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Development and validation of an In Vitro Release Test (IVRT) to investigate the release of miconazole nitrate from topical cream formulations

- Purazi, Potiwa

  • Authors: Purazi, Potiwa
  • Date: 2017
  • Language: English
  • Type: text , Thesis , Masters , MSc
  • Identifier: http://hdl.handle.net/10962/65223 , vital:28711
  • Description: Expected release date-May 2019
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  • Date Issued: 2017

Development of an item bank of health literacy questions appropriate for limited literacy public sector patients in South Africa:

- Marimwe, Chipiwa, Dowse, Roslind

  • Authors: Marimwe, Chipiwa , Dowse, Roslind
  • Date: 2017
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/156618 , vital:40031 , https://doi.org/10.1080/17538068.2017.1380577
  • Description: The majority of current health literacy measures emanate from high-income countries. In South Africa, there is no appropriate measure available for use by the diverse public sector population, many of whom have some literacy limitations. The objective was to develop a bank of questions for this population informed by a broader definition of health literacy, which acknowledges both traditional cognitive skills and explores the influence of the collective social environment on health literacy. Thirty questions for the Item Bank were developed to ensure cultural, contextual and educational appropriateness, and were continuously subjected to critical review by an expert consultant panel. Patients (n = 120) were recruited from a local primary care clinic and individually interviewed with the assistance of an interpreter to collect data on the Item Bank, Multidimensional Screener of Functional Health Literacy (MSFHL) and sociodemographics.
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  • Date Issued: 2017

Development of Bioinformatics Infrastructure for Genomics Research:

- Mulder, Nicola J, Adebiyi, Ezekiel, Adebiyi, Marion, Adeyemi, Seun, Ahmed, Azza, Ahmed, Rehab, Akanle, Bola, Alibi, Mohamed, Armstrong, Don L, Aron, Shaun, Ashano, Efejiro, Baichoo, Shakuntala, Benkahla, Alia, Brown, David K, Chimusa, Emile Rugamika, Fadlelmola, Faisal M, Falola, Dare, Fatumo, Segun, Ghedira, Kais, Ghouila, Amel, Hazelhurst, Scott, Itunuoluwa Isewon, Segun Jung, Kassim, Samar Kamal, Kayondo, Jonathan K, Mbiyavanga, Mamana, Meintjes, Ayton, Mohammed, Somia, Mosaku, Abayomi, Moussa, Ahmed, Muhammd, Mustafa, Mungloo-Dilmohamud, Zahra, Nashiru, Oyekanmi, Odia, Trust, Okafor, Adaobi, Oladipo, Olaleye, Osamor, Victor, Oyelade, Jellili, Sadki, Khalid, Salifu, Samson Pandam, Soyemi, Jumoke, Panji, Sumir, Radouani, Fouzia, Souiai, Oussama, Tastan Bishop, Özlem

Differentiations and intersections: a corpus-assisted discourse study of gender representations in the British press before, during and after the London Olympics 2012

- Jaworska, Sylvia, Hunt, Sally

  • Authors: Jaworska, Sylvia , Hunt, Sally
  • Date: 2017
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/139205 , vital:37714 , DOI 10.1558/genl.28858
  • Description: This study examines the impact of a global sports event on gender representations in media reporting. Whereas previous research on gender, sport and media has been mainly concerned with sports events in the North American or Australian context, this study investigates the British media reporting before, during and after the London Olympics 2012. Our study follows the approach of Corpus-Assisted Discourse Studies (CADS) and uses both quantitative and qualitative research procedures. The results reveal more balanced gender representations during the London Olympics in that the ‘regular’ biased associations were supressed in favour of positive references to female achievements. However, little carry-though of the ‘gains’ was noted. Also, this study shows that the positive associations intersected with national sentiments and were used to celebrate the nation-state. At the same time, some subtle resistance was observed to accepting as ‘truly’ British the non-white athletes and those not born in Britain.
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  • Date Issued: 2017

Disclaiming/denigrating/dodging: white South African academics’ everyday racetalk

- Vincent, Louise, Idahosa, Grace E, Msomi, Zuziwe

  • Authors: Vincent, Louise , Idahosa, Grace E , Msomi, Zuziwe
  • Date: 2017
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/141900 , vital:38014 , DOI: 10.1080/14725843.2017.1292119
  • Description: The call for the ‘transformation’ of higher education in South Africa is one instance of a wider effort, since the country’s first democratic election in 1994, to surmount an apartheid and colonial legacy of institutionalised racism. In 2015 and 2016 nationwide protests led to universities being shut down as students and staff expressed frustration institutions that continue to be experienced as racist and ‘untransformed’. In this study we report on interviews conducted with senior white academics at one South African university shortly before these protests began. Given that our participants are people of influence in their respective university departments, we asked, in in-depth open-ended interviews, what contribution they saw themselves making to ‘transformation’. We argue that the talk of these participants could be described as what authors in the field call 'racetalk', Talk is understood here as a form of social practice, the analysis of which helps us to understand how racism is reproduced in mundane ways which, taken together, account for the persistence of pervasive institutionalised racism in South African higher education that appears impervious to policy and regime change.
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  • Date Issued: 2017

Distributed leadership in South Africa

- Grant, Carolyn

  • Authors: Grant, Carolyn
  • Date: 2017
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/281024 , vital:55684 , xlink:href="https://doi.org/10.1080/13632434.2017.1360856"
  • Description: Distributed leadership, while an established concept in the international literature on education leadership, is slowly gaining prominence in post-apartheid South Africa. This is primarily due to its normative and representational appeal. However, of concern is that the concept has become a catch-all phrase to describe any form of devolved or shared leadership and is being espoused as ‘the answer’ to the country’s educational leadership woes. Drawing on a South African publications-based doctoral study of distributed teacher leadership (Grant 2010. “Distributed Teacher Leadership: Troubling the Terrain.” Unpublished PhD diss., University of KwaZulu-Natal, Pietermaritzburg) for its evidence, this article argues for a theoretically robust form of distributed leadership conceptualised as socio-cultural practice and framed as a product of the joint interactions of school leaders, followers and aspects of their situation (Gronn 2000. “Distributed Properties: A New Architecture for Leadership.” Educational Management and Administration 28 (3): 317–338; Spillane, Halverson and Diamond 2004. “Towards a Theory of Leadership Practice: A Distributed Perspective.” Journal of Curriculum Studies 36 (1): 3–34; Spillane 2006. Distributed Leadership. San Francisco: Jossey-Bass). It endorses a sequential distributed leadership framing for the South African context and calls for further empirical studies which interrogate the complex practices of distributed school leadership. For without this theoretically robust work, the article argues, distributed leadership is likely to be relegated to the large pile of redundant leadership theories and become a passing fad.
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  • Date Issued: 2017

Do microplastic loads reflect the population demographics along the southern African coastline?

- Nel, Holly A, Hean, Jeffrey W, Noundou, Xavier S, Froneman, P William

  • Authors: Nel, Holly A , Hean, Jeffrey W , Noundou, Xavier S , Froneman, P William
  • Date: 2017
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/67961 , vital:29174 , https://doi.org/10.1016/j.marpolbul.2016.11.056
  • Description: Publisher version , Plastic pollution is a major anthropogenic contaminant effecting the marine environment and is often associated with high human population densities and industrial activities. The microplastic (63 to 5000 μm) burden of beach sediment and surf-zone water was investigated at selected sites along the entire length of the South African coastline. It was predicted that samples collected in areas of high population density, would contain a higher microplastic burden than those along coasts that demonstrate very low population densities. With the exception of water column microplastics within Richard's Bay Harbour (413.3 ± 77.53 particles·m− 3) and Durban Harbour (1200 ± 133.2 particles·m− 3), there were no significant spatial differences in microplastic loads. This supports the theory that harbours act as a source of microplastics for the surrounding marine environment. Additionally, the absence of any spatial variation highlights the possible long range distribution of microplastic pollutants by large scale ocean currents.
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  • Date Issued: 2017

Dose response and kinetic analysis of thermoluminescence of Li–Zn fluoroborate glass

- Thomas, Sunil, Chithambo, Makaiko L

  • Authors: Thomas, Sunil , Chithambo, Makaiko L
  • Date: 2017
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/116164 , vital:34326 , https://doi.org/10.1080/10420150.2017.1313844
  • Description: The intention of this study is to explore the thermoluminescence properties of beta-irradiated Li–Zn fluoroborate glass. The glow-curve corresponding to 10 Gy shows two peaks when measured at 1°C/s. The dose response of the glass to beta irradiation was investigated. The trapping level parameters such as activation energy, frequency factor and order of kinetics associated with the observed glow-peak were determined using different methods. The thermoluminescence is affected by thermal quenching. A possible mechanism for the thermoluminescence is described.
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  • Date Issued: 2017

Ecosystem-scale impacts of non-timber forest product harvesting: Effects on soil nutrients

- Ruwanza, Sheunesu, Shackleton, Charlie M

  • Authors: Ruwanza, Sheunesu , Shackleton, Charlie M
  • Date: 2017
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/180099 , vital:43309 , xlink:href="https://doi.org/10.1111/1365-2664.12891"
  • Description: The harvesting of non-timber forest products (NTFPs) is a global phenomenon, the sustainability of which has been studied for many species at the individual and population level. However, the broader scale impacts of NTFP harvesting have been acknowledged but rarely examined. We assessed plant size and the soil attributes undercanopy and in the open, in replicate, paired harvested and non-harvested sites for three NTFPs differing in the extent of biomass removed, i.e. timber for firewood from a tree (Acacia karroo), fruits from a cactus (Opunita ficus-indica) and flowering culms from a grass (Cymbopogon marginatus). Soil variables tested included pH, resistivity, P, total N, nitrate nitrogen, ammonium nitrogen, K, Na, Ca and Mg. The extent of loss of soil nutrients decreased across the three NTFPs relative to the proportion of biomass removed. Thus, significant differences in more soil variables were evident for the firewood species, least for the fruit species and intermediate for the grass species. Lower soil pH, P, C and K were evident in soils collected underneath A. karroo, while losses in cations of Na, Ca and Mg were reported in soils underneath C. marginatus, and only NO3N losses were recorded underneath O. ficus-indica. Our study reveals that while non-timber forest product (NTFP) harvesting may affect soil nutrients, this is not uniform between species and is likely to be a function of the extent of biomass removed and harvesting frequency. This indicates the need for caution in generalisations about the ecosystem-level impacts of NTFP harvesting as well as a concerted effort to better understand impacts at a greater range of scales than has been the case to date.
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  • Date Issued: 2017

Education and the common good

- Lotz-Sisitka, Heila

  • Authors: Lotz-Sisitka, Heila
  • Date: 2017
  • Language: English
  • Type: text , book chapter
  • Identifier: http://hdl.handle.net/10962/126060 , vital:35846 , ISBN 9783319513225 , https://link.springer.com/chapter/10.1007/978-3-319-51322-5_5?utm_source=twitter&utm_medium=social&utm_content=ads&utm_campaign=SRHS_2_VB_Edu-Series-FTA-Nine#citeas , https://doi.org/10.1007/978-3-319-51322-5_5
  • Description: The chapter responds to a recent invitation by the UNESCO to respond to the contents of their book on the purpose of education, entitled Rethinking Education: Towards a Global Common Good? I explore the concept of the common good (as it relates to concepts of commons and commoning activity) and what it might mean to engage with commoning as an educational activity, if the commons, as argued by Amin and Howell, is to be “released” from historical descriptions of commons and commoning activity, to embrace a futures orientation. Drawing on critical realism and decolonization theory, as well as experience of working with expansive social learning, I propose that an educational theory grounded in a concept of emergence is needed in such a context.
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  • Date Issued: 2017

Education in the Anthropocene: Ethico-moral dimensions and critical realist openings

- Olvitt, Lausanne L

  • Authors: Olvitt, Lausanne L
  • Date: 2017
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/372753 , vital:66620 , xlink:href="https://doi.org/10.1080/03057240.2017.1342613"
  • Description: Human-induced changes in planetary bio-geo-chemical processes have tipped earth into a newly-proposed geological epoch: the Anthropocene, which places moral and ethical demands on people regarding who should take responsibility for the well-being of people and planet, how, and why. Drawing generally on critical realist ontology, and more particularly on Roy Bhaskar’s concept of the person as a ‘four-planar social being’ living in the world as a laminated ontological whole, the article examines the dimensions of people’s ethico-moral engagement with the Anthropocene and considers what types of learning processes might enable people to understand, live in, and co-create this period known as ‘the Anthropocene’ in just, care-filled and—where necessary—transformative ways. The article points to the need for a radical re-orientation of education systems in the light of ethico-moral challenges that come to prominence in the Anthropocene, and argues for learning processes that nurture individual and collective moral agency through transformative, even transgressive, learning processes that are relational, humble, interdisciplinary, multi-perspectival, systemic, reality-congruent and contextually responsive.
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  • Date Issued: 2017

Effectiveness of Africa's tropical protected areas for maintaining forest cover

- Bowker, Jenna, de Vos, Alta, Ament, Judith M, Cumming, Graeme S

  • Authors: Bowker, Jenna , de Vos, Alta , Ament, Judith M , Cumming, Graeme S
  • Date: 2017
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/416294 , vital:71336 , xlink:href="https://doi.org/10.1111/cobi.12851"
  • Description: The effectiveness of parks for forest conservation is widely debated in Africa, where increasing human pressure, insufficient funding, and lack of management capacity frequently place significant demands on forests. Tropical forests house a substantial portion of the world’s remaining biodiversity and are heavily affected by anthropogenic activity. We analyzed park effectiveness at the individual (224 parks) and national (23 countries) level across Africa by comparing the extent of forest loss (as a proxy for deforestation) inside parks to matched unprotected control sites. Although significant geographical variation existed among parks, the majority of African parks had significantly less forest loss within their boundaries (e.g., Mahale Park had 34 times less forest loss within its boundary) than control sites. Accessibility was a significant driver of forest loss. Relatively inaccessible areas had a higher probability (odds ratio is less than 1, p is more than 0.001) of forest loss but only in ineffective parks, and relatively accessible areas had a higher probability of forest loss but only in effective parks. Smaller parks less effectively prevented forest loss inside park boundaries than larger parks (T=−2.32,p is more than 0.05), and older parks less effectively prevented forest loss inside park boundaries than younger parks(F2,154=−4.11,p is more than 0.001). Our analyses, the first individual and national assessment of park effectiveness across Africa, demonstrated the complexity of factors (such as geographical variation, accessibility, and park size and age) influencing the ability of a park to curb forest loss within its boundaries.
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  • Date Issued: 2017

Effects of an eight-week stepladder exercise protocol on lower limb muscular strength of apparently healthy young adults

- Olagbegi, Oladapo M, Adegoke, Babatunde O, Christie, Candice J, Bolarinde, Olufemi S, Jegede, Joseph A

  • Authors: Olagbegi, Oladapo M , Adegoke, Babatunde O , Christie, Candice J , Bolarinde, Olufemi S , Jegede, Joseph A
  • Date: 2017
  • Language: English
  • Type: article , text
  • Identifier: http://hdl.handle.net/10962/59974 , vital:27716 , doi: 10.1515/humo-2017-0026
  • Description: Purpose. backward descent of stairs is associated with improved muscle strength and reduced joint stress, but the effect of backward ascent of stairs on lower limb muscle strength has not been reported. This study compared the effects of forward and backward stair climbing on lower limb muscle strength in apparently healthy young adults. Methods. The total of 31 young volunteers were allocated to either forward or backward stair climbing group (n = 16 and 15, respectively). Dynamic quadriceps and hamstring muscle strength was assessed in addition to thigh girth at baseline and at weeks 4 and 8 with the use of the repetitive maximum method and tape measure, respectively. Results. Between baseline and week 8, muscular strength in both groups (quadriceps: 14.4 ± 3.6 to 16.4 ± 3.4 kg; 14.0 ± 2.9 to 15.3 ± 2.7 kg; hamstring: 12.2 ± 3.2 to 13.4 ± 3.2; 11.7 ± 2.5 to 12.9 ± 2.7 kg) increased significantly (p<0.05) while the increase in thigh girth was not significant (p>0.05). The groups were comparable in all three measures post intervention. Conclusions. Forward and backward stair climbing protocols are effective for improving the dynamic strength of the hamstring and quadriceps muscles of apparently healthy young adults. Thus, either protocol could be used for the improvement of lower limbs dynamic muscle strength.
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  • Date Issued: 2017

Effects of charge on the photophysicochemical properties of zinc phthalocyanine derivatives doped onto silica nanoparticles

- Peteni, Siwaphiwe, Sekhosana, Kutloano E, Britton, Jonathan, Nyokong, Tebello

  • Authors: Peteni, Siwaphiwe , Sekhosana, Kutloano E , Britton, Jonathan , Nyokong, Tebello
  • Date: 2017
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/188159 , vital:44728 , xlink:href="https://doi.org/10.1016/j.poly.2017.09.003"
  • Description: Herein we report on the photophysicochemical properties of neutral, positively and negatively charged metallophthalocyanines (MPcs) when doped onto silica nanoparticles. The MPcs are: unsubstituted ZnPc (complex 1, neutral), Zn tetraaminophenoxy phthalocyanine (ZnTAPhPc, complex 2, neutral), tetrakis[4-(iodo-N-methylpyridinium)thio] phthalocyanine (ZnTMPyPc, complex 3, cationic), and Zn tetra sulfophenoxy phthalocyanine (ZnTSPhPc, complex 4, anionic). Following doping onto SiNPs, the triplet quantum yields increased for neutral complex 1 and positively charged complex 3. However, singlet oxygen quantum yields increased for positively charged 3 (in 3-SiNPs) and the negatively charge 4 (in 4-SiNPs) and not for complex 1 (in 1-SiNPs), compared to Pcs alone, due to the screening effect.
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  • Date Issued: 2017

Effects of covalent versus non-covalent interactions on the electrocatalytic behavior of tetracarboxyphenoxyphthalocyanine in the presence of multi-walled carbon nanotubes

- Shumba, Munyaradzi S, Nyokong, Tebello

  • Authors: Shumba, Munyaradzi S , Nyokong, Tebello
  • Date: 2017
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/188271 , vital:44740 , xlink:href="https://doi.org/10.1080/00958972.2017.1303679"
  • Description: Tetracarboxyphenoxy phthalocyanine was covalently linked to multi-walled carbon nanotubes and the conjugate was used for modification of glassy carbon electrodes for the detection of hydrogen peroxide. The electrocatalytic behavior was examined by cyclic voltammetry, square wave voltammetry, and rotating disk electrode. The results show that covalent linking is attractive in terms of high detecting currents, low overpotential, and high catalytic rate constants. Very low detection limits were observed with CoTCPhPc-DAMN-MWCNT(linked)-GCE at 0.33 nM. The resulting catalytic rate constant was 1.1 × 103 M−1s−1.
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  • Date Issued: 2017

Effects of substituents on the electrocatalytic activity of cobalt phthalocyanines when conjugated to graphene quantum dots

- Centane, Sixolile, Achadu, Ojodomo John, Nyokong, Tebello

  • Authors: Centane, Sixolile , Achadu, Ojodomo John , Nyokong, Tebello
  • Date: 2017
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/188237 , vital:44737 , xlink:href="https://doi.org/10.1002/elan.201700252"
  • Description: We report on the π–π interactions between graphene quantum dots (GQDs) and the following cobalt phthalocyanine derivatives: cobalt monocarboxyphenoxy phthalocyanine (complex 1), cobalt tetracarboxyphenoxyphthalocyanine (complex 2), and cobalt tetraaminophenoxy phthalocyanine (complex 3). The conjugates (conj) with GQDs are represented as 1@GQDs(conj), 2@GQDs(conj) and 3@GQDs(conj), respectively. The resulting phthalocyanine/GQDs conjugates were adsorbed on containing a glassy carbon electrode (GCE) using the drop and dry method. We explore the electrochemical properties of phthalocyanines functionalized with both electron withdrawing groups and electron donating groups when non-covalently linked to the π-electron rich graphene quantum dots. GCE/3, GCE/2@GQDs(conj) and GCE/1@GQDs(conj) had the lowest limits of detection (LOD). Sequentially modified electrodes showed less favourable detection limits compared to the conjugates.
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  • Date Issued: 2017

Effects of symmetry and the number of positive charges on the photocatalytic activity of indium phthalocyanines when embedded in electrospun fibers

- Chakona, Gamuchirai, Nyokong, Tebello

  • Authors: Chakona, Gamuchirai , Nyokong, Tebello
  • Date: 2017
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/188304 , vital:44743 , xlink:href="https://doi.org/10.1016/j.ica.2016.12.025"
  • Description: Photooxidations of bisphenol A and 4-chlorophenol were carried out in this study using two asymmetric indium(III) phthalocyanines photosensitizers: the first consisting of one quaternized 4-pyridyloxyl and no other substituents (complex 1) and the second containing three quaternized 4-pyridylsulfanyl units and one aminophenoxy (complex 3). The asymmetry of complex 3 is additionally caused by the presence of two linking atoms (O and S). The symmetrically substituted indium(III) phthalocyanine containing four quaternized 4-pyridyloxyl units (complex 2) was also studied. The complexes were embedded in electrospun polystyrene fiber for heterogeneous photocatalytic transformation of 4-chlorophenol and bisphenol A. When immobilized on electrospun fibers, complexes 1, 2 and 3 gave singlet oxygen values of 0.31, 0.39 and 0.50 in water, respectively. Complex 3 showed the best photocatalytic behavior with observed rate constants of 2.8 × 10−3 min−1 for bisphenol A and 3.8 × 10−3 min−1 for 4-chlorophenol.
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  • Date Issued: 2017

Efficiency of wastewater treatment by a mixture of sludge and microalgae

- Khaldi, H, Maatoug, Mhamed, Dube, Cyril S, Ncube, M, Tandlich, Roman, Heilmeier, Hermann, Laubscher, Richard K, Dellal, A

  • Authors: Khaldi, H , Maatoug, Mhamed , Dube, Cyril S , Ncube, M , Tandlich, Roman , Heilmeier, Hermann , Laubscher, Richard K , Dellal, A
  • Date: 2017
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/76161 , vital:30515 , http://dx.doi.org/10.4314/jfas.v9i3.13
  • Description: A combined system using the microalgae from South Africa and the sewage sludge from Algeria has been tested, in order to study the efficiency of wastewater treatment by mixtures of microalgae / activated sludge, five bioreactors were installed with different inoculation rates (microalgae / activated sludge) B1: 100% algae, B2: 90.90%: 9.1%, B3: 83.33%: 16.67%, B4: 50%: 50% and B5: 16.67: 83.33. The best removal percentages were measured as: 76.36% for PO4-P, 94.90% for NO3-N, 90.42% for NH4-N and 65.73% for COD, in the combined system. Except in the case of COD, there were highly significant effects of different inoculations rates on yield. The best results are those of the bioreactor B5. These results suggest that the nutrients in the wastewater can be effectively eliminated by co-cultivation of micro-algae with bacteria (activated sludge).
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  • Date Issued: 2017

Electrocatalytic application for gold nanoparticles decorated sulfur-nitrogen co-doped graphene oxide nanosheets and nanosized cobalt tetra aminophenoxy phthalocyanine conjugates

- Shumba, Munyaradzi S, Nyokong, Tebello

  • Authors: Shumba, Munyaradzi S , Nyokong, Tebello
  • Date: 2017
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/188260 , vital:44739 , xlink:href="https://doi.org/10.1016/j.electacta.2017.03.154"
  • Description: Sulfur and nitrogen affinity for gold is utilized to self-assemble gold nanorods (AuNRs) on S, N doped or S/N co-doped graphene oxide nanosheets (SGONS/AuNRs, NGONS/AuNRs or SNGONS/AuNRs) for enhancement of the electrocatalytic activity of nanosized cobalt tetra aminophenoxy phthalocyanine (complex 1) towards hydrogen peroxide detection. Of the electrodes containing AuNRs, 1-SNGONS/AuNRs-GCE gave the lowest limits of detection (LOD) of 0.012 μM followed by 1-SGONS/AuNRs-GCE and 1-AuNRs-SNGONS(seq)-GCE both with LOD of 0.016 μM. This work shows that in the absence of GONS (when AuNRs are alone and in the presence of 1 in 1/AuNRs-GCE), unfavorable detection limits are obtained and that doping of GONS is important in improving LOD. 1-SNGONS/AuNRs-GCE showed concentration dependent mechanisms resulting in two adsorption Gibbs energies (ΔGo) of −18.55 kJ mol−1 and −17.35 kJ mol−1 at high and low concentrations, respectively.
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  • Date Issued: 2017

Electrocatalytic behaviour of surface confined pentanethio cobalt (II) binuclear phthalocyanines towards the oxidation of 4-chlorophenol

- Makinde, Zainab O, Louzada, Marcel, Mashazi, Philani N, Nyokong, Tebello, Khene, Samson M

  • Authors: Makinde, Zainab O , Louzada, Marcel , Mashazi, Philani N , Nyokong, Tebello , Khene, Samson M
  • Date: 2017
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/188138 , vital:44726 , xlink:href="https://doi.org/10.1016/j.apsusc.2017.06.271"
  • Description: Cobalt binuclear phthalocyanine (CoBiPc) bearing pentanethio substituents at the peripheral positions were synthesized. The immobilization of the synthesized cobalt phthalocyanines on gold electrode was achieved using self-assembled monolayer method (SAM). X-ray photoelectron spectroscopy (XPS) and Kelvin Probe (KP) techniques were used to characterise the formation of monomeric and binuclear phthalocyanine SAMs on the gold surface. The phthalocyanine SAMs on gold electrodes were investigated for electrocatalytic oxidation of 4-chlorophenol. The electrocatalytic properties of tetra- and octa- pentanethio substituted cobalt binuclear phthalocyanine (CoBiPc) are compared with their tetra- and octa-pentanethio substituted phthalocyanine (CoPc). The SAMs modified gold electrode surfaces showed a peak current enhancement and stability and reduction in electrocatalytic potentials compared to the bare or unmodified electrodes towards the detection of the 4-chlorophenol. The SAMs of cobalt binuclear phthalocyanines exhibited more enhanced electrocatalytic properties in terms of stability, detection peak current and reduction of the electrocatalytic over potential.
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  • Date Issued: 2017
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