An assessment of the implementation of intervention programmes which ensure the right to education for orphans in King Williams Town District
- Authors: Ntshuntshe, Zoleka
- Date: 2012
- Subjects: Student assistance programs
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/24661 , vital:63399
- Description: The purpose of the study was to assess the implementation of intervention programmes that ensure the right to education for orphans in schools in the King William’s Town District. Data from the study revealed that there were a number of challenges faced by orphans with regards to accessing social grants and this affected their school performance negatively. Some of the challenges were (1) even though orphans were receiving the social grant, it was inadequate to provide for their home and school needs; (2) there was lack of information by applicants to access documents they needed to apply for social grants. This was an impediment to access to funds from social grants. (3) The long distances travelled by people to reach social services posed obstacles to those wishing to apply for grants. (4) Applicants lacked proper documentation such as birth certificates and parents’ death certificates which could impede application processes for social grants and (5) Lack of monitoring of social grants resulted in the misuse of funds by some caregivers. In the schools it was also established that there was irregular distribution of food parcels which resulted from some people who gave food to their families and friends, leaving the needy ones out. The No fee policy however was a success as most learners were able to remain in school. With regard to school attendance, some of the challenges were: (1) that some learners were struggling to buy school books as this was not covered by the policy. (2) There was slow implementation of scholar nutrition programme with some schools in quintile 1-3 still not being able to benefit from the programme. (3) Scholar transport was not available to most of the learners and (4) learners were without counseling services, since teachers were not trained in psychosocial support. Nonetheless, social workers were adequately trained to provide psychosocial support to learners. In addition, non governmental organizations contributed a vital service by providing orphans with uniforms and food. However their work was limited by resources and funding. The study was situated in the interpretive paradigm which seeks to construct detailed descriptions of reality. The qualitative methods were suitable for data collection purposes because they allowed the use of interviews which collected detailed, authentic information of what goes on in the schools. It was therefore the best method for the research study which seeks to assess implementation of intervention programmes for orphans as they related the challenges they encounter in the implementation of intervention programmes in their schools. Purposive sampling was used to select 8 orphans, 8 caregivers, 4 principals, 4 teachers and 4 social workers from the 4 schools in the district. The study recommends that the Child Support Grant be reviewed upwards and that monitoring be strengthened so that grants are not misused. It is further recommended that the department of social services synchronize its information dissemination strategies with other stakeholder departments, such as the department of education so as to benefit orphans. It is also recommended that the No fee policy be strengthened by such additions as providing books for orphans and other vulnerable children in schools. Finally the study recommends scholar transport to be implemented as learners still have to walk long distances to school. , Thesis (MEd) -- Faculty of Education, 2012
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- Date Issued: 2012
An Investigation into the Management of Efficient Reading of Learners in Nelson Mandela Schools
- Authors: Nomajoko, Nothenjana Albertina
- Date: 2012
- Language: English
- Type: Masters theses , text
- Identifier: http://hdl.handle.net/11260/2952 , vital:43096
- Description: Reading has become centre of debate amongst teachers, principals, parents, departmental officials and the entire community of South Africa who are interested in education. Public concern over the teaching of reading has mounted in response to inflammatory statements and articles in popular media across the world. According to a statement in South African teachers’ newsletter about 35% of the children in public schools of this country were reported to have reading difficulties. Even the South African Minister for Basic Education, Angie Motshega, in her public statement on grade 12 results in 2010, mentioned reading as the major problem leading to high failure rate. Being a language teacher the researcher in this study believes every learner can read and write on completion of Foundation Phase Level in our schools and that every teacher can help learners with reading and writing difficulties. This study aims to identify the strategies that help teachers to be able to teach reading effectively and efficiently. This study will be of great value to the society at large. Teachers will benefit from this study as various teaching strategies to teach reading will be exposed. The main focus of this study was to explore the factors contributing towards efficient, effective and successful reading of learners in a well-resourced classroom and well equipped teacher. Foundation Phase is where learners acquire the most important skills for lifelong learning. The reading program is a necessity for every public school. A qualitative investigation was undertaken with the purpose to expose the strategies that help teachers in Nelson Mandela Schools (NMS). The study was undertaken in two schools that are in the reading program under the Nelson Mandela Institute (NMI) . The schools were conveniently sampled as the researcher is in one of the schools, so as to obtain easy access. The principals of the two schools and the Foundation Phase teachers were identified as the participants since the program is focusing mainly in the phase. Qualitative data were collected through questionnaires and semi-structured interviews. The outcomes pointed out that parental involvement in their children’s learning is seen as a major contributing factor in learners reading and writing efficiency. The well resourced classrooms and well equipped teachers are also contributing. , Thesis (MMED) -- Faculty of Educational Sciences, 2012
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- Date Issued: 2012
Bridging and enriching top-down and participatory learning: The case of smallholder, organic conservation agriculture farmers in Zimbabwe
- Authors: Mukute, Mutizwa
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432967 , vital:72919 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122261"
- Description: This article discusses the combined use of top-down and participatory learning approaches during the course of a 42-month organic conservation agriculture project that is being implemented in eight districts of Mashonaland East Province in Zimbabwe. The initial 18-month project was extended by a further 24 months in order to build on what had been achieved by deepening organic conservation agriculture practices, by increasing the understanding of, and access to, markets, and by expanding farmer agency. The top-down approach involves farmer representatives, known as ‘access farmers’ in the project, undergoing training at training centres and then returning to their respective farmer associations to train other farmers in what they have learnt. Participatory learning includes farmer-to-farmer learning within and among associations, and trainers learning from, and acting on, farmer experiences. Expansive learning, which combines, and goes beyond, both approaches and allows for joint learning, innovation and agency, has been used to support the associations to learn about, practise and benefit from organic conservation agriculture. This was stimulated by change laboratory workshops being conducted with each of the 32 farmer associations formed during the first 18 months of the project. The main argument in the present article is that combining these seemingly opposite approaches to learning is feasible and is essential for accelerating practice-oriented changes in agriculture. The concept that appears to enable this linkage is dialectics.
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- Date Issued: 2012
CdTe quantum dots functionalized with 4-amino-2, 2, 6, 6-tetramethylpiperidine-N-oxide as luminescent nanoprobe for the sensitive recognition of bromide ion
- Authors: Adegoke, Oluwasesan , Hosten, Eric C , McCleland, Cedric , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/244393 , vital:51253 , xlink:href="https://doi.org/10.1016/j.aca.2012.01.040"
- Description: A novel bromide ion-selective modified nanoprobe sensor based on 4-amino-2,2,6,6-tetramethylpiperidine-N-oxide (4AT)-functionalized CdTe quantum dots (QDs-4AT) has been developed. Fluorescence quenching of the QDs by 4AT was observed. The functionalized QDs-4AT nanoprobe allowed a highly sensitive determination of bromide ion via analyte-induced change in the photoluminescence (fluorescence recovery) of the modified QDs. A detection limit of 0.6 nM of bromide ion was obtained, while the interfering effect of other inorganic cations and anions was investigated to examine the selectivity of the nanoprobe. The linear range was between 0.01 and 0.13 μM. Combined fluorescence lifetime and electron paramagnetic resonance measurements confirmed electron transfer processes between bromide ion and QDs-4AT.
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- Date Issued: 2012
Characterization of 2,(3)-tetra-(4-oxo-benzamide) phthalocyaninato cobalt (II)—single walled carbon nanotube conjugate platforms and their use in electrocatalysis of amitrole
- Authors: Mugadza, Tawanda , Arslanoğlu, Yasin , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/244382 , vital:51252 , xlink:href="https://doi.org/10.1016/j.electacta.2012.02.041"
- Description: In this paper we report on the use of carboxylic acid functionalized single walled carbon nanotubes (SWCNT) in the synthesis of 2,(3)-tetra-(4-oxo-benzamide)phthalocyaninato cobalt (II)–single walled carbon nanotube conjugates (CoTOBPc–SWCNT), their characterization and application in the electrocatalytic oxidation of amitrole. Cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy were used for the detection of amitrole on the modified glassy carbon electrode. The catalytic rate constant was 1.6 × 103 M−1 s−1 and the apparent electron rate transfer constant was 1.5 × 10−5 cm s−1. The linear dynamic range was 1.0 × 10−6–3.0 × 10−5 M, with a sensitivity of ∼1.13 A mol−1 L cm−2.
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- Date Issued: 2012
Climate change and food security in Zimbabwe: a case of small-scale farmers in Mtambi ward, Zvishavane district
- Authors: Mugiya, Davidson
- Date: 2012
- Subjects: Climatic changes -- Zimbabwe , Farms, Small -- Zimbabwe , Food security -- Zimbabwe
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/29278 , vital:77711
- Description: The issue of climate change has recently gained much momentum particularly in marginalised regions and its impact threatens to deepen, making the future of agriculture bleak without adaptation. Agriculture might be further trampled as the sector`s performance heavily depends on the climatic condition. This situation makes small-scale farmers who mostly depend on rain-fed agriculture more vulnerable, creating a cycle of food insecurity. As the impact of climate change threatens to intensify, it has been realised that adaptation is no longer an option but an essential as the effects are detrimental particularly to small-scale farmers.Thus, the central objective of the study was to explore the impact of climate change on food security and factors affecting adaptation among small-scale farmers in Mtambi ward, Zvishavane District. The study adopts the Food Systems Theory and the Sustainable Livelihoods Approach as analytical frameworks to explain the interaction between small-scale farmers and environmental shocks in the context of food security. A qualitative method is adopted to get a comprehensive depiction of the plight of small-scale farmers in the background of climate change and food security. The perception and innermost feelings of this vulnerable group was viewed as critical units of analysis. This study shows that climate change is negatively affecting food security among small-scale farmers and further compromises their ability to cope with the stress. The study argues that climate change has affected all determinants of food security notably food availability, accessibility and utilisation. This situation had far reaching implications for adaptation as farmers depend on their on-farm production for both consumption and income which further compromises their purchasing power on the market. Small-scale farmers are at the dilemma of coping with climate change for the achievement of food security without clear-cut aid channelled to them. Resource constrains, credit and inputs aid bottlenecks, coupled with contradiction of programs among other critical issues making adaptation difficult among-small scale farmers. Drawing from the findings, the study recommends that the government should embark on mutual partnerships with NGOs and other significant stake-holders for the best interests of small-scale farmers. This remains a critical condition for agriculture development in general and food insecurity eradication in particular for the benefit of affected groups. , Thesis (MSoc. Sci) -- Faculty of Social Sciences and Humanities, 2012
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- Date Issued: 2012
Comparison of carbon screen-printed and disk electrodes in the detection of antioxidants using CoPc derivatives
- Authors: Matemadombo, Fungisai , Apetrei, Constantin , Nyokong, Tebello , Rodríguez-Méndez, María Luz , de Saja, José Antonio
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/244371 , vital:51251 , xlink:href="https://doi.org/10.1016/j.snb.2012.02.088"
- Description: Cobalt phthalocyanine (CoPc) and cobalt phthalocyanine carboxylic derivatives (CoTCPc and CoOCPc) have been used as electrocatalysts for the detection of the antioxidants vanillic acid, caffeic acid, pyrogallol, and ascorbic acid on screen-printed carbon and disk electrode surfaces. The cobalt phthalocyanines were used to detect vanillic acid (with limit of detection ranging from 1.15 μM to 2.42 μM at potentials of 0.55–0.88 V vs. Ag|AgCl), caffeic acid (with limit of detection ranging from 1.17 μM to 2.20 μM at potentials of 0.30–0.81 V vs. Ag|AgCl), pyrogallol (with limit of detection ranging from 1.16 μM to 3.63 μM at potentials of 0.52–0.63 V vs. Ag|AgCl), and ascorbic acid (with limit of detection ranging from 1.16 μM to 1.58 μM at potentials of 0.34–0.46 V vs. Ag|AgCl). The kinetic studies also demonstrate diffusion-controlled processes at the electrode surface. The SPCE electrodes have better detection properties towards vanillic acid, caffeic acid, pyrogallol while the disk electrodes had better ascorbic acid detection properties as proven by kinetic studies. Both types CoPc-influenced electrodes show 100% discrimination of the antioxidants.
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- Date Issued: 2012
DBU-Mediated cleavage of aryl-and heteroaryl disulfides
- Authors: Nyoni, Dubekile , Lobb, Kevin A , Kaye, Perry T , Cairab, Mino R
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/448884 , vital:74768
- Description: The capacity of the nitrogen nucleophile, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) to reduce aryl- and heteroaryl disulfides to the corresponding mercaptans is demonstrated. While dicarboxylated disulfide analogues afford the mono-DBU disulfide salts, as confirmed by X-ray crystallography, the corresponding methyl esters are cleaved normally.
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- Date Issued: 2012
Effect of fluoroquinolones antibiotics on vancomycin and oxacillin resistant staphylococcus species in Eastern Cape Province
- Authors: Soyege, Oludotun
- Date: 2012
- Subjects: Staphylococcus aureus , Quinolone antibacterial agents , Fluoroquinolones
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/25349 , vital:64212
- Description: This study shows the susceptibility profile of some Staphylococcus species isolated from commensal Staphylococci in Nkonkobe municipality, South Africa. A total number of 120 Staphylococcal isolates were screened for their susceptibilities to various classes of antibiotics such as Aminoglycoside (Gentamycin), Aminoglycoside (Kanamycin), Macrolide (Erythromycin), Tetracycline (Minocycline), Anti-tuberculous (Rifampicin), Lincosamides (Clindamycin), Cephalosporin and Fluoroquinolones in general. During the study, 32 (26percent) the test organisms were susceptible to both methicillin and vancomycin, while 12 (10percent) had co-resistance to the antibiotics. Furthermore, Gentamycin (an Aminoglycoside) had a relatively high potency against the isolates with 107 (89.17percent) of the bacteria being susceptible to it, while 10 (8.33percent) were resistant. On the other hand, Erythromycin (a Macrolide) was active against 72 (60percent) of the isolates, while 5 (4.17percent) and 74 (61.67percent) of the isolates yielded intermediate and resistant responses respectively. In addition , 51 (42.5percent) of the isolates were susceptible to rifampicin, while 1 (0.83percent) and 17 (14.17percent) were intermediate and resistant respectively. Ten percent of the isolates screened for their antibiotic susceptibility pattern in this study were positive for mecA gene among the vancomycin-oxacillin resistant strains while van gene was not detected in any of the isolates. This shows how the synergy of both vancomycin and oxacillin contribute to some resistance nature of Staphylococci. In order to overcome this resistance attributes of Staphylococci, to the commonly used antibiotics as discussed under this context, various types of fluoroquinolones were tested. The result shows that less than 10percent of the isolates were generally resistant to the fluoroquinolones except against Nalidix acid to which all the isolates were resistant. Other antibiotics had relatively higher resistance patterns as observed for minocycline (39.51percent), clindamycin (12.75percent), gentamycin (12.31percent) and vancomycin (12.3percent). The new generation fluoroquinolones including Gatifloxacin, Levofloxacin, Moxifloxacin and Ciprofloxacin to which less than 5percent of the bacteria are resistant gives some clinical advantage over the Methicillin and Vancomycin resistant strains. About 31percent of the isolates had multiple antibiotic resistance index of ≥1 and suggests animals in the community as potential reservoirs of antibiotic resistance determinants in the environment. Data obtained in this study is of epidemiological importance and valuable for disease control. , Thesis (MSc) -- Faculty of Science and Agriculture, 2012
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- Date Issued: 2012
Effectiveness of housing delivery in the Reconstruction and Development Programme in Duncan Village
- Authors: Millie, Lindile Churchill
- Date: 2012
- Subjects: Housing development -- South Africa , Public housing -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/24199 , vital:62441
- Description: The primary objective of this study was to determine the effectiveness of Housing delivery in the Reconstruction and Development Programme in Duncan Village. This thesis has tried to answer to why there are still places like Duncan Village, situated at the heart of Buffalo City Metropolitan Local Municipality, in the Eastern Cape Province with alarming rate at which the “shanty resident” has been growing and showing no signs of coming to an end? The researcher used both qualitative and quantitative approaches in this research. The researcher conducted the research using officials from the Department of Human Settlements, officials from Buffalo City Metropolitan Municipality, Ward Councillor, and Duncan Village community. , Thesis (MPA) -- Faculty of Management and Commerce, 2012
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- Date Issued: 2012
Electrocatalytic behavior of cobalt phthalocyanine complexes immobilized on glassy carbon electrode towards the reduction of dicrotophos pesticide
- Authors: Vilakazi, Sibulelo , Nyokong, Tebello , Fukuda, Takamitsu , Kobayashi, Nagao
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/245832 , vital:51409 , xlink:href="https://doi.org/10.1142/S1088424612501040"
- Description: Electrocatalytic properties of cobalt phthalocyanine (CoPc), cobalt tetra-carboxy phthalocyanine (CoTCPc) and cobalt octa-carboxy (CoOCPc), towards the detection of dicrotophos have been studied. Catalytic behavior towards the reduction of dicrotophos was found to be dependent on the pH, as well as the substitution on the phthalocyanine ring. Strong electron withdrawing groups on the phthalocyanine ring yielded best catalysis as evidenced by the enhancement of the reduction peak current, (~5 fold) compared to the bare glassy carbon electrode. The analysis gave a good detection limit of 1.25 × 10-7 M, and good linearity for the studied concentration range. A high Tafel slope value was obtained, indicating a strong interaction between dicrotophos and the cobalt phthalocyanine complex.
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- Date Issued: 2012
Electrospun polyacrylic acid polymer fibers functionalized with metallophthalocyanines for photosensitizing and gas sensing applications
- Authors: Zugle, Ruphino , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/243543 , vital:51162 , xlink:href="https://doi.org/10.1080/10601325.2012.662006"
- Description: The photophysical and photochemical properties of tetraaminophthalocyanine complexes of lutetium and zinc covalently linked to polyacrylic acid were studied alongside those of unsubstituted zinc phthalocyanine within the same polymeric fiber matrix. All three phthalocyanines within the solid fiber matrices showed photoactivity by the generation of singlet oxygen as was observed in solution. The fluorescence behaviors of the composite fibers equally parallel those in solution. For the unsubstituted zinc phthalocyanine composite, the fiber showed fluorescence quenching on interaction with gaseous nitrogen dioxide similar to that in DMF and, thus could be a promising nanofabric material in developing optoelectronic devices that are responsive to the gas.
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- Date Issued: 2012
Facile deposition of gold nanoparticle thin films on semi-permeable cellulose substrate
- Authors: Sosibo, Ndabenhle , Mdluli, Phumlani , Mashazi, Philani N , Tshikhudo, Robert , Skepu, Amanda , Vilakazi, Sibulelo , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/242638 , vital:51063 , xlink:href="https://doi.org/10.1016/j.matlet.2012.08.043"
- Description: This study reports the facile method for the deposition of gold nanoparticle thin film onto a monoporous semi-permeable cellulose membrane through the diffusion of borohydride ions leading to the reduction of AuCl4− ions. The synthesis of gold nanoparticle thin film was deposited on one side of the membrane that was exposed to AuCl4− ions while the other side containing a reducing agent remained clear. The gold nanoparticle thin film exhibited a broad surface plasmon resonance (SPR) peak at 529 nm. Various characterization techniques were employed and all demonstrated the presence of gold thin film. The reported method represents a simplistic method for the deposition of gold nanoparticle thin films and various other metal nanoparticles may be deposited following this method.
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- Date Issued: 2012
Firm age, collateral value, and access to debt financing in an emerging economy: evidence from South Africa
- Authors: Ezeoha, Abel E , Botha, Ferdi
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/396060 , vital:69147 , xlink:href="https://hdl.handle.net/10520/EJC31367"
- Description: This paper applies the Blundell and Bond system generalised method of moments (GMM) two-step estimator to examine the impact of age and collateral value on debt financing, using a panel of 177 non-financial companies listed on the Johannesburg Stock Exchange over the period 1999 to 2009. The results show that South African firms have target leverage ratios and adjust their capital structures from time to time to achieve their respective targets, that the relationship between firm age and debt financing is non-monotonic, and that firms with higher collateral value are likely to face fewer constraints on borrowing and therefore have greater access to medium-term and long-term debts. Robustness tests also reveal that during start-up and maturity stages, a firm's access to debt markets is significantly influenced by investments in assets that are acceptable to external creditors as collateral. These findings suggest that debt financing policies could be more critical for firms in the start-up and maturity stages.
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- Date Issued: 2012
Higher education, academic communities, and the intellectual virtues
- Authors: Jones, Ward E
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/275647 , vital:55066 , xlink:href="https://doi.org/10.1111/edth.12005"
- Description: Because higher education brings members of academic communities in direct contact with students, the reflective higher education student is in an excellent position for developing two important intellectual virtues: confidence and humility. However, academic communities differ as to whether their members reach consensus, and their teaching practices reflect this difference. In this essay, Ward Jones argues that both consensus-reaching and non-consensus-reaching communities can encourage the development of intellectual confidence and humility in their students, although each will do so in very different ways.
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- Date Issued: 2012
How do HIV and AIDS impact the use of natural resources by poor rural populations?: The case of wild animal products
- Authors: Kaschula, Sarah A H , Shackleton, Charlie M
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182344 , vital:43822 , xlink:href="https://hdl.handle.net/10520/EJC97203"
- Description: As a result of heightened financial and food insecurity, populations adversely affected by HIV and/or AIDS may be more likely to utilise wild natural resources to supplement their diet and livelihoods. Should this effect be pronounced, HIV and AIDS may pose a serious environmental threat. We explored the hypothesis that the presence of factors in the household, such as chronic illness in and recent mortality of individuals in a high HIV-risk age group, as well as the fostering of orphans, are associated with increased utilisation of wild animal products (WAPs) at the household level. We randomly surveyed 519 households from four sites in rural South Africa, recording household socio-economic status, the utilisation of wild animal products and health and demographic factors attributed to HIV or AIDS. Binary logistic regressions were used to test if households with markers of HIV and/or AIDS affliction were more likely to have a higher incidence and frequency of WAP utilisation relative to non-afflicted households, after adjusting for socio-economic and demographic variables. We found that, although households with markers of HIV and/or AIDS were generally poorer and had higher dependency ratios, there was no evidence to support the hypothesis that WAP harvesting was associated with either poverty, or markers of HIV and/or AIDS affliction. Our findings suggest that generalisations about a possible interaction between HIV and/or AIDS and the environment may not uniformly apply to all categories of natural resources or to all user groups.
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- Date Issued: 2012
Imidazole-functionalized polymer microspheres and fibers–useful materials for immobilization of oxovanadium (IV) catalysts
- Authors: Walmsley, Ryan S , Ogunlaja, Adeniyi S , Coombes, Matthew J , Chidawanyika, Wadzanai J U , Litwinski, Christian , Torto, Nelson , Nyokong, Tebello , Tshentu, Zenixole R
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/246041 , vital:51431 , xlink:href="https://doi.org/10.1039/C2JM15485D"
- Description: Both polymer microspheres and microfibers containing the imidazole functionality have been prepared and used to immobilize oxovanadium(IV). The average diameters and BET surface areas of the microspheres were 322 μm and 155 m2 g−1 while the fibers were 1.85 μm and 52 m2 g−1, respectively. XPS and microanalysis confirmed the incorporation of imidazole and vanadium in the polymeric materials. The catalytic activity of both materials was evaluated using the hydrogen peroxide facilitated oxidation of thioanisole. The microspheres were applied in a typical laboratory batch reactor set-up and quantitative conversions (>99%) were obtained in under 240 min with turn-over frequencies ranging from 21.89 to 265.53 h−1, depending on the quantity of catalyst and temperature. The microspherical catalysts also proved to be recyclable with no drop in activity being observed after three successive reactions. The vanadium functionalized fibers were applied in a pseudo continuous flow set-up. Factors influencing the overall conversion and product selectivity, including flow rate and catalyst quantity, were investigated. At flow rates of 1–4 mL h−1 near quantitative conversion was maintained over an extended period. Keeping the mass of catalyst constant (0.025 g) and varying the flow rate from 1–6 mL h−1 resulted in a shift in the formation of the oxidation product methyl phenyl sulfone from 60.1 to 18.6%.
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- Date Issued: 2012
In vitro photodynamic effect of aluminum tetrasulfophthalocyanines on melanoma skin cancer and healthy normal skin cells
- Authors: Maduray, Kaminee , Odhay, Bharti , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/245762 , vital:51403 , xlink:href="https://doi.org/10.1016/j.pdpdt.2011.07.001"
- Description: Photodynamic therapy is a medical treatment that uses an inactive dye/drug and lasers as a light source to activate the dye/drug to produce a toxic form of oxygen that destroys the cancer cells. This study aimed at investigating the cytotoxic effects of different concentrations of aluminum tetrasulfophthalocyanines in its inactive and active state (laser induced) on melanoma skin cancer cells, healthy normal skin fibroblast and keratinocyte cells. Experimentally, 3 x 10(4) cells/ml were seeded in 24-well plates before treatment with different concentrations of aluminum tetrasulfophthalocyanines. After 2 h, cells were irradiated with a light dose of 4.5 J/cm(2). Post-irradiated cells were incubated for 24 h before cell viability was measured using the CellTiter-Blue Viability Assay. Results showed that aluminum tetrasulfophthalocyanines at high concentrations were cytotoxic to melanoma cells in the absence of laser activation. In the presence of laser activation of aluminum tetrasulfophthalocyanines at a concentration of 40 mu g/ml decreased cell viability of melanoma cells to 45%, fibroblasts to 78% and keratinocytes to 73%. At this photosensitizing concentration of aluminum tetrasulfophthalocyanines the efficacy of the treatment light dose 4.5 J/cm(2) and the cell death mechanism induced by photoactivated aluminum tetrasulfophthalocyanines was evaluated. A light dose of 4.5 J/cm(2) was more efficient in killing a higher number of melanoma cells and a lower number of fibroblast and keratinocyte cells than the other light doses of 2.5 J/cm(2), 7.5 J/cm(2) and 10.5 J/cm(2). Apoptosis features such as blebbing, nucleus condensation, nucleus fragmentation and the formation of apoptotic bodies were seen in the photodynamic therapy treated melanoma skin cancer cells. This in vitro photodynamic therapy study concludes that using aluminum tetrasulfophthalocyanines at a photosensitizing concentration of 40 mu g/ml in combination with a laser dose of 4.5 J/cm(2) was potentially lethal for melanoma skin cancer cells and less harmful for the normal healthy skin cells. (c) 2011 Elsevier B.V. All rights reserved.
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- Date Issued: 2012
Interaction of CdTe quantum dots with 2, 2-diphenyl-1-picrylhydrazyl free radical
- Authors: Adegoke, Oluwasesan , Chidawanyika, Wadzanai J U , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/245751 , vital:51402 , xlink:href="https://doi.org/10.1007/s10895-011-1012-2"
- Description: The interaction of 2,2-diphenyl-1-picrylhydrazyl (DPPH●) free radical with thiol-capped CdTe quantum dots (QDs) has been studied by UV–vis spectroscopy, steady state and time resolved fluorescence measurements. Addition of DPPH● radical to CdTe QDs resulted in fluorescence quenching. The interaction occurs through static quenching as this was confirmed by fluorescence lifetime measurements. Time course absorption studies indicates that DPPH● may be reduced by interaction with QDs to the substituted hydrazine form (2,2-diphenyl-1-picrylhydrazine) DPPH-H. The mechanism of fluorescence quenching of CdTe QDs by DPPH● is proposed.
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- Date Issued: 2012
Investigating water knowledge flow to communities
- Authors: Burt, Jane C , Berold, Robert
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/433013 , vital:72923 , xlink:href="https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/KV%20288-11.pdf"
- Description: Those of us who work in water resource management have found that very few knowledge/research resources are accessible to most people. This happens because resources are not disseminated properly (or at all), or because they are inappropriately technicist, or because potential readers are hampered by low education. What is the best way to make water research accessible to as many people as possible and especially to people whose lives would be affected by the research? In the early 1980s an attempt was made to address this issue when Robert Berold edited People's Workbook (EDA 1981), a user-friendly book that presented basic technical information for rural people – not only on water, but also on agriculture, health, building construction, and income generation. The book included real-life interviews, and was disseminated by rural fieldworkers. Perhaps because there was nothing like it at the time, it was enormously popular.
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- Date Issued: 2012