Which Black Lives matter? : a decolonial interrogation of xenophobia on Black South African Twitter
- Authors: McBrown, Anima
- Date: 2023-03-30
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/408930 , vital:70538
- Description: Thesis embargoed. To be released in 2025. , Thesis (MA) -- Faculty of Humanities, Journalism and Media Studies, 2023
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A critical analysis of Professor Andrew Tracey’s contribution to African music pedagogy and the field of applied ethnomusicology
- Authors: Moyo, Vuyelwa O'Lacy
- Date: 2022-10-14
- Subjects: Tracey, Andrew T N , Ethnomusicology , Music Instruction and study Africa , Mbira Zimbabwe
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/406829 , vital:70311
- Description: The research presented in this thesis is based on my interest and experience in forms of African music, ethnomusicology, and studying mbira with Professor Emeritus Andrew Tracey. When I arrived in South Africa in 2019 to join Rhodes University’s Applied Ethnomusicology programme, I chose to study the mbira with Tracey as the idea of learning more about Zimbabwe through music was important to the formation of my identity. Through the lens of embodied learning and a practice-based approach in this research, I evaluate how Tracey’s numerous contributions to African music pedagogy have improved prospects for African music scholars and students in terms of contributing to the goals of applied ethnomusicology. The primary purpose of this thesis is to respond to the absence of serious scrutiny of existing pedagogical approaches to African music at universities across South Africa. The contribution this research makes will be valuable to African music programmes across the continent as well as to practitioners of African traditional instruments, such as the marimba, mbira, timbila xylophones, nyanga pan pipes, and valimba xylophones. The thesis comprises five chapters. The first presents an introduction to the research, and its goals, procedures and approaches, along with an outline of the subsequent chapters. Tracey’s biography is covered in the second chapter. A consideration of the state of African music teaching in other African countries such as Ghana, Kenya, and Zimbabwe; the history of African music; and the state of African music pedagogy in tertiary institutions in South Africa constitutes the third chapter. Chapter 4 comprises an analysis of Tracey’s articles and data gathered from interviews, as well as my personal reflections as Tracey’s student. The final chapter presents a summary of the preceding chapters, the study’s findings, and suggestions for further research. A multidisciplinary approach was used for this thesis. The results finds that Tracey’s articles had six common themes which he wrote about and are a contribution to African music pedagogy. These themes are the history of instruments, the structure of the instrument, the learning/playing technique, structure of the instrument, transcription and dance steps. , Thesis (MMus) -- Faculty of Humanities, Music and Musicology, 2022
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Assessment of cytotoxic artemisinin and its derivatives as DNA damaging inducing agents in triple-negative breast cancer cells
- Authors: Mkhwanazi, Ntando
- Date: 2022-10-14
- Subjects: Breast Cancer , Artemisinin , DNA damage , Antineoplastic agents , Breast Cancer Treatment
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/362960 , vital:65378
- Description: In developing countries, including South Africa, breast cancer is the primary cause of cancer-related deaths among women. TNBC (triple-negative breast cancer) is an aggressive breast cancer subtype that is more prevalent in women of African descent. This subtype lacks the key receptors, namely the estrogen receptor (ER-), progesterone receptor (PR-), and human epidermal growth factor receptor 2 (HER2-) that are the basis of successful targeted therapies for other subtypes of the disease. To date, there are no effective, standardized targeted therapies for TNBC. Artemisinin is an anti-malarial drug and numerous derivatives of the compound have been developed to improve the potency and solubility of the parent compound. Artemisinin and its derivatives have gained attention as potential anti-cancer agents; however, such studies have not yet progressed to clinical trials and the precise mechanism of action of these compounds is yet to be fully explained. In this study, artemisinin, and its known derivative artesunate, as well as a novel derivative, WHN11, were investigated as DNA damage-inducing agents in TNBC. WHN11 was found to be the most potent of the three compounds, displaying an IC50 of 3.20 μM against HCC70 cells, artemisinin displayed an IC50 of 214.70 μM and artesunate displayed an IC50 of 25.48 μM. The compounds were less toxic to the MCF12A non-cancerous cells, with IC50 values 298.30, 87.53, and 8.35 μM for artemisinin, artesunate, and WHN11, respectively, and displayed selectivity indices of 1.39, 3.44 and 2.61 μM for artemisinin, artesunate, and WHN11, respectively. In silico and in vitro studies revealed that the artemisinin compounds bind to DNA through the minor groove. While all three compounds were able to bind to DNA, a comet assay revealed that only artemisinin and artesunate, and not WHN11, were able to cause DNA damage compared to the vehicle control, DMSO. Finally, a topoisomerase I (TOPO I) enzyme assay demonstrated that while the compounds appeared to display a degree of inhibition of TOPO I, as evidenced by a downward shift in the plasmid band on the agarose gel, they were not able to fully inhibit the enzyme to return the plasmid to the supercoiled conformation. In addition, combination studies revealed that artemisinin, artesunate, and WHN11 acted synergistically in combination with camptothecin, but displayed either an additive (artemisinin) or antagonistic (artesunate and WHN11) relationship when used in combination with etoposide. In conclusion, artemisinin, its known derivative artesunate, and novel and highly toxic derivative WHN11, all bind to DNA via the minor groove, however only artemisinin and artesunate, and not WHN11, cause DNA damage, indicating a potentially different mechanism of action of the three artemisinins. All three compounds act synergistically with camptothecin, which suggests interference with topoisomerase activity, partially supported by slight inhibition of TOPO I activity, and could indicate either direct inhibition of the enzyme or interference with enzyme function by competitive binding to the DNA. Further studies could help explore alternate DNA damage assays, to validate these findings, and the effect of the compounds on TOPO II activity could also be assessed. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2022
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Conceptualising mental distress from an African psychology paradigm: using an interpretative phenomenological analysis of the views of traditional healers
- Authors: Nabo-Bazana, Sandisiwe Sifanelwe
- Date: 2022-10-14
- Subjects: Healers South Africa , Traditional healer , Mental distress , Black psychology , Afrocentrism
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/406213 , vital:70249
- Description: With South Africa's long history of colonialism and racial oppression, there are still services in the country that many South Africans cannot relate to, including psychology. Research shows that many South Africans experience and are affected by mental distress due to several factors, including poverty, unemployment, and traumatic experiences. Managing and treating such distress has always been challenging for most South Africans. Some debates question the relevance of psychological services from the West in a South African context. This study explores other approaches to psychology that look beyond the Biopsychosocial model when dealing with certain types of disorders in an African context. African psychology, or the Afrocentric approach, looks at what is beneath the surface, not just the presenting problem. Mainstream psychology strives to be universal and applicable to all. However, African psychology disagrees with this notion. African psychology perceives human beings as strongly influenced by social and cultural influences. The focus of this approach includes the spiritual realm and the attached meanings. There is evidence for the need to merge Traditional and Western medicine. The research methodology for this study is qualitative, using Interpretative Phenomenological Analysis. IPA allows for a critical engagement with the ways in which participants construct their reality. The researcher carried out semi-structured interviews to enable participants, all traditional healers (3 female and 2 male), to narrate their experiences dealing with mentally distressed clients. The accounts of these traditional healers were analysed focusing on people who have experienced mental distress. From the analysis and synthesis of the themes, findings illustrate how traditional healers conceptualise and construct mental distress from an African Psychology paradigm. An emerging core theme was the importance of the divine call and its influence on the chosen treatments. More studies are needed to illustrate the potential for collaboration between African Traditional healing and EuroAmerican healing practices, to provide holistic services to people in need. , Thesis (MA) -- Faculty of Humanities, Psychology, 2022
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Development and optimisation of a qPCR assay for the enumeration of Cryptophlebia leucotreta granulovirus (CrleGV) used for commercial applications
- Authors: Mela, Thuthula
- Date: 2022-10-14
- Subjects: Cryptophlebia leucotreta granulovirus , Cryptophlebia leucotreta , Late expression factor 8 (LEF-8) , Late expression factor 9 , Dark field microscopy , Genomic DNA , Polymerase chain reaction , Plasmids
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/362949 , vital:65377
- Description: The citrus industry contributes significantly to the South African agricultural sector. Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae) is highly important to the South African citrus industry as it is classified as a phytosanitary pest by most international markets. Thaumatotibia leucotreta has caused an estimated annual loss of up to R100 million to the industry. In order to control T. leucotreta in South Africa, an integrated pest management (IPM) programme has been used. One of the components of this programme is Cryptophlebia leucotreta granulovirus (CrleGV), which has been formulated to a registered biopesticide namely Cryptogran and has been successfully applied in the field for over 15 years. To use CrleGV as biopesticides, quantification of the viral particles is required to perform bioassays for field trials and formulation, among other applications. Darkfield microscopy is a traditional method used for the quantification of CrleGV; however, the method is characterised as being subjective, tedious, labour intensive, and time-consuming. This study aims to develop and optimise a qPCR technique to accurately quantify CrleGV-SA OBs using plasmid DNA for downstream applications. Firstly, lef-8, lef-9, and granulin conserved genes from CrleGV-SA and CrleGV-CV3 genome sequences were analysed by performing multiple alignments to evaluate the degree of identity between these genes. This was done to design two sets of oligonucleotides (internal and external) from regions with the highest identity. Subsequently, in silico testing was done to evaluate the designed oligonucleotides to determine whether they specifically bind to the selected target regions. Secondly, three sets of DNA plasmids (pJET1.2-Gran, pJET1.2-lef-9, and pJET1.2-lef-8) were constructed, each containing a target region for either granulin, lef-9, and lef-8 genes for use as standards in a downstream qPCR assay. This was achieved by first extracting gDNA from CrleGV-SA OBs and using the gDNA as a template to PCR amplify the target regions of the selected gene regions with the designed oligonucleotides. Subsequently, the PCR amplified regions were then directly ligated into the pJET1.2/blunt vector, and the plasmids were confirmed by colony PCR, restriction enzyme digestion, and Sanger sequencing. Thirdly, two different methods of CrleGV-SA gDNA extraction were compared to determine which method has the best yields in terms of concentration. The extraction methods compared were the Quick-DNA Miniprep Plus kit according to manufacturer’s instructions (Method 1a), pre-treatment with Na2CO3 prior to using the Quick-DNA Miniprep Plus kit (Method 1b), pre- treatment with Na2CO3, and neutralisation with Tris-HCl prior to gDNA extraction using the Quick-DNA Miniprep Plus kit (Method 1c) and the CTAB method (Method 2). The gDNA concentration and purity for all samples were determined using a Nanodrop spectrophotometer. Method 1c (Na2CO3 and Tris-HCl pre-treated plus Quick-DNA Miniprep Plus kit) was the most efficient at extracting genomic DNA compared with the other methods, resulting in the highest DNA concentration in short processing time. Fourthly, plasmid standards were evaluated for use in the qPCR assay. This was done as it was important to consider the efficacy of the oligonucleotides; including the ability of the oligonucleotides to anneal to the appropriate segment of DNA without extensive formation of oligonucleotides dimers, non-specific annealing, or formation of secondary structure. In addition, it was done to ensure that highly accurate standard curves were generated. The standard curves were to be utilised in the downstream qPCR assay to determine the quantity of test samples by interpolation, reading from the values within the standard curve. Lastly, darkfield microscopy and qPCR methods of enumeration were compared to verify their accuracy and determine the most consistent and comparable method. This was achieved by quantifying the purified, crude-purified, and viral formulated CrleGV-SA suspensions using these methods. Subsequently, a statistical analysis was conducted to compare the results produced by the two enumeration methods. The obtained results showed that the granulin, lef- 8 and lef-9 qPCR values did not significantly differ from the darkfield microscopy results. The findings of this study revealed that the two assays, lef-8 qPCR and lef-9 qPCR, were more robust, sensitive, and efficient for the quantification of CrleGV-SA. Thus, this study has successfully developed a qPCR assay that is comparable with the traditional darkfield microscopy counting technique. This is the first study to use the qPCR technique to enumerate CrleGV-SA using plasmid standards. The developed qPCR assay is reliable, rapid, and cost- effective and has a great potential to be used as an alternative method to darkfield microscopy in the laboratory and commercial settings. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2022
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Linking Hop and LANA1 in the KSHV life cycle
- Authors: Ruck, Jamie-Lee
- Date: 2022-10-14
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/365291 , vital:65724
- Description: Thesis embargoed. Possible release date set for early 2025. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2022
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The development, formulation and characterization of an optimized metronidazole loaded solid lipid nanoparticle formulation for ocular drug delivery
- Authors: Sikhondze, Simise Siphelele
- Date: 2022-10-14
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/403014 , vital:69914
- Description: Thesis embargoed. To be released early 2026. , Thesis (MSc) -- Faculty of Pharmacy, Pharmacy, 2023
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A retrospective study of antimicrobial prescribing practices in paediatric patients at the Mahalapye District Hospital, Central Botswana
- Authors: Nyawera, Angella
- Date: 2022-04-06
- Subjects: Anti-infective agents Botswana Mahalapye , Drug resistance , Pediatrics Botswana Mahalapye , Pediatrics Formulae, receipts, prescriptions , Drugs Prescribing Moral and ethical aspects
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/290682 , vital:56774
- Description: Background: The development of antimicrobial resistance (AMR) has been linked to the increased and irrational use of antimicrobial medicines. The aim of this study was to investigate the antimicrobial prescribing practices in the paediatric medical ward at Mahalapye District Hospital (MDH) in Botswana and to determine whether antimicrobial stewardship (AMS) measures were being implemented at the hospital. Methods A cross-sectional, descriptive, mixed methods, observational approach was taken in this study. The study site was the paediatric medical ward (PMW) at MDH. Information about the antimicrobials prescribed for paediatric patients from January 2018 to December 2018 was collected from patients’ information files and compared to national antimicrobial prescribing guidelines to determine prescribers’ adherence. Qualitative semi-structured interviews were conducted with members of staff at MDH to determine whether antimicrobial stewardship (AMS) measures were adopted at the hospital. Results A total of 278 patients were included in this study, 12 of these were admitted twice during the study period. In total 290 admissions were analysed, with 659 antimicrobial medicines prescribed. The most common diagnoses were pneumonia (36.9%), acute gastroenteritis (20.7%), upper respiratory tract infections (3.4%), and bronchiolitis (3.1%). The most prescribed antimicrobials were ampicillin (21.4%), gentamicin (21.2%), and cefotaxime (8.3%). Adherence to guidelines was relatively good, with 82.7% of antimicrobials prescribed for the patients in the study having been prescribed in compliance with the national prescribing guidelines. The semi-structured interviews highlighted the fact that staff knew about AMS and AMR in general, however awareness of an AMS committee at MDH varied. The AMS committee was a multidisciplinary committee, which was a subcommittee of the Drugs and Therapeutics Committee (DTC). Discussion and Conclusion The results suggest that adherence to prescribing guidelines was relatively high compared to other paediatric antimicrobial utilisation studies in African countries. Prescribing of antimicrobial medicines was consistent with other African countries. The long period of time that it takes for microbiological test results to become available means that most prescribers rely on empirical prescribing. The antimicrobial committee is a multidisciplinary committee with defined roles for its members, consistent with international guidelines for implementing an AMS committee at a hospital. , Thesis (MPharm) -- Faculty of Pharmacy, Pharmacy, 2022
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Rainwater and alternative potable water microbial water quality and DRM implications in Makana Local Municipality
- Authors: Nhokodi, Tererai
- Date: 2022-04-06
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/232227 , vital:49973
- Description: Thesis (MSc (Pharm)) -- Faculty of Pharmacy, Pharmacy, 2022
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Stock market volatility during times of crisis: a comparative analysis of the conditional volatilities of JSE stock indices during the 2007/08 global financial crisis and COVID-19
- Authors: Wang, Zixiao
- Date: 2022-04-06
- Subjects: Stock exchanges , Johannesburg Stock Exchange , Global Financial Crisis, 2008-2009 , COVID-19 (Disease) Economic aspects , Economic forecasting , Stock exchanges and current events , GARCH model
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/284603 , vital:56078
- Description: This research analyses the comparative behaviour of stock market volatility during two crises. The goal of this research is to determine whether assumed cyclical and defensive sectors have either retained or revealed their expected properties during both the Global Financial Crisis (GFC) and COVID-19 by analysing sectoral volatility amid these two crises. Understanding how volatility changes amid crises helps to determine whether the volatility assumptions of diversified investment portfolios for both defensive and cyclical sectors still held given the different causes of each crisis. In turn, this knowledge can assist with risk management and portfolio allocation in stock market investments. The study can also contribute towards the enhancement of financial markets’ resistance against systemic risks through portfolio diversification, and aid government decision-making targeted at tackling the weaknesses of different economic sectors especially in times of overall economic weakness. This research makes use of the GARCH model to analyse a group of daily time series that consists of eleven sectoral indices and one benchmark index, all based on the South African stock markets. These observed series are categorised into two full sample periods, one designated to the Global Financial Crisis (January 2006 to May 2009) and the other for COVID-19 (January 2018 to May 2021). These are further divided into two sets of sub-sample periods, each made up of a pre-crisis and during-crisis. Furthermore, the dummy variables representing the occurrence of structural breaks are inserted into the full sample periods’ conditional variance equations. This is aimed at capturing the asymmetrical impact of the crises themselves on all observed series. Based on the movement of volatility persistency from pre-crisis to during-crisis for both crises, the results show that, firstly, Health Care and Consumer Goods are considered defensive Sectors. Secondly, Banks, Basic Materials, Chemicals, Telecommunications, and Financials are considered cyclical Sectors. Thirdly, Automobiles & Parts, Consumer Services, and Technology are considered indeterminable Sectors due to the inconsistent behaviour of these sectors’ volatility persistency throughout the sub-sample periods of both crises. Overall, according to the average volatility persistency, the observed series for COVID-19’s full sample period are generally less volatile than those of the GFC. However, the sub-sample periods suggest that the observed series for both pre-crisis and during-crisis periods of COVID-19 are more volatile than those same sub-samples of the Global Financial Crisis. Being able to analyse the characteristics of stock market sectors is crucial for risk management and optimal portfolio allocation of stock market investments. This can be achieved through portfolio diversification by investing in a variety of stocks, both cyclical and defensive, and adjusted over time based the needs of stock market investors. Diversified portfolios do not only serve the interests of individual investors, but can also enhance the financial markets’ overall resistance against systemic risks. , Thesis (MCom) -- Faculty of Commerce, Economics and Economic History, 2022
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The impact of urban gardening on household food security: evidence from Makhanda East, Eastern Cape Province, South Africa
- Authors: Bruwer, Guillaume Marcel Xavier
- Date: 2022-04-06
- Subjects: Food security South Africa Makhanda , Urban agriculture South Africa Makhanda , Urban gardening South Africa Makhanda , Sustainable development South Africa Makhanda , South Africa Economic conditions , Subsistence farming South Africa Makhanda , Economic impact analysis South Africa Makhanda , Propensity Score Matching (PSM)
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/263575 , vital:53640
- Description: Urban gardening in townships is a common coping strategy employed by poor inhabitants to improve food security, earn income through sales, and generate cost-savings through home consumption of fresh produce. Food security is a cornerstone of human development and welfare, and the achievement thereof remains a global challenge. The majority of academic research and policy documentation traditionally positions food insecurity as a rural phenomenon. However, recent trends point to an increase in food insecurity in urban areas, particularly in low-income areas such as townships. In South Africa, rapid urbanization has led to burgeoning townships and rapidly expanding low-income informal settlements characterised by poverty, unemployment, and food insecurity. Research concerned with the role that urban agricultural production plays in contributing to the food security of poor households is scarce and not well understood. This research, therefore, aimed to contribute to the limited research which specifically examines urban food security, and the role urban agriculture play in the achievement of household food security. The study employed collective action theory and utility theory to firstly provides an in-depth examination of the determinants of participation in urban gardening using Probit regression modeling. The second research objective was to perform an impact evaluation of participation in urban gardening on selected household food security indicators including Household Dietary Diversity Scores (HDDS), the Household Hunger Scale (HHS) and the Coping Strategy Index (CSI) using Propensity Score Matching (PSM). Purposive and snowball sampling methods were employed to obtain a sample of 60 urban gardeners and a control group of 55 non-gardening households from Extension 6, 7 and 10 townships as well as Joza Location in Makhanda East, Eastern Cape Province. Households were surveyed using a structured household food security questionnaire. A focus group discussion was held with the Linomtha Community Garden members and key informant interviews were undertaken with important stakeholders such as the local extension officers. Descriptive analysis revealed that urban gardening households (UGs) had older household heads who were less educated, and that land and water availability were the dominant constraints to increases in agricultural production. Results from the probit and average marginal effects models showed that the likelihood of participation significantly increased when household unemployment and dependency increased and that households who were engaged in off-farm economic activity were more likely to participate in urban gardening. The impact evaluation was performed using PSM and Average Treatment Effect on the Treated (ATT). Analysis illustrated that participation in urban gardening does significantly reduce both the full CSI and Reduced CSI. Thus, participation in urban gardening improves the food security of participating households by significantly reducing the frequency of participating households (UGs) applying undesirable coping strategies such as sending children elsewhere other than the household, borrowing food from other households and reducing the number of meals eaten in a day due to food shortages. This study posits that urban gardening alone will not eradicate the rampant food insecurity and poverty which pervades in South Africa’s townships. However, urban gardening participation does contribute to the construction of a sustainable, urban livelihood by reducing the number and severity of the undesirable coping strategies that food insecure households employ by providing some nutritious produce as well improved social capital through gardening networks and supporting institutions. It is recommended that policy makers, at a national and municipal level, need to create a clearer directive for the integration of urban food production into the urban food marketplace thus increasing access to income generating channels for small-scale home, and community gardeners. Co-operation between private and public institutions for food security and urban gardeners needs to be fostered and awareness of opportunities to participate in urban gardens needs to be improved. Central to the developmental challenges that rapid increases in urbanization and food insecurity in poor urban areas, is the need for national and local governments to improve access to economic opportunities in township areas - both in urban agriculture and in other, skills intensive sectors. , Thesis (MEcon) -- Faculty of Commerce, Economics and Economic History, 2022
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Transfer pricing: an analysis of legislation in the southern African Customs Union
- Authors: Patel, Nabil Ahmed
- Date: 2022-04-06
- Subjects: Transfer pricing
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/241482 , vital:50943
- Description: Transfer pricing is defined as the setting of the price for goods sold and services rendered between related entities. For example, if a subsidiary company sells goods or renders services to its holding company or a sister company, the price charged is referred to as the transfer price. Transfer pricing can be used to manipulate profits and facilitate tax evasion. Therefore, it is important that countries enact transfer pricing legislation to prevent this. The United Nations (UN) and Organisation for Economic Co-operation and Development (OECD) guideline documents form the basis for most global legislation and conventions dealing with transfer pricing. The over-arching goal of this research was to investigate whether transfer pricing legislation in the Southern African Customs Union (SACU) aligns between SACU countries and with the OECD Guidelines and the UN Manual. The research applied a legal interpretive doctrinal research methodology and a qualitative research method. The data comprised primary legislation in the SACU countries, transfer pricing guidelines issued by revenue authorities in the SACU, OECD Guidelines, the UN Manual and journal articles. It was found in this study that certain aspects of transfer pricing legislation in the SACU are not fully aligned to each other and to the OECD Guidelines and the UN Manual. This study proposed recommendations to improve transfer pricing legislation in the SACU. These improvements include the introduction of transfer pricing legislation in Eswatini and Lesotho, and updating transfer pricing legislation in Namibia and South Africa in terms of the latest versions of the OECD Guidelines and the UN Manual. , Thesis (MCom) -- Faculty of Commerce, Accounting, 2022
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Design, synthesis, characterization and evaluation of Chitosan-based hydrogel for controlled drug delivery system
- Authors: Safari, Justin Bazibuhe
- Date: 2022-04
- Subjects: Chitosan , Drug delivery systems , Drugs Controlled release , Tenofovir , Colloids , Hepatitis B Chemotherapy , Hydrogel
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/232182 , vital:49969
- Description: Hepatitis B infection is a deadly infectious disease caused by the hepatitis B virus and is responsible for many deaths every year worldwide. Despite medication and vaccines against hepatitis B infection, it still presents high morbidity and mortality among populations. This is partly due to factors such as a long medication period of the existing treatments, resulting in poor patient compliance and leading to treatment failure. In addition, this situation can be responsible for the observed emerging drug resistance. Hence, novel drugs and drug delivery systems are needed to tackle this matter. Many strategies have been used to develop long-acting drug delivery systems treatment for several infectious diseases. Hydrogel drug delivery systems have shown interesting results as controlled drug delivery systems for several drugs. Therefore, the present study aimed to develop chitosan grafted poly (acrylamide-co-acrylic acid) hydrogel and apply it as a pH-sensitive controlled delivery system of tenofovir disoproxil fumarate (TDF). TDF is a nucleoside reverse transcriptase inhibitor used as first-line treatment of hepatitis B chronic infection and in the treatment of other viral infections. The free-radical polymerization method was utilized to modify chitosan by grafting acrylamide and acrylic acid and using N, N’-methylene bisacrylamide as the crosslinking agent to prepare the hydrogel, followed by an optimization of parameters that could affect the swelling capacity. The prepared chitosan-g-poly(acrylamide-co-acrylic acid) hydrogel was characterized using Fourier Transmission Infra-red spectroscopy (FTIR), X-Ray Diffraction (XRD), Thermal Gravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), Energy-dispersive X-ray spectroscopy (EDS), Scanning Electron Microscopy (SEM), and was evaluated for cytotoxicity using a HeLa cell assay. TDF was used as a drug model, it was loaded by the swelling equilibrium method, following by the investigation of the release profile of TDF-loaded hydrogel at pH 1.2 and 7.4. A successful synthesis of chitosan grafted poly(acrylamide-co-acrylic acid) hydrogel was confirmed by Fourier Transmission Infra-red spectroscopy (FTIR), X-Ray Diffraction Spectroscopy (XRD), Thermal Gravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), Energy-dispersive X-ray spectroscopy (EDS) and Scanning Electron Microscopy (SEM). Optimization results showed that the ratio of monomers impacted the swelling ratio of the hydrogel and both the concentration of the crosslinking agent, and the reaction initiator also affected the swelling ratio. The synthesized hydrogels were sensitive to pH and ionic strength. Hydrogel swelling was lower in acidic solutions and higher in neutral and basic solutions and decreased with the increasing ionic strength. Furthermore, SEM results revealed that hydrogel have a rough and fibrous surface structure with numerous pores. Cytotoxicity studies demonstrated that the hydrogel was non-cytotoxic at 50 μg/ml against HeLa cells which suggested a good biocompatibility of the material. TDF was loaded and released from the hydrogels and showed an encapsulation efficiency and drug loading percentage ranging from 81-96% and 8-10%, respectively. TDF release profile was found to be low in buffer solution of pH 1.2 (in the range of 5-10%) and much higher (38-53%) at pH 7.4 within 96 hours. TDF maintained its chemical integrity after release and the hydrogels can therefore be proposed as a new controlled-release drug delivery system for hepatitis B treatment. , Thesis (MSc) -- Faculty of Science, Chemistry, 2022
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