South East Academic Libraries System (SEALS)
Not a member yet
69550 research outputs found
Sort by
Halogenated Aza-BODIPY dyes for photodynamic anticancer and antimicrobial activity studies
Get PDFThis thesis reports on the synthesis and characterisation of differently substituted aza-BODIPY dyes for use in photodynamic antimicrobial chemotherapy (PACT) and photodynamic therapy (PDT) activity studies. The aza-BODIPY dyes were synthesised by adding phenyl and naphthyl rings at the 3,5-positions of the aza-BODIPY core, with methylthiolphenyl (9a and 9b, respectively) or thien-2-yl rings (9c and 9d, respectively) at the 1,7-positions. 9a-c were iodinated at the 2-position to form 10a-c, respectively, while 9d was diiodinated at the 2,6-positions to form 10d. The methylthiolphenyl-substituted dyes (10a and 10b) were successfully conjugated to gold nanoparticles (AuNPs) to form nanoparticles conjugates (10a-AuNPs and 10b-AuNPs), while attempts to conjugate the thien-2-yl-substituted dyes were unsuccessful. The photophysicochemical properties of 9a-d, 10a-d and nanoconjugates 10a-AuNPs and 10b-AuNPs were investigated to determine their suitability for use in the applications. Adding heavy atoms such as iodine at the 2,6-positions of the aza-BODIPY led to enhanced singlet oxygen generation since these dyes displayed moderate to high singlet oxygen quantum yields. None of the dyes exhibited any fluorescence. The PACT activity studies for 9c-d, 10a-d, and the 10a-AuNPs and 10b-AuNPs were carried out against Staphylococcus aureus and Escherichia coli with a Thorlabs M660L3 light-emitting diode (LED) with an irradiance of 280 mW/cm2 for all dyes other than 10d. A Thorlabs M730L4 LED with an irradiance of 160 mW/cm2 was used for 10d. Time dependence studies were only carried out against Staphylococcus aureus, so very low log reductions were observed against Escherichia coli in initial concentration studies. The 10a-AuNP and 10b-AuNP nanoconjugates exhibited high antimicrobial activity with a log reduction of 9.41 and 0.00% viable colonies, while the iodinated aza-BODIPY had a log reduction of 8.94. The in vitro photodynamic therapy activities and dark cytotoxicity were investigated against human MCF-7 breast cancer cells for dyes 9c-d and 10c-d with a Thorlabs M660L3 LED (280 mW/cm2) for all dyes. The dark cytotoxicity was minimal in each case with IC50 > 50. Iodinated dyes 10c and 10d had IC50 values of 11.6 and 8.2 μM, respectively, and non-iodinated dyes 9c and 9d had IC50 values of 12.5 and 19.2 μM. The heavy atom effect associated with the iodine atoms increases the singlet oxygen quantum yield and enhances the suitability of the dyes for photodynamic therapy.Thesis (MSc) -- Faculty of Science, Chemistry, 202
Freshwater invasive alien crayfish species in South Africa: testing eDNA assessment and DNA barcoding
Get PDFThe expansion of the wild populations of the two invasive alien crayfish species, i.e., Cherax quadricarinatus and Procambarus clarkii in South Africa is of high concern. Given this, innovative and improved monitoring methods are required to be explored in order to effectively detect and manage their spread. Environmental DNA (eDNA) has shown promising and reliable results to detect and monitor alien crayfish in freshwater systems even at low densities. This research study aimed to field-test the application of eDNA for detecting and monitoring invasive alien freshwater crayfish species (IAFCs) in South African freshwater systems (Chapter 2). Further, this study also aimed to confirm the true taxonomic identity of the IAFCs in South African freshwater systems by using DNA barcoding to avoid potential misidentifications with morphological identification alone (Chapter 3). Also, ectocommensal temnocephalans and leeches attached to the crayfishes were also identified with DNA barcoding. The mitochondrial COI gene fragment of the crayfishes and the ectocommensal temnocephalans and leeches was amplified, sequenced, and used for species identification. For eDNA monitoring of C. cainii, C. quadricarinatus and P. clarkii, water samples were collected from Eastern Cape, Free State and KwaZulu Natal sites that are known to house these species. The current study did not detect the eDNA of the wild populations of both C. quadricarinatus and P. clarkii. This failure was encountered despite employing several methods, such as, end-point polymerase chain reaction (PCR), quantitative PCR (qPCR) and next-generation sequencing (NGS). The eDNA assessment to detect IAFCs in the wild populations is discussed in detail, and corrective measures suggested (Chapter 2). However, only C. cainii was able to be detected by eDNA. Cherax cainii is housed/farmed in an aquaculture facility (Vaughn Bursey’s Stock Farm in Eastern Cape) with large number of individuals per pond. For this, NGS was able to detect C. cainii but the other two methods, end-point PCR and qPCR were not able to detect the species. Based on the results, refinement of eDNA monitoring methods for the South African freshwater systems is recommended. Evaluation of different DNA collection methods, preservation, DNA extraction kits and primer design to obtain effective eDNA detection is discussed as possible sources of error. Interestingly, the newly established population of P. clarkii in Mimosa Dam in Free State was infested with alien leeches, that were confirmed by DNA barcoding to be Helobdella europaea and Helobdella octatestica. Consequently, this study reports for the first time in South Africa the presence of this alien freshwater leeches. The presence of alien leeches and P. clarkii suggests a double invasion in Mimosa Dam, P. clarkii seems to continue expanding its range in the country. However, the long-established population of P. clarkii in Driehoek Farm in Mpumalanga, which has been in the country for over 30 years did not have any leech or temnocephalan infestation. This could suggest several interesting ecological phenomena, including environmental filtering over time of the co-invaders, differential source populations, and post-introduction adaptation.Thesis (MSc) -- Faculty of Science, Zoology and Entomology, 202
The dissipation of marital assets pending a divorce order in South Africa: a proposal for reform
Get PDFDissipation of marital assets takes place where one spouses uses the marital assets with the intention to frustrate the equitable distribution at the dissolution of marriage. This kind of behaviour usually occurs when one spouse anticipates a divorce or when the final divorce order is pending. In this context then, this thesis aims to critically analyse the effectiveness of the legal remedies available to spouses who are negatively affected by the dissipation of marital assets in marriage in community of property and marriage out of community of property with accrual. In this thesis the question is asked: does the current law adequately protect one spouse from another spouse unfairly hiding or dissipating assets from their estate to prevent the equitable distribution of these assets to the other spouse on divorce? In order to answer this question, this thesis proceeds by examining each of the remedies in detail, looking specifically at the statutory remedies set out in the Matrimonial Property Act 88 of 1984, specifically those contained in ss 8, 15 and 20 of that Act. It also considers remedies found in the common law. Ultimately, the study finds that these remedies do not provide adequate protection to spouses affected by the dissipation of marital assets and looks at the particular reasons for this finding. The study then concludes by proposing reforms to provide better protection to affected spouses. These legal reforms include: amending the legislative framework, changing the determinative date of the accrual, legislating a requirement for full disclosure of assets in terms s 8(1) of the Matrimonial Property Act and, finally, advocating for a flexible interpretation of the requirements of s 20 of the Matrimonial Property Act and the common law anti-dissipation remedy.Thesis (LLM) -- Faculty of Law, Law, 202
Application of in vitro release testing (IVRT) to assess “sameness”/differences of topical clotrimazole formulations
No full textEmbargoed. Possible release date early 2025 pending publications.Thesis (MSC Pharm) -- Faculty of Pharmacy, 202
Workplace discrimination based on pregnancy
Get PDFIn the past, South Africa was marked by widespread discriminatory practices, many of which still exist to date. This study investigates the persistent discrimination against pregnant women. The study revealed that in South Africa, pregnant women continue to face discrimination in employment and are often denied the right to go on maternity leave, nursing or breastfeeding and childcare facilities. Presently, pregnancy is listed as a prohibited ground for discrimination in the South African Constitution as well as many ILO Conventions. Similarly, the South African labour law framework which gives effect to the Constitution provides for the protection of women and pregnant workers. This protection comes in the form of measures that proscribe dismissal and discrimination based on. Despite these legislation, this study finds that the less favorable treatment of women and pregnant workers in South African workplaces has become increasingly common, and this has turned into a contentious subject. This study focused on labour legislation that has been developed to safeguard pregnant women in the workplace in light of applicable constitutional protections. Notwithstanding these legislative protections for pregnant women in the workplace, the analysis shows that many pregnant women continue to be treated unfairly due to their pregnancies or for reasons linked to their pregnancies. Consequently, there has been a regression in the actual execution of laws and regulations protecting pregnant workers. The study highlights the need to establish mechanisms to ensure that legislation protecting pregnant workers in the workplace achieves its intended purpose and is implemented properly. Consequently, this study presents pertinent suggestions about the implementation of labour legislation so that the employment rights of women and pregnant workers are adequately safeguarded.Thesis (LLM) -- Faculty of Law, School of Mercantile Law, 202
The dismissal of an employee who refuses to vaccinate against Covid-19
Get PDFAbstract.Thesis (LLM) -- Faculty of Law, School of Public Law, 202
Action Research reflecting the process of a collaborative, multi-theoretical group intervention with foster parents of children affected by childhood trauma
Get PDFChildren are received into the Care of the State in the Republic of Ireland due to chronic or acute maltreatment in their families of origin. Maltreatment may include neglect; physical, sexual, or emotional abuse; exposure to domestic violence; or a combination of these. Resulting emotional and behavioural consequences may be challenging to foster parents who might experience stress, secondary trauma, compassion fatigue or burnout, which along with the child’s emotional and behavioural difficulties can result in placement breakdown. After reviewing the literature on fostering internationally and in Ireland, this study sought to determine the types and level of stress in a sample of foster parents and the types of challenging emotional and behavioural difficulties of their fostered children. Results revealed that foster parents found fostering stressful; factors included biological parents; organisational issues; and the child’s behaviour. According to the foster parents, nearly 60% of the foster children in this sample were showing high levels of emotional and behavioural distress. These difficulties differed according to age and gender. Adolescent Girls and Young Boys (5 – 11 years) were reported as having the most difficulties, including symptoms of behavioural and Conduct Disorder (CD). Symptoms associated with CD were reported in at least 40% of every age and gender category of children over five years. Further, this study outlines the development, facilitation and outcomes of a small group psychoeducational-reflective foster parenting Course, involving six separate groups of parents (n=38) each meeting for eight sessions. In this Course, foster children were conceptualised from a bio-psycho-social-ecological viewpoint, utilising theoretical concepts from Prenatal Development, Attachment and Trauma, pertaining to vulnerable children to illustrate the cumulative effects of adversities. Time for discussion and reflection on the material was structured into the Course. This combination of knowledge, practical skills, reflection and support for parents aimed to promote healing relationship-based practices for the child within their foster home. This multi-faceted study was grounded in Community Psychology, using mixed methods to gather data during action research processes, to reflect the different components of an action cycle. Ideas and modifications to the Course based on feedback from the foster parent participants’ experiences have been included. It is recommended that the Course be provided to other foster parents and audiences such as social workers, teachers and solicitors. Furthermore, suggestions are made regarding assessment, diagnosis and interventions for foster children and parents, based on a multidisciplinary consultancy model.Thesis (PhD) -- Faculty of Humanities, Psychology, 202
The determinants of manufacturing sector growth among East African Community countries
Get PDFGiven the concern of the meagre contribution of the manufacturing sector output in total GDP within the East African Community (EAC) member states, the purpose of this study was to in-vestigate whether growth rates in the manufacturing sector output of the five East African Com-munity member states can be explained by variations in the factors of input, productivity and governance. The study benchmarks the growth frameworks of neoclassical growth and its exten-sions, as well as the institutionalist growth theory, which guided the formulation of empirical growth models. Estimation is achieved by implementing first difference generalised method of moments (D-GMM) on a linear dynamic panel model through the specific-to-general modelling technique. Among the factors motivated by the neoclassical growth paradigm and its extensions, estimates from this study indicate that human capital and the gross capital formation input factors can help in predicting variations in manufacturing sector output growth in EAC member countries. Among the productivity factors, estimates show that higher lending rates and increased openness had a significant negative effect on the growth of the manufacturing sector among EAC member states. The productivity variables of foreign direct investment, inflation, domestic credit and financial deepening showed no ability to influence manufacturing sector growth in the EAC member states. Estimates further indicate that among the governance factors, control of corrupt-ion could help boost manufacturing sector output growth among EAC member states. Results from this study show that the governance variables of voice and accountability, and of regulatory quality, had an insignificant effect on the growth of manufacturing sector output among EAC member states. So the study shows that manufacturing sector output variations in EAC member states can partially be explained by the neoclassical and endogenous growth models, with little efficacy in the institutional growth model, suggesting the incompleteness of the growth frame-works adopted in assessing the sources of growth in manufacturing sector output in EAC mem-ber states. The study results suggest that the EAC member states can boost their manufacturing sector output growth by implementing policies and programmes that create incentives for more additions to capital stocks and improving the quality of human resources while equipping people with skills, establishng financial instituitions which offer access to cheap capital, like the East African Development Bank, and adopting import substitution growth strategies which could re-duce the quantity of imports and limit outflows of foreign exchange.Thesis (PhD) -- Faculty of Business and Economic Sciences, School of Economics, Development and Tourism, 202
Exploring the involvement of the SARS-CoV-2 Replicase in the synthesis of polyamines and heat shock proteins
No full textA disease named COVID-19 almost destroyed the human population. It is caused by the SARS CoV 2 virus which emerged in 2019 and rapidly spread worldwide forcing all countries to shut down. This virus uses non-structural proteins to complete its invasion and development inside the host. The non-structural protein 2 NSP2 defined as the RNA binding protein involved in coronavirus genome replication and decreases the human immune response is key for this virus’s development and invasion. It is believed that the NSP2 associate themselves with polyamines and heat shock proteins inside the host cell, to proceed with the viral development and this study aimed to investigate how SARS CoV 2 virus key non-structural proteins NSP2 utilizes polyamines and heat shock proteins using the molecular docking approach and molecular dynamics MD. In this present study a docking approach was used. The dockings were done on ClusPro, and analysis was done on Discovery Studio, chimera, and PyMOL. One of the enzymes that are involved in the regulation of polyamine biosynthesis, adenosylmethionine decarboxylase AdoMetDC was used in investigating the polyamine binding to the viral NSP2, and major heat shock proteins HSPs HSP40, HSP70, and HSP90 were used in the investigation of the binding of HSPs to viral non-structural proteins NSP2. The results obtained show that 32 interactions were formed when docking heat shock protein 40 HSP40 with the SARS CoV 2 NSP2, but the area that has the highest interactions was from amino acid Ala554 to His557. Asp553 plays a very crucial role in this interaction forming six interactions. Heat shock protein 70 produced about 28 interactions when docked with the SARS CoV 2 NSP2. But the section with the most bonds was from position 550 to 560 of the ligand. Human heat shock protein 90 HSP90 formed 19 interactions when docked with the SARS CoV 2 viral NSP2. MD revealed Arg458, Asn508, Met297, Arg301 and Tr417 active residues. And pharmacophore modeling indicated zinc inhibitors as crucial for inhibiting this virus. Enough interactions were produced with ideal bonds lengths, and it can be said that the functioning of the SARS CoV2 viral non-structural proteins functioning majorly depends on the presence of the heat shock proteins at hand for proper formation and depends on polyamines for complete development and correct functioning.Thesis (MSc) -- Faculty of Science and Agriculture, 202
End-user requirements of an assistive technology for profoundly Deaf parents with infants
Get PDFAs the number of deaf people in the world increases, the amount of parents who are deaf, is also growing. The world is increasingly relying on technology from which deaf parents can, and do, benefit significantly. Deaf parents are able to rely on available technology such as assistive technologies to overcome functional limitations. However, assistive technologies are often abandoned within a short period of time of being acquired. The abandonment of assistive technologies is believed to be due to a lack of proper elicitation of requirements. Therefore, the problem identified in this research is a lack of understanding of end-user requirements of an assistive technology for profoundly deaf parents with infants. A literature review together with logical argumentation was conducted and applied to identify and recommend a method suitable for eliciting end-user requirements for assistive technologies. Thereafter, an integrative literature review and thematic analysis was done to extract needs and challenges of profoundly deaf parents with infants, and group them according to themes that emerged. Finally, making use of the recommended method and the extracted needs and challenges of profoundly deaf parents with infants, twenty-eight end-user requirements of an assistive technology for profoundly deaf parents with infants were elicited. The twenty-eight elicited end-user requirements consist of eighteen end-user requirements that express functions of an assistive technology for profoundly deaf parents with infants, and ten end-user requirements that express an overall goal/objective to be attained by profoundly deaf parents with infants when the assistive technology is designed and developed. To evaluate the elicited end-user requirements, only the eighteen end-user requirements that express functions of an assistive technology for profoundly deaf parents with infants were considered. The evaluation was done by assessing both existing and emerging assistive technologies to understand the comprehensiveness of the eighteen elicited end-user requirements that express functions of an assistive technology for profoundly deaf parents with infants.Thesis (MIT) -- Faculty of of Engineering, the Built Environment and Technology, School of Information Technology, 202