Immobilization of tetra-amine substituted metallophthalocyanines at gold surfaces modified with mercaptopropionic acid or DTSP-SAMs
- Authors: Matemadombo, Fungisai , Westbroek, Philippe , Nyokong, Tebello , Ozoemena, Kenneth , De Clerck, Karen , Kiekens, Paul
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/283924 , vital:56003 , xlink:href="https://doi.org/10.1016/j.electacta.2006.08.027"
- Description: This paper shows that amine substituted cobalt phthalocyanine (CoTAPc) can be deposited on gold surfaces by using an interconnecting layer of a self-assembled monolayer (SAM) of mercaptopropionic acid or Lomant's reagent (dithiobis(N-succinimidyl propionate) (DTSP)). In both cases the new bond formed is obtained by the creation of an amide. The layers were characterized by electrochemistry and showed high coverage fractions (near 100%). Reductive and oxidative desorption of the SAMs limit the useful potential window from −0.6 to +0.5 V versus Ag|AgCl. The SAM-CoTAPc layers show electrocatalytic activities towards oxygen reduction through the Co(I) central metal ion. The amount of CoTAPc molecules deposited (obtained from the Co central metal ion activity in nitrogen purged solutions) revealed that the CoTAPc molecules are bonded in a perpendicular manner at the surface. Taking into account a surface of 200 Å2 for a flatly bonded MPc, this should result in a four times less amount of deposited CoTAPc compared to the experimental value obtained. Both methods showed good results and promising long-term stability and will be interesting tools for further research in surface modification and sensor development.
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- Date Issued: 2007
Implications of life history for genetic structure and migration rates of southern African coastal invertebrates: planktonic, abbreviated and direct development
- Authors: Teske, Peter R , Papadopoulos, Isabelle , Zardi, Gerardo I , McQuaid, Christopher D , Edkins, M T , Griffiths, C L , Barker, Nigel P
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/445447 , vital:74388 , https://doi.org/10.1007/s00227-007-0724-y
- Description: The amount of genetic structure in marine invertebrates is often thought to be negatively correlated with larval duration. However, larval retention may increase genetic structure in species with long-lived planktonic larvae, and rafting provides a means of dispersal for species that lack a larval dispersal phase. We compared genetic structure, demographic histories and levels of gene flow of regional lineages (in most cases defined by biogeographic region) of five southern African coastal invertebrates with three main types of larval development: (1) dispersal by long-lived planktonic larvae (mudprawn Upogebia africana and brown mussel Perna perna), (2) abbreviated larval development (crown crab Hymenosoma orbiculare) and (3) direct development (estuarine isopod Exosphaeroma hylecoetes and estuarine cumacean Iphinoe truncata). We hypothesized that H. orbiculare, having abbreviated larval development, would employ a strategy of larval retention, resulting in genetic structure comparable to that of the direct developers rather than the planktonic dispersers.
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- Date Issued: 2007
Inetvis: a graphical aid for the detection and visualisation of network scans
- Authors: Irwin, Barry V W , van Riel, Jean-Pierre
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430381 , vital:72687 , https://www.cs.ru.ac.za/research/g02V2468/publications/Irwin-VizSEC2007_draft.pdf
- Description: This paper presents an investigative analysis of network scans and scan detection algorithms. Visualisation is employed to review network telescope traffic and identify incidents of scan activity. Some of the identified phenomena appear to be novel forms of host discovery. The scan detection algorithms of Snort and Bro are critiqued by comparing the visualised scans with alert output. Where human assessment disa-grees with the alert output, explanations are sought after by analysing the detection algorithms. The algorithms of the Snort and Bro intrusion detection systems are based on counting unique connection attempts to destination addresses and ports. For Snort, notable false positive and false negative cases result due to a grossly oversimplified method of counting unique destination addresses and ports.
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- Date Issued: 2007
Insights into the surface and redox properties of single-walled carbon nanotube—cobalt (II) tetra-aminophthalocyanine self-assembled on gold electrode
- Authors: Ozoemena, Kenneth I , Nyokong, Tebello , Nkosi, Duduzile , Chambrier, Isabelle , Cook, Michael J
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/281258 , vital:55707 , xlink:href="https://doi.org/10.1016/j.electacta.2006.11.039"
- Description: This paper describes for the first time the electrochemical properties of redox-active self-assembled films of single-walled carbon nanotubes (SWCNTs) coordinated to cobalt(II)tetra-aminophthalocyanine (CoTAPc) by sequential self-assembly onto a preformed aminoethanethiol (AET) self-assembled monolayer (SAM) on a gold electrode. Both redox-active SAMs (Au-AET-SWCNT and Au-AET-SWCNT-CoTAPc) exhibited reversible electrochemistry in aqueous (phosphate buffer) solution. X-ray photoelectron spectroscopy (XPS) confirmed the appearance on the gold surface of the various elements found on the SAMs. Atomic force microscopy (AFM) images prove, corroborating the estimated electrochemical surface concentrations, that these SAMs lie normal to the gold surface. Electrochemical impedance spectroscopy (EIS) analyses in the presence of [Fe(CN)6]3−/4− as a redox probe revealed that the Au-AET-SWCNT-CoTAPc showed much lower (∼10 times) electron-transfer resistance (Ret) and much higher (∼10 times) apparent electron-transfer rate constant (kapp) compared to the Au-AET-SWCNT SAM. Interestingly, a preliminary electrocatalytic investigation showed that both SAMs exhibit comparable electrocatalytic responses towards the detection of dopamine in pH 7.4 phosphate buffer solutions (PBS). The electrochemical studies (cyclic voltammetry (CV) and EIS) prove that SWCNT greatly improves the electronic communication between CoTAPc and the Au electrode surface.
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- Date Issued: 2007
Intermediating Africa:
- Authors: Garman, Anthea
- Date: 2007
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/158806 , vital:40230 , https://hdl.handle.net/10520/EJC144693
- Description: In July, Vanity Fair, based in New York, did a unique special edition. Editor Graydon Carter explained how it came about: "Earlier this year, Mark Dowley, a marketing polymath at the Endeavour talent agency who has been involved with Bono's (Red) campaign from the start, called to inquire if I would be interested in having him guest edit an issue of the magazine. Interested? I'll say!".
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- Date Issued: 2007
Isolation of microsatellite markers for the endangered Knysna seahorse Hippocampus capensis and their use in the detection of a genetic bottleneck
- Authors: Galbusera, Peter H A , Gillemot, Sarah , Jouk, Phillippe , Teske, Peter R , Hellemans, Bart , Volckaert, Filip A M J
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/445678 , vital:74413 , https://doi.org/10.1111/j.1471-8286.2007.01688.x
- Description: We report the isolation and characterization of 15 (12 di‐, 1 tri‐ and 2 tetranucleotide) microsatellite markers from Hippocampus capensis, the Knysna seahorse. This marker set allows the detection of a genetic bottleneck as shown in a captive population. Furthermore, we test their genotyping potential in eight other seahorse taxa.
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- Date Issued: 2007
JM Coetzee and the ethics of reading:
- Authors: Marais, Mike
- Date: 2007
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144253 , vital:38325 , https://www.jstor.org/stable/pdf/26286886.pdf
- Description: One of Derek Attridge's principal concerns in J. M. Coetzee and the Ethics of Reading is the relationship that is established with alterity in the writing and reading of literary works. As is evident from the fact that some of the chapters in the book date back more than a decade, this is an abiding concern. Indeed, The Singularity of Literature, which also appeared in 2004, theorizes this relationship at great length. In it, Attridge describes the literary text as the emanation of an act of creation, that is, that mysterious experience in which the writer, who is located in culture's familiar modes of understanding, encounters something strange (in that it does not yet exist within the horizon that culture provides for thinking and feeling) and is required to resist the mind's tendency to reduce novelty by understanding it in terms of the familiar.
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- Date Issued: 2007
Lack of genetic differentiation among four sympatric southeast African intertidal limpets (Siphonariidae): phenotypic plasticity in a single species?
- Authors: Teske, Peter R , Barker, Nigel P , McQuaid, Christopher D
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/445461 , vital:74390 , https://doi.org/10.1093/mollus/eym012
- Description: Specimens of four sympatric intertidal limpet species (Siphonaria dayi, S. tenuicostulata, S. anneae and S. nigerrima) were collected from four localities on the east coast of South Africa and southern Mozambique. Their phylogenetic relationships were investigated using sequences of the mitochondrial COI gene and the intron-containing nuclear ATPSβ gene. Two closely related lineages were recovered, which grouped specimens on the basis of geography rather than morphology. One lineage was associated with the subtropical coastline of South Africa's east coast and the other with the tropical coastline of northeastern South Africa and southern Mozambique. This genetic discontinuity coincides with a biogeographic boundary located in the vicinity of Cape St Lucia. Combined genetic diversity of the four species was lower than that of three other southern African congeners, and fell within the range determined for single southern African marine mollusc species. We suggest that the four limpet species are in fact different morphotypes of a single species.
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- Date Issued: 2007
Language policy and planning: general constraints and pressures
- Authors: Wright, Laurence
- Date: 2007
- Language: English
- Type: text , article
- Identifier: vital:7043 , http://hdl.handle.net/10962/d1007385
- Description: preprint , The general idea of language policy and planning is easily expressed. Christopher Brumfit, for one, defines language planning as “The attempt to control the use, status, and structure of a language through a language policy developed by a government or other authority” (see the Oxford Companion to the English Language). The Random House Dictionary of the English Language concurs, but adds some detail: language planning is “the development of policies or programmes designed to direct or change language use, as through the establishment of an official language, the standardization or modernization of a language, or the development or alteration of a writing system”. Such definitions could easily be multiplied, and they differ only slightly in nuance and depth.Language Policy is the formal, often legally entrenched, expression of language planning.
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- Date Issued: 2007
Lazarus in the Constitutional Court: an exhumation of the exceptio doli generalis
- Authors: Glover, Graham B
- Date: 2007
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/70678 , vital:29688 , https://hdl.handle.net/10520/EJC53775
- Description: A landmark moment in the history of South African contract law was the emphatic interment of the exceptio doli generalis by Joubert JA in Bank of Lisbon and South Africa v De Ornelas 1988 (3) SA580 (A). Throughout most of the twentieth century, the exceptio doli generalis had been viewed as an equitable defence that allowed a defendant to resist a claim for performance under a contract when there was something unconscionable about the plaintiff's seeking to enforce the contract (or a clause thereof) in the specific circumstances of that case (see A J Kerr Principles of the Law of Contract 6 ed (2002) 637ff; P J Aronstam 'Unconscionable contracts: The South African solution?' (1979) 42 THRHR 21; P van Warmelo 'Exceptio doli' 1981 De Jure 202).
- Full Text: false
- Date Issued: 2007
Learning in a Changing World
- Authors: Lotz-Sisitka, Heila , O'Donoghue, Rob B , Robottom, Ian
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182679 , vital:43853 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122733 "
- Description: The year 2007 is a significant year for environmental education. It marks 30 years since the first internationally agreed principles of environmental education were developed at Tbilisi, commonly known as the Tbilisi Principles. It is also the year in which human beings apparently are finally ‘waking up’ to the fact that human-induced environmental change is causing impacts which are infinitely complex and difficult to resolve. This year, through various highly publicised and politicised events, people have begun to recognise that it is getting hot on planet Earth, and that the associated social, economic and environmental costs are profoundly disturbing. The Stern Review and the UN Intergovernmental Panel on Climate Change both firmly indicated that human-induced environmental change will threaten human economies and security in ways that are unprecedented in human history. Southern Africa, where this special edition of the EEASA Journal is being produced to coincide with the 25th anniversary of the existence of the Environmental Education Association of Southern Africa, and the hosting of the 4th World Environmental Education Congress, is one of the areas most vulnerable to the impacts of climate change. More than 70% of the people in southern Africa live in rural areas, and depend directly on natural resources for their livelihood and food security, making environment (and environmental education processes) a central concern in development discussions in the region. Patterns of global inequality are pronounced in the region, which has some of the poorest countries in the world. Out of its 25-year history, EEASA and its members, along with colleagues around the world, continue to seek ways of educating and empowering people to successfully participate in resolving environmental issues and create more sustainable and socially just living patterns. In drawing attention to our constant need to learn how to improve our understandings of environmental education and learning as the world around us changes, the World Environmental Education Congress organising committee chose to profile the question of ‘Learning in a Changing World’, by making this the theme of the Congress.
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- Date Issued: 2007
Light on a hill: building the Constitutional Court of South Africa, Bronwyn Law-Viljoen (Ed.): book review
- Authors: Simbao, Ruth K
- Date: 2007
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147324 , vital:38626 , https://0-hdl.handle.net.wam.seals.ac.za/10520/EJC31011
- Description: Light on a hill : Building the Constitutional Court of South Africa is a visually elegant book that claims to 'reflect the spirit of the Court and be a beautiful object in its own right' (p. 8). Certainly this book is striking, with its rich photographs by Angela Buckland, its fresh, breathable design by Adele Prins, and its broad format with lavish centerfolds. Reading the text is in many ways an enlightening process of understanding the conceptual underpinnings of the buildings that make up the Constitutional Court complex, but this process of reading takes a few twists and turns along the way.
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- Date Issued: 2007
Making visible constructions of dis/advantage through genealogical investigation: South African schooled literacies
- Authors: Prinsloo, Jeanne
- Date: 2007
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147869 , vital:38680 , DOI: 10.1080/02560040701398889
- Description: In this paper I assume the relevance of Foucauldian insights for conducting socio-cultural critique and I argue the significance of genealogical work in relation to understanding the present. Thus, I seek both to establish what could constitute a genealogical investigation and to illustrate this by describing and discussing a study, undertaken within a genealogical frame, into literacy practices within a specifically South African context. I investigated the differing schooled literacies in KwaZulu-Natal province in South Africa over three decades along the language lines of Afrikaans, English and Zulu. The findings propose that the differing sets of literacy practices validate different subjects – and that they are implicated in constructing dis/advantage.
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- Date Issued: 2007
Mechanisms for multimodality: taking fiction to another dimension
- Authors: Glass, Kevin R , Bangay, Shaun D , Alcock, Bruce
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/433226 , vital:72953 , https://doi.org/10.1145/1294685.1294708
- Description: We present methods for automatically constructing representations of fiction books in a range of modalities: audibly, graphically and as 3D virtual environments. The correspondence between the sequential ordering of events against the order of events presented in the text is used to correctly resolve the dynamic interactions for each representation. Synthesised audio created from the fiction text is used to calibrate the base time-line against which the other forms of media are correctly aligned. The audio stream is based on speech synthesis using the text of the book, and is enhanced using distinct voices for the different characters in a book. Sound effects are included automatically. The graphical representation represents the text (as subtitles), identifies active characters and provides visual feedback of the content of the story. Dynamic virtual environments conform to the constraints implied by the story, and are used as a source of further visual content. These representations are all aligned to a common time-line, and combined using sequencing facilities to provide a multimodal version of the original text.
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- Date Issued: 2007
Message to the New Zealand Old Rhodian Reunion
- Authors: Badat, Saleem
- Date: 2007
- Subjects: Rhodes University
- Language: English
- Type: text
- Identifier: vital:7647 , http://hdl.handle.net/10962/d1015775
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- Date Issued: 2007
Microwave synthesis and photophysics of new tetrasulfonated tin (II) macrocycles
- Authors: Khene, Samson , Ogunsipe, Abimbola , Antunes, Edith M , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/281269 , vital:55708 , xlink:href="https://doi.org/10.1142/S108842460700014X"
- Description: This work reports on the microwave synthesis of tetrasulfonated tin phthalocyanine and tetrasulfonated tin α,β,γ-tetrabenzcorrole. The latter was only formed at low ratios (more than 1:8) of 4-sulfophthalic acid to urea. Both complexes are aggregated in aqueous media, but can be partly or fully disaggregated by the addition of Triton X-100. The α,β,γ-tetrabenzcorrole complex has lower triplet life times and yields, while the binding constant and quenching (of bovine serum albumin) constant are lower for α,β,γ-tetrabenzcorrole compared to tetrasulfonated tin phthalocyanine.
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- Date Issued: 2007
More media for Southern Africa?: the place of politics, economics and convergence in developing media density
- Authors: Berger, Guy
- Date: 2007
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147825 , vital:38676 , https://0-doi.org.wam.seals.ac.za/10.1080/02560240485310041
- Description: In line with global trends, media in Southern Africa in the past decade has been moving slowly towards mergers, partnerships and multi-platform publishing. Driven by politics and facilitated by technology, the process has had to confront the difficulty of establishing viable economic models, the lack of regional integration within Southern African countries, and what is sometimes a difficult political environment. Markets remain largely national or local and economically weak. Print media faces huge hurdles. Broadcast media density is improving, partly through noncommercial mechanisms. News websites are understaffed, lacking in viable survival strategies and skills, and are incompletely integrated with parent media platforms. Economic pressures, however, are likely to force Southern African media operations into greater synergies in search of survival. The various convergences entailed may increase media density.
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- Date Issued: 2007
Morphological and genetic analyses suggest that southern African crown crabs, Hymenosoma orbiculare, represent five distinct species
- Authors: Edkins, M T , Teske, Peter R , Papadopoulos, Isabelle , Griffiths, C L
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/445701 , vital:74415 , https://www.jstor.org/stable/20107852
- Description: The crown crab, Hymenosoma orbiculare, occurs all along the coast of southern Africa displays great morphological variation across this range. To determine whether the species c several distinct taxonomic units, H. orbiculare were collected from 18 estuaries and lagoons Walvis Bay in Namibia and Kosi Bay in north-eastern South Africa. Open ocean individua also obtained from False Bay in south-western South Africa. Morphological and genet mitochondrial DNA) comparisons were carried out between individuals from all locatio monophyletic clusters were identified on the basis of genetic data, each confined to specific of the distribution range. Morphological data supported the distinctness of each of these clus typical H. orbiculare, characterized by large size (maximum carapace width 28 mm) and of the characteristic ornamentations of other morphotypes, occurred in estuaries and lag along the west and south coasts. False Bay deep-water individuals were of two forms.
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- Date Issued: 2007
Negotiating the Good Life
- Authors: Tabensky, Pedro
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/305688 , vital:58604 , xlink:href="http://10.1007/s10677-006-9030-x"
- Description: Book Review: Mark A. Young asks: “Is there a problem with community in America?” (p. 1). Agreeing with Robert Putnam’s views, embodied in Bowling Alone: The Collapse and Revival of American Community (New York: Touchstone Press, 2000), regarding the breakdown of communal values in the US, but not with his nostalgic recommendations regarding the ‘good old days’ of univocal homogenous communities, Young proposes an alternative solution to Putnam’s, starting from Aristotle’s sophisticated account of the self/community relation and drawing important insights from Alasdair MacIntyre, Charles Taylor, Amitai Etzione, Paul Ricoeur, Michael Sandel and especially Hannah Arendt.
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- Date Issued: 2007
Nesting success and survival rates of suburban Olive Thrushes (Turdus olivaceus olivaceus).
- Authors: Bonnevie, Bo T
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/448299 , vital:74720 , https://doi.org/10.2989/OSTRICH.2007.78.2.19.99
- Description: Adult survival rates of suburban Olive Thrushes (Turdus olivaceus) were estimated from the proportion of adults and juveniles in mist-net samples from the Eastern Cape and Western Cape provinces of South Africa. These survival rates were compared to an estimate from recovery data. Reproductive rate, clutch size, nesting success and survival rate of dependent fledglings were estimated from breeding records in the Eastern Cape. These data were used to estimate survival rate of independent fledglings. The estimated adult survival rate in this region was high and the clutch size was small, compared to those of the Blackbird (Turdus merula) in Europe. Dispersal patterns from recapture and recovery data, and the relatively low survival rates of juvenile birds, suggest that fledglings are most vulnerable when they reach independence and leave their natal territories.
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- Date Issued: 2007