The determination of the photosensitizing properties of mercapto substituted phthalocyanine derivatives in the presence of quantum dots capped with mercaptopropionic acid
- Moeno, Sharon, Antunes, Edith M, Nyokong, Tebello
- Authors: Moeno, Sharon , Antunes, Edith M , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247870 , vital:51625 , xlink:href="https://doi.org/10.1016/j.jphotochem.2010.12.009"
- Description: This work reports on the synthesis of several novel water soluble metallophthalocyanines containing Zn2+, In3+, Ga3+ or Si4+ as central metal ions and tetra substituted with mercaptoacetic acid and mercaptopropionic acid. The complexes were characterized using infra red, nuclear magnetic resonance and mass spectroscopies as well as elemental analysis. All the complexes are water soluble but the majority are highly aggregated in water and organic solvents. The complex containing Zn as a central metal and mercaptopropionic acid as a substituent was not aggregated allowing for the determination of photophysical parameters. This complex had triplet state quantum yield of 0.61 in DMF and 0.88 in DMSO while the fluorescence quantum yield was 0.13 in DMSO. The determination of photophysical properties of the complex containing Zn as a central metal and mercaptopropionic acid were carried out in the presence of mercaptopropionic acid capped CdTe quantum dots. There is an increase in triplet state quantum yield from 0.88 (for the phthalocyanine alone) to 0.94 (in the presence of CdTe quantum dots) in DMSO.
- Full Text:
- Date Issued: 2011
- Authors: Moeno, Sharon , Antunes, Edith M , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247870 , vital:51625 , xlink:href="https://doi.org/10.1016/j.jphotochem.2010.12.009"
- Description: This work reports on the synthesis of several novel water soluble metallophthalocyanines containing Zn2+, In3+, Ga3+ or Si4+ as central metal ions and tetra substituted with mercaptoacetic acid and mercaptopropionic acid. The complexes were characterized using infra red, nuclear magnetic resonance and mass spectroscopies as well as elemental analysis. All the complexes are water soluble but the majority are highly aggregated in water and organic solvents. The complex containing Zn as a central metal and mercaptopropionic acid as a substituent was not aggregated allowing for the determination of photophysical parameters. This complex had triplet state quantum yield of 0.61 in DMF and 0.88 in DMSO while the fluorescence quantum yield was 0.13 in DMSO. The determination of photophysical properties of the complex containing Zn as a central metal and mercaptopropionic acid were carried out in the presence of mercaptopropionic acid capped CdTe quantum dots. There is an increase in triplet state quantum yield from 0.88 (for the phthalocyanine alone) to 0.94 (in the presence of CdTe quantum dots) in DMSO.
- Full Text:
- Date Issued: 2011
The development and assessment of a fixed dose combination tablet of Ranitidine and Metronidazole
- Authors: King'ori, Loti David
- Date: 2011 , 2011-04-07
- Subjects: Ulcers -- Treatment , Ranitidine -- Evaluation , Metronidazole -- Evaluation
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3858 , http://hdl.handle.net/10962/d1013359
- Description: The oral route of drug administration is convenient since it is acceptable to most patients and the manufacturing processes used to produce tablets and capsules are relatively simple when compared to those used to manufacture other types of dosage forms. Metronidazole (MTZ) and Ranitidine (RTD) have been used in combination, as part of triple therapy for the treatment of ulcers. However the use of large numbers of tablets and long duration of therapy makes adherence to drug treatment challenging for patients. Therefore the formulation of a fixed dose combination (FDC) of MTZ and RTD may improve patient adherence to therapy and consequently may reduce morbidity and mortality due to ulcers. A stability indicating HPLC method for the simultaneous analysis of MTZ and RTD was developed and validated according to the International Conference on Harmonization (ICH) guidelines. The method was sensitive, selective, precise, accurate and linear.Preformulation studies were performed on the active pharmaceutical ingredients (API) alone and in combination with potential excipients. Differential scanning calorimetry (DSC) studies revealed a potential interaction between MTZ and RTD, however the interaction was not apparent following IR analysis of the same samples. DSC analyses of the API in combination with potential excipients revealed that the compounds were compatible with most materials with the exception of a binary mixture of RTD and Dibasic calcium phosphate (DCP) that exhibited a potential interaction. Thermal gravimetric analysis (TGA) of MTZ and RTD revealed that both compounds exhibited thermal stability. The Carrs Index (CI) and Hausner Ratio (HR) values of MTZ and RTD indicated that both compounds exhibited poor flow and compressibility properties, whereas the CI and HR values for (Microcrystalline cellulose) MCC and DCP indicated better flowability and compressibility characteristics.Direct compression and wet granulation processes were assessed to identify a suitable method of manufacture of FDC tablets of MTZ and RTD. The blends were evaluated using bulk and tapped density and the resultant tablets were evaluated for weight uniformity, crushing strength, tensile strength and disintegration time. The wet granulation method of manufacture produced tablets that showed acceptable pharmacotechnical properties: this approach was therefore used as the method of manufacture of FDC tablets of MTZ and RTD. Tablet formulations comprised of API, viz. MTZ and RTD and different compositions of MCC, DCP, Sodium starch glycolate (SSG) and Croscarmellose sodium (CCS), were manufactured in order to screen for an appropriate diluent and disintegrant composition for use in response surface studies. Assays of tablet content and in vitro drug release were undertaken using the validated HPLC method. Tablets in which MCC and CCS were used appeared to produce better assay and dissolution results as compared to those manufactured using DCP and SSG. Consequently a formulation comprised of MCC and CCS was selected and used in studies in which the effect(s) of level two formulation and composition changes as described in the Scale and Post Approval Changes for Immediate Release (SUPAC-IR) Guidelines on tablet disintegration and in vitro release were assessed. A Box-Behnken statistical design was used for the investigation of the effect of input factors, viz. CCS, (Polyvinyl pyrollidone K30) PVP-K30 and magnesium stearate on measured responses, viz. disintegration time and percent drug release in 10 minutes (Q10). CCS appeared to have an inverse linear relationship on disintegration time and a linear relationship with the Q10 for MTZ and RTD, whereas PVP-K30 and magnesium stearate appeared to have an antagonistic effect on the measured responses. Furthermore CCS and magnesium stearate exhibited an interaction that had an agonistic effect on the Q10 value for RTD. A numerical optimization approach was used to predict a formulation composition that would produce tablets that exhibited a disintegration time and Q10 values for MTZ and RTD that fell within the constraints set in our laboratory. The resultant model was found to be accurate and had a percent prediction error of < 5% for all measured response variables.FDC tablets of MTZ and RTD have been successfully produced. The disintegration of the tablet and dissolution of the API were within compendial specifications and the tablets are of suitable quality and have the potential to be further investigated to reduce the pill burden in the treatment of ulcers.
- Full Text:
- Date Issued: 2011
- Authors: King'ori, Loti David
- Date: 2011 , 2011-04-07
- Subjects: Ulcers -- Treatment , Ranitidine -- Evaluation , Metronidazole -- Evaluation
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3858 , http://hdl.handle.net/10962/d1013359
- Description: The oral route of drug administration is convenient since it is acceptable to most patients and the manufacturing processes used to produce tablets and capsules are relatively simple when compared to those used to manufacture other types of dosage forms. Metronidazole (MTZ) and Ranitidine (RTD) have been used in combination, as part of triple therapy for the treatment of ulcers. However the use of large numbers of tablets and long duration of therapy makes adherence to drug treatment challenging for patients. Therefore the formulation of a fixed dose combination (FDC) of MTZ and RTD may improve patient adherence to therapy and consequently may reduce morbidity and mortality due to ulcers. A stability indicating HPLC method for the simultaneous analysis of MTZ and RTD was developed and validated according to the International Conference on Harmonization (ICH) guidelines. The method was sensitive, selective, precise, accurate and linear.Preformulation studies were performed on the active pharmaceutical ingredients (API) alone and in combination with potential excipients. Differential scanning calorimetry (DSC) studies revealed a potential interaction between MTZ and RTD, however the interaction was not apparent following IR analysis of the same samples. DSC analyses of the API in combination with potential excipients revealed that the compounds were compatible with most materials with the exception of a binary mixture of RTD and Dibasic calcium phosphate (DCP) that exhibited a potential interaction. Thermal gravimetric analysis (TGA) of MTZ and RTD revealed that both compounds exhibited thermal stability. The Carrs Index (CI) and Hausner Ratio (HR) values of MTZ and RTD indicated that both compounds exhibited poor flow and compressibility properties, whereas the CI and HR values for (Microcrystalline cellulose) MCC and DCP indicated better flowability and compressibility characteristics.Direct compression and wet granulation processes were assessed to identify a suitable method of manufacture of FDC tablets of MTZ and RTD. The blends were evaluated using bulk and tapped density and the resultant tablets were evaluated for weight uniformity, crushing strength, tensile strength and disintegration time. The wet granulation method of manufacture produced tablets that showed acceptable pharmacotechnical properties: this approach was therefore used as the method of manufacture of FDC tablets of MTZ and RTD. Tablet formulations comprised of API, viz. MTZ and RTD and different compositions of MCC, DCP, Sodium starch glycolate (SSG) and Croscarmellose sodium (CCS), were manufactured in order to screen for an appropriate diluent and disintegrant composition for use in response surface studies. Assays of tablet content and in vitro drug release were undertaken using the validated HPLC method. Tablets in which MCC and CCS were used appeared to produce better assay and dissolution results as compared to those manufactured using DCP and SSG. Consequently a formulation comprised of MCC and CCS was selected and used in studies in which the effect(s) of level two formulation and composition changes as described in the Scale and Post Approval Changes for Immediate Release (SUPAC-IR) Guidelines on tablet disintegration and in vitro release were assessed. A Box-Behnken statistical design was used for the investigation of the effect of input factors, viz. CCS, (Polyvinyl pyrollidone K30) PVP-K30 and magnesium stearate on measured responses, viz. disintegration time and percent drug release in 10 minutes (Q10). CCS appeared to have an inverse linear relationship on disintegration time and a linear relationship with the Q10 for MTZ and RTD, whereas PVP-K30 and magnesium stearate appeared to have an antagonistic effect on the measured responses. Furthermore CCS and magnesium stearate exhibited an interaction that had an agonistic effect on the Q10 value for RTD. A numerical optimization approach was used to predict a formulation composition that would produce tablets that exhibited a disintegration time and Q10 values for MTZ and RTD that fell within the constraints set in our laboratory. The resultant model was found to be accurate and had a percent prediction error of < 5% for all measured response variables.FDC tablets of MTZ and RTD have been successfully produced. The disintegration of the tablet and dissolution of the API were within compendial specifications and the tablets are of suitable quality and have the potential to be further investigated to reduce the pill burden in the treatment of ulcers.
- Full Text:
- Date Issued: 2011
The development and implementation of a mental toughness training programme for young cricketers
- Authors: Pattison, Stuart
- Date: 2011
- Subjects: Cricket -- Psychological aspects -- South Africa -- Grahamstown , Cricket -- Training -- South Africa -- Grahamstown , Cricket players -- Mental health -- South Africa -- Grahamstown , Mental discipline , Toughness (Personality trait) , Success -- Psychological aspects , Personal coaching -- South Africa -- Grahamstown , School sports -- South Africa -- Grahamstown
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3037 , http://hdl.handle.net/10962/d1002546 , Cricket -- Psychological aspects -- South Africa -- Grahamstown , Cricket -- Training -- South Africa -- Grahamstown , Cricket players -- Mental health -- South Africa -- Grahamstown , Mental discipline , Toughness (Personality trait) , Success -- Psychological aspects , Personal coaching -- South Africa -- Grahamstown , School sports -- South Africa -- Grahamstown
- Description: Modern research being conducted on Mental Toughness is now shifting away from efforts aimed at developing definitions for the construct and instead moving toward efforts at understanding its development. This particular research study focuses on the development and implementation of a Mental Toughness programme designed specifically for, and tailored exclusively to, the needs of schoolboy cricket at Kingswood College in Grahamstown, Eastern Cape. The programme development was an intricate process and the research procedure was guided by the Organisational Development Process model. Data from a focus group as well as various individual interviews were integrated with currently existing Mental Toughness literature and theory to devise this particular Mental Toughness programme. The programme entails educating the athletes on six specific mental skills and incorporates elements of practical application as well as awareness of the importance and influence of Mental Toughness and mental training in a sporting sphere. The programme took the form of mental skills workshops held over a three week period. An analysis was conducted post-programme to document the experience of the athletes as a result of exposure to the programme. Results drawn from the array of analysis procedures were used to help identify the level of success of the Mental Toughness intervention as well as help validify current Mental Toughness models. In addition to highlighting the benefits as a result of the programme experience, various recommendations were drawn in order to shed light on the programme limitations and assist future researchers with understanding the intricacies behind better and more efficient programme implementation.
- Full Text:
- Date Issued: 2011
- Authors: Pattison, Stuart
- Date: 2011
- Subjects: Cricket -- Psychological aspects -- South Africa -- Grahamstown , Cricket -- Training -- South Africa -- Grahamstown , Cricket players -- Mental health -- South Africa -- Grahamstown , Mental discipline , Toughness (Personality trait) , Success -- Psychological aspects , Personal coaching -- South Africa -- Grahamstown , School sports -- South Africa -- Grahamstown
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3037 , http://hdl.handle.net/10962/d1002546 , Cricket -- Psychological aspects -- South Africa -- Grahamstown , Cricket -- Training -- South Africa -- Grahamstown , Cricket players -- Mental health -- South Africa -- Grahamstown , Mental discipline , Toughness (Personality trait) , Success -- Psychological aspects , Personal coaching -- South Africa -- Grahamstown , School sports -- South Africa -- Grahamstown
- Description: Modern research being conducted on Mental Toughness is now shifting away from efforts aimed at developing definitions for the construct and instead moving toward efforts at understanding its development. This particular research study focuses on the development and implementation of a Mental Toughness programme designed specifically for, and tailored exclusively to, the needs of schoolboy cricket at Kingswood College in Grahamstown, Eastern Cape. The programme development was an intricate process and the research procedure was guided by the Organisational Development Process model. Data from a focus group as well as various individual interviews were integrated with currently existing Mental Toughness literature and theory to devise this particular Mental Toughness programme. The programme entails educating the athletes on six specific mental skills and incorporates elements of practical application as well as awareness of the importance and influence of Mental Toughness and mental training in a sporting sphere. The programme took the form of mental skills workshops held over a three week period. An analysis was conducted post-programme to document the experience of the athletes as a result of exposure to the programme. Results drawn from the array of analysis procedures were used to help identify the level of success of the Mental Toughness intervention as well as help validify current Mental Toughness models. In addition to highlighting the benefits as a result of the programme experience, various recommendations were drawn in order to shed light on the programme limitations and assist future researchers with understanding the intricacies behind better and more efficient programme implementation.
- Full Text:
- Date Issued: 2011
The development and technologizing of selected Sepedi ICT terminology
- Authors: Magagane, Raesetja Linah
- Date: 2011
- Subjects: Northern Sotho language -- Terms and phrases Northern Sotho language -- Terminology Northern Sotho language -- Computer-assisted instruction Communication -- Technological innovations
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3581 , http://hdl.handle.net/10962/d1002156
- Description: It is my wish that the Sepedi language speakers, through the development and technologization of certain Sepedi ICT terminology, are able to operate a computer in their own language, and implement the new developed and technologized ICT terminology (technologization). The pupils and students at their various institutions should be made comfortable in using the developed and technologized Sepedi language terminology. In the long run the Sepedi language speakers should be ensured access to the web in order to find information about Sepedi language, culture and terms in disciplines such as ICT. It is recommended in this thesis that higher learning institutions offer bursaries to students to develop all South African languages in such a manner that they can be used in all high status functions.
- Full Text:
- Date Issued: 2011
- Authors: Magagane, Raesetja Linah
- Date: 2011
- Subjects: Northern Sotho language -- Terms and phrases Northern Sotho language -- Terminology Northern Sotho language -- Computer-assisted instruction Communication -- Technological innovations
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3581 , http://hdl.handle.net/10962/d1002156
- Description: It is my wish that the Sepedi language speakers, through the development and technologization of certain Sepedi ICT terminology, are able to operate a computer in their own language, and implement the new developed and technologized ICT terminology (technologization). The pupils and students at their various institutions should be made comfortable in using the developed and technologized Sepedi language terminology. In the long run the Sepedi language speakers should be ensured access to the web in order to find information about Sepedi language, culture and terms in disciplines such as ICT. It is recommended in this thesis that higher learning institutions offer bursaries to students to develop all South African languages in such a manner that they can be used in all high status functions.
- Full Text:
- Date Issued: 2011
The development of an in vitro system for the production of drug metabolites using microsomal enzymes from bovine liver
- Authors: Morrison, Roxanne
- Date: 2011
- Subjects: Drugs -- Metabolism , Xenobiotics -- Metabolism , Metabolites , Drugs -- Testing , Toxicity testing -- In vitro , Doping in horse racing -- Control -- Research
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4087 , http://hdl.handle.net/10962/d1007698 , Drugs -- Metabolism , Xenobiotics -- Metabolism , Metabolites , Drugs -- Testing , Toxicity testing -- In vitro , Doping in horse racing -- Control -- Research
- Description: Drug metabolism is a specialised subset of xenobiotic metabolism, pertaining to the breakdown and elimination of pharmaceutical drugs. The enzymes involved in these pathways are the cytochrome P450 family of isozymes. Metabolism is an important factor in determining the pharmacological effects of drugs. The main aim of this study was to develop a system whereby the major metabolites of drugs can be produced in vitro. An in vitro system was developed and optimised using commercially prepared microsomes from rat liver and coumarin (by monitoring its conversion to 7-hydroxycoumarin) as a model. The optimum running conditions for the incubations were 50 μM coumarin, 50 μg protein/ml microsomes, 1 mM NADP⁺, 5 mM G6P and 1U/ml G6PDH incubated for 30 minutes at 38℃. The HPLC method for the detection of coumarin and 7-hydroxycoumarin was also validated with respect to linearity, reproducibility, precision, accuracy and lower limits of detection and quantification. The system developed was then tested using microsomes prepared from fresh bovine liver on these ten drugs of interest in doping control in horse racing: diazepam, nordiazepam, oxazepam, promazine, acepromazine, chlorpromazine, morphine, codeine, etoricoxib and lumiracoxib. The bovine liver microsomes were prepared using differential centrifugation and had activity on a par with the commercial preparations. This in vitro system metabolised the drugs and produced both phase I and II metabolites, similar to those observed in humans and horses in vivo. For example, the major metabolites of the benzodiazepine drug, diazepam, nordiazepam, temazepam and oxazepam as well as the glucuronidated phase II products were all found after incubations with the bovine liver microsomes. The metabolism of the drugs was also investigated in silico using the computational procedure, MetaSite. MetaSite was able to successfully predict known metabolites for most of the drugs studied. Differences were observed from the in vitro incubations and this is most likely due to MetaSite using only human cytochrome P450s for analysis.
- Full Text:
- Date Issued: 2011
- Authors: Morrison, Roxanne
- Date: 2011
- Subjects: Drugs -- Metabolism , Xenobiotics -- Metabolism , Metabolites , Drugs -- Testing , Toxicity testing -- In vitro , Doping in horse racing -- Control -- Research
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4087 , http://hdl.handle.net/10962/d1007698 , Drugs -- Metabolism , Xenobiotics -- Metabolism , Metabolites , Drugs -- Testing , Toxicity testing -- In vitro , Doping in horse racing -- Control -- Research
- Description: Drug metabolism is a specialised subset of xenobiotic metabolism, pertaining to the breakdown and elimination of pharmaceutical drugs. The enzymes involved in these pathways are the cytochrome P450 family of isozymes. Metabolism is an important factor in determining the pharmacological effects of drugs. The main aim of this study was to develop a system whereby the major metabolites of drugs can be produced in vitro. An in vitro system was developed and optimised using commercially prepared microsomes from rat liver and coumarin (by monitoring its conversion to 7-hydroxycoumarin) as a model. The optimum running conditions for the incubations were 50 μM coumarin, 50 μg protein/ml microsomes, 1 mM NADP⁺, 5 mM G6P and 1U/ml G6PDH incubated for 30 minutes at 38℃. The HPLC method for the detection of coumarin and 7-hydroxycoumarin was also validated with respect to linearity, reproducibility, precision, accuracy and lower limits of detection and quantification. The system developed was then tested using microsomes prepared from fresh bovine liver on these ten drugs of interest in doping control in horse racing: diazepam, nordiazepam, oxazepam, promazine, acepromazine, chlorpromazine, morphine, codeine, etoricoxib and lumiracoxib. The bovine liver microsomes were prepared using differential centrifugation and had activity on a par with the commercial preparations. This in vitro system metabolised the drugs and produced both phase I and II metabolites, similar to those observed in humans and horses in vivo. For example, the major metabolites of the benzodiazepine drug, diazepam, nordiazepam, temazepam and oxazepam as well as the glucuronidated phase II products were all found after incubations with the bovine liver microsomes. The metabolism of the drugs was also investigated in silico using the computational procedure, MetaSite. MetaSite was able to successfully predict known metabolites for most of the drugs studied. Differences were observed from the in vitro incubations and this is most likely due to MetaSite using only human cytochrome P450s for analysis.
- Full Text:
- Date Issued: 2011
The development of isiZulu as an academic language for the teaching of fundamental concepts in economics
- Authors: Makhatini, Freedom Nkanyiso
- Date: 2011
- Subjects: Zulu language -- Study and teaching (Higher) -- South Africa African languages -- Study and teaching (Higher) -- South Africa Economics -- Study and teaching (Higher) -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3589 , http://hdl.handle.net/10962/d1002164
- Description: This thesis looks at language as the medium of all our ideas and sentiments. The thesis represents a position statement regarding the development of isiZulu as an academic language. The field of Economics is used to merely illustrate and support the points that are being made in this work. It is argued that each language is viewed as the means of expression of the cultural heritage of its people, and it remains a reflection of cultural groups who speak that particular language. It is a fact that indigenous African Languages have been, for obvious reasons, blatantly understudied during the apartheid years in South Africa (Rudwick 2004). Languages have market value and the desirability of English as the most important global language today has an effect in most Black learners in South Africa. The study examined the development of indigenous African languages, isiZulu in particular, in Zululand University where ninety percent of students and lecturers are isiZulu first language speakers, and came to a conclusion that there is an urgent need for Black South African students to learn academic subjects through their mother tongues. This would help them in thorough understanding and interpretation of analytic text presented in a foreign language such as English. The study advocates that isiZulu, which is the mother-tongue of many students at the University of Zululand, should be a language for upward mobility to these students, but as the situation stands, isiZulu becomes a neglected or marginalised language since it is not the normal medium of instruction and it is not used for effective communication in their education system.
- Full Text:
- Date Issued: 2011
- Authors: Makhatini, Freedom Nkanyiso
- Date: 2011
- Subjects: Zulu language -- Study and teaching (Higher) -- South Africa African languages -- Study and teaching (Higher) -- South Africa Economics -- Study and teaching (Higher) -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3589 , http://hdl.handle.net/10962/d1002164
- Description: This thesis looks at language as the medium of all our ideas and sentiments. The thesis represents a position statement regarding the development of isiZulu as an academic language. The field of Economics is used to merely illustrate and support the points that are being made in this work. It is argued that each language is viewed as the means of expression of the cultural heritage of its people, and it remains a reflection of cultural groups who speak that particular language. It is a fact that indigenous African Languages have been, for obvious reasons, blatantly understudied during the apartheid years in South Africa (Rudwick 2004). Languages have market value and the desirability of English as the most important global language today has an effect in most Black learners in South Africa. The study examined the development of indigenous African languages, isiZulu in particular, in Zululand University where ninety percent of students and lecturers are isiZulu first language speakers, and came to a conclusion that there is an urgent need for Black South African students to learn academic subjects through their mother tongues. This would help them in thorough understanding and interpretation of analytic text presented in a foreign language such as English. The study advocates that isiZulu, which is the mother-tongue of many students at the University of Zululand, should be a language for upward mobility to these students, but as the situation stands, isiZulu becomes a neglected or marginalised language since it is not the normal medium of instruction and it is not used for effective communication in their education system.
- Full Text:
- Date Issued: 2011
The development of novel cancer targeting agents
- Authors: Knoetze, Steyn
- Date: 2011
- Subjects: Cancer -- Research , Cancer -- Treatment
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:10397 , http://hdl.handle.net/10948/d1010636 , Cancer -- Research , Cancer -- Treatment
- Description: The search for the cure for cancer is currently a multi-billion dollar industry and the search for the elusive “magic bullet”, i.e. the perfect cancer drug that would interact therapeutically with cancerous tissues while having a minimal effect on healthy cells, is the topic of many research studies in the world today. A large number of novel drugs or drug complexes and conjugates are being synthesized and subjected to rigorous evaluation in the race to find the perfect cure. ECDG (Ethylene diCysteine DeoxyGlucose) seems to have promising cancer targeting ability. Even though this compound has been described in a few publications, we could not find any reference to the current use of ECDG in oncology clinics, either as a therapeutic agent, or as a diagnostic tool for imaging purposes. It was also not possible to purchase pure ECDG anywhere in the world. This prompted us to further investigate ECDG as a possible candidate for cancer targeting research, either as an imaging agent for cancer diagnosis or complexed with an anti-cancer agent for therapeutic purposes. Detailed investigations done in our laboratory can be divided into the following categories: - Development of a synthetic method for ECDG on a multigram scale ; - Purification of prepared ECDG not using the described dialysis method that only allows the purification of small quantities of ECDG (mg scale) ; Detailed investigation of the chemistry involved in the preparation of pure ECDG and its metal complexes ; - Investigation of the stability of ECDG and its metal complexes that is essential data required for any pharmaceutical agent ; - Preparation of ECDG complexes for use as a diagnostic tool, i.e. complexation with 99mTc ; Investigation of the bio distribution of ECDG-ReO complexes ; - Preparation of an ECDG kit as a diagnostic tool for use in oncology clinics. The development of novel aromatic ligands having similar characteristics compared to ECDG, containing an N2S2 chromophore as donor atoms, to further investigate their targeting capabilities, have also been investigated. All intermediates and final compounds were characterized mainly by ESI MS, in some cases IR and NMR whenever available. Successful preparation and purification of ECDG ands its metal complexes was achieved and extensively characterized and evaluated. Efforts directed towards the development of ECDG at NECSA, South Africa, were also rewarded with significant success. Furthermore, significant development regarding the synthesis of two novel compounds with ECDG-like characteristics was also completed.
- Full Text:
- Date Issued: 2011
- Authors: Knoetze, Steyn
- Date: 2011
- Subjects: Cancer -- Research , Cancer -- Treatment
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:10397 , http://hdl.handle.net/10948/d1010636 , Cancer -- Research , Cancer -- Treatment
- Description: The search for the cure for cancer is currently a multi-billion dollar industry and the search for the elusive “magic bullet”, i.e. the perfect cancer drug that would interact therapeutically with cancerous tissues while having a minimal effect on healthy cells, is the topic of many research studies in the world today. A large number of novel drugs or drug complexes and conjugates are being synthesized and subjected to rigorous evaluation in the race to find the perfect cure. ECDG (Ethylene diCysteine DeoxyGlucose) seems to have promising cancer targeting ability. Even though this compound has been described in a few publications, we could not find any reference to the current use of ECDG in oncology clinics, either as a therapeutic agent, or as a diagnostic tool for imaging purposes. It was also not possible to purchase pure ECDG anywhere in the world. This prompted us to further investigate ECDG as a possible candidate for cancer targeting research, either as an imaging agent for cancer diagnosis or complexed with an anti-cancer agent for therapeutic purposes. Detailed investigations done in our laboratory can be divided into the following categories: - Development of a synthetic method for ECDG on a multigram scale ; - Purification of prepared ECDG not using the described dialysis method that only allows the purification of small quantities of ECDG (mg scale) ; Detailed investigation of the chemistry involved in the preparation of pure ECDG and its metal complexes ; - Investigation of the stability of ECDG and its metal complexes that is essential data required for any pharmaceutical agent ; - Preparation of ECDG complexes for use as a diagnostic tool, i.e. complexation with 99mTc ; Investigation of the bio distribution of ECDG-ReO complexes ; - Preparation of an ECDG kit as a diagnostic tool for use in oncology clinics. The development of novel aromatic ligands having similar characteristics compared to ECDG, containing an N2S2 chromophore as donor atoms, to further investigate their targeting capabilities, have also been investigated. All intermediates and final compounds were characterized mainly by ESI MS, in some cases IR and NMR whenever available. Successful preparation and purification of ECDG ands its metal complexes was achieved and extensively characterized and evaluated. Efforts directed towards the development of ECDG at NECSA, South Africa, were also rewarded with significant success. Furthermore, significant development regarding the synthesis of two novel compounds with ECDG-like characteristics was also completed.
- Full Text:
- Date Issued: 2011
The dialogue between the bench and the bar: implications for adjudicative impartiality
- Okpaluba, Chuks, Juma, Laurence
- Authors: Okpaluba, Chuks , Juma, Laurence
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/129078 , vital:36215 , https://hdl.handle.net/10520/EJC53998
- Description: What is the role of the judge in the conduct of a trial? Can he or she engage counsel in legal argument and ask questions on legal issues without breaking the brittle bond of justice or be said to have 'descended into the arena'? Assuming that these actions are permissible, at what point will the judge's dialogue with counsel or line of questioning go beyond permissible limits? These are the questions with which this article grapples. Based on an analysis of the Constitutional Court decisions in State v Basson (2) 2007 (1) SACR 566 (CC) and Bernert v ABSA Bank Ltd 2011 (3) SA 92 (CC), and several Supreme Court of Appeal and other Commonwealth decisions, the article explores the circumstances in which the recusal of judges has been sought, or judicial decisions have been challenged on appeal on the basis of an allegation that there have been violations of the principle of fair hearing as enshrined in the Constitution. The article draws on the 'apprehension of bias' jurisprudence to establish the utility of the presumption of impartiality and the hybrid test of double-reasonableness in contexts where a judge's conduct is in question. The article concludes that the dialogue between the bench and bar is a useful component of adjudication in our adversarial system and should be limited by the rules of impartiality only in very exceptional circumstances.
- Full Text: false
- Date Issued: 2011
- Authors: Okpaluba, Chuks , Juma, Laurence
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/129078 , vital:36215 , https://hdl.handle.net/10520/EJC53998
- Description: What is the role of the judge in the conduct of a trial? Can he or she engage counsel in legal argument and ask questions on legal issues without breaking the brittle bond of justice or be said to have 'descended into the arena'? Assuming that these actions are permissible, at what point will the judge's dialogue with counsel or line of questioning go beyond permissible limits? These are the questions with which this article grapples. Based on an analysis of the Constitutional Court decisions in State v Basson (2) 2007 (1) SACR 566 (CC) and Bernert v ABSA Bank Ltd 2011 (3) SA 92 (CC), and several Supreme Court of Appeal and other Commonwealth decisions, the article explores the circumstances in which the recusal of judges has been sought, or judicial decisions have been challenged on appeal on the basis of an allegation that there have been violations of the principle of fair hearing as enshrined in the Constitution. The article draws on the 'apprehension of bias' jurisprudence to establish the utility of the presumption of impartiality and the hybrid test of double-reasonableness in contexts where a judge's conduct is in question. The article concludes that the dialogue between the bench and bar is a useful component of adjudication in our adversarial system and should be limited by the rules of impartiality only in very exceptional circumstances.
- Full Text: false
- Date Issued: 2011
The discoursal construction of female physical identity in selected works in children's literature
- Authors: Hunt, Sally Ann
- Date: 2011 , 2013-09-20
- Subjects: Rowling, J K -- Criticism and interpretation Lewis, C S (Clive Staples), 1898-1963 -- Criticism and interpretation Girls in literature Girls -- Identity Human body in literature Gender identity in literature Sex role in literature Children's stories, English -- History and criticism Young women in literature Women in literature
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2377 , http://hdl.handle.net/10962/d1005965
- Description: This thesis reports on an analysis of the discursive construction of female and male physical identity in children’s literature and explicitly combines corpus linguistic methods with a critical discourse approach. Based on three novels from each of the Chronicles of Narnia and the Harry Potter series, it shows clear gendering of body parts, not only in terms of the purely quantitative preferences for certain body parts to be associated with one or other gender, but in terms of discourse prosody, or the uses to which the body parts are put. Human body parts in these series are mostly used in the following four ways, all of which show differences in realisation in terms of gender: · to describe individuals, physically, in order to distinguish one from the other; · to convey emotion, unintentionally as well as consciously; · for physical interaction between people and · for interaction with the world more broadly: responses to danger and agency, i.e. the ability to act on the world and the nature of what is achieved. The use of body parts by characters to express emotion and act agentively on the world is revealed to be strongly gendered in the two series. I characterise the most prominent patterns in terms of the bodily products blood, sweat and tears, of which the last is strongly connected to female characters, who are generally associated with emotion. The other two, referring to active participation in fighting and injury, as well as agency, are almost exclusively reserved for males, with female characters rendered unable to act on the physical world as a result of overwhelming feelings. The females’ response to danger suggests stereotyped discourses of inequality which see women and girls as requiring protection and being physically incapable. Thus gender is still a particularly salient aspect in these widely-read examples of children’s literature, despite plots which appear to be fairly positive towards women. The strength of the inclusion of a corpus approach in this study lies in its capacity to reveal objective, and often fairly covert, trends in language use. These in turn enrich the critical analysis of discourses in these influential texts, which facilitates social change through linguistic analysis.
- Full Text:
- Date Issued: 2011
- Authors: Hunt, Sally Ann
- Date: 2011 , 2013-09-20
- Subjects: Rowling, J K -- Criticism and interpretation Lewis, C S (Clive Staples), 1898-1963 -- Criticism and interpretation Girls in literature Girls -- Identity Human body in literature Gender identity in literature Sex role in literature Children's stories, English -- History and criticism Young women in literature Women in literature
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2377 , http://hdl.handle.net/10962/d1005965
- Description: This thesis reports on an analysis of the discursive construction of female and male physical identity in children’s literature and explicitly combines corpus linguistic methods with a critical discourse approach. Based on three novels from each of the Chronicles of Narnia and the Harry Potter series, it shows clear gendering of body parts, not only in terms of the purely quantitative preferences for certain body parts to be associated with one or other gender, but in terms of discourse prosody, or the uses to which the body parts are put. Human body parts in these series are mostly used in the following four ways, all of which show differences in realisation in terms of gender: · to describe individuals, physically, in order to distinguish one from the other; · to convey emotion, unintentionally as well as consciously; · for physical interaction between people and · for interaction with the world more broadly: responses to danger and agency, i.e. the ability to act on the world and the nature of what is achieved. The use of body parts by characters to express emotion and act agentively on the world is revealed to be strongly gendered in the two series. I characterise the most prominent patterns in terms of the bodily products blood, sweat and tears, of which the last is strongly connected to female characters, who are generally associated with emotion. The other two, referring to active participation in fighting and injury, as well as agency, are almost exclusively reserved for males, with female characters rendered unable to act on the physical world as a result of overwhelming feelings. The females’ response to danger suggests stereotyped discourses of inequality which see women and girls as requiring protection and being physically incapable. Thus gender is still a particularly salient aspect in these widely-read examples of children’s literature, despite plots which appear to be fairly positive towards women. The strength of the inclusion of a corpus approach in this study lies in its capacity to reveal objective, and often fairly covert, trends in language use. These in turn enrich the critical analysis of discourses in these influential texts, which facilitates social change through linguistic analysis.
- Full Text:
- Date Issued: 2011
The disempowering faces of the flexible firm: a case study of Gaborone Private Hospital
- Authors: Makorie, Theona Tariro
- Date: 2011
- Subjects: Gaberone Private Hospital -- Employees , Gaberone Private Hospital -- Personnel management , Gaberone Private Hospital -- Management , Nursing services -- Administration , Nurses -- Employment -- Botswana , Nursing -- Law and legislation -- Botswana , Hospitals -- Medical staff -- Botswana , Hospitals -- Administration -- Botswana
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:3352
- Description: The purpose of the study was to investigate the ways in which the practice of t the Flexible Firm Model (FFM) disempowered the non-citizen professional nurses at Gaborone Private Hospital (GPH) in Gaborone, Botswana. GPH is a member of the Life Health care group of private hospitals based in South Africa. This study sought to probe the manner in which the practice of FFM influenced the employment relationship for non-citizen professional nurses. It also sought to examine the impact of the nature of the employment relationship on career development and representation and participation. Both qualitative and quantitative research methodologies were applied. Questionnaires were used to collect quantitative data. Thirty-five questionnaires were issued out to professional nursing staff and thirty-three responses were received. The response rate was ninety-four percent. The qualitative research data consisted of twelve in-depth interviews with professional nurses, the human resources manager , a professional nurse agency owner and a private clinic co-owner. Document analysis in the form of labour legislation, employee guides and employment contracts was used to validate data collected from the in-depth interviews. The results from the questionnaire revealed that an overwhelming majority of the professional nurses were Non-Citizens' dependent contractors. Although just under half of the participants held two or more previous contracts with GPH, an overwhelming majority had never been promoted. In addition, none of the participants were affiliated to the Botswana Nurses Association (BNA), the local equivalency of a professional nursing trade union. The in-depth interviews disclosed a sense of helplessness at their perceived disempowerment within the employment relationship, a poor career development and weak representation and participation. This study concluded that disempowerment at GPH was manifested through worker representation and participation and in effective skill upgrade. These forms of disempowerment were made worse by the global professional nurse shortage and maladministration of avail able human resources. Effective use of human resources and continued education could be employed to circumvent the adverse results of disempowerment.
- Full Text:
- Date Issued: 2011
- Authors: Makorie, Theona Tariro
- Date: 2011
- Subjects: Gaberone Private Hospital -- Employees , Gaberone Private Hospital -- Personnel management , Gaberone Private Hospital -- Management , Nursing services -- Administration , Nurses -- Employment -- Botswana , Nursing -- Law and legislation -- Botswana , Hospitals -- Medical staff -- Botswana , Hospitals -- Administration -- Botswana
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:3352
- Description: The purpose of the study was to investigate the ways in which the practice of t the Flexible Firm Model (FFM) disempowered the non-citizen professional nurses at Gaborone Private Hospital (GPH) in Gaborone, Botswana. GPH is a member of the Life Health care group of private hospitals based in South Africa. This study sought to probe the manner in which the practice of FFM influenced the employment relationship for non-citizen professional nurses. It also sought to examine the impact of the nature of the employment relationship on career development and representation and participation. Both qualitative and quantitative research methodologies were applied. Questionnaires were used to collect quantitative data. Thirty-five questionnaires were issued out to professional nursing staff and thirty-three responses were received. The response rate was ninety-four percent. The qualitative research data consisted of twelve in-depth interviews with professional nurses, the human resources manager , a professional nurse agency owner and a private clinic co-owner. Document analysis in the form of labour legislation, employee guides and employment contracts was used to validate data collected from the in-depth interviews. The results from the questionnaire revealed that an overwhelming majority of the professional nurses were Non-Citizens' dependent contractors. Although just under half of the participants held two or more previous contracts with GPH, an overwhelming majority had never been promoted. In addition, none of the participants were affiliated to the Botswana Nurses Association (BNA), the local equivalency of a professional nursing trade union. The in-depth interviews disclosed a sense of helplessness at their perceived disempowerment within the employment relationship, a poor career development and weak representation and participation. This study concluded that disempowerment at GPH was manifested through worker representation and participation and in effective skill upgrade. These forms of disempowerment were made worse by the global professional nurse shortage and maladministration of avail able human resources. Effective use of human resources and continued education could be employed to circumvent the adverse results of disempowerment.
- Full Text:
- Date Issued: 2011
The distribution, abundance and composition of street trees in selected towns of the Eastern Cape, South Africa
- Kuruneri-Chitepo, C, Shackleton, Charlie M
- Authors: Kuruneri-Chitepo, C , Shackleton, Charlie M
- Date: 2011
- Language: English
- Type: Article
- Identifier: vital:6639 , http://hdl.handle.net/10962/d1006865
- Description: Street trees are an important component of the urban forest as they provide critical ecosystem services which contribute to human health and environmental quality. However, little is known about the distribution, diversity and density of street trees, particularly in the developing world where urbanisation is most rapid. Thus, the aim of this paper was to assess the distribution, composition and abundance of street trees across three towns along an environmental gradient in the Eastern Cape of South Africa, and identify the key challenges faced by local officials concerned with the provision of street trees. In each town, streets were randomly sampled in the commercial, affluent residential, township settlement and low cost housing areas under the Reconstruction and Development Program (RDP). Attributes recorded per tree were species, circumference, height and health, while semi-structured interviews were conducted with the municipal officials involved in the establishment and maintenance of street trees. A total of 1,485 trees were encountered, comprising 61 species. The majority (56%) of trees were alien species. Noticeable differences in tree density and species richness were evident across suburbs, being highest in the more affluent suburbs and poorly represented in the low income township and RDP areas. There was a decreasing mean tree height and health score along the environmental gradient from the coastal town to the inland town. Although awareness of the benefits of street trees was high, as was the need to reduce the proportion of alien species, the primary constraint to establishment and maintenance of street trees in the three towns was limited budget and human resources.
- Full Text:
- Date Issued: 2011
- Authors: Kuruneri-Chitepo, C , Shackleton, Charlie M
- Date: 2011
- Language: English
- Type: Article
- Identifier: vital:6639 , http://hdl.handle.net/10962/d1006865
- Description: Street trees are an important component of the urban forest as they provide critical ecosystem services which contribute to human health and environmental quality. However, little is known about the distribution, diversity and density of street trees, particularly in the developing world where urbanisation is most rapid. Thus, the aim of this paper was to assess the distribution, composition and abundance of street trees across three towns along an environmental gradient in the Eastern Cape of South Africa, and identify the key challenges faced by local officials concerned with the provision of street trees. In each town, streets were randomly sampled in the commercial, affluent residential, township settlement and low cost housing areas under the Reconstruction and Development Program (RDP). Attributes recorded per tree were species, circumference, height and health, while semi-structured interviews were conducted with the municipal officials involved in the establishment and maintenance of street trees. A total of 1,485 trees were encountered, comprising 61 species. The majority (56%) of trees were alien species. Noticeable differences in tree density and species richness were evident across suburbs, being highest in the more affluent suburbs and poorly represented in the low income township and RDP areas. There was a decreasing mean tree height and health score along the environmental gradient from the coastal town to the inland town. Although awareness of the benefits of street trees was high, as was the need to reduce the proportion of alien species, the primary constraint to establishment and maintenance of street trees in the three towns was limited budget and human resources.
- Full Text:
- Date Issued: 2011
The diversity of aquatic insects in the Tsitsikamma region, with implications for aquatic ecosystem conservation
- Authors: Bellingan, Terence Andrew
- Date: 2011
- Subjects: Aquatic insects -- South Africa -- Tsitsikamma , Aquatic insects -- Classification -- South Africa -- Tsitsikamma , Aquatic ecology -- South Africa -- Tsitsikamma , Ecosystem management -- South Africa -- Tsitsikamma , Stream conservation -- South Africa -- Tsitsikamma
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5664 , http://hdl.handle.net/10962/d1005348 , Aquatic insects -- South Africa -- Tsitsikamma , Aquatic insects -- Classification -- South Africa -- Tsitsikamma , Aquatic ecology -- South Africa -- Tsitsikamma , Ecosystem management -- South Africa -- Tsitsikamma , Stream conservation -- South Africa -- Tsitsikamma
- Description: As a result of research carried out within the last decade to assess the diversity of macroinvertebrates of the Salt River in the Western Cape Province, South Africa, surveys of macroinvertebrates of 20 sites on 11 selected rivers from the same mountain range source were undertaken. This was done to make a preliminary assessment of the conservation status of the rivers of this region. Aquatic insects from the orders Ephemeroptera, Odonata, Plecoptera, Megaloptera, Trichoptera and the dipteran family Simuliidae were collected using techniques to maximize the number of taxa found. The insects collected were identified to species level where possible. Water physicochemical parameters were recorded at all sites for each sampling trip to characterize these rivers and to establish a set of baseline data for future comparisons. These parameters included measurements made on site and analysis of the concentrations of all the major ions in water samples in the laboratory. Multivariate analyses including Principle Components Analysis and Canonical Correspondence Analysis were used to reveal patterns within the water physicochemistry and species distributional data. Results include the identification of 123 species from 70 genera and 30 families. A total of 31 species were found to be undescribed, of which 17 were not previously collected and are thus completely new to science. In addition, four of these species could not be placed into any known genus. The analysis of water physicochemistry showed a clear distinction between rivers of Table Mountain sandstone and Bokkeveld shale origin. Downstream effects of anthropogenic influences were discernable too. Distinct macroinvertebrate assemblages were found based upon stream order and water chemistry composition. pH proved to be the most important driver of invertebrate assemblage composition. The high levels of endemism of the macroinvertebrates found within the upper reaches of these rivers and their degree of ecological specialization make these systems a priority for the conservation of aquatic biodiversity on a national and global scale.
- Full Text:
- Date Issued: 2011
- Authors: Bellingan, Terence Andrew
- Date: 2011
- Subjects: Aquatic insects -- South Africa -- Tsitsikamma , Aquatic insects -- Classification -- South Africa -- Tsitsikamma , Aquatic ecology -- South Africa -- Tsitsikamma , Ecosystem management -- South Africa -- Tsitsikamma , Stream conservation -- South Africa -- Tsitsikamma
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5664 , http://hdl.handle.net/10962/d1005348 , Aquatic insects -- South Africa -- Tsitsikamma , Aquatic insects -- Classification -- South Africa -- Tsitsikamma , Aquatic ecology -- South Africa -- Tsitsikamma , Ecosystem management -- South Africa -- Tsitsikamma , Stream conservation -- South Africa -- Tsitsikamma
- Description: As a result of research carried out within the last decade to assess the diversity of macroinvertebrates of the Salt River in the Western Cape Province, South Africa, surveys of macroinvertebrates of 20 sites on 11 selected rivers from the same mountain range source were undertaken. This was done to make a preliminary assessment of the conservation status of the rivers of this region. Aquatic insects from the orders Ephemeroptera, Odonata, Plecoptera, Megaloptera, Trichoptera and the dipteran family Simuliidae were collected using techniques to maximize the number of taxa found. The insects collected were identified to species level where possible. Water physicochemical parameters were recorded at all sites for each sampling trip to characterize these rivers and to establish a set of baseline data for future comparisons. These parameters included measurements made on site and analysis of the concentrations of all the major ions in water samples in the laboratory. Multivariate analyses including Principle Components Analysis and Canonical Correspondence Analysis were used to reveal patterns within the water physicochemistry and species distributional data. Results include the identification of 123 species from 70 genera and 30 families. A total of 31 species were found to be undescribed, of which 17 were not previously collected and are thus completely new to science. In addition, four of these species could not be placed into any known genus. The analysis of water physicochemistry showed a clear distinction between rivers of Table Mountain sandstone and Bokkeveld shale origin. Downstream effects of anthropogenic influences were discernable too. Distinct macroinvertebrate assemblages were found based upon stream order and water chemistry composition. pH proved to be the most important driver of invertebrate assemblage composition. The high levels of endemism of the macroinvertebrates found within the upper reaches of these rivers and their degree of ecological specialization make these systems a priority for the conservation of aquatic biodiversity on a national and global scale.
- Full Text:
- Date Issued: 2011
The druggable antimalarial target 1-deoxy-D-xylulose-5-phosphate reductoisomerase: purfication, kinetic characterization and inhibition studies
- Authors: Goble, Jessica Leigh
- Date: 2011
- Subjects: Antimalarials -- Development Plasmodium falciparum Drug development Plasmodium falciparum -- Purification Plasmodium falciparum -- Inhibitors Enzyme kinetics Malaria -- Chemotherapy
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3949 , http://hdl.handle.net/10962/d1004008
- Description: Plasmodium falciparum 1–deoxy–D–xylulose–5 phosphatereductoisomerase (PfDXR) plays a role in isoprenoid biosynthesis in the malaria parasite and is absent in the human host, making this parasite enzyme an attractive target for antimalarial drug design. To characterize PfDXR, it is necessary to produce large quantities of the enzyme in a soluble and functional form. However, the over–production of malarial proteins in prokaryotic host systems often results in the formation of truncated proteins or insoluble protein aggregates. A heterologous expression system was developed for the production of active PfDXR using codon harmonization and tight control of expression in the presence of lac repressor. Yields of up to 2 mg/l of enzyme were reported using the optimised expression system, which is 8 to 10– fold greater than previously reported yields. The kinetic parameters Km, Vmax and kcat were determined for PfDXR; values reported in this study were consistent with those reported in the literature for other DXR enzymes. A three–dimensional model of the malarial drug target protein PfDXR was generated, and validated using structure–checking programs and protein docking studies. Structural and functional features unique to PfDXR were identified using the model and comparative sequence analyses with apicomplexan and non–apicomplexan DXR proteins. Residues Val44 and Asn45, essential for NADPH binding; and catalytic hatch residues Lys224 and Lys226, which are unique to the species of Plasmodium, were mutated to resemble those of E. coli DXR. Interestingly,these mutations resulted in significant reductions in substrate affinity, when compared to the unmutated PfDXR. Mutant enzymes PfDXR(VN43,44AG) and PfDXR(KK224,226NS) also demonstrated a decreased ability to turnover substrate by 4–fold and 2–fold respectively. This study indicates a difference in the role of the catalytic hatch of PfDXR with regards to the way in which it captures substrates. The study also highlights subtle differences in cofactor binding to PfDXR, compared with the well characterized EcDXR enzyme. The validated PfDXR model was also used to develop a novel efficient in silico screening method for potential tool compounds for use in the rational design of novel DXR inhibitors. Following in silico screening of 46 potential DXR inhibitors, a two–tiered in vitro screening approach was undertaken. DXR inhibition was assessed for the 46 novel compounds using an NADPH– ependant DXP enzyme inhibition assay and antimalarial potential was assessed using P.falciparum–infected erythrocyte growth assays. Select compounds were tested in human cells in order to determine whether they were toxic to the host. From the parallel in silico and in vitro drug screening, it was evident that only a single compound demonstrated reasonable potential binding to DXR (determined using in silico docking), inhibited DXR in vitro and inhibited P. falciparum growth, without being toxic to human cells. Its potential as a lead compound in antimalarial drug development is therefore feasible. Two outcomes were evident from this work. Firstly, analogues of known antimalarial natural products can be screened against malaria, which may then lead towards the rational design of novel compounds that are effective against a specific antimalarial drug target enzyme, such as PfDXR. Secondly, the rational design of novel compounds against a specific antimalarial drug target enzyme can be untaken by adopting a coupled in silico and in vitro approach to drug discovery.
- Full Text:
- Date Issued: 2011
- Authors: Goble, Jessica Leigh
- Date: 2011
- Subjects: Antimalarials -- Development Plasmodium falciparum Drug development Plasmodium falciparum -- Purification Plasmodium falciparum -- Inhibitors Enzyme kinetics Malaria -- Chemotherapy
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3949 , http://hdl.handle.net/10962/d1004008
- Description: Plasmodium falciparum 1–deoxy–D–xylulose–5 phosphatereductoisomerase (PfDXR) plays a role in isoprenoid biosynthesis in the malaria parasite and is absent in the human host, making this parasite enzyme an attractive target for antimalarial drug design. To characterize PfDXR, it is necessary to produce large quantities of the enzyme in a soluble and functional form. However, the over–production of malarial proteins in prokaryotic host systems often results in the formation of truncated proteins or insoluble protein aggregates. A heterologous expression system was developed for the production of active PfDXR using codon harmonization and tight control of expression in the presence of lac repressor. Yields of up to 2 mg/l of enzyme were reported using the optimised expression system, which is 8 to 10– fold greater than previously reported yields. The kinetic parameters Km, Vmax and kcat were determined for PfDXR; values reported in this study were consistent with those reported in the literature for other DXR enzymes. A three–dimensional model of the malarial drug target protein PfDXR was generated, and validated using structure–checking programs and protein docking studies. Structural and functional features unique to PfDXR were identified using the model and comparative sequence analyses with apicomplexan and non–apicomplexan DXR proteins. Residues Val44 and Asn45, essential for NADPH binding; and catalytic hatch residues Lys224 and Lys226, which are unique to the species of Plasmodium, were mutated to resemble those of E. coli DXR. Interestingly,these mutations resulted in significant reductions in substrate affinity, when compared to the unmutated PfDXR. Mutant enzymes PfDXR(VN43,44AG) and PfDXR(KK224,226NS) also demonstrated a decreased ability to turnover substrate by 4–fold and 2–fold respectively. This study indicates a difference in the role of the catalytic hatch of PfDXR with regards to the way in which it captures substrates. The study also highlights subtle differences in cofactor binding to PfDXR, compared with the well characterized EcDXR enzyme. The validated PfDXR model was also used to develop a novel efficient in silico screening method for potential tool compounds for use in the rational design of novel DXR inhibitors. Following in silico screening of 46 potential DXR inhibitors, a two–tiered in vitro screening approach was undertaken. DXR inhibition was assessed for the 46 novel compounds using an NADPH– ependant DXP enzyme inhibition assay and antimalarial potential was assessed using P.falciparum–infected erythrocyte growth assays. Select compounds were tested in human cells in order to determine whether they were toxic to the host. From the parallel in silico and in vitro drug screening, it was evident that only a single compound demonstrated reasonable potential binding to DXR (determined using in silico docking), inhibited DXR in vitro and inhibited P. falciparum growth, without being toxic to human cells. Its potential as a lead compound in antimalarial drug development is therefore feasible. Two outcomes were evident from this work. Firstly, analogues of known antimalarial natural products can be screened against malaria, which may then lead towards the rational design of novel compounds that are effective against a specific antimalarial drug target enzyme, such as PfDXR. Secondly, the rational design of novel compounds against a specific antimalarial drug target enzyme can be untaken by adopting a coupled in silico and in vitro approach to drug discovery.
- Full Text:
- Date Issued: 2011
The economic impact of HIV and AIDS in South Africa
- Makhetha, Palesa (https://orcid.org/0000-0001-8730-4450)
- Authors: Makhetha, Palesa (https://orcid.org/0000-0001-8730-4450)
- Date: 2011
- Subjects: AIDS (Disease) , Economic Aspects , HIV Infections South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/26130 , vital:64918
- Description: The SADC region has felt the impact of HIV/AIDS more than any other region in sub-Saharan Africa and the world. South Africa is the home of the largest number of people living with HIV/AIDS in the world. Historically, South Africa is one the countries that had a very disorderly past and this history is relevant to the explosive spread of HIV/AIDS in the region. The first cases of HIV were diagnosed in 1982 and that is when the first death from this disease was recorded. In 2004 over 5 million people out of a total 46 million South Africans were HIV positive, giving a total prevalence rate of 11 percent. HIV/AIDS has affected societies in many ways. Individuals, households and enterprises have all been affected by the pandemic. For individuals, incomes are lost as a result of HIV/AIDS. When individuals fall sick due to the disease, they loose their jobs and incomes. In most cases, these individuals are breadwinners in their households. The available money is then spent on medical services at the expense of other household investments. For example, the loss of a breadwinner inevitably affects rural households investments on farm inputs such as fertiliser, seeds etc. The result is low agricultural output and thus poverty. Dependent members of the households suffer immensely from the loss of income. Those at school are likely to drop out. When children drop out of school, they are more likely to be unemployed or underemployed. This makes them more vulnerable to being poor and other vices, such as crime or even HIV/AIDS. Poverty is another social and health issue that has a two-way relationship with HIV/Aids. Poverty increases individuals’ vulnerability to HIV/AIDS especially for females. Through its impact on productivity and loss of life of the economically productive members of the society, the disease condemns many to poverty. Households affected by the disease, are poorer than non-affected households. , Thesis (MA) -- Faculty of Management and Commerce, 2011
- Full Text:
- Date Issued: 2011
- Authors: Makhetha, Palesa (https://orcid.org/0000-0001-8730-4450)
- Date: 2011
- Subjects: AIDS (Disease) , Economic Aspects , HIV Infections South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/26130 , vital:64918
- Description: The SADC region has felt the impact of HIV/AIDS more than any other region in sub-Saharan Africa and the world. South Africa is the home of the largest number of people living with HIV/AIDS in the world. Historically, South Africa is one the countries that had a very disorderly past and this history is relevant to the explosive spread of HIV/AIDS in the region. The first cases of HIV were diagnosed in 1982 and that is when the first death from this disease was recorded. In 2004 over 5 million people out of a total 46 million South Africans were HIV positive, giving a total prevalence rate of 11 percent. HIV/AIDS has affected societies in many ways. Individuals, households and enterprises have all been affected by the pandemic. For individuals, incomes are lost as a result of HIV/AIDS. When individuals fall sick due to the disease, they loose their jobs and incomes. In most cases, these individuals are breadwinners in their households. The available money is then spent on medical services at the expense of other household investments. For example, the loss of a breadwinner inevitably affects rural households investments on farm inputs such as fertiliser, seeds etc. The result is low agricultural output and thus poverty. Dependent members of the households suffer immensely from the loss of income. Those at school are likely to drop out. When children drop out of school, they are more likely to be unemployed or underemployed. This makes them more vulnerable to being poor and other vices, such as crime or even HIV/AIDS. Poverty is another social and health issue that has a two-way relationship with HIV/Aids. Poverty increases individuals’ vulnerability to HIV/AIDS especially for females. Through its impact on productivity and loss of life of the economically productive members of the society, the disease condemns many to poverty. Households affected by the disease, are poorer than non-affected households. , Thesis (MA) -- Faculty of Management and Commerce, 2011
- Full Text:
- Date Issued: 2011
The economics of Bt maize/yieldgard production: case of smallholder farmers in the Eastern Cape Province
- Mandikiana, Brian Washington
- Authors: Mandikiana, Brian Washington
- Date: 2011
- Subjects: Corn -- Planting , Corn -- South Africa -- Eastern Cape , Corn -- South Africa -- Economic conditions , Farms, Small -- South Africa -- Eastern Cape , Bacillus thuringiensis , Bacillus (Bacteria) , Food security -- South Africa -- Eastern Cape , Food supply -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc Agric (Agricultural Economics)
- Identifier: vital:11167 , http://hdl.handle.net/10353/326 , Corn -- Planting , Corn -- South Africa -- Eastern Cape , Corn -- South Africa -- Economic conditions , Farms, Small -- South Africa -- Eastern Cape , Bacillus thuringiensis , Bacillus (Bacteria) , Food security -- South Africa -- Eastern Cape , Food supply -- South Africa -- Eastern Cape
- Description: Maize is the staple food for most South Africans. This implies that any damage to the maize crop will affect food security of many South Africans. Although Eastern Cape Province is not a traditionally maize producing area, smallholder farmers in the province produce it mostly for subsistence purposes and some sell the surplus on the local market or use it to secure other good through barter trading. In South Africa, insect-resistant Bt maize/yieldgard has been used commercially for approximately 10 years now. Available impact studies on Bt maize reveal that, this technology is beneficial not only to farmers but consumers of maize products as well. Welfare gains as well as positive effects for human health are realised by both groups. Due to the costs and effectiveness associated with traditional and conventional maize stem borer control methods, Bt technology has the potential to be part of the solution. This thesis has attempted to investigate the economic viability of planting Bt maize seeds under smallholder farming conditions and identify factors as well as perceptions relating to attributes of Bt maize and to analyze the relationships between those perceptions and choices regarding use of Bt technology. Data was collected from 90 households who were selected using purposive sampling through the use of the snowball method. To collect data, a questionnaire was administered through face-to-face interviews. Gross margin analysis revealed that Bt maize is a more profitable option as compared to conventional maize seeds. Furthermore, econometric analyses, through use of the binomial regression model revealed that perceptions could be used to distinguish between users and non-users of Bt maize seed in the Eastern Cape Province. Results of inferential analysis indicate that the statistically significant variables at 5% level are gene erosion, quality and nutrition of products and food labels for Bt maize products perceptions. On the other hand, low expenses, seed market availability and farmers’ knowledge perceptions were significant at 10%. These findings suggest that an adjustment in each one of the significant variables can significantly influence the probability of Bt maize adoption. In view of the research findings, several policy proposals are suggested to support policy formulation. Key words: Bacillus thuringiensis (Bt) maize, yieldgard, smallholder farmers, perceptions, Flagstaff, gross margin analysis, binomial logistic regression model, Eastern Cape Province.
- Full Text:
- Date Issued: 2011
- Authors: Mandikiana, Brian Washington
- Date: 2011
- Subjects: Corn -- Planting , Corn -- South Africa -- Eastern Cape , Corn -- South Africa -- Economic conditions , Farms, Small -- South Africa -- Eastern Cape , Bacillus thuringiensis , Bacillus (Bacteria) , Food security -- South Africa -- Eastern Cape , Food supply -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc Agric (Agricultural Economics)
- Identifier: vital:11167 , http://hdl.handle.net/10353/326 , Corn -- Planting , Corn -- South Africa -- Eastern Cape , Corn -- South Africa -- Economic conditions , Farms, Small -- South Africa -- Eastern Cape , Bacillus thuringiensis , Bacillus (Bacteria) , Food security -- South Africa -- Eastern Cape , Food supply -- South Africa -- Eastern Cape
- Description: Maize is the staple food for most South Africans. This implies that any damage to the maize crop will affect food security of many South Africans. Although Eastern Cape Province is not a traditionally maize producing area, smallholder farmers in the province produce it mostly for subsistence purposes and some sell the surplus on the local market or use it to secure other good through barter trading. In South Africa, insect-resistant Bt maize/yieldgard has been used commercially for approximately 10 years now. Available impact studies on Bt maize reveal that, this technology is beneficial not only to farmers but consumers of maize products as well. Welfare gains as well as positive effects for human health are realised by both groups. Due to the costs and effectiveness associated with traditional and conventional maize stem borer control methods, Bt technology has the potential to be part of the solution. This thesis has attempted to investigate the economic viability of planting Bt maize seeds under smallholder farming conditions and identify factors as well as perceptions relating to attributes of Bt maize and to analyze the relationships between those perceptions and choices regarding use of Bt technology. Data was collected from 90 households who were selected using purposive sampling through the use of the snowball method. To collect data, a questionnaire was administered through face-to-face interviews. Gross margin analysis revealed that Bt maize is a more profitable option as compared to conventional maize seeds. Furthermore, econometric analyses, through use of the binomial regression model revealed that perceptions could be used to distinguish between users and non-users of Bt maize seed in the Eastern Cape Province. Results of inferential analysis indicate that the statistically significant variables at 5% level are gene erosion, quality and nutrition of products and food labels for Bt maize products perceptions. On the other hand, low expenses, seed market availability and farmers’ knowledge perceptions were significant at 10%. These findings suggest that an adjustment in each one of the significant variables can significantly influence the probability of Bt maize adoption. In view of the research findings, several policy proposals are suggested to support policy formulation. Key words: Bacillus thuringiensis (Bt) maize, yieldgard, smallholder farmers, perceptions, Flagstaff, gross margin analysis, binomial logistic regression model, Eastern Cape Province.
- Full Text:
- Date Issued: 2011
The education sector as an essential service
- Authors: Adams, Anton John
- Date: 2011
- Subjects: Educational law and legislation -- South Africa , Teachers -- Legal status, laws, etc. -- South Africa , Right to education -- Law and legislation -- South Africa , Basic education -- South Africa , Human rights -- Study and teaching
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:10188 , http://hdl.handle.net/10948/1573 , Educational law and legislation -- South Africa , Teachers -- Legal status, laws, etc. -- South Africa , Right to education -- Law and legislation -- South Africa , Basic education -- South Africa , Human rights -- Study and teaching
- Description: Because of the impact of teacher strikes on education there has been a call to declare the teacher‟s profession an essential service and thus prohibit them from striking. This call was made by the Democratic Alliance (DA). The Democratic Alliance arguments in their application to the Essential Services Committee was based on the fact that education in South Africa is in a crisis and the life-altering inconvenience this caused for children. The combined teacher unions in the Education Labour Relations Council (ELRC) expressed their concerns over the DA‟s call for education to be declared an Essential Service. The Bill of Rights grants every employee the fundamental right to strike. This is an absolute and should always be exercised under certain controlled conditions, as stipulated by the Labour Relations Act 66 of 1995. Convention 87 of the International Labour Organising (ILO) recognises the right of trade unions, as an organisation of workers set up to further and defend their interest (Article 10), to formulate their programs and organise their activities (Article 3); this means that unions have the right to negotiate with employers and to express their views on economic and social issues affecting the occupational interest of their members. This constitutes the position that the right to strike is one of the legitimate and indeed essential means available to workers for furthering and defending their occupational interest. Balanced against the right of every teacher to strike is the right of everyone to have a basic education as set out in section 29 of the Constitution. In terms of section 29(1)(a) everyone has a right, enforceable against the state, to basic education. This creates a strong positive right. Aspects of the right to education are found in human rights treaties and declarations. This right to education is contained in article 26 of the Universal Declaration of Human Rights (1948) which states that “everyone has the right to education”. The International Covenant of Economic, Social and Cultural v Rights of 1966 covers the right to education comprehensively, especially article 13 and 14. In 1989 the Convention on the Rights of the Child further confirmed this right. The right to a basic education is further enhanced by section 28(2) of the Constitution “(a) child‟s best interest is of paramount importance in every matter concerning the child”. It is significant to note that in 2007 the Constitutional Court elevated the “best interest” principle to a right. This implies that the best interest of the child would be the decisive factor in each matter that affects the child. In deciding to declare the teaching profession as an essential service constitutional rights must be balanced. These are the right to strike, the right to a basic education and the best interest of the child principle.
- Full Text:
- Date Issued: 2011
- Authors: Adams, Anton John
- Date: 2011
- Subjects: Educational law and legislation -- South Africa , Teachers -- Legal status, laws, etc. -- South Africa , Right to education -- Law and legislation -- South Africa , Basic education -- South Africa , Human rights -- Study and teaching
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:10188 , http://hdl.handle.net/10948/1573 , Educational law and legislation -- South Africa , Teachers -- Legal status, laws, etc. -- South Africa , Right to education -- Law and legislation -- South Africa , Basic education -- South Africa , Human rights -- Study and teaching
- Description: Because of the impact of teacher strikes on education there has been a call to declare the teacher‟s profession an essential service and thus prohibit them from striking. This call was made by the Democratic Alliance (DA). The Democratic Alliance arguments in their application to the Essential Services Committee was based on the fact that education in South Africa is in a crisis and the life-altering inconvenience this caused for children. The combined teacher unions in the Education Labour Relations Council (ELRC) expressed their concerns over the DA‟s call for education to be declared an Essential Service. The Bill of Rights grants every employee the fundamental right to strike. This is an absolute and should always be exercised under certain controlled conditions, as stipulated by the Labour Relations Act 66 of 1995. Convention 87 of the International Labour Organising (ILO) recognises the right of trade unions, as an organisation of workers set up to further and defend their interest (Article 10), to formulate their programs and organise their activities (Article 3); this means that unions have the right to negotiate with employers and to express their views on economic and social issues affecting the occupational interest of their members. This constitutes the position that the right to strike is one of the legitimate and indeed essential means available to workers for furthering and defending their occupational interest. Balanced against the right of every teacher to strike is the right of everyone to have a basic education as set out in section 29 of the Constitution. In terms of section 29(1)(a) everyone has a right, enforceable against the state, to basic education. This creates a strong positive right. Aspects of the right to education are found in human rights treaties and declarations. This right to education is contained in article 26 of the Universal Declaration of Human Rights (1948) which states that “everyone has the right to education”. The International Covenant of Economic, Social and Cultural v Rights of 1966 covers the right to education comprehensively, especially article 13 and 14. In 1989 the Convention on the Rights of the Child further confirmed this right. The right to a basic education is further enhanced by section 28(2) of the Constitution “(a) child‟s best interest is of paramount importance in every matter concerning the child”. It is significant to note that in 2007 the Constitutional Court elevated the “best interest” principle to a right. This implies that the best interest of the child would be the decisive factor in each matter that affects the child. In deciding to declare the teaching profession as an essential service constitutional rights must be balanced. These are the right to strike, the right to a basic education and the best interest of the child principle.
- Full Text:
- Date Issued: 2011
The effect of mussel bed structure on the associated infauna in South Africa and the interaction between mussel and epibiotic barnacles
- Jordaan, Tembisa Nomathamsanqa
- Authors: Jordaan, Tembisa Nomathamsanqa
- Date: 2011
- Subjects: Mytilidae -- South Africa , Mytilus galloprovincialis -- South Africa , Mussel culture -- South Africa , Shellfish culture -- South Africa , Perna -- South Africa , Barnacles -- South Africa , Mussels -- South Africa , Mussels -- Ecology , Barnacles -- Ecology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5675 , http://hdl.handle.net/10962/d1005360 , Mytilidae -- South Africa , Mytilus galloprovincialis -- South Africa , Mussel culture -- South Africa , Shellfish culture -- South Africa , Perna -- South Africa , Barnacles -- South Africa , Mussels -- South Africa , Mussels -- Ecology , Barnacles -- Ecology
- Description: Mussels are important ecological engineers on intertidal rocks where they create habitat that contributes substantially to overall biodiversity. They provide secondary substratum for other free-living, infaunal or epifaunal organisms, and increase the surface area for settlement by densely packing together into complex multilayered beds. The introduction of the alien invasive mussel Mytilus galloprovincialis has extended the upper limit of mussels on the south coast of South Africa, potentially increasing habitat for associated fauna. The aim of this study was to describe the structure of mussel beds, the general biodiversity associated with multi- and monolayered mussel beds of indigenous Perna perna and alien M. galloprovincialis, and to determine the relationship between mussels and epibiotic barnacles. This was done to determine the community structure of associated macrofauna and the role of mussels as biological facilitators. Samples were collected in Plettenberg Bay, South Africa, where M. galloprovincialis dominates the high mussel zone and P. perna the low zone. Three 15 X 15 cm quadrats were scraped off the rock in the high and low zones, and in the mid zone where the two mussel species co-exist. The samples were collected on 3 occasions. In the laboratory mussel-size was measured and sediment trapped within the samples was separated through 75 μm, 1 mm and 5 mm mesh. The macrofauna was sorted from the 1 mm and 5 mm sieves and identified to species level where possible. The epibiotic relationship between mussels and barnacles was assessed by measuring the prevalence and intensity of barnacle infestation and the condition index of infested mussels. Multivariate analysis was used on the mean abundance data of the species for each treatment (Hierarchical clustering, multidimensional scaling, analysis of similarity and similarity of percentages) and ANOVA was used for most of the statistical analyses. Overall, the results showed that tidal height influences the species composition and abundance of associated fauna. While mussel bed layering influenced the accumulation of sediments; it had no significant effect on the associated fauna. Time of collection also had a strong effect. While there was an overlap of species among samples from January, May and March, the principal species contributing to similarity among the March samples were not found in the other two months. The outcomes of this study showed that low shore mussel beds not only supported a higher abundance and diversity of species, but were also the most structurally complex. Although the condition index of mussels did not correlate to the percentage cover of barnacle epibionts, it was also evident that low shore mussels had the highest prevalence. The levels of barnacle infestation (intensity) for each mussel species were highest where it was common and lowest where it was least abundant. This is viewed as a natural artefact of the distribution patterns of P. perna and M. galloprovincialis across the shore. Mussels are more efficient as facilitators on the low mussel zone than the high mussel zone possibly because they provide habitats that are more effective in protecting the associated macrofauna from the effects of competition and predation, than they are at eliminating the effects of physical stress on the high shore. Although mussels create less stressful habitats and protect organisms from the physical stress of the high shore, there are clear limitations in their ability to provide ideal habitats. The biological associations in an ecosystem can be made weak or strong depending on the external abiotic factors and the adaptability of the affected organisms.
- Full Text:
- Date Issued: 2011
- Authors: Jordaan, Tembisa Nomathamsanqa
- Date: 2011
- Subjects: Mytilidae -- South Africa , Mytilus galloprovincialis -- South Africa , Mussel culture -- South Africa , Shellfish culture -- South Africa , Perna -- South Africa , Barnacles -- South Africa , Mussels -- South Africa , Mussels -- Ecology , Barnacles -- Ecology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5675 , http://hdl.handle.net/10962/d1005360 , Mytilidae -- South Africa , Mytilus galloprovincialis -- South Africa , Mussel culture -- South Africa , Shellfish culture -- South Africa , Perna -- South Africa , Barnacles -- South Africa , Mussels -- South Africa , Mussels -- Ecology , Barnacles -- Ecology
- Description: Mussels are important ecological engineers on intertidal rocks where they create habitat that contributes substantially to overall biodiversity. They provide secondary substratum for other free-living, infaunal or epifaunal organisms, and increase the surface area for settlement by densely packing together into complex multilayered beds. The introduction of the alien invasive mussel Mytilus galloprovincialis has extended the upper limit of mussels on the south coast of South Africa, potentially increasing habitat for associated fauna. The aim of this study was to describe the structure of mussel beds, the general biodiversity associated with multi- and monolayered mussel beds of indigenous Perna perna and alien M. galloprovincialis, and to determine the relationship between mussels and epibiotic barnacles. This was done to determine the community structure of associated macrofauna and the role of mussels as biological facilitators. Samples were collected in Plettenberg Bay, South Africa, where M. galloprovincialis dominates the high mussel zone and P. perna the low zone. Three 15 X 15 cm quadrats were scraped off the rock in the high and low zones, and in the mid zone where the two mussel species co-exist. The samples were collected on 3 occasions. In the laboratory mussel-size was measured and sediment trapped within the samples was separated through 75 μm, 1 mm and 5 mm mesh. The macrofauna was sorted from the 1 mm and 5 mm sieves and identified to species level where possible. The epibiotic relationship between mussels and barnacles was assessed by measuring the prevalence and intensity of barnacle infestation and the condition index of infested mussels. Multivariate analysis was used on the mean abundance data of the species for each treatment (Hierarchical clustering, multidimensional scaling, analysis of similarity and similarity of percentages) and ANOVA was used for most of the statistical analyses. Overall, the results showed that tidal height influences the species composition and abundance of associated fauna. While mussel bed layering influenced the accumulation of sediments; it had no significant effect on the associated fauna. Time of collection also had a strong effect. While there was an overlap of species among samples from January, May and March, the principal species contributing to similarity among the March samples were not found in the other two months. The outcomes of this study showed that low shore mussel beds not only supported a higher abundance and diversity of species, but were also the most structurally complex. Although the condition index of mussels did not correlate to the percentage cover of barnacle epibionts, it was also evident that low shore mussels had the highest prevalence. The levels of barnacle infestation (intensity) for each mussel species were highest where it was common and lowest where it was least abundant. This is viewed as a natural artefact of the distribution patterns of P. perna and M. galloprovincialis across the shore. Mussels are more efficient as facilitators on the low mussel zone than the high mussel zone possibly because they provide habitats that are more effective in protecting the associated macrofauna from the effects of competition and predation, than they are at eliminating the effects of physical stress on the high shore. Although mussels create less stressful habitats and protect organisms from the physical stress of the high shore, there are clear limitations in their ability to provide ideal habitats. The biological associations in an ecosystem can be made weak or strong depending on the external abiotic factors and the adaptability of the affected organisms.
- Full Text:
- Date Issued: 2011
The effectiveness of livestock guarding dogs for livestock production and conservation in Namibia
- Authors: Potgieter, Gail Christine
- Date: 2011
- Subjects: Livestock protection dogs -- Namibia , Herding dogs -- Namibia , Livestock -- Predators of -- Control -- Namibia , Livestock -- Losses -- Namibia
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10680 , http://hdl.handle.net/10948/1666 , Livestock protection dogs -- Namibia , Herding dogs -- Namibia , Livestock -- Predators of -- Control -- Namibia , Livestock -- Losses -- Namibia
- Description: The use of livestock guarding dogs (LGDs) to mitigate farmer-predator conflict in Namibia was evaluated. As farmer-predator conflict has two sides, LGDs were evaluated in terms of livestock production and conservation. The main objectives in terms of livestock production were to document: 1) the perceived ability of LGDs to reduce livestock losses in a cost-effective manner; 2) the farmers’ satisfaction with LGD performance; and 3) factors influencing LGD behaviour. The main objectives in terms of conservation were to record: 1) predator killing by farmers relative to LGD introduction; 2) direct impacts of LGDs on target (damage-causing) species; and 3) the impact of LGDs on non-target species. This evaluation was conducted on LGDs bred by the Cheetah Conservation Fund (CCF) and placed on farms in Namibia. The data were collected during face-to-face interviews with farmers using LGDs. Historical data from the CCF programme were used in conjunction with a complete survey of the farmers in the CCF LGD programme during 2009-2010. In terms of livestock production, 91 percent of the LGDs (n = 65) eliminated or reduced livestock losses. Subsequently, 73 percent of the farmers perceived their LGDs as economically beneficial, although a cost-benefit analysis showed that only 59 percent of the LGDs were cost-effective. Farmers were generally satisfied with the performance of their LGDs. However, farmer satisfaction was more closely linked to good LGD behaviour than the perceived reduction in livestock losses. The most commonly-reported LGD behavioural problems (n = 195) were staying at home rather than accompanying the livestock (21 percent) and chasing wildlife (19 percent). LGD staying home behaviour was linked to a lack of care on subsistence farms, as high quality dog food was not consistently provided. Care for LGDs declined with LGD age on subsistence, but not commercial, farms. In terms of conservation, predator-killing farmers killed fewer individuals in the year since LGD introduction than previously; this result was only significant for black-backed jackal Canis mesomelas. However, 37 LGDs killed jackals, nine killed baboons Papio ursinus, three killed caracals Caracal caracal and one killed a cheetah Acinonyx jubatus (n = 83). Farmers and LGDs combined killed significantly more jackals in the survey year than the same farmers (n = 36) killed before LGD introduction. Conversely, five farmers killed 3.2 ± 2.01 cheetahs each in the year before LGD introduction, whereas LGDs and these farmers combined killed only 0.2 ± 0.2 cheetahs per farm in the survey year. Only 16 LGDs (n = 83) killed non-target species. The high LGD success rate in terms of livestock production was facilitated by livestock husbandry practices in the study area. In terms of conservation, LGDs were more beneficial for apex predators than for mesopredators and had a minor impact on non-target species.
- Full Text:
- Date Issued: 2011
- Authors: Potgieter, Gail Christine
- Date: 2011
- Subjects: Livestock protection dogs -- Namibia , Herding dogs -- Namibia , Livestock -- Predators of -- Control -- Namibia , Livestock -- Losses -- Namibia
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10680 , http://hdl.handle.net/10948/1666 , Livestock protection dogs -- Namibia , Herding dogs -- Namibia , Livestock -- Predators of -- Control -- Namibia , Livestock -- Losses -- Namibia
- Description: The use of livestock guarding dogs (LGDs) to mitigate farmer-predator conflict in Namibia was evaluated. As farmer-predator conflict has two sides, LGDs were evaluated in terms of livestock production and conservation. The main objectives in terms of livestock production were to document: 1) the perceived ability of LGDs to reduce livestock losses in a cost-effective manner; 2) the farmers’ satisfaction with LGD performance; and 3) factors influencing LGD behaviour. The main objectives in terms of conservation were to record: 1) predator killing by farmers relative to LGD introduction; 2) direct impacts of LGDs on target (damage-causing) species; and 3) the impact of LGDs on non-target species. This evaluation was conducted on LGDs bred by the Cheetah Conservation Fund (CCF) and placed on farms in Namibia. The data were collected during face-to-face interviews with farmers using LGDs. Historical data from the CCF programme were used in conjunction with a complete survey of the farmers in the CCF LGD programme during 2009-2010. In terms of livestock production, 91 percent of the LGDs (n = 65) eliminated or reduced livestock losses. Subsequently, 73 percent of the farmers perceived their LGDs as economically beneficial, although a cost-benefit analysis showed that only 59 percent of the LGDs were cost-effective. Farmers were generally satisfied with the performance of their LGDs. However, farmer satisfaction was more closely linked to good LGD behaviour than the perceived reduction in livestock losses. The most commonly-reported LGD behavioural problems (n = 195) were staying at home rather than accompanying the livestock (21 percent) and chasing wildlife (19 percent). LGD staying home behaviour was linked to a lack of care on subsistence farms, as high quality dog food was not consistently provided. Care for LGDs declined with LGD age on subsistence, but not commercial, farms. In terms of conservation, predator-killing farmers killed fewer individuals in the year since LGD introduction than previously; this result was only significant for black-backed jackal Canis mesomelas. However, 37 LGDs killed jackals, nine killed baboons Papio ursinus, three killed caracals Caracal caracal and one killed a cheetah Acinonyx jubatus (n = 83). Farmers and LGDs combined killed significantly more jackals in the survey year than the same farmers (n = 36) killed before LGD introduction. Conversely, five farmers killed 3.2 ± 2.01 cheetahs each in the year before LGD introduction, whereas LGDs and these farmers combined killed only 0.2 ± 0.2 cheetahs per farm in the survey year. Only 16 LGDs (n = 83) killed non-target species. The high LGD success rate in terms of livestock production was facilitated by livestock husbandry practices in the study area. In terms of conservation, LGDs were more beneficial for apex predators than for mesopredators and had a minor impact on non-target species.
- Full Text:
- Date Issued: 2011
The effectiveness of poverty alleviation initiatives in Buffalo City Metropolitan municipality
- Authors: Benya, Zoliswa (Nqolase)
- Date: 2011
- Subjects: Poverty -- South Africa -- Eastern Cape , Economic development projects -- South Africa -- Eastern Cape , Poverty -- Government policy -- South Africa -- Eastern Cape , Economic assistance, Domestic -- South Africa -- Eastern Cape , Squatter settlements -- South Africa -- Eastern Cape , Poor -- Services for
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9048 , http://hdl.handle.net/10948/1613 , Poverty -- South Africa -- Eastern Cape , Economic development projects -- South Africa -- Eastern Cape , Poverty -- Government policy -- South Africa -- Eastern Cape , Economic assistance, Domestic -- South Africa -- Eastern Cape , Squatter settlements -- South Africa -- Eastern Cape , Poor -- Services for
- Description: The South African democratic government has, since 1994, implemented various programs that aim to alleviate poverty through policy interventions. The Provincial Growth and Development Plan (Eastern Cape 2004-2014) commit its self to halving poverty by 2014. The research seeks to evaluate the effectiveness of poverty alleviation initiatives in Buffalo City Metropolitan Municipality (BCMM), East London; focussing in Nompumelelo informal settlement. The study applied quantitative and qualitative approaches for biographical and socio economic information; and for in-depth understanding and verification respectively. Data collection was through structured interviews and survey questionnaires. The findings reveal that there are random, short-term poverty alleviation initiatives taking place in Nompumelelo informal settlement area. Projects that could have been self-sustaining collapsed due to lack of skills and training. The study indicates that the level of unemployment is high at 68 percent.
- Full Text:
- Date Issued: 2011
- Authors: Benya, Zoliswa (Nqolase)
- Date: 2011
- Subjects: Poverty -- South Africa -- Eastern Cape , Economic development projects -- South Africa -- Eastern Cape , Poverty -- Government policy -- South Africa -- Eastern Cape , Economic assistance, Domestic -- South Africa -- Eastern Cape , Squatter settlements -- South Africa -- Eastern Cape , Poor -- Services for
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9048 , http://hdl.handle.net/10948/1613 , Poverty -- South Africa -- Eastern Cape , Economic development projects -- South Africa -- Eastern Cape , Poverty -- Government policy -- South Africa -- Eastern Cape , Economic assistance, Domestic -- South Africa -- Eastern Cape , Squatter settlements -- South Africa -- Eastern Cape , Poor -- Services for
- Description: The South African democratic government has, since 1994, implemented various programs that aim to alleviate poverty through policy interventions. The Provincial Growth and Development Plan (Eastern Cape 2004-2014) commit its self to halving poverty by 2014. The research seeks to evaluate the effectiveness of poverty alleviation initiatives in Buffalo City Metropolitan Municipality (BCMM), East London; focussing in Nompumelelo informal settlement. The study applied quantitative and qualitative approaches for biographical and socio economic information; and for in-depth understanding and verification respectively. Data collection was through structured interviews and survey questionnaires. The findings reveal that there are random, short-term poverty alleviation initiatives taking place in Nompumelelo informal settlement area. Projects that could have been self-sustaining collapsed due to lack of skills and training. The study indicates that the level of unemployment is high at 68 percent.
- Full Text:
- Date Issued: 2011
The effectiveness of productivity improvement initiatives at the Eberspacher Port Elizabeth manufacturing plant : an empirical study
- Authors: Zerbst, Nicolaas Jacobus
- Date: 2011
- Subjects: Industrial productivity , Manufacturing industries -- Labor productivity -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8782 , http://hdl.handle.net/10948/d1013009
- Description: Manufacturing in South Africa constantly face competition from both local as well as foreign entities. Productivity growth is viewed by many executives and business leaders as the key element in maintaining competitiveness in the global economy. The success of the South African manufacturing and its global competitiveness lie in its productivity. By focusing on promoting productivity, South African manufacturers will establish a source of sustained competitive gains, while labour will establish a sustainable source of income growth. The Eberspacher South Africa Port Elizabeth (ESA) is not in any way immune to the level of competition that impacts all businesses in South Africa. ESA not only competeswith other local catalytic converter companies in terms of a high level of productivity, but also with other manufacturing plants within the Eberspacher Group globally. In Eberspacher all exhaust manufacturing plants are constantly benchmarked, comparing productivity levels, quality levels, cost and delivery. This data is used not only to determine goals, but also forms a key determinant as to where any new business is placed. The internal competition encourages all manufacturing plants within Eberspacher to continously improve plant productivity within group. A company is competitive if it is able to produce products that are either cheaper or better than those of other firms. Most of ESA customers are internal final assembly plants from Europe, USA, India and China. ESA therefore constantly have to ensure that they are competitive in all aspects of business, including productivity. In ESA, the overall productivity performance of the manufacturing plant is of utmost importance to ensure the ability to supply all the customers with cost competitive products, at the right time and with zero defects. Productivity in Eberspacher is used as a vital measurement to the sourcing decision for any new business awarded to the group. The main purpose of this study is to determine the effectiveness of productivity improvement initiatives at the Eberspacher Port Elizabeth Manufacturing Plant.
- Full Text:
- Date Issued: 2011
- Authors: Zerbst, Nicolaas Jacobus
- Date: 2011
- Subjects: Industrial productivity , Manufacturing industries -- Labor productivity -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8782 , http://hdl.handle.net/10948/d1013009
- Description: Manufacturing in South Africa constantly face competition from both local as well as foreign entities. Productivity growth is viewed by many executives and business leaders as the key element in maintaining competitiveness in the global economy. The success of the South African manufacturing and its global competitiveness lie in its productivity. By focusing on promoting productivity, South African manufacturers will establish a source of sustained competitive gains, while labour will establish a sustainable source of income growth. The Eberspacher South Africa Port Elizabeth (ESA) is not in any way immune to the level of competition that impacts all businesses in South Africa. ESA not only competeswith other local catalytic converter companies in terms of a high level of productivity, but also with other manufacturing plants within the Eberspacher Group globally. In Eberspacher all exhaust manufacturing plants are constantly benchmarked, comparing productivity levels, quality levels, cost and delivery. This data is used not only to determine goals, but also forms a key determinant as to where any new business is placed. The internal competition encourages all manufacturing plants within Eberspacher to continously improve plant productivity within group. A company is competitive if it is able to produce products that are either cheaper or better than those of other firms. Most of ESA customers are internal final assembly plants from Europe, USA, India and China. ESA therefore constantly have to ensure that they are competitive in all aspects of business, including productivity. In ESA, the overall productivity performance of the manufacturing plant is of utmost importance to ensure the ability to supply all the customers with cost competitive products, at the right time and with zero defects. Productivity in Eberspacher is used as a vital measurement to the sourcing decision for any new business awarded to the group. The main purpose of this study is to determine the effectiveness of productivity improvement initiatives at the Eberspacher Port Elizabeth Manufacturing Plant.
- Full Text:
- Date Issued: 2011