61 research outputs found

    Ruthenium and Copper Complexes for Anti-Cancer and Catalytic Applications

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    Abstract This thesis details the synthesis, characterisation and evaluation of novel β-bis-ketoiminate ruthenium(II) and β-bis-ketoiminate copper(II) complexes for their biological and chemical applications. The anti-cancer, anti-bacterial and anti-fungal and catalytic activity of these complexes was investigated, with lead complexes undergoing further mechanistic investigations. Chapter 1 contains the background introduction to the project, through literature research of similar work as well as the aims of this project. Chapter 2 presents the synthesis and characterisation of novel β-bis-ketoiminate ruthenium(II) dicarbonyl complexes. 1H NMR, 13C {1H} NMR and detailed X-ray crystallographic data are given for this series of complexes. Chapter 3 introduces novel β-bis-ketoiminate copper(II) complexes, their synthesis and characterisation, with X-ray crystallographic data discussed. Chapter 4 introduces the MTT technique for assessing cytotoxicity, and discusses the anti-cancer activities of the series of complexes synthesised in Chapters 2 and 3. In addition, the chapter gives a brief literature review to anti-bacterial and anti-microbial studies, and the results of anti-bacterial and anti-fungal investigations on the β-bis-ketoiminate ruthenium(II) and copper(II) complexes. Chapter 5 presents the results of chemical investigations, hydrolysis and biomembrane, conducted on the two libraries of complexes. Chapter 6 contains a brief literature review on catalysis, and the results for transfer hydrogenation and Ullmann catalytic reactions on β-bis-ketoiminate ruthenium(II) complexes and β-bis-ketoiminate copper(II) complexes respectively. Chapter 7 contains experimental details and characterisation data for all the complexes synthesised within this thesis, and protocols for all the biological and chemical studies. Appendix presents a summary of X-ray crystallographic structure analysis for all the crystal structures reported within this thesis

    Let's talk about sex: a study of the impact of gender socialization on urban Shona youth sexuality in Harare, Zimbabwe

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    A research report submitted in partial fulfilment of the requirements for the degree of MASTER OF ARTS (HEALTH SOCIOLOGY) UNIVERSITY OF THE WITWATERSRAND May 2015Over the years, the studying of human sexuality has evolved from being strictly within the biological field, to being an area of interest within the social sciences. Looking at sexuality through a sociological lens in particular allows one to form a platform on which the relationships between culture, opinions about sexuality, sexual activity and good health can be understood. This study set out to explore the impact of gender socialization on sexual norms and behaviours, and the construction of sexuality amongst Shona speaking youth in Harare. Of particular interest was the level of sexual freedom that young women experience in modern times. Seven group discussions were held from a sample population which included urban, Shona speaking individuals between the ages of 19 and 25. The results showed that even though the norms passed to the youth through gender socialization sometimes have a limited effect, gender socialization still influences youth sexuality, thus failing to support the researcher’s initial assumption that sexual norms and behaviours are no longer influenced by Shona gender roles and norms which are passed to the youth through the socialization process

    The synthesis, characterization and reactivity of metallacycloalkanes and their precursors

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    Includes abstract.Includes bibliographical references.A series of bis(alkenyl)platinum(II) complexes of the type [PtL2{(CH2)nCH=CH2h](L2 = 1 ,3-bis( diphenylphosphino )propane and n = 3-6) have been successfully synthesized and characterized by IH, I3C and 31p NMR spectroscopy, elemental analysis and mass spectrometry. I3C NMR data for these complexes is herein presented for the first time. A new route for the synthesis of dicarbonyldibromide rhenium complexCp*Re(CO)2Br2 affording the product in very high yields is also herein reported

    Chemistry and speciation of potentially toxic and radioactive elements during mine water treatment

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    Philosophiae Doctor - PhDMine water poses a serious environmental challenge and contains elements such as Fe, Al, and Mn in potentially toxic concentrations. The major anion in mine water is sulphate. The complexity and diversity of mine water composition makes its treatment very expensive, and there is no “one-fits-all” treatment option available for mine water. Active treatment of mine water produces water with good quality but the processes are not sustainable because of the costs. Previous studies have shown that acid mine drainage can be treated with coal FA to produce better quality water. The use of coal FA, a waste material from coal fired power station and mine water would go a long way in achievement of sustainable treatment of mine water as per previous studies. In this study mine water and coal FA were characterized to determine their physiochemical properties. This study linked the modelling results obtained by using the Geochemist’s workbench (GWB) software to the results obtained during the actual treatment of Matla mine water and Rand Uranium mine water using coal FA and lime. The chemistry involved when Matla mine water and Rand Uranium mine water were treated with flocculants was also investigated. Lastly the chemistry and kinetics involved was investigated when mine water was treated with various ameliorants such as Matla coal FA, lime and/or Al(OH)3 using jet loop mixing or overhead stirring. Mine water from Matla coal mine had a pH of 8 and therefore was classified as neutral mine drainage (NMD). Rand Uranium mine water had a pH of less than 3 and therefore was classified as acid mine drainage (AMD). The concentration of sulphate, Na, Ca, Mg, B, Hg, Se and Cd ions in Matla mine water was 1475, 956, 70, 40, 15, 2.43, 1.12 and 0.005 mg/L respectively. The concentration of sulphate, Fe, Ca, Mn, Mg, Al, B, Cr, Pb, U, Cd, Se and As ions in Rand Uranium mine water was 4126, 896, 376, 282, 155, 27, 5.43, 3.15, 0.51, 0.29, 0.007, 0.06 and 0.006 mg/L respectively . These concentrations were above the target water quality range (TWQR) for potable water set by the Department of Water Affairs (DWA) and World Health Organization (WHO). The gross alpha radioactivity was 6.01 Bq/L and gross beta radioactivity was 6.05 Bq/L in Rand Uranium mine water

    The Significance of Strategic Control on the Growth of Churches in Harare, Zimbabwe

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    The research aimed to assess the effect of strategic control on the growth of churches in Harare, Zimbabwe. The research looked at the influence of strategic control on the growth on both Mainline and Pentecostal churches. The study followed a positivism philosophy, where an explanatory research design was applied. A multi-stage stratified random sampling was used to select the study participants who were adult congregants and church leaders from two strata, one stratum being made up of mainline churches and the other one by Pentecostal churches. Multi-stage stratified random sampling was deemed appropriate for the research as it ensured that there was representativeness within and across the strata. Data was collected from systematically selected congregants and church leaders in selected churches through interviewer-administered questionnaires using Open Datakit, a mobile data collection platform. Data analysis revealed that there was evidence of implementation of strategic control (mean score of 4) as part of strategic management practices in both Mainline and Pentecostal churches. Additionally, the findings show that strategic control influences the growth of churches (p-value <0.001). These findings showed that churches like any other organizations can be affected by the change in the socio-economic environment and thus they should implement appropriate strategies to remain viable and relevant. Strategic control plays a crucial role in ensuring that those strategies are effectively implemented. An effective Strategic Management Framework should be formulated and guide how churches can continuously control the implementation of their strategies to remain viable and achieve their mandate. Keywords: strategic control, church, church growth, strategic management DOI: 10.7176/EJBM/12-32-06 Publication date: November 30th 202

    Impact of Management Accounting on Decision Making: A Zimbabwean Perspective

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    The aim of the study was to assess the impact of management accounting practices on the decision-making process of the entity operating within the manufacturing sector using a case of Capadvise Foods and Logistics (Pvt) Ltd. The research study was based on the period from 2014 to 2017 which was majorly characterised by huge amounts of losses. Capadvise Foods experienced huge amounts of losses in spite of the existence of management accounting practices. This encouraged the researchers to seek out an in-depth insight on the impact of management accounting on decision making in light of such losses which were continually experienced. The researchers made use of questionnaires and interviews to collect qualitative and quantitative data about the opinions and attitudes of employees and management at Capadvise Foods regarding management accounting tools. The researchers found that management accounting tools contributed positively to the organisational decision making through provision, interpretation and analysis of data, enhancement in communication, relevant cost analysis and creation of budgets and forecasting. However, the researchers found that management accounting practices were compromised by technological advancement, organisational strategy, organisational factors and intensity of market competition. After analysing the results attained the researchers recommended for Capadvise Foods which include enrolling qualified management accounting staff, decision makers are allowed to make use of internal reports generated by management accountants and adoption of management accounting practices in order to allow proper and accurate decision making to take place

    A sociological understanding of contemporary child marriage in Mabvuku, Harare, Zimbabwe

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    Child marriage is a phenomenon that has been increasingly recognised as a global problem since the late nineteenth century. Since then, scholars across many disciplines along with various agencies such as government bodies and non-governmental organisations have tirelessly engaged in research exploring the causes and consequences of this practice and in developing prevention and mitigation strategies. These research efforts have been concentrated in some parts of the world and not others, with the findings in many cases being generalised problematically across different geographical areas. This thesis stands as a response to the dearth of academic research on child marriage in present-day Zimbabwe and simultaneously highlights the significance of studying the specificities of child marriage under particular historical and spatial conditions. The main objective of this thesis is to explore and understand child marriage as a part of modernday marriage practices in Zimbabwe, through a case study of child marriage in Mabvuku in Harare. In addressing this objective, it is hoped that new ways of thinking around this phenomenon will become evident. In addressing this main objective, the thesis considers the experiences of child brides, the drivers and consequences of child and post-child marriage experiences. It does this seeking to understand child marriage with reference to the types of marital unions which exist amongst Shona people in pre-colonial times and in post-colonial Zimbabwe. The thesis adopts a qualitative research methodology which involved in-depth semistructured interviews with 25 women in Mabvuku who were married before the age of 18, along with focus group discussions with community workers and interviews with pertinent government and non-government representatives. Due to certain challenges with current theorising about child marriage, there is an attempt to build theory by drawing upon in particular the Zimbabwean notion and practice of hunhu. A key conclusion is that child marriage in present-day Zimbabwe is in part a result of family transitions which arose during the time of colonialism and continue to this day

    A sociological understanding of contemporary child marriage in Mabvuku, Harare, Zimbabwe

    Get PDF
    Child marriage is a phenomenon that has been increasingly recognised as a global problem since the late nineteenth century. Since then, scholars across many disciplines along with various agencies such as government bodies and non-governmental organisations have tirelessly engaged in research exploring the causes and consequences of this practice and in developing prevention and mitigation strategies. These research efforts have been concentrated in some parts of the world and not others, with the findings in many cases being generalised problematically across different geographical areas. This thesis stands as a response to the dearth of academic research on child marriage in present-day Zimbabwe and simultaneously highlights the significance of studying the specificities of child marriage under particular historical and spatial conditions. The main objective of this thesis is to explore and understand child marriage as a part of modernday marriage practices in Zimbabwe, through a case study of child marriage in Mabvuku in Harare. In addressing this objective, it is hoped that new ways of thinking around this phenomenon will become evident. In addressing this main objective, the thesis considers the experiences of child brides, the drivers and consequences of child and post-child marriage experiences. It does this seeking to understand child marriage with reference to the types of marital unions which exist amongst Shona people in pre-colonial times and in post-colonial Zimbabwe. The thesis adopts a qualitative research methodology which involved in-depth semistructured interviews with 25 women in Mabvuku who were married before the age of 18, along with focus group discussions with community workers and interviews with pertinent government and non-government representatives. Due to certain challenges with current theorising about child marriage, there is an attempt to build theory by drawing upon in particular the Zimbabwean notion and practice of hunhu. A key conclusion is that child marriage in present-day Zimbabwe is in part a result of family transitions which arose during the time of colonialism and continue to this day

    Removal of sulphates from South African mine water using coal fly ash

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    Magister Scientiae - MScThis study evaluated SO4 2- removal from circumneutral mine water (CMW) collected from Middleburg coal mine using coal FA collected from Hendrina power station. The following parameters were investigated: the effect of the amount of FA, the effect of the final pH achieved during treatment, the effect of the initial pH of the mine water and the effect of Fe and Al on SO4 2- removal from mine water. The precipitation of ettringite at alkaline pH was evaluated to further reduce the SO4 2- concentration to below the DWAF limit for potable water. Removal of SO4 2- from mine water was found to be dependent on: the final pH achieved during treatment, the amount of FA used to treat the mine water and the presence of Fe and Al in the mine water. Treatment of CMW using different CMW:FA ratios; 5:1, 4:1, 3:1, and 2:1 resulted in 55, 60, 70 and 71 % SO4 2- removal respectively. Treatment of CMW to pH 8.98, 9.88, 10.21, 10.96, 11.77 and 12.35 resulted in 6, 19, 37, 45, 63 and 71 % SO4 2- removal respectively. When the CMW was modified by adding Fe and Al by mixing with Navigation coal mine AMD and treated to pH 10, 93 % SO4 2- removal was observed. Further studies were done to evaluate the effects of Fe and Al separately. Treatment of simulated Fe containing AMD (Fe-AMD) to pH 9.54, 10.2, 11.8, and 12.1 resulted in 47, 52, 65, and 68 % SO4 2- removal respectively. When Al containing AMD was treated to pH 9.46, 10.3, 11.5 and 12 percentage SO4 2- removal of 39, 51, 55 and 67 % was observed respectively.South Afric

    Impact of business confidence on private investments in South Africa

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    A wide range of theoretical and empirical studies have been carried out on various determinants of private investments in different economies. This dissertation specifically focuses on the impact business confidence on private investments with regards to the South African economy for the period between 1990 and 2014. The private investment sector in South Africa has, to a greater extent contributed to the overall GDP of the economy. Even though business confidence has a considerable impact on private investments, this study also took into consideration other variables that affect the private investment sector such as interest rates, exchange range and GDP To determine short-run and long-run relationships of business confidence on private Investments in South Africa, a vector error correction model was employed. In order to avoid spurious regression, the ADF test and the PP test were used to test for stationarity. Results of the study indicate that private investments are subject to permanent changes because of changes in business confidence. In addition to that, not all variables have a long-term relationship with private investments but business confidence has a significant long run relationship with private investment. After conducting an econometric analysis, results revealed that Business Confidence and Gross Domestic Product have a positive impact on private investments. On the other hand, interest rates and exchange rates have a negative impact on private investments in South Africa. Various policy recommendations were established on both Private Investments and Business Confidence
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