Critical assessment of the quartz crystal microbalance with dissipation as an analytical tool for biosensor development and fundamental studies
- Fogel, Ronen, Mashazi, Philani N, Nyokong, Tebello, Limson, Janice
- Authors: Fogel, Ronen , Mashazi, Philani N , Nyokong, Tebello , Limson, Janice
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/271204 , vital:54521 , xlink:href="https://doi.org/10.1016/j.bios.2007.03.012"
- Description: One of the challenges in electrochemical biosensor design is gaining a fundamental knowledge of the processes underlying immobilisation of the molecules onto the electrode surface. This is of particular importance in biocomposite sensors where concerns have arisen as to the nature of the interaction between the biological and synthetic molecules immobilised. We examined the use of the Quartz Crystal Microbalance with Dissipation (QCM-D) as a tool for fundamental analyses of a model sensor constructed by the immobilisation of cobalt(II) phthalocyanine (TCACoPc) and glucose oxidase (GOx) onto a gold-quartz electrode (electrode surface) for the enhanced detection of glucose. The model sensor was constructed in aqueous phase and covalently linked the gold surface to the TCACoPc, and the TCACoPc to the GOx, using the QCM-D. The aqueous metallophthalocyanine (MPc) formed a multi-layer over the surface of the electrode, which could be removed to leave a monolayer with a mass loading that compared favourably to the theoretical value expected. Analysis of frequency and dissipation plots indicated covalent attachment of glucose oxidase onto the metallophthalocyanine layer. The amount of GOx bound using the model system compared favourably to calculations derived from the maximal amperometric functioning of the electrochemical sensor (examined in previously-published literature, Mashazi, P.N., Ozoemena, K.I., Nyokong, T., 2006. Electrochim. Acta 52, 177–186), but not to theoretical values derived from dimensions of GOx as established by crystallography. The strength of the binding of the GOx film with the TCACoPc layer was tested by using 2% SDS as a denaturant/surfactant, and the GOx film was not found to be significantly affected by exposure to this. This paper thus showed that QCM-D can be used in order to model essential processes and interactions that dictate the functional parameters of a biosensor.
- Full Text:
- Date Issued: 2007
- Authors: Fogel, Ronen , Mashazi, Philani N , Nyokong, Tebello , Limson, Janice
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/271204 , vital:54521 , xlink:href="https://doi.org/10.1016/j.bios.2007.03.012"
- Description: One of the challenges in electrochemical biosensor design is gaining a fundamental knowledge of the processes underlying immobilisation of the molecules onto the electrode surface. This is of particular importance in biocomposite sensors where concerns have arisen as to the nature of the interaction between the biological and synthetic molecules immobilised. We examined the use of the Quartz Crystal Microbalance with Dissipation (QCM-D) as a tool for fundamental analyses of a model sensor constructed by the immobilisation of cobalt(II) phthalocyanine (TCACoPc) and glucose oxidase (GOx) onto a gold-quartz electrode (electrode surface) for the enhanced detection of glucose. The model sensor was constructed in aqueous phase and covalently linked the gold surface to the TCACoPc, and the TCACoPc to the GOx, using the QCM-D. The aqueous metallophthalocyanine (MPc) formed a multi-layer over the surface of the electrode, which could be removed to leave a monolayer with a mass loading that compared favourably to the theoretical value expected. Analysis of frequency and dissipation plots indicated covalent attachment of glucose oxidase onto the metallophthalocyanine layer. The amount of GOx bound using the model system compared favourably to calculations derived from the maximal amperometric functioning of the electrochemical sensor (examined in previously-published literature, Mashazi, P.N., Ozoemena, K.I., Nyokong, T., 2006. Electrochim. Acta 52, 177–186), but not to theoretical values derived from dimensions of GOx as established by crystallography. The strength of the binding of the GOx film with the TCACoPc layer was tested by using 2% SDS as a denaturant/surfactant, and the GOx film was not found to be significantly affected by exposure to this. This paper thus showed that QCM-D can be used in order to model essential processes and interactions that dictate the functional parameters of a biosensor.
- Full Text:
- Date Issued: 2007
Cultural values and leadership styles of middle level managers in a private sector hospitals in the Eastern Cape
- Authors: Boguslavsky, Marianna
- Date: 2007
- Subjects: Hospitals, Proprietary -- South Africa -- Eastern Cape , Leadership -- South Africa -- Eastern Cape , Middle managers -- South Africa -- Eastern Cape , Corporate culture -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:10080 , http://hdl.handle.net/10948/478 , http://hdl.handle.net/10948/d1011927 , Hospitals, Proprietary -- South Africa -- Eastern Cape , Leadership -- South Africa -- Eastern Cape , Middle managers -- South Africa -- Eastern Cape , Corporate culture -- South Africa -- Eastern Cape
- Description: In recent years, South Africa has seen increasing cultural diversification with regard to the appointment of managers in private healthcare facilities. However, research conducted in this area remains extremely limited. The aim of the present study was to explore and describe cultural values and leadership styles of middle managers at a private sector hospital in the Eastern Cape. Hofstede’s (1980, a ) model of cultural values served as a theoretical framework to conceptualise this study. The study was qualitative in nature and made use of in-depth research interviews conducted with a diverse sample of middle managers. The researcher made use of homogeneous and convenience sampling and utilised five participants. The qualitative data was analysed using Tesch’s (1990, in De Vos, 2002) method of analysis. Results revealed that despite the differences in personal culture, most of the managers are similar in their leadership styles and are also affected by the organizational culture. The results of the study contribute to a better understanding of the influence of cultural values and leadership styles in South Africa and will thereby benefit health institutions in their dealings with their modern day multi-cultural management staff.
- Full Text:
- Date Issued: 2007
- Authors: Boguslavsky, Marianna
- Date: 2007
- Subjects: Hospitals, Proprietary -- South Africa -- Eastern Cape , Leadership -- South Africa -- Eastern Cape , Middle managers -- South Africa -- Eastern Cape , Corporate culture -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:10080 , http://hdl.handle.net/10948/478 , http://hdl.handle.net/10948/d1011927 , Hospitals, Proprietary -- South Africa -- Eastern Cape , Leadership -- South Africa -- Eastern Cape , Middle managers -- South Africa -- Eastern Cape , Corporate culture -- South Africa -- Eastern Cape
- Description: In recent years, South Africa has seen increasing cultural diversification with regard to the appointment of managers in private healthcare facilities. However, research conducted in this area remains extremely limited. The aim of the present study was to explore and describe cultural values and leadership styles of middle managers at a private sector hospital in the Eastern Cape. Hofstede’s (1980, a ) model of cultural values served as a theoretical framework to conceptualise this study. The study was qualitative in nature and made use of in-depth research interviews conducted with a diverse sample of middle managers. The researcher made use of homogeneous and convenience sampling and utilised five participants. The qualitative data was analysed using Tesch’s (1990, in De Vos, 2002) method of analysis. Results revealed that despite the differences in personal culture, most of the managers are similar in their leadership styles and are also affected by the organizational culture. The results of the study contribute to a better understanding of the influence of cultural values and leadership styles in South Africa and will thereby benefit health institutions in their dealings with their modern day multi-cultural management staff.
- Full Text:
- Date Issued: 2007
Cytokine properties of CD23 on human Eosinophilic cells
- Authors: Ferreira, Lauren
- Date: 2007
- Subjects: Cytokines , CD23 antigen , Eosinophil
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10333 , http://hdl.handle.net/10948/503 , http://hdl.handle.net/10948/d1012001 , Cytokines , CD23 antigen , Eosinophil
- Description: CD23, the low affinity IgE receptor, is expressed by various cell types and has numerous functions depending on the form of the protein, its interaction with various ligands and the type of cell involved. CD23 is pivotal in the regulation of IgE, with the soluble form involved in up-regulation, while the membrane bound form is involved in the down-regulation. It is clear why it is believed to be a central molecule in allergic responses, and a therapeutic target for the treatment of allergic disease. In this study a recombinant form of the entire extracellular domain of the protein, exCD23, was produced by PCR cloning and expressed in E. coli. His•Tag™s were introduced onto the C-terminus and N-terminus, respectively, in order to simplify the purification procedure. After renaturation and purification, the recombinant exCD23 bound IgE, indicating its activity. From the IgE binding studies it was established that the position of the tag did not influence the binding. GST•Tagged™ exCD23 was also produced in an attempt to increase the solubility of the recombinant protein, but this proved unsuccessful. Butyrate differentiated EoL-1 cells were treated with the Nterminal His•Tagged™ exCD23, and the protein appeared to suppress the secretion of the constitutively expressed cytokines, especially IL-8 and IFN- , when compared to untreated cells. In addition, treatment of the EoL-1 cells with exCD23 had a significant proliferative effect, but could not induce differentiation of this cell line into mature eosinophilic-like cells.
- Full Text:
- Date Issued: 2007
- Authors: Ferreira, Lauren
- Date: 2007
- Subjects: Cytokines , CD23 antigen , Eosinophil
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10333 , http://hdl.handle.net/10948/503 , http://hdl.handle.net/10948/d1012001 , Cytokines , CD23 antigen , Eosinophil
- Description: CD23, the low affinity IgE receptor, is expressed by various cell types and has numerous functions depending on the form of the protein, its interaction with various ligands and the type of cell involved. CD23 is pivotal in the regulation of IgE, with the soluble form involved in up-regulation, while the membrane bound form is involved in the down-regulation. It is clear why it is believed to be a central molecule in allergic responses, and a therapeutic target for the treatment of allergic disease. In this study a recombinant form of the entire extracellular domain of the protein, exCD23, was produced by PCR cloning and expressed in E. coli. His•Tag™s were introduced onto the C-terminus and N-terminus, respectively, in order to simplify the purification procedure. After renaturation and purification, the recombinant exCD23 bound IgE, indicating its activity. From the IgE binding studies it was established that the position of the tag did not influence the binding. GST•Tagged™ exCD23 was also produced in an attempt to increase the solubility of the recombinant protein, but this proved unsuccessful. Butyrate differentiated EoL-1 cells were treated with the Nterminal His•Tagged™ exCD23, and the protein appeared to suppress the secretion of the constitutively expressed cytokines, especially IL-8 and IFN- , when compared to untreated cells. In addition, treatment of the EoL-1 cells with exCD23 had a significant proliferative effect, but could not induce differentiation of this cell line into mature eosinophilic-like cells.
- Full Text:
- Date Issued: 2007
Cytosolic and ER J-domains of mammalian and parasitic origin can functionally interact with DnaK
- Nicoll, W S, Botha, M, McNamara, Caryn, Schlange, M, Pesce, E R, Boshoff, Aileen, Ludewig, M H, Zimmerman, R, Cheetham, M E, Chapple, J P, Blatch, Gregory L
- Authors: Nicoll, W S , Botha, M , McNamara, Caryn , Schlange, M , Pesce, E R , Boshoff, Aileen , Ludewig, M H , Zimmerman, R , Cheetham, M E , Chapple, J P , Blatch, Gregory L
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6484 , http://hdl.handle.net/10962/d1006261 , http://www.sciencedirect.com/science/article/pii/S1357272506003268
- Description: Both prokaryotic and eukaryotic cells contain multiple heat shock protein 40 (Hsp40) and heat shock protein 70 (Hsp70) proteins, which cooperate as molecular chaperones to ensure fidelity at all stages of protein biogenesis. The Hsp40 signature domain, the J-domain, is required for binding of an Hsp40 to a partner Hsp70, and may also play a role in the specificity of the association. Through the creation of chimeric Hsp40 proteins by the replacement of the J-domain of a prokaryotic Hsp40 (DnaJ), we have tested the functional equivalence of J-domains from a number of divergent Hsp40s of mammalian and parasitic origin (malarial Pfj1 and Pfj4, trypanosomal Tcj3, human ERj3, ERj5, and Hsj1, and murine ERj1). An in vivo functional assay was used to test the functionality of the chimeric proteins on the basis of their ability to reverse the thermosensitivity of a dnaJ cbpA mutant Escherichia coli strain (OD259). The Hsp40 chimeras containing J-domains originating from soluble (cytosolic or endoplasmic reticulum (ER)-lumenal) Hsp40s were able to reverse the thermosensitivity of E. coli OD259. In all cases, modified derivatives of these chimeric proteins containing an His to Gln substitution in the HPD motif of the J-domain were unable to reverse the thermosensitivity of E. coli OD259. This suggested that these J-domains exerted their in vivo functionality through a specific interaction with E. coli Hsp70, DnaK. Interestingly, a Hsp40 chimera containing the J-domain of ERj1, an integral membrane-bound ER Hsp40, was unable to reverse the thermosensitivity of E. coli OD259, suggesting that this J-domain was unable to functionally interact with DnaK. Substitutions of conserved amino acid residues and motifs were made in all four helices (I-IV) and the loop regions of the J-domains, and the modified chimeric Hsp40s were tested for functionality using the in vivo assay. Substitution of a highly conserved basic residue in helix II of the J-domain was found to disrupt in vivo functionality for all the J-domains tested. We propose that helix II and the HPD motif of the J-domain represent the fundamental elements of a binding surface required for the interaction of Hsp40s with Hsp70s, and that this surface has been conserved in mammalian, parasitic and bacterial systems.
- Full Text:
- Date Issued: 2007
- Authors: Nicoll, W S , Botha, M , McNamara, Caryn , Schlange, M , Pesce, E R , Boshoff, Aileen , Ludewig, M H , Zimmerman, R , Cheetham, M E , Chapple, J P , Blatch, Gregory L
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6484 , http://hdl.handle.net/10962/d1006261 , http://www.sciencedirect.com/science/article/pii/S1357272506003268
- Description: Both prokaryotic and eukaryotic cells contain multiple heat shock protein 40 (Hsp40) and heat shock protein 70 (Hsp70) proteins, which cooperate as molecular chaperones to ensure fidelity at all stages of protein biogenesis. The Hsp40 signature domain, the J-domain, is required for binding of an Hsp40 to a partner Hsp70, and may also play a role in the specificity of the association. Through the creation of chimeric Hsp40 proteins by the replacement of the J-domain of a prokaryotic Hsp40 (DnaJ), we have tested the functional equivalence of J-domains from a number of divergent Hsp40s of mammalian and parasitic origin (malarial Pfj1 and Pfj4, trypanosomal Tcj3, human ERj3, ERj5, and Hsj1, and murine ERj1). An in vivo functional assay was used to test the functionality of the chimeric proteins on the basis of their ability to reverse the thermosensitivity of a dnaJ cbpA mutant Escherichia coli strain (OD259). The Hsp40 chimeras containing J-domains originating from soluble (cytosolic or endoplasmic reticulum (ER)-lumenal) Hsp40s were able to reverse the thermosensitivity of E. coli OD259. In all cases, modified derivatives of these chimeric proteins containing an His to Gln substitution in the HPD motif of the J-domain were unable to reverse the thermosensitivity of E. coli OD259. This suggested that these J-domains exerted their in vivo functionality through a specific interaction with E. coli Hsp70, DnaK. Interestingly, a Hsp40 chimera containing the J-domain of ERj1, an integral membrane-bound ER Hsp40, was unable to reverse the thermosensitivity of E. coli OD259, suggesting that this J-domain was unable to functionally interact with DnaK. Substitutions of conserved amino acid residues and motifs were made in all four helices (I-IV) and the loop regions of the J-domains, and the modified chimeric Hsp40s were tested for functionality using the in vivo assay. Substitution of a highly conserved basic residue in helix II of the J-domain was found to disrupt in vivo functionality for all the J-domains tested. We propose that helix II and the HPD motif of the J-domain represent the fundamental elements of a binding surface required for the interaction of Hsp40s with Hsp70s, and that this surface has been conserved in mammalian, parasitic and bacterial systems.
- Full Text:
- Date Issued: 2007
D.H. Lawrence around the world: South African perspectives, (Eds.) Jim Phelps and Nigel Bell : book review
- Authors: Van Wyk Smith, Malvern
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6121 , http://hdl.handle.net/10962/d1004702
- Description: The book as a whole provides a scholarly overview of the central position held by the works and ideas of the English writer D. H. Lawrence in the curricula, teaching philosophies and world views of South African university English Departments in the early latter half of the twentieth century. If this suggests something of a resurrectionary enterprise - the informing spirit of the collection, Christina van Heyningen, died some decades ago - it is also true that the names of contributors read like a roll call of those South African and immigrant British academics who from the 1950s to the 1970s made some of our English Departments notable leaders in their field. Essays, old and new, have been carefully chosen and juxtaposed to reveal how and why the teaching of internationally significant literature (in this case the writings of D. H. Lawrence) was in those years deemed to form an essential part of the training of a maturing critical faculty with which to confront not just English literature and cognate academic subjects, but the complex world of adult human experience itself.
- Full Text:
- Date Issued: 2007
- Authors: Van Wyk Smith, Malvern
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6121 , http://hdl.handle.net/10962/d1004702
- Description: The book as a whole provides a scholarly overview of the central position held by the works and ideas of the English writer D. H. Lawrence in the curricula, teaching philosophies and world views of South African university English Departments in the early latter half of the twentieth century. If this suggests something of a resurrectionary enterprise - the informing spirit of the collection, Christina van Heyningen, died some decades ago - it is also true that the names of contributors read like a roll call of those South African and immigrant British academics who from the 1950s to the 1970s made some of our English Departments notable leaders in their field. Essays, old and new, have been carefully chosen and juxtaposed to reveal how and why the teaching of internationally significant literature (in this case the writings of D. H. Lawrence) was in those years deemed to form an essential part of the training of a maturing critical faculty with which to confront not just English literature and cognate academic subjects, but the complex world of adult human experience itself.
- Full Text:
- Date Issued: 2007
Department of Ichthyology and Fisheries Science: research report series 19
- Authors: Jones, C L W , Pattrick, P
- Date: 2007
- Language: English
- Type: text , Book
- Identifier: vital:7161 , http://hdl.handle.net/10962/d1011935
- Full Text:
- Date Issued: 2007
- Authors: Jones, C L W , Pattrick, P
- Date: 2007
- Language: English
- Type: text , Book
- Identifier: vital:7161 , http://hdl.handle.net/10962/d1011935
- Full Text:
- Date Issued: 2007
Depressive disorders and chronic comorbid disease states: a pharmacoepidemiological evaluation
- Authors: Kritiotis, Lia Costas
- Date: 2007
- Subjects: Depression, Mental , Child psychopathology , Adolescent psychopathology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10151 , http://hdl.handle.net/10948/653 , Depression, Mental , Child psychopathology , Adolescent psychopathology
- Description: The treatment of Depressive Disorders in patients with chronic comorbid disease states warrants careful consideration of the risk-benefit ratio pertaining to the pharmacokinetic and pharmacodynamic characteristics of the antidepressant being considered, against the physiological susceptibilities of the patient; potential drug-drug interactions and depressive symptoms. The primary aim of this study was to investigate the relationship between Depressive Disorders and the most frequently diagnosed chronic comorbid disease states in a depressed South African study population; and to comment on the appropriateness of antidepressants prescribed to these patients. This retrospective drug utilisation study consisted of two parts: the first part focused on the prevalence of the most frequently diagnosed chronic comorbidities in a depressed South African population (N = 21 171). The three most prevalent chronic comorbid disease states were Hypertension (52.87 percent), Lipid Disorders (20.40 percent) and Arthritis (16.70 percent). The second part of the study included an assessment of the antidepressants prescribed to depressed patients in 2004 (N = 6 150). Emphasis was placed on the suitability of antidepressants selected for depressed adult patients (18 years of age and older) with comorbid Hypertension, Lipid Disorders or Arthritis. SSRIs were prescribed most frequently to the depressed patients during 2004 (59.67 percent). SSRIs are the suggested first-line treatments for depressed patients with multiple chronic comorbid disease states. However, of the SSRIs, fluoxetine has the least favourable pharmacokinetic profile and was found to be the antidepressant prescribed most often. Amitriptyline, which was the TCA prescribed most frequently, produces the greatest degree of anticholinergic, sedative and hypotensive effects, relative to other agents in the same antidepressant class. Thus, it is not recommended as a first-line antidepressant, especially in depressed patients with comorbidities. This study identifies potential areas of intervention regarding antidepressant prescribing in depressed individuals with chronic comorbid disease states and offers recommendations to promote the selection of optimal, individualised drug treatment strategies for these patients.
- Full Text:
- Date Issued: 2007
- Authors: Kritiotis, Lia Costas
- Date: 2007
- Subjects: Depression, Mental , Child psychopathology , Adolescent psychopathology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10151 , http://hdl.handle.net/10948/653 , Depression, Mental , Child psychopathology , Adolescent psychopathology
- Description: The treatment of Depressive Disorders in patients with chronic comorbid disease states warrants careful consideration of the risk-benefit ratio pertaining to the pharmacokinetic and pharmacodynamic characteristics of the antidepressant being considered, against the physiological susceptibilities of the patient; potential drug-drug interactions and depressive symptoms. The primary aim of this study was to investigate the relationship between Depressive Disorders and the most frequently diagnosed chronic comorbid disease states in a depressed South African study population; and to comment on the appropriateness of antidepressants prescribed to these patients. This retrospective drug utilisation study consisted of two parts: the first part focused on the prevalence of the most frequently diagnosed chronic comorbidities in a depressed South African population (N = 21 171). The three most prevalent chronic comorbid disease states were Hypertension (52.87 percent), Lipid Disorders (20.40 percent) and Arthritis (16.70 percent). The second part of the study included an assessment of the antidepressants prescribed to depressed patients in 2004 (N = 6 150). Emphasis was placed on the suitability of antidepressants selected for depressed adult patients (18 years of age and older) with comorbid Hypertension, Lipid Disorders or Arthritis. SSRIs were prescribed most frequently to the depressed patients during 2004 (59.67 percent). SSRIs are the suggested first-line treatments for depressed patients with multiple chronic comorbid disease states. However, of the SSRIs, fluoxetine has the least favourable pharmacokinetic profile and was found to be the antidepressant prescribed most often. Amitriptyline, which was the TCA prescribed most frequently, produces the greatest degree of anticholinergic, sedative and hypotensive effects, relative to other agents in the same antidepressant class. Thus, it is not recommended as a first-line antidepressant, especially in depressed patients with comorbidities. This study identifies potential areas of intervention regarding antidepressant prescribing in depressed individuals with chronic comorbid disease states and offers recommendations to promote the selection of optimal, individualised drug treatment strategies for these patients.
- Full Text:
- Date Issued: 2007
Design and implementation of a network revenue management architecture for marginalised communities
- Authors: Tarwireyi, Paul
- Date: 2007
- Subjects: Community development -- South Africa -- Eastern Cape , Computer network architectures -- South Africa -- Design and construction , Computer network protocols -- South Africa -- Eastern Cape -- Design and construction , Revenue management , Computer networks -- Social aspects
- Language: English
- Type: Thesis , Masters , MSc (Computer Science)
- Identifier: vital:11374 , http://hdl.handle.net/10353/72 , Community development -- South Africa -- Eastern Cape , Computer network architectures -- South Africa -- Design and construction , Computer network protocols -- South Africa -- Eastern Cape -- Design and construction , Revenue management , Computer networks -- Social aspects
- Description: Rural Internet connectivity projects aimed at bridging the digital divide have mushroomed across many developing countries. Most of the projects are deployed as community centred projects. In most of the cases the initial deployment of these projects is funded by governments, multilateral institutions and non-governmental organizations. After the initial deployment, financial sustainability remains one of the greatest challenges facing these projects. In the light of this, externally funded ICT4D interventions should just be used for “bootstrapping” purposes. The communities should be “groomed” to take care of and sustain these projects, eliminating as soon as possible a dependency on external funding. This master thesis presents the design and the implementation of a generic architecture for the management of the costs associated with running a computer network connected to the Internet, The proposed system, called the Network Revenue Management System, enables a network to generate revenue, by charging users for the utilization of network resources. The novelty of the system resides in its flexibility and adaptability, which allow the exploration of both conventional and non-conventional billing options, via the use of suitable ‘adapters’. The final goal of the exploration made possible by this system is the establishment of what is regarded as equitable charging in rural, marginalized communities - such as the community in Dwesa, South Africa.
- Full Text:
- Date Issued: 2007
- Authors: Tarwireyi, Paul
- Date: 2007
- Subjects: Community development -- South Africa -- Eastern Cape , Computer network architectures -- South Africa -- Design and construction , Computer network protocols -- South Africa -- Eastern Cape -- Design and construction , Revenue management , Computer networks -- Social aspects
- Language: English
- Type: Thesis , Masters , MSc (Computer Science)
- Identifier: vital:11374 , http://hdl.handle.net/10353/72 , Community development -- South Africa -- Eastern Cape , Computer network architectures -- South Africa -- Design and construction , Computer network protocols -- South Africa -- Eastern Cape -- Design and construction , Revenue management , Computer networks -- Social aspects
- Description: Rural Internet connectivity projects aimed at bridging the digital divide have mushroomed across many developing countries. Most of the projects are deployed as community centred projects. In most of the cases the initial deployment of these projects is funded by governments, multilateral institutions and non-governmental organizations. After the initial deployment, financial sustainability remains one of the greatest challenges facing these projects. In the light of this, externally funded ICT4D interventions should just be used for “bootstrapping” purposes. The communities should be “groomed” to take care of and sustain these projects, eliminating as soon as possible a dependency on external funding. This master thesis presents the design and the implementation of a generic architecture for the management of the costs associated with running a computer network connected to the Internet, The proposed system, called the Network Revenue Management System, enables a network to generate revenue, by charging users for the utilization of network resources. The novelty of the system resides in its flexibility and adaptability, which allow the exploration of both conventional and non-conventional billing options, via the use of suitable ‘adapters’. The final goal of the exploration made possible by this system is the establishment of what is regarded as equitable charging in rural, marginalized communities - such as the community in Dwesa, South Africa.
- Full Text:
- Date Issued: 2007
Determination of the botanical composition of black rhinoceros (Diceros bicornis) dung using the rbcL gene as a molecular marker, and analysis of antioxidant and phenolic content of its browse
- Authors: Bulani, Siyavuya Ishmael
- Date: 2007 , 2013-06-25
- Subjects: Black rhinoceros -- Food , Black rhinoceros -- South Africa -- Eastern Cape , Browse (Animal food) -- Analysis -- South Africa -- Eastern Cape , Plant ecology -- South Africa -- Eastern Cape , Genetic markers , Black rhinoceros -- Manure -- Analysis , Phenols , Antioxidants
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4070 , http://hdl.handle.net/10962/d1006468 , Black rhinoceros -- Food , Black rhinoceros -- South Africa -- Eastern Cape , Browse (Animal food) -- Analysis -- South Africa -- Eastern Cape , Plant ecology -- South Africa -- Eastern Cape , Genetic markers , Black rhinoceros -- Manure -- Analysis , Phenols , Antioxidants
- Description: The black rhinoceros remains one of the world's extremely endangered species despite a variety of policies to protect it. The black rhinoceros population at the Great Fish River Reserve (GFRR) in the Eastern Cape in South Africa has increased steadily since their re-introduction in 1986. This megaherbivore is a browser, with a diet obtained largely from the short and medium succulent thicket of the GFRR. Knowledge of the preferential diet of the black rhinoceros on the reserve is an important factor for the effective management of the land and the herbivores that compete for its resources. The dietary preferences of the black rhinoceros at the reserve have been established using backtracking methods. In this study the rbcL gene was used to establish an rbcL gene database of the plants from the GFRR and determine the botanical composition of the black rhinoceros dung from the GFRR. Due to the limited number of rbcL gene plant sequences from the GFRR deposited in the GenBank database, 18 plant species from the GFRR were sequenced. Sequence analyses between the partial rbcL gene sequences generated were able to distinguish between plants down to species level. Plant species from the family Euphorbiaceae and Fabaceae showed sequence variation at intra-specific level compared to those of Tiliaceae which were more conserved. The generated rbcL gene sequences from seasonal dung samples were compared to the rbcL gene sequenced from 18 plant species obtained from the GFRR and those from the GenBank database. A wide range of plant species were identified from the dung samples. There were no major differences in botanical composition between the dung samples, except that Grewia spp. were found to dominate in almost all seasons. The results obtained on the free radical scavenging activity of the extracts against 2,2-Diphenyl-l-picrylhydrazyl (DPPH) increased in the order of methanol > ethyl acetate > chloroform. The DPPH free radical scavenging activity of the methanol plant extracts increased in the order Brachylaena elliptica > Plumbago auriculata > Grewia robusta > Azima tetracantha. Methanol extracts on the TLC plate sprayed with Fe³⁺-2,4,6-Tri-2-pyridyl-s-triazine (TPTZ) showed that the compounds present in the extracts react differently to ferric ion, with most compounds unable to reduce ferric ion. Furthermore the methanol extracts were able to exhibit reduction potentials vs. Ag/AgCl at low concentrations. The compounds in the extracts were shown to be phenolic acids and flavonoid glycosides.
- Full Text:
- Date Issued: 2007
- Authors: Bulani, Siyavuya Ishmael
- Date: 2007 , 2013-06-25
- Subjects: Black rhinoceros -- Food , Black rhinoceros -- South Africa -- Eastern Cape , Browse (Animal food) -- Analysis -- South Africa -- Eastern Cape , Plant ecology -- South Africa -- Eastern Cape , Genetic markers , Black rhinoceros -- Manure -- Analysis , Phenols , Antioxidants
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4070 , http://hdl.handle.net/10962/d1006468 , Black rhinoceros -- Food , Black rhinoceros -- South Africa -- Eastern Cape , Browse (Animal food) -- Analysis -- South Africa -- Eastern Cape , Plant ecology -- South Africa -- Eastern Cape , Genetic markers , Black rhinoceros -- Manure -- Analysis , Phenols , Antioxidants
- Description: The black rhinoceros remains one of the world's extremely endangered species despite a variety of policies to protect it. The black rhinoceros population at the Great Fish River Reserve (GFRR) in the Eastern Cape in South Africa has increased steadily since their re-introduction in 1986. This megaherbivore is a browser, with a diet obtained largely from the short and medium succulent thicket of the GFRR. Knowledge of the preferential diet of the black rhinoceros on the reserve is an important factor for the effective management of the land and the herbivores that compete for its resources. The dietary preferences of the black rhinoceros at the reserve have been established using backtracking methods. In this study the rbcL gene was used to establish an rbcL gene database of the plants from the GFRR and determine the botanical composition of the black rhinoceros dung from the GFRR. Due to the limited number of rbcL gene plant sequences from the GFRR deposited in the GenBank database, 18 plant species from the GFRR were sequenced. Sequence analyses between the partial rbcL gene sequences generated were able to distinguish between plants down to species level. Plant species from the family Euphorbiaceae and Fabaceae showed sequence variation at intra-specific level compared to those of Tiliaceae which were more conserved. The generated rbcL gene sequences from seasonal dung samples were compared to the rbcL gene sequenced from 18 plant species obtained from the GFRR and those from the GenBank database. A wide range of plant species were identified from the dung samples. There were no major differences in botanical composition between the dung samples, except that Grewia spp. were found to dominate in almost all seasons. The results obtained on the free radical scavenging activity of the extracts against 2,2-Diphenyl-l-picrylhydrazyl (DPPH) increased in the order of methanol > ethyl acetate > chloroform. The DPPH free radical scavenging activity of the methanol plant extracts increased in the order Brachylaena elliptica > Plumbago auriculata > Grewia robusta > Azima tetracantha. Methanol extracts on the TLC plate sprayed with Fe³⁺-2,4,6-Tri-2-pyridyl-s-triazine (TPTZ) showed that the compounds present in the extracts react differently to ferric ion, with most compounds unable to reduce ferric ion. Furthermore the methanol extracts were able to exhibit reduction potentials vs. Ag/AgCl at low concentrations. The compounds in the extracts were shown to be phenolic acids and flavonoid glycosides.
- Full Text:
- Date Issued: 2007
Determining the daily spawning cycle of the chokka squid, Loligo reynaudii off the South African Coast
- Authors: Melo, Y , Sauer, Warwick H H
- Date: 2007
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124275 , vital:35588 , https://doi.10.1007/s11160-006-9034-6
- Description: The study investigated the duration and peak of the daily spawning cycle of the chokka squid Loligo reynaudii, and the possibility of estimating the spawning frequency by means of classification and grouping (by age) of postovulatory follicles. Post-ovulatory follicles were classified into three types: new, intermediate or old, based in part on the degree of resorption of the follicles determined from histological sections. Ovulation in this species appears to be a rapid process, seen by the occurrence of both mature oocytes and post-ovulatory follicles in partially spent ovaries. Results suggest that chokka squid present a diel timing of spawning, with successive periods of egg accumulation at night, interrupted by periods of active spawning during the day. The ovarian cycle for this species appears typical of serial spawners. During the spawning phase ovaries go through ripe, partially spent and recovering stages by undergoing a process of maturation, ovulation and redeveloping, where a new batch of advanced oocytes is recruited. The cycle typically appears to last between 24 and 36 h, and may depend on a number of factors such as environmental conditions and the presence of predators. The short-lived (about 14 h) nature of the post-ovulatory follicles precludes the calculation of the exact spawning interval and does not allow us to accurately predict the spawning frequency. Together with the degree of oviduct fullness they do however give a good indication of imminent or recent spawning.
- Full Text:
- Date Issued: 2007
- Authors: Melo, Y , Sauer, Warwick H H
- Date: 2007
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124275 , vital:35588 , https://doi.10.1007/s11160-006-9034-6
- Description: The study investigated the duration and peak of the daily spawning cycle of the chokka squid Loligo reynaudii, and the possibility of estimating the spawning frequency by means of classification and grouping (by age) of postovulatory follicles. Post-ovulatory follicles were classified into three types: new, intermediate or old, based in part on the degree of resorption of the follicles determined from histological sections. Ovulation in this species appears to be a rapid process, seen by the occurrence of both mature oocytes and post-ovulatory follicles in partially spent ovaries. Results suggest that chokka squid present a diel timing of spawning, with successive periods of egg accumulation at night, interrupted by periods of active spawning during the day. The ovarian cycle for this species appears typical of serial spawners. During the spawning phase ovaries go through ripe, partially spent and recovering stages by undergoing a process of maturation, ovulation and redeveloping, where a new batch of advanced oocytes is recruited. The cycle typically appears to last between 24 and 36 h, and may depend on a number of factors such as environmental conditions and the presence of predators. The short-lived (about 14 h) nature of the post-ovulatory follicles precludes the calculation of the exact spawning interval and does not allow us to accurately predict the spawning frequency. Together with the degree of oviduct fullness they do however give a good indication of imminent or recent spawning.
- Full Text:
- Date Issued: 2007
Development and assessment of an oxytocin parenteral dosage form prepared using pluronic ® F127
- Authors: Chaibva, Faith Anesu
- Date: 2007
- Subjects: Oxytocin -- Therapeutic use , Drugs -- Dosage forms , Pregnancy -- Complications -- Management
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3747 , http://hdl.handle.net/10962/d1003225 , Oxytocin -- Therapeutic use , Drugs -- Dosage forms , Pregnancy -- Complications -- Management
- Full Text:
- Date Issued: 2007
- Authors: Chaibva, Faith Anesu
- Date: 2007
- Subjects: Oxytocin -- Therapeutic use , Drugs -- Dosage forms , Pregnancy -- Complications -- Management
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3747 , http://hdl.handle.net/10962/d1003225 , Oxytocin -- Therapeutic use , Drugs -- Dosage forms , Pregnancy -- Complications -- Management
- Full Text:
- Date Issued: 2007
Development and in vitro evaluation of a clobetasol 17-propionate topical cream formulation
- Authors: Wa Kasongo, Kasongo
- Date: 2007
- Subjects: Adrenocortical hormones , Adrenocortical hormones -- Physiological effect , Drugs -- Testing , Drug development , Dermatopharmacology
- Language: English
- Type: Thesis , Masters , MPharm
- Identifier: vital:3799 , http://hdl.handle.net/10962/d1003277 , Adrenocortical hormones , Adrenocortical hormones -- Physiological effect , Drugs -- Testing , Drug development , Dermatopharmacology
- Description: One of the primary contributing factors to the escalating costs of health care is the high cost of innovator pharmaceutical products. As a consequence, health authorities in various countries and in particular in the developing world have identified generic prescribing and generic substitution as possible strategies to contain the escalating costs of health care provision. There is therefore a need for formulation scientists in developing countries to invest more time in the research and development of generic formulations. Clobetasol 17-propionate (CP) generic cream formulations containing 0.05% w/w of the drug were manufactured and characterized using in vitro testing. Formulation development studies were preceded by the development and validation of an RP-HPLC with UV detection for the quantitation and characterization of CP in innovator and generic cream formulations during formulation development and assessment studies. Furthermore the in vitro release ates of CP release from innovator and generic cream formulations were monitored using a validated in vitro release test method developed in these studies. The formulation of CP cream products was accomplished using a variety of commercially available mixed primary emulsifiers, such as Estol® 1474, Ritapro® 200, Emulcire® 61 WL and Gelot® 64. Successful formulations were selected based on their ability to remain physically stable immediately after manufacture and for 24 hours after storage at room temperature (22°C). Estol® 1474 was found to produce an unstable cream and was therefore not investigated further. The other three emulgents produced stable creams, but only the in vitro release profile of CP from a cream manufactured to contain Gelot® 64 was found to be statistically similar to that of the innovator formulation. Therefore the cream containing Gelot® 64 was selected as the most appropriate prototype generic cream formulation and was characterized in vitro in terms of CP content, viscosity, pH and in vitro release rate. Data generated from these studies were compared to those of the innovator product, Dermovate® cream, using statistical methods. The CP content, pH and in vitro release rate data of the CP formulation were similar to those of the innovator product, however the intrinsic viscosity of Dermovate® cream was almost three (3) times greater than the intrinsic viscosity of the test formulation developed using Gelot® 64. The CP cream formulation developed in these studies was stored for 4 weeks at 40 ± 2°C and 25 ± 5% RH in an incubator and the formulation was found to be stable. A formulation has been developed and assessed and found to be suitable for use as a topical semi-solid dosage form for CP.
- Full Text:
- Date Issued: 2007
- Authors: Wa Kasongo, Kasongo
- Date: 2007
- Subjects: Adrenocortical hormones , Adrenocortical hormones -- Physiological effect , Drugs -- Testing , Drug development , Dermatopharmacology
- Language: English
- Type: Thesis , Masters , MPharm
- Identifier: vital:3799 , http://hdl.handle.net/10962/d1003277 , Adrenocortical hormones , Adrenocortical hormones -- Physiological effect , Drugs -- Testing , Drug development , Dermatopharmacology
- Description: One of the primary contributing factors to the escalating costs of health care is the high cost of innovator pharmaceutical products. As a consequence, health authorities in various countries and in particular in the developing world have identified generic prescribing and generic substitution as possible strategies to contain the escalating costs of health care provision. There is therefore a need for formulation scientists in developing countries to invest more time in the research and development of generic formulations. Clobetasol 17-propionate (CP) generic cream formulations containing 0.05% w/w of the drug were manufactured and characterized using in vitro testing. Formulation development studies were preceded by the development and validation of an RP-HPLC with UV detection for the quantitation and characterization of CP in innovator and generic cream formulations during formulation development and assessment studies. Furthermore the in vitro release ates of CP release from innovator and generic cream formulations were monitored using a validated in vitro release test method developed in these studies. The formulation of CP cream products was accomplished using a variety of commercially available mixed primary emulsifiers, such as Estol® 1474, Ritapro® 200, Emulcire® 61 WL and Gelot® 64. Successful formulations were selected based on their ability to remain physically stable immediately after manufacture and for 24 hours after storage at room temperature (22°C). Estol® 1474 was found to produce an unstable cream and was therefore not investigated further. The other three emulgents produced stable creams, but only the in vitro release profile of CP from a cream manufactured to contain Gelot® 64 was found to be statistically similar to that of the innovator formulation. Therefore the cream containing Gelot® 64 was selected as the most appropriate prototype generic cream formulation and was characterized in vitro in terms of CP content, viscosity, pH and in vitro release rate. Data generated from these studies were compared to those of the innovator product, Dermovate® cream, using statistical methods. The CP content, pH and in vitro release rate data of the CP formulation were similar to those of the innovator product, however the intrinsic viscosity of Dermovate® cream was almost three (3) times greater than the intrinsic viscosity of the test formulation developed using Gelot® 64. The CP cream formulation developed in these studies was stored for 4 weeks at 40 ± 2°C and 25 ± 5% RH in an incubator and the formulation was found to be stable. A formulation has been developed and assessed and found to be suitable for use as a topical semi-solid dosage form for CP.
- Full Text:
- Date Issued: 2007
Development of a regional GPS-based ionospheric TEC model for South Africa
- Opperman, Ben D L, Cilliers, Pierre J, McKinnell, Lee-Anne, Haggard, Raymond
- Authors: Opperman, Ben D L , Cilliers, Pierre J , McKinnell, Lee-Anne , Haggard, Raymond
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6799 , http://hdl.handle.net/10962/d1003925
- Description: Advances in South African space physics research and related disciplines require better spatial and time resolution ionospheric information than was previously possible with the existing ionosonde network. A GPS-based, variable degree adjusted spherical harmonic (ASHA) model was developed for near real-time regional ionospheric total electron content (TEC) mapping over South Africa. Slant TEC values along oblique GPS signal paths are quantified from a network of GPS receivers and converted to vertical TEC by means of the single layer mapping function. The ASHA model coefficients and GPS differential biases are estimated from vertical TEC at the ionospheric pierce points and used to interpolate TEC at any location within the region of interest. Diurnal TEC variations with one minute time resolution and time-varying 2D regional TEC maps are constructed. In order to validate the ASHA method, simulations with an IRI ionosphere were performed, while the ASHA results from actual data were compared with two independent GPS-based methodologies and measured ionosonde data.
- Full Text:
- Date Issued: 2007
- Authors: Opperman, Ben D L , Cilliers, Pierre J , McKinnell, Lee-Anne , Haggard, Raymond
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6799 , http://hdl.handle.net/10962/d1003925
- Description: Advances in South African space physics research and related disciplines require better spatial and time resolution ionospheric information than was previously possible with the existing ionosonde network. A GPS-based, variable degree adjusted spherical harmonic (ASHA) model was developed for near real-time regional ionospheric total electron content (TEC) mapping over South Africa. Slant TEC values along oblique GPS signal paths are quantified from a network of GPS receivers and converted to vertical TEC by means of the single layer mapping function. The ASHA model coefficients and GPS differential biases are estimated from vertical TEC at the ionospheric pierce points and used to interpolate TEC at any location within the region of interest. Diurnal TEC variations with one minute time resolution and time-varying 2D regional TEC maps are constructed. In order to validate the ASHA method, simulations with an IRI ionosphere were performed, while the ASHA results from actual data were compared with two independent GPS-based methodologies and measured ionosonde data.
- Full Text:
- Date Issued: 2007
Development of a school environmental policy to enable active learning in the context of the National Curriculum Statement
- Authors: Mvula-Jamela, Lungiswa Gwen
- Date: 2007
- Subjects: Environmental policy -- Study and teaching (Primary) -- South Africa -- Grahamstown Environmental education -- Study and teaching (Primary) -- South Africa -- Grahamstown Environmental education -- Activity programs -- South Africa -- Grahamstown Environmental education -- South Africa -- Grahamstown -- Case studies Competency-based education -- South Africa -- Grahamstown Teacher participation in curriculum planning -- South Africa -- Grahamstown
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1958 , http://hdl.handle.net/10962/d1008376
- Description: The transformation processes occurring in the South African curriculum context has highlighted a need for improving ways of interpreting and implementing curriculum requirements, in ways that are relevant to the context of learners and their experiences. Outcomes Based Education (OBE) encourages teachers to develop learner centred and active learning approaches. In this research I explore the development of how a School Environmental Policy can contribute to active learning in the context of the National Curriculum Statement for Grades R-9 (NCS R-9). I employed a participatory action research approach in which I worked with other teachers in my school to develop a School Environmental Policy, and then implement associated lessons. In cycle 1 this research focused on the School Environmental Policy development processes. In cycle 2 the research focused on designing and implementing three Lesson Plans in Makana Public Primary School (in three phases). I used a range of data generation strategies such as observations, use of a reflective journal, semi-structured interviews, focus group discussions, a workshop, photographs and document analysis to generate data for the study. All participants collaboratively discussed and agreed upon the research , and the two teachers who developed the lessons with me also reflected on the process of Lesson Planning and active learning, but I was responsible for the final interpretation presented in this thesis. The research indicates that the School Environmental Policy led to the planning of active learning processes and that the School Environmental Policy and the active learn ing approach are consistent with OBE policy and philosophy. The study also indicates that the School Environmental Policy and the active learning approach strengthened the use of Learning Outcomes, but not necessarily Assessment Standards and that the active learning approach promoted enquiry in lessons. The research further indicates that the School Environmental Policy and active learning processes contributed to school improvement and work towards a healthy environment. The School Environmental Policy also encouraged educators to address school community environmental issues and build stronger links with parents. The study also led to a set of recommendations to improve the School Environmental Policy and active learning process in ways that address the NCS requirements for learning and assessment.
- Full Text:
- Date Issued: 2007
- Authors: Mvula-Jamela, Lungiswa Gwen
- Date: 2007
- Subjects: Environmental policy -- Study and teaching (Primary) -- South Africa -- Grahamstown Environmental education -- Study and teaching (Primary) -- South Africa -- Grahamstown Environmental education -- Activity programs -- South Africa -- Grahamstown Environmental education -- South Africa -- Grahamstown -- Case studies Competency-based education -- South Africa -- Grahamstown Teacher participation in curriculum planning -- South Africa -- Grahamstown
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1958 , http://hdl.handle.net/10962/d1008376
- Description: The transformation processes occurring in the South African curriculum context has highlighted a need for improving ways of interpreting and implementing curriculum requirements, in ways that are relevant to the context of learners and their experiences. Outcomes Based Education (OBE) encourages teachers to develop learner centred and active learning approaches. In this research I explore the development of how a School Environmental Policy can contribute to active learning in the context of the National Curriculum Statement for Grades R-9 (NCS R-9). I employed a participatory action research approach in which I worked with other teachers in my school to develop a School Environmental Policy, and then implement associated lessons. In cycle 1 this research focused on the School Environmental Policy development processes. In cycle 2 the research focused on designing and implementing three Lesson Plans in Makana Public Primary School (in three phases). I used a range of data generation strategies such as observations, use of a reflective journal, semi-structured interviews, focus group discussions, a workshop, photographs and document analysis to generate data for the study. All participants collaboratively discussed and agreed upon the research , and the two teachers who developed the lessons with me also reflected on the process of Lesson Planning and active learning, but I was responsible for the final interpretation presented in this thesis. The research indicates that the School Environmental Policy led to the planning of active learning processes and that the School Environmental Policy and the active learn ing approach are consistent with OBE policy and philosophy. The study also indicates that the School Environmental Policy and the active learning approach strengthened the use of Learning Outcomes, but not necessarily Assessment Standards and that the active learning approach promoted enquiry in lessons. The research further indicates that the School Environmental Policy and active learning processes contributed to school improvement and work towards a healthy environment. The School Environmental Policy also encouraged educators to address school community environmental issues and build stronger links with parents. The study also led to a set of recommendations to improve the School Environmental Policy and active learning process in ways that address the NCS requirements for learning and assessment.
- Full Text:
- Date Issued: 2007
Development of a web-based interface for a wireless sensor network monitoring system
- Authors: Gumbo, Sibukele
- Date: 2007
- Subjects: Wireless LAN , Sensor networks , Wireless communication systems , Web sites -- Design , User interfaces (Computer systems)
- Language: English
- Type: Thesis , Masters , MSc (Computer Science)
- Identifier: vital:11372 , http://hdl.handle.net/10353/68 , Wireless LAN , Sensor networks , Wireless communication systems , Web sites -- Design , User interfaces (Computer systems)
- Description: In the recent past, wireless sensor technology has undergone advancements in its autonomous data collecting aspects, and has become an area worth investigating in relation to structural monitoring applications. The system described in this thesis aims at acquiring, storing and displaying overhead transmission line related data collected from a wireless sensor network. Open source tools were used in its development and implementation. The inherent linearly aligned topology of transmission line monitoring devices is not without shortcomings; hence analysis of linear node placement, hardware and software components was carried out to determine the feasibility of the system. Their limited data processing capabilities has motivated the development of a post processing wireless sensor application in order to present any collected structural data in an understandable format.
- Full Text:
- Date Issued: 2007
- Authors: Gumbo, Sibukele
- Date: 2007
- Subjects: Wireless LAN , Sensor networks , Wireless communication systems , Web sites -- Design , User interfaces (Computer systems)
- Language: English
- Type: Thesis , Masters , MSc (Computer Science)
- Identifier: vital:11372 , http://hdl.handle.net/10353/68 , Wireless LAN , Sensor networks , Wireless communication systems , Web sites -- Design , User interfaces (Computer systems)
- Description: In the recent past, wireless sensor technology has undergone advancements in its autonomous data collecting aspects, and has become an area worth investigating in relation to structural monitoring applications. The system described in this thesis aims at acquiring, storing and displaying overhead transmission line related data collected from a wireless sensor network. Open source tools were used in its development and implementation. The inherent linearly aligned topology of transmission line monitoring devices is not without shortcomings; hence analysis of linear node placement, hardware and software components was carried out to determine the feasibility of the system. Their limited data processing capabilities has motivated the development of a post processing wireless sensor application in order to present any collected structural data in an understandable format.
- Full Text:
- Date Issued: 2007
Development of an antiretroviral solid dosage form using multivariate analysis
- Authors: Nqabeni, Luxolo
- Date: 2007
- Subjects: Analysis of variance , Experimental design , Multivariate analysis , Antiretroviral agents -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10145 , http://hdl.handle.net/10948/705 , Analysis of variance , Experimental design , Multivariate analysis , Antiretroviral agents -- South Africa
- Description: The aim of pharmaceutical development is to design a quality product and the manufacturing process to deliver the product in a reproducible manner. The development of a new and generic formulation is based on a large number of experiments. Statistics provides many tools for studying the conditions of formulations and processes and enables us to optimize the same while being able to minimize our experimentation. The purpose of this study was to apply experimental design methodology (DOE) and multivariate analysis to the development and optimization of tablet formulations containing 150 mg lamivudine manufactured by direct compression.
- Full Text:
- Date Issued: 2007
- Authors: Nqabeni, Luxolo
- Date: 2007
- Subjects: Analysis of variance , Experimental design , Multivariate analysis , Antiretroviral agents -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10145 , http://hdl.handle.net/10948/705 , Analysis of variance , Experimental design , Multivariate analysis , Antiretroviral agents -- South Africa
- Description: The aim of pharmaceutical development is to design a quality product and the manufacturing process to deliver the product in a reproducible manner. The development of a new and generic formulation is based on a large number of experiments. Statistics provides many tools for studying the conditions of formulations and processes and enables us to optimize the same while being able to minimize our experimentation. The purpose of this study was to apply experimental design methodology (DOE) and multivariate analysis to the development and optimization of tablet formulations containing 150 mg lamivudine manufactured by direct compression.
- Full Text:
- Date Issued: 2007
Development of an in-situ ß-D-Glucuronidase diagnostic moraxella-based biosensor for potential application in the monitoring of water polluted by faecal material in South Africa
- Authors: Togo, Chamunorwa Aloius
- Date: 2007
- Subjects: Water quality management -- South Africa Water quality bioassay -- South Africa Sewage sludge -- South Africa -- Management Water -- Purification -- Biological treatment -- South Africa Biosensors
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3947 , http://hdl.handle.net/10962/d1004006
- Description: The prevention of outbreaks of waterborne diseases remains a major challenge to public health service providers globally. One of the major obstacles in this effort is the unavailability of on-line and real-time methods for rapid monitoring of faecal pollution to facilitate early warning of contamination of drinking water. The main objective of this study was to develop a β-glucuronidase (GUD)-based method that could be used for the on-line and real-time monitoring of microbial water quality. GUD is a marker enzyme for the faecal indicator bacteria Escherichia coli. This enzyme breaks down the synthetic substrate p-nitrophenyl-β-D-glucuronide (PNPG) to D-glucuronic acid and p-nitrophenol (PNP), which turns yellow under alkaline pH. The enzymatically produced PNP was used to detect GUD activity. In situ GUD assays were performed using running and stagnant water samples from the Bloukrans River, Grahamstown, South Africa. The physico-chemical properties of environmental GUD were determined, after which a liquid bioprobe and a microbial biosensor modified with Moraxella 1A species for the detection of the enzyme activity were developed. In order to determine the reliability and sensitivity of these methods, regression analyses for each method versus E. coli colony forming units (CFU) were performed. The storage stabilities of the bioprobe and biosensor were also investigated. The physico-chemical properties of in situ GUD were different from those of its commercially available counterpart. The temperature optimum for the former was between 35 and 40 °C while for the latter it was 45 °C. Commercial (reference) GUD had a pH optimum of 8.0 while the environmental counterpart exhibited a broad pH optimum of between pH 5.0 and 8.0. The liquid bioprobe had a limit of detection (LOD) of GUD activity equivalent to 2 CFU/100 ml and a detection time of 24 h. The method was less labour intensive and costly than the culturing method. The liquid bioprobe was stable for at least four weeks at room temperature (20 ± 2 °C). The biosensor was prepared by modifying a glassy carbon electrode with PNP degrading Moraxella 1A cells. The biosensor was 100 times more sensitive and rapid (5-20 min) than the spectrophotometric method (24 h), and was also able to detect GUD activity of viable but non-culturable cells. Thus it was more sensitive than the culturing method. Furthermore, the biosensor was selective and costeffective. The possibility of using a Pseudomonas putida JS444 biosensor was also investigated, but it was not as sensitive and selective as the Moraxella 1A biosensor. The Moraxella biosensor, therefore, offered the best option for on-line and real-time microbial water quality monitoring in South African river waters and drinking water supplies.
- Full Text:
- Date Issued: 2007
- Authors: Togo, Chamunorwa Aloius
- Date: 2007
- Subjects: Water quality management -- South Africa Water quality bioassay -- South Africa Sewage sludge -- South Africa -- Management Water -- Purification -- Biological treatment -- South Africa Biosensors
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3947 , http://hdl.handle.net/10962/d1004006
- Description: The prevention of outbreaks of waterborne diseases remains a major challenge to public health service providers globally. One of the major obstacles in this effort is the unavailability of on-line and real-time methods for rapid monitoring of faecal pollution to facilitate early warning of contamination of drinking water. The main objective of this study was to develop a β-glucuronidase (GUD)-based method that could be used for the on-line and real-time monitoring of microbial water quality. GUD is a marker enzyme for the faecal indicator bacteria Escherichia coli. This enzyme breaks down the synthetic substrate p-nitrophenyl-β-D-glucuronide (PNPG) to D-glucuronic acid and p-nitrophenol (PNP), which turns yellow under alkaline pH. The enzymatically produced PNP was used to detect GUD activity. In situ GUD assays were performed using running and stagnant water samples from the Bloukrans River, Grahamstown, South Africa. The physico-chemical properties of environmental GUD were determined, after which a liquid bioprobe and a microbial biosensor modified with Moraxella 1A species for the detection of the enzyme activity were developed. In order to determine the reliability and sensitivity of these methods, regression analyses for each method versus E. coli colony forming units (CFU) were performed. The storage stabilities of the bioprobe and biosensor were also investigated. The physico-chemical properties of in situ GUD were different from those of its commercially available counterpart. The temperature optimum for the former was between 35 and 40 °C while for the latter it was 45 °C. Commercial (reference) GUD had a pH optimum of 8.0 while the environmental counterpart exhibited a broad pH optimum of between pH 5.0 and 8.0. The liquid bioprobe had a limit of detection (LOD) of GUD activity equivalent to 2 CFU/100 ml and a detection time of 24 h. The method was less labour intensive and costly than the culturing method. The liquid bioprobe was stable for at least four weeks at room temperature (20 ± 2 °C). The biosensor was prepared by modifying a glassy carbon electrode with PNP degrading Moraxella 1A cells. The biosensor was 100 times more sensitive and rapid (5-20 min) than the spectrophotometric method (24 h), and was also able to detect GUD activity of viable but non-culturable cells. Thus it was more sensitive than the culturing method. Furthermore, the biosensor was selective and costeffective. The possibility of using a Pseudomonas putida JS444 biosensor was also investigated, but it was not as sensitive and selective as the Moraxella 1A biosensor. The Moraxella biosensor, therefore, offered the best option for on-line and real-time microbial water quality monitoring in South African river waters and drinking water supplies.
- Full Text:
- Date Issued: 2007
Development of written information for antiretroviral therapy: comprehension in a Tanzanian population
- Mwingira, Betty, Dowse, Roslind
- Authors: Mwingira, Betty , Dowse, Roslind
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6404 , http://hdl.handle.net/10962/d1006477
- Description: Objective To design and develop a simple, easily readable patient information leaflet (PIL) for a commonly used antiretroviral (ARV) regimen and to evaluate its readability and acceptability in a Tanzanian population. Method A PIL incorporating simple text and pictograms was designed for the antiretroviral regimen of stavudine, lamivudine and efavirenz. The PIL was designed according to established good design guidelines, modified during a multi-stage iterative testing process and piloted in a South African Xhosa population. The PIL was made available in both English and Kiswahili. Sixty Tanzanian participants who were not taking ARVs were interviewed. They were asked to read the PIL in the language of their choice and were then asked a series of two-part questions; the first part required participants to locate the information in the PIL, after which they were asked to explain the information in their own words. Acceptability was assessed through close-ended questions and open-ended feedback. The influence of selected patient characteristics on comprehension of the PIL was investigated using one-way ANOVA and t-tests for independent samples with a significance level set at 0.05. Main outcome measure Comprehension of the written information in an overall percentage understanding. Results The overall average percentage comprehension of the PIL was 95%. The target set by the EC guideline that at least 80% of participants correctly locate and understand the information was achieved for 19 of the 20 questions. Five of the six instructions illustrated by pictograms were correctly understood by all participants. The only patient characteristics significantly associated with comprehension were educational level and self-reported ease of reading the PIL. Acceptability of the PIL was high and positive comments were associated with simplicity, good design, easy readability and user-friendliness, the latter enhanced by the inclusion of pictograms. Conclusion The PIL designed for this study was shown to be effective in communicating information about ARVs. Patient characteristics must be taken into account when developing written information, and the final document must be tested for comprehension in the target population.
- Full Text:
- Date Issued: 2007
- Authors: Mwingira, Betty , Dowse, Roslind
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6404 , http://hdl.handle.net/10962/d1006477
- Description: Objective To design and develop a simple, easily readable patient information leaflet (PIL) for a commonly used antiretroviral (ARV) regimen and to evaluate its readability and acceptability in a Tanzanian population. Method A PIL incorporating simple text and pictograms was designed for the antiretroviral regimen of stavudine, lamivudine and efavirenz. The PIL was designed according to established good design guidelines, modified during a multi-stage iterative testing process and piloted in a South African Xhosa population. The PIL was made available in both English and Kiswahili. Sixty Tanzanian participants who were not taking ARVs were interviewed. They were asked to read the PIL in the language of their choice and were then asked a series of two-part questions; the first part required participants to locate the information in the PIL, after which they were asked to explain the information in their own words. Acceptability was assessed through close-ended questions and open-ended feedback. The influence of selected patient characteristics on comprehension of the PIL was investigated using one-way ANOVA and t-tests for independent samples with a significance level set at 0.05. Main outcome measure Comprehension of the written information in an overall percentage understanding. Results The overall average percentage comprehension of the PIL was 95%. The target set by the EC guideline that at least 80% of participants correctly locate and understand the information was achieved for 19 of the 20 questions. Five of the six instructions illustrated by pictograms were correctly understood by all participants. The only patient characteristics significantly associated with comprehension were educational level and self-reported ease of reading the PIL. Acceptability of the PIL was high and positive comments were associated with simplicity, good design, easy readability and user-friendliness, the latter enhanced by the inclusion of pictograms. Conclusion The PIL designed for this study was shown to be effective in communicating information about ARVs. Patient characteristics must be taken into account when developing written information, and the final document must be tested for comprehension in the target population.
- Full Text:
- Date Issued: 2007
Die bestuur van die geintegreerde gehaltebestuurstelsel
- Authors: James, Raymond Oscar
- Date: 2007
- Subjects: Total quality management -- South Africa , Quality assurance -- South Africa
- Language: Afrikaans
- Type: Thesis , Masters , MEd
- Identifier: vital:9540 , http://hdl.handle.net/10948/682 , Total quality management -- South Africa , Quality assurance -- South Africa
- Description: Die doel van hierdie studie was om te kyk hoe effektief die Geïntegreerde Gehaltebestuurstelsel (GGBS), en wel die taksering van opvoeders, bestuur kan word om positiewe resultate by skole te bereik. Die studie is gedoen binne die Interpretivistiese benadering. Data-invordering is gedoen deur middel van vraelyste, observasie en onderhoude. Die studie het getoon dat opvoeders onseker was, juis omdat die Onderwysdepartement nie die nodige leiding gegee en die nodige hulpbronne gehad het nie. Die afgelope twee jaar ( 2006 en 2007 ) egter het die Departement skouer aan die wiel gesit en hulp aan skole verleen, hetsy deur die beskikbaarstelling van die nodige vorms, of die aanstel van ‘n koördineerder om hulp aan skole te verskaf. Die belangrikste uitkomste van die studie was die besef dat opvoeders se vrese en aannames aangespreek moet word om ‘n gehaltebestuurstelsel effektief te maak. Slypskole moet gehou word om hulp en bystand aan die getakseerdes te verleen. Die bestuurspan van die skool moet ook indiensopleiding ondergaan, sodat hulle presies kan weet wat van hulle verwag word. Op hierdie manier word onsekerhede uit die weg geruim, want onsekerheid was die grootste probleem waarmee opvoeders te kampe gehad het in die implimentering van die GGBS.
- Full Text:
- Date Issued: 2007
- Authors: James, Raymond Oscar
- Date: 2007
- Subjects: Total quality management -- South Africa , Quality assurance -- South Africa
- Language: Afrikaans
- Type: Thesis , Masters , MEd
- Identifier: vital:9540 , http://hdl.handle.net/10948/682 , Total quality management -- South Africa , Quality assurance -- South Africa
- Description: Die doel van hierdie studie was om te kyk hoe effektief die Geïntegreerde Gehaltebestuurstelsel (GGBS), en wel die taksering van opvoeders, bestuur kan word om positiewe resultate by skole te bereik. Die studie is gedoen binne die Interpretivistiese benadering. Data-invordering is gedoen deur middel van vraelyste, observasie en onderhoude. Die studie het getoon dat opvoeders onseker was, juis omdat die Onderwysdepartement nie die nodige leiding gegee en die nodige hulpbronne gehad het nie. Die afgelope twee jaar ( 2006 en 2007 ) egter het die Departement skouer aan die wiel gesit en hulp aan skole verleen, hetsy deur die beskikbaarstelling van die nodige vorms, of die aanstel van ‘n koördineerder om hulp aan skole te verskaf. Die belangrikste uitkomste van die studie was die besef dat opvoeders se vrese en aannames aangespreek moet word om ‘n gehaltebestuurstelsel effektief te maak. Slypskole moet gehou word om hulp en bystand aan die getakseerdes te verleen. Die bestuurspan van die skool moet ook indiensopleiding ondergaan, sodat hulle presies kan weet wat van hulle verwag word. Op hierdie manier word onsekerhede uit die weg geruim, want onsekerheid was die grootste probleem waarmee opvoeders te kampe gehad het in die implimentering van die GGBS.
- Full Text:
- Date Issued: 2007
Die verbetering van dissipline as 'n sleutelbestuurstaak in 'n skool
- Authors: September, Willie Jeffrie
- Date: 2007
- Subjects: Classroom management -- South Africa , School discipline -- South Africa , School management teams
- Language: Afrikaans
- Type: Thesis , Masters , MEd
- Identifier: vital:9542 , http://hdl.handle.net/10948/679 , Classroom management -- South Africa , School discipline -- South Africa , School management teams
- Description: Die doel van hierdie studie is om die dissiplinêre probleme in skole soos dit in die Oudtshoorn-omgewing voorkom, te identifiseer en aan te spreek. Dit word gedoen deur te let op: • die skoolklimaat wat by 'n skool heers en die uitwerking van die skoolklimaat op die dissipline van`n skool. • die dissiplinêre probleme wat met skooldissipline in skole ervaar word. • die oorsake van skooldissipline en in watter mate die omgewing waarin die skool geleë is 'n invloed op skooldissipline het en • om oplossings vir dissiplinêre probleme soos vasgestel aan die hand te doen. Die studie poog om deur kwalitatiewe navorsingsmetodes vas te stel hoe prinsipale, opvoeders en leerders die huidige dissiplinêre situasie in skole ervaar. Dit poog dus om eerstehandse kennis te verkry van hul denke, gevoelens en gedagtes en hoe hierdie fenomeen hulle beïnvloed. Die studie kyk ook in watter mate skoolklimaat op die breë spektrum van skooldissipline 'n invloed het, en hoe die verbetering van skooldissipline `n sleutelbestuurstaak in 'n skool is. Die belangrikste bevindinge van die studie is dat daar samewerking tussen opvoeders en ouers moet wees om negatiewe leerdergedrag aan te spreek. Die studie dui ook aan dat kommunikasie tussen alle rolspelers van uiterse belang is om die dissiplinêre probleme binne skole aan bande te lê. Skoolleierskap moet hulle ook vergewis van die jongste metodes om dissiplinêre probleme aan te spreek. 'n Positiewe skoolklimaat of kultuur is ondersteunend om skooldissipline te verbeter.
- Full Text:
- Date Issued: 2007
- Authors: September, Willie Jeffrie
- Date: 2007
- Subjects: Classroom management -- South Africa , School discipline -- South Africa , School management teams
- Language: Afrikaans
- Type: Thesis , Masters , MEd
- Identifier: vital:9542 , http://hdl.handle.net/10948/679 , Classroom management -- South Africa , School discipline -- South Africa , School management teams
- Description: Die doel van hierdie studie is om die dissiplinêre probleme in skole soos dit in die Oudtshoorn-omgewing voorkom, te identifiseer en aan te spreek. Dit word gedoen deur te let op: • die skoolklimaat wat by 'n skool heers en die uitwerking van die skoolklimaat op die dissipline van`n skool. • die dissiplinêre probleme wat met skooldissipline in skole ervaar word. • die oorsake van skooldissipline en in watter mate die omgewing waarin die skool geleë is 'n invloed op skooldissipline het en • om oplossings vir dissiplinêre probleme soos vasgestel aan die hand te doen. Die studie poog om deur kwalitatiewe navorsingsmetodes vas te stel hoe prinsipale, opvoeders en leerders die huidige dissiplinêre situasie in skole ervaar. Dit poog dus om eerstehandse kennis te verkry van hul denke, gevoelens en gedagtes en hoe hierdie fenomeen hulle beïnvloed. Die studie kyk ook in watter mate skoolklimaat op die breë spektrum van skooldissipline 'n invloed het, en hoe die verbetering van skooldissipline `n sleutelbestuurstaak in 'n skool is. Die belangrikste bevindinge van die studie is dat daar samewerking tussen opvoeders en ouers moet wees om negatiewe leerdergedrag aan te spreek. Die studie dui ook aan dat kommunikasie tussen alle rolspelers van uiterse belang is om die dissiplinêre probleme binne skole aan bande te lê. Skoolleierskap moet hulle ook vergewis van die jongste metodes om dissiplinêre probleme aan te spreek. 'n Positiewe skoolklimaat of kultuur is ondersteunend om skooldissipline te verbeter.
- Full Text:
- Date Issued: 2007