Synthesis, photophysical and nonlinear optical properties of a series of ball-type phthalocyanines in solution and thin films
- Nwaji, Njemuwa, Mack, John, Britton, Jonathan, Nyokong, Tebello
- Authors: Nwaji, Njemuwa , Mack, John , Britton, Jonathan , Nyokong, Tebello
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188976 , vital:44803 , xlink:href="https://doi.org/10.1039/C6NJ03662G"
- Description: In this study, we report on the enhanced nonlinear optical properties of novel tetrakis-4-(hexadecane-1,2-dioxyl)-bis(phthalocyaninato zinc(II)) (4), tetrakis-4-(hexadecane-1,2-dioxyl)-bis(phthalocyaninato gallium chloride) (5) and tetrakis-4-(hexadecane-1,2-dioxyl)-bis(phthalocyaninato indium chloride) (6) both in solution and when embedded in polymer thin films. Complexes 5 and 6 bearing heavy atoms showed enhanced triplet quantum yield and nonlinear optical response. The nonlinear third-order susceptibility and second-order hyperpolarizability values are also reported. Time dependent density functional theory (TD-DFT) calculations were performed in order to explain the origin of the observed UV-vis and magnetic circular dichroism (MCD) spectra of the complexes.
- Full Text:
- Date Issued: 2017
- Authors: Nwaji, Njemuwa , Mack, John , Britton, Jonathan , Nyokong, Tebello
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188976 , vital:44803 , xlink:href="https://doi.org/10.1039/C6NJ03662G"
- Description: In this study, we report on the enhanced nonlinear optical properties of novel tetrakis-4-(hexadecane-1,2-dioxyl)-bis(phthalocyaninato zinc(II)) (4), tetrakis-4-(hexadecane-1,2-dioxyl)-bis(phthalocyaninato gallium chloride) (5) and tetrakis-4-(hexadecane-1,2-dioxyl)-bis(phthalocyaninato indium chloride) (6) both in solution and when embedded in polymer thin films. Complexes 5 and 6 bearing heavy atoms showed enhanced triplet quantum yield and nonlinear optical response. The nonlinear third-order susceptibility and second-order hyperpolarizability values are also reported. Time dependent density functional theory (TD-DFT) calculations were performed in order to explain the origin of the observed UV-vis and magnetic circular dichroism (MCD) spectra of the complexes.
- Full Text:
- Date Issued: 2017
Tetra 4-(propargyloxy)phenoxy phthalocyanines: synthesis, spectroscopic, nonlinear optical and electrocatalytic properties
- Authors: Mwanza, Daniel
- Date: 2017
- Subjects: Phthalocyanines , Nonlinear optics , Electrocatalysis , Spectrum analysis , Thermogravimetry , Phthalocyanines Spectra
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/65144 , vital:28695
- Description: This study presents the synthesis, spectroscopic, photophysical and theoretical characterisation of metal-free (H2TPrOPhOPc), cobalt (CoTPrOPhOPc) and manganese (MnTPrOPhOPc) tetra 4-(4-propargyloxy) phenoxy phthalocyanines. Thermal analysis using thermogravimetric analysis (TGA) confirmed the excellent thermal stability of synthesized tetra 4-(4- propargyloxy) phenoxy phthalocyanines. The metal complexes, CoTPrOPhOPc and MnTPrOPhOPc, exhibited better thermal stability when compared to H2TPrOPhOPc. The residual percentage weight remaining was approximately 70% for CoTPrOPhOPc and MnTPrOPhOPc and 45% for H2TPrOPhOPc after 600°C, clearly confirming the stability of the metal complexes. The MTPrOPhOPcs (where M = H2, Co and Mn) complexes exhibited excellent nonlinear optical properties with strong reverse saturable absorption (RSA), especially when 560 nm excitation laser was used. Their nonlinear optical properties followed this trend: H2TPrOPhOPc > CoTPrOPhOPc > MnTPrOPhOPc. According to the trend observed, the H2TPrOPhOPc was an excellent nonlinear optical limiter when compared to the CoTPrOPhOPc and MnTPrOPhOPc. All the investigated complexes exhibited optical limiting properties comparable to the phthalocyanine complexes reported in the literature. The MTPrOPhOPc complexes were further studied for their electrocatalytic and electroanalytical properties towards the detection of hydrogen peroxide. For the electrocatalytic studies, the synthesized complexes were immobilized onto gold electrode surfaces pre-functionalized with phenylazide (Au-PAz) monolayer. Copper (I) catalyzed alkynyl-azide cycloaddition reaction was used to covalently immobilize the MTPrOPhOPcs onto the gold electrode surfaces to form Au-PAz-MTPrOPhOPc. The MTPrOPhOPcs modified gold surfaces (Au-PAz-MTPrOPhOPc) exhibited good reproducibility and stability in various electrolyte conditions. Electrochemical and surface characterisation of the functionalised gold electrode surfaces confirmed the presence of the MTPrOPhOPcs and their electroanalysis was excellent towards electrocatalytic reduction of H2O2, with the limit of detection (LoD) and limit of quantification (LoQ) in the ^M range. The electrocatalytic reduction peaks for H2O2 were observed at -0.37 V for Au-PAz-MnTPrOPhOPc and -0.31 V for Au-PAz-CoTPrOPhOPc when Ag|AgCl pseudo-reference electrode was used. The Au-PAz-MnTPrOPhOPc and Au- PAz-CoTPrOPhOPc gold electrode surfaces showed good sensitivity and reproducibility towards the electrocatalytic reduction of hydrogen peroxide in pH 7.4 phosphate buffer solution. , Thesis (MSc) -- Faculty of Science, Chemistry, 2017
- Full Text:
- Date Issued: 2017
- Authors: Mwanza, Daniel
- Date: 2017
- Subjects: Phthalocyanines , Nonlinear optics , Electrocatalysis , Spectrum analysis , Thermogravimetry , Phthalocyanines Spectra
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/65144 , vital:28695
- Description: This study presents the synthesis, spectroscopic, photophysical and theoretical characterisation of metal-free (H2TPrOPhOPc), cobalt (CoTPrOPhOPc) and manganese (MnTPrOPhOPc) tetra 4-(4-propargyloxy) phenoxy phthalocyanines. Thermal analysis using thermogravimetric analysis (TGA) confirmed the excellent thermal stability of synthesized tetra 4-(4- propargyloxy) phenoxy phthalocyanines. The metal complexes, CoTPrOPhOPc and MnTPrOPhOPc, exhibited better thermal stability when compared to H2TPrOPhOPc. The residual percentage weight remaining was approximately 70% for CoTPrOPhOPc and MnTPrOPhOPc and 45% for H2TPrOPhOPc after 600°C, clearly confirming the stability of the metal complexes. The MTPrOPhOPcs (where M = H2, Co and Mn) complexes exhibited excellent nonlinear optical properties with strong reverse saturable absorption (RSA), especially when 560 nm excitation laser was used. Their nonlinear optical properties followed this trend: H2TPrOPhOPc > CoTPrOPhOPc > MnTPrOPhOPc. According to the trend observed, the H2TPrOPhOPc was an excellent nonlinear optical limiter when compared to the CoTPrOPhOPc and MnTPrOPhOPc. All the investigated complexes exhibited optical limiting properties comparable to the phthalocyanine complexes reported in the literature. The MTPrOPhOPc complexes were further studied for their electrocatalytic and electroanalytical properties towards the detection of hydrogen peroxide. For the electrocatalytic studies, the synthesized complexes were immobilized onto gold electrode surfaces pre-functionalized with phenylazide (Au-PAz) monolayer. Copper (I) catalyzed alkynyl-azide cycloaddition reaction was used to covalently immobilize the MTPrOPhOPcs onto the gold electrode surfaces to form Au-PAz-MTPrOPhOPc. The MTPrOPhOPcs modified gold surfaces (Au-PAz-MTPrOPhOPc) exhibited good reproducibility and stability in various electrolyte conditions. Electrochemical and surface characterisation of the functionalised gold electrode surfaces confirmed the presence of the MTPrOPhOPcs and their electroanalysis was excellent towards electrocatalytic reduction of H2O2, with the limit of detection (LoD) and limit of quantification (LoQ) in the ^M range. The electrocatalytic reduction peaks for H2O2 were observed at -0.37 V for Au-PAz-MnTPrOPhOPc and -0.31 V for Au-PAz-CoTPrOPhOPc when Ag|AgCl pseudo-reference electrode was used. The Au-PAz-MnTPrOPhOPc and Au- PAz-CoTPrOPhOPc gold electrode surfaces showed good sensitivity and reproducibility towards the electrocatalytic reduction of hydrogen peroxide in pH 7.4 phosphate buffer solution. , Thesis (MSc) -- Faculty of Science, Chemistry, 2017
- Full Text:
- Date Issued: 2017
The applicability of anaerobically digested pasteurized pit latrine faecal sludge as a fertilizer to grow radish and garden cress
- Authors: Madikizela, Phindile
- Date: 2017
- Subjects: Sewage sludge as fertilizer , Sewage sludge digestion , Sewage Purification Anaerobic treatment
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/59235 , vital:27487
- Description: Pit latrine faecal sludge was recovered from numerous pit latrines in Hlalani Township, Grahamstown, South Africa. This material was used to prepare a fertilizer to demonstrate the value that could be captured from faecal sludge. Further anaerobic digestion, together with a co-feed demonstrated the potential of faecal sludge to produce low cost fertilizer that could be used to grow food crops. Biogas recovered from the anaerobic digester could be used to pasteurize its effluent, although effective biogas recovery and storage needs to be further addressed. Investigating the microbial community of the different depths of the pit latrine through molecular techniques showed that the fermenting bacteria family Clostridiaceae was the most commonly identified family throughout the different depths of the pit latrine, and that the microbial community within pit latrines was very diverse with bacterial families that are involved in nitrogen fixation, denitrification, and iron and sulphate reduction. Additionally, most of the bacterial families that dominated the seven studied pit latrines had members that were known human pathogens (Mycobacteriaceae, Dermatophilaceae Peptostreptococcaceae, Micrococcaceae, Staphylococcaceae, Leptospiraceae, Listeriaceae, Bradyrhizobiaceae and Brucellaceae). Effluent from a wastewater treatment works was selected as a co-feed to augment biogas production. The most successful faecal sludge and co-feed combination was shown to be the one made up of 33% and 66% pit latrine faecal sludge. 180 L of this effluent mixture generated 285 L of biogas over 45 days of anaerobic digestion (29±2°C). However, the recovered quantities were insufficient for pasteurization as 650 L of biogas was required to pasteurize 300 g of faecal sludge for 1 hour at 70±2°C. Therefore, liquid petroleum gas (LPG) was used as an alternative heating energy source. Anaerobic digestion and pasteurization rendered the faecal sludge safe for application as a fertilizer as the quality of the faecal sludge after treatment by anaerobic digestion and pasteurization was within the microbiological (Escherichia coli, Salmonella spp, Enterococcus faecium and helminth eggs) and trace element restrictions (Pb, Ni, Cr, Mo, As, Cu, Mn, Fe, Cd and Hg) of sludge application in agriculture as stipulated by the WHO and the South African Guidelines for Sludge Use in Agriculture. Radish (Raphanus sativus spp) and garden cress (Lepidium sativum) were cultivated to demonstrate the effectiveness of the anaerobically digested and pasteurized pit latrine faecal sludge as a fertilizer. Diluting the fertilizer prepared from faecal sludge did not reduce its efficacy and was comparable to the synthetic fertilizer used as a control in the growth trials in terms of the plant fresh weight, dry weight and plant height. Finally, the exposure to the current state of pit latrines in Hlalani Township provided an incentive to develop a new tool to address sanitation service delivery skill shortage (artisans, plant operation and maintenance workers, and sanitation and hygiene facilitators) through the use of volunteers. , Thesis (MSc) -- Faculty of Pharmacy, Pharmacy, 2017
- Full Text:
- Date Issued: 2017
- Authors: Madikizela, Phindile
- Date: 2017
- Subjects: Sewage sludge as fertilizer , Sewage sludge digestion , Sewage Purification Anaerobic treatment
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/59235 , vital:27487
- Description: Pit latrine faecal sludge was recovered from numerous pit latrines in Hlalani Township, Grahamstown, South Africa. This material was used to prepare a fertilizer to demonstrate the value that could be captured from faecal sludge. Further anaerobic digestion, together with a co-feed demonstrated the potential of faecal sludge to produce low cost fertilizer that could be used to grow food crops. Biogas recovered from the anaerobic digester could be used to pasteurize its effluent, although effective biogas recovery and storage needs to be further addressed. Investigating the microbial community of the different depths of the pit latrine through molecular techniques showed that the fermenting bacteria family Clostridiaceae was the most commonly identified family throughout the different depths of the pit latrine, and that the microbial community within pit latrines was very diverse with bacterial families that are involved in nitrogen fixation, denitrification, and iron and sulphate reduction. Additionally, most of the bacterial families that dominated the seven studied pit latrines had members that were known human pathogens (Mycobacteriaceae, Dermatophilaceae Peptostreptococcaceae, Micrococcaceae, Staphylococcaceae, Leptospiraceae, Listeriaceae, Bradyrhizobiaceae and Brucellaceae). Effluent from a wastewater treatment works was selected as a co-feed to augment biogas production. The most successful faecal sludge and co-feed combination was shown to be the one made up of 33% and 66% pit latrine faecal sludge. 180 L of this effluent mixture generated 285 L of biogas over 45 days of anaerobic digestion (29±2°C). However, the recovered quantities were insufficient for pasteurization as 650 L of biogas was required to pasteurize 300 g of faecal sludge for 1 hour at 70±2°C. Therefore, liquid petroleum gas (LPG) was used as an alternative heating energy source. Anaerobic digestion and pasteurization rendered the faecal sludge safe for application as a fertilizer as the quality of the faecal sludge after treatment by anaerobic digestion and pasteurization was within the microbiological (Escherichia coli, Salmonella spp, Enterococcus faecium and helminth eggs) and trace element restrictions (Pb, Ni, Cr, Mo, As, Cu, Mn, Fe, Cd and Hg) of sludge application in agriculture as stipulated by the WHO and the South African Guidelines for Sludge Use in Agriculture. Radish (Raphanus sativus spp) and garden cress (Lepidium sativum) were cultivated to demonstrate the effectiveness of the anaerobically digested and pasteurized pit latrine faecal sludge as a fertilizer. Diluting the fertilizer prepared from faecal sludge did not reduce its efficacy and was comparable to the synthetic fertilizer used as a control in the growth trials in terms of the plant fresh weight, dry weight and plant height. Finally, the exposure to the current state of pit latrines in Hlalani Township provided an incentive to develop a new tool to address sanitation service delivery skill shortage (artisans, plant operation and maintenance workers, and sanitation and hygiene facilitators) through the use of volunteers. , Thesis (MSc) -- Faculty of Pharmacy, Pharmacy, 2017
- Full Text:
- Date Issued: 2017
The contradictory conceptions of research in historically black universities
- Muthama, Evelyn, McKenna, Sioux
- Authors: Muthama, Evelyn , McKenna, Sioux
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187183 , vital:44577 , xlink:href="http://dx.doi. org/10.18820/2519593X/pie. v35i1.10"
- Description: Research is conceptualised in multiple and contradictory ways within and across Historically Black Universities (HBUs) with consequences for knowledge production. Under the apartheid regime, research was deliberately underdeveloped in such institutions and this continues to have an impact. We argue that if HBUs are to move from the constraints of the past into the possibilities of the future, there is a need for a thorough understanding both of how research is currently conceptualised, and of the consequences of such conceptions for research output. We used a critical discourse analysis of interviews, documents and survey data from seven HBUs to identify the dominant discourses about the purposes of research. The findings are four dominant conceptions of research that sometimes contradict each other across and within the HBUs. These are research as integral to academic identity; research for social justice; research as an economic driver and research as an instrumentalist requirement for job security, promotion and incentives. These conceptions seemed to emerge in part because of the history of the institutions and create both constraining and enabling effects on research production.
- Full Text:
- Date Issued: 2017
- Authors: Muthama, Evelyn , McKenna, Sioux
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187183 , vital:44577 , xlink:href="http://dx.doi. org/10.18820/2519593X/pie. v35i1.10"
- Description: Research is conceptualised in multiple and contradictory ways within and across Historically Black Universities (HBUs) with consequences for knowledge production. Under the apartheid regime, research was deliberately underdeveloped in such institutions and this continues to have an impact. We argue that if HBUs are to move from the constraints of the past into the possibilities of the future, there is a need for a thorough understanding both of how research is currently conceptualised, and of the consequences of such conceptions for research output. We used a critical discourse analysis of interviews, documents and survey data from seven HBUs to identify the dominant discourses about the purposes of research. The findings are four dominant conceptions of research that sometimes contradict each other across and within the HBUs. These are research as integral to academic identity; research for social justice; research as an economic driver and research as an instrumentalist requirement for job security, promotion and incentives. These conceptions seemed to emerge in part because of the history of the institutions and create both constraining and enabling effects on research production.
- Full Text:
- Date Issued: 2017
The contribution of NTFP trade to rural livelihoods in different agro-ecological zones of South Africa
- Mugido, Worship, Shackleton, Charlie M
- Authors: Mugido, Worship , Shackleton, Charlie M
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/398370 , vital:69404 , xlink:href="https://doi.org/10.1505/146554817821865063"
- Description: In South Africa, there is extensive NTFP trade within communities and via external markets. However, there is a limited indication of the proportion of all households trading one or more NTFPs, and how it varies in relation to local context. Therefore, this study sought to establish the proportion of households trading in NTFPs in sites of different distances to urban markets and agro-ecological zones of South Africa. The results showed that about 6.4% households reported selling NTFPs for various reasons, with many (22%) citing the need to earn cash income and limited employment opportunities (16.9%). Even though the returns from trading NTFPs are relatively low, every earning is very important to many cash-strapped rural households. This was demonstrated by the fact that many sellers of NTFPs used their earnings to augment household income and cover their living expenses.
- Full Text: false
- Date Issued: 2017
- Authors: Mugido, Worship , Shackleton, Charlie M
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/398370 , vital:69404 , xlink:href="https://doi.org/10.1505/146554817821865063"
- Description: In South Africa, there is extensive NTFP trade within communities and via external markets. However, there is a limited indication of the proportion of all households trading one or more NTFPs, and how it varies in relation to local context. Therefore, this study sought to establish the proportion of households trading in NTFPs in sites of different distances to urban markets and agro-ecological zones of South Africa. The results showed that about 6.4% households reported selling NTFPs for various reasons, with many (22%) citing the need to earn cash income and limited employment opportunities (16.9%). Even though the returns from trading NTFPs are relatively low, every earning is very important to many cash-strapped rural households. This was demonstrated by the fact that many sellers of NTFPs used their earnings to augment household income and cover their living expenses.
- Full Text: false
- Date Issued: 2017
The creation and validation of aptamers binding to murine 3T3-L1 Preadipocytes: preliminary implications for controlled cellular attachment, differentiation and cell fate
- Authors: Rubidge, Mark Lourens
- Date: 2017
- Subjects: Oligonucleotides , Fat cells , Stem cells , Ligand binding (Biochemistry) , Fluorimetry
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/65247 , vital:28714
- Description: The controlled seeding of a variety of stem cells in vitro has been reported to alter the patterns of their subsequent differentiation. This has been attributed to the control of the surface microenvironment onto which adherent stem cells are cultured, especially control of the proximal density of neighbouring cells. Simultaneously, advances in the generation of aptamers - synthetic ligand molecules developed using in vitro selection techniques targeting complex molecules - have aided in the production of molecules capable of selectively binding to a variety of commercial stem cell lines. Combining the aforementioned research fields, the project reported in this thesis aimed to generate DNA-based aptamers capable of assisting with the selective binding of murine 3T3- L1 preadipocytes to a solid surface. This was performed with a view to, eventually, control the seeding densities of the adherent preadipocytes on the surface of the tissue culture dish in subsequent researchers. In the process of meeting this goal, several optimisations of the in vitro process by which aptamers binding to cells are generated (Cell-SELEX) were performed: an analysis into a variety of methods used for the removal of the single stranded aptamer candidate sequences attached to the surface of 3T3-L1 preadipocytes, a comparison of methods for the generation of single-stranded aptamer sequences from double-stranded DNA template molecules and a method for quantifying the removed ssDNA from the cell surface. Their use is further reported in this work. Initially, it was determined that a fluorimetric evaluation of the unbound single stranded DNA was the optimum technique to use to evaluate the relative amounts of aptamer DNA binding to target cells during cell-SELEX; this arose from the release of DNA, and other cell lysate contaminates, which interfered UV/ Vis quantification. The evaluation into different methods of ssDNA removal from the cell surface showed that although trypsinisation of the cells demonstrated the highest level of aptamer detachment (quantified by fluorimetry), there is a decrease the number of potential targets that aptamers could attach to. The most common method for detaching bound DNA aptamer molecules from cellular targets reported in literature, the use of high temperatures, was selected for cell-SELEX to increase the variability in potential target sites on the cell surface. Using techniques optimised in this work, fluorescently-tagged single-stranded oligonucleotide aptamers were later generated with a positive selection pressure to bind to the surface of the 3T3-L1 preadipocytes, but not to their differentiated adipocyte counterparts. After eight cycles of cell-SELEX, fluorescent spectroscopic analysis depicted a 74 % binding retention of the selection pool in the positive preadipocyte selection pool, as opposed to a 0.69 % binding of sequences to the negative differentiated preadipocytes. Following the isolation and identification of candidate sequences, seven separate sequences were identified as being successfully generated from the selection process. Bioinformatic characterisation of these placed sequenced aptamer candidates into two separate families, that were then analysed in opposition to each for their binding affinity toward each other. Using fluorescently-tagged sequences, the binding selectivity of the generated aptamers was validated using both epifluorescent microscopy and confocal microscopy. At this stage, an aptamer sequence selected from prior in-house research to serve as a negative control also demonstrated significant binding to the extracellular matrix of both preadipocytes and mature adipocytes. 5’-thiolated aptamer sequences were used to form self-assembled monolayers on the electrode surfaces of the impedimetric Roche xCELLigence Real-Time Cell Analysis. The use of aptamer sequences to capture the seeded preadipocytes, demonstrated a slight increase in the extent of binding of the preadipocytes to the gold electrode surface and produced some preliminary indications of alterations to the pattern and rate of subsequent differentiation in the preadipocytes. This provides preliminary evidence that aptamers developed to bind specifically to a stem cell line in vitro show potential to be used as to capture said cell when cast in a self- assembled monolayer assembly. This provides a future opportunity to control the seeding densities of the cells in vitro. The effects of cellular differentiation at a set of predefined cellular densities can be demonstrated on a desired stem cell line. , Thesis (MSc) -- Faculty of Faculty of Science, Biotechnology Innovation Centre, 2017
- Full Text:
- Date Issued: 2017
- Authors: Rubidge, Mark Lourens
- Date: 2017
- Subjects: Oligonucleotides , Fat cells , Stem cells , Ligand binding (Biochemistry) , Fluorimetry
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/65247 , vital:28714
- Description: The controlled seeding of a variety of stem cells in vitro has been reported to alter the patterns of their subsequent differentiation. This has been attributed to the control of the surface microenvironment onto which adherent stem cells are cultured, especially control of the proximal density of neighbouring cells. Simultaneously, advances in the generation of aptamers - synthetic ligand molecules developed using in vitro selection techniques targeting complex molecules - have aided in the production of molecules capable of selectively binding to a variety of commercial stem cell lines. Combining the aforementioned research fields, the project reported in this thesis aimed to generate DNA-based aptamers capable of assisting with the selective binding of murine 3T3- L1 preadipocytes to a solid surface. This was performed with a view to, eventually, control the seeding densities of the adherent preadipocytes on the surface of the tissue culture dish in subsequent researchers. In the process of meeting this goal, several optimisations of the in vitro process by which aptamers binding to cells are generated (Cell-SELEX) were performed: an analysis into a variety of methods used for the removal of the single stranded aptamer candidate sequences attached to the surface of 3T3-L1 preadipocytes, a comparison of methods for the generation of single-stranded aptamer sequences from double-stranded DNA template molecules and a method for quantifying the removed ssDNA from the cell surface. Their use is further reported in this work. Initially, it was determined that a fluorimetric evaluation of the unbound single stranded DNA was the optimum technique to use to evaluate the relative amounts of aptamer DNA binding to target cells during cell-SELEX; this arose from the release of DNA, and other cell lysate contaminates, which interfered UV/ Vis quantification. The evaluation into different methods of ssDNA removal from the cell surface showed that although trypsinisation of the cells demonstrated the highest level of aptamer detachment (quantified by fluorimetry), there is a decrease the number of potential targets that aptamers could attach to. The most common method for detaching bound DNA aptamer molecules from cellular targets reported in literature, the use of high temperatures, was selected for cell-SELEX to increase the variability in potential target sites on the cell surface. Using techniques optimised in this work, fluorescently-tagged single-stranded oligonucleotide aptamers were later generated with a positive selection pressure to bind to the surface of the 3T3-L1 preadipocytes, but not to their differentiated adipocyte counterparts. After eight cycles of cell-SELEX, fluorescent spectroscopic analysis depicted a 74 % binding retention of the selection pool in the positive preadipocyte selection pool, as opposed to a 0.69 % binding of sequences to the negative differentiated preadipocytes. Following the isolation and identification of candidate sequences, seven separate sequences were identified as being successfully generated from the selection process. Bioinformatic characterisation of these placed sequenced aptamer candidates into two separate families, that were then analysed in opposition to each for their binding affinity toward each other. Using fluorescently-tagged sequences, the binding selectivity of the generated aptamers was validated using both epifluorescent microscopy and confocal microscopy. At this stage, an aptamer sequence selected from prior in-house research to serve as a negative control also demonstrated significant binding to the extracellular matrix of both preadipocytes and mature adipocytes. 5’-thiolated aptamer sequences were used to form self-assembled monolayers on the electrode surfaces of the impedimetric Roche xCELLigence Real-Time Cell Analysis. The use of aptamer sequences to capture the seeded preadipocytes, demonstrated a slight increase in the extent of binding of the preadipocytes to the gold electrode surface and produced some preliminary indications of alterations to the pattern and rate of subsequent differentiation in the preadipocytes. This provides preliminary evidence that aptamers developed to bind specifically to a stem cell line in vitro show potential to be used as to capture said cell when cast in a self- assembled monolayer assembly. This provides a future opportunity to control the seeding densities of the cells in vitro. The effects of cellular differentiation at a set of predefined cellular densities can be demonstrated on a desired stem cell line. , Thesis (MSc) -- Faculty of Faculty of Science, Biotechnology Innovation Centre, 2017
- Full Text:
- Date Issued: 2017
The effect of point of substitution and silver based nanoparticles on the photophysical and optical nonlinearity of indium carboxyphenoxy phthalocyanine
- Oluwole, David O, Ngxeke, Sixolisile M, Britton, Jonathan, Nyokong, Tebello
- Authors: Oluwole, David O , Ngxeke, Sixolisile M , Britton, Jonathan , Nyokong, Tebello
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188596 , vital:44768 , xlink:href="https://doi.org/10.1016/j.jphotochem.2017.07.032"
- Description: Indium(III) chloride 1,8(11),15(18),22(25)-tetra-(3-carboxyphenoxy) phthalocyanine (1) and indium(III) chloride 2,9(10),16(17),23(24)-tetra–(3-carboxyphenoxy) phthalocyanine (2) were covalently linked to glutathione capped silver nanoparticles (AgNPs–GSH) and silver selenide/zinc sulfide (Ag2Se/ZnS–GSH) quantum dots via amide bond formation. The photophysical and nonlinear optical behaviour of the metallophthalocyanines and their conjugates with nanoparticles were investigated using the open aperture Z–scan technique. Complex 2 showed enhanced photophysical properties compared to 1. The conjugates revealed improved triplet state quantum yields (except for 1-AgNPs-GSH which afforded lower triplet state quantum yields in comparison to 1) and nonlinear optical activities in comparison to the Pc complexes. The synthesized complexes, nanoparticles and their conjugates could be potential nonlinear optical materials due to their good nonlinear optical activities.
- Full Text:
- Date Issued: 2017
- Authors: Oluwole, David O , Ngxeke, Sixolisile M , Britton, Jonathan , Nyokong, Tebello
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188596 , vital:44768 , xlink:href="https://doi.org/10.1016/j.jphotochem.2017.07.032"
- Description: Indium(III) chloride 1,8(11),15(18),22(25)-tetra-(3-carboxyphenoxy) phthalocyanine (1) and indium(III) chloride 2,9(10),16(17),23(24)-tetra–(3-carboxyphenoxy) phthalocyanine (2) were covalently linked to glutathione capped silver nanoparticles (AgNPs–GSH) and silver selenide/zinc sulfide (Ag2Se/ZnS–GSH) quantum dots via amide bond formation. The photophysical and nonlinear optical behaviour of the metallophthalocyanines and their conjugates with nanoparticles were investigated using the open aperture Z–scan technique. Complex 2 showed enhanced photophysical properties compared to 1. The conjugates revealed improved triplet state quantum yields (except for 1-AgNPs-GSH which afforded lower triplet state quantum yields in comparison to 1) and nonlinear optical activities in comparison to the Pc complexes. The synthesized complexes, nanoparticles and their conjugates could be potential nonlinear optical materials due to their good nonlinear optical activities.
- Full Text:
- Date Issued: 2017
The effects of expansive shrubs on plant species richness and soils in semi-arid communal lands, South Africa
- Sholto-Douglas, Craig, Shackleton, Charlie M, Ruwanza, Sheunesu, Dold, Tony
- Authors: Sholto-Douglas, Craig , Shackleton, Charlie M , Ruwanza, Sheunesu , Dold, Tony
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/398394 , vital:69408 , xlink:href="https://doi.org/10.1002/ldr.2745"
- Description: Expansion by expansive species can have severe ecological, social and economic impacts through the reduction of ecosystem goods and services and species richness. However, expansion by expansive species may also offer benefits to ecosystems and humans, through the supply of ecosystem goods and services (such as firewood, fodder and fruits), as well as potentially offering refugia in heavily used landscapes. Here, we examine the effects of four expansive dwarf shrub species (Aspalathus subtingens, Dicerothamnus rhinocerotis, Pteronia incana and Oedera genistifolia) on plant species richness (at the point scale), vegetation cover, soil properties and whether the expansive species offer refugia to other species. Plant species richness, cover and soil properties were recorded in 1-m2 quadrats located within a mosaic of expanded and non-expanded patches for the four expansive shrub species. Plant species richness was significantly higher in the non-expanded areas compared to the expanded ones for all four expansive species. Some of the expansive shrubs provided refugia to certain plant species and limited the frequency of other species. With regard to species composition, there was little separation of expanded and non-expanded samples within sites, indicating that the site factors were stronger determinants of plant species richness and composition than expansion. Therefore, it is more likely that the reduction in species richness in expanded sites is caused by multiple drivers, including vegetation attributes cover, litter cover and soil nutrients (organic C, Zn and P) and soil compaction.
- Full Text:
- Date Issued: 2017
- Authors: Sholto-Douglas, Craig , Shackleton, Charlie M , Ruwanza, Sheunesu , Dold, Tony
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/398394 , vital:69408 , xlink:href="https://doi.org/10.1002/ldr.2745"
- Description: Expansion by expansive species can have severe ecological, social and economic impacts through the reduction of ecosystem goods and services and species richness. However, expansion by expansive species may also offer benefits to ecosystems and humans, through the supply of ecosystem goods and services (such as firewood, fodder and fruits), as well as potentially offering refugia in heavily used landscapes. Here, we examine the effects of four expansive dwarf shrub species (Aspalathus subtingens, Dicerothamnus rhinocerotis, Pteronia incana and Oedera genistifolia) on plant species richness (at the point scale), vegetation cover, soil properties and whether the expansive species offer refugia to other species. Plant species richness, cover and soil properties were recorded in 1-m2 quadrats located within a mosaic of expanded and non-expanded patches for the four expansive shrub species. Plant species richness was significantly higher in the non-expanded areas compared to the expanded ones for all four expansive species. Some of the expansive shrubs provided refugia to certain plant species and limited the frequency of other species. With regard to species composition, there was little separation of expanded and non-expanded samples within sites, indicating that the site factors were stronger determinants of plant species richness and composition than expansion. Therefore, it is more likely that the reduction in species richness in expanded sites is caused by multiple drivers, including vegetation attributes cover, litter cover and soil nutrients (organic C, Zn and P) and soil compaction.
- Full Text:
- Date Issued: 2017
The effects of rhizobium inoculation on growth performance, forage production, nutrient and anti-nutrient content of lablab purpureus cultivars
- Senti, Sibongile Portia https://orcid.org/0000-0003-4906-9570
- Authors: Senti, Sibongile Portia https://orcid.org/0000-0003-4906-9570
- Date: 2017
- Subjects: Livestock productivity , Rhizobium japonicum
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/22864 , vital:53011
- Description: Declining soil fertility and inadequate low quality feed resources limit smallholder livestock production in the semi-arid regions of Eastern Cape in South Africa. Smallholder farmers are facing problems of high cost of artificial fertilisers limiting them in production of cereal crops and also fodder for their livestock. This leads to poor nutrition, particularly in the dry season, it affects livestock production. Planting Lablab purpureus and inoculating with Rhizobium would limit the necessity for buying expensive protein supplements and nitrogen fertilisers. Lablab purpureus can provide feed in the dry season for the improvement of livestock production. The objective of this study was to investigate the effect of Bradyrhizobium japonicum inoculation on growth performance, biomass production, nutrient and anti-nutrient content of the two Lablab purpureus cultivars (Rongai and Highworth). The experiment was conducted at Fort Hare Research Farm in Alice, South Africa. Data was collected on plant seedling emergence, plant height, stem diameter, plant vigour, chlorophyll content, nodule numbers as well as dry matter content, biomass yield, nutrient and anti-nutrient contents at 30, 60 and 90 DAP. Samples of Lablab purpureus were harvested at flowering stage and analysed for dry matter content, biomass yield, chemical, mineral and anti-ntrient composition. The results showed that Rhizobium inoculation significantly increased (p<0.05) seedling emergence, plant height and stem diameter of both Lablab purpureus cultivars. Rhizobium inoculation had no significant effect (p>0.05) on chlorophyll content for both cultivars. Highworth had significantly higher (p<0.05) plant vigour than Rongai on both inoculated and uninoculated. Varieties and inoculation effects were significant (p<0.05) for number of nodules, nodulation rate, active nodules and nodule dry yield. Rhizobium inoculation significantly (p<0.05) increased fresh matter yield, dry matter yied and dry matter content on both cultivars. There were no significant differences (p>0.05) in NDF, ADIN, ADL, ADF, and Na between inoculated and uninoculated plants for both cultivars. The inoculation of Rhizobium improved CP (15.65%) in Highworth cultivar. The inoculation of Rhizobium significantly increased Ca (1.76-1.84%), Zn (191.91-2 8.33ppm) and Cu (3.50-6.16ppm) compared to un-inoculated plants. Varieties and Rhizobium had no interaction (p>0.05) with condensed tannin, hydrolysable tannin, total polyphenols and saponins . Therefore, the Rhizobium inoculation assisted in improving quality in terms of nutrient composition and decreasing anti-nutrients. It is recommended to use both cultivars of Lablab purpureus. Based on the results of this study it is concluded that Rhizobium inoculation increases yield and forage quality of Lablab purpureus. It is recommended that Highworth cultivar can be used by communal farmers in the Eastern Cape. This cultivar showed that it needs Rhizobium inoculation inorder to produce high quality that can increase livestock production. , Thesis (MSc) -- Faculty of Science and Agriculture, 2017
- Full Text:
- Date Issued: 2017
- Authors: Senti, Sibongile Portia https://orcid.org/0000-0003-4906-9570
- Date: 2017
- Subjects: Livestock productivity , Rhizobium japonicum
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/22864 , vital:53011
- Description: Declining soil fertility and inadequate low quality feed resources limit smallholder livestock production in the semi-arid regions of Eastern Cape in South Africa. Smallholder farmers are facing problems of high cost of artificial fertilisers limiting them in production of cereal crops and also fodder for their livestock. This leads to poor nutrition, particularly in the dry season, it affects livestock production. Planting Lablab purpureus and inoculating with Rhizobium would limit the necessity for buying expensive protein supplements and nitrogen fertilisers. Lablab purpureus can provide feed in the dry season for the improvement of livestock production. The objective of this study was to investigate the effect of Bradyrhizobium japonicum inoculation on growth performance, biomass production, nutrient and anti-nutrient content of the two Lablab purpureus cultivars (Rongai and Highworth). The experiment was conducted at Fort Hare Research Farm in Alice, South Africa. Data was collected on plant seedling emergence, plant height, stem diameter, plant vigour, chlorophyll content, nodule numbers as well as dry matter content, biomass yield, nutrient and anti-nutrient contents at 30, 60 and 90 DAP. Samples of Lablab purpureus were harvested at flowering stage and analysed for dry matter content, biomass yield, chemical, mineral and anti-ntrient composition. The results showed that Rhizobium inoculation significantly increased (p<0.05) seedling emergence, plant height and stem diameter of both Lablab purpureus cultivars. Rhizobium inoculation had no significant effect (p>0.05) on chlorophyll content for both cultivars. Highworth had significantly higher (p<0.05) plant vigour than Rongai on both inoculated and uninoculated. Varieties and inoculation effects were significant (p<0.05) for number of nodules, nodulation rate, active nodules and nodule dry yield. Rhizobium inoculation significantly (p<0.05) increased fresh matter yield, dry matter yied and dry matter content on both cultivars. There were no significant differences (p>0.05) in NDF, ADIN, ADL, ADF, and Na between inoculated and uninoculated plants for both cultivars. The inoculation of Rhizobium improved CP (15.65%) in Highworth cultivar. The inoculation of Rhizobium significantly increased Ca (1.76-1.84%), Zn (191.91-2 8.33ppm) and Cu (3.50-6.16ppm) compared to un-inoculated plants. Varieties and Rhizobium had no interaction (p>0.05) with condensed tannin, hydrolysable tannin, total polyphenols and saponins . Therefore, the Rhizobium inoculation assisted in improving quality in terms of nutrient composition and decreasing anti-nutrients. It is recommended to use both cultivars of Lablab purpureus. Based on the results of this study it is concluded that Rhizobium inoculation increases yield and forage quality of Lablab purpureus. It is recommended that Highworth cultivar can be used by communal farmers in the Eastern Cape. This cultivar showed that it needs Rhizobium inoculation inorder to produce high quality that can increase livestock production. , Thesis (MSc) -- Faculty of Science and Agriculture, 2017
- Full Text:
- Date Issued: 2017
The impact of preventive family-strengthening programmes on family cohesion in the Buffalo City Metropolitan Municipality
- Nyanhoto, Rumbidzai https://orcid.org/0000-0002-8505-9890
- Authors: Nyanhoto, Rumbidzai https://orcid.org/0000-0002-8505-9890
- Date: 2017
- Subjects: Family social work http://id.loc.gov/authorities/subjects/sh85047068 , Social service http://id.loc.gov/authorities/subjects/sh85124049 , Social problems http://id.loc.gov/authorities/subjects/sh85123988
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/19487 , vital:43132
- Description: This study focused on the impact which specific selected preventive family-strengthening programmes in the Buffalo City Metropolitan Municipality in the Eastern Cape province of South Africa have on improving family cohesion. A mixed methods approach was used to collect and analyse the data. The quantitative approach was the dominant one, while a qualitative approach was used to corroborate the quantitative findings. The quantitative data was collected through a survey. One hundred questionnaires were distributed among the beneficiaries of selected preventive family-strengthening programmes, which were parenting and marriage enrichment programmes. The beneficiaries of the programmes were selected through simple random sampling from the databases of the NGOs which had agreed to participate in the study. The qualitative component of the study produced results which supported the quantitative findings. This data was collected through in-depth interviews which were conducted with fifteen purposively selected social workers who were involved in the implementation of the selected preventive family-strengthening programmes. The findings of the study indicated that although both of the parenting and marriage enrichment programmes do cater for the common problems which affect families, in many cases they do not appear to meet the expectations of their intended beneficiaries. The study found that of the 10 objectives of the parenting programme, only 6 were being met. The programme was found to have achieved its objective of helping parents to understand the behaviour of their children, to be sensitive to their feelings, to develop their self-esteem, to communicate effectively with them, to build the family and to understand their rights with respect to grants. However, the beneficiaries who attended the programme were still unable to encourage self-discipline, to talk to their children about sexuality, to prevent instances of violence in their families or to deal with problems pertaining to child abuse, which represents a failure to meet four of the specific objectives of the programme. The marriage enrichment programme was found to have met its objectives to help couples to assess strength and growth areas, to strengthen their communication skills and to develop personal goals, goals for themselves as couples and goals for their families. The objectives of helping couples to resolve conflicts constructively, to resolve problems pertaining to their families of origin and develop workable budgets or financial plans between spouses were not being met, as the findings indicated that most of the beneficiaries were still struggling to meet these three specific objectives. Their failures in these domains could be attributed to the perceptions which their African culture had instilled in the beneficiaries. The results of the study also indicated that attending the preventive family-strengthening programmes had strengthened the cohesion of families. The discernible evidence of cohesion in the families of most of the beneficiaries who had attended the programmes was expressed through shared affection, a sense of loyalty, reciprocity, solidarity within families and shared decision making. On the basis of the findings, it is recommended that the government should provide adequate means to facilitate the implementation of the programmes, to facilitate partnerships among stakeholders and to ensure the continuous monitoring and evaluation of the programmes. It is also recommended that in order to meet the vii expectations of the beneficiaries of the programmes, needs assessments which engage the communities in the reviewing of the content of the programmes should be performed. In social work practice, the indigenisation of the programmes and the incorporation of the spill over hypothesis will promote their effective implementation. , Thesis (PhD) (Social Work) -- University of Fort Hare, 2017
- Full Text:
- Date Issued: 2017
- Authors: Nyanhoto, Rumbidzai https://orcid.org/0000-0002-8505-9890
- Date: 2017
- Subjects: Family social work http://id.loc.gov/authorities/subjects/sh85047068 , Social service http://id.loc.gov/authorities/subjects/sh85124049 , Social problems http://id.loc.gov/authorities/subjects/sh85123988
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/19487 , vital:43132
- Description: This study focused on the impact which specific selected preventive family-strengthening programmes in the Buffalo City Metropolitan Municipality in the Eastern Cape province of South Africa have on improving family cohesion. A mixed methods approach was used to collect and analyse the data. The quantitative approach was the dominant one, while a qualitative approach was used to corroborate the quantitative findings. The quantitative data was collected through a survey. One hundred questionnaires were distributed among the beneficiaries of selected preventive family-strengthening programmes, which were parenting and marriage enrichment programmes. The beneficiaries of the programmes were selected through simple random sampling from the databases of the NGOs which had agreed to participate in the study. The qualitative component of the study produced results which supported the quantitative findings. This data was collected through in-depth interviews which were conducted with fifteen purposively selected social workers who were involved in the implementation of the selected preventive family-strengthening programmes. The findings of the study indicated that although both of the parenting and marriage enrichment programmes do cater for the common problems which affect families, in many cases they do not appear to meet the expectations of their intended beneficiaries. The study found that of the 10 objectives of the parenting programme, only 6 were being met. The programme was found to have achieved its objective of helping parents to understand the behaviour of their children, to be sensitive to their feelings, to develop their self-esteem, to communicate effectively with them, to build the family and to understand their rights with respect to grants. However, the beneficiaries who attended the programme were still unable to encourage self-discipline, to talk to their children about sexuality, to prevent instances of violence in their families or to deal with problems pertaining to child abuse, which represents a failure to meet four of the specific objectives of the programme. The marriage enrichment programme was found to have met its objectives to help couples to assess strength and growth areas, to strengthen their communication skills and to develop personal goals, goals for themselves as couples and goals for their families. The objectives of helping couples to resolve conflicts constructively, to resolve problems pertaining to their families of origin and develop workable budgets or financial plans between spouses were not being met, as the findings indicated that most of the beneficiaries were still struggling to meet these three specific objectives. Their failures in these domains could be attributed to the perceptions which their African culture had instilled in the beneficiaries. The results of the study also indicated that attending the preventive family-strengthening programmes had strengthened the cohesion of families. The discernible evidence of cohesion in the families of most of the beneficiaries who had attended the programmes was expressed through shared affection, a sense of loyalty, reciprocity, solidarity within families and shared decision making. On the basis of the findings, it is recommended that the government should provide adequate means to facilitate the implementation of the programmes, to facilitate partnerships among stakeholders and to ensure the continuous monitoring and evaluation of the programmes. It is also recommended that in order to meet the vii expectations of the beneficiaries of the programmes, needs assessments which engage the communities in the reviewing of the content of the programmes should be performed. In social work practice, the indigenisation of the programmes and the incorporation of the spill over hypothesis will promote their effective implementation. , Thesis (PhD) (Social Work) -- University of Fort Hare, 2017
- Full Text:
- Date Issued: 2017
The photophysical studies of Pluronic F127/P123 micelle mixture system loaded with metal free and Zn 5, 10, 15, 20-tetrakis [4-(benzyloxy) phenyl] porphyrins
- Managa, Muthumuni, Ngoy, Bokolombe P, Nyokong, Tebello
- Authors: Managa, Muthumuni , Ngoy, Bokolombe P , Nyokong, Tebello
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188932 , vital:44799 , xlink:href="https://doi.org/10.1016/j.jphotochem.2017.02.018"
- Description: Binary mixtures of Pluronics are studied as drug nanocarriers in this work. H2 and Zn 5,10,15,20-tetrakis[4-(benzyloxy) phenyl] porphyrin were encapsulated onto binary micelle mixture of Pluronic F127/P123. The fluorescence and singlet oxygen generating behaviour of the porphyrins were investigated following incorporation. The fluorescence quantum yield for H2TBnOPP (ΦF = 0.034) was higher than that of ZnTBnOPP (ΦF = 0.023) and decreased when ZnTBnOPP or H2TBnOPP when in the presence of Pluronic F127/P123 binary mixtures. The kq values were 2.8 × 108 and 3.7 × 108 M−1 s−1, for H2TBnOPP + Pluronic F127/P123 and ZnTBnOPP + Pluronic F127/P123 in water, respectively. The binding constants (Kb) were 1.58 × 105 M−1 and 1.02 × 105 M−1 for ZnTBnOPP + Pluronic F127/P123 and H2TBnOPP + Pluronic F127/P123, respectively.
- Full Text:
- Date Issued: 2017
- Authors: Managa, Muthumuni , Ngoy, Bokolombe P , Nyokong, Tebello
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188932 , vital:44799 , xlink:href="https://doi.org/10.1016/j.jphotochem.2017.02.018"
- Description: Binary mixtures of Pluronics are studied as drug nanocarriers in this work. H2 and Zn 5,10,15,20-tetrakis[4-(benzyloxy) phenyl] porphyrin were encapsulated onto binary micelle mixture of Pluronic F127/P123. The fluorescence and singlet oxygen generating behaviour of the porphyrins were investigated following incorporation. The fluorescence quantum yield for H2TBnOPP (ΦF = 0.034) was higher than that of ZnTBnOPP (ΦF = 0.023) and decreased when ZnTBnOPP or H2TBnOPP when in the presence of Pluronic F127/P123 binary mixtures. The kq values were 2.8 × 108 and 3.7 × 108 M−1 s−1, for H2TBnOPP + Pluronic F127/P123 and ZnTBnOPP + Pluronic F127/P123 in water, respectively. The binding constants (Kb) were 1.58 × 105 M−1 and 1.02 × 105 M−1 for ZnTBnOPP + Pluronic F127/P123 and H2TBnOPP + Pluronic F127/P123, respectively.
- Full Text:
- Date Issued: 2017
The relevance of cross-scale connections and spatial interactions for ecosystem service delivery by protected areas: Insights from southern Africa
- de Vos, Alta, Cumming, Graeme S, Roux, Dirk J
- Authors: de Vos, Alta , Cumming, Graeme S , Roux, Dirk J
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/416438 , vital:71348 , xlink:href="https://doi.org/10.1016/j.ecoser.2017.11.014"
- Description: The ecosystem services (ES) concept can frame the value of protected areas (PAs) to society and identify management actions that bridge biodiversity conservation and human benefits. In this special issue on ES flows to and from southern African PAs we consider two themes: (1) water as a biophysical and social-ecological connector; and (2) cross-scale interactions and connections as influences on cultural ecosystem service (CES) provision. Freshwater flows have supporting, regulating, and cultural elements, leading to complexities in governance as well as place attachment, intellectual, and recreational services. Scale dependence in CES creates trade-offs that challenge the usefulness of the ES framework for PA management. Ecosystem service production can potentially create political support for PAs and helps to build connections and feedbacks that increase PA resilience. Papers in the feature highlight a need to understand trade-offs in optimising for biodiversity vs. particular bundles of ES; impacts of investment in built infrastructure on ES use; how managers facilitate ES; scale and heterogeneity as influences; the role of adaptive monitoring of PAs as social–ecological systems; and services and benefits from PAs that are not well-articulated in ES classifications. PA research can thus add nuance, depth and substance to broader thinking around CES.
- Full Text:
- Date Issued: 2017
- Authors: de Vos, Alta , Cumming, Graeme S , Roux, Dirk J
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/416438 , vital:71348 , xlink:href="https://doi.org/10.1016/j.ecoser.2017.11.014"
- Description: The ecosystem services (ES) concept can frame the value of protected areas (PAs) to society and identify management actions that bridge biodiversity conservation and human benefits. In this special issue on ES flows to and from southern African PAs we consider two themes: (1) water as a biophysical and social-ecological connector; and (2) cross-scale interactions and connections as influences on cultural ecosystem service (CES) provision. Freshwater flows have supporting, regulating, and cultural elements, leading to complexities in governance as well as place attachment, intellectual, and recreational services. Scale dependence in CES creates trade-offs that challenge the usefulness of the ES framework for PA management. Ecosystem service production can potentially create political support for PAs and helps to build connections and feedbacks that increase PA resilience. Papers in the feature highlight a need to understand trade-offs in optimising for biodiversity vs. particular bundles of ES; impacts of investment in built infrastructure on ES use; how managers facilitate ES; scale and heterogeneity as influences; the role of adaptive monitoring of PAs as social–ecological systems; and services and benefits from PAs that are not well-articulated in ES classifications. PA research can thus add nuance, depth and substance to broader thinking around CES.
- Full Text:
- Date Issued: 2017
The Role of HOP in Emerin-Mediated Nuclear Structure
- Authors: Kituyi, Sarah Naulikha
- Date: 2017
- Subjects: Heat shock proteins , Nuclear structure , Nuclear membranes , Cancer Treatment , Molecular chaperones , Cytoskeleton , Cytoplasm
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/59230 , vital:27485 , DOI 10.21504/10962/59230
- Description: A vital component of the integral nuclear membrane is emerin, a Lamin Emerin and Man1 (LEM) domain protein whose concentration determines the levels of partner proteins that together constitute the structure of the nuclear envelope. Deficiencies in any of these proteins causes the failure of the structure and assembly and disassembly of the nuclear envelope, which disrupts chromosome segregation and nuclear compartmentalization that are both associated with disease. Emerin also localizes in the cytoplasm where it is implicated in the structure of the cytoskeleton via interaction with tubulin and actin and thus its deficiency may equally contribute to the collapse of the cytoskeleton. The Hsp70-Hsp90 organising protein (Hop) functions as a cochaperone for entry of client proteins into the Hsp90 folding cycle. Hop is upregulated in cancer and regulates a number of cell biology processes via interactions with proteins independently of Hsp90. In a previous study using global whole cell mass spectrometry, emerin was shown to be the most significantly down regulated protein in Hop depleted cell lysates. In this current study, it was postulated that emerin interacts with Hop, and this interaction regulates the stability, and level of emerin in the nucleus which impacts on the structure of the nuclear envelope. We used HEK293T cell lines stably expressing shRNA against Hop, emerin and a non-targeting control alongside the over expression of Hop in HEK293 cells to determine the effect of Hop levels on emerin expression and vice versa via Western blotting. The effect of Hop on the localization of emerin was assessed via subcellullar fractionation and confocal microscopy, while the impact on the structure of the nucleus was determined by transmission electron microscopy (TEM). We established that the depletion of Hop using shRNA and the over expression of Hop both result in the proteasomal and lysosomal degradation of emerin. Co-immunoprecipitation assays confirmed that Hop and emerin are in a common complex, which was not dependent on the presence of Hsp90. Loss of Hop or emerin led to a deformation of nuclear structure and a statistically significant decrease in nuclear size compared to control cells and was associated with an increase in the levels of nuclear protein, lamin A-C. Loss of emerin and Hop resulted in increased long term cell survival, but only after restriction of the nucleus when the cells had migrated across a transwell membrane. Taken together, the results obtained suggest that Hop acts as a scaffold for the stabilization of emerin and that the effects of Hop depletion on the structure of the nucleus and long term survival are mediated via the depletion of emerin. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2017
- Full Text:
- Date Issued: 2017
- Authors: Kituyi, Sarah Naulikha
- Date: 2017
- Subjects: Heat shock proteins , Nuclear structure , Nuclear membranes , Cancer Treatment , Molecular chaperones , Cytoskeleton , Cytoplasm
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/59230 , vital:27485 , DOI 10.21504/10962/59230
- Description: A vital component of the integral nuclear membrane is emerin, a Lamin Emerin and Man1 (LEM) domain protein whose concentration determines the levels of partner proteins that together constitute the structure of the nuclear envelope. Deficiencies in any of these proteins causes the failure of the structure and assembly and disassembly of the nuclear envelope, which disrupts chromosome segregation and nuclear compartmentalization that are both associated with disease. Emerin also localizes in the cytoplasm where it is implicated in the structure of the cytoskeleton via interaction with tubulin and actin and thus its deficiency may equally contribute to the collapse of the cytoskeleton. The Hsp70-Hsp90 organising protein (Hop) functions as a cochaperone for entry of client proteins into the Hsp90 folding cycle. Hop is upregulated in cancer and regulates a number of cell biology processes via interactions with proteins independently of Hsp90. In a previous study using global whole cell mass spectrometry, emerin was shown to be the most significantly down regulated protein in Hop depleted cell lysates. In this current study, it was postulated that emerin interacts with Hop, and this interaction regulates the stability, and level of emerin in the nucleus which impacts on the structure of the nuclear envelope. We used HEK293T cell lines stably expressing shRNA against Hop, emerin and a non-targeting control alongside the over expression of Hop in HEK293 cells to determine the effect of Hop levels on emerin expression and vice versa via Western blotting. The effect of Hop on the localization of emerin was assessed via subcellullar fractionation and confocal microscopy, while the impact on the structure of the nucleus was determined by transmission electron microscopy (TEM). We established that the depletion of Hop using shRNA and the over expression of Hop both result in the proteasomal and lysosomal degradation of emerin. Co-immunoprecipitation assays confirmed that Hop and emerin are in a common complex, which was not dependent on the presence of Hsp90. Loss of Hop or emerin led to a deformation of nuclear structure and a statistically significant decrease in nuclear size compared to control cells and was associated with an increase in the levels of nuclear protein, lamin A-C. Loss of emerin and Hop resulted in increased long term cell survival, but only after restriction of the nucleus when the cells had migrated across a transwell membrane. Taken together, the results obtained suggest that Hop acts as a scaffold for the stabilization of emerin and that the effects of Hop depletion on the structure of the nucleus and long term survival are mediated via the depletion of emerin. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2017
- Full Text:
- Date Issued: 2017
The safety net function of NTFPs in different agro-ecological zones of South Africa
- Mugido, Worship, Shackleton, Charlie M
- Authors: Mugido, Worship , Shackleton, Charlie M
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180111 , vital:43311 , xlink:href="https://doi.org/10.1007/s11111-017-0285-z"
- Description: Various South African studies have shown that rural households use NTFPs as safety nets in times of misfortune. However being focused on one or two sites, they do not show the prevalence of NTFP use as safety nets across multiple sites. In addition, they do not show the use of NTFPs as safety nets by rural households in different agro-ecological zones. The results of the study showed that about 79% of the total households interviewed experienced at least one shock of some magnitude in the previous 12 months. The most experienced shocks were illness, death, crop failure, and hunger. The households employed various coping strategies in response to different types of shocks, with the three widely used strategies being assistance from friends and relatives, using cash savings, and using NTFPs. Households in low agro-ecological zones used NTFPs as safety nets more than households in high agro-ecological zones.
- Full Text:
- Date Issued: 2017
- Authors: Mugido, Worship , Shackleton, Charlie M
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180111 , vital:43311 , xlink:href="https://doi.org/10.1007/s11111-017-0285-z"
- Description: Various South African studies have shown that rural households use NTFPs as safety nets in times of misfortune. However being focused on one or two sites, they do not show the prevalence of NTFP use as safety nets across multiple sites. In addition, they do not show the use of NTFPs as safety nets by rural households in different agro-ecological zones. The results of the study showed that about 79% of the total households interviewed experienced at least one shock of some magnitude in the previous 12 months. The most experienced shocks were illness, death, crop failure, and hunger. The households employed various coping strategies in response to different types of shocks, with the three widely used strategies being assistance from friends and relatives, using cash savings, and using NTFPs. Households in low agro-ecological zones used NTFPs as safety nets more than households in high agro-ecological zones.
- Full Text:
- Date Issued: 2017
The use of experimental design for the development of a capillary zone electrophoresis method for the quantitation of captopril
- Mukozhiwa, S Y, Khamanga, Sandile M, Walker, Roderick B
- Authors: Mukozhiwa, S Y , Khamanga, Sandile M , Walker, Roderick B
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183828 , vital:44073 , xlink:href="https://doi.org/10.1691/ph.2017.7071"
- Description: A capillary zone electrophoresis (CZE) method for the quantitation of captopril (CPT) using UV detection was developed. Influence of electrolyte concentration and system variables on electrophoretic separation was evaluated and a central composite design (CCD) was used to optimize the method. Variables investigated were pH, molarity, applied voltage and capillary length. The influence of sodium metabisulphite on the stability of test solutions was also investigated. The use of sodium metabisulphite prevented degradation of CPT over 24 hours. A fused uncoated silica capillary of 67.5cm total and 57.5 cm effective length was used for analysis. The applied voltage and capillary length affected the migration time of CPT significantly. A 20 mM phosphate buffer adjusted to pH 7.0 was used as running buffer and an applied voltage of 23.90 kV was suitable to effect a separation. The optimized electrophoretic conditions produced sharp, well-resolved peaks for CPT and sodium metabisulphite. Linear regression analysis of the response for CPT standards revealed the method was linear (R2 = 0.9995) over the range 5-70 μg/mL. The limits of quantitation and detection were 5 and 1.5 μg/mL. A simple, rapid and reliable CZE method has been developed and successfully applied to the analysis of commercially available CPT products.
- Full Text:
- Date Issued: 2017
- Authors: Mukozhiwa, S Y , Khamanga, Sandile M , Walker, Roderick B
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183828 , vital:44073 , xlink:href="https://doi.org/10.1691/ph.2017.7071"
- Description: A capillary zone electrophoresis (CZE) method for the quantitation of captopril (CPT) using UV detection was developed. Influence of electrolyte concentration and system variables on electrophoretic separation was evaluated and a central composite design (CCD) was used to optimize the method. Variables investigated were pH, molarity, applied voltage and capillary length. The influence of sodium metabisulphite on the stability of test solutions was also investigated. The use of sodium metabisulphite prevented degradation of CPT over 24 hours. A fused uncoated silica capillary of 67.5cm total and 57.5 cm effective length was used for analysis. The applied voltage and capillary length affected the migration time of CPT significantly. A 20 mM phosphate buffer adjusted to pH 7.0 was used as running buffer and an applied voltage of 23.90 kV was suitable to effect a separation. The optimized electrophoretic conditions produced sharp, well-resolved peaks for CPT and sodium metabisulphite. Linear regression analysis of the response for CPT standards revealed the method was linear (R2 = 0.9995) over the range 5-70 μg/mL. The limits of quantitation and detection were 5 and 1.5 μg/mL. A simple, rapid and reliable CZE method has been developed and successfully applied to the analysis of commercially available CPT products.
- Full Text:
- Date Issued: 2017
Tourism entrepreneurship: the contours of challenges faced by female-owned BnBs and Guesthouses in Mthatha, South Africa
- Hlanyane, Tabisa Monalisa, Acheampong, Kofi Owusu
- Authors: Hlanyane, Tabisa Monalisa , Acheampong, Kofi Owusu
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/6563 , vital:46659 , https://www.ajhtl.com/uploads/7/1/6/3/7163688/article_50_vol_6__4__2017.pdf
- Description: The purpose of the study was to investigate and discover the facts about the challenges of female entrepreneurs who are the owners of bed and breakfasts and guesthouses in Mthatha, and to find out whether these challenges have an impact in their business performance. By way of using a semi-structured survey, women who own guesthouses and bed and breakfast establishments were targeted by way of a purposive snowball sampling technique. The primary data collected indicated that female-entrepreneurs in Mthatha face a number of challenges including limited access to finance, seasonality, balancing work and family life, corruption/bribery, poor infrastructure, inability to attend seminars and workshops to network, poor customer service and lack of awareness to the required training/skills to function effectively. However, such women remain resilient to the aforementioned challenges, largely motivated by such factors linked to flexibility, the quest to remain independent and the belief in the opportunity and financial incentives that their operation represents. This study has implications for entrepreneurship and economic growth in South Africa and how vulnerable businesses including women’s require continuous support from government and private sector to remain competitive and economically sustainable.ackground:Context-specific factors influence adherence to antiretroviral therapy (ART) among pregnant womenliving with HIV. Gaps exist in the understanding of the reasons for the variable outcomes of the prevention ofmother-to-child transmission (PMTCT) programme at the health facility level in South Africa. This study examinedadherence levels and reasons for non-adherence during pregnancy in a cohort of parturient women enrolled in thePMTCT programme in the Eastern Cape, South Africa.Methods:This was a mixed-methods study involving 1709 parturient women in the Eastern Cape, South Africa. Weconducted a multi-centre retrospective analysis of the mother-infant pair in the PMTCT electronic database in 2016.Semi-structured interviews of purposively selected parturient women with self-reported poor adherence (n= 177)were conducted to gain understanding of the main barriers to adherence. Binary logistic regression was used todetermine the independent predictors of ART non-adherence.Results:A high proportion (69.0%) of women reported perfect adherence. In the logistic regression analysis, afteradjusting for confounding factors, marital status, cigarette smoking, alcohol use and non-disclosure to a family memberwere the independent predictors of non-adherence. Analysis of the qualitative data revealed that drug-related side-effects, being away from home, forgetfulness, non-disclosure, stigma and work-related demand were among the mainreasons for non-adherence to ART.Conclusions:Non-adherence to the antiretroviral therapy among pregnant women in this setting is associated withlifestyle behaviours, HIV-related stigma and ART side-effects. In order to eliminate mother-to-child transmission of HIV,clinicians need to screen for these factors at every antenatal clinic visit.Keywords:Adherence, Non-adherence, HIV, Antiretroviral therapy, Elimination of mother-to-child transmission,Prevention of mother-to-child transmission, Stigma, South Africa
- Full Text:
- Date Issued: 2017
- Authors: Hlanyane, Tabisa Monalisa , Acheampong, Kofi Owusu
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/6563 , vital:46659 , https://www.ajhtl.com/uploads/7/1/6/3/7163688/article_50_vol_6__4__2017.pdf
- Description: The purpose of the study was to investigate and discover the facts about the challenges of female entrepreneurs who are the owners of bed and breakfasts and guesthouses in Mthatha, and to find out whether these challenges have an impact in their business performance. By way of using a semi-structured survey, women who own guesthouses and bed and breakfast establishments were targeted by way of a purposive snowball sampling technique. The primary data collected indicated that female-entrepreneurs in Mthatha face a number of challenges including limited access to finance, seasonality, balancing work and family life, corruption/bribery, poor infrastructure, inability to attend seminars and workshops to network, poor customer service and lack of awareness to the required training/skills to function effectively. However, such women remain resilient to the aforementioned challenges, largely motivated by such factors linked to flexibility, the quest to remain independent and the belief in the opportunity and financial incentives that their operation represents. This study has implications for entrepreneurship and economic growth in South Africa and how vulnerable businesses including women’s require continuous support from government and private sector to remain competitive and economically sustainable.ackground:Context-specific factors influence adherence to antiretroviral therapy (ART) among pregnant womenliving with HIV. Gaps exist in the understanding of the reasons for the variable outcomes of the prevention ofmother-to-child transmission (PMTCT) programme at the health facility level in South Africa. This study examinedadherence levels and reasons for non-adherence during pregnancy in a cohort of parturient women enrolled in thePMTCT programme in the Eastern Cape, South Africa.Methods:This was a mixed-methods study involving 1709 parturient women in the Eastern Cape, South Africa. Weconducted a multi-centre retrospective analysis of the mother-infant pair in the PMTCT electronic database in 2016.Semi-structured interviews of purposively selected parturient women with self-reported poor adherence (n= 177)were conducted to gain understanding of the main barriers to adherence. Binary logistic regression was used todetermine the independent predictors of ART non-adherence.Results:A high proportion (69.0%) of women reported perfect adherence. In the logistic regression analysis, afteradjusting for confounding factors, marital status, cigarette smoking, alcohol use and non-disclosure to a family memberwere the independent predictors of non-adherence. Analysis of the qualitative data revealed that drug-related side-effects, being away from home, forgetfulness, non-disclosure, stigma and work-related demand were among the mainreasons for non-adherence to ART.Conclusions:Non-adherence to the antiretroviral therapy among pregnant women in this setting is associated withlifestyle behaviours, HIV-related stigma and ART side-effects. In order to eliminate mother-to-child transmission of HIV,clinicians need to screen for these factors at every antenatal clinic visit.Keywords:Adherence, Non-adherence, HIV, Antiretroviral therapy, Elimination of mother-to-child transmission,Prevention of mother-to-child transmission, Stigma, South Africa
- Full Text:
- Date Issued: 2017
Understanding spatial variation in the drivers of nature-based tourism and their influence on the sustainability of private land conservation
- Baum, Julia, Cumming, Graeme S, de Vos, Alta
- Authors: Baum, Julia , Cumming, Graeme S , de Vos, Alta
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/416481 , vital:71352 , xlink:href="https://doi.org/10.1016/j.ecolecon.2017.05.005"
- Description: Protected areas connect socio-economic and ecological systems through their provision of ecosystem goods and services. Analysis of ecosystem services allows the expression of ecological benefits in economic terms. However, cultural services, such as recreation opportunities, have proved difficult to quantify. An important challenge for the analysis of cultural services is to understand the geography of service provision in relation to both human and ecological system elements. We used data on visitation rates and measures of context, content, connectivity, and location for 64 private land conservation areas (PLCAs) to better understand geographic influences on cultural service provision. Visitation to PLCAs was influenced by a combination of ecological and socio-economic drivers. Variance partitioning analysis showed that ecology explained the largest proportion of overall variation in visitation rates (26%), followed by location (22%). In tests using generalized linear mixed models, individual factors that significantly explained visitation rates included the number of mammal species, the number of Big 5-species (ecological variables), the number of facilities provided (infrastructure) and average accommodation charges (affordability). Our analysis has important implications for the economic sustainability of PLCAs and more generally for understanding the relevance of spatial variation for analyses of cultural services.
- Full Text:
- Date Issued: 2017
- Authors: Baum, Julia , Cumming, Graeme S , de Vos, Alta
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/416481 , vital:71352 , xlink:href="https://doi.org/10.1016/j.ecolecon.2017.05.005"
- Description: Protected areas connect socio-economic and ecological systems through their provision of ecosystem goods and services. Analysis of ecosystem services allows the expression of ecological benefits in economic terms. However, cultural services, such as recreation opportunities, have proved difficult to quantify. An important challenge for the analysis of cultural services is to understand the geography of service provision in relation to both human and ecological system elements. We used data on visitation rates and measures of context, content, connectivity, and location for 64 private land conservation areas (PLCAs) to better understand geographic influences on cultural service provision. Visitation to PLCAs was influenced by a combination of ecological and socio-economic drivers. Variance partitioning analysis showed that ecology explained the largest proportion of overall variation in visitation rates (26%), followed by location (22%). In tests using generalized linear mixed models, individual factors that significantly explained visitation rates included the number of mammal species, the number of Big 5-species (ecological variables), the number of facilities provided (infrastructure) and average accommodation charges (affordability). Our analysis has important implications for the economic sustainability of PLCAs and more generally for understanding the relevance of spatial variation for analyses of cultural services.
- Full Text:
- Date Issued: 2017
Voices of the hungry: A qualitative measure of household food access and food insecurity in South Africa
- Chakona, Gamuchirai, Shackleton, Charlie M
- Authors: Chakona, Gamuchirai , Shackleton, Charlie M
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/398443 , vital:69412 , xlink:href="https://doi.org/10.1186/s40066-017-0149-x"
- Description: South Africa is rated a food secure nation, but large numbers of households within the country have inadequate access to nutrient-rich diverse foods. The study sought to investigate households’ physical and economic access and availability of food, in relation to local context which influences households’ access to and ability to grow food which may affect the dietary quality. We sought to understand self-reported healthy diets, food insecurity from the perspective of people who experienced it, barriers to household food security and perceptions and feelings on food access as well as strategies households use to cope with food shortages and their perceptions on improving household food security.
- Full Text:
- Date Issued: 2017
- Authors: Chakona, Gamuchirai , Shackleton, Charlie M
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/398443 , vital:69412 , xlink:href="https://doi.org/10.1186/s40066-017-0149-x"
- Description: South Africa is rated a food secure nation, but large numbers of households within the country have inadequate access to nutrient-rich diverse foods. The study sought to investigate households’ physical and economic access and availability of food, in relation to local context which influences households’ access to and ability to grow food which may affect the dietary quality. We sought to understand self-reported healthy diets, food insecurity from the perspective of people who experienced it, barriers to household food security and perceptions and feelings on food access as well as strategies households use to cope with food shortages and their perceptions on improving household food security.
- Full Text:
- Date Issued: 2017
West African arthropods hold promise as biological control agents for an invasive tree in the Pacific Islands
- Paterson, Iain D, Paynter, Quentin, Neser, Stefan, Akpabey, FJ, Compton, Stephen G
- Authors: Paterson, Iain D , Paynter, Quentin , Neser, Stefan , Akpabey, FJ , Compton, Stephen G
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/407119 , vital:70338 , xlink:href="https://hdl.handle.net/10520/EJC-639c91613"
- Description: African tulip tree, Spathodea campanulata Beauv. (Bignoniaceae), is a large tree of secondary forests, forest edges and savannas that is indigenous to Central and West Africa (Bidgood 1994). It has been widely utilised as an ornamental plant due to its beautiful flowers, fast growth and relative ease of cultivation, as a shade tree in parks and coffee plantations, and as a living fencepost (Francis 1990). Naturalisation has often followed cultivation of the plant, which is now established outside of the native range in Africa (Hedberg et al. 2006), the Caribbean (Francis 1990; Labrada and Medina 2009) and many Pacific islands (Meyer 2004), including Hawaii, Papua New Guinea, Fiji, Samoa, Tonga,Vanuatu and Tahiti (Lowe et al. 2000; Dovey et al. 2004; Labrada and Medina 2009). On some of these islands it has become a destructive weed, invading indigenous forests and having a severe impact on agricultural production (Labrada and Medina 2009; Larrue et al. 2014). This has resulted in African tulip tree being recognised as one of the 100 worst alien invasive species worldwide, along with only 30 other terrestrial plants (Lowe et al. 2000).
- Full Text:
- Date Issued: 2017
- Authors: Paterson, Iain D , Paynter, Quentin , Neser, Stefan , Akpabey, FJ , Compton, Stephen G
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/407119 , vital:70338 , xlink:href="https://hdl.handle.net/10520/EJC-639c91613"
- Description: African tulip tree, Spathodea campanulata Beauv. (Bignoniaceae), is a large tree of secondary forests, forest edges and savannas that is indigenous to Central and West Africa (Bidgood 1994). It has been widely utilised as an ornamental plant due to its beautiful flowers, fast growth and relative ease of cultivation, as a shade tree in parks and coffee plantations, and as a living fencepost (Francis 1990). Naturalisation has often followed cultivation of the plant, which is now established outside of the native range in Africa (Hedberg et al. 2006), the Caribbean (Francis 1990; Labrada and Medina 2009) and many Pacific islands (Meyer 2004), including Hawaii, Papua New Guinea, Fiji, Samoa, Tonga,Vanuatu and Tahiti (Lowe et al. 2000; Dovey et al. 2004; Labrada and Medina 2009). On some of these islands it has become a destructive weed, invading indigenous forests and having a severe impact on agricultural production (Labrada and Medina 2009; Larrue et al. 2014). This has resulted in African tulip tree being recognised as one of the 100 worst alien invasive species worldwide, along with only 30 other terrestrial plants (Lowe et al. 2000).
- Full Text:
- Date Issued: 2017
We’re talking about semantics here: Axiological condensation in the South African parliament
- Siebörger, Ian, Adendorff, Ralph D
- Authors: Siebörger, Ian , Adendorff, Ralph D
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/385389 , vital:68015 , xlink:href="https://doi.org/10.1075/fol.24.2.03sie"
- Description: This article describes how procedural knowledge is produced in a meeting of the South African parliament’s Portfolio Committee on Transport, using concepts from Systemic Functional Linguistics (SFL) and Legitimation Code Theory (LCT). Members of this committee argue over whether or not to amend a draft committee report and in the process co-construct procedural norms for future committee meetings. Participants on both sides of the argument use axiological condensation, in which actions and ideas are associated with each other and charged with a particular moral or affective value ( Maton 2014 : 130) to portray their version of the procedure to be followed as morally superior to that of their opponents. They also use axiological rarefaction ( Maton 2014 : 130) to reinforce their positions by making apparent concessions to those on the other side of the argument. This is revealed through an analysis of the coupling of ideation and Appraisal ( Martin 2000 : 161) in the logogenetic unfolding of members’ talk, combined with elements of Interactional Sociolinguistics ( Gumperz 1982 ). The analysis suggests that axiological condensation and rarefaction in this meeting reflect competing visions of what it means to be ‘pro-democracy’ in post-apartheid South Africa.
- Full Text:
- Date Issued: 2017
- Authors: Siebörger, Ian , Adendorff, Ralph D
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/385389 , vital:68015 , xlink:href="https://doi.org/10.1075/fol.24.2.03sie"
- Description: This article describes how procedural knowledge is produced in a meeting of the South African parliament’s Portfolio Committee on Transport, using concepts from Systemic Functional Linguistics (SFL) and Legitimation Code Theory (LCT). Members of this committee argue over whether or not to amend a draft committee report and in the process co-construct procedural norms for future committee meetings. Participants on both sides of the argument use axiological condensation, in which actions and ideas are associated with each other and charged with a particular moral or affective value ( Maton 2014 : 130) to portray their version of the procedure to be followed as morally superior to that of their opponents. They also use axiological rarefaction ( Maton 2014 : 130) to reinforce their positions by making apparent concessions to those on the other side of the argument. This is revealed through an analysis of the coupling of ideation and Appraisal ( Martin 2000 : 161) in the logogenetic unfolding of members’ talk, combined with elements of Interactional Sociolinguistics ( Gumperz 1982 ). The analysis suggests that axiological condensation and rarefaction in this meeting reflect competing visions of what it means to be ‘pro-democracy’ in post-apartheid South Africa.
- Full Text:
- Date Issued: 2017