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Determining productivity, residual damage and cost of two alternative harvesting systems in pinus elliottii thinning

  • Authors: Dembure, Tigere Pasca , Spinelli, Raffaele , Ramantswana, Muedanyi
  • Date: 2018
  • Subjects: Pinus caribaea , Forests and forestry Logging Harvesting -- South Africa
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: http://hdl.handle.net/10948/22016 , vital:29813
  • Description: Pinus elliottii is the second most dominant softwood grown in the South African plantation forestry industry. It possesses desirable timber characteristics and is useful for production of solid wood products. In the silviculture of softwoods (grown for solid wood products), thinning is an important tending operation. It is necessary for stand hygiene and volume increment of residual trees through the creation of growing space. The selection of a suitable harvesting system for thinning is vital. The system of choice has to attain higher productivity, cause the least damage to residual trees and must be cost effective. From as early as 2000 the South African forestry industry witnessed a general shift towards the use of fully mechanised cut-to-length harvesting systems. This has been a result of high labour turnover, increased labour costs, increased timber demand and the effects of HIV and AIDS on forestry workers. With this recent introduction of mechanised systems, they have not been benchmarked against conventional harvesting systems. In this regard, two harvesting systems were studied side-by-side for productivity, residual damage and cost in a seventh row second thinning operation in P. elliottii stands. First thinnings generate poor financial returns since small trees are harvested and they have a relatively low financial value but have a relatively high operational cost per unit harvested. The second thinning operation is usually the thinning operation that is most likely to result in an intermediate financial return for the organisation, hence the need to benchmark these harvesting systems during the second thinning. These systems were a fully mechanised cut-to-length (CTL) and a semi-mechanised tree length (TL) system. The fully mechanised system comprised of a harvester (felling) and a forwarder (extracting) and the semi-system consisted of felling by chainsaw, tractor extraction, roadside processing by chainsaw and stacking by three-wheeled logger. Two uniform compartments planted with P. elliottii were selected for the study. A total number of 32 plots (16 plots per compartment) were marked and randomly assigned between the two treatments, each plot comprised of seven rows, with the middle row clear-cut and three rows on either side, where marked trees were selectively removed. Within each plot, the number of removal trees ranged from 80 to 105. The diameter, height and form of each removal tree were measured to determine tree volume and ultimately determine productivity. Before analysis, plot characteristics were compared to determine if conditions were equal for both treatments using the Mann-Whitney test at alpha level ˂ 0.05. There was a statistically significant difference in total operator efficiency between the two systems (p ˂ 0.0001). The fully mechanised system attained higher levels of productivity than the semi-mechanised system (15.58 m3/SMH versus 5.26 m3/SMH, for felling and 15.56 m3/SMH versus 5.29 m3/SMH, for the extraction operation). Operator productivity comparisons were restricted to the two harvester operators, and one operator achieved 16.9 m3/SMH while the other operator achieved 14.3 m3/SMH. Different operator working technique contributed to the productivity differences with one operator spending (on average) four seconds less per tree on the fell-process work element. Residual tree damage was assessed immediately after all felling and extraction had taken place. Damage size was measured as ellipse surface area. For each record of residual damage, the damage type was noted, damage position along the stem, and tree position from extraction trail. The most predominant damage type was bark peel. The motor-manual system caused five per cent damage and the fully mechanised system inflicted only three per cent damage to the residual trees. Residual tree damage from the semi-mechanised system mainly occurred at the root zone, and occurred more frequently on edge trees. The mechanised CTL system was characterised by high investment and operational costs. The mechanised system incurred 3037.75 R/SMH while the semi-mechanised system incurred 1667.10 R/SMH. The difference in total costs per year between both systems was 56.29 per cent, with the fully mechanised system being more expensive. The high capacity and the superior technology of mechanised harvesting systems may not be fully exploited in thinnings, therefore harvesting systems with lower capital costs and reasonable productivity can be competitive.
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  • Date Issued: 2018

Determining the effect of ocean proximity on residential property prices in Port Elizabeth

  • Authors: Hibbers, Vicky
  • Date: 2018
  • Subjects: Prices -- South Africa -- Port Elizabeth -- Mathematical models , Real property -- Prices -- South Africa -- Port Elizabeth Real estate management -- Prices -- South Africa -- Port Elizabeth Real property -- Valuation -- South Africa -- Port Elizabeth
  • Language: English
  • Type: Thesis , Masters , MCom
  • Identifier: http://hdl.handle.net/10948/22204 , vital:29874
  • Description: Economic contribution studies, including those from a maritime perspective, are of great interest to both governmental and non-governmental organisations, as well as researchers. This interest stems from the increased pressure on land-based resources, and it is expected that this interest in maritime economics will increase (Hosking, Lee, Kaczynsky, Hosking, du Preez and Haines, 2014). A few studies have been undertaken in order to investigate the ocean’s economic contribution in South Africa (Hosking et al., 2014). However, there are other, often overlooked, benefits that the ocean may bring to localised economies, namely its contribution to residential property markets. Over the last decade, this area of research has received considerable international attention (Rinehart and Pompe, 1994; Rush and Briggink, 2000; Taylor and Smith, 2000; Boarnet and Chalermpong, 2001; Major and Lusht, 2004; Conroy and Milosch, 2009; Scorse, Reynolds and Sackett, 2015). The studies revealed the existence of an ocean premium, which is an additional amount added to the value of a home due to it being located near the ocean. However, from a South African perspective, there is a lack of studies in this area. This study seeks to contribute to the body of knowledge by determining the effect of ocean proximity on property prices in Summerstrand, a suburb in Port Elizabeth. The hedonic price model is applied in this regard. A sample size of 104 properties was used for the study, and the various characteristics of the properties obtained from multiple sources. Most importantly, sales prices were obtained from the South African Property Transfer Guide (SAPTG). As the houses were sold in different time periods, it was necessary to adjust the prices to constant 2016 rands. The ABSA house price index was used for this, in order to account for any inflationary changes over the various periods. The results of the study revealed that proximity to the ocean had a statistically significant positive effect on adjacent residential property prices in Summerstrand, Port Elizabeth. More specifically, proximity to the ocean is valued at between R133.35 and R329.59 per meter closer to the ocean. From a policy perspective, quantifying this coastal premium in Port Elizabeth may encourage the continued conservation of marine resources within Nelson Mandela Bay. Various studies have shown the positive impact conservation has on property prices, resulting in significant premiums being attached to housing prices, even when property characteristics changed (Leeson, 2012; Chamblee, Colwell, Dehring and Depken, 2011). Economic analysis, which includes hedonic pricing, has also had an impact on the evaluation of environmental policies, with Government agencies being the first to fund studies in order to determine the effects of various externalities on housing prices. On the other hand, litigation has had an even more significant impact on policies, due to it being more tangible evidence (Palmquist and Smith, 2001). The manner in which government, and other bodies, assess and measure property values can also be improved upon. Through the separation of housing characteristics, the true value of the property can be determined. This can result in improved accuracy of property tax calculations, and a more accurate value of future developments (Gilbert, 2013). This can help ensure no unnecessary cost expenditure by both government, and property developers, especially considering the volatile nature of the housing market (Gilbert, 2013). The results of this dissertation are subject to two important qualifications. Firstly, the study does not account for the imperfect information that might be present in the market. Secondly, the relatively small sample size could limit the results.
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  • Date Issued: 2018

Developing a citizen technician based approach to suspended sediment monitoring in the Tsitsa River catchment, Eastern Cape, South Africa

  • Authors: Bannatyne, Laura Joan
  • Date: 2018
  • Subjects: Sediments (Geology) -- Management , Sediments (Geology) -- South Africa -- Eastern Cape , Watersheds -- South Africa -- Eastern Cape , Suspended sediments -- South Africa -- Eastern Cape , Suspended sediments -- Monitoring -- Citizen participation , Tsitsa River
  • Language: English
  • Type: text , Thesis , Masters , MSc
  • Identifier: http://hdl.handle.net/10962/62593 , vital:28211
  • Description: Suspended sediment (SS) in channels is spatiotemporally heterogeneous and, over the long term, is known to be moved predominantly by flood flows with return periods of ~1 - 1.5 years. Flood flows in the Tsitsa catchment (Eastern Cape Province, South Africa) are unpredictable, and display a wide range of discharges. Direct, flood-focused SS sampling at sub-catchment scale was required to provide a SS baseline against which to monitor the impact on SS of catchment rehabilitation interventions, to determine the relative contributions of sub-catchments to SS loads and yields at the site of the proposed Ntabelanga Dam wall, and to verify modelled SS baselines, loads and yields. Approaches to SS sampling relying on researcher presence and/or installed equipment to adequately monitor SS through flood flows were precluded by cost, and the physical and socioeconomic conditions in the project area. A citizen technician (CT)-based flood-focused approach to direct SS sampling was developed and implemented. It was assessed in terms of its efficiency and effectiveness, the proficiency of the laboratory analysis methods, and the accuracy of the resulting SS data. A basic laboratory protocol for SSC analysis was developed, but is not the focus of this thesis. Using basic sampling equipment and smartphone-based reporting protocols, local residents at eleven points on the Tsitsa River and its major tributaries were employed as CTs. They were paid to take water samples during daylight hours at sub-daily timestep, with the emphasis on sampling through flood flows. The method was innovative in that it opted for manual sampling against a global trend towards instrumentation. Whilst the management of CTs formed a significant project component, the CTs benefitted directly through remuneration and work experience opportunities. The sampling method was evaluated at four sites from December 2015 - May 2016. The CTs were found to have efficiently and effectively sampled SS through a range of water levels, particularly in the main Tsitsa channel. An acceptable level of proficiency and accuracy was achieved, and many flood events were successfully defined by multiple data points. The method was chiefly limited by the inability of CTs to sample overnight rises and peaks occurring as a result of afternoon thunderstorms, particularly in small tributaries. The laboratory process was responsible for some losses in proficiency and accuracy. Improved laboratory quality control was therefore recommended. The CT-based approach can be adapted to other spatial and temporal scales in other areas, and to other environmental monitoring applications.
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  • Date Issued: 2018

Developing an integrated model to improve effectiveness of asset maintenance management systems for FMCG organisations in South Africa

  • Authors: Njezula, Azola
  • Date: 2018
  • Subjects: Maintenance -- Management , Plant maintenance -- South Africa -- Management Total productive maintenance
  • Language: English
  • Type: Thesis , Masters , MBA
  • Identifier: http://hdl.handle.net/10948/22868 , vital:30113
  • Description: Maintenance has traditionally been viewed by organisations as negatively affecting profitability and productivity. It is also often viewed as fixing things when they are broken, non-value adding, unpredictable, and never a positive contributor to a company’s overall effectiveness. For this reason organisations are constantly seeking proactive maintenance strategies that will turn around this traditional view of maintenance. These strategies will also help organisations gain competitive advantage, and improve productivity and profitability. In the fast-moving consumer goods (FMCG) industry, maintenance is under increasing pressure from the regulatory bodies in terms of safety and quality regulations that are getting stringent. The pressure for FMCG organisations is to produce products that are cleaner, safer, and greener, with minimal or no consumer complaints. There is also a need for environmental sustainability, reduction in waste, and effective usage of energy, water, and materials. The maintenance team is instrumental in these reductions and in ensuring regulatory compliance. As legislated by the South African government authorities, it is compulsory for FMCG organisations to comply with regulations. These regulations are designed to safeguard consumer health and safety. The focus of the regulations is throughout the value chain of the business for transparent record keeping. The current study investigated how to improve the effectiveness of maintenance management systems for FMCG organisations. The effectiveness was compared to best maintenance management practices that literature provides. The name of the company used for the research will not be disclosed for confidentiality reasons, and it will be called ‘Selected FMCG’ for the purpose of the study. The company is a chocolate making factory based in East London. This study aims to identify the problems facing the maintenance management system within the factory. The best practices that literature provides for maintenance were used to develop an effective asset maintenance management system for Selected FMCG.
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  • Date Issued: 2018

Developing and testing the congruency of selected biological indicators and an existing tool designed to assess wetland health in agricultural settings in the KZN Midlands

  • Authors: Kubheka, Patrick Skhumbuzo
  • Date: 2018
  • Subjects: Wetland conservation -- South Africa -- KwaZulu-Natal , Wetland management -- South Africa -- KwaZulu-Natal , Wetland ecology -- South Africa -- KwaZulu-Natal , Ecosystem services -- South Africa -- KwaZulu-Natal , Environmental monitoring -- South Africa -- KwaZulu-Natal , Water quality biological assessment -- South Africa -- KwaZulu-Natal
  • Language: English
  • Type: text , Thesis , Masters , MSc
  • Identifier: http://hdl.handle.net/10962/58310 , vital:27211
  • Description: Despite the fact that wetlands have been understood to be important for a wide range of ecosystem services, wetlands continue to be degraded globally. There has been a growing need to develop biomonitoring tools that reflect the present ecological state of wetlands, but very few attempts have been made in South Africa to achieve this, and those that have attempted this have generally achieved limited success. This study was conducted to develop and test the congruency of four selected biological indicators (dragonflies, frogs, macroinveterbrates and plants) in relation to the assessment of present ecological state using an existing method in South Africa, "WET-Health". WET-Health assessments rely primarily on transformations to a wetland that result from human impacts in both the catchment and the wetland itself. Using the tool, a health score is obtained that is consistent with the Department of Water Affairs (DWA) current "present ecological state” as applied to river health assessment. The study was conducted in agricultural settings of the Midlands of KwaZulu-Natal based on 13 wetlands. The selected wetlands were scored using WET - Health and grouped in four different ecological condition classes (A, B, C and D). Physical characteristics (wetland area, mean depth), biological characteristics (species cover/abundance, presence and species richness), and chemical characteristics (ammonia, pH, sulphate, nitrogen and phosphate) were also recorded in the selected wetlands. Nineteen different species of dragonfly were recorded in this study. The study demonstrated that dragonflies are a promising bioindicator of wetland present ecological state as the dragonfly index was found to be closely correlated with WET- Health scores. Open water bodies within the selected wetlands were the focus of dragonfly sampling, as male dragonflies are territorial and they will patrol or be found around this habitat. Emergent vegetation dominated by sedges formed the focus of macroinvertebrate sampling in this study because greater numbers of macroinvertebrate families were found in this biotope in comparison to open water areas with no emergent vegetation. A total of 47 macroinvertebrate families were recorded in this study, but SASS5 scores based on macroinvetebrates showed no correlation with WET-Health scores. A total of 10 different frog species were recorded in this study. All the species were common frog species found in most parts of the country. Frog species richness and occurrence showed no correlation with WET- Health scores. A total of twenty samples of two meter radius were measured per wetland and sampled for plant species and estimation of cover-abundance of each species per sample. Over 50 different plant species were recorded in this study, and both species accumulation and species richness showed a degree of correlation with WET-Health scores. All the wetlands in class A had generally higher species accumulation rate and species richness compared to the other wetland classes. In addition to testing the congruency of four selected biological indicators with WET- Health, water quality was measured in all the wetlands. Wetlands in class A were associated with improved water quality as the water passes through the wetland. However, wetlands in class C and D did not show consistently improved water quality between the apex and the toe of these wetlands. In some cases the water quality deteriorated as it passed through wetlands in these two classes.
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  • Date Issued: 2018

Developing leadership and learner voice: a formative intervention in a Learner Representative Council in a Namibian secondary school

  • Authors: Haipa, Vistorina
  • Date: 2018
  • Subjects: School management and organization -- Namibia , Educational leadership -- Namibia , Education, Secondary -- Namibia , Student government -- Namibia , Student participation in administration -- Namibia , Student participation in administration -- Law and legislation -- Namibia , Cultural Historical Activity Theory
  • Language: English
  • Type: text , Thesis , Masters , MEd
  • Identifier: http://hdl.handle.net/10962/62188 , vital:28136
  • Description: Learner participation in leadership in Namibian schools was legislated in 2001 through the Namibian Education Act, No. 16 of 2001. This has then become a requirement for all secondary schools to establish a Learner Representative Council (LRC). However, this legislation only gives mandates to schools with grade 8-12. Despite the impetus of having a LRC in secondary schools, learner leadership and voice remains limited, given that we are 26 years into our democracy. This awakened my interest to conduct a study aimed at developing leadership and voice within the LRC in a Namibian secondary school. Additionally, this study was conducted to contribute to filling the gap in literature of Cultural Historical Activity Theory (CHAT) studies in the field of Education Leadership and Management. In this critical case orientation, the LRC were the subjects and the object of the activity was voice and leadership development within the LRC. I investigated participants’ perspectives on LRC leadership opportunities that existed in the case study school as well as factors that enabled and constrained leadership and voice development within the LRC of Omukumo (pseudonym) Secondary School in the northern part of Namibia. My study adopted a formative intervention design, using qualitative methodologies such as document analysis, observation, interviews, questionnaires and Change Laboratory Workshops. This study was framed by the second generation of CHAT. CHAT in this study was used as a methodological and analytical tool to surface the contradictions. Additionally, data were analysed by means of constructing categories and themes. Five sets of findings emerged: (1) a lack of conceptual awareness of the construct ‘learner leadership’: learner leadership was understood in terms of the LRC, (2) LRC members were not really acknowledged as equal participants in the school decision-making due to unequal power relations between the teachers and the LRC members, (3) misinterpretation of LRC policy that speak about the establishment of learners club and inadequate LRC training hindered the development of voice and leadership within the LRC, (4) the overall leadership role assigned to the LRC was to oversee the adherence of the school rules, and last (5) learner leadership and voice was still developing in the case study school. My key recommendation based on the research findings is the need for on-going LRC training at regional level; a need for large scale comparative studies between two African countries (Namibia, & South Africa) on the topic of learner leadership development and last, a need for workshops to train teachers on the implementation of national policies in schools, in particular those that speak to issues of learner voice and leadership.
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  • Date Issued: 2018

Development and assessment of a smart thermosetting intranasal hydrogel for lamotrigine

  • Authors: Melamane, Siyabonga
  • Date: 2018
  • Language: English
  • Type: text , Thesis , Masters , MSc
  • Identifier: http://hdl.handle.net/10962/62975 , vital:28349
  • Description: Expected release date-April 2020
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  • Date Issued: 2018

Development and assessment of gastroretentive sustained release captopril micro-balloons

  • Authors: Oridota, Omoyosola Omolola
  • Date: 2018
  • Language: English
  • Type: text , Thesis , Masters , MSc
  • Identifier: http://hdl.handle.net/10962/63491 , vital:28419
  • Description: Expected release date-April 2020
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  • Date Issued: 2018

Development and evaluation of a web application employing artificial neural networks to facilitate the prediction of antiretroviral drug resistance in patients infected with HIV-1 subtype B

  • Authors: Nabatanzi, Margaret
  • Date: 2018
  • Language: English
  • Type: text , Thesis , Masters , MSc
  • Identifier: http://hdl.handle.net/10962/63396 , vital:28406
  • Description: Expected release date-April 2019
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  • Date Issued: 2018

Development and optimisation of a novel Plasmodium falciparum Hsp90-Hop interaction assay

  • Authors: Wambua, Lynn
  • Date: 2018
  • Subjects: Plasmodium falciparum , Molecular chaperones , Heat shock proteins , Protein-protein interactions , Antimalarials
  • Language: English
  • Type: text , Thesis , Masters , MSc
  • Identifier: http://hdl.handle.net/10962/62626 , vital:28216
  • Description: Protein-protein interactions are involved in a range of disease processes and thus have become the focus of many drug discovery programs. Widespread drug resistance to all currently used antimalarial drugs drives the search for alternative drug targets with novel mechanisms of action that offer new therapeutic options. Molecular chaperones such as heat shock proteins facilitate protein folding, play a role in protein trafficking and prevent protein misfolding in cells under stress. Heat shock protein 90 (Hsp90) is a well-studied chaperone that has been the focus of cancer drug development with moderate success. In Plasmodium falciparum (P. falciparum), heat shock proteins are thought to play a vital role in parasite survival of the physiologically diverse habitats of the parasite lifecycle and because Hsp90 is prominently expressed in P. falciparum, the chaperone is considered a potentially ideal drug target. Hsp90 function in cells is regulated by interactions with co-chaperones, which includes Heat shock protein 70-Heat shock protein 90 organising protein (Hop). As opposed to directly inhibiting Hsp90 activity, targeting Hsp90 interaction with Hop has recently been suggested as an alternative method of Hsp90 inhibition that has not been explored in P. falciparum. The aim of this research project was to demonstrate PfHsp90 and PfHop robustly interact in vitro and to facilitate high-throughput screening of PfHsp90-PfHop inhibitors by developing and optimising a novel plate capture Hsp90-Hop interaction assay. To establish the assay, the respective domains of the proteins that mediate Hsp90-Hop interaction were used (Hsp90 C- terminal domain and Hop TPR2A domain). The human Hsp90 C-terminal domain and glutathione-S-transferase (GST) coding sequences were cloned into pET-28a(+) and murine and P. falciparum TPR2A sequences into pGEX-4T-1 plasmids to enable expression of histidine-tagged and GST fusion proteins, respectively, in Escherichia coli. The P. falciparum Hsp90 C-terminal domain sequence cloned into pET-28a(+) was supplied by GenScript. The constructs were transformed into T7 Express lysYcompetent E. coli cells and subsequent small- scale expression studies showed the recombinant proteins were expressed in a soluble form allowing for subsequent protein purification. Purification of the recombinant proteins was achieved using nickel-NTA and glutathione affinity chromatography for the His-tagged (Hsp90 C-terminal domains and GST) and GST fusion proteins (TPR2A domains), respectively. The purified proteins were used to establish and optimise mammalian and P. falciparum Hsp90- Hop interaction assays on nickel-coated plates by immobilising the His-tagged C-terminal domains on the plates and detecting the binding of the GST-TPR2A domains using a colorimetric GST enzyme assay. Z’-factor values above 0.5 were observed for both assays indicating good separation between the protein interaction signals and negative control background signals, although relatively high background signals were observed for the mammalian interaction due to non-specific binding of murine TPR2A to the plate. Designed human and P. falciparum TPR peptides were observed to be effective inhibitors of the mammalian and P. falciparum interactions, demonstrating the assay’s ability to respond to inhibitor compounds. Comparison of assay performance using GST assay kit reagents and lab- prepared reagents showed the assay was more efficient using lab-prepared reagents, however, lower GST signals were observed when comparing assay performance using a custom prepared Ni-NTA plate to a purchased Ni-NTA plate. The Hsp90-Hop interaction assays were also performed using an alternative assay format in which the GST-TPR2A fusion proteins were immobilised on glutathione-coated plates and binding of the His-tagged C-terminal domains detected with a nickel-horseradish peroxidase (HRP) conjugate and a colorimetric HRP substrate. The assay showed higher interaction signals for the P. falciparum proteins but comparatively low signals for the mammalian proteins. Z’-factor values for the assay were above 0.8 for both protein sets, suggesting this assay format is superior to the GST assay. However, further optimisation of this assay format is required. This study demonstrated direct binding of PfHsp90-PfHop in vitro and established a novel and robust PfHsp90-PfHop interaction assay format that can be used in future screening campaigns.
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  • Date Issued: 2018

Development of a computational chemistry scheme for testing the utility of synthetic bacteriochlorin in dye-sensitized solar cells

  • Authors: Kota, Ntsika
  • Date: 2018
  • Subjects: Dye-sensitized solar cells , Computational chemistry , Density functionals , Electronic excitation , Molecular orbitals , Oscillator strengths , Bacteriochlorin
  • Language: English
  • Type: text , Thesis , Masters , MSc
  • Identifier: http://hdl.handle.net/10962/62327 , vital:28155
  • Description: A computational chemistry scheme, based on density functional theory, was developed for in silico testing of a few bacteriochlorin properties relevant to dye-sensitized solar cells. These properties included electronic excitation wavelengths, molecular orbital energy levels, and oscillator strengths among others. Comparisons were made among four species, using computational proxies for electron injection quantum yield and photo-induced current production. The proxy measures for current production (frontier orbital energy level and short circuit current) made consistent, though qualitative, predictions about the ranking of the four dyes. The proxy measures for electron injection quantum yield (change in planar dipole moment and density of states) made less categorical predictions about the ranking. Overall, the scheme singled out one dye as the worst, but made no conclusive predictions about the relative ranking of the other three. There was insufficient data for comparison of the ranking predictions with experiment.
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  • Date Issued: 2018

Development of a low-cost bioprinting system for the fabrication of cell-laden sodium alginate hydrogels

  • Authors: Honiball, John Robert
  • Date: 2018
  • Subjects: Regenerative medicine , Tissue engineering , Alginates , Colloids , Three-dimensional printing
  • Language: English
  • Type: text , Thesis , Masters , MSc
  • Identifier: http://hdl.handle.net/10962/59204 , vital:27470
  • Description: Bioprinting is a rapidly expanding technology with the ability to fabricate in vitro 3D tissues in a layer-by-layer manner to ultimately produce a living tissue which physiologically resembles native in vivo tissue functionality. Unfortunately, large costs associated with commercially available bioprinters severely limit the amount of people/research groups with access to the technology. Here, we investigated the potential for modifying a commercially available RepRap Prusa iteration 3 (i3) three-dimensional (3D) printer, by replacing the traditional plastic-based print-head with various open-source syringe-housed microextrusion print-head units, such that deposition of composite bioinks consisting of cells, biopolymer scaffolds and/or biomolecules may be achieved at a relatively low cost. Using adipose-derived human mesenchymal stromal stem cells (ad-HMSC) induced for adipogenic differentiation, as well as human umbilical vein endothelial cells (HUVEC), the potential for fabricating vascularised adipose tissue was investigated. The non-toxic, inexpensive algal polysaccharide, sodium alginate, was used to test the printability of the system, as well as for investigating the functionality unmodified sodium alginate has for use as a potential bioink in adipose tissue engineering. Cell viability assays, namely WST-1 and fluorescein diacetate (FDA)/propidium iodide (PI) live/dead cell staining, revealed that ad-HMSC were viable after 7 days of culture. However, viability of HUVEC encapsulated hydrogels revealed significantly lower cell viability. Live/dead cell staining revealed that the modified printing system was able to print ad-HMSC/HUVEC co-cocultures with a large degree of cell viability after 1 day of culture. However, after 7 days of culture, the majority of cells were revealed to be dead. Furthermore, due to the lack of mechanical integrity possessed by alginate in a liquid-like state, printing sodium alginate hydrogels in air consistently resulted in deformation of printed constructs. The newly developed 3D printing technique termed freeform reversible embedding of suspended hydrogels (FRESH) was therefore investigated as a means for achieving 3D spatial control of printed hydrogels using the modified system. Printing cell-free sodium alginate hydrogels within gelatin sacrificial support baths allowed for fabricating constructs in a spatially defined manner. However, overprinting and swelling of alginate hydrogels negatively affected the overall printing accuracy. The present study aimed to pave the way for further system modifications and refinements, such that the ultimate goal of low-cost bioprinting may be achieved. Further optimisation of printing parameters, hydrogel characteristics and sterilisation techniques may allow for fabricating viable, physiologically relevant tissues using the modified system developed.
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  • Date Issued: 2018

Development of a paediatric-friendly formulation intended for the treatment of multi-drug resistant tuberculosis

  • Authors: Nkomo, Jethro
  • Date: 2018
  • Subjects: Drugs -- Dosage , Pediatrics -- Formulae, receipts, prescriptions Multidrug-resistant tuberculosis -- South Africa Primary health care -- South Africa
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: http://hdl.handle.net/10948/33660 , vital:32962
  • Description: Children suffering from multidrug-resistant tuberculosis (MDR-TB) are treated with at least four drugs a day for at least twenty-four months. Approximately 25 000 - 32 000 children worldwide become infected with MDR-TB each year, yet there is a lack of adequate paediatric MDR-TB options for child-friendly dosage forms for the treatment of the condition. The available options are limited to manipulating different dosage forms intended for adults by means of breaking the tablets or otherwise, to deliver the drugs to children. This challenge that is faced by both health care professionals and caregivers subsequently poses drug quality, efficacy, and safety concerns to children being treated for MDR-TB. The objective of this study was to formulate a paediatric-friendly dosage form for the treatment of MDR-TB in children below the age of eight years. A fixed-dose combination (FDC) in form of a dispersible-tablet that contains two core drugs used in treatment of MDR-TB; levofloxacin and pyrazinamide, was developed. Quality by design principles was employed in developing the product. The systematic procedure ensures that quality is built into the product throughout the manufacturing process. It allows for identification of the critical quality attributes and modification of critical process parameters to lie within desired ranges. Preformulation studies were conducted on the active ingredients to investigate potential interactions and compatibility. Some of the analytical techniques employed in the process included an HPLC assay method that was developed to simultaneously separate levofloxacin and pyrazinamide, differential scanning calorimetry (DSC), infrared spectroscopy (IR), thermogravimetric analysis (TGA), and powder density studies. A direct compression tableting process was selected as the method of choice for product formulation. Active ingredients were blended with the excipients and compressed using tableting equipment to successfully produce FDC fast-disintegrating tablets containing 150 mg of levofloxacin and 300 mg pyrazinamide. The product quality was analysed and optimised using mathematical and statistical techniques such as response surface methodology (RSM) and ANOVA, to meet the required standards recommended by the United States Pharmacopoeia. The FDC dispersible tablet containing levofloxacin and pyrazinamide in the potential treatment of MDR-TB in children was successfully formulated, manufactured and evaluated. The tablet dosage form passed all the relevant quality criteria that governed the scope of this study and disintegrate in approximately 37 seconds when placed in water. It is generally a sizeable challenge to manufacture fixed-dose combination drug products due to physicochemical differences of various drugs, however, with adequate resources researchers may still find a way to formulate more child-friendly dosage forms for MDR-TB. This may lead to improved drug efficacy, reduced safety risks and decreased burden on caregivers and healthcare workers who must administer the treatment.
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  • Date Issued: 2018

Digital storytelling as a teaching and learning strategy: experiences of student nurses

  • Authors: Espach, Juanita
  • Date: 2018
  • Subjects: Nursing -- Study and teaching -- South Africa , Nursing students -- South Africa Storytelling -- South Africa -- Computer network resources College teaching -- South Africa Competency-based education
  • Language: English
  • Type: Thesis , Masters , MCur
  • Identifier: http://hdl.handle.net/10948/21549 , vital:29552
  • Description: The ever changing landscape of technology influences every aspect of modern society, also education. Within recent years, technological advancements and inventive educators have transformed traditional teaching and learning strategies to innovative technology infused strategies. These strategies could potentially meet the learning style of the millennial student. One such strategy is described as digital storytelling, during which student groups create a three to five minute multimedia video, utilizing a combination of digital elements such as a narrative voice recording, music, pictures, video and animation. After creating the digital story, the end product is shared with peers. Paucity in research regarding the use of digital storytelling in the context of nursing education in the Republic of South Africa was found. Thus the aim of the study was to explore and describe the experiences of student nurses during the use of digital storytelling as a teaching and learning strategy at a private Nursing Education Institution in Port Elizabeth. The researcher conducted an exploratory, descriptive, contextual and qualitative study which utilized a connectivism framework as the paradigm. Digital storytelling was used as a teaching and learning strategy in the researcher’s own class. A convenience sampling method was therefore employed to select participants. Data was gathered through documenting observational notes during the process of utilizing digital storytelling in the classroom. After the student nurses had utilized digital storytelling, five focus group interviews with twenty four research participants were conducted, which provided data saturation. The data was transcribed and analysed utilizing Tesch’s thematic analysis method and three themes emerged from the data. The benefits of digital storytelling were voiced by the participants since digital storytelling gave them a means to express themselves and they gained new skills while collaborating with others and improving their learning. There was a negative side to it as well, during which research participants experienced negative emotions, lacked the necessary technological skills and found peer teaching an obstacle to their own learning. The participants also provided suggestions to improve the use of digital storytelling during teaching and learning. A thick description of the data with a literature control was provided. The researcher utilized the findings of this study to develop guidelines for Nurse Educators in order to optimize the use of digital storytelling as a teaching and learning strategy. Rigour and trustworthiness were ensured by utilizing Guba and Lincoln’s four criteria. In this study the researcher adhered to the ethical principles as described by the Belmont Report and paid specific attention to the application of these ethical principles in the context of conducting research on one’s own teaching practices. The limitations of this study were that data was collected from only one group of student nurses at one private NEI, after the student nurses’ utilized digital storytelling for the first time in their training. The findings of this study can be used by Nurse Educators to optimize the use of digital storytelling as a teaching and learning strategy. The recommendations of this study include the implementation of the guidelines developed for Nurse Educators.
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  • Date Issued: 2018

Discontinuous gully erosion as a mechanism of wetland formation: a case study of the Kompanjiesdrif basin, Kromrivier, Eastern Cape, South Africa

  • Authors: Lagesse, Juliette V
  • Date: 2018
  • Subjects: Arroyos -- South Africa -- Kromme River (Eastern Cape) , Arroyos -- Erosion -- South Africa -- Kromme River (Eastern Cape) , Climatic geomorphology -- South Africa -- Kromme River (Eastern Cape) , Sedimentation and deposition -- South Africa -- Kromme River (Eastern Cape) , Alluvial fans -- South Africa -- Kromme River (Eastern Cape) , Wetland ecology -- South Africa -- Kromme River (Eastern Cape) , Rhizophoraceae , Palmiet (Prionium serratum)
  • Language: English
  • Type: text , Thesis , Masters , MSc
  • Identifier: http://hdl.handle.net/10962/60540 , vital:27791
  • Description: The Kompanjiesdrif basin is an unchannelled valley bottom palmiet wetland located near the headwaters of the Kromrivier in the Eastern Cape of South Africa. The wetland itself is underlain by Bokkeveld shales with the bordering mountain ranges comprising more resistant Table Mountain Group quarzitic sandstones. The valley is relatively planar and broad in form over a width of approximately 200 m. None of the existing controls that are considered to lead to valley widening and longitudinal slope reduction are immediately apparent. The basin lies on the Post Africa II erosion surface; with no evidence of a resistant lithology which might act as a local base level, limiting rates of vertical erosion and inducing lateral planing in upstream reaches via a meandering channel. The possible role of sagging of the basin due to long term deep chemical weathering of bedrock is discounted as the lithologies in the basin are sedimentary in origin and thus not susceptible to chemical weathering. The degree to which climate and sea level changes affected rates of incision and subsequent slope reduction is unclear, although their potential influence should be acknowledged. This study examined the geomorphic dynamics as discerned from the sedimentary record and morphology of the wetland basin, which provide a snapshot into the long-term processes which lowered the longitudinal slope and widened this valley. Coring within the wetland to depths of 1 - 3.3 m revealed that the sedimentary fill generally comprised an upward fining sequence, with sand or fine sand at the base, grading into silt and clay and organic material in the upper sections of cores. Occasional instances of multiple fine sand layers were observed in a few of the cores. An increase in the organic content of material from the north to the south side of the wetland and the occurrence of multiple thin layers of sand in the stratigraphy, highlighted the role of the northern tributary alluvial fans in influencing valley form. Sediment from north bank alluvial fans seem to periodically, partially impound the wetland basin. Surveyed transects across the wetland basin along with subsurface coring to the depth to refusal, illustrated a localised increase in longitudinal slope downstream of the nodes of tributary alluvial fan deposits, which impinge on the trunk stream basin. Coupled with the presence of deep, drowned, trench-like features (up to 8 m deep) beneath floating mats of palmiet, which were predominantly free of sedimentary fill and found opposite tributary alluvial fans; confirmed that the northern tributaries play a major role in the structure and geomorphic dynamics of the basin. The trench-like features appeared to be remnants of deep, narrow, discontinuous gullies. Dating of sediment from the base of these features (460-7040 BP) confirmed that they were formed prior to European settlement in the area. Therefore, it is suggested that the localised increase in longitudinal slope, caused by sediment deposition on the alluvial fans, transgresses a geomorphic threshold slope and that gully erosion is thus initiated. The process of repeated gully erosion leads to planing of bedrock and longitudinal slope reduction. Gully erosion forms an integral component of a cycle of deposition and incision referred to as “cut-and-fill”. During each iteration of the cycle of cutting and filling, gullies form in novel locations leading to gradual valley widening. Over geological time scales, the planing of bedrock and resultant valley widening creates a broad planar valley with a very low longitudinal slope; producing conditions suitable for unchannelled valley bottom wetland formation.
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  • Date Issued: 2018

Discovery and validation of a CD4 binding aptamer through Crossover SELEX towards the preliminary development of a point-of-care aptasensor for rapid CD4+ T-cell counting

  • Authors: Fellows, Tamika
  • Date: 2018
  • Subjects: Uncatalogued
  • Language: English
  • Type: text , Thesis , Masters , MSc
  • Identifier: http://hdl.handle.net/10962/63527 , vital:28431
  • Description: Expected release date-April 2020
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  • Date Issued: 2018

Discrepancy in conventional microscopic manual differential counts of band neutrophils among microscopists

  • Authors: Godson-Katchew, Chesna Terry-Lee
  • Date: 2018
  • Subjects: Neutrophils , Hematology Medical statistics -- Research
  • Language: English
  • Type: Thesis , Masters , MHSc
  • Identifier: http://hdl.handle.net/10948/30127 , vital:30830
  • Description: The interpretation of the band neutrophil count on manual differential counts performed amongst microscopists can vary greatly. The band neutrophil is an immature granulocyte, maturing towards a segmented neutrophil. There are varying degrees of misconception of the band neutrophil identification, as the band neutrophil closely resembles the maturing segmented neutrophil. Although there are guidelines for the identification of band neutrophils, many laboratories incorporate their own “standard” as to what a band neutrophil should look like. Even when a standard exists for the identification of band neutrophils, many microscopists still have difficulty identifying these cells, making it difficult to accurately perform, interpret and report a manual differential count. Due to the controversy it is thus necessary to identify whether the problem lies with the identification of the band neutrophil itself, or the individual microscopist’s perception of differentiation between the band neutrophil and a maturing segmented neutrophil. The purpose of this study was to establish the accuracy by which microscopists distinguish band neutrophils from mature segmented neutrophils, the extent of discrepancies in the band neutrophil count amongst microscopists, to establish whether microscopists required re-training and to establish meaningful recommendations for microscopists to aid in the accurate identification of band neutrophils. The researcher thus made use of a self-administered picture diagram, distributed among microscopists to assess the accuracy of the band neutrophil counts prior to training. Participants counted an average of 61.47% neutrophils and 38.53% band neutrophils. Coefficient of variation (CV) for neutrophils and band neutrophils were calculated and yielded a CV of 22.48 and 35.87 respectively. Due to the high CV calculated, suggesting a greater level of dispersion around the mean, the researcher investigated individual responses from the picture-diagram. With the findings of the individual picture-diagram results, the researcher developed an impression that there was a large variation in counts for both neutrophils and band cells. Training was then given to participants arranged by the researcher, for accurate band neutrophil identification. Following training a second survey was conducted in order to assess the variation in counts among microscopists. 1 The peripheral blood smear was then provided and used to perform a manual differential count by conventional light microscopy, in order to compare results. Similarly, results obtained by the microscopists was compared to the verified manual differential count performed by a Haematologist; to improve the accuracy of results reported routinely. With the findings of the individual manual differential count results the researcher observed, that there was indeed a discrepancy in the manual differential counts performed by microscopists.
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  • Date Issued: 2018

Discrimination and dismissal based on age

  • Authors: Hlohlolo, Sephiri
  • Date: 2018
  • Subjects: Age discrimination in employment -- South Africa , Employees -- Dismissal of -- South Africa
  • Language: English
  • Type: Thesis , Masters , LLM
  • Identifier: http://hdl.handle.net/10948/30309 , vital:30929
  • Description: The purpose of this treatise is to discuss discrimination and dismissal based on age in the workplace. When doing this, specific focus will be on the provisions of section 187(2)(b) of the Labour Relations Act and its fairness when it comes to normal or agreed retirement age for persons employed. Section 187(2)(b) sets out certain justifications on which an employer can rely when it comes to dismissals based on age. South Africa (SA) is a constitutional state and the Constitution is the supreme law. What this means is that any national legislation promulgated must not be in conflict with the Constitution. On the contrary, national legislation must enable the constitutional imperatives. Reference to the Constitution of SA will be made, more so, the equality and fairness provisions. In the process of doing so, a probe into whether section 187(2)(b) as a constitutional enabler, will pass the constitutional muster, will also be looked into. Not all discrimination is unfair when it comes to the SA Labour Law. Provision for fair discrimination has been provided for and as a result, the treatise will also look at the concept of unfair discrimination and how it has been tested by the Courts. A further discussion will outline what is meant by discrimination and dismissal based on age, and whether such a dismissal is in fact a dismissal, and whether within the requirements of the LRA, such a dismissal or termination of employment contract, is in fact, fair. The history of the development of the concept of discrimination in SA will be addressed, and so is a comparative study on foreign law. While foreign jurisprudence is cardinal, a focus on the current SA case law will be done in order to evaluate how discrimination and dismissal based on age are dealt with. Lastly, a critical analysis of sub section 187(2)(b) of the LRA in relation to subsection 187(2)(a) will be looked at, as well.
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  • Date Issued: 2018

Distribution of virulence determinants in Plesiomonas shigelloides and Vibrio species isolated from selected hospital wastewater effluents in the Eastern Cape Province, South Africa

  • Authors: Mashudu, Mavhungu
  • Date: 2018
  • Subjects: Vibrio
  • Language: English
  • Type: Thesis , Masters , MSc (Microbiology)
  • Identifier: http://hdl.handle.net/10353/14505 , vital:39996
  • Description: Plesiomonas shigelloides and some Vibrio species are amongst the bacteria species classified into the emerging pathogenic bacteria grouping, and they portend increasing virulence and high resistance to some of the most potent antimicrobial agents used as most important and critical lines of defence against pathogenic infectious agents. Hospital wastewater has attracted significant attention as a pool for the regurgitation of pathogens into the environment which eventually becomes a problem to public health. It has been variously reported that hospital wastewater critically serves also as a puddle for microbial genetic interaction with outcomes including the development of resistance to antimicrobial agents among other pathogenic traits. And, in the same vein, exchanges and gene recombination may have been leading to the emergence of virulence determinants not previously known owing to the capacity of hospital wastewater to encompass a vast diversity of pathogenic bacteria and antimicrobial agents at the same material time. Hence, this research aimed at the evaluation of the prevalence of virulence and antibiotic resistance in Plesiomonas shigelloides and some human pathogenic Vibrio species isolated from selected hospital wastewater in the Eastern Cape Province of South Africa. Wastewater samples were collected at two weeks intervals throughout three months sampling duration from hospital wastewater facility in the Eastern Cape Province. The wastewater samples were from the secondary hospital and, tertiary hospital along with Limbede community wastewater facilities based in the Eastern Cape Province of South Africa. The wastewater samples were aseptically screened for the presence of presumptive Plesiomonas shigelloides and selected Vibrio species using the culture-based method. The identity of the presumptive Plesiomonas shigelloides and Vibrio species (Vibrio cholerae, V. fluvialis, V. parahaemolyticus, and V. vulnificus) isolates were confirmed using species specific primers. After that, the presence 14 of virulence determinants and the antimicrobial susceptibility profiles of the positive strains as well as the antimicrobial resistance factors were all determined. The distribution of the presumptive isolates was as follows; 322 Plesiomans shigelloides and 378 Vibrio species respectively. However, upon molecular confirmation studies, 85 out of 322; 26% of the total presumptive isolates, were confirmed as positive for Plesiomans shigelloides and, on the other hand, from the 378 presumptive Vibrio species, 71% (270) was as positive to Vibrio genus, and upon speciation of the positive isolates; 27% (73) was confirmed as Vibrio cholerae, 9% (24) as Vibrio parahaemolyticus, 4% (12) as Vibrio vulnificus and 3% (8) as Vibrio fluvialis. The remaining 57% (153) which was unaccounted for may belong to other Vibrio species not included in this studies. Various virulence determinants were shown to be present in the Vibrio species identified and the degree varied in line with the species. P. shigelloides showed high levels of resistance to impregnated antibiotics (18 different types). The antibiogram characteristics showed P. shigelloides to possess 100% resistance to Ciprofloxacin, Nalidixic acid, Trimethoprim, Ampicillin, Penicillin, Tetracycline, Doxycycline, Erythromycin, and Cephalothin. These findings are of crucial importance to public health and the science of infectology as it gives insight into the role of the hospital wastewater as a puddle for the recombination of antibiotic resistance determinants and virulence emergence in bacteria. On the strength of the finding of this research, it is essential to indicate that there is a need for an immediate review of hospital wastewater disposal process. Some form of treatment or pretreatment of the hospital wastewater is required before discharge into municipal wastewater treatment facilities. And, perhaps, continuous monitoring of hospital wastewater to reduce the risk posed to public health.
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  • Date Issued: 2018

Donor-acceptor effects on the optical limiting properties of BODIPY dyes

  • Authors: Hlatshwayo, Zweli Thabiso
  • Date: 2018
  • Subjects: Dyes and dyeing -- Chemistry , Photosensitizing compounds -- Therapeutic use , Cancer -- Photochemotherapy , Upconversion nanoparticles (UCNPs)
  • Language: English
  • Type: text , Thesis , Masters , MSc
  • Identifier: http://hdl.handle.net/10962/63368 , vital:28397
  • Description: The main objectives of the research described in this thesis were firstly to synthesize and characterize a series of structurally related BODIPY dyes that are potentially suitable for use in applications, secondly to conjugate a carboxylic acid substituted BODIPY dye to amine-functionalized upconversion nanoparticles (UCNPs) through an amide bond to enable singlet oxygen production upon irradiation at 978 nm in the biological window for tissue penetration for biomedical applications, and thirdly to compare the nonlinear optical (NLO) properties of various BODIPY dyes to determine whether push-pull effects enhance their utility for optical limiting (OL) applications. Halogenated BODIPY cores with high singlet oxygen quantum yields were prepared, which absorb in the green portion of the visible region and making it difficult to treat deeper skin tumors in the context of photodynamic therapy (PDT) applications. UCNPs generally absorb in the near-infrared (NIR) region (978 nm), and this is advantageous because, this is where absorption by water, cells and tissues is minimized. NaYF4: Yb/Er/Gd UCNPs were synthesized, amine functionalized and successfully conjugated to a halogenated carboxylic acid functionalized BODIPY. This allowed for favorable Förster resonance energy transfer (FRET) since one of the emission wavelengths of the NaYF4: Yb/Er/Gd UCNPs overlaps with the main absorption band of the BODIPY at 540 nm. The conjugate was irradiated at 978 nm, but instability of the BODIPY dye was observed, which made singlet oxygen quantum yield determination impossible. An enhanced singlet oxygen quantum yield value was observed upon irradiation of the conjugate at 540 nm, suggesting that further studies of this system are warranted. The OL properties of BODIPY cores and dyes, which are π-extended at the 3,5-positions with styryl groups, were studied in a series of different organic solvents at 532 nm by using the z-scan technique on a nanosecond timescale. Many of the dyes were used to compare the effects of introducing electron donor and acceptor groups on the OL properties of the dyes. The dipole moments of these dyes were found to correlate with the OL response. The OL results indicate that BODIPY dyes with push-pull properties, which are π-extended at the 3,5-positions with styryl groups, can be considered as viable candidates for use in OL applications. The studies sought to establish the effect of ESA in the triplet manifold as compared to the singlet manifold in as far as the OL response is concerned. The most promising dyes were embedded in polystyrene thin films, and this was found to significantly enhance their OL properties.
  • Full Text:
  • Date Issued: 2018
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