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Applications of lead phthalocyanines embedded in electrospun fibers for the photoinactivation of Escherichia coli in water

  • Authors: Osifeko, Olawale L , Nyokong, Tebello
  • Date: 2014
  • Language: English
  • Type: Article
  • Identifier: vital:7304 , http://hdl.handle.net/10962/d1020381
  • Description: Lead (II) pyridyloxyphthalocyanine (PbTpyPc) and its quaternized form (PbTepyPc) were synthesized and the photophysical behavior examined. Low fluorescence quantum yields (ΦF) of 0.01 and 0.02 were observed for PbTepyPc and PbTpyPc, respectively. The singlet oxygen quantum yields (ΦΔ) were 0.60 and 0.68, for PbTepyPc and PbTpyPc, respectively using DPBF as a quencher in DMF. Singlet oxygen production of the embedded sensitizers in electrospun fiber were quantified using ADMA and were found to be ΦΔ = 0.41 and ΦΔ = 0.21 for PbTepyPc and PbTpyPc, respectively. Photodynamic inactivation of Escherichia coli (E. coli) with the quaternized photosensitizer at 5 μM, totally inactivated the E. coli (with log CFU = 10 decrease). Only 0.4 log CFU decrease was obtained with PbTpyPc. The embedded non-quaternized photosensitizer (PbTpyPc) was less active on the gram negative bacteria but the quaternized photosensitizer (PbTepyPc) was effective towards inactivation of E. coli. , Original publication is available at http://dx.doi.org/10.1016/j.dyepig.2014.05.010
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  • Date Issued: 2014

Behavior of Palladium Nanoparticles in the Absence or Presence of Cobalt Tetraaminophthalocyanine for the Electrooxidation of Hydrazine

  • Authors: Maringa, Audacity , Nyokong, Tebello
  • Date: 2014
  • Language: English
  • Type: Article
  • Identifier: vital:7305 , http://hdl.handle.net/10962/d1020382
  • Description: We report on the electrodeposition of palladium nanoparticles (PdNPs) on a glassy carbon electrode (GCE) and onto a poly-CoTAPc-GCE (CoTAPc=cobalt tetraamino phthalocyanine) surface. The electrodes are denoted as PdNPs-GCE and PdNPs/poly-CoTAPc-GCE, respectively. PdNPs/poly-CoTAPc-GCE showed the best activity for the oxidation of hydrazine at the lowest potential of −0.28 V and with the highest currents. The results were further supported by electrochemical impedance spectroscopy (EIS) which showed that there was less resistance to charge transfer for PdNPs/poly-CoTAPc-GCE compared to PdNPs-GCE. The catalytic rate constant for hydrazine oxidation was 6.12×108 cm3 mol−1 s−1 using PdNPs/poly-CoTAPc-GCE. , Original publication is available at http://dx.doi.org/10.1002/elan.201400028
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  • Date Issued: 2014

Bells as memorials in South Africa to the Great (1914-18) War

  • Authors: Lewis, Colin A , De Wet, Tertius , Teugels, Jet L , Van Deventer, Pieta J U
  • Date: 2014
  • Language: English
  • Type: Article , text
  • Identifier: vital:6192 , http://hdl.handle.net/10962/d1013418
  • Description: The contribution of South Africa to the allied cause in the Great War, and the sacrifice of so many lives of the White and Coloured populations, is memorialised on bells of the Cape Town carillon, on ringing, and on clock and other bells. The contribution of the Black population awaits recognition. Restoration of the Cape Town carillon so that it can again be played effectively, would be a fitting memorial to those who lost their lives in the non-combative roles that were open to the majority population of South Africa. Completion of the ring at what is now Queenstown cathedral would also be a fitting tribute to the bravery and unstinting service of so many South Africans during the Great War. , 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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  • Date Issued: 2014

Cracks in reproductive health rights: knowledge of abortion legislation stipulations amongst learners in Buffalo City, South Africa

  • Authors: Macleod, Catriona I , Seutlwadi, Lebogang , Steele, Gary I
  • Date: 2014
  • Language: English
  • Type: Article
  • Identifier: vital:6296 , http://hdl.handle.net/10962/d1014772
  • Description: Background: The Choice on Termination of Pregnancy (CTOP) Act legalised abortion on request in South Africa until up to 12 weeks of gestation and thereafter under specified conditions. Within the context of liberal legislation, accurate information is a necessary (although not sufficient) requirement for women to exercise their reproductive rights. Objectives: This research investigated Grade 11 learners’ knowledge of the CTOP Act and its stipulations. Methods: Survey research was conducted with respondents drawn from a range of schools in Buffalo City, South Africa. Multi-stage sampling was used, namely stratified random sampling of schools and purposive sampling of grades used within schools. The data were collected by means of self-administered questionnaires in group situations. Results: Results indicate that knowledge of the legal status of abortion, as well as of the various stipulations of the law, was poor. Various misunderstandings were evident, including that spousal approval is required in order for married women to have an abortion. Significant differences between the knowledge of respondents at the various schools were found, with those learners attending schools formerly designated for African learners during Apartheid having the least knowledge. Conclusion: Given the multiple factors that may serve as barriers to women accessing abortion, it is imperative that at least the most fundamental aspect of reproductive rights, that is, the right to information, is not undermined.
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  • Date Issued: 2014

Effects of pyrene on the photophysical and two-photon absorption-based nonlinear optical properties of indium(III) phthalocyanines

  • Authors: Sanusi, Kayode , Nyokong, Tebello
  • Date: 2014
  • Language: English
  • Type: Article
  • Identifier: vital:7314 , http://hdl.handle.net/10962/d1020540
  • Description: Photophysical and two-photon-dependent nonlinear absorption properties of two chloroindium(III) phthalocyanines bearing pyrene units have been investigated. The tetra- (3) and the tri- (4) pyrene-substituted phthalocyanines exhibit strong triplet absorption with high triplet yields () of 0.79 and 0.83, respectively. The measured nonlinear optical data, such as the two photon absorption cross-sections, the third- and second-order nonlinearities were found to be comparable with those of literature, thus, making the compounds promising candidates for a broad range of nonlinear optical applications. , Original publication is available at http://dx.doi.org/10.1080/00958972.2014.959509
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  • Date Issued: 2014

New possibilities for research on reef fish across the continental shelf of South Africa

  • Authors: Bernard, Anthony T F , Gotz, A , Parker, Daniel M , Heyns, Elodie R , Halse, S J , Riddin, N A , Smith, M K S , Paterson, Angus W , Winker, A Henning , Fullwood, L , Langlois, T J , Harvey, E S
  • Date: 2014
  • Language: English
  • Type: Article
  • Identifier: vital:6971 , http://hdl.handle.net/10962/d1014566
  • Description: [From introduction] Subtidal research presents numerous challenges that restrict the ability to answer fundamental ecological questions related to reef systems. These challenges are closely associated with traditional monitoring methods and include depth restrictions (e.g. safe diving depths for underwater visual census), habitat destruction (e.g. trawling), mortality of target species (e.g. controlled angling and fish traps), and high operating costs (e.g. remotely operated vehicles and large research vessels. Whereas many of these challenges do not apply or are avoidable in the shallow subtidal environment, the difficulties grow as one attempts to sample deeper benthic habitats. This situation has resulted in a paucity of knowledge on the structure and ecology of deep water reef habitats around the coast of South Africa and in most marine areas around the world. Furthermore, the inability to effectively survey deep water benthic environments has limited the capacity of researchers to investigate connectivity between shallow and deep water habitats in a standardised and comparable fashion.
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  • Date Issued: 2014

Outside city limits: introducing Anton van der Merwe of Starways Arts, in Hogsback, Eastern Cape, South Africa

  • Authors: Steele, John
  • Date: 2014
  • Language: English
  • Type: text , Article
  • Identifier: http://hdl.handle.net/11260/1012 , vital:30191
  • Description: Certain contemporary artists in South Africa choose to live in rural areas rather than in cities. This paper explores some reasons for this preference, and also looks at countercultural back-to-the-earth trends and other factors that may have encouraged some of these artists to prefer to live and work in rural settings. It is against this background that artist Anton van der Merwe is introduced and his early choices of spaces in which to work, both as a potter and painter, are examined. This background serves to contextualise his decision, made in 1992, to move home and studio from Midrand in Gauteng to Hogsback village, in rural Eastern Cape. Hardships were faced, artistic growth has been experienced, and a flourishing visual arts practice has been established by him at Starways Arts. In conclusion, it is noted that involvement in aspects of local community affairs have resulted in widespread mutual benefit.
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  • Date Issued: 2014

Photophysical behavior of Zn aminophenoxy substituted phthalocyanine conjugates with carboxylic acid-coated silica nanoparticles: Effect of point of substitution

  • Authors: Fashina, Adedayo , Antunes, Edith M , Nyokong, Tebello
  • Date: 2014
  • Language: English
  • Type: Article
  • Identifier: vital:7318 , http://hdl.handle.net/10962/d1020563 , Original publication is available at http://dx.doi.org/10.1016/j.molstruc.2014.04.034
  • Description: This work reports on the grafting of silica nanoparticles with zinc phthalocyanine complexes tetra-substituted non-peripherally and peripherally with a 4-amino phenoxy group. The phthalocyanine dyes have free amino groups, facilitating covalent attachment of the dyes on the silica surface via amide bond formation. The surface area of the functionalized silica nanoparticles increased on conjugation but the pore volumes were reduced. The phthalocyanine functionalized silica nanoparticles showed lower fluorescence quantum yields as well as shorter triplet lifetimes compared to the free phthalocyanines in dimethyl formamide. For the non-peripherally substituted phthalocyanines increases in triplet yield quantum yields, lifetimes, and singlet oxygen quantum yields were observed.
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  • Date Issued: 2014

Sailing between Scylla and Charybdis: Mayelane v Ngwenyama

  • Authors: Kruuse, Helen
  • Date: 2014
  • Language: English
  • Type: Article , text
  • Identifier: http://hdl.handle.net/10962/54118 , vital:26392 , https://www.ajol.info/index.php/pelj/article/view/112096
  • Description: Mayelane v Ngwenyama 2013 4 SA 415 (CC) is arguably the most important judgment concerning the recognition of customary marriages in recent times. This article attempts to unpack some of the many issues that arise from the case, namely: (a) the practical difficulties associated with ascertaining living customary law and the problems of identifying legal versus social norms; (b) the meaning of consent as a requirement of a customary marriage; (c) the implications of the case for equality between multiple wives in a customary marriage, and as between wives across customary marriages of different cultural traditions; and (e) the implications of the case for equality considerations more broadly. While the authors sympathise with the court in respect of the complex decision before it, it questions the Court's method and result, specifically for the equality rights of a second (or further) "wife" in a Vatsonga customary marriage. The authors suggest that the issues should be put to democratic deliberation by the legislative arm, rather than leaving courts in the unenviable position of having to decide these matters.
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  • Date Issued: 2014

Some reflections on two rural potter's cooperatives in the Port St Johns region of the Eastern Cape, South Africa

  • Authors: Steele, John
  • Date: 2014
  • Language: English
  • Type: text , Article
  • Identifier: http://hdl.handle.net/11260/1001 , vital:30181
  • Description: Two potters in the Port St Johns region of the Eastern Cape province of South Africa have been founder members of different visual arts producer’s cooperatives during the 1980s as part of development initiatives aimed at sustainable economic empowerment. These potters are Debora Nomathamsanqa Ntloya of Qhaka village in the Caguba area and Alice Gqa Nongebeza of Nkonxeni village in the Tombo area. They both engaged in zero electricity, using ceramics praxis and used variants of open bonfiring techniques to finish off their works. This article looks at aspects of formation and administration of such potter’s cooperatives, as well as at types of ceramics technology used and resulting works, and also at some marketing strategies and outcomes. It will be seen that these are factors that impact directly on why some such cooperatives are successful for long stretches of time, and others become defunct or dormant. Furthermore, Debora Nomathamsanqa Ntloya is now largely retired from clayworking, and Alice Gqa Nongebeza passed away in 2012, so a question arises as to whether their ceramic traditions will be continued in the years to come.
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  • Date Issued: 2014

Starways Arts: a built environment expressing holistic lifestyles dedicated to visual and performing arts in Hogsback, Eastern Cape, South Africa

  • Authors: Steele, John
  • Date: 2014
  • Language: English
  • Type: text , Article
  • Identifier: http://hdl.handle.net/11260/990 , vital:30179
  • Description: In 1992, Anton van der Merwe and his life partner Gwyneth Lloyd moved from Randjesfontein Pottery in Midrand, between Johannesburg and Pretoria, to an undeveloped smallholding in the densely forested rural village of Hogsback. The past 22 years have seen an ongoing process of settling down and construction of necessary buildings. This paper seeks to explore aspects of philosophical and architectural influences that served as some of the foundation stones for creation of an eclectic series of buildings, including their home, visual arts studios, a gallery, a community theatre and guest accommodation. A review of these buildings will show that Van der Merwe and Lloyd have developed an idiosyncratic construction style that incorporates alternative technology with empathetic use of natural resources, which results in organically flowing living and working spaces that are fit for purpose, have substantial presence and have minimal environmental impact.
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  • 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.
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  • Date Issued: 2014

Tufa stromatolite ecosystems on the South African south coast

  • Authors: Perissonotto, Renzo , Bornman, Tommy G , Steyn, Paul-Pierre , Miranda, Nelson A F , Dorrington, Rosemary A , Matcher, Gwynneth F , Strydom, Nadine A , Peer, Nasreen
  • Date: 2014
  • Language: English
  • Type: Article
  • Identifier: vital:6490 , http://hdl.handle.net/10962/d1014585 , http://dx.doi.org/10.1590/sajs.2014/20140011
  • Description: Following the first description of living marine stromatolites along the South African east coast, new investigations along the south coast have revealed the occurrence of extensive fields of actively calcifying stromatolites. These stromatolites have been recorded at regular distances along a 200-km stretch of coastline, from Cape Recife in the east to the Storms River mouth in the west, with the highest density found between Schoenmakerskop and the Maitland River mouth. All active stromatolites are associated with freshwater seepage streams flowing from the dune cordon, which form rimstone dams and other accretions capable of retaining water in the supratidal platform. Resulting pools can reach a maximum depth of about 1 m and constitute a unique ecosystem in which freshwater and marine organisms alternate their dominance in response to vertical mixing and the balance between freshwater versus marine inflow. Although the factors controlling stromatolite growth are yet to be determined, nitrogen appears to be supplied mainly via the dune seeps. The epibenthic algal community within stromatolite pools is generally co-dominated by cyanobacteria and chlorophytes, with minimal diatom contribution.
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  • Date Issued: 2014

The Educational Journal

  • Date: 2013-12
  • Subjects: Education – South Africa , South Africa – Economic conditions , South Africa – Social conditions
  • Language: English
  • Type: text , Article
  • Identifier: http://hdl.handle.net/10948/38349 , vital:34591 , Bulk File 7
  • Description: The Educational Journal was the official organ of the Teachers' League of South Africa and focussed on education within the context of a racialized South Africa. From the 2000s, the journal was published by the National Union of Public Service and Allied Workers (NUPSAW), a trade union formed in August 1998 from the amalgamation of militant and moderate trade unions and also operated in the education sphere.
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  • Date Issued: 2013-12

The Educational Journal

  • Date: 2013-07
  • Subjects: Education – South Africa , South Africa – Economic conditions , South Africa – Social conditions
  • Language: English
  • Type: text , Article
  • Identifier: http://hdl.handle.net/10948/38379 , vital:34739 , Bulk File 7
  • Description: The Educational Journal was the official organ of the Teachers' League of South Africa and focussed on education within the context of a racialized South Africa. From the 2000s, the journal was published by the National Union of Public Service and Allied Workers (NUPSAW), a trade union formed in August 1998 from the amalgamation of militant and moderate trade unions and also operated in the education sphere.
  • Full Text: false
  • Date Issued: 2013-07

The Educational Journal

  • Date: 2013-03
  • Subjects: Education – South Africa , South Africa – Economic conditions , South Africa – Social conditions
  • Language: English
  • Type: text , Article
  • Identifier: http://hdl.handle.net/10948/38619 , vital:34840 , Bulk File 7
  • Description: The Educational Journal was the official organ of the Teachers' League of South Africa and focussed on education within the context of a racialized South Africa. From the 2000s, the journal was published by the National Union of Public Service and Allied Workers (NUPSAW), a trade union formed in August 1998 from the amalgamation of militant and moderate trade unions and also operated in the education sphere.
  • Full Text: false
  • Date Issued: 2013-03

First results on bathymetry, stratification and physicochemical limnology of a small tropical African reservoir (Malilangwe, Zimbabwe)

  • Authors: Dalu, Tatena , Thackeray, Zane , Leuci, Rio , Clegg, Bruce , Chari, Lenin D , Nhiwatiwa, Tamuka
  • Date: 2013-01-11
  • Language: English
  • Type: Article
  • Identifier: vital:6970 , http://hdl.handle.net/10962/d1013297
  • Description: The study provides a 9-month record of Malilangwe Reservoir water chemistry periodicity, for the period between February and October 2011. Malilangwe Reservoir is a small (211 ha), shallow (mean depth 4.54 m) reservoir situated in the south-eastern lowveld of Zimbabwe. The reservoir has not spilled in nearly 11 years, which makes it a unique system as most reservoirs of comparable size spill annually. This is the first bathymetric and limnological study of the reservoir where the morphology and physicochemical quality of the water body were examined. The reservoir was not strongly stratified during the hot-wet and hot-dry season with oxygen depletion of < 2 mg·ℓ-1 DO being observed in the bottom layers (<6 m depth). Nutrient concentrations varied throughout the seasons. The reservoir exhibited marked seasonal fluctuations in water level, which decreased by over 149 cm between February and October. The N:P ratio rose to as high as 10.9 and generally reflected high levels of phosphorus in the reservoir. There were significant differences (p<0.05) in Secchi depth transparency between the study sites. Differences observed in water quality were due to water level fluctuations, with poor water quality conditions being experienced during the hot-dry season and the cool-dry season when water levels were low. The reservoir was classified as being mesotrophic. Therefore, there is a risk of eutrophication, especially since the reservoir is currently merely a sink for nutrients.
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A performative-performance analytical approach: infusing Butlerian theory into the narrative-discursive method

  • Authors: Morison, Tracy , Macleod, Catriona I
  • Date: 2013
  • Language: English
  • Type: Article
  • Identifier: vital:6212 , http://hdl.handle.net/10962/d1003065 , http://dx.doi.org/10.1177/1077800413494344
  • Description: Judith Butler’s theory of performativity provides gender theorists with a rich theoretical language for thinking about gender. Despite this, Butlerian theory is difficult to apply, as Butler does not provide guidance on actual analysis of language use in context. In order to address this limitation, we suggest carefully supplementing performativity with the notion of performance in a manner that allows for the inclusion of relational specificities and the mechanisms through which gender, and gender trouble, occur. To do this, we turn to current developments within discursive psychology and narrative theory. We extend the narrative-discursive method proposed by Taylor and colleagues, infusing it with Butlerian theory in order to fashion a dual analytical lens, which we call the performativity-performance approach. We provide a brief example of how the proposed analytical process may be implemented.
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  • Date Issued: 2013

A tale of two neglected systems-structure and function of the thin- and thick-walled sieve tubes in monocotyledonous leaves

  • Authors: Botha, Christiaan E J
  • Date: 2013
  • Language: English
  • Type: Article , text
  • Identifier: vital:6499 , http://hdl.handle.net/10962/d1004514 , http://dx.doi.org/10.3389/fpls.2013.00297
  • Description: There is a large body of information relating to the ontogeny, development and the vasculature of eudicotyledonous leaves. However, there is less information available concerning the vascular anatomy of monocotyledonous leaves. This is surprising, given that there are two uniquely different phloem systems present in large groups such as grasses and sedges. Monocotyledonous leaves contain marginal, large, intermediate, and small longitudinal veins that are interconnected by numerous transverse veins. The longitudinal veins contain two metaphloem sieve tube types, which, based upon their ontogeny and position within the phloem, are termed early (thin-walled) and late (thick-walled) sieve tubes. Early metaphloem comprises sieve tubes, companion cells and vascular parenchyma (VP) cells, whilst the late metaphloem, contains thick-walled sieve tubes (TSTs) that lack companion cells. TSTs are generally adjacent to, or no more than one cell removed from the metaxylem. Unlike thin-walled sieve tube (ST) -companion cell complexes, TSTs are connected to parenchyma by pore-plasmodesma units and are generally symplasmically isolated from the STs. This paper addresses key structural and functional differences between thin- and thick-walled sieve tubes and explores the unique advantages of alternate transport strategies that this 5–7 million years old dual system may offer. It would seem that these two systems may enhance, add to, or play a significant role in increasing the efficiency of solute retrieval as well as of assimilate transfer.
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  • Date Issued: 2013

Anniversary Bulletin 1943-2013: 70 Years of Struggle... and the Struggle Continues

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