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Newsroom convergence at the Mail & Guardian: a case study

- Van Noort, Elvira Esmeralda

No other world: the poetry of Don Maclennan

- Robinson, Brendon Kimbale

  • Authors: Robinson, Brendon Kimbale
  • Date: 2008
  • Subjects: Maclennan, Don Maclennan, Don -- Criticism and interpretation South African poetry (English) -- History and criticism
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:2221 , http://hdl.handle.net/10962/d1002264
  • Description: This is a study of the poetry of Don Maclennan in four chapters. Chapter One explores the poetry's deep involvement with the immediate world, and with the being that encounters it. Chapter Two examines the corpus's mistrust of abstract thought, and its suggestions for alternative ways of intepreting (or at least approaching an interpretation of) our existential situation. Chapter Three deals with Maclennan's writing on the subject of death, while the final chapter looks at the response of the poetry to the fact of death: put simply, this is to learn to love the situation we are in, and to record our thoughts for future generations, thus reaching beyond death to share with others the necessarily unique experience of our one and only life.
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Normative indications for Xhosa-speaking unskilled workers on the trail making test and the stroop test

- Andrews, Karen Anne Hope

  • Authors: Andrews, Karen Anne Hope
  • Date: 2008
  • Subjects: Neuropsychology , Neuropsychological tests -- Sex differences , Educational tests and measurements -- Sex differences , Xhosa (African people) -- Education
  • Language: English
  • Type: Thesis , Masters , MCom
  • Identifier: vital:2926 , http://hdl.handle.net/10962/d1002435 , Neuropsychology , Neuropsychological tests -- Sex differences , Educational tests and measurements -- Sex differences , Xhosa (African people) -- Education
  • Description: The aim of the study was to produce preliminary normative indications for the Trail Making Test and the Stroop Test, administered in English, on a non-clinical sample of black, Xhosa-speaking, unskilled individuals (N = 33), with an educational level of 11 – 12 years, in two age categories (18 –29 and 30 – 40 years). The sample was equally distributed for gender and level of education. Participants, who were required to have a basic proficiency in English, were from traditionally black township schools with relatively disadvantaged quality of education. Within-sample age and gender effects were investigated. There were no significant age effects on the Trail Making Test, whereas there was one significant difference between age groups on the Stroop Test with respect to the Color-Word task, and a result that strongly approached significance on the Word task, with the younger group performing better than the older group. There were no significant gender effects on the Trail Making Test, whereas there was one significant difference between genders on the Stroop Test with respect to the Word task, and a result that approached significance on the Color task, with females performing better than males. Normative indications for both measures were compared to available normative data on western populations with higher levels and more advantaged quality of education. This comparison revealed consistently poorer performances for both the Trail Making Test and the Stroop Test, confirming the need for localised normative datasets to facilitate accurate neuropsychological diagnoses on culturally disadvantaged individuals.
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Not an astute political thinker or visionary

- Maylam, Paul

  • Authors: Maylam, Paul
  • Date: 2008
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/449993 , vital:74874 , https://www.scielo.org.za/pdf/hist/v53n1/19.pdf
  • Description: Colin Eglin served as member of parliament for thirty-three years (1958-1961, 1974- 2004), under seven prime ministers or presidents (from Strijdom to Mbeki), and under five different constitutions (the Union Constitution, the Republican, the Tricameral, the 1994 Interim, and the final 1996 Constitution). Moreover during his parliamentary career he belonged to no less than six political parties (the United Party, the Progressive Party, the Progressive Reform Party, the Progressive Federal Party, the Democratic Party, and the Democratic Alliance). This is not to suggest at all that Eglin was one of those party-hopping opportunists that have come to bedevil South African politics in recent years. Far from it – Eglin only once switched parties, being one of the original “Prog” MPs who left the decaying, ever more conservative United Party in 1959 and became one of the founding MPs of the Progressive Party. Thereafter all his changing party affiliations would result from mergers and realignments in parliamentary opposition politics – realignments that always kept the “Progs” at the core.
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Nuclear translocation of the phosphoprotein Hop (Hsp70/Hsp90 organizing protein) occurs under heat shock, and its proposed nuclear localization signal is involved in Hsp90 binding

- Daniel, Sheril, Bradley, Graeme, Longshaw, Victoria M, Söti, Csaba, Csermely, Peter, Blatch, Gregory L

  • Authors: Daniel, Sheril , Bradley, Graeme , Longshaw, Victoria M , Söti, Csaba , Csermely, Peter , Blatch, Gregory L
  • Date: 2008
  • Language: English
  • Type: Article
  • Identifier: vital:6472 , http://hdl.handle.net/10962/d1005951 , http://dx.doi.org/10.1016/j.bbamcr.2008.01.014
  • Description: The Hsp70–Hsp90 complex is implicated in the folding and regulation of numerous signaling proteins, and Hop, the Hsp70–Hsp90 Organizing Protein, facilitates the association of this multichaperone machinery. Phosphatase treatment of mouse cell extracts reduced the number of Hop isoforms compared to untreated extracts, providing the first direct evidence that Hop was phosphorylated in vivo. Furthermore, surface plasmon resonance (SPR) spectroscopy showed that a cdc2 kinase phosphorylation mimic of Hop had reduced affinity for Hsp90 binding. Hop was predominantly cytoplasmic, but translocated to the nucleus in response to heat shock. A putative bipartite nuclear localization signal (NLS) has been identified within the Hsp90-binding domain of Hop. Although substitution of residues within the major arm of this proposed NLS abolished Hop–Hsp90 interaction as determined by SPR, this was not sufficient to prevent the nuclear accumulation of Hop under leptomycin-B treatment and heat shock conditions. These results showed for the first time that the subcellular localization of Hop was stress regulated and that the major arm of the putative NLS was not directly important for nuclear translocation but was critical for Hop–Hsp90 association in vitro. We propose a model in which the association of Hop with Hsp90 and the phosphorylated status of Hop both play a role in the mechanism of nucleo-cytoplasmic shuttling of Hop.
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Oceanic dispersal barriers, adaptation and larval retention: an interdisciplinary assessment of potential factors maintaining a phylogeographic break between sister lineages of an African prawn

- Teske, Peter R, Papadopoulos, Isabelle, Newman, Brent K, Dworschak, Peter C, McQuaid, Christopher D, Barker, Nigel P

  • Authors: Teske, Peter R , Papadopoulos, Isabelle , Newman, Brent K , Dworschak, Peter C , McQuaid, Christopher D , Barker, Nigel P
  • Date: 2008
  • Language: English
  • Type: Article
  • Identifier: vital:6546 , http://hdl.handle.net/10962/d1006002 , http://dx.doi.org/10.1186/1471-2148-8-341
  • Description: Background. Genetic breaks separating regional lineages of marine organisms with potentially high broadcasting abilities are generally attributed either to dispersal barriers such as currents or upwelling, or to behavioural strategies promoting self-recruitment. We investigated whether such patterns could potentially also be explained by adaptations to different environmental conditions by studying two morphologically distinguishable genetic lineages of the estuarine mudprawn Upogebia africana across a biogeographic disjunction in south-eastern Africa. The study area encompasses a transition between temperate and subtropical biotas, where the warm, southward-flowing Agulhas Current is deflected away from the coast, and its inshore edge is characterised by intermittent upwelling. To determine how this phylogeographic break is maintained, we estimated gene flow among populations in the region, tested for isolation by distance as an indication of larval retention, and reared larvae of the temperate and subtropical lineages at a range of different temperatures. Results. Of four populations sampled, the two northernmost exclusively included the subtropical lineage, a central population had a mixture of both lineages, and the southernmost estuary had only haplotypes of the temperate lineage. No evidence was found for isolation by distance, and gene flow was bidirectional and of similar magnitude among adjacent populations. In both lineages, the optimum temperature for larval development was at about 23°C, but a clear difference was found at lower temperatures. While larvae of the temperate lineage could complete development at temperatures as low as 12°C, those of the subtropical lineage did not complete development below 17°C. Conclusion. The results indicate that both southward dispersal of the subtropical lineage inshore of the Agulhas Current, and its establishment in the temperate province, may be limited primarily by low water temperatures. There is no evidence that the larvae of the temperate lineage would survive less well in the subtropical province than in their native habitat, and their exclusion from this region may be due to a combination of upwelling, short larval duration with limited dispersal potential near the coast, plus transport away from the coast of larvae that become entrained in the Agulhas Current. This study shows how methods from different fields of research (genetics, physiology, oceanography and morphology) can be combined to study phylogeographic patterns.
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On academic freedom

- Pityana, Barney

  • Authors: Pityana, Barney
  • Date: 2008
  • Subjects: Academic Freedom -- South Africa Universities and colleges -- South Africa Equality Liberty Education and state -- South Africa Education, Higher -- South Africa
  • Language: English
  • Type: text
  • Identifier: http://hdl.handle.net/10962/751 , vital:19987
  • Description: Traditionally, higher education has formed the vanguard of ideological persuasion and even indoctrination, in support of political and social change. We should not be surprised then, that the converse also applies. Where an existing order is threatened, those intellectuals who do not toe the line are often vilified, marginalised and even worse. Many of the great revolutions have commenced with a thorough purging of intellectuals. History will testify to that. Furthermore, where the State funds higher education institutions, then notions of academic freedom will always be tempered by the expectation of some sort of reciprocal loyalty.
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Opensource software and localisation in indigenous South African languages with Pootle

- Dalvit, Lorenzo, Terzoli, Alfredo, Wolff, F

  • Authors: Dalvit, Lorenzo , Terzoli, Alfredo , Wolff, F
  • Date: 2008
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/428496 , vital:72515 , https://citeseerx.ist.psu.edu/document?repid=rep1andtype=pdfanddoi=912f3d0d94f0268467e1d790fd7780f14d9c4e44
  • Description: The majority of the South African population is not fully proficient in Eng-lish. Besides access to the necessary infrastructure, many Africans lack epistemological access to the ICT world simply because of linguistic reasons. Limited availability of resources and lack of interest for the promotion of African languages in the ICT domain among their speakers are often blamed for this. The opensource community has been particu-larly responsive to the needs of this portion of the population, and a vari-ety of software is already available in African languages. Translate. org. za, an NGO committed to the development of opensource software in all 11 South African languages, has been particularly active with respect to this. On the one hand, they have developed a Webbased application to support collaborative translation online. On the other, they have part-nered with various institutions to organise translation efforts, mainly rely-ing on volunteers. In this paper we describe an experience showing how these two models can be used to address issues of lack of resources and support for the use of African languages in the ICT domain.
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Optimisation of a sampling protocol for long-term monitoring of temperate reef fishes

- Bennett, Rhett Hamilton

  • Authors: Bennett, Rhett Hamilton
  • Date: 2008
  • Subjects: Marine parks and reserves -- South Africa , Coastal zone management -- South Africa , Fishery management -- South Africa , Reef fishes -- South Africa , Fish communities -- South Africa , Fish stock assessment
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5309 , http://hdl.handle.net/10962/d1005154 , Marine parks and reserves -- South Africa , Coastal zone management -- South Africa , Fishery management -- South Africa , Reef fishes -- South Africa , Fish communities -- South Africa , Fish stock assessment
  • Description: Marine Protected Areas (MPAs), the Ecosystem Approach to Fisheries management (EAF) and Integrated Coastal Management (ICM) have been identified as possible alternatives to traditional linefish management measures, which have largely failed. Monitoring and assessment of fish communities on a long-term basis is necessary, and will provide a means to evaluate the effectiveness of such management measures. Therefore, standardised protocols and optimal sampling methods for long-term monitoring (LTM) and assessment of coastal fish communities are essential. This study aimed to identify suitable methods and develop a protocol for assessment of inshore reef fish communities. A suitable location for evaluation of proposed methods was identified in the warm temperate biogeographical region of South Africa, encompassing the well-established Tsitsikamma Coastal National Park MPA and an adjacent exploited area. Chrysoblephus laticeps (roman) was identified as an indicator species for the study, as it has been well-studied and is well represented in the area. Underwater visual census (UVC) and controlled fishing were identified as suitable methods. UVC transects were found to be superior to point counts, in terms of sampling efficiency, variability, bias and required sample size. An effort of two angler hours per fishing station was shown to provide low catch variability, while at the same time a representative catch and low overall cost and required time. The methods were incorporated in a proposed sampling protocol, and evaluated. The methods were able to detect known differences between protected and exploited communities. It is recommended that LTM within protected areas, for detection of natural change, be focused on community-level indicators, while LTM in exploited areas, aimed at detection of anthropogenic change, be focused on species-level indicators. The proposed protocol with standardised methods will allow for comparisons across a network of LTM sites and provide the opportunity for a broad-scale assessment of the effects of environmental variables on reef fish stocks. The protocol developed in this study has application in other biogeographical regions in South Africa, and other parts of the world. Shift in the focus of much marine research, in South Africa and elsewhere, to LTM, highlights the relevance and timeous nature of this study.
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Optimisation of Bacillus thuringiensis var. israelensis (Vectobac®) applications for the blackfly control programme on the Orange River, South Africa

- Rivers-Moore, Nick A, Bangay, Shaun D, Palmer, R W

  • Authors: Rivers-Moore, Nick A , Bangay, Shaun D , Palmer, R W
  • Date: 2008
  • Language: English
  • Type: Article
  • Identifier: vital:7090 , http://hdl.handle.net/10962/d1012421
  • Description: The Orange River, South Africa's largest river, is a critical water resource for the country. In spite of the clear economic benefits of regulating river flows through a series of impoundments, one of the significant undesirable ecological consequences of this regulation has been the regular outbreaks of the pest blackfly species Simulium chutteri and S. damnosum s.l. (Diptera: Simuliidae). The current control programme, carried out by the South African National Department of Agriculture, uses regular applications, by helicopter, of the target-specific bacterial larvicide Bacillus thuringiensis var. israelensis. While cost-benefit analyses show significant benefits to the control programme, benefits could potentially be further increased through applying smaller volumes of larvicide in an optimised manner, which incorporates upstream residual amounts of pesticide through downstream carry. Using an optimisation technique applied in the West African Onchocerciasis Control Programme, to a 136 km stretch of the Orange River which includes 31 blackfly breeding sites, we demonstrate that 28.5% less larvicide could be used to potentially achieve the same control of blackfly. This translates into potential annual savings of between R540 000 and R1 800 000. A comparison of larvicide volumes estimated using traditional vs. optimised approaches at different discharges, illustrates that the savings on optimisation decline linearly with increasing flow volumes. Larvicide applications at the lowest discharge considered (40 m3·s-1) showed the greatest benefits from optimisations, with benefits remaining but decreasing to a theoretical 30% up to median flows of 100 m3·s-1. Given that almost 70% of flows in July are less than 100 m3·s-1, we suggest that an optimised approach is appropriate for the Orange River Blackfly Control Programme, particularly for flow volumes of less than 100 m3·s-1. We recommend that trials be undertaken over two reaches of the Orange River, one using the traditional approach, and another using the optimised approach, to test the efficacy of using optimised volumes of B.t.i.
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Oxbridge clerics and early ringing in South Africa

- Lewis, Colin A

  • Authors: Lewis, Colin A
  • Date: 2008
  • Language: English
  • Type: Article
  • Identifier: vital:6186 , http://hdl.handle.net/10962/d1012384
  • Description: During the early Twentieth Century, many gifted British clergy came to South Africa. They must have felt optimistic that many rings of bells would soon be installed in their adopted country. South Africa had survived the Boer Wars, the economy was reasonably healthy, new churches were being built and many others were being planned. The Union of South Africa was only a few years old and the political stability of this great part of the British Empire seemed assured. Sadly, their optimism was misplaced and in 2008 only eight rings exist in South Africa. Had it not been for the efforts of the Oxbridge trio: J.R. Vincent, G.H. Ridout and C.E.E. Bulwer, and other British immigrants, however, these rings would not exist. , Colin Lewis was Professor of Geography at Rhodes University, Grahamstown, South Africa from 1989 until his retirement at the end of 2007. In 1990, with the strong support of the incumbent Vice-Chancellor, Dr Derek Henderson, he instigated the Certificate in Change Ringing (Church Bell Ringing) in the Rhodes University Department of Music and Musicology - the first such course to be offered in Africa. Since that date he has lectured in the basic theory, and taught the practice of change ringing. He is the Ringing Master of the Cathedral of St Michael and St George, Grahamstown, South Africa.
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Pan-African multilateralism: transformative or disconnected?

- Bischoff, Paul, 1954-

  • Authors: Bischoff, Paul, 1954-
  • Date: 2008
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/161452 , vital:40628 , https://doi.org/10.1080/02589340802366968
  • Description: Despite a multitude of international institutions on the African continent, worldwide Africa's multilateralism has generally received little attention. Yet, with the emergence of the African Union (AU) and its institutions, questions arise about its character. Will rhetoric and state symbolism take the place of substance or will the space opened up for democracy and civil society participation allow for greater democratically informed sustainability? With this in mind, the article addresses the issue to what extent the character of African multilateralism continues to display features of disconnectedness as opposed to those of transformation, where its institutions address issues of uneven development in concert with civil society concerns.
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Participation, situated culture, and practical reason

- Lotz-Sisitka, Heila, O'Donoghue, Rob B

  • Authors: Lotz-Sisitka, Heila , O'Donoghue, Rob B
  • Date: 2008
  • Subjects: To be catalogued
  • Language: English
  • Type: text , book chapter
  • Identifier: http://hdl.handle.net/10962/437436 , vital:73378 , ISBN 978-1-4020-6415-9 , https://link.springer.com/chapter/10.1007/978-1-4020-6416-6_7
  • Description: This chapter examines the emergence of participatory education as both a central feature and a terrain of ambivalence within the develop-ing landscape of environmental education in South Africa. From its roots in nature experience activities through to more socially critical forms of environmental education, participatory imperatives in this area have yet to address sufficiently the conceptual and practical challenges inherent in pedagogies of participation. We argue that more recent de-velopments reveal similar anomalies, such that participatory education in South Africa has now become an idealised and techniqued logic of practice.
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Perceptions of the gap between theory and practice in the preparation of English language teachers at the Lesotho College of Education

- Molete, Bakae

  • Authors: Molete, Bakae
  • Date: 2008
  • Subjects: Lesotho College of Education Education -- Research -- Lesotho Teachers -- Training of -- Lesotho Student teaching -- Lesotho English language -- Study and teaching -- Lesotho Observation (Educational method) English teachers -- Training of -- Lesotho
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:1936 , http://hdl.handle.net/10962/d1007682
  • Description: The distinction between theory and practice can be traced back to Aristotle (384-322 B.C). Theory has been seen as the preserve of the academician who, through research, produces knowledge for the practitioner to use in his/her practice. This research sets out to investigate perceptions of the respondents with regard to the extent to which theory is applicable in practice. It does this in the context of teacher training at the Lesotho College of Education, (LCE), a teacher training college in Lesotho. In this research project; a case study of 5 students from the LCE who had been on teaching practice, their mentor teachers on teaching practice, and a college lecturer who had observed said students on teaching practice was used. Data was collected by means of focus group interviews and semi-structured interviews. Relevant documents in the form of classroom observation forms were also used. The findings from the data analysis revealed that students on teaching practice had, to a great extent, had difficulties in applying what they had learned at the college when they got to teaching practice. Difficulties were mainly experienced in the areas of classroom and time management as well as in the application of the teaching methods learned at the college. This research takes a closer look at these difficulties. It investigates their probable causes and, finally, suggests ways of responding to them.
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Performance of Mhande song-dance: a contextualized and comparative analysis

- Rutsate, Jerry

  • Authors: Rutsate, Jerry
  • Date: 2008
  • Subjects: Karanga (African people) -- Music Shona (African people) -- Music Folk music -- Zimbabwe Music -- Zimbabwe Folk songs, Shona Mhande Dance music -- Zimbabwe
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:2655 , http://hdl.handle.net/10962/d1002321
  • Description: This thesis is an investigation of the significance of Mhande song-dance in two performance contexts: the Mutoro ritual of the Karanga and the Chibuku Neshamwari Traditional Dance Competition. In addition, I undertake comparative analysis of the structure of Mhande music in relation to the structure of selected genres of Shona indigenous music. The position of Mhande in the larger context of Shona music is determined through analysis of transcriptions of the rhythmic, melodic and harmonic elements of chizambi mouth bow, karimba mbira, ngororombe panpipes, ngano story songs, game, hunting, war, and love songs. Mhande is an indigenous song-dance performed for the mutoro ceremony, the annual rain ritual of the Karanga. The Mhande repertoire consists of distinctive songs and rhythms used for communicating with the majukwa rain spirits. The rain spirits in turn communicate with God (Mwari) the provider of rain, on behalf of the Karanga. Mhande song-dance is performed exactly the same way in the annual Chibuku Neshamwari Traditional Dance Competitions as in the ritual context of the mutoro ceremony. However, in the context of the Competition, it is used for the expression of joy and as a form of cultural identity. The Competition is a forum in which Karanga songdance traditions such as Mhande, compete with other Shona song-dance traditions such as mbakumba, shangara and chinyambera. I contextualize and analyse Mhande song-dance by using the ‘Matonjeni Model’, which in terms of Karanga epistemology, is culture specific. This Model is grounded in description, interpretation and analysis; the primary methods in my research process.
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Phosphorescence of orthopaedic–grade ultra high molecular weight polyethylene

- Chithambo, Makaiko L

  • Authors: Chithambo, Makaiko L
  • Date: 2008
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/125617 , vital:35801 , https://doi.10.1002/pssc.200776802
  • Description: Isothermal luminescence decay curves have been measured from orthopaedic–standard ultra high molecular weight polyethylene between 35 and 70 ˚C on the rising edge of the main glow peak at 70 ˚C. Preparatory peak-shape analysis of the temperature-resolved glow peak at 70 ˚C measured at 1 ˚C s–1 gave a geometrical factor close to 0.5 suggestive of second order kinetics for both the isothermal and thermally stimulated luminescence. The results of analysis of the phosphorescence of transformed monotonic-to-peak isothermal decay curves are also second order, as is the conclusion from thermoluminescence glow-curve de-convolution. All methods of analysis give an activation energy of about 0.7 eV.
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Photocatalytic oxidation of 1-hexene using GaPc and InPc octasubstituted derivatives

- Chauke, Vongani, Nyokong, Tebello

  • Authors: Chauke, Vongani , Nyokong, Tebello
  • Date: 2008
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/268611 , vital:54214 , xlink:href="https://doi.org/10.1016/j.molcata.2008.04.003"
  • Description: Photocatalytic oxidation of 1-hexene by GaPc (1a–1c) and InPc (2a–2c) derivatives (Pc = phthalocyanine) is hereby presented. The derivatives studied are Pc octasubstituted with phenoxy (a), 4-tert-butylphenoxy (b) or benzyloxyphenoxy (c) at the peripheral positions. The photocatalytic oxidation products for 1-hexene were 1,2-epoxyhexane and 1-hexen-3-ol. The %conversion values of 1-hexene and %selectivity of 1,2-epoxyhexane were generally higher for InPc derivatives. Even though InPc derivatives showed better photocatalytic results than GaPc derivatives, the former were less stable relative to the latter. Both type I and type II mechanism were implicated in the photocatalysis mechanism.
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Photocatalytic transformation of 4-nitrophenol in aqueous media using suspended, water-insoluble metallophthalocyanine complexes

- Marais, Eloïse A, Antunes, Edith M, Nyokong, Tebello

  • Authors: Marais, Eloïse A , Antunes, Edith M , Nyokong, Tebello
  • Date: 2008
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/265986 , vital:53907 , xlink:href="https://doi.org/10.1080/00958970802146056"
  • Description: Unsubstituted magnesium (MgPc), zinc (ZnPc) and chloroaluminium (ClAlPc) phthalocyanine complexes and the ring substituted zinc tetranitro (ZnPc(NO2)4), zinc tetraamino (ZnPc(NH2)4), zinc hexadecafluoro (ZnPcF16) and zinc hexadecachloro (ZnPcCl16), phthalocyanine complexes are employed as photocatalysts for the heterogeneous transformation of 4-nitrophenol (4-Np) to fumaric acid and 4-nitrocatechol. ClAlPc is the best catalyst, with 89 ± 8% degradation of 4-Np after 100 min. The least effective catalysts were ZnPcCl16 and MgPc.
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Photoinduced energy transfer between water-soluble CdTe quantum dots and aluminium tetrasulfonated phthalocyanine

- Idowu, Mopelola, Chen, Ji-Yao, Nyokong, Tebello

  • Authors: Idowu, Mopelola , Chen, Ji-Yao , Nyokong, Tebello
  • Date: 2008
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/268564 , vital:54210 , xlink:href="https://doi.org/10.1039/B707808K"
  • Description: Thiol stabilized CdTe quantum dots (QDs) synthesized in aqueous phase were used as energy donors to aluminium tetrasulfonated phthalocyanine (AlTSPc) through fluorescence resonance energy transfer (FRET). Energy transfer occurred from the QDs to AlTSPc upon photoexcitation of the QDs. An enhancement in efficiency of energy transfer with the nature of the carboxylic thiol stabilizers on the QDs was observed. The results showed that for enhanced FRET to occur, the donor–acceptor distance has to be lower than the critical distance. The quenching constant K as well as the binding constant kb values were calculated suggesting strong interaction of the QDs with the AlTSPc. Study of the photophysics of AlTSPc in the presence of the QDs revealed a high triplet state yield, hence the possibility of using QDs in combination with phthalocyanines as photosensitizers in photodynamic therapy. The triplet state lifetimes of AlTSPc in the presence of the QDs were calculated and the lifetime in the presence of CdTe capped with 3-mercaptopropionic acid (MPA) was found to be the longest. MPA capped QD in a mixture with AlTSPc resulted in long triplet lifetime and high triplet yield of the latter, and high energy transfer efficiency, hence was found to be most suitable as a potential candidate for photodynamic therapy of cancer studies.
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Photophysical and photochemical properties of tetrasulfonated silicon and germanium phthalocyanine in aqueous and non-aqueous media

- Idowu, Mopolela, Nyokong, Tebello

  • Authors: Idowu, Mopolela , Nyokong, Tebello
  • Date: 2008
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/268624 , vital:54215 , xlink:href="https://doi.org/10.1016/j.jphotochem.2008.01.004"
  • Description: The photophysical and photochemical properties of tetrasulfonated silicon and germanium phthalocyanine (SiPcS4 and GePcS4) in aqueous solution (phosphate-buffered saline (PBS) solution, pH 7.4) (in the presence and absence of cremophore EL (CEL)) and in dimethylsulphoxide (DMSO) were studied. The complexes have intense absorption in the visible/near-IR region though they highly aggregate in aqueous solution with a dimerization constant of ∼2 × 104 dm3 mol−1. The fluorescence excitation spectra however have only one band suggesting that only the monomer fluoresces. Both the quantum yields of the triplet state (ΦT) and the triplet lifetimes (τT) were found to be higher in DMSO compared to in aqueous solution. Aggregation is hindered by addition of cremophore EL in aqueous solution and this induced disaggregation caused an increased ΦT and τT probably due to the reduced interaction of the phthalocyanines with the aqueous medium in the presence of CEL.
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