List of Titles

Structural bioinformatics studies and tool development related to drug discovery

Authors: Hatherley, Rowan
Date: 2016
Subjects: Structural bioinformatics , Drug development , Natural products -- Databases , Natural products -- Biotechnology , Sequence alignment (Bioinformatics) , Malaria -- Chemotherapy , Heat shock proteins , Plasmodium falciparum
Language: English
Type: Thesis , Doctoral , PhD
Identifier: vital:4164 , http://hdl.handle.net/10962/d1020021
Description: This thesis is divided into two distinct sections which can be combined under the broad umbrella of structural bioinformatics studies related to drug discovery. The first section involves the establishment of an online South African natural products database. Natural products (NPs) are chemical entities synthesised in nature and are unrivalled in their structural complexity, chemical diversity, and biological specificity, which has long made them crucial to the drug discovery process. South Africa is rich in both plant and marine biodiversity and a great deal of research has gone into isolating compounds from organisms found in this country. However, there is no official database containing this information, making it difficult to access for research purposes. This information was extracted manually from literature to create a database of South African natural products. In order to make the information accessible to the general research community, a website, named “SANCDB”, was built to enable compounds to be quickly and easily searched for and downloaded in a number of different chemical formats. The content of the database was assessed and compared to other established natural product databases. Currently, SANCDB is the only database of natural products in Africa with an online interface. The second section of the thesis was aimed at performing structural characterisation of proteins with the potential to be targeted for antimalarial drug therapy. This looked specifically at 1) The interactions between an exported heat shock protein (Hsp) from Plasmodium falciparum (P. falciparum), PfHsp70-x and various host and exported parasite J proteins, as well as 2) The interface between PfHsp90 and the heat shock organising protein (PfHop). The PfHsp70-x:J protein study provided additional insight into how these two proteins potentially interact. Analysis of the PfHsp90:PfHop also provided a structural insight into the interaction interface between these two proteins and identified residues that could be targeted due to their contribution to the stability of the Hsp90:Hop binding complex and differences between parasite and human proteins. These studies inspired the development of a homology modelling tool, which can be used to assist researchers with homology modelling, while providing them with step-by-step control over the entire process. This thesis presents the establishment of a South African NP database and the development of a homology modelling tool, inspired by protein structural studies. When combined, these two applications have the potential to contribute greatly towards in silico drug discovery research.
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Date Issued: 2016

Structure based docking and molecular dynamic studies of plasmodial cysteine proteases against a South African natural compound and its analogs:

- Musyoka, Thommas M, Kanzi, Aquillah M, Lobb, Kevin A, Tastan Bishop, Özlem

Authors: Musyoka, Thommas M , Kanzi, Aquillah M , Lobb, Kevin A , Tastan Bishop, Özlem
Date: 2016
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/148027 , vital:38703 , DOI: 10.1038/srep23690
Description: Identification of potential drug targets as well as development of novel antimalarial chemotherapies with unique mode of actions due to drug resistance by Plasmodium parasites are inevitable. Falcipains (falcipain-2 and falcipain-3) of Plasmodium falciparum, which catalyse the haemoglobin degradation process, are validated drug targets. Previous attempts to develop peptide based drugs against these enzymes have been futile due to the poor pharmacological profiles and susceptibility to degradation by host enzymes. This study aimed to identify potential non-peptide inhibitors against falcipains and their homologs from other Plasmodium species.
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Date Issued: 2016

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Students’ reception of peer assessment of group-work contributions: problematics in terms of race and gender emerging from a South African case study

- Thondhlana, Gladman, Belluigi, Dina Z

Authors: Thondhlana, Gladman , Belluigi, Dina Z
Date: 2016
Language: English
Type: article , text
Identifier: http://hdl.handle.net/10962/59784 , vital:27649 , https://doi.org/10.1080/02602938.2016.1235133
Description: Participatory assessment is increasingly employed in higher education worldwide as a formative mechanism to support students’ active learning. But do students in an increasingly relationally diverse environment perceive that peer assessment of individuals’ contributions to group-work tasks enhances their learning? Recognising the impact of students’ conceptions on the quality of their learning, this study considers students’ perspectives of peer assessment of group-work contributions at a South African university. Questionnaires elicited students’ perspectives of and general attitudes towards assessment of and by their peers. A growing measure of discontent with the process of assessing peer contributions to group tasks emerged, including actual and perceived racial and gender stereotyping, and related rejection-sensitivity. These initial findings were checked against the students’ experiences in a report-and-respond process that enabled probing discussions of the interpretations. This paper examines and explores the implications of such identifications and receptions for learning engagement and group-work curriculum development in the context of a rapidly transforming higher education sector.
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Date Issued: 2016

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Studies on comparison of aluminium-pillared montmorillonite clay with silica gel on adsorption of methylene blue in waste water

- Mselana, Sinazo

Authors: Mselana, Sinazo
Date: 2016
Subjects: Clay Silica gel Montmorillonite
Language: English
Type: Thesis , Masters , MSc
Identifier: http://hdl.handle.net/10353/8011 , vital:31462
Description: Adsorption equilibrium and kinetics of methylene blue (MB) onto silica gel and aluminum pillared montmorillonite was studied in a batch system. Variables of the system include contact time, salt concentration and initial methylene blue concentration. Langmuir and Freundlich isotherm models were applied to experimental equilibrium data of methylene blue adsorption. Both models were suitable for the parameters. The advantage of silica gel as applied to water treatment is its high porosity when compared to aluminum pillared montmorillonite clay. Water molecules adhere to the silica gels surface because it exhibits a lower vapour pressure than the surrounding air. When equilibrium of equal pressure is reached, no more adsorption occurs. Thus the higher the humidity of the surrounding air, the greater the amount of water that is adsorbed before equilibrium is reached. The increase in pressure loss on the silica gel filters is 1.5 - 2.0 times smaller than in the case of sand filters, Lorenc (2007).
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Date Issued: 2016

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Study into the synthesis, characterisation and applications of Vanadium-based metal organic frameworks, using 1, 2, 4, 5-benzenetetracarboxylic acid

- Feldmann, Wesley

Authors: Feldmann, Wesley
Date: 2016
Language: English
Type: text , Thesis , Masters , MSc
Identifier: http://hdl.handle.net/10962/55245 , vital:26680
Description: This study focussed on the synthesis, characterisation and catalytic application of synthesised vanadium-based Metal-Organic Frameworks using 1,2,4,5-benzenetetracarboxylic acid as a ligand. A number of synthetic methods were tested in multiple attempts to synthesise a V-MOF, these included; ambient, gel, reflux and solvothermal methods of synthesis. Two products of interest were identified, an ambient synthesis produced a vanadium-based complex with the empirical formula: V2O2(Na2H2B4C).6H2O (RU-V2) and a solvothermal synthesis produced a MOF with the empirical formula: V2O2(H2O)2(B4C) (RU-V1). Both products were characterised using elemental analysis, infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry and X-ray powder diffraction. The catalytic activity of these products was tested, alongside the activity of the solid decavanadate ion, for the conversion of cyclohexene to cyclohexene oxide. The decavanadate ion was included to determine if the ion was catalytically active in the solid state, to potentially be used in the construction of a future MOF or V-complex. The reaction for the conversion of cyclohexene to cyclohexene oxide was chosen, as it has been previously conducted using a V-MOF and was found to be successful. The product of the reaction, the epoxide: cyclohexene oxide, is a very useful precursor for a number of reactions involved in the pharmaceutical industry, so developing catalysts which are able to convert cyclohexene to the epoxide with high yields and selectivities are well sought after in industry. The results of the catalytic reactions were varied, as the materials exhibited high yields and selectivities to the epoxide, but these results were only obtained when water was present in the reaction mixture. Water was able to bring about the cleavage of the bonds between the metal and ligand in a highly coordinated framework, at a faster rate than other solvents, such as decane. This ultimately leads to the structural decomposition of the entire complex or framework, depending upon the reaction time. The use of water was a double edged sword in that it was required to initiate the catalytic reaction, but was also the reason that the catalytic materials were noted to decompose over time. The solid decavanadate ion was only noted to exhibit homogeneous activity by dissolving into the small volume of water present in the reaction mixture. The study proved that using a multidentate ligand such as 1,2,4,5-benzenetetracarboxylic acid yielded products which were highly coordinated in nature and would therefore not have large open spaces associated with them, which is commonly observed with other MOFs. Instead the closed nature of the synthesised complexes and frameworks offered a different environment for catalytic reactions, where the small pores/channels had a controlling and inhibiting effect on the reaction. The conversion of cyclohexene to the epoxide is accompanied with a number of undesired side products, so when using the synthesised closed-natured MOF, it was found that there was a greater selectivity for the epoxide over other potential products. This indicates that close natured MOFs may find application in catalytic reactions which require high selectivities for a particular product.
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Date Issued: 2016

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Study South Africa

- International Education Association of South Africa (IEASA), Jooste, Nico

Authors: International Education Association of South Africa (IEASA) , Jooste, Nico
Date: 2016
Subjects: Education, Higher -- South Africa , Universities and colleges -- South Africa , Technical Institutes -- South Africa , Vocational guidance -- South Africa
Language: English
Type: text , book
Identifier: http://hdl.handle.net/10962/64838 , vital:28614 , ISBN 9780620733601
Description: [Editor's Letter]: Study South Africa over time provided an annual overview of the South African Higher Education landscape as well as a forecast of some of the issues that could influence higher education in general and higher education internationalization in particular in South Africa for the year ahead. The 2016/17 issue being the 16th edition of Study South Africa provides an overview of the sector and a short description of all South African Public Higher Education institutions. This year, the Study SA Guide provides information about the system as well as articles that begin to address critical issues influencing the sector. It is foreseen that this would become a general feature in editions to come. The article that introduces a fundamental change in operations of South African Universities, beginning in 2016 and continuing into 2016 is the issue of the student protests on high tuition fees in South Africa. The #FEESMUSFALL movement introduced a topic that is fundamental to the internationalization of South African Higher Education. This event that began as a reaction to the increase in student fees for the 2016 academic year mutated into a social movement on university campuses throughout South Africa that challenged the way Universities function. Although not a mass based movement, but rather a movement driven by a desire to change the current social order in South Africa by a radical fringe, its focus is to use the plight of insufficient funding within South African Higher Education and in particular, focusing on funding of the poor. For a large part the issues raised by students is not in the domain of Higher Education, but a competency of Government and broader society. The influence of the constant disruption of academic activities on all South African University campuses resulted in a tendency to be an inwardly focused system where most of the energy is spent on local issues. South African Higher Education is known for its international connectedness and the way the international world accepted it into their fold as a critical player in a variety of fields, bringing a different voice to global debates. The hosting of Going Global by the British Council in May 2016 in Cape Town and the hosting of the Global Conference in August 2016 by IEASA in the Kruger National Park clearly demonstrated that South African Higher Education is globally an important player. The current situation in South Africa should be seen by the outside world as a process of internal re-evaluation. It is also a struggle to bring together the global and the local. It is a process that is currently driven by South African Higher Education institutions. Although the issues that triggered the revolt is local, the roots are global and our solution to the problem could become a guide to global higher education. It is thus necessary that all the partners of the South African system believe in South Africa as the carrier of goodwill and a message that is worth listening to. It is also necessary to rather engage with South African Universities to understand the issues and not to abandon them at this critical stage. This issue of Study South Africa should remain the connector with the global higher education system and the information provided will hopefully assist all those interested in keeping and building on this connection. , 16th Edition
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Date Issued: 2016

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Subcellular localisation of Theiler's murine encephalomyelitis virus (TMEV) capsid subunit VP1 vis-á-vis host protein Hsp90:

- Ross, Caroline J, Upfold, Nicole, Luke, Garry A, Tastan Bishop, Özlem, Knox, Caroline M

Authors: Ross, Caroline J , Upfold, Nicole , Luke, Garry A , Tastan Bishop, Özlem , Knox, Caroline M
Date: 2016
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/148016 , vital:38702 , DOI: 10.1016/j.virusres.2016.06.003
Description: The VP1 subunit of the picornavirus capsid is the major antigenic determinant and mediates host cell attachment and virus entry. To investigate the localisation of Theiler's murine encephalomyelitis virus (TMEV) VP1 during infection, a bioinformatics approach was used to predict a surface-exposed, linear epitope region of the protein for subsequent expression and purification. This region, comprising the N-terminal 112 amino acids of the protein, was then used for rabbit immunisation, and the resultant polyclonal antibodies were able to recognise full length VP1 in infected cell lysates by Western blot. Following optimisation, the antibodies were used to investigate the localisation of VP1 in relation to Hsp90 in infected cells by indirect immunofluorescence and confocal microscopy.
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Date Issued: 2016

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Successes and challenges of women's income generating projects in Zimbabwe

- Hamunakwadi, Purity

Authors: Hamunakwadi, Purity
Date: 2016
Subjects: Women in development -- Zimbabwe , Women -- Employment -- Zimbabwe , Economic development projects -- Zimbabwe , Women in rural development -- Zimbabwe
Language: English
Type: Thesis , Masters , MA
Identifier: http://hdl.handle.net/10948/6810 , vital:21145
Description: Women’s income-generating projects are regarded as a critical area in promoting sustainable livelihoods in the lives of the poor. This study centres on a cattle project in Sadomba village in Nyanga District, Zimbabwe. The purpose of this study is to investigate the role and contributions of income-generating projects with regard to women; the necessary conditions for a successful cattle production project; the major challenges in women’s income-generating projects, and how income-generating projects can be strengthened, all in relation to this cattle project.The study is underpinned by the sustainable livelihood approach and literature on micro-financing of women’s projects in various countries. The study is based on qualitative methodology using a case study design and methods of data collection included semi-structured interviews, focus group discussions and participant observation. The data was analysed using thematic analysis and sub-themes that arose in the study and thereafter all the data was grouped by a process of coding. The results indicated that the Sadomba cattle project has benefited the project members in terms of income generation by the selling of cattle and milk, for agricultural purposes (draught power) and also income they obtained from hiring their cattle to other community members in rainy seasons. The income generated has assisted them to send their children to school and attain higher education.In addition, it promotes community engagement when they share paddocks and dip tanks. However, despite these benefits, they face a number of challenges such as long distances to the market, a lack of microcredit and the unavailability of exotic breeds. Therefore, there is need to integrate the conditions that are necessary for successful income generating projects to the Sadomba cattle project.
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Date Issued: 2016

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Supplementary Material Synthesis and biological evaluation of (E)-cinnamic acid,(E)-2-styrylthiazole and (E)-2-[2-(naphthalen-1-yl) vinyl] thiazole derivatives

- Olawode, Emmanuel O, Tandlich, Roman, Prinsloo, Earl, Isaacs, Michelle, Hoppe, Heinrich C, Seldon, Ronnett, Warner, Digby F, Steenkamp, Vanessa, Kaye, Perry T

Authors: Olawode, Emmanuel O , Tandlich, Roman , Prinsloo, Earl , Isaacs, Michelle , Hoppe, Heinrich C , Seldon, Ronnett , Warner, Digby F , Steenkamp, Vanessa , Kaye, Perry T
Date: 2016
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/431778 , vital:72803 , xlink:href=" https://www.arkat-usa.org/get-file/59868/"
Description: The screening was conducted using multi-well plates which are suited for HeLa cells in the log phase of growth with final cell density > 10 cells/cm. Each experiment normally includes a blank control, containing medium without the cells.28,45 Non-contaminated HeLa cells (6.57 x 105 cells per well) in media were allowed to grow in the incubator under an atmosphere of 5% CO2 at 37 0C for 24 h. To each well was dispensed 200 µL of HeLa culture, containing 6.57 x 105 cells under LabEAir laminar flow hood (Vivid Air, South Africa); 20 µL of resazurin dye (Sigma TOX-8) and test compound (50 µL) were added, which were then incubated in the presence of 5% CO2 at 37 0C for 24 hours in a shaker, to enhance the distribution of the dye. The absorbance of each well was measured with Bio-tek Power Wave X fluorometer (Beijing, China), and increases in fluorescence was monitored at a wavelength of 590 nm, using an excitation wavelength of 560 nm.
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Date Issued: 2016

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Supra-maximal speed interval training effect on a 40m standing start sprint and timed 3000m running performance in moderately trained female runners: Alterg anti-gravity treadmill running

- Ellerbeck, Tim

Authors: Ellerbeck, Tim
Date: 2016
Subjects: Interval training , Women runners , Running -- Training
Language: English
Type: Thesis , Masters , MA
Identifier: http://hdl.handle.net/10948/6772 , vital:21140
Description: The purpose of this study was to explore what the supra-maximal speed interval training effect was on a 40m standing start sprint and timed 3000m running performance was for two separate study groups when using either the AlterG® anti-gravity treadmill, or downhill running as a training intervention, for moderately trained female runners. The level of delayed onset of muscle soreness (DOMS) after each supra-maximal speed interval session was also captured. Data from 20 women was collected during initial pre-intervention testing; involving the 40m standing start sprint and 3000m timed trial run. During a four week training intervention the level of DOMS experienced by participants at increments of 24 hours, 48 hours and 72 hours, in each respective training group was recorded. Post-intervention testing was performed to once again measure the participants 40m standing start sprint and 3000m timed trial run values, results were analysed and compared to pre-intervention data.
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Date Issued: 2016

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Surface characteristics of rock glaciers in the Jutulsessen, Dronning Maud Land, Antarctica

- Rudolph, Elizabeth Magdalena

Authors: Rudolph, Elizabeth Magdalena
Date: 2016
Language: English
Type: Thesis , Masters , MSc
Identifier: http://hdl.handle.net/10962/2667 , vital:20314
Description: Rock glaciers are landforms that present downslope movement of debris under the influence of ice and gravity. These landforms can be used as paleo-climate indicators as well as proxies for climate change. Rock glaciers have been investigated in a variety of climates and landscapes, however continental Antarctica, Dronning Maud Land specifically, remains understudied. This thesis aimed to investigate and classify five rock glaciers observed in the Jutulsessen, Dronning Maud Land. The surface characteristics and geomorphology were assessed and used as generic classifiers. Size, shape and landscape association was established by field surveying and GIS, whilst sediment and clast characteristics were determined from sampling. A surface temperature profile was created from short-term high frequency temperature measurements. All of the rock glaciers exhibit either undulating surfaces or patterned ground, or both, which suggests active-layer related processes. Sediment particle size analysis is inconclusive. The 137Cs-content and fabric analysis suggest movement regimes similar to other rock glaciers with higher activity at the head, and variable movement directions at the toe. Relative “activeness” is inferred from morphology: Grjotlia, Grjotøyra and Vassdalen were classified as lobate, spatulate and tongue-shaped respectively with Grjotlia the most stable. A new morphological classification of ‘crown-shaped’ is suggested for Brugdedalen and Jutuldalen, and they also appear most active. The control of local climate on rock glacier mechanics is emphasised by the findings, and thus climatic interpolation from a single weather stations is not useful. Increased spatial and temporal coverage of sediment profiles, surface topography and active-layer characteristics could be used to elucidate the processes and controls of these landforms in the Antarctic.
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Date Issued: 2016

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Surfing the waves of learning: enacting a Semantics analysis of teaching in a first-year Law course

- Clarence, Sherran

Authors: Clarence, Sherran
Date: 2016
Language: English
Type: article , text
Identifier: http://hdl.handle.net/10962/59816 , vital:27654 , https://doi.org/10.1080/07294360.2016.1263831
Description: Students’ ability to build knowledge, and transfer it within and between contexts is crucial to cumulative learning and to academic success. This has long been a concern of higher education research and practice. A central part of this concern for educators is creating the conditions that enable their students' deep learning, as this is an area of significant struggle for many students. Legitimation Code Theory, in particular the dimension of Semantics, is proving useful in examining the kinds of conditions that may be necessary for students to build disciplinary knowledge cumulatively over time. Using illustrative data from one case study, this paper suggests that the conceptual tools offered by Semantics can provide academic lecturers and academic development staff with a set of conceptual and analytical tools which can enable them to ‘see’ and understand the ways in which knowledge can be cumulatively acquired and used, as well as the possible gaps between what they are teaching and what their students may be learning. The hope is that these new insights will provide new directions for change in teaching and learning where these may be needed.
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Date Issued: 2016

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Sustainble public bus transport services in the Nelson Mandela Bay

- Mntwini, Mkhonto

Authors: Mntwini, Mkhonto
Date: 2016
Subjects: Urban transportation -- Economic aspects Urban transportation -- Research Transportation -- Customer services
Language: English
Type: Thesis , Masters , MBA
Identifier: http://hdl.handle.net/10948/11875 , vital:27000
Description: Purpose - Transport is a common constant variable found in just about every aspect of our lives as well as commercial activities; this is so because transport enables accessibility to people, places and goods. The effective management of public passenger transport operations is a more complex and all-embracing concept than what it may appear at first glance. Wider dispersed work place locations and urban sprawl is on the rise driven by among other factors the increased rate of globalisation. A unique opportunity is then presented in a developing country like South Africa for effective planning and management of public passenger bus operations. In the main, the purpose of this case study research was to develop a more sustainable public passenger transport bus operation to better connect people, places and goods. The organisation that will be studied is Blunden Coach Tours a luxury and semi-lux coach Tour operator, operating from the Nelson Mandela Bay. Design / Methodology / Approach – This study employed the case study research approach which was based on the qualitative research paradigm as such allowed for in-depth description and analysis of the case as well as related phenomena in real world context. The researcher focused only on the public passenger bus transport operations in Nelson Mandela Bay thus assuming a single context focus with a single case namely the development of a more sustainable public passenger transport operations in Nelson Mandela Bay. An embedded multiple unit of analysis strategy was employed selecting a sample of key persons responsible for strategic operational areas at Blunden Coach tours, sub-contractors and suppliers. The case study employed an in-depth probing interview process in an effort to better comprehend occurrences within the actual context of the events observed. The secondary sources of information gathered were used to structure and backup the interview questions. Practical implications – The case study enabled thought provoking insight which by virtue of South Africa’s historical socio-economic landscape offered an unusual perspective of the South African bus transport scene with a particular focus on environmental, regulatory and socio-economic sustainability considerations. A limitation to the study – The lack of responses to the interview questions from some of the key role players in the bus industry who were contacted as well as some of the respondents interviewed. The lack of responses to some of the interview questions could be perceived as a limitation to validating the Summary drawn from the study.
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Date Issued: 2016

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Synthesis and characterisation of lanthanide complexes with nitrogen- and oxygen-donor ligands

- Madanhire, Tatenda

Authors: Madanhire, Tatenda
Date: 2016
Subjects: Rare earth metals
Language: English
Type: Thesis , Masters , MSc
Identifier: http://hdl.handle.net/10948/13127 , vital:27154
Description: The reactions of Ln(NO3)3∙6H2O (Ln = Pr, Nd or Er) with the potentially tridentate O,N,O chelating ligand 2,6-pyridinedimethanol (H2pydm) were investigated, and complexes with the formula, [Ln(H2pydm)2(NO3)2](NO3) (Ln = Pr or Nd) and [Er(H2pydm)3](NO3)3 were isolated. The ten-coordinate Pr(III) and Nd(III) compounds crystallise in the triclinic space group P-1 while the nine-coordinate Er(III) complex crystallises in the monoclinic system (P21/n). The reaction of PrCl3∙6H2O with H2pydm yielded the compound, [Pr(H2pydm)3](Cl)3, that crystallises in the monoclinic system, space group P21/c with α = 90, β = 98.680(1) and γ = 90°. The nine-coordinate Pr(III) ion is bound to three H2pydm ligands, with bond distances Pr-O 2.455(2)-2.478(2) Å and Pr-N 2.6355(19)-2.64(2) Å. X-ray crystal structures of all the H2pydm complexes reveal that the ligand coordinates tridentately, via the pyridyl nitrogen atom and the two hydroxyl oxygen atoms. The electronic absorption spectra of complexes show 4f-4f transitions. Rare-earth complexes, [Ln(H2L1)2(NO3)3] [Ln = Gd, Ho or Nd], were also prepared from a Schiff base. The X-ray single-crystal diffraction studies and SHAPE analyses of the Gd(III) and Ho(III) complexes shows that the complexes are ten-coordinate and exhibit distorted tetradecahedron geometries. With proton migration occurring from the phenol group to the imine function, complexation of the lanthanides to the ligand gives the ligand a zwitterionic phenoxo-iminium form. A phenolate oxygen-bridged dinuclear complex, [Ce2(H2L1)(ovan)3(NO3)3], has been obtained by reacting Ce(NO3)3∙6H2O with an o-vanillin derived Schiff base ligand, 2-((E)-(1-hydroxy-2-methylpropan-2-ylimino)methyl)-6-methoxyphenol (H2L1). Hydrolysis of the Schiff base occurred to yield o-vanillin, which bridged two cerium atoms with the Ce∙∙∙Ce distance equal to 3.823 Å. The Ce(III) ions are both tencoordinate, but have different coordination environments, showing tetradecahedron and staggered dodecahedron geometries, respectively. The reaction of salicylaldehyde-N(4)-diethylthiosemicarbazone (H2L2) in the presence of hydrated Ln(III) nitrates led to the isolation of two novel compounds: (E)-2[(ortho-hydroxy)benzylidene]-2-(thiomethyl)-thionohydrazide (1) and bis[2,3-diaza4-(2-hydroxyphenyl)-1-thiomethyl-buta-1,3-diene]disulfide. The latter is a dimer of the former. For this asymmetric Schiff base, 1 and the symmetric disulfide, classical hydrogen bonds of the O–H∙∙∙N as well as N–H∙∙∙S (for 1) type are apparent next to C–H∙∙∙O contacts. 4-(4-Bromophenyl)-1-(propan-2-ylidene)thiosemicarbazide was also prepared upon reacting 4-(4-bromophenyl)-3-thiosemicarbazide with acetone in the presence of ethanol and La(NO3)3∙6H2O. The C=S bond length was found to be 1.6686(16) Å which is in good agreement with other thioketones whose metrical parameters have been deposited with the Cambridge Structural Database. Classical hydrogen bonds of the N–H∙∙∙N and the N–H∙∙∙Br type are observed next to C–H∙∙∙S contacts. All synthesised compounds were characterised by microanalyses, single-crystal X-ray diffraction (except for [Nd(H2L1)2(NO3)3]), 1H NMR and IR spectroscopy.
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Date Issued: 2016

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Synthesis and characterization of group 12 dithiolate complexes as single source precursors for the preparation of hexadecylamine capped metal sulfide nanoparticles and polymer

- Osuntokun, Jejenija

Authors: Osuntokun, Jejenija
Date: 2016
Subjects: Nanotechnology Nanoparticles Semiconductors
Language: English
Type: Thesis , Doctoral , PhD
Identifier: http://hdl.handle.net/10353/14060 , vital:39801
Description: A series of heteroleptic mixed ligand complexes of some alkyl substituted thiourea, tetramethyl thiuram disulfide and 1-cyano-1-carboethoxy-2,2 ditholate of Zn(II) Cd(II) and Hg(II) have been synthesized by stoichiometry reactions of the ligands with respective metal salts. They have been characterized with analytical and spectroscopic techniques. Seven out of the 19 complexes synthesized are pyridine 2, 2 bipyridine and 1, 10 phenanthroline adducts of dissopropyl parent adducts of Zn(II) and Cd(II) complexes. All the complexes are proposed as four coordinate except the pyridine adducts, 2, 2’ bipyridine and 1, 10 phenanhroline adducts that are proposed as five and six coordinate respectively. All the complexes are solid, air stable and moisture stable for a many months. They are not soluble in common organic solvents but partially soluble in coordinating solvents like DMF and DMSO and due to their insolubility problems all attempts to grow single crystal of the complexes proved abortive. The complexes gave respective metal sulfide on thermal decomposition in TGA and this makes them to be potentially useful single source precursor for the synthesis of metal sulfide. All the complexes were invariably thermolysed in HDA to synthesis a series of HDA-capped ZnS, CdS and HgS nanoparticles. The optical properties of the nanoparticles reveal that they are all blue-shifted from the absorbance edge and this confirms quantum confinement of the nanoparticles. The transmittance electron microscope showed that the nanoparticles are in nanodimension. ZnS nanoparticles from the pyridine adducts gave HDA-capped ZnS nanoparticles with a mixture of hexagonal and cubic phases while the HDA capped CdS from the 2, 2 bipyridine and 1,10 phenanthroline gave anisotropic nanoparticles. The sizes of the CdS from the 1,10 phenanthroline adducts were also found to be biggest while CdS nanoparticles from 2,2 bipyridine adduct were also revealed to be bigger than the particle sizes obtained from the parent complex, (1-cyano-1 carboethoxyethylene-2,2-dithiolato- κ,S’S)-bis(N, N’-diisopropylthiourea -κS)cadmium(II). ZnS and CdS polymer encapsulated nanocomposites were also synthesized using a solution casting method. The polymers employed were; Polymethyl metharcrylate (PMMA), Poly(vinly alcohol) (PVA), and poly vinyl pyrrolidone (PVP). The structural and thermal properties of the pure polymers and the respective nanocomposites were investigated. It was observed that the ZnS/PVA and CdS/PVA were the most thermally stable composites when the thermal stability of the pure polymers were compared relative to the nanocomposites using data obtained from thermal decomposition results of the TGA.
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Date Issued: 2016

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Synthesis and dark toxicity of 5-(4-carboxyphenyl)-10, 15, 20-tris (phenyl)-porphyrinato chlorido gallium (III) when conjugated to δ-aminolevulinic acid

- Managa, Muthumuni, Mkhize, Scebi, Britton, Jonathan, Prinsloo, Earl, Nyokong, Tebello

Authors: Managa, Muthumuni , Mkhize, Scebi , Britton, Jonathan , Prinsloo, Earl , Nyokong, Tebello
Date: 2016
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/240014 , vital:50789 , xlink:href="https://doi.org/10.1080/00958972.2016.1223292"
Description: 5-(4-Carboxyphenyl)-10,15,20-tris(phenyl)-porphyrinato chlorido gallium(III) (2) was synthesized and then linked to ethyl ester δ-aminolevulinic acid to form 3. There was no shift in Soret band following conjugation. The fluorescence and singlet oxygen generating behavior of the porphyrins were also investigated. The highest singlet oxygen quantum yield (ΦΔ) obtained was that of 3. Complexes 2 and 3 as well as metal free 5-(4-carboxyphenyl)-10,15,20-tris(phenyl)-porphyrinato showed no dark toxicity on MCF-7 breast cancer cells.
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Date Issued: 2016

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Synthesis and evaluation of substituted 4-(N-benzylamino)cinnamate esters as potential anti-cancer agents and HIV-1 integrase inhibitors

- Faridoon, H, Edkins, Adrienne L, Isaacs, Michelle, Mnkandhla, Dumisani, Hoppe, Heinrich C, Kaye, Perry T

Authors: Faridoon, H , Edkins, Adrienne L , Isaacs, Michelle , Mnkandhla, Dumisani , Hoppe, Heinrich C , Kaye, Perry T
Date: 2016
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/66289 , vital:28929 , https://doi.org/10.1016/j.bmcl.2016.05.023
Description: publisher version , Encouraging selectivity and low micromolar activity against HeLa cervical carcinoma (IC50 ⩾ 3.0 μM) and the aggressive MDA-MB-231 triple negative breast carcinoma (IC50 ⩾ 9.6 μM) cell lines has been exhibited by a number of readily accessible 4-(N-benzylamino)cinnamate esters. The potential of the ligands as HIV-1 integrase inhibitors has also been examined.
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Date Issued: 2016

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