Walter Sisulu University
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Biogenic synthesis of Silver nanoparticles (AgNPs) and its effects on Zebrafish (Danio rerio)
Get PDFThe increase in use and production of engineered nanoparticles in recent years points towards their inevitable release into freshwater ecosystems. Subsequently, exposure to organisms in freshwater ecosystems is to be expected. The aim of this dissertation was to synthesize silver nanoparticles (AgNPs) using silver nitrate, gelatine and maltose as precursor, capping and reducing agent respectively. Cytotoxic effects of the as-synthesized AgNPs was evaluated at concentrations of 0.031 μg/L, 0.250 μg/L and 5.000 μg/L on selected target organs in zebrafish (Danio rerio ) after 96 hr of exposure, under a 24 hr static renewal system. Formation of AgNPs was investigated by UV-Vis spectrophotometry, which displayed absorption maxima peak characteristic of plasmon resonance band for silver at 419 nm. From transmission electron microscopy, AgNPs was found to be small, well dispersed and spherical in shape with a narrow size distribution, and an average particle size of3.76 ± 1.00 nm. Histopathological alterations following exposure to AgNPs was noticed in the gills, epidermis, muscle tissue and kidney. Secondary lamellae hypertrophy, oedema and epithelial lifting was observed in all experimental groups. Curling and clubbed tips of secondary lamellae were observed at the lowest concentration (0.031 μg/L). Hyperplasia and lamellae fusion was most common at the median concentration (0.250 μg/L) of AgNP exposure. Hypertrophy of endothelial cells along with blood vessel congestion was also observed. Reduced secondary lamellar length, lamellar erosion and thinning were observed at the highest concentration (5.000 μg/L).AgNP exposure also altered the shape of alarm cells. In addition, hyperplasia and hypertrophy of goblet cells were observed at the highest concentration (5.000 μg/L) at 96 hr. At 5.000 μg/L of AgNP, PAS reaction was intense (deep purple), while the number and size of these cells decreased. Staining with AB pH 2.5 demonstrated an intense deep purple staining at the lowest and at the median concentration (24 hr). Moderate staining was seen at the higher concentrations. Muscle bundles with severe oedema, their thickening and separation were more pronounced in all treated groups. Histopathological tubular deformation and mononuclear cell infiltration were observed in kidney tissues. In addition; an increase in melano‐macrophage aggregation intensity was identified on the 48 hr in the treated groups. An increase in tubular epithelial cell regeneration/ proliferation, resulting in production of new epithelial cells which was indicative of recovering of kidney tissues from AgNP induced injury at 96 hr of exposure. Results presented here shows that fish respond to the presence of AgNPs
Inequality in uptake of isoniazid prevention therapy and Mantoux test among pregnant women with HIV in the Eastern Cape, South Africa
Get PDFDistorted, Relegated and Colonised: Reconceptualising Ogun as the God of Justice in Sunnie Ododo’s Hard Choice
Get PDFThe effort to name and ascribe duties to African gods using Eurocentric knowledge can lead to violence, hence causing them to be tagged negatively. Due to the imperial distortion of African history, the people were made to believe that they need civilisation, salvation, and reconstruction. The colonisers had to convince Africans that all that emanated from the continent was filled with ‘darkness’ and therefore needed to be civilised, reconstructed and humanised by Europe. African myths and religions suffer from this deceptive move by the Europeans and the gods are often relegated to being wicked and unjust. In this paper, which attempts to correct such erroneous beliefs, the focus is on Ogun, the Yoruba god of war, who has been subjected to mistaken identity by scholars, researchers and critics. It is against this backdrop and misrepresentation of Ogun that the authors delink from the notion that the god is a vengeful and obstinate god. They conclude that Ogun is not a god who engages in reckless devastation of life, as is commonly argued in literature criticisms of the Ogun figure, but a god who seeks justice when wronged. Decolonial thought and its view on ‘unthinking’ Eurocentric epistemologies on Africa are used to unpack Ogun’s characteristics as a god of justice in Ododo’s Hard Choice
Barriers Inhibiting The Implementation Of Gender Equity And Accessibility Of Female Teachers To Management Positions In Oliver Reginald Tambo Inland District
Get PDFThe purpose of the study was to examine the barriers inhibiting the implementation of gender equity and accessibility of female teachers to management positions. This study was conducted in the OR Tambo inland, which is one of the Education Districts in the Eastern Cape Province of South Africa. It should be noted that in terms of intelligence, requisite skills to influence and motivate the workers to accomplish the organisational goals is not linked to gender. It is for this backdrop that motivated me to examine the factors prohibiting and limiting thereof the females from being offered and occupy the management positions in most organisational institutions. This study is aimed to promote a paradigm shift and transformation in overlooking the gender equity by the role-players in the societies and various institutions. Furthermore, the study intends to promote the awareness to stake holders and enactment that the management positions are for everyone who possesses the leadership and management skills. The feminist and social constructivism theories were employed in engaging with the literature reviewed in this research. The survey research design was adopted in this study. A mixed methods research was used to gather and analyse the collected data. Principals, deputy principals and heads of departments were the target population from which the sample was drawn. There were 90 subjects from which data were collected, where 78 were subjected to questionnaires while 12 of them were interviewed. The sample was purposefully selected from 4 high schools that are geographically located in the OR Tambo inland: one from circuit 9, one from circuit 11 and two from circuit 3 schools. The tools used for the gathering of the data were questionnaires, observation and interviews. The analyses of the two data sets were done separately and later put together for discussion. This implies that sequential data analysis was performed. Qualitative data were analysed using content analysis. The quantitative data collected through questionnaire were analysed by using valid percentages, and tables generated by the Statistical Package for Social Sciences (SPSS). The use of SPSS helped me to summarise the collected quantitative data in examining the relationships of variables towards the problem under study. The descriptive and inferential statistics were considered for quantitative data analysis. Upon the completion of the quantitative data analyses, the qualitative data were analysed using content analysis. The findings from this study reveal that the social and cultural stereotypes of female managers; females’ lack of capacity and motivation; male dominance and cultural perceptions/beliefs; union and school governing bodies (SGBs) interference and institutional policies are barriers inhibiting the implementation of gender equity and accessibility of female teachers to management positions. Based on the emerged findings, it is recommended that policy-makers, the administration officers and immediate supervisors encourage the panellists for short-listing and interviews to comply with the legislative that requires the transformation and adherence to gender equity in all recruitment processes and practices. It is also recommended that workshops about the compliance on the implementation of gender equity by the role-players in education sector are widely and often conducted. It is further recommended that through distribution of circulars and school newsletters, conducting of imbizo or the role-players about the adherence to gender equity and constant dialogue with the communities, teacher’ unions, parents and youth in meetings could improve their perceptions and understanding that management positions for employees should be based on efficiency, competence and professional qualification but not on gender perspective.Thesis (D.Ed) -- Faculty of Education Sciences, 201
Anticholinesterase and Antioxidant Activities of Spilanthes filicaulis Whole Plant Extracts for the Management of Alzheimer’s Disease
Get PDFBackground: Spilanthes filicaulis is a tropical herb implicated as a memory enhancer in ethnomedicine. Objective: The study investigated acetyl/butyryl cholinesterase inhibitory and antioxidant activities of different extracts of S. filicaulis whole plant and correlated them to its phytochemical constituents. Methods: The powdered whole plant was successively extracted with n-hexane, ethyl acetate and methanol. Acetyl cholinesterase (AChE) and Butyryl cholinesterase (BuChE) inhibitory activity were evaluated by Ellman colorimetry assay. Antioxidant activity was tested using 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, ferric reducing power and nitric oxide scavenging assays. Total phenolic, flavonoid and tannin were estimated using standard methods. Correlation was determined using Quest Graph™ Regression Calculator. Results: Various extracts exhibited concentration-dependent AChE and BuChE inhibitory activity with ethyl acetate extract being the highest with IC50 of 0.77 μg/mL and 0.92 μg/mL for AChE and BuChE respectively. The ethyl acetate extract also showed the highest reducing power when compared with the other extracts. The methanol extract had slightly higher phenolic and flavonoid content and showed the highest DPPH radical scavenging effect. DPPH scavenging, AChE and BuChE inhibition had high correlation with the total flavonoid content with R2 values of 1.00, 0.800 and 0.992 respectively while nitric oxide scavenging had high correlation with phenolics and tannins with R2 = 0.942 and 0.806 respectively. Conclusion: These results show that the extracts of the whole plant of S. filicaulis possess significant AChE/BuChE inhibitory and antioxidant properties, mostly due to its flavonoid content, suggesting the possible use of the plant in neurodegenerative diseases such as AD
Ursolic Acid and its derivatives as bioactive agents
Get PDFNon-communicable diseases (NCDs) such as cancer, diabetes, and chronic respiratory and cardiovascular diseases continue to be threatening and deadly to human kind. Resistance to and side effects of known drugs for treatment further increase the threat, while at the same time leaving scientists to search for alternative sources from nature, especially from plants. Pentacyclic triterpenoids (PT) from medicinal plants have been identified as one class of secondary metabolites that could play a critical role in the treatment and management of several NCDs. One of such PT is ursolic acid (UA, 3 β-hydroxy-urs-12-en-28-oic acid), which possesses important biological effects, including anti-inflammatory, anticancer, antidiabetic, antioxidant and antibacterial effects, but its bioavailability and solubility limits its clinical application. Mimusops caffra, Ilex paraguarieni, and Glechoma hederacea, have been reported as major sources of UA. The chemistry of UA has been studied extensively based on the literature, with modifications mostly having been made at positions C-3 (hydroxyl), C12-C13 (double bonds) and C-28 (carboxylic acid), leading to several UA derivatives (esters, amides, oxadiazole quinolone, etc.) with enhanced potency, bioavailability and water solubility. This article comprehensively reviews the information that has become available over the last decade with respect to the sources, chemistry, biological potency and clinical trials of UA and its derivatives as potential therapeutic agents, with a focus on addressing NCD
Enhancing Teacher Support for the effective implementation of inclusive education: A case of selected Districts in South Africa
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