Assessing land degradation and the effectiveness of calcrete bontveld rehabilitation in a grassridge PPC cement mining area using multi-sensor remotely sensed data and machine learning techniques
- Authors: Mpisane, Khanyisa
- Date: 2023-12
- Subjects: Land degradation -- South Africa , Environmental degradation , Mines and mineral resources -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62527 , vital:72821
- Description: This study uses multi-temporal remote sensing data to spatially visualise and quantify land degradation due to mining as well as Calcrete Bontveld rehabilitation at the Grassridge PPC Cement mine, Gqeberha formerly known as Port Elizabeth in the Eastern Cape, South Africa. Botanical field data is also used to verify the suasses of rehabilitation in the area. SPOT-6 and Landsat multi-spectral images were compared, and Support Vector Machine and Random Forest algorithms were used for classification in order to determine which yields more accurate results for a limestone mine. Support Vector Machine analysis using SPOT-6 images yielded the best results. This was due to the high spatial resolution of SPOT-6 compared to Landsat and Support Vector Machine classifier was able to classify images with fewer training points compared to Random Forest. The spatio-temporal land cover change at the mine was then determined between the years 2000, 2015 and 2020. Land cover classification is useful for monitoring land degradation and, in this case, was able to show the extent of rehabilitation success. For the year 2020, a 17% area was rehabilitated; however, the algorithm could not distinguish between unmined Calcrete Bontveld matrix and rehabilitation sites that were older than five years. The performed change detection also showed that 29.50% of unmined Calcrete Bontveld matrix had changed to “mature rehabilitation” (rehabilitation sites older than five years). Again, for this percentage in some areas the algorithm could not distinguish between the unmined Calcrete Bontveld matrix and rehabilitation sites that were older than five years due to high similarities between the two land cover types. Area changes of the different land cover classes could also be used to demonstrate how rehabilitation areas have matured over time and lead to the conclusion that most of the Calcrete Bontveld which was mined, has over the years been successfully rehabilitated. Vegetation analysis was conducted to further validate the rehabilitation success of Calcrete Bontveld matrix. Multivariant Detrended Correspondent Analysis showed that rehabilitation sites which were younger than five years (2–year-old rehabilitation plots that were sampled) had great dissimilarity to the natural unmined Calcrete Bontveld matrix and that rehabilitation sites older than five years, in this case 16–years older, had high similarity and resemblance to natural unmined Calcrete Bontveld matrix and therefore could be considered as being mature. This was a more definitive assessment as it considers all aspects of the vegetation. Species cover and species richness also showed that Calcrete Bontveld matrix rehabilitation sites which have been rehabilitated for more than 5 years had greater similarity to natural unmined vegetation compared to areas that have been rehabilitated for less than five years. This study, therefore, demonstrates that due to the high similarity between mature rehabilitation sites and unmined Calcrete Bontveld, rehabilitation has been successful. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2023
- Full Text:
- Date Issued: 2023-12
Assessing the effectiveness of smart solutions on potable water in rural areas within Ngqushwa local municipality
- Authors: Fodo, Portia Noluthando
- Date: 2023-12
- Subjects: Potable water -- tap water , water infrastructure
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/63298 , vital:73245
- Description: Providing potable water is a critical reposition towards achieving the Sustainable Development Goal (SDG) 6, to ensure the availability and sustainable management of water and sanitation for all. In addition, the use of smart solutions facilitates towards guaranteeing smart cities aligned with SDG11 which is aimed at making cities and human settlements inclusive, secure, resilient and viable. Access to potable water is a challenging issue in most rural areas as these areas were affected by the Apartheid regime where services were distributed according to the colour of the skin. In rural areas where many black people reside, the challenge of service delivery still exists. Ngqushwa Municipality is faced with several trials in the management of water, including water scarcity, lack of water infrastructure as well as illegal water connections. Despite more than 25 years of democracy, rural dwellers in Ngqushwa Municipality still suffer from a deficiency of access to potable water, which results in other health problems, such as Cholera. This study was aimed at assessing the role of smart solutions in the effective management of potable water in rural areas in Ngqushwa Local Municipality. The objectives to be achieved include identification of the policies that support the implementation of smart solutions in the provision of potable water in Ngqushwa Local Municipality, as well as determining the opportunities and challenges associated with smart solutions in the delivery of potable water. Moreover, identifying the existing difficulties affecting the execution of smart solutions in the delivery of potable water, along with developing recommendations on how smart solutions can effectively be put into operation in rural areas to control water. A qualitative research approach was applied as the chosen research methodology most appropriate to achieving the objectives of the research study. Data was collected using secondary sources and was analysed using thematic content analysis. The study revealed that opportunities available include accurate billing, smart metering and information availability. Furthermore, the obstacles included capacity constraints, cost factors and resistance to change. The investigation recommended, inter alia, that the municipality should accurately train its employees on matters relating to change management and establish effective debt controlling mechanisms to enhance water supervision in rural areas. , Thesis (MA) -- Faculty of Humanities, 2023
- Full Text:
- Date Issued: 2023-12
Assessing the effectiveness of the planning, utilisation and implementation of the electronic human resource management strategy: a case of the department of home affairs in the Eastern Cape
- Authors: Dyan, Margaret Nombuyiselo
- Date: 2023-12
- Subjects: Personnel management , Home Affairs -- Eastern Cape
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/63287 , vital:73244
- Description: This study assessed the effectiveness of planning, implementing and utilising the electronic human resource management (e-HRM) strategy within the King William’s Town (KWT) Department of Home Affairs (DHA) in the Eastern Cape Province (EC) of South Africa (SA). E-HRM emerged because of the advent of technology. Many organisations use information technology to optimise the performance of both the employees and the organisation. Thus, this technology has been incorporated into organisations’ human resource functions, taking advantage of the latest technology to deliver an online real-time human resource management (HRM) solution. Therefore, this study sought to assess the e-HRM strategy's effectiveness within the KWT DHA. The technology acceptance model was adopted as a theoretical framework for the study to explain the adoption of the e-HRM strategy. A qualitative research approach using a case study research design was used for this study. Non-probability purposive sampling and convenience sampling were used to identify participants for the study. These participants provided the information needed to answer the research questions. The data was collected using in-depth interviews with the participants. The data was then analysed using thematic analysis following Braun and Clarke’s guidelines (2006). The study results revealed that implementing the e-HRM strategy within KWT DHA proves to be effective and efficient. The strategy’s implementation has been associated with improved performance of the KWT DHA in the Eastern Cape. It also saves time and ensures that HR information is accessed easily. The study also found barriers to the planning, implementation and utilisation of the e-HRM strategy, including a lack of skills and knowledge and resource constraints. The study also found that the current e-HRM policies are not fully functional. The study recommends continuous personnel training regarding the strategy, maximising the use of the e-HRM strategy and addressing the resource challenges. , Thesis (MA) -- Faculty of Humanities, 2023
- Full Text:
- Date Issued: 2023-12
Assessing the effects of fish stock management on Cape gannet foraging behaviour in South Africa
- Authors: Strydom, Zanri , Grémillet, David , Pichegru, Lorien
- Date: 2023-12
- Subjects: Gannets -- South Africa , Birds of prey -- Behavior -- South Africa , Fish stock assessment
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/62622 , vital:72887
- Description: Seabirds are one of the most threatened groups of birds under both marine and terrestrial pressures. Among seabirds, the Cape gannet Morus capensis is a southern African endemic species facing several pressures of anthropogenic origin, including competition with industrial fisheries on small pelagic fish stocks. Cape gannets, being a long-lived species that is sensitive to environmental changes, are sentinels of change in oceanic environments granting it important to understand which factors influence their foraging behaviour and breeding outputs. For example, factors like age can result in a loss of physical capabilities which can lead to behavioral compensation and subsequent changes in chick provisioning rates and amounts. With the current fisheries management the fish stocks are continually decreasing, indicating the importance of an updated fine-scale assessment on the spatiotemporal overlap between foraging gannets and fisheries. The first objective of this thesis was to determine the influence of adult Cape gannets’ age and sex on their foraging characteristics and energy expenditure during foraging. I equipped chick-rearing Cape gannets of known age and sex with a 3D accelerometer and GPS device. Foraging effort (trip duration, foraging path and maximum distance to the nest) did not differ between sexes nor with age in Cape gannets. Both sexes rested less on the water with age. Aging females also spent more time in flight than males. The age- and sexual differences in energy expenditure prevalent in our study might reflect niche and/or risk partitioning strategies to ensure adequate provisioning to the chick. The second objective of this thesis was to determine the influence of fisheries catch rates, sardine and anchovy biomass, and adult foraging effort on chick growth rates in Cape gannets, using a long-term dataset collected between 2005 and 2020 on Malgas Island. I equipped chick-rearing adults with a GPS device and I weighed the chicks for between 3 to 6 increments to calculate the average daily mass increment. Of all the variables, foraging trip duration was the main determinant of daily growth rates, with chicks benefitting from parents’ shorter foraging trip durations. Chicks tended to grow slower when fisheries catch of sardine and anchovy were higher, possibly an effect of competition with fisheries. Chicks also grew faster when fish biomass was higher. This long-term monitoring demonstrated the possible effect of food competition between Cape gannets and fisheries, with negative impacts on gannet fitness as determined via chick growth rates. The third objective of this thesis was to determine the influence of both the biomass and fisheries catch rates of sardine and anchovy on Cape gannet foraging effort at a spatial and temporal scale. This was achieved by equipping a total of 668 chick-rearing Cape gannets with a GPS device. With an increase in fisheries catch there was an increase in the birds’ foraging effort. To reduce competition between the gannets and fisheries, the gannets’ core foraging areas seldomly overlapped with the fisheries catch locations, at the cost of the gannets’ increased foraging effort. One method to halt the Cape gannet population decline would be to conserve the fish resources close to the breeding colonies. This would reduce the birds’ foraging whereby increasing their fitness. Safeguarding small pelagic fish to ensure the perseverance of the remaining Benguela seabird populations, would lead to preserving the Benguela marine ecosystem as a whole. My study provided new insight into effects of fish stock management on Cape gannet foraging behaviour in South Africa, and the need for adequate management to ensure population persistence. , Thesis (PhD) -- Faculty of Science, School of Environmental Sciences, 2023
- Full Text:
- Date Issued: 2023-12
Assessing the effects of materials management practices on performance of locomotive manufacturing firms in Gauteng province
- Authors: Setino, Rebecca
- Date: 2023-12
- Subjects: Materials management , Industrial procurement , Business logistics -- South Africa -- Gauteng
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/65935 , vital:74288
- Description: The study assessed the effects of materials management practices (materials planning, procurement, availability, handling, and delivery) on the performance of rail rolling stock and locomotive manufacturing firms in Gauteng Province. The study also investigated the causes of delays in supply of materials in the rail rolling stock and locomotive manufacturing industry in Gauteng. The research design employed was both descriptive and explanatory, using a quantitative research approach in which online surveys were conducted on a sample of 200 respondents from the rolling stock manufacturing firms in Gauteng. Descriptive statistics performed through SPSS 27 and SEM performed through AMOS 26 were used for data analysis. The findings of the study revealed that materials management practises were implemented in the rail rolling stock and locomotive manufacturing industry. According to the results, materials availability and materials handling have positive and statistically significant effects on the performance of rail manufacturing firms in Gauteng Province. However, materials planning, procurement and delivery practices have no significant effect on the performance of rail manufacturing firms in Gauteng Province. Therefore, the results reveal that firm performance is driven by materials availability and materials handling. In addition, late delivery of materials to the production line was found to be the main cause of project delays. The study thus offered a contrasting perspective to the general findings that show materials management practices to be a significant contributor to manufacturing firm performance. However, the study confirms the importance of materials handling and availability as a predictor of performance in manufacturing firms. , Thesis (MCom) -- Faculty of Business and Economic Sciences, School of Management Sciences, 2023
- Full Text:
- Date Issued: 2023-12
Assessment of knowledge, attitudes, practices and the prevalence of intestinal parasites in Sarah Baartman District, Eastern Cape
- Authors: Mrwebi, Sisanda
- Date: 2023-12
- Subjects: Intestinal parasites , Knowledge Attitudes and Practices , transmitted helminths
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62924 , vital:73070
- Description: ntestinal parasites also known as parasitic worms are one of the common water, soil and feacal transmitted infections of public importance in the world. This study evaluated the Knowledge, Attitudes and Practices (KAP) of public workers comprising EPWP and CWP general workers on intestinal parasites in a selected municipality in the study area . Additionally, using secondary data, the researcher established the prevalence of intestinal parasites in Sarah Baartman District Municipality (SBDM) from 2012 to 2020. Method: The study made use of a quantitative, cross-sectional research design resembling a study by S.D. Hambury .A structured questionnaire, closed-ended, telephonically-administered questionnaire was used to collect data from 160 Expanded Public Works Programme (EPWP) and Community Work Programme (CWP) general workers. Data on the prevalence was obtained from the SBDM National Health Laboratory Service (NHLS). Data was analysed using both inferential and descriptive statistics using SPSS software version 16.1, inferential statistics tests used were Chi2 square tests and p-value tests. Descriptive statistic tests used included frequency distributions, percentage, cumulative percent, and valid percent. Results: The participants’ overall awareness, attitudes and practices of the study were poor, 64.4% of the study participants had the correct knowledge about intestinal parasite infections. The age of study participants and who the participants thought was at risk of being infected by intestinal parasites had a non significant relationship (p>0.05). Gender and the responses to who is at risk of getting infected with intestinal parasites had a statistically significant (p<0.05) relationship. Intestinal parasite prevalence from 2012 to 2020 in SBDM was 46.37% which means it was close to half of the sampled population. Males had the highest prevalence as compared to females, with a prevalence of 53.1% xvi in males and 46.9% in females. The highest disease infection was found between ages one and six years. Conclusion: The researcher concluded that the overall awareness, attitudes and practices on intestinal parasites in SBDM were poor. The intestinal parasites present in SBDM were Cytoisospora belli (35.4%) and Giardia lamblia (35.4%), Ascaris lumbricoides (17.7%), Trichuris trichiura (3%), and Taenia species (2%). The study also revealed that the prevalence of intestinal parasites was low from 2012 to 2020. Recommendations were made with an emphasis on education to increase disease prevention and control awareness. , Thesis (Ma) -- Faculty of Health Science, 2023
- Full Text:
- Date Issued: 2023-12
Association of antiretroviral therapy adherence and Development of cardiovascular desease risk
- Authors: Fihla, Qhayiya Mteto
- Date: 2023-12
- Language: English
- Type: Masters theses , text
- Identifier: http://hdl.handle.net/11260/12894 , vital:76176
- Description: IAntiretroviral therapy (ART) is the standard treatment for human immunodeficiency virus (HIV). The treatment reduces HIV load to low level, relegating the disease from an acute infection to a chronic condition. Of late, there have been increased reports associating ART with increased cardiovascular disease (CVD) risk, further reducing the possibility of complete positive health outcomes for people living with HIV (PLWH). Poor adherence to the ART has been implicated in the development of some CVD risk factors but levels of adherence is not well known in the Eastern Cape. Thus, this study was designed to determine the level of ART adherence and associated cardiovascular risk factors. A cross-sectional study of a 100 participants was conducted to determine ART adherence and prevalence CVD risk factors in Mthatha. Both Male and female participants above 18 years of age were selected and ART adherence was determined using the adherence in chronic diseases scale (ACDS). The lipid profile, anthropometric measurements, and clinical parameters were used to determine CVD risk factors. Regression models were fitted to determine the association between adhrence and CVD risk factors in PLWH. All statistical analysis was performed using the statistical package for social sciences (SPSS) version 28, and the statistical significance was set at The average adherence rate was found to be 90.35% population of PLWH sampled, and 30% participants were found to have the optimum adherence rate ≥95%, which considered be adequate to effect viral progression. The prevalence of CVD risk factors was found to be 97%, with 46% of the participants having CVD. Although it was not statistically significant, the regression analyses indicated that non-adherent patients were more likely to report presence of CVD risk factors. This suggests that sub-optimal adherence to ART may be a contributing factor towards CVD risk development in patients on ART. It is possible that the results are clinically significant but there is a need to collect more data to increase the statistical power of the study , Thesis (Masters) -- Faculty of Medicine and Health Sciences, 2023
- Full Text:
- Date Issued: 2023-12
Case-based research on the fedup model for self-help housing
- Authors: Qumbisa, Nolwazi
- Date: 2023-12
- Subjects: Community participation , Human settlements , Informal settlements
- Language: English
- Type: doctoral's theses , text
- Identifier: http://hdl.handle.net/10948/62199 , vital:72007
- Description: In South Africa, the government subsidises the building of starter homes to meet the demand for housing for people with lower incomes. However, it is necessary for the state to revise its efforts to meet the demand for housing in the country. Self-help housing is a model that can be used as an alternative to state housing subsidies. The present research study investigates the essential aspects of sustainable self-help housing in the central region of South Africa. The present study aimed to address the central research topic by eliciting responses from participants: How can self-help provision become sustainable in the central region of South Africa? In response to the question, an effective self-help housing support model was developed, the aim of which is to outline how self-help housing projects could be improved. The literature findings demonstrate the potential of this model as a viable alternative to the existing housing delivery mechanism in South Africa. This assertion is supported by a study of self-help housing trajectories and an examination of relevant South African housing policies. However, there has been a lack of emphasis on the simplification of current models to accommodate the needs of implementers, government entities, and beneficiaries of self-help housing initiatives. This study aimed to address the highlighted gaps by utilising a qualitative methodology and drawing upon the data obtained. The data collection techniques included semi-structured interviews, structured observations, and focus-group discussions. A total of 25 semi-structured interviews were conducted with key stakeholders in human settlements, while the focus-group discussions involved 50 participants. A total of 5 focus group discussions were conducted with each group consisting of 10 participants. Moreover, the researcher conducted a document analysis, observations, and questionnaire survey. The data collected were analysed thematically. The results revealed that there are still challenges with implementing self-help housing. Moreover, the results are attributed mainly to a mismatch of the roles and responsibilities and not understanding the Enhanced People’s Housing Process (EPHP) policy. The principal contribution of the thesis is that housing policies, programmes and sector plans must encourage beneficiaries to play an active role. This study found that weak or unclear project vi specifications lead to contractor misunderstandings or discrepancies in housing project implementation, resulting in poor-quality work or delays. The conventional contractor-driven housing-delivery model also has issues like poor construction, corruption and mismanagement, profit-driven contractors, high contractor rates, project delays/incomplete projects, illegal occupation of incomplete projects, riots and disputes, ineffective project specifications, and beneficiary disengagement. In this study, it is demonstrated how a positive social impact on housing could be the outcome of an improved self-help approach. Consequently, the research suggests the adoption of an effective self-help housing support model, which may effectively address the challenges posed by informal settlements while enhancing the execution of self-help housing projects. The model has the potential to make contemporary contributions to the public housing policy model in South Africa. This study contributes to the broader discourse on sustainable housing alternatives, providing insights into the various obstacles, potential advantages, and recommended strategies within the realm of selfhelp housing. The study's qualitative approach facilitated a comprehensive examination of the lived experiences and viewpoints of diverse stakeholders. This yielded valuable insights that can inform policymakers, practitioners, and communities in their efforts to improve the sustainability of self-help housing solutions in the central region of South Africa. , Thesis (PhD) -- Engineering, Built Environment and Technology, 2023
- Full Text:
- Date Issued: 2023-12
Characterization of the coastal Aquifer of Gqeberha, South Africa : Developing a conceptual understanding
- Authors: Vandala, Bamanye
- Date: 2023-12
- Subjects: Aquifers -- South Africa -- Port Elizabeth , Groundwater ecology , Hydrogeology
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62710 , vital:72932
- Description: The aquifer systems in Gqeberha are poorly understood due to a lack of groundwater studies within the area, and this is particularly the case for the coastal aquifer of Gqeberha. Amidst the water crisis the city is currently facing, groundwater has become crucial, with over 1000 boreholes reportedly drilled in the coastal area, most of which are residential. This has resulted in the need to conduct more groundwater studies in the area and in Nelson Mandela Bay. This study presents a detailed hydrogeological characterization of the coastal aquifer of Gqeberha. This was achieved through the use of different techniques, which include field mapping, geophysics, hydrochemistry, and pumping test analysis. The work was done on the coastal seeps of the Algoa Group Formation and the fractured aquifer of the Peninsula Formation. The results through mapping indicated an abundance of folds, faults, and fractures which all have implications for groundwater flow. The majority of fractures are striking in the NE-SW and NW-SE directions. The pumping test analysis also indicated fractal flow with significant matrix flow resulting in a dual porosity system up to at least 200m in depth. The transmissivity and storativity values range from 6.78 – 44.5 m2/day and 0.0172 – 0.0325, respectively. This is highly dependent on the fracture interconnectivity, which varies across the area and is higher at shallow depths, as suggested by the geophysical profiles. Geophysical profiles indicate that the contact between the Algoa Group Formations and the Peninsula Formation results in coastal seeps due to the difference in hydraulic conductivities. The hydrochemical analysis suggests that the seeps generally have Na-Cl and Ca-Mg-Cl water types. The groundwater in the eastern area has a Ca-HCO3 water type, and the groundwater in the western region has a Ca-Mg-Cl water type, with the Chelsea-Noordhoek Fault system separating the two groundwater signatures. Groundwater at greater depths has a Na-Cl water type with higher TDS values. The chemical signatures seen are due to external factors, which include sea sprays, anthropogenic activities, rock-water processes, and possibly connate water in the Peninsula Formation aquifer. The findings of this study offer valuable insights into the present conditions of the aquifer in Gqeberha. This research serves as a foundational study that can provide a baseline for future hydrogeological investigations in the area. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2023
- Full Text:
- Date Issued: 2023-12
Chemical analysis and biological activities of crude extracts and essential oil of selected medicinal plants from the Eastern Cape, South Africa, and Volta Region of Ghana
- Authors: Agbo, Irene Adzo
- Date: 2023-12
- Subjects: Medicinal plants , Lantana camara , Peptic ulcer -- Treatment , Traditional medicine - South Africa -- Eastern Cape , Traditional medicine -- Ghana
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62431 , vital:72728
- Description: Lantana camara and Khaya grandifoliola extracts are among many plants found traditionally effective for the treatment of wounds and ulcers. This study assessed the phytochemical content, isolation and identification of single compounds from methanol and ethyl acetate extracts of Lantana camara and Khaya grandifoliola. Further, the bioactivity testing including antioxidant, antimicrobial and cytoxicity of the extracts was done to confirm the wound healing potential discovered by the traditional healers. Materials and methods: Extraction was done successively using maceration method with 100 % ethyl acetate and 100 % methanol with a biomass-to-solvent ratio of 1:3 (w/v) to obtain L. camara ethyl acetate extracts of berry (ELB), flower (ELF) and leaf (ELL) and methanol extracts of MLB, MLF, MLL and K. grandifoliola ethyl acetate extracts of leaf (EKL), root (EKR) and stem bark (EKSB) and methanol extracts of MKL, MKR, MKSB respectively. L. camara leaf essential oil (EO) was extracted using the hydro-distillation method with a Clevenger apparatus. Total phytochemical content was assessed for each extract using spectrophotometric methods and a calibration curve of standards: bromocresol green method with atropine; Folin–Ciocalteu colorimetric method with gallic acid, aluminium chloride colorimetric method with quercetin and concentrated sulphuric acid chloroform with linalool for total alkaloid, phenolic, flavonoid and terpenoid contents respectively. Single compound isolation and purification was conducted using chromatographic techniques. Elucidation of single compounds was done using spectrometric method, high resolution- mass spectrometry, and one and two-dimensional (1D and 2D)-NMR. Stereochemistry of each compound was confirmed using electronic circular dichroism spectra. A Crystalline compound was identified by single crystal X-ray diffraction using CuKα-radiation. In vitro bioactivities were assessed with methods such as 3-[4,5-dimethylthiazole-2-yl]-2,5-diphenyltetrazolium bromide, free radical scavenging activity of 1,1-diphenyl-2-picrylhydrazyl, inhibitory effect on nitric oxide production in lipopolysaccharide-activated RAW 264.7 macrophages, and 96-well plate micro dilution for cytotoxicity, ant-inflammatory and antimicrobial activity testing. Results: Methanol extracts of both plants retained high phytochemical concentrations of all the phytoconstituents investigated compared with the ethyl acetate extracts which retained lower concentrations. The results of the L. camara methanol extracts include; total alkaloid content (TAC) (2.05±0.18, 1.87±1.54 and 2.60±1.10 mg AEQ/100 mg); total phenolic content (TPC) (14.05±4.04, 34.59±3.01 and 18.58±1.87 mg GAEQ/100 mg); the total flavonoid content(TFC) of flower (12.45±1.87, 20.41±2.69 and mg QEQ/100 mg); total terpenoids (TTC) (20.74±2.34, 20.74±2.34 and 15.97±1.19 mg LIN EQ/100mg) of MLB, MLF and MLL respectively. Whereas that of the K. grandifoliola methanol extracts include; TAC (7.32±0.14,8.49±0.34, 10.67±0.22 mg AEQ/100 mg); TPC (37.49±1.40, 44.41±0.69, 53.57±1.50 mgGAEQ/100 mg); TFC (6.54±0.55, 9.58±0.89 and 10.26±0.92 mg QEQ/100 mg); TTC(10.16±1.41, 35.78±2.14 and 23.45±1.76 mg LIN EQ/100mg) of MKL, MKR and MKSB respectively. The major components of essential oil, out of the 71 constituents identified include Davanone D (32.91 %), Caryophyllene (5.07 %), Nerolidol 2 (3.56 %) and GermacreneD (3.13 %). Compounds 3.47 was isolated from the methanol extract of L. camara flowers. This compound is reported for the first time from the L. camara flower extract. Two compounds, compounds 4.23, and 4.26, were isolated from the methanol extract of K. grandifoliola roots, compound 4.22 was isolated from the ethyl acetate root extract while compounds 4.24 and 4.25 were isolated from the ethyl acetate stem bark extract as isomers in a mixture. Compounds 4.22 and 4.23 are reported from K. grandifoliola root for the first time. The isolated compounds (compounds 3.47 and 4.23) were nontoxic to the Vero cell line and this may contribute to possible stimulation of cell proliferation, promoting wound healing. Cytotoxicity describes extract virulence to Vero cell line. MLF and ELB were found nontoxic even at the highest concentration of 200 μg/mL. The MKSB and MKR, as well as the EKSB were nontoxic. Antioxidant activity results, described by the percentage inhibition in the DPPH assay, showed that MLF and MKSB had the highest antioxidant activities compared with the ascorbic acid standard, with IC50 of 38.68±5.09 and 37.03±11.95 μg/mL for L. camara and K. grandifoliola respectively. ELB exhibited a significant anti-inflammatory activity inhibiting NO• radical generation in the LPS-stimulated RAW 264.7 macrophages at concentration ranging from 50 and 100 μg/mL. EKSB and MKR showed significant anti-inflammatory activity at 100 and 200 μg/ml respectively. ELL and ELF demonstrated potent growth inhibition against S. pyogenes with an MIC value ≤ 0.125 mg/mL, while the MICs of the ELB and MLL were 0.5 mg/mL and 2 mg/mL respectively. MKSB and MKR and EKSB extract exhibited an effective growth inhibition against S. aureus with MIC of 1 mg/mL. The growth of S. pyogenes was supressed by both ethyl acetate and methanol extracts of all plant parts tested with MIC ranging from 0.25–2 mg/mL. Conclusion: The potent bioactivity shown in the results of the cytotoxicity, antioxidant activity, anti-inflammatory and antimicrobial activity testing, and the nontoxic singlecompounds of L. camara and K. grandifoliola extracts led to the conclusion that the two plants had wound healing potential. The study therefore confirmed their traditional uses for treatment of wounds. , Thesis (PhD) -- Faculty of Science, School of Biomolecular and Chemical Sciences, 2023
- Full Text:
- Date Issued: 2023-12
Creating a value proposition in the optometry industry: perceptions of customers
- Authors: Mmamogobo, Maleage Jacob
- Date: 2023-12
- Subjects: Optometry--Economic aspects , Optometry--Practice , Consumer behavior -- South Africa , Corporate image -- Management
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/65782 , vital:74237
- Description: The highly competitive environment in the optometry healthcare industry, the over-serviced urban market and the cost of keeping businesses operating with little knowledge of how a profitable business operates lead most independent business owners to employ inappropriate strategies to manage situations that arise, and the optometry industry, particularly standalone practices, are particularly vulnerable to these challenges. As a result, creating a value proposition for customers has become a common approach to operations and ensuring service providers’ survival in new and existing practices. Therefore, the limitations under which service providers operate need to be investigated to determine which competencies are lacking. The study aimed to create a value proposition in the optometry industry in South Africa by exploring optometry customers’ perceptions. Through a qualitative research approach a total of 17 telephone interviews and eight mask-to-mask interviews were conducted with participants (five per chosen service provider from all nine provinces). The participants were drawn from all service providers’ current customers, including those whom in the past three months used the services or products, purchased an optical frame temple or full pair of spectacles, underwent an eye examination, and others. The qualitative data analysis employed content and thematic analyses, focusing on key elements such as the importance of creating a value proposition, developing a value proposition process, and the challenges associated with its creation. The five building blocks for creating a value proposition are visibility, service and product, price and value, reputation management and communication. This study’s findings will assist individual service providers to evaluate themselves against customers’ expectations and benefit customers and researchers. The main recommendations are 24-hour online access to a website, quality of services or products, full standard optometry service, affordable health care products or services, a short turnaround time for complete products, and acquired management skills to grow and generate sales. , Thesis (PhD) -- Faculty of Business and Economic Sciences, School of Management Sciences, 2023
- Full Text:
- Date Issued: 2023-12
Current harmonic compensation of nonlinear loads in a three phase, four wire system
- Authors: Mtakati, Sibulele Morgen
- Date: 2023-12
- Subjects: Harmonics (Electric waves) , Electric power system stability , Electric power -- Conservation
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/66574 , vital:75608
- Description: Nonlinear loads, in low voltage distribution networks, inject current harmonics which affect the quality of supply voltages. In this work, the power usage of a university student residential complex was logged over a four day period for analysis of harmonic currents injected by nonlinear loads. Student residents use nonlinear loads such as lighting, televisions, computer power supplies, and other household appliances. The harmonic analysis was performed on the quality of voltages in the university’s distribution network, the level of current distortion in the load current and the contribution of triplen harmonics to the neutral current. Standards such as the NRS048-2 (2007), IEEE-519 (2014) and IEC61000-3-2 (2009) are helpful in regulating harmonic levels in the distribution network, however, they cannot guarantee good quality supply. This work further investigates two methods of current harmonic cancellation, i.e. a shunt passive and an active current harmonic cancellation technique. A passive power filter was designed, built, and evaluated for a given nonlinear load to provide selective filtering of the dominant current harmonics. A four branch, shunt, passive filter was considered in this work for implementation in a three phase four wire distribution network due to its attractive possibility to be tuned to two different harmonic components with a minimum number of passive elements. While passive filters may be inexpensive, they suffer from several disadvantages, such as providing fixed compensation, performance that is source impedance dependent, has an inherent risk of system resonance and detuning due to ageing and component variation. To overcome the disadvantages of passive filters, a shunt connected active power filter was designed, built and evaluated to provide adjustable, wide bandwidth and dynamic correction to nonlinear loads for the compensation of harmonic currents, reactive power, and neutral currents. The controller used was an indirect FFT-based technique with a second order generalized integrator (SOGI) filter for voltage synchronization. It was digitally implemented in an FPGA programmed in VHDL to allow for fast parallel processing of input variables. , Thesis (M.Eng) -- Faculty of Engineering, the Built Environment, and Technology, School of Engineering, 2023
- Full Text:
- Date Issued: 2023-12
Current harmonic compensation of nonlinear loads in a three phase, four wire system
- Authors: Mtakati, Sibulele Morgen
- Date: 2023-12
- Subjects: Electric utilities -- Quality control , Electric power systems , Electric power system stability
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/66581 , vital:75607
- Description: Nonlinear loads, in low voltage distribution networks, inject current harmonics which affect the quality of supply voltages. In this work, the power usage of a university student residential complex was logged over a four day period for analysis of harmonic currents injected by nonlinear loads. Student residents use nonlinear loads such as lighting, televisions, computer power supplies, and other household appliances. The harmonic analysis was performed on the quality of voltages in the university’s distribution network, the level of current distortion in the load current and the contribution of triplen harmonics to the neutral current. Standards such as the NRS048-2 (2007), IEEE-519 (2014) and IEC61000-3-2 (2009) are helpful in regulating harmonic levels in the distribution network, however, they cannot guarantee good quality supply. This work further investigates two methods of current harmonic cancellation, i.e. a shunt passive and an active current harmonic cancellation technique. A passive power filter was designed, built, and evaluated for a given nonlinear load to provide selective filtering of the dominant current harmonics. A four branch, shunt, passive filter was considered in this work for implementation in a three phase four wire distribution network due to its attractive possibility to be tuned to two different harmonic components with a minimum number of passive elements. While passive filters may be inexpensive, they suffer from several disadvantages, such as providing fixed compensation, performance that is source impedance dependent, has an inherent risk of system resonance and detuning due to ageing and component variation. To overcome the disadvantages of passive filters, a shunt connected active power filter was designed, built and evaluated to provide adjustable, wide bandwidth and dynamic correction to nonlinear loads for the compensation of harmonic currents, reactive power, and neutral currents. The controller used was an indirect FFT-based technique with a second order generalized integrator (SOGI) filter for voltage synchronization. It was digitally implemented in an FPGA programmed in VHDL to allow for fast parallel processing of input variables. , Thesis (MEng) -- Faculty of Engineering, the Built Environment, and Technology, School of Engineering, 2023
- Full Text:
- Date Issued: 2023-12
Dietary assessment of Cape Gannets (Morus capensis) and African Penguins (Spheniscus demersus) in Algoa Bay using molecular scatology
- Authors: Bowmaker - Falconer, Kezia , Von Der Heyden, Sophie
- Date: 2023-12
- Subjects: Gannets , Gannets -- Food , Sea birds -- South Africa -- Bird Island, Algoa Bay.
- Language: English
- Type: Master's theses
- Identifier: http://hdl.handle.net/10948/62420 , vital:72675
- Description: Seabirds are important marine sentinels, providing valuable information about ecosystem health and condition. Dietary studies of seabirds can inform on ecosystem functioning through identifying the condition and changes occurring in their surrounding environment. Dietary studies are also crucial as they can identify threats that seabirds face. Until recently, the diets of southern African endemic and Endangered Cape Gannets Morus capensis and African Penguins Spheniscus demersus were solely investigated through stomach content analyses, which allows for the identification and quantification of prey remains. To overcome some of the limitations associated with stomach content analysis, stable isotope and fatty acid analyses were proposed. However, these methods still require bird handling and thus impose some stress on the birds. DNA metabarcoding of faecal matter shows promise as a completely noninvasive method for seabird dietary studies. This thesis first examined whether DNA metabarcoding could be used to determine the diet of Cape Gannet and African Penguin breeding in Algoa Bay, South Africa. Then, this method was used to investigate the influence of intrinsic (both seabird species) and extrinsic (African Penguins) factors on the diet of the two seabird species. For the first data chapter, stomach content samples and faecal matter were collected concurrently from breeding Cape Gannets and African Penguins on Bird Island. DNA was successfully extracted from most faecal matter samples and the primers (18S_SSU, 16S_Fish) used for group, taxa and fish prey identification allowed amplification of prey DNA for both study species. A similar piscivorous diet was determined by both dietary methods for Cape Gannets with Sardine Sardinops sagax and Atlantic Saury Scomberesox saurus dominating the diet. Sardine also dominated the African Penguin diet in both dietary methods. In addition, DNA metabarcoding in African Penguins revealed a more diverse diet compared to the one determined by stomach content analysis. This was likely due to the limitations on the allowed number of stomach content samples to be collected for that Endangered species. Non-invasive DNA metabarcoding of faecal matter was then used to investigate whether the diet varied with breeding stages (incubation, chick-rearing) and age classes (chick-rearing adults, chicks) in both seabird species, but also breeding colonies (Algoa Bay: Bird Island, St Croix Island) in African Penguins. DNA metabarcoding revealed that breeding stages influenced the diet of Cape Gannets and African Penguins on Bird Island where prey species diversity was greater for incubating adults. On the contrary, the diet of incubating and chick-rearing penguins on St Croix Island was similar. When comparing the diet of African Penguins between Bird Island and St Croix Island, there was an increased overlap in diet composition between incubating and chick-rearing adults on St Croix Island when compared to Bird Island. Importantly, DNA metabarcoding indicated an increase in fishery interactions in Algoa Bay, particularly for Cape Gannets and the hake Merluccius spp. fishery, where the contribution of hake to chick-rearing adults and chick diet was considerably greater than incubating adult diet. In this study, I showed that DNA metabarcoding of faecal matter provides an opportunity for non-invasive dietary studies in two southern African endemic and Endangered seabird species. Incorporating non-invasive methods as a complement to other dietary methods for monitoring seabird trophic ecology is crucial when considering the worsening status of several seabird species. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2023
- Full Text:
- Date Issued: 2023-12
Eco-leadership determinants necessary for effective sustainability implementation
- Authors: May,Jodé
- Date: 2023-12
- Subjects: Retail trade -- Management , Leadership -- South Africa , Sustainability
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/65683 , vital:74228
- Description: Sustainability is regarded globally as one of the key focus areas for organisations and requires also considering environmental and social performance in addition to economic performance. Eco-leadership is required to ensure operations impact society and the environment in a positive manner, in particular in the retail sector as customers have become conscious of their purchases being produced sustainably. The main objective of this study was thus to explore eco-leadership determinants necessary for sustainability implementation in retail organisations. The research was aimed at expanding knowledge about how retailers can implement or improve their sustainability status by following an eco-leadership approach. A literature review was conducted on what leadership in organisations entailed and how it can be described in terms of leaders’ characteristics, work practices and decisions. In addition a review on, leader qualities and leadership styles in general and of change leaders such as eco-leaders, sustainability strategies from both an environmental and socially responsible view in general and of the retail sector, was provided. The study followed a qualitative research approach using purposive sampling to identify the 11 participants from across the provinces in South Africa and retail product categories comprising of two hard-line retailers, five soft goods and consumables retailers, three FMCG retailers and one art retailer. A semi-structured interview guide was utilised to gather primary data using face-to-face, telephonic and email interviews. Content and constant comparative analysis was used to analyse the data. It appears that retailers ascribe eco-leadership in relation to resource management-, being people centred and practising sustainability leadership. All retailers seem to demonstrate their commitment to eco-leadership and serve society. Their sustainability status is publicised via digital and print media or visually displayed in-store. They practise eco-leadership as it is beneficial for their reputation or to ensure business continuity. Retailers use innovation and incorporate eco-leadership into their business models and have further plans to improve their sustainability. , Thesis (PhD) -- Faculty of Business and Economic Sciences, School of Management Sciences, 2023
- Full Text:
- Date Issued: 2023-12
Effects of annealing on the structural and optical properties of nanostructured TiO2
- Authors: Talla, Assane , Urgessa, Zelalem
- Date: 2023-12
- Subjects: Titanium dioxide , Nanostructured materials , Nanotubes
- Language: English
- Type: Doctorial theses , text
- Identifier: http://hdl.handle.net/10948/62655 , vital:72907
- Description: In this thesis, the structural, morphological and optical properties of titanium dioxide (TiO2) are investigated. Titanium dioxide (TiO2) nanotubes are prepared by anodic oxidation of titanium foil. The as-anodised samples are thermally annealed at various temperatures in nitrogen, air, oxygen and vacuum. The purpose is to study how the annealing conditions affect the properties of the nanostructures, including the anatase to rutile phase transformation. In all annealing atmospheres, except in vacuum, the dominant phase is found to be anatase when annealing is performed up to 600 oC. Above 700 oC the rutile phase becomes dominant. The anatase phase is stable above 600 oC in vacuum and does not evolve significantly up to 900 oC. The morphologies of the tubes tend to deteriorate with increased annealing temperature, in nitrogen, air and oxygen atmospheres, due to sintering effects. However, the integrity of the nanotubes is maintained up to 900 oC in vacuum. The photoluminescence (PL) spectra suggest mainly the presence of oxygen vacancies and self-trapped excitons, with respective emission bands around 2.5 eV and 2.3 eV. The results show that both the annealing temperature and atmosphere strongly influence the crystalline and optical properties of the TiO2 nanotubes. In addition, the phase transformation from anatase to rutile for samples annealed in an oxygen-rich environment is investigated in detail. Complementary structural information obtained from transmission electron microscopy and Raman analysis for oxygen-annealed samples reveals that the nucleation of the rutile phase starts from the titanium substrate and then propagates along the tubes. The results provide suitable annealing conditions to control the phase content and morphology of anodic TiO2 nanotubes. The PL characteristics of bulk crystalline anatase TiO2, namely virgin and hydrogen-annealed at 600 oC for 1 h, are studied. The low temperature PL spectra at 5.5 K shows near band edge (NBE) emissions with two dominant lines ascribed to shallow donor bound exciton and possibly free to bound recombination. The two main transitions are assisted by optical phononmodes. Temperature-dependent PL measurements performed on these anatase crystals reveal that the donor bound exciton is stable below 90 K. Hydrogen trapped in oxygen vacancies is proposed to be the shallow donor. In addition, two activation processes are involved for the thermal quenching of donor bound excitons. The total activation energy is found to correlate well with the localisation energy of the bound exciton. Site-selective PL spectra obtained from anodic TiO2 tubes reveals that the luminescence of the nanostructures depends on the morphology. The result shows unusual near-band edge emission (NBE) for these structures, which is rarely observed in indirect band gap TiO2. , Thesis (PhD) -- Faculty of Science, School of Biomolecular and Chemical Sciences, 2023
- Full Text:
- Date Issued: 2023-12
Effects of fire on architecture and composition of canopy shrubs in subtropical dune thicket of the southeastern Cape Floristic Region
- Authors: Strydom, Tiaan , Grobler, Adriaan
- Date: 2023-12
- Subjects: Plant ecology -- Research , Plant communities -- South Africa , Browsing (Animal behavior)
- Language: English
- Type: Doctorial theses , text
- Identifier: http://hdl.handle.net/10948/62632 , vital:72899
- Description: Disturbance, such as fire and megaherbivory, is a pervasive phenomenon globally and has different effects on the flora and vegetation of different ecosystems. The Cape Floristic Region (CFR) of South Africa includes the distinctive Subtropical Thicket biome, which occurs as interrupted blocks that are not exposed to fire, but also as mosaics with the fire-prone vegetation of the Fynbos biome, especially on coastal dunes where thicket species are exposed to fire. Subtropical Dune Thicket (hereafter thicket) thus co-occurs with Fynbos, capable of supporting intense fires that can lead to thicket shrub defoliation and mortality. Thicket also experiences disturbance from meso- and megaherbivores that causes defoliation and mortality of shrubs. The aim of this study was to investigate the resilience of thicket shrub species to varying disturbance levels from fire and browsing to understand what drives thicket persistence in a fire-prone landscape. Firstly, I established the architectural traits of thicket species in long unburnt and post-fire contexts and investigated the relationships between these traits and the survival, resprouting ability and persistence of thicket shrubs. In mature thicket, I identified three distinct architectural guilds, namely hedge formers, lateral spreaders, and vertical growers. In post-fire thicket I identified three resprouting architectures, namely weak resprouters, moderate resprouters and strong resprouters. There was no strong relationship between the unburnt and post-fire resprouting architectures. Secondly, I compared thicket species and architectural composition in patches of landscape that experience different levels of fire exposure to assess the potential effect of fire frequency on determining thicket structure. I recognised three thicket vegetation units, each with a distinct structure and each corresponding to the level of fire exposure in the landscape. The first unit, forest-thicket, is exposed to low levels of fire frequency (> 100 years) and harbours forest species, many of which were vertical growers. The second unit, thicket, is exposed to moderate levels of fire frequency (50-100 years) and is dominated by lateral spreaders. The last unit, fynbos-thicket, is exposed to high levels of fire frequency (10-50 years) and here hedge-forming shrubs dominate the canopy cover. Forest-thicket and fynbos-thicket had a diverse set of shrub species with many being restricted to their respective vegetation type, whereas thicket had a lower diversity with no unique shrub species. , Thesis (DPhil) -- Faculty of Science, School of Natural Resource Management, 2023
- Full Text:
- Date Issued: 2023-12
Effects of selected natural flavonoids on an optimized insulin resistance induction model on myotubes and hepatocytes in vitro
- Authors: Van de Venter, Ruben
- Date: 2023-12
- Subjects: Flavonoid , Insulin resistance , Myotubes and hepatocytes
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/63049 , vital:73085
- Description: Introduction: As the third largest life-threatening non-communicable disease, further research to improve T2DM treatment remains pivotal. The approved insulin sensitizing agents, metformin and thiazolidinediones, although effective, have an array of adverse effects. This leads to the growing need for safer insulin sensitizing agents. Aims: To induce insulin resistance, an insulin resistance induction (IRI) model consisting of palmitic acid (PA), fructose, and dexamethasone (DEX), was optimized. The model was utilized to compare the insulin sensitizing efficacy of chrysin, apigenin, luteolin, and quercetin. The most effective flavonoid was extrapolated based on the hydroxylation hypothesis and relevant SAR. The flavonoid was combined with metformin to evaluate potential insulin sensitizing synergism. Methods: C3A hepatocytes and L6 myotubes were exposed to the IRI models: IR1, IR2, and OIR, for 24 and 48h. Morphological features indicative of insulin resistance were monitored through high-content analysis (HCA). Thereafter, cells were exposed to OIR and concurrently treated with the selected flavonoids. Cytotoxicity, oxidative stress (OS), mitochondrial content, mitochondrial membrane potential (MMP), and lipid accumulation, were once again evaluated through HCA. Subsequently, quercetin was combined with metformin (QM); insulin resistant conditions established through OIR exposure, and QM administered as prophylaxis. The efficacy of QM was determined through changes in phosphorylated-Akt, glucose uptake, and gluconeogenesis. Results: IR1 and IR2 demonstrated excessive potency, whereas OIR consistently generated insulin resistant C3A/L6 cells by increasing OS (↑14%/20%), lipid accumulation (0.7-fold/1.5-fold), and decreasing MMP (↓4%/6%). Of the selected flavonoids, quercetin was most effective at ameliorating each of these parameters. Furthermore, QM demonstrated potential insulin sensitizing synergism, as it improved Akt phosphorylation (Thr308: ↑31%/↑17%; Ser473: ↑29%), glucose uptake (↑10%/ 5%), and suppressed hepatic gluconeogenesis (15↓%) more effectively compared to monotherapy. Conclusions: OIR is an effective model for the induction of complete early-stage insulin resistance in myotubes and hepatocytes. Quercetin demonstrates exceptional antidiabetic activity due its unique expression of hydroxyl groups. Lastly, QM, comparative to monotherapy, improves insulin sensitivity with enhanced efficacy. , Thesis (Ma) -- Faculty of Health Science, 2023
- Full Text:
- Date Issued: 2023-12
Effects of selected natural flavonoids on an optimized insulin resistance model in myotubes and hepatocytes in vitro
- Authors: van de Venter, Ruben
- Date: 2023-12
- Subjects: Flavonoids , Pharmaceutical chemistry , Insulin resistance
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/69648 , vital:78003
- Description: As the third largest life-threatening non-communicable disease, further research to improve T2DM treatment remains pivotal. The approved insulin sensitizing agents, metformin and thiazolidinediones, although effective, have an array of adverse effects. This leads to the growing need for safer insulin sensitizing agents.To induce insulin resistance, an insulin resistance induction (IRI) model consisting of palmitic acid (PA), fructose, and dexamethasone (DEX), was optimized. The model was utilized to compare the insulin sensitizing efficacy of chrysin, apigenin, luteolin, and quercetin. The most effective flavonoid was extrapolated based on the hydroxylation hypothesis and relevant SAR. The flavonoid was combined with metformin to evaluate potential insulin sensitizing synergism. C3A hepatocytes and L6 myotubes were exposed to the IRI models: IR1, IR2, and OIR, for 24 and 48h. Morphological features indicative of insulin resistance were monitored through high-content analysis (HCA). Thereafter, cells were exposed to OIR and concurrently treated with the selected flavonoids. Cytotoxicity, oxidative stress (OS), mitochondrial content, mitochondrial membrane potential (MMP), and lipid accumulation, were once again evaluated through HCA. Subsequently, quercetin was combined with metformin (QM); insulin resistant conditions established through OIR exposure, and QM administered as prophylaxis. The efficacy of QM was determined through changes in phosphorylated-Akt, glucose uptake, and gluconeogenesis. Results: IR1 and IR2 demonstrated excessive potency, whereas OIR consistently generated insulin resistant C3A/L6 cells by increasing OS (↑14%/20%), lipid accumulation (0.7-fold/1.5-fold), and decreasing MMP (↓4%/6%). Of the selected flavonoids, quercetin was most effective at ameliorating each of these parameters. Furthermore, QM demonstrated potential insulin sensitizing synergism, as it improved Akt phosphorylation (Thr308: ↑31%/↑17%; Ser473: ↑29%), glucose uptake (↑10%/ 5%), and suppressed hepatic gluconeogenesis (15↓%) more effectively compared to monotherapy. Conclusions: OIR is an effective model for the induction of complete early-stage insulin resistance in myotubes and hepatocytes. Quercetin demonstrates exceptional antidiabetic activity due its unique expression of hydroxyl groups. Lastly, QM, comparative to monotherapy, improves insulin sensitivity with enhanced efficacy. , Thesis (MPharm) -- Faculty of Health Sciences, School of Clinical Care & Medicinal Sciences, 2023
- Full Text:
- Date Issued: 2023-12
Enhancing the optimal use of the properties for revenue generation at the National Department of Public Works and Infrastructure
- Authors: Twala, Zolile Donald Linda
- Date: 2023-12
- Subjects: Buildings -- Maintenance and repair , Buildings -- Maintenance , Public works -- South Africa , Infrastructure (Economics) -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/66068 , vital:74329
- Description: Literature on property management revealed that it became a challenge in many countries to manage and maintain properties, especially in the public sector. Concerning public infrastructure, research has confirmed that even in the most developed states, such as Canada and the United States of America (USA), the maintenance of public properties and related services was in danger due to fewer funds being budgeted for maintenance during their life cycle (Kaganova & Telgarsky, 2018). It was noted that there needed to be more studies conducted in South Africa under public infrastructure. This study aimed to explore how the NDPWI could improve the optimal use of properties under its custodianship to maximise revenue generation by carrying out the identified critical success factors from the property managers (internal) and client departments (external). Trying to find a well-maintained property creates more chances for the client departments or tenants to occupy the property for a more extended period while delivering their service to its clients and the NDPWI maximising the revenue generation. “The research applied a literature review and other sources, such as internal or media reports, as a background to discover meaning-making of insights from the property manager’s experiences, which were associated with their perceptions of property management challenges”. This research applied a qualitative research approach. Qualitative content was analysed, utilising a mixture of a deductive and inductive approach. The main reason for utilising both deductive and inductive approaches is that the researcher tried to understand and develop the theory around the NDPWI low-income generation utilising state properties to their optimal use and find out if all properties were well maintained and could, which allowed the NDPWI to maximise income generation. Five conclusions emerged from the findings of this study on insight from twenty-five (25) property managers who have been in their role for a minimum of five (5) years. The proof to substantiate these conclusions came directly from insights shared by the twenty-five (25) participants from their experience in property management. Conclusions were linked to the theories and reports that informed this study. Firstly, this study revealed that the majority of the participants agreed that the role of leadership in property management was critical for giving strategic direction within the organisation, ensuring that there were clearly defined roles and responsibilities, and ensuring there were no contradictions and confusion among the staff while executing their functions. Adequate talent was recruited, but skills were required to be strengthened. Secondly, the study revealed that the non-maintenance of state buildings contributed negatively to the client departments when executing their constitutional mandate efficiently and effectively in a safe environment. Poor building conditions were revealed as among the issues that the client departments needed to be occupying and optimally utilising; instead, they relied on leased inn properties from the private sector. Thirdly, the study revealed that the client relationship and quality of service they received from the NDPWI needed to be improved to ensure that clients were prioritised on their needs and expectations. NDPWI was taking too long to respond to the instruction of the client departments, and it was frustrating the client departments leading to some client departments proposing to devolve the power of the NDPWI to assist them. Fourthly, accessibility of the state properties was not as good as it was supposed to be, as the client departments would need the properties in specific areas, they needed to offer their services, and they could not get such properties under the NDPWI. They ended up looking for leased properties that meet their specification in the procurement instruction in good condition and safety. Fifthly, innovative technology could improve communication between the clients and help save time on conducting meetings in one common place. , Thesis (MBA) -- Faculty of Business and Economic Sciences, Business School, 2023
- Full Text:
- Date Issued: 2023-12