Electrocatalytic studies of covalently immobilized metal tetra-amino phthalocyanines onto derivatized screen-printed gold electrodes
- Authors: Mashazi, Philani N , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/249059 , vital:51774 , xlink:href="https://doi.org/10.1007/s00604-010-0438-6"
- Description: Metal tetra-amino phthalocyanine complexes (MTAPc; where M is Co or Mn) were immobilized on screen-printed gold electrodes pre-modified with monolayers of benzylamino groups. The functionalized electrodes were then activated using benzene-1,4-dicarbaldehyde as a linker before MTAPc complexes were immobilized. The surface coverages for the modified electrodes confirmed the perpendicular orientation of the MTAPcs. The apparent electron transfer constant (kapp) for the electrodes is 2.2 × 10−5 cm.s−1 for both CoTAPc and MnTAPc modified electrodes as calculated with data from impedance measurements. The kapp values for the bare and benzylamino modified electrodes were found to be 1.2 × 10−4 cm.s−1 and 4.9 × 10−6 cm.s−1, respectively. The electrocatalysis of the modified electrodes towards detection of H2O2 gave significant peak current densities and electrocatalytic potentials at −0.28 V and −0.31 V for the MnTAPc and CoTAPc modified electrodes, respectively.
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- Date Issued: 2015
Becoming African: debating post-apartheid white South African identities
- Authors: Matthews, Sally
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142409 , vital:38077 , DOI: 10.1080/14725843.2011.530440
- Description: The post-apartheid era necessitates the rethinking of white identities in South Africa. One way in which some white South Africans are seeking to redefine themselves is through describing themselves as African. However, claims by white South Africans that they too are Africans have been met with mixed responses from black South Africans. In this article I use contributions to an online university students' forum to explore ways in which some white South Africans are embracing an African identity and to consider ways in which some black South Africans are responding to white South Africans' shifting identities. I use contributions to this forum as a starting point to think about the possibilities and limitations that the embracing of an African identity has for the development of what Frankenberg calls ‘anti-racist forms of whiteness’ among white South Africans.
- Full Text:
- Date Issued: 2011
Developing visual images for communicating information aboutantiretroviral side effects to a low-literate population:
- Authors: Dowse, Roslind , Ramela, Thato , Barford, Kirsty-Lee , Browne, Sara H
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/156769 , vital:40048 , https://doi.org/10.2989/16085906.2010.530172
- Description: The side effects of antiretroviral (ARV) therapy are linked to altered quality of life and adherence. Poor adherence has also been associated with low health-literacy skills, with an uninformed patient more likely to make ARV-related decisions that compromise the efficacy of the treatment. Low literacy skills disempower patients in interactions with healthcare providers and preclude the use of existing written patient information materials, which are generally written at a high reading level. Visual images or pictograms used as a counselling tool or included in patient information leaflets have been shown to improve patients’ knowledge, particularly in low-literate groups. The objective of this study was to design visuals or pictograms illustrating various ARV side effects and to evaluate them in a low-literate South African Xhosa population. Core images were generated either from a design workshop or from posed photos or images from textbooks. The research team worked closely with a graphic artist. Initial versions of the images were discussed and assessed in group discussions, and then modified and eventually evaluated quantitatively in individual interviews with 40 participants who each had a maximum of 10 years of schooling.
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- Date Issued: 2011
Effect of turbidity on the foraging success of Glossogobius callidus (Teleostei: Gobiidae)
- Authors: Parkinson, Matthew C , Booth, Anthony J
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124375 , vital:35600 , https://doi.org/10.2989/16085914.2011.589120
- Description: Particles suspended in water attenuate the light that passes through it via absorption or scattering (Utne-Palm 2002). For example, whereas algae absorb specific wavelengths of light necessary for photosynthesis, inorganic suspensoids tend to scatter light (Radke and Gaupisch 2005). This results in lowered ambient light levels and reduces the visual acuity of aquatic organisms. From a fish’s perspective, an increase in water turbidity has the potential to alter visually-mediated reproductive behaviours (Järvenpää and Lindström 2004), predator avoidance (Meager et al. 2006) and foraging success negatively (Utne-Palm 2002, Rowe et al. 2003, Sweka and Hartman 2003, Stuart-Smith et al. 2004). The foraging success of various fish species was affected by increased turbidity through decreasing predator–prey encounter rates (Sweka and Hartman 2003) and through decreasing visual acuity whereby the distance at which prey are visually detected is reduced (Utne-Palm 2002).
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- Date Issued: 2011
"Fit for purpose": towards tracking the quality of university education of entry-level journalists
- Authors: Berger, Guy
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159835 , vital:40348 , DOI: 10.1080/02560054.2005.9653329
- Description: Debate about the extent to which university education should serve industry is an important consideration for institutions of higher learning in a transforming South Africa, and particularly for those teaching would-be journalists. This issue can also be profitably analysed with reference to the current framework of the South African education authorities who argue that the quality of higher education institutions should be measured in terms of their “fit for purpose” to missions aligned to stakeholder interests in the transformation of the country as a whole. This criterion for quality assessment tends to focus on the educative processes within a university, but it can be argued that it ought to extend into the examination of the output consequences of journalism teaching. This would amount to not just fitness for purpose, but also achievement of purpose – and the latter including a creative and critical impact.
- Full Text:
- Date Issued: 2010
'I won't be squeezed into someone else's frame': Stories of supervisor selection
- Authors: Harrison, Liz , McKenna, Sioux , Searle, Ruth
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187395 , vital:44629 , xlink:href="https://hdl.handle.net/10520/EJC15100"
- Description: Using a collection of stories from a group of women who belong to a PhD support group, this article tracks the issue of choosing a supervisor. These women are all academics and therefore had some claim to an "insider" status but as novice researchers they were also "outsiders". Their discussions around how and why they chose their supervisors highlight issues often underplayed or ignored in textbooks on postgraduate supervision. In particular, this article examines issues of knowledge, embodied subjectivity and power by following three questions that arise from the data : whose knowing is important; who should I be, and whose PhD is it?
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- Date Issued: 2010
'Rich man poor man': inter-household and community factors influencing the use of wild plant resources amongst rural households in South Africa
- Authors: Cocks, Michelle L , Bangay, Lindsey , Shackleton, Charlie M , Wiersum, K Freerk
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141211 , vital:37953 , DOI: 10.3843/SusDev.15.3:3
- Description: Biodiversity is recognised as an integral part of people's daily livelihoods. This study therefore aims to understand the use of NTFPs at an intricate level by determining what role these resources fulfil in six rural villages and 1011 households' livelihoods. It examines how the use of NTFPs are influenced by intra-household variables, such as wealth and gender, and inter-community variables, such as accessibility to the natural resource. The results reveal that approximately 4453 kg of wild material is used annually per household, of which 1598 kg is used for cultural purposes. The influence of vegetation type and differences between villages are statistically more significant than inter-household variables. At an inter-household level, an increase in the financial status of households did not result in a decrease in the use of natural resources, nor in the quantity of material used.
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- Date Issued: 2010
31P NMR kinetic study of the tandem cleavage of phosphonate esters by bromotrimethylsilane
- Authors: Conibear, Anne C , Lobb, Kevin A , Kaye, Perry T
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/449304 , vital:74810 , xlink:href="https://doi.org/10.1016/j.tet.2010.08.058"
- Description: 1H and 31P NMR methods have been used to access rate constants and activation parameters for each of the consecutive second-order silylation reactions involved in the overall transformation (1a→3a→4a), while computational optimisation of the rate constants obtained from the initial, linear phase of each reaction has permitted an excellent fit with the experimental data for the entire course of the reaction.
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- Date Issued: 2010
A framework for recuperation: HIV/AIDS and the Keiskamma Altarpiece
- Authors: Schmahmann, Brenda
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147593 , vital:38652 , https://doi.org/10.1162/afar.2010.43.3.34
- Description: South Africa has the largest number of people living with HIV of any nation in the world. While various conditions and circumstances have made South Africa especially susceptible to an HIV/AIDS pandemic, its leadership has not recognized the impact of the disease or found appropriate strategies to address rising rates of infection. Thabo Mbeki's presidency (1999—2008) and the appointment of Manto Tshabalala-Msimang as his health minister were disastrous in terms of the pandemic.
- Full Text:
- Date Issued: 2010
A Game Theoretic Framework for Cooperative Benefits in South Africa’s land redistribution process: a case of Northern Kwa-Zulu Natal Sugarcane Farmland Transfers (No. 308-2016-5118)
- Authors: Mbatha, Cyril N , Antrobus, Geoffrey G
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142958 , vital:38180 , https://ageconsearch.umn.edu/record/96156/
- Description: A good indicator of successful farm redistribution cases has to be the continuation of viable productivity rates in their post transfer periods. Continued productivity benefits all the stakeholders that are involved in the process. Unfortunately negative productivity levels have been reported in numerous South African land redistribution transfers in recent years. A game theoretic perspective is adopted to argue that cooperation among key stakeholders, which could be enforced through long term contracts between a land buyer, sellers and new owners, would lead to higher productivity levels and other benefits. Additional benefits would, for example, include market related prices paid by a buyer.
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- Date Issued: 2010
A histological description of ovarian recrudescence in two Labeo victorianus populations
- Authors: Booth, Anthony J , Hecht, Thomas
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123564 , vital:35455 , https://doi.org/10.2989/16085910409503813
- Description: The ovaries of Labeo victorianus are paired organs situated in the peritoneal cavity and suspended on either side of the midline by a mesovarium. A capsule, composed of dense, regularly-arranged collagen and elastic fibres mixed with a few smooth muscle cells, enclosed the ovaries and gave off connective tissue septa, forming the ovigerous lamellae, which contained germ and follicle cells. Eight discrete stages of recrudescence were identified: oogonia, chromatin nucleolar oocytes, perinucleolar oocytes, primary yolk vesicle oocytes, secondary yolk vesicle oocytes, tertiary yolk vesicle oocytes, post-ovulatory follicles and atretic oocytes. Ovulation seemed to be synchronised with the onset of rainfall, with some deviations in the Sio River population. Gonadosomatic index variation followed a bimodal pattern, with maxima between January–February and between September–October for both populations. The same pattern was exhibited for both rainfall and water levels at the two study sites. Successful ovulation was followed by the formation of post-ovulatory follicles and Type I atresia, while failed spawning was characterised by Type II atresia. Clearance of post-ovulatory follicles was by phagocytosis and formation of melanomacrophage centres. There were variations in post-ovulatory changes between the two populations. Reproductive patterns in the Kagera River population conformed to the ‘norm’ in African labeines of the synchronisation of spawning with rainfall. Slight deviations from this pattern were, however, observed in the Sio River population where spawning occurred prior to the onset of rainfall.
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- Date Issued: 2010
A Proxy Approach for Interoperability and Common Control of Networked Digital Audio Devices
- Authors: Igumbor, Osedum P , Foss, Richard
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427099 , vital:72414 , https://www.aes.org/e-lib/browse.cfm?elib=15338
- Description: This paper highlights the challenge that results from the availability of a large number of control protocols within the context of digital audio networks. Devices that conform to different protocols are unable to communicate with one another, even though they might be utilizing the same networking technology (Ethernet, IEEE 1394 serial bus, USB). This paper describes the use of a proxy that allows for high-level device interaction (by sending protocol messages) between networked devices. Furthermore, the proxy allows for a common controller to control the disparate networked devices.
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- Date Issued: 2010
A tale of 2 investigations:
- Authors: Amner, Roderick J
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159438 , vital:40297 , https://hdl.handle.net/10520/EJC139354
- Description: This is a tale of two in-depth stories, both produced by one Daily Dispatch journalist, Gcina Nstaluba, in 2009. One was wildly successful - it helped change the face of the government's housing policy and won Ntsaluba SA Story of the Year at the 2010 Mondi Shanduka Newspaper Awards. The other was deemed a dismal failure by Ntsaluba himself. Why? And what can these stories teach us and our students about doing journalism in South Africa?
- Full Text:
- Date Issued: 2010
A watershed study on genetic diversity phylogenetic analysis of the Platypleura plumosa (Hemiptera Cicadidae) complex reveals catchment-specific lineages
- Authors: Price, Benjamin W , Barker, Nigel P , Villet, Martin H
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441711 , vital:73909 , https://doi.org/10.1016/j.ympev.2009.10.011
- Description: Historical biogeography studies have at their disposal a small suite of vicariance models to explain genetic differentiation within and between species. One of these processes involves the role of river catchments and their associated watersheds, in driving diversification and is applicable to both aquatic and terrestrial organisms. Although the idea of catchments structuring the genetic history of aquatic organisms is reasonably well understood, their effect on terrestrial organisms has largely been overlooked, with relevant studies being limited in scope. South Africa presents a perfect test-bed for elucidating this mechanism of diversification due to its rich biodiversity, range of climatic environments and many large river catchments. Here we use the cicadas of the Platypleura plumosa complex to highlight the importance of catchments and their associated watersheds in driving diversification of terrestrial invertebrates that lack an aquatic life-stage. Population structure was found to correspond to primary and in some cases secondary catchments; highlighting the need to include information on catchment structure when formulating hypotheses of population diversification. Recognizing that climate change in the near future is likely to alter the environment, and particularly precipitation patterns, insight into recent patterns of population change related to catchments may be useful in a conservation context.
- Full Text:
- Date Issued: 2010
Adult African sharptooth catfish, Clarias gariepinus, population dynamics in a small invaded warm-temperate impoundment
- Authors: Booth, Anthony J , Traas, Graham R L , Weyl, Olaf L F
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123596 , vital:35461 , https://doi.10.3377/004.045.0208
- Description: African sharptooth catfish, Clarias gariepinus (Burchell 1822), is a potamodromous species that is naturally distributed from Turkey to the Orange River, South Africa (Skelton 1993). It is omnivorous, feeding on plankton, vegetation, invertebrates, carrion and fish (de Moor & Bruton 1988) and may exhibit pack-hunting behaviour when foraging for small fish (Bruton 1979; Merron 1993). Clarias gariepinus is a large (>150 cm TL, >30 kg; Bruton 1976), long-lived (validated to at least 15 years, Weyl & Booth 2008) and fast-growing (Bruton & Allanson 1980; Quick & Bruton 1984; Richardson et al. 2009) fish that attains sexual maturity within two years of age (de Moor & Bruton 1988). It is eurythermic (80–35°C), mesohalic (0–10 ppt) and has the ability to airbreathe. These attributes predispose it to surviving in all but the most adverse of conditions and have directly contributed to its wide use as an aquaculture species. These attributes have also contributed to its ability to invade waterbodies beyond its natural range (de Moor & Bruton 1988) and after inadvertent introductions such as by escape from aquaculture facilities or through water transfer schemes, C. gariepinus has established populations in many non-native environments. Such invasions include the Philippines (Mercene 1997), Bangladesh (Arthur & Ahmed 2002), Thailand (Vidthayanon 2005), India (Bhakta & Bandyopadhyay 2007) and Brazil (Cambray 2005; Vitule et al. 2006; Rocha & Schiavetti 2007). In South Africa, C. gariepinus invaded the temperate Great Fish River catchment after the species was translocated from the Orange River through a Interbasin Water Transfer (IBWT) scheme (Laurenson et al. 1989). Potential threats include predation of and competition with indigenous species, habitat degradation, and the spread of diseases and parasites (Dudgeon et al. 2006).
- Full Text:
- Date Issued: 2010
Adult African sharptooth catfish, Clarias gariepinus, population dynamics in a small invaded warm-temperate impoundment
- Authors: Booth, Anthony J , Traasg, Graham L , Weyl, Olaf L F
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/446759 , vital:74558 , https://www.tandfonline.com/doi/abs/10.1080/15627020.2010.11657279
- Description: African sharptooth catfish, Clarias gariepinus, is a successful aquatic invader as it has a eurytopic physiology, is highly fecund, grows quickly and has an omnivorous diet. Despite possible threats that include predation of and competition with indigenous species, habitat degradation, and the spread of diseases and parasites, there is a lack of knowledge regarding its ecology and population dynamics within invaded systems. This study presents a mark–recapture experiment to investigate its population structure, natural mortality rate, population size and density within a population inhabiting a small, 76 ha invaded water supply reservoir in the temperate Eastern Cape region, South Africa.
- Full Text:
- Date Issued: 2010
An accidental but safe and effective use of Lucilia cuprina (Diptera: Calliphoridae) in maggot debridement therapy in Alexandria, Egypt
- Authors: Tantawi, Tarek I , Williams, Kirstin A , Villet, Martin H
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/442454 , vital:73986 , https://doi.org/10.1093/jmedent/47.3.491
- Description: The calliphorid fly, Lucilia cuprina (Wiedemann), is known to cause serious malign myiasis in animals, whereas its sibling species Lucilia sericata (Meigen) is commonly a carrion breeder and is used in maggot debridement therapy (MDT). The current study reports an accidental involvement of L. cuprina in MDT in Alexandria, Egypt, that has proved to be safe and effective. In November 2008, the laboratory colonies of L. sericata (the species regularly used in MDT) at the Faculty of Science, Alexandria University were renewed by Lucilia flies collected as third instar larvae on exposed rabbit carcasses. Flies from the new colonies were successfully used to heal the diabetic foot wounds of two patients at Alexandria Main University Hospital. Analysis of DNA sequences and adult and larval morphology then revealed that these flies were and still are L. cuprina. Breeding of this species in carrion in Alexandria is a new record. Despite the safety of this strain of L. cuprina in MDT, entomologists rearing blow flies for the purpose of wound debridement should regularly maintain high quality assurance of their species’ identity to avoid possible clinical complications that may result from the introduction of an unexpected and invasive species to their laboratory colonies.
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- Date Issued: 2010
An assessment of a light-attraction fishery in southern Lake Malawi
- Authors: Weyl, Olaf L F , Kazembe, Jacqueline , Booth, Anthony J , Mandere, D S
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123683 , vital:35472 , https://doi.org/10.2989/16085910409503787
- Description: This study provides the first quantitative assessment of the light-attraction component of a small-scale purse seine, locally known as a chilimira net, fishery in two areas of southern Lake Malawi. For monitoring purposes the shoreline of Lake Malawi is divided into a number of statistical strata. Two strata (‘2.1’ in the southeast arm and ‘3.1’ in the southwest arm of the lake) were selected for this study. Catch per unit effort in stratum 2.1 was generally lower than that recorded in stratum 3.1 but nets in stratum 2.1 fished more frequently, leading to similar annual catches in the two strata. Annual catch was estimated as 19.4 (CI = 15.9–23.5) tons net–1 year–1 in stratum 2.1 and 23.5 (CI = 19.5–28.1) tons net–1 year–1 in stratum 3.1 respectively. A total of 62 species from 28 cichlid genera, and 13 species from nine non-cichlid genera, were identified from the samples. Of the 37 genera identified, only five; Copadichromis, Dimidiochromis, Engraulicypris, Oreochromis and Rhamphochromis, contributed more than 5% to the total annual catch in either stratum. Their combined contribution to the annual catch was in excess of 85% in both strata. Comparisons showed that catch-composition was dependent on area. Length-frequency distributions of major target species in the catch showed that the fishery targeted juveniles in stratum 2.1, while in stratum 3.1 most individuals were harvested after reaching their lengthat-maturity. The dependence of catch-composition and size-selection on area indicates that management interventions for this fishery need to be area-specific. Since the fishery targets a diverse species assemblage, effort limitation or area closure may be the only viable management options, until such time as additional biological and fisheries data are available for the application of stock assessment models.
- Full Text:
- Date Issued: 2010
Applicability of the REALM health literacy test to an English second-language South African population:
- Authors: Dowse, Roslind , Lecoko, Motlalepule L E , Ehlers, Martina S
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/156798 , vital:40051 , https://doi.org/10.1007/s11096-010-9392-y
- Description: Objective and setting. To investigate health literacy in an English second language population using the REALM test, to evaluate its appropriateness and to compare health literacy between four different education categories. Setting Primary healthcare clinics and participant homes in Grahamstown, South Africa.
- Full Text:
- Date Issued: 2010
Applications of polymerized metal tetra-amino phthalocyanines towards hydrogen peroxide detection
- Authors: Mashazi, Philani N , Togo, Chumunorwa , Limson, Janice L , Nyokong, Tebello
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/261840 , vital:53451 , xlink:href="https://doi.org/10.1142/S1088424610001994"
- Description: This work reports the use of metallo tetra-amino phthalocyanines (MTAPc, M = Co and Mn) polymer thin films on gold and glassy carbon electrode surfaces for the detection and monitoring of hydrogen peroxide (H2O2). The polymer-modified electrodes were characterized using electrochemical and microscopic-based methods. Atomic force microscopy (AFM) was used to study the bare and polymer-modified ITO surfaces. The electrocatalytic reduction of H2O2 with glassy carbon polymer-modified electrodes gave higher current densities compared to their gold counterparts. The electroanalytical properties of H2O2 were obtained using a real-time calibration curve of the amperometric determination in pH 7.4 aqueous solution. The limits of detection (LoD) of the polymer-modified electrodes towards electroreduction of H2O2 were of the order of 10–7 M, with high sensitivity ranging from 6.0–15.4 mA.mM-1.cm-2.
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- Date Issued: 2010