Issued: 2011
The use of experimental design in the development of an HPLC–ECD method for the analysis of captopril
- Authors: Khamanga, Sandile M , Walker, Roderick B
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184056 , vital:44163 , xlink:href="https://doi.org/10.1016/j.talanta.2010.11.025"
- Description: An accurate, sensitive and specific high performance liquid chromatography–electrochemical detection (HPLC–ECD) method that was developed and validated for captopril (CPT) is presented. Separation was achieved using a Phenomenex® Luna 5 μm (C18) column and a mobile phase comprised of phosphate buffer (adjusted to pH 3.0): acetonitrile in a ratio of 70:30 (v/v). Detection was accomplished using a full scan multi channel ESA Coulometric detector in the “oxidative-screen” mode with the upstream electrode (E1) set at +600 mV and the downstream (analytical) electrode (E2) set at +950 mV, while the potential of the guard cell was maintained at +1050 mV. The detector gain was set at 300. Experimental design using central composite design (CCD) was used to facilitate method development. Mobile phase pH, molarity and concentration of acetonitrile (ACN) were considered the critical factors to be studied to establish the retention time of CPT and cyclizine (CYC) that was used as the internal standard. Twenty experiments including centre points were undertaken and a quadratic model was derived for the retention time for CPT using the experimental data. The method was validated for linearity, accuracy, precision, limits of quantitation and detection, as per the ICH guidelines. The system was found to produce sharp and well-resolved peaks for CPT and CYC with retention times of 3.08 and 7.56 min, respectively. Linear regression analysis for the calibration curve showed a good linear relationship with a regression coefficient of 0.978 in the concentration range of 2–70 μg/mL. The linear regression equation was y = 0.0131x + 0.0275. The limits of detection (LOQ) and quantitation (LOD) were found to be 2.27 and 0.6 μg/mL, respectively. The method was used to analyze CPT in tablets. The wide range for linearity, accuracy, sensitivity, short retention time and composition of the mobile phase indicated that this method is better for the quantification of CPT than the pharmacopoeial methods.
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- Date Issued: 2011
The xfn connection management and control protocol
- Authors: Foss, Richard , Gurdan, Robby , Klinkradt, Bradley , Chigwamba, Nyasha
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427137 , vital:72417 , https://www.aes.org/e-lib/browse.cfm?elib=16143
- Description: With the advent of digital networks that link audio devices, there is a need for a protocol that integrates control and connection management, enables the streaming of all media content such as audio and video between devices from different manufacturers, and that provides a common approach to the control of these devices. This paper describes such a protocol, named XFN, currently being standardized as part of the AES X170 project. XFN is an IP-based peer to peer network protocol, in which any device on the network may send or receive connection management, control, and monitoring messages. Essential to the XFN protocol is the fact that each parameter in a device can be addressed via a hierarchical structure that reflects the functional layout of the device.
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- Date Issued: 2011
The ‘refeudalisation’ or the ‘return of the repressed’ of the public sphere?:
- Authors: Garman, Anthea
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159857 , vital:40350 , DOI: 10.1080/02560054.2011.621293
- Description: The prevalent depiction of the heyday of the public sphere and its fall from grace under present-day, publicity-ridden, highly commercialised media, with their individualised address of entertainment, is an inadequate conception of today's complex public spheres. The 18th-century bourgeois public sphere had a number of features – often repressed in practice and in theory – which were bound to have their outcomes and a/effects in the public spaces, practices and vehicles we experience today.
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- Date Issued: 2011
Theiler’s murine encephalomyelitis virus infection induces a redistribution of heat shock proteins 70 and 90 in BHK-21 cells, and is inhibited by novobiocin and geldanamycin:
- Authors: Mutsvunguma, Lorraine Z , Moetlhoa, Boitumelo , Edkins, Adrienne L , Luke, Garry A , Blatch, Gregory L , Knox, Caroline M
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165085 , vital:41207 , DOI: 10.1007/s12192-011-0262-x
- Description: Theiler’s murine encephalomyelitis virus (TMEV) is a positive-sense RNA virus belonging to the Cardiovirus genus in the family Picornaviridae. In addition to other host cellular factors and pathways, picornaviruses utilise heat shock proteins (Hsps) to facilitate their propagation in cells. This study investigated the localisation of Hsps 70 and 90 in TMEV-infected BHK-21 cells by indirect immunofluorescence and confocal microscopy. The effect of Hsp90 inhibitors novobiocin (Nov) and geldanamycin (GA) on the development of cytopathic effect (CPE) induced by infection was also examined. Hsp90 staining was uniformly distributed in the cytoplasm of uninfected cells but was found concentrated in the perinuclear region during late infection where it overlapped with the signal for non-structural protein 2C within the viral replication complex.
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- Date Issued: 2011
Towards a standard model for networked audio devices
- Authors: Eales, Andrew , Foss, Richard
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427151 , vital:72418 , https://www.aes.org/e-lib/online/browse.cfm?elib=16144
- Description: Different control protocols for networked audio devices typically emphasize particular aspects of a device, such as the representation of parameter data, or a representation of the functional structure of a device. A sophisticated device model must represent parameter data, device structure and the visual presentation of controls. Parameter data should be related to the device structure, while also being represented within a flexible, logical hierarchy. The development of a standard device model is proposed and discussed with reference to the OSC, IEC62379, ACN and X170 control protocols. This abstract model is independent of any specific control protocol, and provides support for interoperability between control protocols. The proposed model is also discussed within the context of an object-based approach to service enumeration and control using an associative, shared memory model.
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- Date Issued: 2011
Use and users of municipal commonage around three small towns in the Eastern Cape, South Africa
- Authors: Davenport, Nicholas A , Shackleton, Charlie M , Gambiza, James
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181116 , vital:43700 , xlink:href="https://doi.org/10.1016/j.jenvman.2010.11.003"
- Description: Municipal commonages surround many small towns throughout South Africa, and are an integral component of the national land reform programme. But little is known about their extent, use or value, and most appear to have limited or no management or investment. This paper reports on a survey of randomly selected households in three small towns in the Eastern Cape to ascertain the extent and purpose of use of municipal commonages. Between 27% and 70% of urban households used commonage depending on site. Key resources used were fuelwood, medicinal plants, and grazing of livestock. Typically, commonage using households were poorer and less educated than other urban residents, although the profile of users is unique for each town. Given the extensive use of commonage resources, and their contribution to the livelihoods of the poor, local municipalities need to develop and implement sound management strategies that account for all users of commonages, rather than the oft encountered focus on livestock owners and production.
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- Date Issued: 2011
Using molecules and morphology to infer the phylogenetic relationships and evolutionary history of the Dirini (Nymphalidae: Satyrinae), a tribe of butterflies endemic to Southern Africa
- Authors: Price, Benjamin W , Villet, Martin H , Walton, Shaun M , Barker, Nigel P
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/442397 , vital:73981 , https://doi.org/10.1111/j.1365-3113.2010.00560.x
- Description: The first empirically supported phylogenetic hypothesis of relationships for the southern African endemic butterfly tribe Dirini is presented. Data derived from the morphology and ecology of the adults and immature stages (33 characters), and portions of the mitochondrial gene cytochrome oxidase I (COI) and the nuclear genes elongation factor 1α (EF1α) and wingless (WG) (totalling 1734 bp) were used to infer the relationships of the in‐group genera. An expanded molecular dataset using four genera from the Nymphalini and Satyrini to root the tree, and three genera from the Melanitini to test the monophyly of the tribe, was analysed using parsimony and Bayesian methods. Estimates of divergence times were calculated using two fossil calibrations under a relaxed molecular clock model. The monophyly of the tribe and each in‐group genus were strongly supported. Key findings are the sister‐taxon relationship of Aeropetes and Tarsocera, the apparent simultaneous or nearly simultaneous radiation of four lineages, the polyphyly of the species within Torynesis, and the apparent trans‐Atlantic dispersal of the ancestors of Manataria about 40 Ma. Estimates of divergence times indicate that the tribe has undergone two major radiations since its origin: the first when they left forest habitats in the mid–late Oligocene, shortly after the radiation of the grasses (Poaceae), and the second in the early‐middle Pliocene, coinciding with the aridification of southern Africa and the spread of conditions that favoured C4 grasses over the C3 grasses that dirine larvae prefer to eat. The high species diversity within the tribe appears to be partly a taxonomic artefact that may have resulted from the misinterpretation of climate-related phenotypic variation within extant species. Relocation and breeding experiments should test this hypothesis.
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- Date Issued: 2011
Violence, postcolonial fiction, and the limits of sympathy:
- Authors: Marais, Mike
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143993 , vital:38301 , DOI: 10.1353/sdn.2011.0034
- Description: In this article, I consider the implications for fiction of Slavo Zizek’s argument that the violence of individual subjects is informed by ‘symbolic violence’ (1-2), that is, the distortions concomitant on languages’s constitutive, rather than merely referential, relation to the world.
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- Date Issued: 2011
Voltammetry and electrochemical impedance spectroscopy of gold electrodes modified with CdTe quantum dots and their conjugates with nickel tetraamino phthalocyanine
- Authors: Khene, Samson , Moeno, Sharon , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247187 , vital:51554 , xlink:href="https://doi.org/10.1016/j.poly.2011.06.002"
- Description: This work reports on the synthesis of conjugates of cadmium telluride quantum dots (CdTe-QDs) caped with thioglycolic acid and peripherally substituted nickel tetraamino phthalocyanine (NiTAPc) complex. The conjugates are characterized using cyclic (CV) and differential pulse (DPV) voltammetries, electrochemical impedance spectroscopy, X-ray powder diffraction, infrared spectroscopy, Raman spectroscopy, atomic force microscopy and time correlated single photon counting. CV and DPV show that NiTAPc stabilizes the CdTe QDs against oxidation to metallic products.
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- Date Issued: 2011