A comparative photophysicochemical study of mono substituted phthalocyanines grafted onto silica nanoparticles
- Authors: Fashina, Adebayo , Antunes, Edith M , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193844 , vital:45399 , xlink:href="https://doi.org/10.1142/S1088424614500138"
- Description: In this study, we report on the covalent linking of carboxylic acid functionalized silica nanoparticles with zinc phthalocyanine mono-substituted non-peripherally and peripherally with either a 4-amino phenoxy (1, peripheral and 2, non-peripheral) or an amino group (3 peripheral). The grafting is achieved via the formation of an amide bond between the carboxylic acid of the silica nanoparticles and the amino group of the phthalocyanine complexes. The hybrid nanoparticles retained the amorphous nature of silica nanoparticles after conjugation. A slight decrease in fluorescence and a general improvement in triplet quantum yields compared to free Pcs were observed. Triplet lifetimes for 2-SiNPs and 3-SiNPs also improved when compared to the free phthalocyanine. The changes in singlet oxygen quantum yields upon conjugation were minimal.
- Full Text:
- Date Issued: 2014
A Note on the (Continued) Ability of the Yield Curve to Forecast Economic Downturns in South Africa
- Authors: Botha, Ferdi , Keeton, Gavin
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/395994 , vital:69142 , xlink:href="https://doi.org/10.1111/saje.12053"
- Description: In 2002-2003, the South African yield spread falsely signalled a downswing that never materialised. This paper provides two reasons for this false signal. First, while the Reserve Bank never actually officially declared the start of a downswing, by alternative measures a downswing did actually occur. It is this severe weakness in economic activity at that time that the yield curve pointed to. Second, short-term interest rates in 2003 were higher than they should have been because of a mistake made in measuring consumer price inflation. Because South Africa had recently introduced an inflation-targeting regime, policy interest rates were, as a result of this error, kept too high for too long. This policy mistake was rectified as soon as the error in the Consumer Price Index was discovered. Thus, the yield curve in 2003 pointed to the reality that short-term interest rates were too high and risked pushing the economy into full blown recession. This is demonstrated by the fact that it was a fall in long bond interest rates that caused the yield spread to turn negative, indicating expectations that short-term interest rates would need to be cut – as indeed they were.
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- Date Issued: 2014
A promising biological control agent for the invasive alien plant, Pereskia aculeata Miller (Cactaceae), in South Africa
- Authors: Paterson, Iain D , Mdodana, Lumka A , Mpekula, Ongezwa , Mabunda, Bheki D , Hill, Martin P
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/416806 , vital:71387 , xlink:href="https://doi.org/10.1080/09583157.2014.919439"
- Description: Pereskia aculeata Miller (Cactaceae) is an invasive alien plant from Central and South America that has become a problematic environmental weed in South Africa. A potential biological control agent, the stem-wilter, Catorhintha schaffneri Brailovsky and Garcia (Coreidae), was collected in southern Brazil and imported into quarantine in South Africa. Field host range data suggested that C. schaffneri has a host range restricted to P. aculeata. No-choice nymph survival tests were then conducted on 27 test plant species in 9 families. Survival to the adult stage was only recorded on P. aculeata and the closely related Pereskia grandifolia Haw. (Cactaceae). Mortality was significantly higher on P. grandifolia with only 3% of the nymphs reaching the adult stage compared with 74% on P. aculeata indicating that P. aculeata is the primary host plant. P. grandifolia is native in South America and is of no agricultural importance in South Africa so any feeding on P. grandifolia in South Africa would have no negative environmental or economic consequences. In other tests, adult survival on P. aculeata [25.8 days (SE ± 3.74)] was significantly longer than on other test plant species [4.3 days (SE ± 0.36)] further confirming the host specificity of the species. Impact studies conducted in quarantine indicated that C. schaffneri is damaging to P. aculeata, significantly reducing the number of leaves and the shoot lengths of plants, even at relatively low insect densities. C. schaffneri is safe for release in South Africa and is likely to be a damaging and effective agent.
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- Date Issued: 2014
A reflection on the use of case studies as a methodology for social learning research in sub Saharan Africa
- Authors: Cundill, Georgina , Lotz-Sisitka, Heila, 1965- , Mukute, Mutizwa , Ali, Million Belay , Shackleton, Sheona E , Kulundu-Bolus, Injairu M
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182832 , vital:43884 , xlink:href="https://doi.org/10.1016/j.njas.2013.04.001"
- Description: A recent review has highlighted that the methodology most commonly employed to research social learning has been the individual case study. We draw on four examples of social learning research in the environmental and sustainability sciences from sub-Saharan Africa to reflect on possible reasons behind the preponderance of case study research in this field, and to identify common elements that may be significant for social learning research more generally. We find that a common interest in change oriented social learning, and therefore processes of change, makes case studies a necessary approach because long term process analyses are required that are sensitive to social-ecological contexts. Common elements of the examples reflected upon included: a focus on initiating, tracking and/or understanding a process of change toward sustainability; long term research; an action research agenda that involves reflecting on data with research participants; and temporal, process based analysis of data coupled with in-depth theoretical analysis. This paper highlights that there is significant scope for exploratory research that compares case studies of social learning research to generate a deeper understanding of social learning processes, and their relationship to human agency and societal change.
- Full Text:
- Date Issued: 2014
A Study of grade 3 teachers' practices of developing learners' comprehension skills when teaching reading of isiXhosa in one selected junior primary school at Mdatsane in the Eastern cape: a case study
- Authors: Filita, Mandisa
- Date: 2014
- Subjects: Reading comprehension , Xhosa language , Teachers -- Training of -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/26448 , vital:65318
- Description: The problem of reading in South African schools has attracted the growing attention of researchers in South Africa and the entire world. Learners’ inability to read isiXhosa with understanding has become of major concern to the teachers, parents and the DoE. The root of the problem has been identified as the ineffective teaching of reading of isiXhosa in the schools, which result in learners’ consequent inability to independently apply comprehension skills to learn from reading across the curriculum. Furthermore, systemic barriers that exist in the education system seem to be another reason for learners’ reading problems in isiXhosa. Also there is the problem of the inadequately trained teachers in the home language of learners (isiXhosa) as they seemingly lack capacity to develop learners’ literacy to effective levels. In addition, many learners come from deprived print environments where texts are seldom part of their daily experience. The main aim of this study was to interrogate the practices undertaken by teachers in trying to develop comprehension skills of learners when reading in isiXhosa and the value they attach to reading generally and to the reading of isiXhosa in particular. The support teachers get from relevant stakeholders was also considered. The overall approach used was a qualitative approach. The study was structured according to the case study mode of enquiry, using the interpretive paradigm. The sampling used was purposive as I purposefully selected grade 3 teachers, as grade 3 is an exit grade in foundation phase. Furthermore, convenience sampling was also used for easy access, as the research site was the school where I work. The instruments used for data collection were semi-structured interviews and observations that were conducted in one junior primary school in a township context with four grade 3 teachers. It was found that as much as teachers’ practices have a contributing effect on learners’ inability to read isiXhosa with understanding, there are also various other factors which multiply the problem. The study reveals the following main findings: Firstly, the teachers believe that reading is a very important skill that needs to be developed with learners as all other learning is based on it. , Thesis (MEd) -- Faculty of Education, 2014
- Full Text:
- Date Issued: 2014
An assessment of the challenges facing the Eastern cape Nkonkobe Municipality in the provision of Adequate housing for the poor (2010- 2012)
- Authors: Mkiva, Nkosohlanga Matthew
- Date: 2014
- Subjects: Municipal services , Housing policy -- South Africa , Housing -- South Africa
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10353/25766 , vital:64477
- Description: The purpose of this study was to asses the challenges facing the Eastern Cape Nkonkobe Municipality in the provision of adequate housing for the poor. The study also aimed at suggesting mechanisms or strategies that could be applied to remedy the situation. It became evident throughout the study that the government has tried its best to fight against homelessness, but there are still thousands of people who do not have houses. The study was conducted through the use of a combination of the qualitative and quantitative research methods. Multiple methods were used with a view to increasing the reliability of observations. Twenty questionnaires were distributed to people at grassroots and ten questionnaires were distributed to the municipal officials. It has been noted in the study that community participation at all government levels is not taken seriously thus the housing problem in Nkonkobe Municipality. It is evident in the study that all the peoples’ projects in this municipality should be people-driven. It has also been pointed out that the service providers take a big slice of the municipal budget. The National Department of Human Settlement must also increase the budget that is allocated to the local municipalities so as to be able to spearhead housing delivery. This study will make a great contribution to the society in that all stakeholders will devise mechanisms to fight against housing challenges in the Nkonkobe Municipality. The municipal officials will devise workable solutions to the housing problem in Nkonkobe. This will change peoples’ lives and human dignity will be restored. , Thesis (MPA) -- Faculty of Management and Commerce, 2014
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- Date Issued: 2014
An assessment of the challenges to housing delievery in the Engcobo Municipality - Eastern Cape
- Authors: Jiyose, L
- Date: 2014
- Subjects: Housing policy -- South Africa , Public housing , Low-income housing
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10353/25613 , vital:64342
- Description: The intention of this study was to examine the challenges facing housing service delivery and its impact in Ngcobo Municipality. The study was also focusing on the factors that prevent/hinder the delivery of houses in Ngcobo. In this process the role of the different stakeholders has been identified and it became apparent that the spheres of government do not always complement each other or plan together. There was not a single window of co-ordination and this has resulted in a lack of support by National and Provincial government to the local sphere. The role of politicians and government officials and their lack of understanding of government policies has led to poor housing service delivery. In some instances their inability to work as a collective created tension and a lack of trust on the part of the community. This study has adopted both qualitative and quantitative research methods which are regarded as complementary. The findings that emerged from the study was that this housing service delivery project lacked integrated planning by the stakeholders. It is crucial and would make a significant difference if the Ngcobo Municipality were to review the results of the study and consider implementing its recommendations. The recommendations by the researcher relate to the areas of integrated planning, budgeting, execution, monitoring and evaluation. , Thesis (MPA) -- Faculty of Management and Commerce, 2014
- Full Text:
- Date Issued: 2014
Application of carbon black and iron phthalocyanine composites in bioelectricity production at a brewery wastewater fed microbial fuel cell
- Authors: Mshoperi, Edith , Fogel, Ronen , Limson, Janice
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431050 , vital:72740 , xlink:href="https://doi.org/10.1016/j.electacta.2013.11.01"
- Description: Aerobic cathode microbial fuel cells (MFCs) have been widely researched to provide bioremediation of wastewaters, coupled to sustainable energy production. In order to effectively accomplish this aim, suitable catalysts and catalyst supports for oxygen reduction reaction (ORR) are required. While iron phthaloycanine (FePc), supported on multi-walled carbon nanotubes has previously been studied for this function, cost of industrial production may hinder this. Importantly, this study examines the use of several available grades of carbon black for their relative suitability to perform as supports for FePc in MFC formats. Voltammetric studies showed that the different grades of carbon black provided varying lowering of the ORR overpotential, between ∼160 and ∼270 mV relative to unmodified GCEs, and an optimum grade (N326) was selected for further study. Carbon black/FePC composite electrodes exhibited comparable lowering of the ORR overpotential (606 mV) to potentials previously reported to nanotube/FePc composites (620 mV), as well as lowered charge-transfer resistance compared to electrodes solely modified with FePc. When applied as cathode modifiers in dual chambered MFCs utilising Enterobacter cloacae, the combined use of carbon black and FePc provided greater power densities than either alone; composite electrodes obtaining ∼400% power density, compared to unmodified electrodes. Modification of the anode with carbon black further increased power density, generating power densities an order of magnitude larger than those obtained at unmodified electrodes. The ability of beer brewery waste water (BBWW) to generate power at these modified surfaces yielded permissible power densities (∼40% that of reinforced clostridial media). Differences observed, in particular under agitation, are attributed to variations in nutrient content and nutrient complexity, between the two fuel substrates.
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- Date Issued: 2014
Applications of lead phthalocyanines embedded in electrospun fibers for the photoinactivation of Escherichia coli in water
- Authors: Osifeko, Olawale L , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189898 , vital:44945 , xlink:href="https://doi.org/10.1016/j.dyepig.2014.05.010"
- Description: Lead (II) pyridyloxyphthalocyanine (PbTpyPc) and its quaternized form (PbTepyPc) were synthesized and the photophysical behavior examined. Low fluorescence quantum yields (ΦF) of 0.01 and 0.02 were observed for PbTepyPc and PbTpyPc, respectively. The singlet oxygen quantum yields (ΦΔ) were 0.60 and 0.68, for PbTepyPc and PbTpyPc, respectively using DPBF as a quencher in DMF. Singlet oxygen production of the embedded sensitizers in electrospun fiber were quantified using ADMA and were found to be ΦΔ = 0.41 and ΦΔ = 0.21 for PbTepyPc and PbTpyPc, respectively. Photodynamic inactivation of Escherichia coli (E. coli) with the quaternized photosensitizer at 5 μM, totally inactivated the E. coli (with log CFU = 10 decrease). Only 0.4 log CFU decrease was obtained with PbTpyPc. The embedded non-quaternized photosensitizer (PbTpyPc) was less active on the gram negative bacteria but the quaternized photosensitizer (PbTepyPc) was effective towards inactivation of E. coli.
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- Date Issued: 2014
Argumentative and trustworthy scholars
- Authors: McKenna, Sioux , Boughey, Chrissie
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187216 , vital:44580 , xlink:href="https://doi.org/10.1080/13562517.2014.934351"
- Description: Research-intensive universities, such as the Russell Group in the UK, the Ivy League Colleges in the USA and the Sandstone Universities in Australia, enjoy particular status in the higher education landscape. They are, however, also often associated with social elitism and selectivity, and this has led to critique as higher education systems seek to widen access. This article looks at how academic staff are discursively constructed in five such institutions in South Africa through an analysis of documentation submitted as part of a national review. Three interrelated discourses are identified: a discourse of ‘staff as scholars’ whereby research is privileged over teaching, a discourse of ‘academic argumentation’ whereby a critical disposition is valued and is called upon by academics to resist development initiatives and a discourse of ‘trust’ whereby it is assumed that academics share a value system and should thus be trusted to undertake quality teaching without interference.
- Full Text:
- Date Issued: 2014
Behavior of palladium nanoparticles in the absence or presence of cobalt tetraaminophthalocyanine for the electrooxidation of hydrazine
- Authors: Maringa, Audacity , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189796 , vital:44932 , xlink:href="https://doi.org/10.1002/elan.201400028"
- Description: We report on the electrodeposition of palladium nanoparticles (PdNPs) on a glassy carbon electrode (GCE) and onto a poly-CoTAPc-GCE (CoTAPc=cobalt tetraamino phthalocyanine) surface. The electrodes are denoted as PdNPs-GCE and PdNPs/poly-CoTAPc-GCE, respectively. PdNPs/poly-CoTAPc-GCE showed the best activity for the oxidation of hydrazine at the lowest potential of −0.28 V and with the highest currents. The results were further supported by electrochemical impedance spectroscopy (EIS) which showed that there was less resistance to charge transfer for PdNPs/poly-CoTAPc-GCE compared to PdNPs-GCE. The catalytic rate constant for hydrazine oxidation was 6.12×108 cm3 mol−1 s−1 using PdNPs/poly-CoTAPc-GCE.
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- Date Issued: 2014
Book Review: Community of insecurity
- Authors: Magadla, Siphokazi
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/298606 , vital:57720 , xlink:href="https://doi.org/10.1080/02589001.2014.936174"
- Description: Laurie Nathan's Community of Insecurity is a thoughtful engagement with the ‘establishment, evolution and effectiveness of the regional security arrangements of the Southern African Development Community (SADC)’ (1). He argues that it is of ‘great significance and irony that many of the major disputes among member states have been around the orientation and strategies of peacemaking and regional security’. Nathan's empirical claims about the SADC security architecture are drawn from his ‘insider perspective’ due to his involvement in official efforts to design a common security regime in Southern Africa, which include his service as regional security advisor to the SADC Secretariat from 1992 to 1996, to the Foreign Minister of Mozambique Pascoal Mocumbi from 1994 to 1995, to the South African Minister of Defence Joe Modise and the Deputy Minister of Defence Ronnie Kasrils between 1994 and 1999 and to the Foreign Minister of Swaziland Albert Shabangu when he oversaw the SADC Organ on Politics, Defence and Security Cooperation in 1999–2000 (12–13). This ‘insider’ view has allowed him to make a compelling challenge to current theoretical debates about SADC's status as a security community, that is, a community with an affinity amongst member states that is ‘so strong that they enjoy dependable expectations of peaceful change and thus regard the prospect of war among them as inconceivable’(129). While other commentators see SADC as either a ‘nascent’, ‘embryonic’ or ‘emerging’ security community, Nathan argues forcefully that ‘this perspective is mistaken’ as SADC continues to be demonstrative of a what he describes as a ‘community of insecurity’.
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- Date Issued: 2014
Carbon nanotube-enhanced photoelectrochemical properties of metallo-octacarboxyphthalocyanines
- Authors: Mphahlele, Nonhlanhla E , Le Roux, Lukas , Jafta, Charl J , Cele, Leskev , Mathe, Mkhulu K , Nyokong, Tebello , Kobayashi, Nagao , Ozoemena, Kenneth I
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241595 , vital:50953 , xlink:href="https://doi.org/10.1007/s10853-013-7710-1"
- Description: The photoelectrochemistry of metallo-octacarboxyphthalocyanines (MOCPc, where M = Zn or Si(OH)2) integrated with MWCNTs for the development of dye-sensitized solar cells (DSSCs) is reported. The DSSC performance (obtained from the photo-chronoamperometric and photo-impedimetric data) decreased as ZnOCPc > (OH)2SiOCPc. The incorporation of the MWCNTs on the surface of the TiO2 film (MOCPc–MWCNT systems) gave higher photocurrent density than the bare MOCPc complexes. Also, from the EIS results, the MOCPc–MWCNT hybrids gave faster charge transport kinetics (approximately three times faster) compared to the bare MOCPc complexes. The electron lifetime was slightly longer (ca. 6 ms) at the ZnOCPc systems than at the (OH)2SiOCPc system (ca. 4 ms) meaning that the presence of the MWCNTs on the surface of the TiO2 film did not show any significant improvement on preventing charge recombination process.
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- Date Issued: 2014
Celebrating 30 years of Feminism and Psychology
- Authors: Macleod, Catriona I , Capdevila, Rose , Marecek, Jeanne , Braun, Virginia , Gavey, Nicola , Wilkinson, Sue
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444262 , vital:74211 , xlink:href="https://doi.org/10.1007/s11205-013-0452-2"
- Description: Feminism and Psychology (FandP) was launched in 1991 with a sense of possibility, enthusiasm and excitement as well as a sense of urgent need – to critique and reconstruct mainstream psychology (theory, research methods, and clinical practice). Thirty years have now passed since the first issue was produced. Thirty volumes with three or four issues have been published each year, thanks to the efforts of many. On the occasion of FandP’s 30th anniversary, we, the present and past editors, reflect on successes, changes and challenges in relation to the journal. We celebrate the prestigious awards accruing to the journal, its editors, and authors, and the significant contributions the journal has made to critical feminist scholarship at the interface of feminisms and psychologies. We note some of the theoretical and methodological developments and social changes witnessed over the last three decades. We highlight challenges facing feminist researchers in academia as well as international feminist publishing. We conclude that the initial enthusiasm and excitement expressed by the then editorial collective was justified. But, there is still much work to be done.
- Full Text:
- Date Issued: 2014
Challenges facing teachers in implementing alternative measures of discipline in schools: a case study of five secondary schools in the Umzimkhulu circuit of the Sisonke District in Kwazulu-Natal
- Authors: Zulu, Xolani Wycliff
- Date: 2014
- Subjects: School discipline , Secondary schools , Sisonke District -- Kwazulu-Natal, South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/11260/2393 , vital:41455
- Description: This dissertation is a report on a study that was conducted in rural schools of the Sisonke District in KwaZulu-Natal, a province of South Africa. The study covered the challenges experienced by teachers in implementing the alternative measures of discipline. The study was conducted because the researcher was the head of the disciplinary committee in the school where he was employed and he often dealt with disciplinary problems which usually occurred between the teachers, learners and SMTs. It was important to know from other schools, what problems they faced in implementing the alternative measures of discipline. The study used a qualitative research design in the form of a case study. Purposive sampling was used. The sample comprised 15 SMT members, and 20 post level 1 teachers, and the total number of participants was 35. Data was collected through observations which were followed by interviews. Qualitative methods were used to analyse data. This involved reduction and interpretation of data collected. The findings of the study highlighted the role that could be played by SMTs, teachers, parents, and the Department of Education in the smooth running of the school in dealing with the misunderstandings of alternative measures of discipline and so advance an effective work ethos. The study also illuminated the issue of negligence on the part of SMTs in enforcing the implementation of the alternative measures of discipline. There was a great need for school teachers to be well versed in the general legislation of the Department of Education so as to align themselves with the correct rules and regulations when they deal with disciplinary problems. , Thesis (MEd) -- Faculty of Humanities, Educational Management and Policy, 2014
- Full Text:
- Date Issued: 2014
Characterization of electrodes modified by one pot or step by step electro-click reaction and axial ligation of iron tetracarboxyphthalocyanine
- Authors: Maringa, Audacity , Mashazi, Philani N , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193892 , vital:45403 , xlink:href="https://doi.org/10.1016/j.electacta.2014.09.011"
- Description: The modification of the glassy carbon electrode (GCE) was carried out using two methods. The first method is simultaneous electropolymerization and electro-click followed by immersion into a solution of dimethyl formamide (DMF) containing FeTCPc. The second method is step by step whereby electropolymerization is carried out first followed by electro-click and then immersion into a DMF solution containing FeTCPc. From the electrochemical characterization, it was observed that the second route (step by step method) was the best as indicated by the ferricyanide studies (cyclic voltammetry and scanning electrochemical microscopy). In the electrooxidation of hydrazine, we obtained a potential of 0.26 V. Of interest were the detection limit of 6.4 μM and the catalytic rate constant of 2.1 × 109 cm3 mol−1 s−1. This shows that the sensor can be used for the electrooxidation of hydrazine.
- Full Text:
- Date Issued: 2014
Collection of urban tree products by households in poorer residential areas of three South African towns
- Authors: Kaoma, Humphrey , Shackleton, Charlie M
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180980 , vital:43678 , xlink:href="https://doi.org/10.1016/j.ufug.2014.02.002"
- Description: The high rates of urban in-migration and poverty common in many developing country towns potentially increases the reliance of urban populations on the direct benefits provided by trees. Yet understanding of the extent of such use and the sources of these tree products is limited. Here we report on the extent of use of urban tree products by 450 households in the poorer areas of three towns along a rainfall gradient based on household questionnaires. We considered the proportion of households making use of each of several tree products and the collection or purchasing frequency which we disaggregated by source of the product, including trees in homesteads, urban spaces, edges of towns and via purchase from traders. Most households (91%) used firewood, which was most frequently collected from the urban fringe or purchased, although one-third at times also collected firewood from trees on their home plot. All households used fruits, most commonly sourced through purchase (98%), but nearly half of whom also supplemented by harvesting fruits from their home plot. Other products used included wood for building, fencing and utensils, herbal medicines, planting material and mulch. Collection of products from urban homestead trees was highest amongst households in the informal settlements and least in the more established townships. Residents of new low-cost housing areas made extensive use of urban tree products harvested in urban spaces because they had fewer homestead trees than residents of informal areas or townships. Overall, urban residents made use of a wide array of tangible products from trees which they sourced from a variety of places, including their homestead plot. This urges that planning agencies ensure that homestead plot sizes or other urban spaces that provide tree products are large enough to support the direct needs of poorer urban residents.
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- Date Issued: 2014
Comparison of fluorophore and peroxidase labeled aptamer assays for MUC1 detection in cancer cells
- Authors: Flanagan, Shane , Limson, Janice , Fogel, Ronen
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431076 , vital:72742 , xlink:href="10.1109/BioCAS.2014.6981720"
- Description: Aptamers hold great promise for cancer diagnosis and therapy. Several biosensors incorporate aptamers as biorecognition elements for tumor markers although few evaluate their detection in a native conformation and cellular micro-environment. In this study, fluorophore and peroxidase labeled aptamer configurations were compared for the detection of MCF7 breast and SW620 colon cancer cell lines expressing the tumor marker MUC1. Fluorescence based detection showed selective binding to the cell lines relative to a nonbinding control sequence with sequence specific binding differences between MUC1 aptamers accredited to variation in the glycosylation state of expressed MUC1. The peroxidase labeled assay showed high detection sensitivity although low binding specificity was observed for the MUC1 aptamers to the cell lines. Results suggest that aptamers susceptible to non specific binding to cells may limit the applicability of enzymatic amplification to improve aptasensor sensitivity.
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- Date Issued: 2014
Comparison of the biology of geographically distinct populations of the citrus pest, Thaumatotibia leucotreta (Meyrick)(Lepidoptera: Tortricidae)
- Authors: Opoku-Debrah, John K , Hill, Martin P , Knox, Caroline M , Moore, Sean D
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/405769 , vital:70204 , xlink:href="https://hdl.handle.net/10520/EJC160246"
- Description: Baculovirus biopesticides are an important component of integrated pest management programmes worldwide. One such example is the Cryptophlebia leucotreta granulovirus (CrleGV) which is used for the control of false codling moth, Thaumatotibia (= Cryptophlebia) leucotreta (Meyrick) (Lepidoptera: Tortricidae), a pest of citrus and other crops in South Africa. A potential problem associated with constant application of viral biopesticides is the differing susceptibility to the virus observed between different geographic populations of the insect host. This could be related to a number of factors, including biological performance and fitness of the target insect population. This study compared a variety of phenotypic traits between geographically distinct T. leucotreta populations collected from the Addo, Marble Hall, Citrusdal and Nelspruit regions of South Africa, and reared under laboratory conditions for several generations. Traits including pupal mass, female fecundity, egg hatch, pupal survival, adult eclosion and developmental time were used as parameters to measure biological performance and fitness. Insects from the Citrusdal region of the Western Cape exhibited significantly lower pupal mass, female fecundity, egg hatch, pupal survival, adult eclosion and the longest duration in larval and pupal development compared to the other colonies investigated. This is the first study to report differences in the performance of laboratory reared T. leucotreta from different geographic locations, and the findings may have important implications for the application of viral biopesticides for the control of this pest in South Africa.
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- Date Issued: 2014
Conjugates of platinum nanoparticles with gallium tetra–(4-Carboxyphenyl) porphyrin and their use in photodynamic antimicrobial chemotherapy when in solution or embedded in electrospun fiber
- Authors: Managa, Muthumuni , Antunes, Edith M , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193791 , vital:45396 , xlink:href="https://doi.org/10.1016/j.poly.2014.03.050"
- Description: The conjugation of Pt nanoparticles with ClGa(III) 5,10,15,20-tetrakis-(4-carboxyphenyl) porphyrin (ClGaTCPP) showed greater antimicrobial activity against a gram positive and drug resistant bacteria Staphylococcus aureus, than when the porphyrin was used alone. ClGaTCPP and its conjugate with platinum nanoparticle was successfully electrospun into a polystyrene polymer where the diameter ranged from 10 to 22 μm. The conjugates within the fiber still showed activity towards S. aureus.
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- Date Issued: 2014