Group 12 metal chalcogenides as single source molecular precursors for the preparation of metal sulfide nanoparticles
- Osuntokun, Jejenija https://orcid.org/0000-0003-0886-2732
- Authors: Osuntokun, Jejenija https://orcid.org/0000-0003-0886-2732
- Date: 2013-01
- Subjects: Ligands , Chalcogenides , Chemistry, Inorganic
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27428 , vital:67295
- Description: Twelve Zn(II), Cd(II) and Hg(II) complexes of mixed ligands: alkyl thiourea, 1-ethoxylcarbonyl-1-cyanoethylene-2,2-dithiolate and tetramethylthiuram disulfide were synthesized by the reaction between the ligands and the respective metal salts. The compounds were characterized by elemental analysis, infrared (IR), 1H- and 13C-NMR spectroscopy. Four coordinate geometries were proposed for the compounds based on elemental and spectroscopic analyses. The metal complexes were at best sparingly soluble in polar coordinating solvents such as DMSO and DMF and insoluble in most organic solvents. This makes it practically impossible to grow single crystals suitable for X-ray crystallographic analysis and also resulted in extremely poor 13C-NMR spectra for some of the complexes. Thermogravimetric analysis on some of the complexes showed that they decomposed to their respective metal sulfides and thus suitable as single molecular precursors for the preparation of metal sulfide nanoparticles. Nine of the complexes with good yield were thermolysed and used as single source precursors to synthesized hexadexylamine capped metal sulfide nanoparticles. The optical and structural properties of the nanoparticles were studied using UV-Visible, photoluminescence (PL), scanning electron microscopy (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (XRD) and energy dispersive spectroscopy (EDX). The absorption and emission spectra of the nanoparticles show quantum confinement. The SEM showed the morphology of the particles as nearly spherical, the EDX spectra revealed peaks corresponding to respective metal and sulfur with traces of contaminants being phosphorus from tri-n-octylphosphine (TOP). , Thesis (MSc) -- Faculty of Science and Agriculture, 2013
- Full Text:
- Authors: Osuntokun, Jejenija https://orcid.org/0000-0003-0886-2732
- Date: 2013-01
- Subjects: Ligands , Chalcogenides , Chemistry, Inorganic
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27428 , vital:67295
- Description: Twelve Zn(II), Cd(II) and Hg(II) complexes of mixed ligands: alkyl thiourea, 1-ethoxylcarbonyl-1-cyanoethylene-2,2-dithiolate and tetramethylthiuram disulfide were synthesized by the reaction between the ligands and the respective metal salts. The compounds were characterized by elemental analysis, infrared (IR), 1H- and 13C-NMR spectroscopy. Four coordinate geometries were proposed for the compounds based on elemental and spectroscopic analyses. The metal complexes were at best sparingly soluble in polar coordinating solvents such as DMSO and DMF and insoluble in most organic solvents. This makes it practically impossible to grow single crystals suitable for X-ray crystallographic analysis and also resulted in extremely poor 13C-NMR spectra for some of the complexes. Thermogravimetric analysis on some of the complexes showed that they decomposed to their respective metal sulfides and thus suitable as single molecular precursors for the preparation of metal sulfide nanoparticles. Nine of the complexes with good yield were thermolysed and used as single source precursors to synthesized hexadexylamine capped metal sulfide nanoparticles. The optical and structural properties of the nanoparticles were studied using UV-Visible, photoluminescence (PL), scanning electron microscopy (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (XRD) and energy dispersive spectroscopy (EDX). The absorption and emission spectra of the nanoparticles show quantum confinement. The SEM showed the morphology of the particles as nearly spherical, the EDX spectra revealed peaks corresponding to respective metal and sulfur with traces of contaminants being phosphorus from tri-n-octylphosphine (TOP). , Thesis (MSc) -- Faculty of Science and Agriculture, 2013
- Full Text:
Integrating legacy applications into service oriented architecture middleware
- Makamba, Makaziwe https://orcid.org/0000-0001-6998-4480
- Authors: Makamba, Makaziwe https://orcid.org/0000-0001-6998-4480
- Date: 2012-12
- Subjects: Service-oriented architecture (Computer science) , Computer architecture
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/24294 , vital:62599
- Description: Information and Communication Technology (ICT) is a dynamic approach that is widely recognized as an innovative and powerful tool for socio-economic development, it is a key catalyst for the emergence of knowledge economy. ICT have been used to develop applications, promote transparency and efficiency in multiple services such e-Learning, e-Government, e-Health and e-Judiciary especially for Marginalized Rural Areas (MRAs). The ICT approach is designed to bridge the digital divide. This approach has been widely deployed in many programs and it has led to the development of a new field which is Information and Communication Technology for Development (ICT4D). Within the context of ICT4D there are arrays of e-services that have been deployed to improve the impoverished communities. Some of these applications have failed to bring the changes that were designed to bring in the community due to the use of old architectures. There is therefore a need to develop a system that will integrate legacy applications into contemporary architectures. To solve the problem of the legacy applications we have developed TeleWeaver Service Oriented Architecture (SOA) middleware into which we integrate an e-Commerce and e-Learning applications into SOA middleware. For this integration system there are specific technologies that were used to integrate legacy applications into SOA middleware: RESTful web services using the slim API, SOAP via Nu-SOAP technologies were used to integrate these legacy applications. Specific methodologies were used to achieve the objectives of this research. The literature review, brainstorming, interviews and development of the system are some of the methods that were used to achieve the objectives of this study. The research methodology is mainly through experiments and to study TeleWeaver SOA middleware architecture. Interviews were conducted to analyze and understand the community needs, since the application discussed in this thesis is tested and implemented for a rural community. The community is called Dwesa, and falls under the ICT project within the Siyakhula Living Lab (SLL). A basic prototyping and Unified Modeling Language (UML) was created to design the system. This thesis presents the design and implementation of a system that integrates legacy applications into an SOA middleware that brings flexibility and effectiveness to these ICT e-services. The research focuses on integrating legacy applications into Service Oriented Architecture (SOA) middleware. It seeks to bring flexibility to e-services that are developed for MRAs. The use of SOA architecture that supports re-usability and interoperability of application provides effectiveness to the e-services. The novelty of the system is in its flexibility, usability and sustainability. SOA is an approach that provides a separation between the interface of the service and its underlying implementation. One of the achievements of the integration project is its ability to connect to SOA middleware. This increases the effectiveness of these e-services. The usability and performance evaluations are conducted to test and evaluate the system within the SLL on the TeleWeaver platform. , Thesis (MSc) -- Faculty of Science and Agriculture, 2012
- Full Text:
- Authors: Makamba, Makaziwe https://orcid.org/0000-0001-6998-4480
- Date: 2012-12
- Subjects: Service-oriented architecture (Computer science) , Computer architecture
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/24294 , vital:62599
- Description: Information and Communication Technology (ICT) is a dynamic approach that is widely recognized as an innovative and powerful tool for socio-economic development, it is a key catalyst for the emergence of knowledge economy. ICT have been used to develop applications, promote transparency and efficiency in multiple services such e-Learning, e-Government, e-Health and e-Judiciary especially for Marginalized Rural Areas (MRAs). The ICT approach is designed to bridge the digital divide. This approach has been widely deployed in many programs and it has led to the development of a new field which is Information and Communication Technology for Development (ICT4D). Within the context of ICT4D there are arrays of e-services that have been deployed to improve the impoverished communities. Some of these applications have failed to bring the changes that were designed to bring in the community due to the use of old architectures. There is therefore a need to develop a system that will integrate legacy applications into contemporary architectures. To solve the problem of the legacy applications we have developed TeleWeaver Service Oriented Architecture (SOA) middleware into which we integrate an e-Commerce and e-Learning applications into SOA middleware. For this integration system there are specific technologies that were used to integrate legacy applications into SOA middleware: RESTful web services using the slim API, SOAP via Nu-SOAP technologies were used to integrate these legacy applications. Specific methodologies were used to achieve the objectives of this research. The literature review, brainstorming, interviews and development of the system are some of the methods that were used to achieve the objectives of this study. The research methodology is mainly through experiments and to study TeleWeaver SOA middleware architecture. Interviews were conducted to analyze and understand the community needs, since the application discussed in this thesis is tested and implemented for a rural community. The community is called Dwesa, and falls under the ICT project within the Siyakhula Living Lab (SLL). A basic prototyping and Unified Modeling Language (UML) was created to design the system. This thesis presents the design and implementation of a system that integrates legacy applications into an SOA middleware that brings flexibility and effectiveness to these ICT e-services. The research focuses on integrating legacy applications into Service Oriented Architecture (SOA) middleware. It seeks to bring flexibility to e-services that are developed for MRAs. The use of SOA architecture that supports re-usability and interoperability of application provides effectiveness to the e-services. The novelty of the system is in its flexibility, usability and sustainability. SOA is an approach that provides a separation between the interface of the service and its underlying implementation. One of the achievements of the integration project is its ability to connect to SOA middleware. This increases the effectiveness of these e-services. The usability and performance evaluations are conducted to test and evaluate the system within the SLL on the TeleWeaver platform. , Thesis (MSc) -- Faculty of Science and Agriculture, 2012
- Full Text:
Preparation and characterisation of nanocomposite biodegradable films of hake fish gelatine and Na-montmorillonite
- Authors: Mutize, Innocent
- Date: 2012-12
- Subjects: Nanocomposites (Materials) , Food -- Packaging
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/24261 , vital:62595
- Description: Hake fish (Merluccius paradoxus) based films were prepared using gelatine extracted from hake fish bones and skins. They were characterized using FTIR, TGA and XRD. Polyethylene glycol and distilled water were used as plasticizer and solvent respectively. Montmorillonite clay was also added to the film matrix at different concentration (1-13percent gelatine weight) to improve the films‟ functional properties. Fourier Transform Infrared (FTIR), Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis (SDS-PAGE) and Ultra Violet-Visible (UV-Vis) spectroscopy analysis were used to characterise gelatine extracted from hake fish bones and skins. The extraction time and temperature were varied between 30 mins to 120 mins and 45°C to 75°C respectively. The yields of the gelatines extracted at the stated conditions were calculated from the hydroxyproline content giving values of 30 to 39percent, 43 to 55percent and 50 to 57percent for extraction at 45°C, 60°C and 75°C respectively. The effect of polyethylene glycol content on the mechanical and barrier properties of hake fish gelatine films was also investigated. The addition of polyethylene glycol to the film solution increased the water vapour permeability from 0.0321 ± 0.0011 ng.m/m2.s.Pa to 0.0993 ± 0.0007 ng.m/m2.s.Pa between 5 and 35percent polyethylene glycol content and decreased tensile strength from 41.92 ± 2.17 MPa to 29.93 ± 0.17 MPa. Sodium treated Montmorillonite was incorporated in the hake fish gelatine film solution in order to assess the effect of Montmorillonite clay on the film mechanical, barrier and thermal properties. Hake fish gelatine-montmorillonite composite films were successfully prepared and characterized. X-ray Diffraction (XRD) and Fourier Transform Infrared (FTIR) analysis indicated that the Montmorillonite clay in the film matrices was in an exfoliated state. Water vapour permeability was reduced from 0.0312 ± 0.0016 ng.m/m2.s.Pa to 0.0081 ± 0.0001ng.m/m2.s.Pa and tensile strength improved from 29.93 ± 0.17MPa to 76.78 ± 1.13 MPa. , Thesis (MSc) -- Faculty of Science and Agriculture, 2012
- Full Text:
- Authors: Mutize, Innocent
- Date: 2012-12
- Subjects: Nanocomposites (Materials) , Food -- Packaging
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/24261 , vital:62595
- Description: Hake fish (Merluccius paradoxus) based films were prepared using gelatine extracted from hake fish bones and skins. They were characterized using FTIR, TGA and XRD. Polyethylene glycol and distilled water were used as plasticizer and solvent respectively. Montmorillonite clay was also added to the film matrix at different concentration (1-13percent gelatine weight) to improve the films‟ functional properties. Fourier Transform Infrared (FTIR), Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis (SDS-PAGE) and Ultra Violet-Visible (UV-Vis) spectroscopy analysis were used to characterise gelatine extracted from hake fish bones and skins. The extraction time and temperature were varied between 30 mins to 120 mins and 45°C to 75°C respectively. The yields of the gelatines extracted at the stated conditions were calculated from the hydroxyproline content giving values of 30 to 39percent, 43 to 55percent and 50 to 57percent for extraction at 45°C, 60°C and 75°C respectively. The effect of polyethylene glycol content on the mechanical and barrier properties of hake fish gelatine films was also investigated. The addition of polyethylene glycol to the film solution increased the water vapour permeability from 0.0321 ± 0.0011 ng.m/m2.s.Pa to 0.0993 ± 0.0007 ng.m/m2.s.Pa between 5 and 35percent polyethylene glycol content and decreased tensile strength from 41.92 ± 2.17 MPa to 29.93 ± 0.17 MPa. Sodium treated Montmorillonite was incorporated in the hake fish gelatine film solution in order to assess the effect of Montmorillonite clay on the film mechanical, barrier and thermal properties. Hake fish gelatine-montmorillonite composite films were successfully prepared and characterized. X-ray Diffraction (XRD) and Fourier Transform Infrared (FTIR) analysis indicated that the Montmorillonite clay in the film matrices was in an exfoliated state. Water vapour permeability was reduced from 0.0312 ± 0.0016 ng.m/m2.s.Pa to 0.0081 ± 0.0001ng.m/m2.s.Pa and tensile strength improved from 29.93 ± 0.17MPa to 76.78 ± 1.13 MPa. , Thesis (MSc) -- Faculty of Science and Agriculture, 2012
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Market potential and profitability of improved maize open pollinated varieties in the Eastern Cape, South Africa
- Authors: Sibanda, Melusi
- Date: 2012-04
- Subjects: Hybrid corn , Crops -- Effect of stress on
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/24598 , vital:63211
- Description: Maize is one of the most important crops grown by smallholder farmers in Amatole and O.R. Tambo Districts of the Eastern Cape. For this study, there were 13 maize varieties that were evaluated extensively by on-farm trials in selected areas under dry land and irrigated conditions. Nine were newly introduced and improved Open Pollinated Varieties (OPVs), while four were locally grown varieties. Among the locally grown varieties, one was a hybrid-check, while the remaining three were improved OPVs. The objectives of this study were: to investigate the potential marketability of newly introduced maize OPVs, identify factors influencing farmers‟ demand of improved maize OPVs and assess their profitability when compared with hybrids. One hundred and thirty seven sample households were interviewed using a structured questionnaire. The data was analyzed using descriptive statistics (frequency, percentages), gross margins and regression analyses. Data for computing gross margins was taken from the on-farm trials. Results showed that the actual production of improved maize OPVs constituted 0percent in Zanyokwe Irrigation Scheme (ZIS) and 20percent of the farmers in the O.R. Tambo District. At Silwindlala Women‟s Project (SWP), the improved maize OPV (Sahara) was grown. The majority of the farmers in the study areas were growing competitor varieties (hybrids and/or in conjunction with landraces). Results show that, there is potential market for improved maize OPVs in the Eastern Cape. The majority of the farmers, 87percent and 92percent in Amatole (SWP and ZIS) and O.R. Tambo Districts respectively, indicated that they were willing to adopt the newly introduced maize OPVs. Results showed that the hybrid PAN 6479 variety in general performed better than improved maize OPVs whereas in some areas, the improved maize OPVs had better gross margins and gross profit margins than the hybrid variety. The indicated genotypes did not show specific adaptation to selected environments. The demand model that employed a multiple regression model was used and data was analyzed using Statistical Package for the Social Science (SPSS) computer software. Results of the multiple regression model showed that household socio-economic factors (extension contact, access to credit, availability of household income, proportion of land area under cultivation, proportion of land area under (hybrids and landrace) and perceptions on seed color) and an input market factor (availability of the improved maize OPV seeds on the local shops) were the most important factors influencing farmers' decisions to demanding the improved maize OPVs. Extension contact, access to credit, level of household income and proportion of land area under cultivation, positively influenced the demand for the improved maize OPVs whereas the unavailability of the improved maize OPV seeds on the local shops, proportion of land area under hybrids and landraces and perceptions on seed color negatively influenced the demand for the improved maize OPVs. , Thesis (MSc) -- Faculty of Science and Agriculture, 2012
- Full Text:
- Authors: Sibanda, Melusi
- Date: 2012-04
- Subjects: Hybrid corn , Crops -- Effect of stress on
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/24598 , vital:63211
- Description: Maize is one of the most important crops grown by smallholder farmers in Amatole and O.R. Tambo Districts of the Eastern Cape. For this study, there were 13 maize varieties that were evaluated extensively by on-farm trials in selected areas under dry land and irrigated conditions. Nine were newly introduced and improved Open Pollinated Varieties (OPVs), while four were locally grown varieties. Among the locally grown varieties, one was a hybrid-check, while the remaining three were improved OPVs. The objectives of this study were: to investigate the potential marketability of newly introduced maize OPVs, identify factors influencing farmers‟ demand of improved maize OPVs and assess their profitability when compared with hybrids. One hundred and thirty seven sample households were interviewed using a structured questionnaire. The data was analyzed using descriptive statistics (frequency, percentages), gross margins and regression analyses. Data for computing gross margins was taken from the on-farm trials. Results showed that the actual production of improved maize OPVs constituted 0percent in Zanyokwe Irrigation Scheme (ZIS) and 20percent of the farmers in the O.R. Tambo District. At Silwindlala Women‟s Project (SWP), the improved maize OPV (Sahara) was grown. The majority of the farmers in the study areas were growing competitor varieties (hybrids and/or in conjunction with landraces). Results show that, there is potential market for improved maize OPVs in the Eastern Cape. The majority of the farmers, 87percent and 92percent in Amatole (SWP and ZIS) and O.R. Tambo Districts respectively, indicated that they were willing to adopt the newly introduced maize OPVs. Results showed that the hybrid PAN 6479 variety in general performed better than improved maize OPVs whereas in some areas, the improved maize OPVs had better gross margins and gross profit margins than the hybrid variety. The indicated genotypes did not show specific adaptation to selected environments. The demand model that employed a multiple regression model was used and data was analyzed using Statistical Package for the Social Science (SPSS) computer software. Results of the multiple regression model showed that household socio-economic factors (extension contact, access to credit, availability of household income, proportion of land area under cultivation, proportion of land area under (hybrids and landrace) and perceptions on seed color) and an input market factor (availability of the improved maize OPV seeds on the local shops) were the most important factors influencing farmers' decisions to demanding the improved maize OPVs. Extension contact, access to credit, level of household income and proportion of land area under cultivation, positively influenced the demand for the improved maize OPVs whereas the unavailability of the improved maize OPV seeds on the local shops, proportion of land area under hybrids and landraces and perceptions on seed color negatively influenced the demand for the improved maize OPVs. , Thesis (MSc) -- Faculty of Science and Agriculture, 2012
- Full Text:
Synthesis, characterization and antibacterial studies of metal complexes of substituted thiourea
- Authors: Zulu, Happy Nonkululeko
- Date: 2012-03
- Subjects: Complex compounds , Halides , Ligands
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/24327 , vital:62636
- Description: Eighteen complexes Co(II), Cu(II), Zn(II), and Fe(III) with phenylthiourea, diethylthiourea, disopropylthiourea and dimethylthiourea were synthesized and characterized by elemental analysis, UV-Vis, FTIR, conductivity measurements. The complexes were formulated as either four coordinate for the metal(II) or six coordinate for Fe(III). The proposed formulations are consistent with the spectroscopic data for the complexes. The single crystal X-ray structure of the Zn(II) complex of phenylthiourea, Co(II) complex of diethylthiourea and Zn(II) complex of diisopropylthiourea are also reported. The X-ray crystal structures for these complexes revealed distorted tetrahedral geometry around the metal ions showed that the metal ions are coordinated to two molecules of the substituted thiourea through the sulphur atom and two either acetates or chlorides ions complete the four-coordinate geometry. The in vitro antibacterial activity of the complexes was studied against six bacterial strains using disc diffusion and broth micro-dilution methods. The complexes showed selective antibacterial activity. , Thesis (MSc) -- Faculty of Science and Agriculture, 2012
- Full Text:
- Authors: Zulu, Happy Nonkululeko
- Date: 2012-03
- Subjects: Complex compounds , Halides , Ligands
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/24327 , vital:62636
- Description: Eighteen complexes Co(II), Cu(II), Zn(II), and Fe(III) with phenylthiourea, diethylthiourea, disopropylthiourea and dimethylthiourea were synthesized and characterized by elemental analysis, UV-Vis, FTIR, conductivity measurements. The complexes were formulated as either four coordinate for the metal(II) or six coordinate for Fe(III). The proposed formulations are consistent with the spectroscopic data for the complexes. The single crystal X-ray structure of the Zn(II) complex of phenylthiourea, Co(II) complex of diethylthiourea and Zn(II) complex of diisopropylthiourea are also reported. The X-ray crystal structures for these complexes revealed distorted tetrahedral geometry around the metal ions showed that the metal ions are coordinated to two molecules of the substituted thiourea through the sulphur atom and two either acetates or chlorides ions complete the four-coordinate geometry. The in vitro antibacterial activity of the complexes was studied against six bacterial strains using disc diffusion and broth micro-dilution methods. The complexes showed selective antibacterial activity. , Thesis (MSc) -- Faculty of Science and Agriculture, 2012
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Effect of fluoroquinolones antibiotics on vancomycin and oxacillin resistant staphylococcus species in Eastern Cape Province
- Authors: Soyege, Oludotun
- Date: 2012
- Subjects: Staphylococcus aureus , Quinolone antibacterial agents , Fluoroquinolones
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/25349 , vital:64212
- Description: This study shows the susceptibility profile of some Staphylococcus species isolated from commensal Staphylococci in Nkonkobe municipality, South Africa. A total number of 120 Staphylococcal isolates were screened for their susceptibilities to various classes of antibiotics such as Aminoglycoside (Gentamycin), Aminoglycoside (Kanamycin), Macrolide (Erythromycin), Tetracycline (Minocycline), Anti-tuberculous (Rifampicin), Lincosamides (Clindamycin), Cephalosporin and Fluoroquinolones in general. During the study, 32 (26percent) the test organisms were susceptible to both methicillin and vancomycin, while 12 (10percent) had co-resistance to the antibiotics. Furthermore, Gentamycin (an Aminoglycoside) had a relatively high potency against the isolates with 107 (89.17percent) of the bacteria being susceptible to it, while 10 (8.33percent) were resistant. On the other hand, Erythromycin (a Macrolide) was active against 72 (60percent) of the isolates, while 5 (4.17percent) and 74 (61.67percent) of the isolates yielded intermediate and resistant responses respectively. In addition , 51 (42.5percent) of the isolates were susceptible to rifampicin, while 1 (0.83percent) and 17 (14.17percent) were intermediate and resistant respectively. Ten percent of the isolates screened for their antibiotic susceptibility pattern in this study were positive for mecA gene among the vancomycin-oxacillin resistant strains while van gene was not detected in any of the isolates. This shows how the synergy of both vancomycin and oxacillin contribute to some resistance nature of Staphylococci. In order to overcome this resistance attributes of Staphylococci, to the commonly used antibiotics as discussed under this context, various types of fluoroquinolones were tested. The result shows that less than 10percent of the isolates were generally resistant to the fluoroquinolones except against Nalidix acid to which all the isolates were resistant. Other antibiotics had relatively higher resistance patterns as observed for minocycline (39.51percent), clindamycin (12.75percent), gentamycin (12.31percent) and vancomycin (12.3percent). The new generation fluoroquinolones including Gatifloxacin, Levofloxacin, Moxifloxacin and Ciprofloxacin to which less than 5percent of the bacteria are resistant gives some clinical advantage over the Methicillin and Vancomycin resistant strains. About 31percent of the isolates had multiple antibiotic resistance index of ≥1 and suggests animals in the community as potential reservoirs of antibiotic resistance determinants in the environment. Data obtained in this study is of epidemiological importance and valuable for disease control. , Thesis (MSc) -- Faculty of Science and Agriculture, 2012
- Full Text:
- Authors: Soyege, Oludotun
- Date: 2012
- Subjects: Staphylococcus aureus , Quinolone antibacterial agents , Fluoroquinolones
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/25349 , vital:64212
- Description: This study shows the susceptibility profile of some Staphylococcus species isolated from commensal Staphylococci in Nkonkobe municipality, South Africa. A total number of 120 Staphylococcal isolates were screened for their susceptibilities to various classes of antibiotics such as Aminoglycoside (Gentamycin), Aminoglycoside (Kanamycin), Macrolide (Erythromycin), Tetracycline (Minocycline), Anti-tuberculous (Rifampicin), Lincosamides (Clindamycin), Cephalosporin and Fluoroquinolones in general. During the study, 32 (26percent) the test organisms were susceptible to both methicillin and vancomycin, while 12 (10percent) had co-resistance to the antibiotics. Furthermore, Gentamycin (an Aminoglycoside) had a relatively high potency against the isolates with 107 (89.17percent) of the bacteria being susceptible to it, while 10 (8.33percent) were resistant. On the other hand, Erythromycin (a Macrolide) was active against 72 (60percent) of the isolates, while 5 (4.17percent) and 74 (61.67percent) of the isolates yielded intermediate and resistant responses respectively. In addition , 51 (42.5percent) of the isolates were susceptible to rifampicin, while 1 (0.83percent) and 17 (14.17percent) were intermediate and resistant respectively. Ten percent of the isolates screened for their antibiotic susceptibility pattern in this study were positive for mecA gene among the vancomycin-oxacillin resistant strains while van gene was not detected in any of the isolates. This shows how the synergy of both vancomycin and oxacillin contribute to some resistance nature of Staphylococci. In order to overcome this resistance attributes of Staphylococci, to the commonly used antibiotics as discussed under this context, various types of fluoroquinolones were tested. The result shows that less than 10percent of the isolates were generally resistant to the fluoroquinolones except against Nalidix acid to which all the isolates were resistant. Other antibiotics had relatively higher resistance patterns as observed for minocycline (39.51percent), clindamycin (12.75percent), gentamycin (12.31percent) and vancomycin (12.3percent). The new generation fluoroquinolones including Gatifloxacin, Levofloxacin, Moxifloxacin and Ciprofloxacin to which less than 5percent of the bacteria are resistant gives some clinical advantage over the Methicillin and Vancomycin resistant strains. About 31percent of the isolates had multiple antibiotic resistance index of ≥1 and suggests animals in the community as potential reservoirs of antibiotic resistance determinants in the environment. Data obtained in this study is of epidemiological importance and valuable for disease control. , Thesis (MSc) -- Faculty of Science and Agriculture, 2012
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Molecular detection and drug susceptibility of Mycobacterium tuberculosis complex in raw milk from a major dairy farm in the Nkonkobe region, Eastern Cape Province, South Africa
- Silaigwana, Blessing https://orcid.org/0000-0002-3324-1607
- Authors: Silaigwana, Blessing https://orcid.org/0000-0002-3324-1607
- Date: 2012
- Subjects: Mycobacterium tuberculosis , Drug resistance in microorganisms , Tuberculosis -- Pathogenesis
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/24239 , vital:62543
- Description: Mycobacterium tuberculosis complex (MTBC) organisms are the causative agents of tuberculosis in humans as well as animals. The study aimed to use molecular techniques for detection and drug susceptibility testing of MTBC in raw milk from cattle at a dairy farm in the Nkonkobe region of South Africa. Two hundred samples (100mL each) were collected and processed using the modified Petroff’s method. DNA was isolated using the Zymo Research bacterial DNA kit and amplified using the Seeplex® MTB Nested ACE assay. Drug susceptibility testing was performed using the Genotype® MTBDRplus assay. MTBC DNA was detected in 11 (6percent) of the samples tested. Resistance to both rifampicin and isoniazid was detected in 90.9percent of the positive samples. The most frequent rpoB mutations detected were H526Y (90percent), H526D (80percent), S531L (60percent) and D516V (20percent). No mutation was detected in the katG gene. All isoniazid resistant samples harboured mutations in the inhA gene. The most frequent (100percent) mutation conferring low level isoniazid resistance was the T8A substitution. The inhA mutations C15T, A16G and T8C were equally represented with 60percent frequency. A high prevalence of multi-drug resistance was noted in the Nkonkobe region. Therefore, the results of this study have clinico-veterinary and epidemiological significance and calls for further studies and necessary actions to delineate the situation. , Thesis (MSc) -- Faculty of Science and Agriculture, 2012
- Full Text:
- Authors: Silaigwana, Blessing https://orcid.org/0000-0002-3324-1607
- Date: 2012
- Subjects: Mycobacterium tuberculosis , Drug resistance in microorganisms , Tuberculosis -- Pathogenesis
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/24239 , vital:62543
- Description: Mycobacterium tuberculosis complex (MTBC) organisms are the causative agents of tuberculosis in humans as well as animals. The study aimed to use molecular techniques for detection and drug susceptibility testing of MTBC in raw milk from cattle at a dairy farm in the Nkonkobe region of South Africa. Two hundred samples (100mL each) were collected and processed using the modified Petroff’s method. DNA was isolated using the Zymo Research bacterial DNA kit and amplified using the Seeplex® MTB Nested ACE assay. Drug susceptibility testing was performed using the Genotype® MTBDRplus assay. MTBC DNA was detected in 11 (6percent) of the samples tested. Resistance to both rifampicin and isoniazid was detected in 90.9percent of the positive samples. The most frequent rpoB mutations detected were H526Y (90percent), H526D (80percent), S531L (60percent) and D516V (20percent). No mutation was detected in the katG gene. All isoniazid resistant samples harboured mutations in the inhA gene. The most frequent (100percent) mutation conferring low level isoniazid resistance was the T8A substitution. The inhA mutations C15T, A16G and T8C were equally represented with 60percent frequency. A high prevalence of multi-drug resistance was noted in the Nkonkobe region. Therefore, the results of this study have clinico-veterinary and epidemiological significance and calls for further studies and necessary actions to delineate the situation. , Thesis (MSc) -- Faculty of Science and Agriculture, 2012
- Full Text:
Optimisation of expression of a rice (Oryza sativa L.cv Nipponbare) plant natriuretic peptide (OsPNP-B) and its functional characterisation
- Authors: Affun, Ogheneochuko Janet
- Date: 2012
- Subjects: Rice , Plant hormones , Water-electrolyte imbalances
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/24354 , vital:62644
- Description: Maintenance of water and solute homeostasis is a key requirement for living systems, and in vertebrates, homeostasis is in part achieved by natriuretic peptides (NP), a family of peptide hormones. A related family of peptide hormones have also been found in the plant kingdom. Plant natriuretic peptides (PNP) are a novel class of plant proteins with two closely related homologous genes (AtPNP-A and AtPNP-B) identified in the model plant Arabidopsis thaliana. AtPNP-A has been extensively studied and evidence obtained points to a role in plant water homeostasis. No research has been conducted on the function of PNP-B proteins. In this study, we focus on the bioinformatic analysis of the PNP-B gene in various plants, as well investigating whether PNP-B plays a role in water homeostasis in rice plants exposed to drought stress. Basic local alignment search tool (BLAST) queries of the ―The Gene Index‖, EST and available plant genome databases revealed the presence of the PNP-B mRNA in rice, oil seed rape, oak, leafy spurge, poplar, sugarcane, pepper, cotton, apple and maize. All the identified genome sequences contained a predicted intron/insert, which was not present in the related mRNA sequences. However, RT-PCR analysis revealed the presence of the 101 bp insert in the 976 bp amplified rice PNP-B (OsPNP-B) cDNA and therefore expression was optimized for the protein encoded by only the exon2 sequence as this contained the predicted active site region of PNP-B. OsPNP-B was shown to be translated to a protein of 14 kDa with a sequence similarity to AtPNP-B (54percent), AtPNP-A (37percent) and CjBAp12 (55percent), suggesting two possible functions for PNP-B viz water homeostasis and/or pathogenesis defence. To determine whether PNP-B is involved in water homeostasis, total protein extracted from 4 weeks old (4 leaves stage) rice plants subjected to drought treatment for a period of 24, 48, 72, 120, 168 and 240hrs were resolved by 17percent SDS-PAGE and analysed by western blot analysis. The PNP-B protein was found to be down-regulated during drought stress, implying that PNP-B may play a role in water homeostasis through the release of water from cells rather than the up-take of water as seen At-PNP-A. PNP-B could therefore also be involved in plant defence mechanisms to pathogens where plants induce desiccation of infected leaves, thereby ridding the plant of the relevant pathogen. , Thesis (MSc) -- Faculty of Science and Agriculture, 2012
- Full Text:
- Authors: Affun, Ogheneochuko Janet
- Date: 2012
- Subjects: Rice , Plant hormones , Water-electrolyte imbalances
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/24354 , vital:62644
- Description: Maintenance of water and solute homeostasis is a key requirement for living systems, and in vertebrates, homeostasis is in part achieved by natriuretic peptides (NP), a family of peptide hormones. A related family of peptide hormones have also been found in the plant kingdom. Plant natriuretic peptides (PNP) are a novel class of plant proteins with two closely related homologous genes (AtPNP-A and AtPNP-B) identified in the model plant Arabidopsis thaliana. AtPNP-A has been extensively studied and evidence obtained points to a role in plant water homeostasis. No research has been conducted on the function of PNP-B proteins. In this study, we focus on the bioinformatic analysis of the PNP-B gene in various plants, as well investigating whether PNP-B plays a role in water homeostasis in rice plants exposed to drought stress. Basic local alignment search tool (BLAST) queries of the ―The Gene Index‖, EST and available plant genome databases revealed the presence of the PNP-B mRNA in rice, oil seed rape, oak, leafy spurge, poplar, sugarcane, pepper, cotton, apple and maize. All the identified genome sequences contained a predicted intron/insert, which was not present in the related mRNA sequences. However, RT-PCR analysis revealed the presence of the 101 bp insert in the 976 bp amplified rice PNP-B (OsPNP-B) cDNA and therefore expression was optimized for the protein encoded by only the exon2 sequence as this contained the predicted active site region of PNP-B. OsPNP-B was shown to be translated to a protein of 14 kDa with a sequence similarity to AtPNP-B (54percent), AtPNP-A (37percent) and CjBAp12 (55percent), suggesting two possible functions for PNP-B viz water homeostasis and/or pathogenesis defence. To determine whether PNP-B is involved in water homeostasis, total protein extracted from 4 weeks old (4 leaves stage) rice plants subjected to drought treatment for a period of 24, 48, 72, 120, 168 and 240hrs were resolved by 17percent SDS-PAGE and analysed by western blot analysis. The PNP-B protein was found to be down-regulated during drought stress, implying that PNP-B may play a role in water homeostasis through the release of water from cells rather than the up-take of water as seen At-PNP-A. PNP-B could therefore also be involved in plant defence mechanisms to pathogens where plants induce desiccation of infected leaves, thereby ridding the plant of the relevant pathogen. , Thesis (MSc) -- Faculty of Science and Agriculture, 2012
- Full Text:
Experiences of community psychiatric nurses and guardians of discharged psychiatric patients on the effectiveness of community mental health services of the Zomba district in Malawi
- Authors: Kachingwe, Bertha Maggie
- Date: 2011-12
- Subjects: Psychiatric nursing , Community mental health services
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/24183 , vital:62440
- Description: Sturdy: Experiences of community psychiatric nurses and guardians of discharged psychiatric patients on the effectiveness of community mental health services of the Zomba District in Malawi. Purpose: The purpose of the study was to explore and describe the experiences of community psychiatric nurses and guardians of discharged psychiatric patients with regard to failure of Community Mental Health Services of the Zomba District, and make recommendations to improve community mental health services. Although such services exist, their effectiveness is unknown, either from the nurses’ point of view or from the consumers’ point of view. Method: A qualitative approach with phenomenological research design was used to answer the research question on the effectiveness of the services. This method was chosen because the researcher was committed to explore the lived in-depth experiences of the study participants. A purposive sampling method was used to select participants for the study, who were selected based on their knowledge of the phenomena. Data collection Instruments used were unstructured interviews, using face- to- face interaction. One broad, open-ended question was used to gather information from the participants. Data analysis was done using Atlas.ti software to help the researcher uncover complex phenomena hidden in the text. Findings: Participants from both groups overwhelmingly reported that community mental health services were not effective. Four categories and eleven themes of barriers impacting on ineffective services emerged from the nurses. For example; Inadequate service provision related to unavailability of resources (human, time and materials). Themes hindering effective services emerged from the guardians for example; Services not accessible related to inconsistent appointment dates, shortage of medications and poor economic status of participants. , Thesis (MCur) -- Faculty of Science and Agriculture, 2011
- Full Text:
- Authors: Kachingwe, Bertha Maggie
- Date: 2011-12
- Subjects: Psychiatric nursing , Community mental health services
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/24183 , vital:62440
- Description: Sturdy: Experiences of community psychiatric nurses and guardians of discharged psychiatric patients on the effectiveness of community mental health services of the Zomba District in Malawi. Purpose: The purpose of the study was to explore and describe the experiences of community psychiatric nurses and guardians of discharged psychiatric patients with regard to failure of Community Mental Health Services of the Zomba District, and make recommendations to improve community mental health services. Although such services exist, their effectiveness is unknown, either from the nurses’ point of view or from the consumers’ point of view. Method: A qualitative approach with phenomenological research design was used to answer the research question on the effectiveness of the services. This method was chosen because the researcher was committed to explore the lived in-depth experiences of the study participants. A purposive sampling method was used to select participants for the study, who were selected based on their knowledge of the phenomena. Data collection Instruments used were unstructured interviews, using face- to- face interaction. One broad, open-ended question was used to gather information from the participants. Data analysis was done using Atlas.ti software to help the researcher uncover complex phenomena hidden in the text. Findings: Participants from both groups overwhelmingly reported that community mental health services were not effective. Four categories and eleven themes of barriers impacting on ineffective services emerged from the nurses. For example; Inadequate service provision related to unavailability of resources (human, time and materials). Themes hindering effective services emerged from the guardians for example; Services not accessible related to inconsistent appointment dates, shortage of medications and poor economic status of participants. , Thesis (MCur) -- Faculty of Science and Agriculture, 2011
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Knowledge and attitudes of professional nurses towards HIV and AIDS patients at the Libode District Health Services in the Eastern Cape Province
- Authors: Gedu, Grace Nontuthuzelo
- Date: 2011-12
- Subjects: Rural health services , AIDS (Disease)
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/24610 , vital:63213
- Description: This study was conducted at the Libode District Health Services amongst professional nurses who render services to HIV and AIDS patients. Generally, caring for HIV positive patients, nurses need to be knowledgeable about the transmission of the HIV virus, in order to render quality care to the patients. They also need to be sensitive and to demonstrate positive attitudes towards the patients. It was unknown whether the professional nurses at the Libode District Health Services are knowledgeable or not regarding HIV and AIDS. Their attitudes towards the HIV positive patients, were also unknown. Not knowing the knowledge and attitude of professional nurses regarding HIV and AIDS has the potential to compromise the quality of nursing care rendered to the patients. The purpose of the study was to explore and describe the level of knowledge of professional nurses regarding HIV and AIDS well as their attitudes towards the HIV-positive patients so as to make recommendations for quality patient care based on the results. A quantitative explorative descriptive research design was used to examine the level of knowledge about HIV and AIDS as well as the attitudes of professional nurses to HIV and AIDS patients. The target populations were the 218 professional nurses working at the Libode District Health services who had nursed HIV positive patients. A simple random sampling method was used to select a sample of 120 participants. A structured self-administered questionnaire was used to obtain data. The questionnaire consisted of a section on the demographic profile of the participants, and two other sections for responses on knowledge and attitudes. Data were analyzed using Statistical Package for the Social Sciences (SPSS) version 17.0 software for consistency of the twenty (20) items in the questionnaire. Findings showed that nurses of Libode District Health Services had an approximately fair amount of knowledge. The majority (79percent) of participants scored above the cut-off point of 24. Twenty one percent (21percent) scored below 24. On attitude, the majority (76percent) had scored below the cut-off point of 36. Recommendations were that professional nurses of Libode District Health Services, need to be exposed to ongoing training on HIV and AIDS to increase their knowledge about HIV and AIDS and to ensure that they demonstrate positive attitudes towards HIV and AIDS patients. , Thesis (MSc) -- Faculty of Science and Agriculture, 2011
- Full Text:
- Authors: Gedu, Grace Nontuthuzelo
- Date: 2011-12
- Subjects: Rural health services , AIDS (Disease)
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/24610 , vital:63213
- Description: This study was conducted at the Libode District Health Services amongst professional nurses who render services to HIV and AIDS patients. Generally, caring for HIV positive patients, nurses need to be knowledgeable about the transmission of the HIV virus, in order to render quality care to the patients. They also need to be sensitive and to demonstrate positive attitudes towards the patients. It was unknown whether the professional nurses at the Libode District Health Services are knowledgeable or not regarding HIV and AIDS. Their attitudes towards the HIV positive patients, were also unknown. Not knowing the knowledge and attitude of professional nurses regarding HIV and AIDS has the potential to compromise the quality of nursing care rendered to the patients. The purpose of the study was to explore and describe the level of knowledge of professional nurses regarding HIV and AIDS well as their attitudes towards the HIV-positive patients so as to make recommendations for quality patient care based on the results. A quantitative explorative descriptive research design was used to examine the level of knowledge about HIV and AIDS as well as the attitudes of professional nurses to HIV and AIDS patients. The target populations were the 218 professional nurses working at the Libode District Health services who had nursed HIV positive patients. A simple random sampling method was used to select a sample of 120 participants. A structured self-administered questionnaire was used to obtain data. The questionnaire consisted of a section on the demographic profile of the participants, and two other sections for responses on knowledge and attitudes. Data were analyzed using Statistical Package for the Social Sciences (SPSS) version 17.0 software for consistency of the twenty (20) items in the questionnaire. Findings showed that nurses of Libode District Health Services had an approximately fair amount of knowledge. The majority (79percent) of participants scored above the cut-off point of 24. Twenty one percent (21percent) scored below 24. On attitude, the majority (76percent) had scored below the cut-off point of 36. Recommendations were that professional nurses of Libode District Health Services, need to be exposed to ongoing training on HIV and AIDS to increase their knowledge about HIV and AIDS and to ensure that they demonstrate positive attitudes towards HIV and AIDS patients. , Thesis (MSc) -- Faculty of Science and Agriculture, 2011
- Full Text:
An evaluation of stress tolerant open pollinated maize varieties in selected environments of the Eastern Cape Province, South Africa
- Chimonyo, Vimbayi G P https://orcid.org/0000-0001-9912-9848
- Authors: Chimonyo, Vimbayi G P https://orcid.org/0000-0001-9912-9848
- Date: 2011-11
- Subjects: Crops -- Effect of stress on
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/24487 , vital:63045
- Description: The use of farmer acceptable, stress tolerant open pollinated maize varieties (OPVs) could be a strategy to help increase maize productivity for resource-poor farmers in the Eastern Cape (EC) Province. The current study investigated the following: a) participatory selection of newly introduced stress tolerant maize OPVs; b) characteristics of maize producing farmers, their production constraints and criteria for variety selections; c) multi-environment yield trials in which genotype and environment interactions (GEI) were investigated, and d) morphological diversity of newly introduced maize varieties. Nine newly introduced maize OPVs were evaluated in this study. These varieties were: ZM 305, ZM 423 ZM 501, ZM 525, Obatanpa, ZM 621, ZM 627, which were from the International Maize and Wheat Improvement Centre (CIMMYT), BR 993, and Comp 4 which from where the International Institute of Tropical Agriculture (IITA). Check varieties, Pan 6479 (a hybrid) and three locally grown OPVs (Okavango, Afric 1 and Nelson‘s Choice) were also included. Participatory variety selection (PVS) was conducted during the 2009/10 summer season to evaluate farmer acceptance of these newly introduced OPVs. The most preferred varieties farmers were Okavango, ZM 305 and ZM 501, and these varieties were not significantly different from the highest yielding variety within each site. Therefore, varieties like ZM 305 and ZM 501 could easily be adopted by farmers, and their use could result in yield improvements. To gather information on farmer characteristics, and perceptions on maize production constraints and maize selection criteria, focus group discussions and household surveys were conducted during the 2009/2010 and 2010/2011 seasons, respectively. Results indicated that, elderly farmers dominated the farming communities. Maize production was generally low, with 98percent of the farmers obtaining less than 1.6 t/ha. The most important constraints affecting maize production were extreme weather events (floods and drought), pests and diseases, and poor access to credit. The most preferred traits that made up farmer selection criteria were ear traits such as taste, long cobs, and big kernels. Other traits, such as, prolificacy, early maturity, retainability of seed and dark leaves, were village specific. Yield trials, assessing genotype and environment interactions, were conducted in eight sites during the 2009/10 and 2010/11 seasons. The genotypes exhibited non-significant crossover and non-crossover GEI over the environments. Okavango, the most stable variety, was generally low yielding (4.28 t/ha) than other stable varieties such as ZM 305, ZM 501, ZM 621 and ZM 423. The later varieties had significantly (p<0.05) higher yields of between 4.46 t/ha and 4.97 t/ha. The highest yielding varieties, Pan 6479 (5.29 t/ha) and ZM 525 (4.87 t/ha), showed specific adaptations to high potential environments, while BR 993 (4.07 t/ha) and Afric 1 (4.24 t/ha) were low yielding, unstable and specifically adapted to low potential environments. New varieties, therefore, exhibited both specific and wide adaptation. Qualitative and quantitative traits were evaluated to establish the morphological diversity of the 13 varieties. Ear height, plant height, days to 50percent anthesis and grain yield contributed the most to variety diversity. Cluster Analysis discriminated varieties into four main clusters. The first cluster consisted of four CIMMYT varieties that were short in height and early maturing (ZM 305, ZM 423, ZM 501 and ZM 525), while hybrid Pan 6479 was placed into cluster two. Nelson‘s Choice and Okavango were grouped into the third cluster, while tall and late maturing varieties, ZM 621, ZM 627, Obatanpa, BR 993, Comp 4 and Afric 1, were placed in the fourth cluster. The segregation of the newly introduced varieties into two distinct groups shows that these varieties can be recommended into more than on cropping system and agro-ecology. Differences in village agro-ecologies resulted in farmers selecting varieties differently. This diversity in agro-ecology also brought about variations on farmer perceptions in selection criteria and production constraints. Most of the new varieties were observed to be superior in yield performance when compared to local check OPVs, exhibiting either wide or specific adaptation. The study also demonstrated that, the study of morphological diversity can be used to suggest varieties to different environmental potentials and cropping systems. Multi-evaluation trials were able to give an insight on variety preferences and performance. These new varieties should, therefore, be introduced to selected farmers living in their respective environments on the basis of results obtained. However, varieties still need to be evaluated under farmer-managed conditions to determine whether they actually bring about yield improvement when compared with current varieties being used. , Thesis (MSc) -- Faculty of Science and Agriculture, 2011
- Full Text:
- Authors: Chimonyo, Vimbayi G P https://orcid.org/0000-0001-9912-9848
- Date: 2011-11
- Subjects: Crops -- Effect of stress on
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/24487 , vital:63045
- Description: The use of farmer acceptable, stress tolerant open pollinated maize varieties (OPVs) could be a strategy to help increase maize productivity for resource-poor farmers in the Eastern Cape (EC) Province. The current study investigated the following: a) participatory selection of newly introduced stress tolerant maize OPVs; b) characteristics of maize producing farmers, their production constraints and criteria for variety selections; c) multi-environment yield trials in which genotype and environment interactions (GEI) were investigated, and d) morphological diversity of newly introduced maize varieties. Nine newly introduced maize OPVs were evaluated in this study. These varieties were: ZM 305, ZM 423 ZM 501, ZM 525, Obatanpa, ZM 621, ZM 627, which were from the International Maize and Wheat Improvement Centre (CIMMYT), BR 993, and Comp 4 which from where the International Institute of Tropical Agriculture (IITA). Check varieties, Pan 6479 (a hybrid) and three locally grown OPVs (Okavango, Afric 1 and Nelson‘s Choice) were also included. Participatory variety selection (PVS) was conducted during the 2009/10 summer season to evaluate farmer acceptance of these newly introduced OPVs. The most preferred varieties farmers were Okavango, ZM 305 and ZM 501, and these varieties were not significantly different from the highest yielding variety within each site. Therefore, varieties like ZM 305 and ZM 501 could easily be adopted by farmers, and their use could result in yield improvements. To gather information on farmer characteristics, and perceptions on maize production constraints and maize selection criteria, focus group discussions and household surveys were conducted during the 2009/2010 and 2010/2011 seasons, respectively. Results indicated that, elderly farmers dominated the farming communities. Maize production was generally low, with 98percent of the farmers obtaining less than 1.6 t/ha. The most important constraints affecting maize production were extreme weather events (floods and drought), pests and diseases, and poor access to credit. The most preferred traits that made up farmer selection criteria were ear traits such as taste, long cobs, and big kernels. Other traits, such as, prolificacy, early maturity, retainability of seed and dark leaves, were village specific. Yield trials, assessing genotype and environment interactions, were conducted in eight sites during the 2009/10 and 2010/11 seasons. The genotypes exhibited non-significant crossover and non-crossover GEI over the environments. Okavango, the most stable variety, was generally low yielding (4.28 t/ha) than other stable varieties such as ZM 305, ZM 501, ZM 621 and ZM 423. The later varieties had significantly (p<0.05) higher yields of between 4.46 t/ha and 4.97 t/ha. The highest yielding varieties, Pan 6479 (5.29 t/ha) and ZM 525 (4.87 t/ha), showed specific adaptations to high potential environments, while BR 993 (4.07 t/ha) and Afric 1 (4.24 t/ha) were low yielding, unstable and specifically adapted to low potential environments. New varieties, therefore, exhibited both specific and wide adaptation. Qualitative and quantitative traits were evaluated to establish the morphological diversity of the 13 varieties. Ear height, plant height, days to 50percent anthesis and grain yield contributed the most to variety diversity. Cluster Analysis discriminated varieties into four main clusters. The first cluster consisted of four CIMMYT varieties that were short in height and early maturing (ZM 305, ZM 423, ZM 501 and ZM 525), while hybrid Pan 6479 was placed into cluster two. Nelson‘s Choice and Okavango were grouped into the third cluster, while tall and late maturing varieties, ZM 621, ZM 627, Obatanpa, BR 993, Comp 4 and Afric 1, were placed in the fourth cluster. The segregation of the newly introduced varieties into two distinct groups shows that these varieties can be recommended into more than on cropping system and agro-ecology. Differences in village agro-ecologies resulted in farmers selecting varieties differently. This diversity in agro-ecology also brought about variations on farmer perceptions in selection criteria and production constraints. Most of the new varieties were observed to be superior in yield performance when compared to local check OPVs, exhibiting either wide or specific adaptation. The study also demonstrated that, the study of morphological diversity can be used to suggest varieties to different environmental potentials and cropping systems. Multi-evaluation trials were able to give an insight on variety preferences and performance. These new varieties should, therefore, be introduced to selected farmers living in their respective environments on the basis of results obtained. However, varieties still need to be evaluated under farmer-managed conditions to determine whether they actually bring about yield improvement when compared with current varieties being used. , Thesis (MSc) -- Faculty of Science and Agriculture, 2011
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The impact of HIV/AIDS on the delivery of maternal health care services of selected primary health care clinics of Peddie in the Eastern Cape Province
- Mangi, Nozuko Glenrose https://orcid.org/0000-0001-9158-8820
- Authors: Mangi, Nozuko Glenrose https://orcid.org/0000-0001-9158-8820
- Date: 2011
- Subjects: Maternal health services , Primary health care , HIV infections -- Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/24576 , vital:63209
- Description: The aim of this descriptive study was to explore the impact of HIV/AIDS on the maternal health programme at selected Primary Health Care (PHC) clinics in the Peddie sub-district, in the Eastern Cape, South Africa. This study showed that the HIV/AIDS epidemic has had major influences on the rendering of maternal health services in this sub-district. An understanding of the impact of HIV/AIDS on the delivery of the maternal health programme in the Peddie Primary Health Clinics will potentially help the District Health Service office, as well as the clinic managers and professional nurses to formulate strategies to strengthen the maternal health programme. This data will also be helpful when developing plans to cope with the heavy work-load of the clinics offering maternal health services, and to address the attitudes and concerns of the professional nurses working in the PHC clinics in this area. Thirty professional nurses working at 10 clinics responded to the questionnaires which elicited questions pertaining to the impact of HIV/AIDS on the rendering of their services. As part of the data gathering procedures, standardised notice boards at the PHC clinics were used to document the services rendered. The numbers of ANC clients attended to each of the clinics per week were collected in routine attendance tick registers used in the clinics for recording and monitoring statistics in the maternal health programme. The data was analysed to examine the possible impact of HIV/AIDS on maternal health services rendered by registered nurses/midwives working in the PHC clinics. The registered nurses who responded to the questionnaires (Annexure H) made several suggestions. These included the following: (i) encouraged more training (11 nurses), (ii) addition of more staff members, (iii) to have specialized staff for management of maternal HIV. Because of the study limitations such as the sample size of 10 clinics with a total of 30 nurses who were studied, the study may not be generalised to the whole of the Eastern Cape Province. The study however did provide baseline information on the impact of HIV/AIDS on the maternal health programme. The study findings were that HIV/AIDS has had an impact on the delivery of the maternal health programme due to the extra services brought about by the response to the HIV/AIDS pandemic. This study will contribute to a better understanding of the impact of HIV/AIDS on the maternal health programme at the PHC level in Peddie. The research provided insight into issues that are crucial to the delivery of maternal health programmes in rural areas. , Thesis (MCur) -- Faculty of Science and Agriculture, 2011
- Full Text:
- Authors: Mangi, Nozuko Glenrose https://orcid.org/0000-0001-9158-8820
- Date: 2011
- Subjects: Maternal health services , Primary health care , HIV infections -- Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/24576 , vital:63209
- Description: The aim of this descriptive study was to explore the impact of HIV/AIDS on the maternal health programme at selected Primary Health Care (PHC) clinics in the Peddie sub-district, in the Eastern Cape, South Africa. This study showed that the HIV/AIDS epidemic has had major influences on the rendering of maternal health services in this sub-district. An understanding of the impact of HIV/AIDS on the delivery of the maternal health programme in the Peddie Primary Health Clinics will potentially help the District Health Service office, as well as the clinic managers and professional nurses to formulate strategies to strengthen the maternal health programme. This data will also be helpful when developing plans to cope with the heavy work-load of the clinics offering maternal health services, and to address the attitudes and concerns of the professional nurses working in the PHC clinics in this area. Thirty professional nurses working at 10 clinics responded to the questionnaires which elicited questions pertaining to the impact of HIV/AIDS on the rendering of their services. As part of the data gathering procedures, standardised notice boards at the PHC clinics were used to document the services rendered. The numbers of ANC clients attended to each of the clinics per week were collected in routine attendance tick registers used in the clinics for recording and monitoring statistics in the maternal health programme. The data was analysed to examine the possible impact of HIV/AIDS on maternal health services rendered by registered nurses/midwives working in the PHC clinics. The registered nurses who responded to the questionnaires (Annexure H) made several suggestions. These included the following: (i) encouraged more training (11 nurses), (ii) addition of more staff members, (iii) to have specialized staff for management of maternal HIV. Because of the study limitations such as the sample size of 10 clinics with a total of 30 nurses who were studied, the study may not be generalised to the whole of the Eastern Cape Province. The study however did provide baseline information on the impact of HIV/AIDS on the maternal health programme. The study findings were that HIV/AIDS has had an impact on the delivery of the maternal health programme due to the extra services brought about by the response to the HIV/AIDS pandemic. This study will contribute to a better understanding of the impact of HIV/AIDS on the maternal health programme at the PHC level in Peddie. The research provided insight into issues that are crucial to the delivery of maternal health programmes in rural areas. , Thesis (MCur) -- Faculty of Science and Agriculture, 2011
- Full Text:
Evaluation and comparison of rural and industrial brick masonry units for sustainabile low cost housing
- Authors: Maweza, Elijah Loyiso
- Date: 2011-01
- Subjects: Masonry
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/24923 , vital:63676
- Description: The lack of adequate housing for the rural population of South Africa is experienced in every community. The South African government has drawn policies, strategies and required standards that must govern the provision of housing to the people. One of the required standards of housing is that the walls be constructed in such a way that they are able to adequately resist water penetration into any part of the building where it would be detrimental to the health of the occupants or the lifespan of the building. This research took the investigation of the characteristics of bricks that increase or reduce water absorption by bricks as the main objective. The investigation looked first at the raw materials of bricks, the soils and clay. The particle size related soil fractions were investigated because particle sizes are directly linked to the porosity of the bricks. Porosity describes the percentage of pores that are in the bricks, which show the extent to which bricks can internally accommodate moisture. Soil mineralogy was also discussed because as bricks are fired, the changes that they undergo affect the mineralogy of the bricks. The manufacturing procedures (brick moulding and firing) as reported from literature are briefly discussed in chapter 2. The effect of heat on clays is also discussed in order to explain the changes that occur as a result of firing. The porosity and the sorptivity of bricks were the relevant brick properties that are discussed. The methods employed to investigate the characteristics of bricks as discussed in chapter 3 were as follows: (i) Winning and preparation of raw materials. (ii) Particle size analysis. (iii) Water and carbon content in newly formed rural and industrial bricks. (iv) The firing procedures and temperature distribution investigation. (v) The chemical composition of rural and industrial bricks. (vi) Porosity. (vii) The Neutron Radiography equipment and operations. (viii) Sorptivity. With these investigations it was discovered that the quality of the bricks can be improved by: (i) Selecting and preparing the raw materials. This can be done by considering the soil types and reducing the soil particle sizes by sieving and grinding. (ii) Moulding the bricks properly by thoroughly working the soil, reducing the water content and increasing compaction. (iii) Drying the bricks using the sun and the exhaust heat from the kilns that are firing bricks at the time. (iv) Adopting brick firing techniques that produce the desired bricks more efficiently. , Thesis (MSc) -- Faculty of Science and Agriculture, 2011
- Full Text:
- Authors: Maweza, Elijah Loyiso
- Date: 2011-01
- Subjects: Masonry
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/24923 , vital:63676
- Description: The lack of adequate housing for the rural population of South Africa is experienced in every community. The South African government has drawn policies, strategies and required standards that must govern the provision of housing to the people. One of the required standards of housing is that the walls be constructed in such a way that they are able to adequately resist water penetration into any part of the building where it would be detrimental to the health of the occupants or the lifespan of the building. This research took the investigation of the characteristics of bricks that increase or reduce water absorption by bricks as the main objective. The investigation looked first at the raw materials of bricks, the soils and clay. The particle size related soil fractions were investigated because particle sizes are directly linked to the porosity of the bricks. Porosity describes the percentage of pores that are in the bricks, which show the extent to which bricks can internally accommodate moisture. Soil mineralogy was also discussed because as bricks are fired, the changes that they undergo affect the mineralogy of the bricks. The manufacturing procedures (brick moulding and firing) as reported from literature are briefly discussed in chapter 2. The effect of heat on clays is also discussed in order to explain the changes that occur as a result of firing. The porosity and the sorptivity of bricks were the relevant brick properties that are discussed. The methods employed to investigate the characteristics of bricks as discussed in chapter 3 were as follows: (i) Winning and preparation of raw materials. (ii) Particle size analysis. (iii) Water and carbon content in newly formed rural and industrial bricks. (iv) The firing procedures and temperature distribution investigation. (v) The chemical composition of rural and industrial bricks. (vi) Porosity. (vii) The Neutron Radiography equipment and operations. (viii) Sorptivity. With these investigations it was discovered that the quality of the bricks can be improved by: (i) Selecting and preparing the raw materials. This can be done by considering the soil types and reducing the soil particle sizes by sieving and grinding. (ii) Moulding the bricks properly by thoroughly working the soil, reducing the water content and increasing compaction. (iii) Drying the bricks using the sun and the exhaust heat from the kilns that are firing bricks at the time. (iv) Adopting brick firing techniques that produce the desired bricks more efficiently. , Thesis (MSc) -- Faculty of Science and Agriculture, 2011
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Optimizing geochemical sampling sizes and quantifying uncertainties for environmental risk assessment using Anglogold-Ashanti Gold Mines as a case study
- Authors: Chihobvu, Elizabeth
- Date: 2010-04
- Subjects: Environmental risk assessment , Geochemical prospecting
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/24443 , vital:62796
- Description: Generally, and particularly in South Africa, limited work done on the development of methodologies for sample sizing and quantifying uncertainties in geochemical sampling and analyses. As a result, little trust is placed on the long-term predictions of geochemical modelling for Environmental Risk Assessment (E.R.A). In addition, this leads to the slow approval of mining authorisations, water use licenses and mine closure plans. This dissertation addresses this deficiency in geochemical sampling and analyses specifically for ERA and proposes two methodologies (i) for quantifying uncertainties in geochemical sampling and analysis as a function of sample size and analyses and (ii) for determining the optimum sample size to ensure data quality. The statistical analysis approach was adopted as the best method for sample size determination. The approach is based on the premise that the size of the study sample is critical to producing meaningful results. The size of the required samples depends on a number of factors including purpose of the study, available budget, variability of the population being sampled, acceptable errors and confidence level. The methodology for estimating uncertainty is a fusion of existing methodologies for quantifying measurement uncertainty. The methodology takes a holistic view of the measurement process to include all processes involved in obtaining measurement results as possible uncertainty components. Like the statistical analysis approach, the methodology employs basic statistical principles in estimating the size of uncertainty, associated with a given measurement result. The approach identifies each component of uncertainty; estimates the size of each component and sums the contribution of each component in order to approximate the overall uncertainty value, associated with a given measurement result. The two methods were applied to Acid-Base Accounting (ABA) data derived from geochemical assessment for ERA of the West Wits and Vaal River (Ashanti Gold mines) tailings dams undertaken by Pulles and Howard de Lange Inc. on behalf of AngloGold Ltd. The study was aimed at assessing and evaluating the potential of tailings dams in the two mining areas to impact on water quality and implications of this in terms of mine closure and rehabilitation. Findings from this study show that the number of samples needed is influenced by the purpose of the study, size of the target area, nature and type of material, budget, acceptable error and the confidence level required, among other factors. Acceptable error has an exponential relationship with sample size hence one can minimize error by increasing sample size. While a low value of acceptable error value and high confidence are always desirable, a tradeoff among these competing factors must be found, given the usually limited funds and time. The findings also demonstrated that uncertainties in geochemical sampling and analysis are unavoidable. They arise from the fact that only a small portion of the population rather than a census is used to derive conclusions about certain characteristics of the target population. This is further augmented by other influential quantities that affect the accuracy of the estimates. Effects such as poor sampling design, inadequate sample size, sample heterogeneity and other factors highly affect data quality and representivity hence measurement uncertainty. Among these factors, those associated with sampling, mainly heterogeneity was found to be the strongest contributing factor toward overall uncertainty. This implies an increased proportion of expenditure should be channelled toward sampling to minimise uncertainty. Uncertainties can be reduced by adopting good sampling practices and increasing sample size, among other methods. It is recommended that more information be made available for proper uncertainty analysis. , Thesis (MSc) -- Faculty of Science and Agriculture, 2010
- Full Text:
- Authors: Chihobvu, Elizabeth
- Date: 2010-04
- Subjects: Environmental risk assessment , Geochemical prospecting
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/24443 , vital:62796
- Description: Generally, and particularly in South Africa, limited work done on the development of methodologies for sample sizing and quantifying uncertainties in geochemical sampling and analyses. As a result, little trust is placed on the long-term predictions of geochemical modelling for Environmental Risk Assessment (E.R.A). In addition, this leads to the slow approval of mining authorisations, water use licenses and mine closure plans. This dissertation addresses this deficiency in geochemical sampling and analyses specifically for ERA and proposes two methodologies (i) for quantifying uncertainties in geochemical sampling and analysis as a function of sample size and analyses and (ii) for determining the optimum sample size to ensure data quality. The statistical analysis approach was adopted as the best method for sample size determination. The approach is based on the premise that the size of the study sample is critical to producing meaningful results. The size of the required samples depends on a number of factors including purpose of the study, available budget, variability of the population being sampled, acceptable errors and confidence level. The methodology for estimating uncertainty is a fusion of existing methodologies for quantifying measurement uncertainty. The methodology takes a holistic view of the measurement process to include all processes involved in obtaining measurement results as possible uncertainty components. Like the statistical analysis approach, the methodology employs basic statistical principles in estimating the size of uncertainty, associated with a given measurement result. The approach identifies each component of uncertainty; estimates the size of each component and sums the contribution of each component in order to approximate the overall uncertainty value, associated with a given measurement result. The two methods were applied to Acid-Base Accounting (ABA) data derived from geochemical assessment for ERA of the West Wits and Vaal River (Ashanti Gold mines) tailings dams undertaken by Pulles and Howard de Lange Inc. on behalf of AngloGold Ltd. The study was aimed at assessing and evaluating the potential of tailings dams in the two mining areas to impact on water quality and implications of this in terms of mine closure and rehabilitation. Findings from this study show that the number of samples needed is influenced by the purpose of the study, size of the target area, nature and type of material, budget, acceptable error and the confidence level required, among other factors. Acceptable error has an exponential relationship with sample size hence one can minimize error by increasing sample size. While a low value of acceptable error value and high confidence are always desirable, a tradeoff among these competing factors must be found, given the usually limited funds and time. The findings also demonstrated that uncertainties in geochemical sampling and analysis are unavoidable. They arise from the fact that only a small portion of the population rather than a census is used to derive conclusions about certain characteristics of the target population. This is further augmented by other influential quantities that affect the accuracy of the estimates. Effects such as poor sampling design, inadequate sample size, sample heterogeneity and other factors highly affect data quality and representivity hence measurement uncertainty. Among these factors, those associated with sampling, mainly heterogeneity was found to be the strongest contributing factor toward overall uncertainty. This implies an increased proportion of expenditure should be channelled toward sampling to minimise uncertainty. Uncertainties can be reduced by adopting good sampling practices and increasing sample size, among other methods. It is recommended that more information be made available for proper uncertainty analysis. , Thesis (MSc) -- Faculty of Science and Agriculture, 2010
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Assessment of antibiotic production by some marine actinomycetes belonging to the genera norcadia, saccharopolyspora and kibdellosporangium.
- Koba, Siziwe (https://orcid.org/0000-0002-6761-6403)
- Authors: Koba, Siziwe (https://orcid.org/0000-0002-6761-6403)
- Date: 2010
- Subjects: Actinobacteria , Bacteria , Actinomycetales
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/25811 , vital:64488
- Description: Antibacterial potency of the extracts of the three marine actinomycetes strains which were isolated in the Nahoon Beach and tentatively identified as the genera Norcadia, Kibdellosporingium and Saccharopolyspora were investigated in this study against a panel of referenced, environmental and clinical bacterial strains. The ethyl acetate extracts of these marine actinomycetes were screened for activity against 32 bacterial isolates. Out of the 32 organisms, 10 were susceptible to one or all the extracts used. Antibacterial activity was mainly observed against Gram-negative organisms with Minimum inhibitory concentration (MIC) values ranging from 0.078 mg/ml to >10mg/ml. The killing rates of the active extracts were also elucidated using standard procedures. The two extracts NO64 and NO53 showed rapid bactericidal activity against B. pumilus ATCC 14884 and Serratia marcens with a 3Log10 reduction in counts within 6 hours at 3.75 mg/ml and 5 mg/ml respectively. In conclusion, the ethyl acetate extract of these marine actinomycetes strains possess strong bactericidal and bacteriostatic activities against Gram negative organisms and can be therapeutically useful in the treatment of bacterial infections which are mainly caused by Gram negative bacteria. , Thesis (MA) -- Faculty of Science and Agriculture, 2010
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- Authors: Koba, Siziwe (https://orcid.org/0000-0002-6761-6403)
- Date: 2010
- Subjects: Actinobacteria , Bacteria , Actinomycetales
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/25811 , vital:64488
- Description: Antibacterial potency of the extracts of the three marine actinomycetes strains which were isolated in the Nahoon Beach and tentatively identified as the genera Norcadia, Kibdellosporingium and Saccharopolyspora were investigated in this study against a panel of referenced, environmental and clinical bacterial strains. The ethyl acetate extracts of these marine actinomycetes were screened for activity against 32 bacterial isolates. Out of the 32 organisms, 10 were susceptible to one or all the extracts used. Antibacterial activity was mainly observed against Gram-negative organisms with Minimum inhibitory concentration (MIC) values ranging from 0.078 mg/ml to >10mg/ml. The killing rates of the active extracts were also elucidated using standard procedures. The two extracts NO64 and NO53 showed rapid bactericidal activity against B. pumilus ATCC 14884 and Serratia marcens with a 3Log10 reduction in counts within 6 hours at 3.75 mg/ml and 5 mg/ml respectively. In conclusion, the ethyl acetate extract of these marine actinomycetes strains possess strong bactericidal and bacteriostatic activities against Gram negative organisms and can be therapeutically useful in the treatment of bacterial infections which are mainly caused by Gram negative bacteria. , Thesis (MA) -- Faculty of Science and Agriculture, 2010
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Synthesis of bioethanol from lignocellulosic materials: A focus on grass and waste paper as raw materials
- Authors: Vala, Mavula Kikwe
- Date: 2009-12
- Subjects: Ethanol as fuel , Biomass energy , Lignocellulose -- Biotechnology
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/24499 , vital:63049
- Description: Biofuels are currently recognized as not only a necessity, but an inevitable pathway to secure the planet future energy needs. Food crops have been used (so far) as the biomass for bioethanol and biodiesel production. This has increased concerns over food security and led to the search for diversification and alternative feedstocks for biofuel production. The use of lignocellulosic materials, the most abundant, low cost and easy feedstock to harvest for bioethanol purpose, involves challenging production processes. Several approaches have been used to facilitate the breakdown of the biopolymer structure to produce fermentable sugars that can be converted to ethanol. Most of the approaches have used high temperatures and pressures and have often led to the production of inhibitors of fermentation. In this study, lignocellulosic materials from grass and newsprint were investigated as sources of biomass for bioethanol production using a chemical route (sulfuric acid hydrolysis) which made use of temperatures below 100°C at normal atmospheric pressure. Fermentation of toxic lignocellulosic hydrolyzates was possible after the development of a method for inhibitors removal. The method used treated wood chips as a stationary phase in a chromatographic column to remove inhibitors. This method is expected to be extended to applications such as in municipal wastewater treatment. Sugar yields of 22.26 and 8.9 g/L of hydrolyzate; and an ethanol yield of 184.5 and 130.4 mg/mL of must were achieved for 5g grass and newsprint respectively using optimum conditions of 2percent H2SO4 at 97.5°C for grass and 0.5percent H2SO4 at 97.5°C for newsprint during the hydrolysis process. Pure cellulose was used as a control for the biomass where 254.1 g/L of fermentable sugars were recovered from soluble cellulose and the yield of ethanol was 201.8 mg/mL. , Thesis (MSc) -- Faculty of Science and Agriculture, 2009
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- Authors: Vala, Mavula Kikwe
- Date: 2009-12
- Subjects: Ethanol as fuel , Biomass energy , Lignocellulose -- Biotechnology
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/24499 , vital:63049
- Description: Biofuels are currently recognized as not only a necessity, but an inevitable pathway to secure the planet future energy needs. Food crops have been used (so far) as the biomass for bioethanol and biodiesel production. This has increased concerns over food security and led to the search for diversification and alternative feedstocks for biofuel production. The use of lignocellulosic materials, the most abundant, low cost and easy feedstock to harvest for bioethanol purpose, involves challenging production processes. Several approaches have been used to facilitate the breakdown of the biopolymer structure to produce fermentable sugars that can be converted to ethanol. Most of the approaches have used high temperatures and pressures and have often led to the production of inhibitors of fermentation. In this study, lignocellulosic materials from grass and newsprint were investigated as sources of biomass for bioethanol production using a chemical route (sulfuric acid hydrolysis) which made use of temperatures below 100°C at normal atmospheric pressure. Fermentation of toxic lignocellulosic hydrolyzates was possible after the development of a method for inhibitors removal. The method used treated wood chips as a stationary phase in a chromatographic column to remove inhibitors. This method is expected to be extended to applications such as in municipal wastewater treatment. Sugar yields of 22.26 and 8.9 g/L of hydrolyzate; and an ethanol yield of 184.5 and 130.4 mg/mL of must were achieved for 5g grass and newsprint respectively using optimum conditions of 2percent H2SO4 at 97.5°C for grass and 0.5percent H2SO4 at 97.5°C for newsprint during the hydrolysis process. Pure cellulose was used as a control for the biomass where 254.1 g/L of fermentable sugars were recovered from soluble cellulose and the yield of ethanol was 201.8 mg/mL. , Thesis (MSc) -- Faculty of Science and Agriculture, 2009
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Numerical quadrature of oscillatory and non-oscillatory integrals
- Dukuza, Kenneth Njengele https://orcid.org/0000-0002-4525-7390
- Authors: Dukuza, Kenneth Njengele https://orcid.org/0000-0002-4525-7390
- Date: 2009
- Subjects: Oscillations , Numerical integration , Numerical analysis
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/24304 , vital:62600
- Description: In this dissertation we develop efficient new methods and techniques to numerically evaluate integrals of both oscillatory and non oscillatory kind. We have done a comprehensive literature review on the existing methods and made some modifications to them so as to cope with difficulties such as oscillations and strong singularities. In the numerical algorithms we have used mainly the MATLAB source code. Our results have been compared with well known methods by renowned authors in this field. , Thesis (MSc) -- Faculty of Science and Agriculture, 2009
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- Authors: Dukuza, Kenneth Njengele https://orcid.org/0000-0002-4525-7390
- Date: 2009
- Subjects: Oscillations , Numerical integration , Numerical analysis
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/24304 , vital:62600
- Description: In this dissertation we develop efficient new methods and techniques to numerically evaluate integrals of both oscillatory and non oscillatory kind. We have done a comprehensive literature review on the existing methods and made some modifications to them so as to cope with difficulties such as oscillations and strong singularities. In the numerical algorithms we have used mainly the MATLAB source code. Our results have been compared with well known methods by renowned authors in this field. , Thesis (MSc) -- Faculty of Science and Agriculture, 2009
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Photovoltaic-powered wireless communication system for rural schools outside national utility grid
- Kaseke, Richmore https://orcid.org/0000-0002-8295-5016
- Authors: Kaseke, Richmore https://orcid.org/0000-0002-8295-5016
- Date: 2007-02
- Subjects: Photovoltaic system
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/25483 , vital:64284
- Description: Access to global information is inarguably one of the key ways of bringing development to any community. In developing worlds, many rural schools lie outside both the Internet Service Provider’s (ISP) cable network and the national utility grid. Rapid developments in information and communication technology (ICT) continue to widen the digital divide between urban and rural schools. In South Africa, although these rural areas are outside the ISP’s cable network, they enjoy excellent mobile (cellular) communications network coverage. Fortunately, leading mobile operators in the country (MTN and Vodacom) have incorporated mobile data packet services into their cellular communication networks since 2002. A stand-alone photovoltaic (PV) system for powering ICT equipment in off grid rural schools was designed and installed; and its performance monitored. Performance of the system was considered in two categories, which are; cost and service performance. In cost performance, return on investment (ROI) and payback period (PB) are the two critical considerations. The PV system designed in this study gave an impressive ROI and PB of 286percent and 5 years, respectively. In order to monitor and evaluate the service performance a data acquisition system (DAS) was designed and installed. Besides proving the potential of PV in powering ICT equipment, results from the DAS also suggested a more efficient way of employing PV as a power source for powering equipment that is based on Switched-Mode Power Supply Units. Concurrent and continuous change in irradiance and temperature result in a four-segment pattern of rising and falling module efficiency throughout the day. Generally, modules produce more energy on cooler sunny days than hotter sunny days. Infrared (IR) Thermography was also used as part of both indoor and outdoor module tests. During indoor tests at pre-deployment stage, IR Thermography showed development of hot spots in mismatched cells of reverse-biased modules. On the outdoors, IR Thermography reiterated the effect of bird droppings on module surfaces by showing hot spots forming on areas covered by the droppings. For internet connectivity, a customized Mobile Internet Device (MIDevice) was designed, built and tested. The device allows remote computer systems to be connected to the Internet via the already existing mobile communication network k using General Packet Radio Services (GPRS). An entire rural school local area network (LAN) can be connected to the Internet via a single MIDevice. An experimental setup was designed in order to monitor and evaluate performance of GPRS in specific and mobile Internet solutions in general. Results obtained proved that GPRS can indeed be a solution for remote Internet connectivity in rural schools. In order to improve performance of GPRS or mobile Internet connections, caching, pop-up blocking and proxy filtering are necessary. , Thesis (MSc) -- Faculty of Science and Agriculture, 2007
- Full Text:
- Authors: Kaseke, Richmore https://orcid.org/0000-0002-8295-5016
- Date: 2007-02
- Subjects: Photovoltaic system
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/25483 , vital:64284
- Description: Access to global information is inarguably one of the key ways of bringing development to any community. In developing worlds, many rural schools lie outside both the Internet Service Provider’s (ISP) cable network and the national utility grid. Rapid developments in information and communication technology (ICT) continue to widen the digital divide between urban and rural schools. In South Africa, although these rural areas are outside the ISP’s cable network, they enjoy excellent mobile (cellular) communications network coverage. Fortunately, leading mobile operators in the country (MTN and Vodacom) have incorporated mobile data packet services into their cellular communication networks since 2002. A stand-alone photovoltaic (PV) system for powering ICT equipment in off grid rural schools was designed and installed; and its performance monitored. Performance of the system was considered in two categories, which are; cost and service performance. In cost performance, return on investment (ROI) and payback period (PB) are the two critical considerations. The PV system designed in this study gave an impressive ROI and PB of 286percent and 5 years, respectively. In order to monitor and evaluate the service performance a data acquisition system (DAS) was designed and installed. Besides proving the potential of PV in powering ICT equipment, results from the DAS also suggested a more efficient way of employing PV as a power source for powering equipment that is based on Switched-Mode Power Supply Units. Concurrent and continuous change in irradiance and temperature result in a four-segment pattern of rising and falling module efficiency throughout the day. Generally, modules produce more energy on cooler sunny days than hotter sunny days. Infrared (IR) Thermography was also used as part of both indoor and outdoor module tests. During indoor tests at pre-deployment stage, IR Thermography showed development of hot spots in mismatched cells of reverse-biased modules. On the outdoors, IR Thermography reiterated the effect of bird droppings on module surfaces by showing hot spots forming on areas covered by the droppings. For internet connectivity, a customized Mobile Internet Device (MIDevice) was designed, built and tested. The device allows remote computer systems to be connected to the Internet via the already existing mobile communication network k using General Packet Radio Services (GPRS). An entire rural school local area network (LAN) can be connected to the Internet via a single MIDevice. An experimental setup was designed in order to monitor and evaluate performance of GPRS in specific and mobile Internet solutions in general. Results obtained proved that GPRS can indeed be a solution for remote Internet connectivity in rural schools. In order to improve performance of GPRS or mobile Internet connections, caching, pop-up blocking and proxy filtering are necessary. , Thesis (MSc) -- Faculty of Science and Agriculture, 2007
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Assessment of antibacterial potentials of Garcinia Kola seed extracts and their interactions with antibiotics
- Authors: Sibanda, Thulani
- Date: 2007
- Subjects: Drug resistance in microorganisms , Garcinia , Antibiotics
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/19236 , vital:43038
- Description: The antibacterial potency of the extracts of the seed of Garcinia kola (bitter kola) was investigated in this study against a panel of referenced, environmental and clinical bacterial strains. The killing rates of the active extract as well as their potential for combination antibacterial therapy with standard antibiotics were also elucidated using standard procedures. The aqueous and acetone extracts of the seed were screened for activity against 27 bacterial isolates. The aqueous extract exhibited activity mainly against Gram positive organisms with Minimum inhibitory concentration (MIC) values ranging from 5 mgml-1 – 20 mgml-1, while the acetone extract showed activity against both Gram negative and Gram positive organisms with MIC values ranging from 10 mgml-1 - 0.156 mgml-1. The acetone extract also showed rapid bactericidal activity against Staphylococcus aureus ATCC 6538 with a 3.097 Log10 reduction in counts within 4 hours at 0.3125 mgml-1 and a 1.582 Log10 reduction against Proteus vulgaris CSIR 0030 at 5 mgml-1 after 1 hour. In addition, the aqueous, methanol and acetone extracts of the seeds also exhibited activity against four clinical strains of Staphylococcus isolated from wound sepsis specimens. The MIC values for the aqueous extract were 10 mgml-1 for all the isolates while the acetone and methanol extracts had lower values ranging from 0.3125 - 0.625 mgml-1. The acetone extract was strongly bactericidal against Staphylococcus aureus OKOH3 resulting in a 2.70 Log10 reduction in counts at 1.25 mgml-1 within 4 hours of exposure and a complete elimination of the organism after 8 hours. The bactericidal activity of the same extract against Staphylococcus aureus OKOH1 was weak, achieving only a 2.92 Log10 reduction in counts at 1.25 mgml-1 (4× MIC) in 24 hours. In the test for interactions between the acetone extract of the seeds and antibiotics, synergistic interactions were observed largely against Gram positive organisms using the FIC indices, (indices of 0.52 - 0.875) with combinations against Gram negatives yielding largely antagonistic interactions (indices of 2.0 to 5.0). Synergy (≥ 1000 times or ≥ 3 Log10 potentiation of the bactericidal activity) against both Gram negative and Gram positive organisms was detected by time kill assays mainly involving the antibiotics tetracycline, chloramphenicol, amoxycillin and penicillin G. Combinations involving erythromycin and ciprofloxacin consistently gave antagonistic or indifferent interactions. We conclude that the acetone extract of Garcinia kola seeds possess strong bactericidal activities against both Gram positive and Gram negative organisms and can be therapeutically useful in the treatment of bacterial infections including the problematic staphylococcal wound infections. In addition, the acetone extract can be a potential source of broad spectrum resistance modifying compounds that can potentially improve the performance of antibiotics in the treatment of drug resistant infections. , Thesis (MSc)-- Microbiology, University of Fort Hare, 2007
- Full Text:
- Authors: Sibanda, Thulani
- Date: 2007
- Subjects: Drug resistance in microorganisms , Garcinia , Antibiotics
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/19236 , vital:43038
- Description: The antibacterial potency of the extracts of the seed of Garcinia kola (bitter kola) was investigated in this study against a panel of referenced, environmental and clinical bacterial strains. The killing rates of the active extract as well as their potential for combination antibacterial therapy with standard antibiotics were also elucidated using standard procedures. The aqueous and acetone extracts of the seed were screened for activity against 27 bacterial isolates. The aqueous extract exhibited activity mainly against Gram positive organisms with Minimum inhibitory concentration (MIC) values ranging from 5 mgml-1 – 20 mgml-1, while the acetone extract showed activity against both Gram negative and Gram positive organisms with MIC values ranging from 10 mgml-1 - 0.156 mgml-1. The acetone extract also showed rapid bactericidal activity against Staphylococcus aureus ATCC 6538 with a 3.097 Log10 reduction in counts within 4 hours at 0.3125 mgml-1 and a 1.582 Log10 reduction against Proteus vulgaris CSIR 0030 at 5 mgml-1 after 1 hour. In addition, the aqueous, methanol and acetone extracts of the seeds also exhibited activity against four clinical strains of Staphylococcus isolated from wound sepsis specimens. The MIC values for the aqueous extract were 10 mgml-1 for all the isolates while the acetone and methanol extracts had lower values ranging from 0.3125 - 0.625 mgml-1. The acetone extract was strongly bactericidal against Staphylococcus aureus OKOH3 resulting in a 2.70 Log10 reduction in counts at 1.25 mgml-1 within 4 hours of exposure and a complete elimination of the organism after 8 hours. The bactericidal activity of the same extract against Staphylococcus aureus OKOH1 was weak, achieving only a 2.92 Log10 reduction in counts at 1.25 mgml-1 (4× MIC) in 24 hours. In the test for interactions between the acetone extract of the seeds and antibiotics, synergistic interactions were observed largely against Gram positive organisms using the FIC indices, (indices of 0.52 - 0.875) with combinations against Gram negatives yielding largely antagonistic interactions (indices of 2.0 to 5.0). Synergy (≥ 1000 times or ≥ 3 Log10 potentiation of the bactericidal activity) against both Gram negative and Gram positive organisms was detected by time kill assays mainly involving the antibiotics tetracycline, chloramphenicol, amoxycillin and penicillin G. Combinations involving erythromycin and ciprofloxacin consistently gave antagonistic or indifferent interactions. We conclude that the acetone extract of Garcinia kola seeds possess strong bactericidal activities against both Gram positive and Gram negative organisms and can be therapeutically useful in the treatment of bacterial infections including the problematic staphylococcal wound infections. In addition, the acetone extract can be a potential source of broad spectrum resistance modifying compounds that can potentially improve the performance of antibiotics in the treatment of drug resistant infections. , Thesis (MSc)-- Microbiology, University of Fort Hare, 2007
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