11613 research outputs found
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Role of polyunsaturated fatty acids during infection of Caenorhabditis elegans
No full textThesis (Ph.D.(Microbiology))--University of the Free State, 2023During polymicrobial infection, interactions between different microbial species can alter host responses and/or microbial virulence and pathogenesis, often complicating patient treatment and resolution of infection. Polyunsaturated fatty acids (PUFAs) are not only crucial for normal function in mammalian systems, but are also proposed to act as endogenous antimicrobial molecules. Thus, we adopted Caenorhabditis elegans to mimic the Pseudomonas aeruginosa and Candida albicans polymicrobial infections found in humans. We determined the influence of arachidonic acid (AA) and eicosopentaenoic acid (EPA) supplementation on mono- and polymicrobial infection, fatty acid (FA) composition and egg retention of the nematodes, as well as on expression of FA metabolic genes. Supplementation with either AA or EPA in mono- and polymicrobial infections resulted in changes in FA profiles and PUFA biosynthesis pathway. We discovered that the degree of egg retention elicited by C. albicans and P. aeruginosa varied, with C. elegans exposed to both C. albicans and P. aeruginosa showing the highest level of egg retention compared to nematodes infected by either C. albicans or P. aeruginosa alone. Interestingly, the AA supplemented infected nematodes showed an increased level of egg retention, while EPA supplemented infected nematodes showed a significant decrease. Using the C. elegans model, we determined the effects of AA and EPA supplementation on the survival of nematodes with mono- and polymicrobial infection. We showed that the survival of the infected nematodes was influenced by PUFA-supplementation. EPA supplementation effectively reduced C. albicans virulence and inhibited hyphal formation, thus leading to a partial rescue of pathogen susceptibility.
However, this was not the case for P. aeruginosa infections. In fact, EPA supplemented nematodes infected with P. aeruginosa were more susceptible. Notably hyphal formation is an important component of Candida pathogenesis in mammals. Furthermore, polymicrobial infection resulted in synergistic virulence. However, C. albicans did not produce any hyphae in the co-infection of either AA, EPA supplemented or unsupplemented nematodes, this suggests that the increase in pathogenesis may be associated with increased P. aeruginosa pathogenesis. To further test the role of EPA in hyphal formation of C. albicans, we hypothesised that cytochrome P450 (CYP450) metabolises EPA to 17,18-epoxyeicosatetraenoic acid (17,18-EpETE), inhibiting C. albicans hyphal formation. We showed that 17,18-EpETE inhibits C. albicans hyphal formation in vitro and in vivo in C. elegans and that inhibitors of mammalian EPA-metabolising CYP450 enzymes, 17-octadecynoic acid (17-ODYA) and 6-(2-propargyloxyphenyl) hexanoic acid (PPOH) restored C. albicans hyphal formation in vivo. Lastly, the role of EPA on the physiology of C. elegans as well as C. albicans in vivo was investigated using gene expression analyses. Among the up-regulated genes, we observed several genes with potential roles in lipid metabolism, hyphal formation, detoxification, stress response and immune response. For instance, we observed an up-regulation of several involved in the synthesis of FAs, including fat-3, fat-4, fat-6, cyp-29A2 and cyp-37A1. Other up-regulated genes were those involved in immune response, such as cyp-37B1, daf-16, fipr-22, ilys-2, lys-5, lys-6, spp-12 and fat-3. Interestingly common genes involved in hyphal formation, such as CAS5, CRZ1, CTA4, ERG11, FCR1, SNQ2, TAC1, TEC1, YOR1 and ZCF3 were also up-regulated. Overall, the benefits of EPA supplementation may be two-fold, by inhibiting virulence factors of C. albicans and stimulating the immune response of the host. Thus, PUFA supplementation might be useful in the treatment of infections in patients caused by C. albicans and P. aeruginosa
The effect of core self-evaluation and career adaptability on the subjective career success of higher education employees
No full textDissertation (M.Com.(Industrial Psychology))--University of the Free State, 2023The South African labour market has witnessed significant transformations in the post-apartheid era as the nation prepared to integrate into the global economy. Despite improvements in the years between 2000 and 2017, persistent disparities in unemployment rates, skills shortages, gender imbalances, and stagnant wages have remained a challenge. The outbreak of the COVID-19 pandemic exacerbated these inequalities, disrupting economies, societies and workplaces globally and accelerating pre-existing workplace trends such as the gig economy, digitalisation, and automation. In this context, organisations, particularly in higher education, face the imperative to nurture digital skills, resilience and adaptability among employees to navigate the evolving career landscape. Central to this study is the concept of career adaptability, encompassing attitudes, behaviours and competencies used to navigate work roles, within the framework of Career Construction Theory (CCT).
This research delves into the adaptation process of employees in a higher education institution, exploring how they can enhance their career experiences in dynamic work environments. Subjective career success, reflecting an individual's personal evaluation of his or her career achievements and fulfilment, is investigated as a key outcome affected by core self-evaluation (CSE) and career adaptability (CA).
The study hypothesises that higher levels of CSE (representing adaptive readiness) and CA (representing adaptability resources) would positively influence the perceived subjective career success of higher education employees. A quantitative and explanatory research design was employed to test these hypotheses. Ethical considerations were addressed, and established scales were used for data collection via an electronic survey, resulting in a sample of 242 participants.
The holistic model, supported by statistical fit indices, reveals that higher CSE positively influences SCS, with evidence supporting the connection between CSE and SCS in various dimensions. CSE demonstrates a positive relationship with the eight SCS sub-dimensions, including authenticity, growth and development, influence, meaningful work, personal life, quality work, recognition, and satisfaction. These findings emphasise the role of CSE in shaping career trajectories, decision-making, and overall life satisfaction. Contrarily, while CA shows a significant relationship with the growth and development sub-dimension of SCS, its influence on other dimensions is not statistically significant, emphasising the importance of individual dispositions, particularly CSE, as stronger predictors of SCS. The analysis of age-related differences in SCS reveals no statistically significant variations, challenging prior findings and suggesting that factors beyond age significantly contribute to individuals' perceptions of career success.
This study contributes to the understanding of the complex interplay between core self-evaluation, career adaptability, and subjective career success in a rapidly changing work environment. The findings underscore the importance of self-belief and adaptability in shaping career outcomes, and offer valuable insights for individuals seeking to enhance their career prospects, as well as organisations aiming to cultivate a satisfied and successful workforce. Future research should further explore potential mediators and moderators of the relationship between career adaptability and subjective career success, providing a more comprehensive understanding of these dynamic constructs
Experiences of health sciences students residing on campus during university recess: a photovoice study
No full textDissertation (M.Sc.(Nursing))--University of the Free State, 2023This study addressed the lack of empirical research on the experiences of South African health sciences students residing on campus during university recess. The health professional governing bodies in South Africa require students to gain clinical competence through work-integrated learning, which is often undertaken during university recess. Yet, literature on this specific topic could not be retrieved. Studies on clinical learning in the health sciences environment focus solely on the clinical workplace, without considering students residing in campus residences during recess. The unknown struggles and potential challenges faced by health sciences students during recess could raise significant issues that higher education institutions in South Africa should consider. To address this research gap, participatory research utilising the photovoice method was employed to answer the research question: what are the experiences of health sciences students residing on campus during recess at a specific university? Four health sciences students were recruited through purposive sampling to participate in a series of workshops. They were provided with cameras to document their experiences on campus during university recess. Discussions and an exhibition of the photographs were conducted, resulting in the identification of 13 themes that were clustered into four, namely, sharing personal space, support services and structures, security, and character building and personal development. These clustered themes flagged that the co-researchers experienced a loss of sense of belonging, linked to inadequate support during university recess. Moreover, the study demonstrates the feasibility of implementing participatory research under challenging conditions, such as COVID-19 restrictions. The participatory method empowered co-researchers to advocate for themselves and others, thereby shedding light on issues that matter for institutional transformation. It would be advantageous to expand the research with more participants, across disciplines, and over longer periods of recess to inform policies and guidelines relating to recess periods
Criminal capacity of and criminal justice for offenders with bipolar disorder
No full textThesis(LL.D.(Criminal and Medical Law))--University of the Free State, 2023According to the World Health Organisation, bipolar disorder is the sixth most prevalent disability in the world.¹ Despite this, bipolar disorder remains largely unchartered within the South African juridical landscape. Therefore, the thesis investigates whether sufficient provision is made, both in the context of criminal justice and criminal capacity, for offenders who suffer from bipolar disorder within the South African criminal justice system. In doing so, the criminal justice systems of South Africa, the Netherlands, and the United States of America (USA) are examined, with specific reference to the tests for criminal capacity, relevant legislation, case law, and what constitutes both expert evidence and expert witnesses, respectively.
Sentencing options and alternative sentencing options, as they relate to mentally ill offenders, are also examined. Particular consideration is given to terbeschikkingstelling in the Netherlands and mental health courts in the United States. In addition, the advantages and disadvantages of both systems are thoroughly analysed. A proposal for a uniquely South African mental health court model is subsequently put forward, in the hope that this will pave the way in ultimately providing an improved alternative to conventional sentencing for offenders suffering from bipolar disorder.
___________________________________________________________________Volgens die Wêreldgesondheidsorganisasie is bipolêre versteuring die sesde mees algemene gestremdheid in die wêreld.¹ Ten spyte hiervan bly bipolêre versteuring grootliks onbekend binne die Suid-Afrikaanse juridiese landskap. Die tesis ondersoek daarom of voldoende voorsiening binne die Suid-Afrikaanse strafregstelsel gemaak word, beide in die konteks van strafregpleging en kriminele kapasiteit, vir oortreders wat aan bipolêre versteuring ly. Sodoende word die strafregstelsels van Suid-Afrika, Nederland en die Verenigde State van Amerika (VSA) ondersoek, met spesifieke verwysing na die toetse vir kriminele kapasiteit, relevante wetgewing, regspraak, en wat onderskeidelik deskundige getuienis sowel as deskundige getuies uitmaak.
Vonnisopsies en alternatiewe vonnisopsies word ook ondersoek, omdat dit verband hou met geestesongestelde oortreders. Besondere oorweging word gegee aan terbeschikkingstelling in Nederland en geestesgesondheidshowe in die VSA. Daarbenewens word die voor- en nadele van beide stelsels deeglik ontleed. ’n Voorstel vir ’n unieke Suid-Afrikaanse model vir geestesgesondheidshowe word vervolgens voorgelê, met die hoop dat dit die weg sal baan om uiteindelik ’n verbeterde alternatief vir konvensionele vonnisopleggings te bied vir oortreders wat aan bipolêre versteuring ly.
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Enhancing household welfare through perennial crop production in Northern Ghana
No full textAs Ghana seeks to diversify its agricultural export commodity trade away from its over-reliance on cocoa, empirical evidence is critical to inform policy direction on the implementation of programs to promote such an agenda. The objective of the study was to determine whether farmers who cultivate perennial crops as their primary source of livelihood have better welfare gains than farmers who cultivate perennial crops. The study used cross-sectional data collected from 386 farming households in the northern region of Ghana. The propensity score-matching technique augmented with a control function estimator was employed in order to account for self-selection biases in household characteristics that could invalidate the quality and magnitude of the estimates. Factors identified to positively and significantly influence households’ decision to cultivate perennial crops include number of male adults in a household, farm size, membership of farmer groups, value of agricultural credit, and distance from homestead to the farm. The empirical evidence further indicated that farmers who grow perennial crops have higher welfare gains in terms of consumption expenditure per capita, household income per capita, and farm income per hectare than farmers who grow annual crops as their primary source of income. On the other hand, annual crop farmers have a wider spread of income (income diversification) than perennial crop farmers. Sensitizing farming households to engage in perennial crop production, at the very least, as an alternative source of livelihood, will aid in the fight against poverty and food insecurity, as well as improve Ghana’s macroeconomic balances through agricultural export revenue.Publisher's versio
Effects of the density of invasive Lantana camera plants on the biodiversity of large and small mammals in the Groenkloof Nature Reserve (GNR) in South Africa
No full textMulti-scale approaches have been used to determine scales at which mammal species are responding to habitat destruction due to invasion, but the impacts of weeds on mammals have not been extensively studied, especially in Africa. Inside the Groenkloof Nature Reserve (GNR), we assessed how mammals are affected by an invasive weed Lantana camara. A series of models were applied to determine the differences in species abundance as well as richness, separated for large and small mammals. When diversity indices were used, an Analysis of Variance (ANOVA) revealed no statistically significant difference between treatments (F5 = 0.233, p = 0.945) for large mammals. The results of a Generalised Linear Mixed Model (GLMM) showed that vegetation type (Wald χ22 = 120.156; p < 0.01) and foraging guilds (Wald χ23 = 76.771; p < 0.01) were significant predictors of large mammal species richness. However, for small mammals, the results of a GLMM showed that only treatment type (Wald χ25 = 10.62; p = 0.050) was a significant predictor of the number of small mammals trapped. In addition, the ANOVA revealed statistically significant differences in species diversity between treatments (F5 = 0.934; p < 0.001) and by season (F1 = 9.122 p = 0.003) for small mammals. The presence of L. camara coupled with other predictors was associated with differences in large mammal abundances and diversity, and differences in how these large mammals were distributed across the landscape. Furthermore, the highest species diversity was found in the spring for small mammals. Therefore, for all the mammals studied, the presence of L. camara negatively affected species abundance, richness, and diversity, as well as how these species were distributed across the invaded and cleared areas.Publisher's versio
In vivo efficacy of curcumin and curcumin nanoparticle in trypanosoma congolense, broden 1904 (kinetoplastea: trypanosomatidae)-infected mice
No full textCurcumin (CUR) is known for its wide folkloric effects on various infections; however, its solubility status has remained a hindrance to its bioavailability in the host. This study evaluated the comparative effects of CUR and CUR-nanoparticle in vitro on T. congolense, T. b. brucei, and T. evansi. Additionally, CUR and CUR-nanoparticle anti-Trypanosoma efficacy were assessed in vivo against T. congolense. All the CUR-nanoparticles were two folds more effective on the T. congolense as compared to CUR in vitro, with recorded efficacy of 3.67 ± 0.31; 7.61 ± 1.22; and 6.40 ± 3.07 μM, while the CUR-nanoparticles efficacy was 1.56 ± 0.50; 28.16 ± 9.43 and 13.12 ± 0.13 μM on T. congolense, T. b. brucei, and T. evansi, respectively. Both CUR and CUR-nanoparticles displayed moderate efficacy orally. The efficacy of CUR and CUR-nanoparticles in vivo was influenced by solubility, presence of food, and treatment period. CUR-treated mice were not cured of the infection; however, the survival rate of the orally treated mice was significantly prolonged as compared with intraperitoneal-treated mice. CUR-nanoparticles resulted in significant suppression of parasitemia even though relapsed was observed. In conclusion, CUR and CUR-nanoparticles possess moderate efficacy orally on the trypanosomes as compared to the intraperitoneal treatment.Publisher's versio
Learning needs of caregivers of older persons in residential care facilities in rural South Africa: Unveiling unrealistic expectations
No full textIntroduction: The complexity of the caring needs of older persons in residential care facilities pose challenges for
which South African caregivers were found to be underprepared. Their inadequate education and training led to
varied quality of care, caregiver stress and burnout. The need was consequently identified to explore and describe
the learning needs of caregivers working in residential care facilities in a resource limited setting.
Methods: An explorative case study was undertaken and the multiple perspectives of stakeholders within the
geographical context were elicited by use of four nominal groups and a small group interview.
Results: Following a content analysis, the topics of basic nursing skills, hygiene, Alzheimer’s disease, medication,
communication, rights, and responsibilities, as well as staff monitoring, and evaluation were identified.
Conclusion: Most of the learning needs were beyond the expected caregiver tasks stipulated by the South African
Qualifications Authority. The authors question the unrealistic expectations set before these caregivers.Publisher's versio
Metagenomic assessment of nitrate-contaminated mine wastewaters and optimization of complete denitrification by indigenous enriched bacteria
No full textNitrate contamination in water remains to be on the rise globally due to continuous anthropogenic activities, such as mining and farming, which utilize high amounts of ammonium nitrate explosives and chemical-NPK-fertilizers, respectively. This study presents insights into the development of a bioremediation strategy to remove nitrates (NO3−) using consortia enriched from wastewater collected from a diamond mine in Lesotho and a platinum mine in South Africa. A biogeochemical analysis was conducted on the water samples which aided in comparing and elucidating their unique physicochemical parameters. The chemical analysis uncovered that both wastewater samples contained over 120 mg/L of NO3− and over 250 mg/L of sulfates (SO42-), which were both beyond the acceptable limit of the environmental surface water standards of South Africa. The samples were atypical of mine wastewaters as they had low concentrations of dissolved heavy metals and a pH of over 5. A metagenomic analysis applied to study microbial diversities revealed that both samples were dominated by the phyla Proteobacteria and Bacteroidetes, which accounted for over 40% and 15%, respectively. Three consortia were enriched to target denitrifying bacteria using selective media and then subjected to complete denitrification experiments. Denitrification dynamics and denitrifying capacities of the consortia were determined by monitoring dissolved and gaseous nitrogen species over time. Denitrification optimization was carried out by changing environmental conditions, including supplementing the cultures with metal enzyme co-factors (iron and copper) that were observed to promote different stages of denitrification. Copper supplemented at 50 mg/L was observed to be promoting complete denitrification of over 500 mg/L of NO3−, evidenced by the emission of nitrogen gas (N2) that was more than nitrous oxide gas (N2O) emitted as the terminal by-product. Modification and manipulation of growth conditions based on the microbial diversity enriched proved that it is possible to optimize a bioremediation system that can reduce high concentrations of NO3−, while emitting an environmentally-friendly N2 instead of N2O, that is, a greenhouse gas. Data collected and discussed in this research study can be used to model an upscale NO3− bioremediation system aimed to remove nitrogenous and other contaminants without secondary contamination.Publisher's versio
A peregrination: through spice
No full textDissertation (M.Arch. (Architecture))--University of the Free State, 2023In recent years, the field of architecture has witnessed a growing recognition of the significance of embodied sensory experiences in shaping our perception of space. How we interact with our surroundings extends beyond visual perception, encompassing the multisensory engagement with and movement through the environment. This corporeal journey employs the changing qualities of haptic experiences- smell, taste, sound, and bodily orientations. An emerging understanding of architecture as a sensorial medium opens exciting possibilities for exploring how cultural elements, such as food and its associated sensory experiences, can be translated into an embodied architectural journey. South Africa’s rich cultural diversity has fostered the emergence of vibrant communities, each bringing its unique heritage and traditions. Among these communities, Indian South Africans have enriched the country’s cultural fabric through their culinary practices and the use of aromatic spices, tantalizing the senses. The distinct flavours and fragrances found in Indian cuisine are deeply intertwined with personal, familial, and communal histories, forming an integral part of the South African identity. The culture of Indian spice is by no means static. To architecturally articulate this dynamic culture, the dissertation seeks to analogously map the smell-taste journey through different spices as a cinematographic journey through different architectural nodes and experiences. Taking this cinematographic journey will result in not only a visual but an embodied peregrination through the narratives interwoven within the history and culture of spice