4667 research outputs found
Sort by
The effect of didox on the induction of cell death in lung cancer cells challenged with SARS-CoV 2 recombinant spike proteins
Full text linkThesis (M.Sc. (Biochemistry)) -- University of Limpopo, 2024Lung cancer still accounts for most deaths caused by cancer in South Africa. Patients with lung cancer are more susceptible to coronavirus disease 2019 (COVID-19) fatal consequences due to their reduced lung function and immunosuppression. The COVID-19 causative agent, severe acute respiratory syndrome coronavirus 2 (SARS-CoV 2), is highly transmissible, and upon infection it triggers an inflammatory cytokine storm, consequently causing organ or tissue damage. Various therapeutics have been researched for the development of effective anti-cancer and anti-inflammatory treatment to counteract effects caused by COVID-19 on cancer patients. Didox, a ribonucleotide reductase inhibitor, is a potential therapeutic agent with anti-cancer, anti-viral and anti-inflammatory properties. Therefore, the study was aimed at determining the effects that Didox has on lung cancer cells that were exposed to SARS-CoV 2 recombinant spike proteins. To achieve this aim, the antioxidant activity of Didox was determined using DPPH and FRAP assays, while viability, morphology, nuclear integrity, induction of apoptosis and oxidative stress in A549 lung cancer cells were determined using the MTT assay, light microscopy, nitric oxide assay, annexin V and PI assay, and oxidative stress assay, respectively. Both the DPPH and FRAP assay revealed the free radical scavenging properties and ferric reducing power properties of Didox, observed in a concentration-dependent manner, respectively. Didox reduced the nitric oxide production induced by SARS-CoV 2 spike proteins and the same effect was observed on ROS induced by SARS-CoV 2 in A549 lung cancer cells. A decreased population of A549 cells and cell shrinkage was observed with an increase in concentration of Didox in a time-dependent manner. The cytotoxicity assay showed that the viability of the A549 decreased with an increase in concentration of Didox. The population of apoptotic cells increased with exposure of A549 cells to SARS-CoV 2 and Didox, showing that Didox accelerated SARS-CoV 2 induced an inflammation-mediated cell death. In conclusion, Didox exerted a cytostatic effect on A549 cells and also reduced the oxidative stress induced by SARS-CoV 2 recombinant spike proteins in A549 cells. Thus, these antioxidant properties render Didox a potential therapeutic candidate for further research in the development of cancer and COVID-19 treatment options
An investigation of fermentation and maturation temperatures on the chemical and sensory characteristics of the starter-culture based marula fruit wines
Full text linkThesis (M.Sc. (Microbiology)) -- University of Limpopo, 2024Temperature is an important factor that affects the growth and activities of wine microorganisms, which then influences the chemical profile and consequently the organoleptic characteristics of the wine. The aim of the study was to evaluate the influence of varying temperatures for fermentation, maturation and storage conditions on the chemical, nutritional and sensory characteristics of starter-culture-based marula fruit wines. Clarified sweetened marula fruit juices were fermented at 15 °C and 25 °C, and one portion from each was matured and aged at the same temperatures. Another portion from each fermented wine was matured and aged at 4 °C, whereas the reference wine was fermented at 25 °C using the clarified unsweetened marula fruit juice, and matured and stored at 15 °C and 4 °C. The microorganisms isolated from bottled aging wines were identified with the 16S rRNA region. Organic chemicals such as sugars, alcohols, glycerol, pH, acids, esters, tannins, and antioxidants were determined using conventional chemical analysis method, spectroscopy and chromatographic methods. Selected nutrients such as minerals, proteins, cholesterol, crude fats and vitamin C were determined as well. All the wines were subjected to panel testing. The microbial species that were identified in the aging marula wines at different temperatures include Saccharomyces cerevisiae, Lactobacillus brevis, Acetobacter lovaniensis, Acetobacter ghanensis, Raoultella terrigena, Raoutella ornithinolytica and Bacillus species. The naturally occurring citric acid which influences titratable and total acidity in wines was detected at higher concentration, while lactic and acetic acids were the least produced. An increase in higher alcohols and spicy esters was observed in the wines that were produced at 25 °C, whereas the level of fruity esters increased in wines that were stored at 4 °C. The wines preserved and improved some of the essential nutrients such as proteins and minerals, whereas vitamin C levels dropped in the wines that were produced at elevated temperatures. The wine that was fermented at 15 °C, matured and stored at 4 °C was the most appreciated as compared to wines that were produced at elevated temperatures. These findings asserted the development of good flavours in wines produced at lower temperatures, as is the case with marula fruit wine wherein the complex intensive flavour profile and good balance can be attained at lower production temperatures.University of Limpop
Effectiveness of the employee wellness programme in supporting employees' psychosocial well-being during covid-19 pandemic and beyond in the Limpopo Department of Agriculture and Rural Development
Full text linkThesis (M. Dev. (Planning and Development)) -- University of Limpopo, 2024The study aimed to explore and describe employees' perceptions of whether the Employee Wellness Programme within the LDARD effectively supported their psychosocial well-being during the COVID-19 pandemic and beyond. The study adopted a mixed-methods research methodology where data were collected using both quantitative and qualitative data collection tools. A quantitative survey questionnaire was administered to 58 employees, while semi-structured interviews were conducted with 4 Assistant Directors who are supervisors. The study applied a census method of sampling, whereby the agricultural advisors within LDARD Capricorn district were part of the study. The study's findings indicated that employees at LDARD perceived the Employee Wellness Programme (EWP) as ineffective in supporting their psychosocial well-being when dealing with personal and work-related challenges during the COVID-19 era and beyond. This implies that some employees did not fully understand the significance of utilising the EWP to improve their well-being and overall job performance to enhance effective service delivery. The psychological dimension of the EWP wherein therapeutic counselling is offered is not being utilised optimally due to significant concerns over the guarantee of confidentiality over their problems. Although fewer employees shared a positive outlook on the EWP, more employees may benefit from attending awareness sessions regarding the program to encourage their health-seeking behaviour and take advantage of peer support from colleagues. Furthermore, outsourcing the psychosocial therapeutic counselling services of the EWP may provide an alternative for some employees and assure their total privacy off-site the workplace. In conclusion, this study has added to the body of knowledge for entities that provides internal EWP as well as for future research, particularly in the provincial department
Evolution of acoustic communication and habitat type influence in the avian species, sabota lark calendulauda sabota (alaudidae)
Full text linkThesis (M. Sc. (Zoology)) -- University of Limpopo, 2024Habitat acoustics has been proposed to be involved in producing selective forces that mould bird vocalisations into the sounds we hear when birds vocalise. The influence of habitat on bird vocalisations is well-documented, mostly in bird species in the Americas rather than in Africa. The Sabota Lark Calendulauda sabota is near-endemic to southern Africa and has a widespread distribution in habitats ranging from well-developed Savanna woodland to Karoo and semi-desert scrub. However, to my knowledge, no records of published studies have endeavoured to quantitatively describe the vocal structure of the Sabota Lark or the effects of habitat on its vocalisations. This makes the Sabota Lark an ideal candidate to investigate the effect of habitat type and structure on bird vocal structure. This study investigated the effect of habitat on the vocalisations of the Sabota Lark and whether the Acoustic Adaptation Hypothesis applies to the Sabota Lark. Fieldwork was conducted during breeding seasons in the sites that represented semi-arid (Vachellia) and moist Savanna (broad-leaved woodland) and the dry Nama Karoo shrublands. Songs were analysed using a bioacoustics sound analyses software. A total of 992 song strophes were extracted, and spectrograms were generated from which descriptions of songs were done. Seven spectrogram parameters of 878 song strophes were analysed using univariate one-way ANOVA and t-test. Multivariate (Principal Component Analyses – PCA and Linear Discriminant Analyses – LDA) statistical analyses were performed in two parts to respectively include: 1) analyses of a comprehensive dataset with all the remaining seven vegetation types included and 2) analyses of a reduced dataset comprising only the two vegetation types with the highest sampling (viz., Bushmanland Basin Shrubland – BBS and Musina Mopane Bushveld – MMB).
The Sabota Lark emerged as a species with large and complex song variations between individual birds and within and between different habitat types. The individuals gave many unique song types and song strophes. Furthermore, this species explored both types of song presentation or singing styles as some individuals repeated song types at least twice before switching to another song type. This singing style is called “eventual variety”. The
other birds rendered their song types once and never twice in succession. This is called “immediate” variety, meaning they switched to new song types immediately without repeating songs that have already been sung. This was observed both within individuals and among individuals in different habitat types. The means of the parameters of song strophes of the Sabota Larks among the vegetation types were highly significantly different, indicating that variances in songs between vegetation types were not equal. However, most parameters were significantly different contrary to the study predictions; Therefore, future studies should include a large sample size with equal representation across habitats, and the vegetation structure should be quantified
Processing of mining waste containing phosphogypsm and sodium sulphate for recovery of calcium carbonate ,sodium carbonate and rare earth metals
Full text linkThesis (Ph.D. (Chemistry)) -- University of Limpopo, 2024Waste gypsum from the fertilizer industry, sodium sulphate and magnesium sulphate rich brines from the mining industry and power stations can be utilized for the recovery of valuable products, as an alternative to stockpiling as waste dumps, or stored in brine ponds respectively. Waste gypsum can be used for the recovery of nano calcium carbonate, sulphur, and rare earth elements (REEs) (cerium, praseodymium, lanthanum, neodymium, and samarium). Sodium sulphate can be processed into sodium carbonate, sulphur, and sodium bisulphide. Magnesium sulphate can be processed to magnesium hydroxide, and in combination with sodium sulphide, sodium bisulphide and sodium sulphate can be produced. The proposed project allowed the generation of profits from waste as sodium carbonate has a value of R7 000/t, nano calcium carbonate a value of R14 000/t, magnesium hydroxide a value of R7 000/t and the global REEs market of R139.4 billion in 2023. Rare earth elements are used for magnets and due to its use in the electronic industry, and due to limited resources, it is of strategic value to the Western Word. Rare earth elements in phosphogypsum amounted to 4.48 mg/g gypsum and were collected with the crude CaCO3. Rare earth elements were present in lower concentrations in AMD, ranging from were 0.7 to 9.1 mg/L.
The Mintek Pyrosim software model was used to predict the products formed under the conditions that were studied experimentally. A muffle furnace was used to thermally reduce CaSO4 to CaS and BaSO4 to BaS. OLI and beaker studies were used to determine which compound will precipitate out and which compounds/elements will stay in solution. The pyrosim studies and the muffle furnace studies both showed that CaSO4 and BaSO4 can be converted to CaS and BaS, respectively, through reduction with coal at 1000 °C. Less energy was needed for the conversion of BaSO4 into BaS (1 480 MJ/t coal) than for the conversion of CaSO4·2H2O into CaS (3 657 MJ/t coal). Furthermore, it was showed that CaS can be used to produce Na2CO3, CaCO3 and nano CaCO3.
Acid mine drainage (AMD), a notorious kind of pollution associated with both active and abandoned mining sites, needs to be treated with the aim of achieving net zero waste. The ROC (Reverse Osmosis/Cooling) process can be used for the treatment of AMD though neutralization with Na2CO3 for the removal of metals, desalination with
reverse osmosis (RO), freeze-crystallization for recovering Na2SO4 from the RO brine, and processing of Na2SO4 via Na2S to its raw material, Na2CO3. The conditions needed for the processing of Na2S to Na2CO3 were investigated. It was found that: (i) Na2S can be reacted with CO2 to form NaHCO3(aq) and NaHS(aq), (ii) the latter two compounds can be separated though freeze-crystallization as NaHCO3 has a lower solubility at 0°C, and (iii) NaHCO3 can be converted into Na2CO3 though heattreatment. OLI simulations also confirmed that NaHCO3 and NaHS were formed when Na2S was reacted with CO2.
It was showed that Mg(OH)2 can be produced as a single solid compound when reacted with Na2S, as the other product, Na2SO4, has a high solubility. Mg(OH)2 will also form when reacted with CaS or BaS, but this approach will have the disadvantage that the solid, Mg(OH)2 is mixed with other solids, namely CaSO4·2H2O or BaSO4. The formation of Mg(OH)2 was also predicted by OLI simulations. Magnesium oxide can be formed from Mg(OH)2 through heating. These developments will contribute to achieve zero waste generation during solid waste treatment. Hydrogen sulphide can be converted to S by using the Claus process. In this study, H2S gas was produced when CaS or Na2S was contacted with CO2. This H2S was converted to S by contacting it with Fe3+ through OLI software. The effect of Fe3+ concentration was shown by stepwise by increment of the Fe2(SO4)3 dosage from 0 to 3000 mmol/L. It was noted that FeS2 formed when Fe2(SO4)3/H2S mole ratio was 0.5 with further dosing of Fe2(SO4)3, the formed FeS2 was converted to mainly S8. H2S was also oxidized with O2. OLI software showed that 50 mmol O2 was needed for oxidation of H2S to S8.
The study also focused on the formation of CaSO4·½H2O from CaSO4·2H2O. It was noted that CaSO4·½H2O formed at temperatures of 240 °C and 180 °C when 60 min and 120 min reaction time was allowed, respectively. In the same section, gypsum and the reductant were determined if they should be processed as a powder or as a solid in the form of a brick or a tile. It was noted that hard gypsum formed when anhydrite was contacted with water in the presence of activated carbon.Technology & Human Resources for lndustry Programme (THRIP)
ROC Water Technologies
TIA Seed Fund
French South African Agricultural Institute (F’SAGRI)
National Intellectual Property Management Office (NIPMO
Influence of drying methods on the nutritional composition of moringa (Moringa oleifera) leaves
Full text linkThesis (M. Sc. (Agronomy)) -- University of Limpopo, 2024Moringa (Moringa oleifera) is a multipurpose tree that has amazing nutritional, healing, and preventative potentials. It has been identified as one of the most assuring species in ameliorating/improving micronutrient malnutrition. However, the fresh Moringa leaves tend to lose quality over time due to short shelf-life, approximately 2 to 3 days. Therefore, in this study, different drying methods were investigated to assess the preservation of nutrients. Moringa leaves were harvested during the summer season from December 2022 to March 2023 and taken to the University of Limpopo Plant Production laboratory, where the treatments were laid out in a Complete Randomized Design (CRD). Moringa leaves were subjected to sun drying (1), shade drying (2), oven drying at 30 °C (3), and oven drying at 60 °C (4) to determine the influence of drying methods in terms of maximum preservation of nutrients. Each treatment had 5 replications of trays for precision and validation of the results. The nutrients of the leaves were determined using standard analytical methods. Data were analysed and interpreted using one-way ANOVA using GenStat (2018). The differences between the treatment means were compared for significance at a 5 % probability level using the Least Significant Difference (LSD) test. The findings from this study revealed a significant difference (p<0.05) among the drying methods in moisture, fat, ash, magnesium (Mg), phosphorous (P), potassium (K), and calcium (Ca). Iron (Fe) at 94.5 mg, ash at 12.17 %, potassium (K) at 1.43 %, and phosphorous (P) at 0.32 % were found statistically superior from samples dried in the oven at 30°C. The study revealed the shortest drying period from the leaves dried in the sun and oven at 60 °C drying method, which took 24 hours for the complete moisture loss. There was no significant difference among the drying methods in the Protein, zinc (Zn), and Sodium (Na) content. The study showed a significant influence of drying methods on the composition of chemicals and nutrients in Moringa leaves. Therefore, oven drying method at 30 °C is recommended to enhance the quality of dried Moringa leaves to meet standards of food security in terms of nutrient retention.Food and Beverage Manufacturing Sector and
The Department of Plant Production, Soil Sciences, and Agricultural Engineerin
Application of survival analysis and machine learning models to age at first marriage among women in South Africa
Full text linkThesis (M. Sc. (Statistics)) -- University of Limpopo, 2024Understanding factors influencing the age at first marriage is crucial for addressing
social issues, promoting gender equality, and ensuring women’s wellbeing.
This research aims to identify key determinants of age at first marriage
for South African women. The discrete survival tree approach is applied to
analyze data and identify factors influencing women’s age at first marriage.
Key individual variables, such as birth year, ethnicity, education level, age at
first marriage, and province, are used in the analysis. The performance of
this model is compared with that of Random Forests and Classification and
Regression Trees using the C-index to determine the best-performing model.”
All three models provided valuable insights, but Random Forest emerged as
the most accurate age predictor at first marriage. Key determinants identified
were province of residence, birth year, and educational level. These findings
can contribute to policy-making aimed at improving the well-being of women
in South Africa through targeted interventions.NEPTT
Exploring the use of indigenous crops for heavy metal phytoremediation of mine contaminated soils
Full text linkThesis (M. Sc. (Soil Science)) -- University of Limpopo, 2024Soil contamination with heavy metals poses a significant environmental risk and is one of the world’s most pressing issue. People's health and soil are being seriously harmed by heavy metal pollution in mining locations. A crop-based technique called phytoremediation employs plants to either extract and remove pollutants from the soil or lessen their availability. The objectives of this study were to determine whether the selected indigenous crops would decrease heavy metal concentration in mine polluted soils through phytoremediation; and to determine whether the growth of selected indigenous crops will be affected by phytoremediation. A pot study comprising of 5 treatments which were arranged in a randomized complete block design (RCBD), replicated 4 times was conducted at the Green Biotechnology Research Centre (GBRC). The treatments consisted of: Amaranthus hybridus (A), Cleome gyanandra (C1), Bidens pilosa (B), Cucumis africanus (C2) and control (C0). Soil samples used in the study were collected from Tikhontele farm in Barberton, Mpumalanga. Soil samples were also analysed at the Soil Science Laboratory at the University of Limpopo and Limpopo Agro-Food Technology Station (LATS) for soil physicochemical properties (soil texture, soil pH (H2O and KCl),electrical conductivity (EC), organic carbon (OC), soil phosphorus (P) and basic cations (Ca, K, Mg and Na)). Four non-essential heavy metals, Arsenic (As), Cadmium (Cd), Chromium (Cr) and Lead (Pb) were also extracted. Crop species used were analysed for growth parameters, leaf length, stem diameter, chlorophyll content and the number of leaves were counted weekly. Bioaccumulation factor (BAF) data was computed using Genstat 18. The results revealed that all the crop species were able to decrease the heavy metals from the mine contaminated soils, the control of the study also showed a decrease in the heavy metals except for Cd. The results show that Pb was the highest reduced heavy metal in the soil. Treatment effects were highly significant for Pb, significant for As and not significant for Cr and Cd. The BAF of the different crops for the different heavy metals was below 1. Furthermore, results showed that BAF was generally high for Pb and low for Cr. The study found that the growth of crops was not affected by mine contaminated soils during phytoremediation. These results confirmed that these crops species were effective phytostablisers of As, Cd, Cr and Pb
Spelling errors by Grade 9 Sepedi Home Language learners in essay writing at Koloti Circuit, Capricorn North District, Limpopo Province, South Africa
Full text linkThesis (M. Ed. (Language Education)) -- University of Limpopo, 2024This study investigated the spelling challenges faced by Grade 9 Sepedi Home
Language (SEPHL) learners when writing essays. The objectives of the study were to
understand the cause of the spelling errors made among Grade 9 SEPHL learners
when writing essays and to propose strategies on how teachers and learners can
overcome the challenges associated with incorrect spelling. The study used the
qualitative research approach and observation, document analysis and semi structured interviews for data collection. The study employed purposive sampling to select eight SEPHL learners and two SEPHL teachers from a selected school. The study used the interpretivism paradigm to interpret the findings. The data was analysed through the thematic analysis technique. The findings show that parents do not check their children’s schoolwork and are not involved in their children’s studies. Based on the findings, the study recommended that learners familiarise themselves with SEPHL alphabets, practice writing regularly, using a spell-check tool, consult reliable resources and use a dictionary to improve their spelling. Furthermore, teachers and parents should help learners to improve their spelling and writin
Evaluating the food safety standards and competitiveness of South Africa's oranges in strategic Asian Markets
Full text linkThesis (Ph. D. (Agricultural Economics)) -- University of Limpopo, 2024This study aims to measure the effect of food safety standards and competitiveness of South African orange exports destined for strategic Asian markets. The study goal is to provide policymakers with insights to assist South Africa secure a larger market share in Asia by addressing critical factors. The research focuses on ten (10) strategic Asian markets: Hong Kong, India, Indonesia, China, Thailand, Japan, Malaysia, the Philippines, Vietnam, and South Korea. The study sets out to outline the composition and trends in South Africa’s orange exports to these Asian markets; analyze the competitive performance of other countries; identify key challenges and areas for improvement within the domestic orange industry and further assess the food safety requirements in these markets. The study employed both primary and secondary data. The first objective was based on desktop analysis and the data was sourced from reputable data platforms. The findings indicated that South Africa has seen significant growth in orange exports to Asian markets, surpassing Europe in 2005 and 2006. Despite a slight decline in 2007, Asia remains a critical market for South African exports. South Africa’s competitive performance against the competing countries in Asian markets was measured using the relative comparative advantage (RCA), net export index (NXi), relative trade advantage (RTA), and constant market share (CMS) analysis. South Africa’s orange industry demonstrated a strong comparative advantage, with RCA values consistently high with 25% indices indicating robust competitiveness. Despite competition from countries like Egypt and Greece, South Africa maintains a strong position. The net export index (NXi) reported an average near 100 indicating the favourable net export performance of the South African orange industry. The main constraints and drivers of the South African orange industry were measured using a distributed survey of the exporters of oranges. A total of 102 surveys were distributed to various stakeholders in the orange industry, with 67 completed responses, yielding a response rate of 65.7%. The main challenges that discourage the local orange competitiveness include issues like the quality of unskilled labor, political trust, electricity supply, health concerns, land reform policies, BEE policies, and crime. Additionally, poor infrastructure and ineffective trade agreements exacerbate these challenges. Specifically, the poor performance of South African ports leads to higher freight costs and delays, negatively impacting product quality and profitability. Lastly, the gravity model was utilized to assess the effect of food safety standards on South African orange exports through STATA. It was revealed that an increase in importers' GDP by 1% decreases South Africa's export performance, while a rise in South Africa's GDP enhances it. Population growth in these markets positively influences export volumes. Furthermore, the exchange rate volatility at the 5% level appears to support rather than hinder export growth, suggesting resilience within the industry. The study highlights that Technical Barriers to Trade (TBT) and Sanitary and Phytosanitary (SPS) measures significantly hinder South Africa’s orange exports. These barriers are statistically significant and align with existing literature, emphasizing the need for better negotiation and policy alignment.
Therefore, to enhance food safety compliance in South Africa’s orange industry, it is crucial to implement robust monitoring systems that adhere to technical barriers to trade and sanitary and phytosanitary standards. This will improve the quality of oranges and reduce shipment rejections, leading to better access to Asian markets. Developing specific trade agreements to address TBT and SPS barriers will improve market access and lower compliance costs, while ongoing analysis of market data will help the orange industry adapt to changing conditions and seize emerging opportunities. Additionally, investment in port infrastructure and modern transportation systems through public-private partnerships can lower freight costs and shipping delays, ultimately improving oranges quality and competitiveness in price-sensitive markets. Targeted training programs to improve labour quality and productivity will enhance agricultural practices and post-harvest handling, supporting South Africa’s competitiveness in Asian markets. Political and economic stability is essential for fostering a favourable business environment. Engaging with the government to address land reform, empowerment policies, and crime will build trust and attract investments in the orange industry. Financial strategies like hedging are needed to mitigate exchange rate risks and ensure stable revenues. Marketing efforts highlighting the quality and sustainability of South African oranges can enhance presence and customer loyalty. Collaboration between industry leaders and government through a dedicated task force will address infrastructural and policy challenges, leading to effective operational improvements. Continuous monitoring of economic indicators will facilitate the refinement of export strategies, ensuring resilience and competitiveness in Asian markets