Antibacterial properties of the methanol extract of helichrysum pedunculatum
- Authors: Ncube, Nqobile S
- Date: 2008
- Subjects: Medicinal plants , Methanol , Helichrysum
- Language: English
- Type: Thesis , Masters , MSc (Microbiology)
- Identifier: vital:11241 , http://hdl.handle.net/10353/461 , Medicinal plants , Methanol , Helichrysum
- Description: The methanol extract of Helichrisum pedunculatum was screened for antimicrobial activity up to a concentration of 5 mg/ml using the agar dilution technique. A number of test bacterial isolates, comprising both Gram negative and Gram positive organisms were susceptible to the crude extract of the plant. The minimum inhibitory concentrations (MICs) of the extract ranged between 1 and 5 mg/ml for the susceptible organisms. The MICs of the selected antibiotics, chloramphenicol and penicillin, ranged between 2 and 4 mg/L, and 2 and 32 mg/L respectively against Bacillus cereus, Proteus vulgaris and Staphylococcus aureus OKOH1. Bactericidal activity was determined by the time kill assay. The methanol extract of the plant was not bactericidal at 1 × MIC for B. cereus, P. vulgaris and Staph. aureus OKOH1. At 2 × MIC the extract was bacteriostatic against B. cereus but bactericidal against P. vulgaris and Staph. aureus OKOH1. Combination studies were done at 1/2 × MIC, 1 × MIC and 2 × MIC of the plant extract with 1 × MIC of the antibiotics. Combinations of the plant extract and chloramphenicol resulted in mostly indifferent interactions against P. vulgaris and Staph. aureus OKOH1 but synergistic interactions at higher concentration of the plant extract for B. cereus. Penicillin combinations gave synergistic interactions at lower concentrations of the plant for P.vulgaris and Staph. aureus OKOH1 but was mostly indifferent for B. cereus.
- Full Text:
- Date Issued: 2008
- Authors: Ncube, Nqobile S
- Date: 2008
- Subjects: Medicinal plants , Methanol , Helichrysum
- Language: English
- Type: Thesis , Masters , MSc (Microbiology)
- Identifier: vital:11241 , http://hdl.handle.net/10353/461 , Medicinal plants , Methanol , Helichrysum
- Description: The methanol extract of Helichrisum pedunculatum was screened for antimicrobial activity up to a concentration of 5 mg/ml using the agar dilution technique. A number of test bacterial isolates, comprising both Gram negative and Gram positive organisms were susceptible to the crude extract of the plant. The minimum inhibitory concentrations (MICs) of the extract ranged between 1 and 5 mg/ml for the susceptible organisms. The MICs of the selected antibiotics, chloramphenicol and penicillin, ranged between 2 and 4 mg/L, and 2 and 32 mg/L respectively against Bacillus cereus, Proteus vulgaris and Staphylococcus aureus OKOH1. Bactericidal activity was determined by the time kill assay. The methanol extract of the plant was not bactericidal at 1 × MIC for B. cereus, P. vulgaris and Staph. aureus OKOH1. At 2 × MIC the extract was bacteriostatic against B. cereus but bactericidal against P. vulgaris and Staph. aureus OKOH1. Combination studies were done at 1/2 × MIC, 1 × MIC and 2 × MIC of the plant extract with 1 × MIC of the antibiotics. Combinations of the plant extract and chloramphenicol resulted in mostly indifferent interactions against P. vulgaris and Staph. aureus OKOH1 but synergistic interactions at higher concentration of the plant extract for B. cereus. Penicillin combinations gave synergistic interactions at lower concentrations of the plant for P.vulgaris and Staph. aureus OKOH1 but was mostly indifferent for B. cereus.
- Full Text:
- Date Issued: 2008
Application of dermal microdialysis and tape stripping methods to determine the bioavailability and/or bioequivalence of topical ketoprofen formulations
- Tettey-Amlalo, Ralph Nii Okai
- Authors: Tettey-Amlalo, Ralph Nii Okai
- Date: 2008
- Subjects: Drugs -- Therapeutic equivalency Transdermal medication High performance liquid chromatography Nonsteroidal anti-inflammatory agents -- Bioavailability Nonsteroidal anti-inflammatory agents -- Effectiveness Nonsteroidal anti-inflammatory agents -- Testing Nonsteroidal anti-inflammatory agents -- Side effects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3796 , http://hdl.handle.net/10962/d1003274
- Description: The widespread acceptance of topical formulations intended for local and/or regional activity has prompted renewed interest in developing a model to determine the bioavailability of drugs in order to establish bioequivalence as a means of evaluating formulation performance of multisource products and also for use during formulation development. Current in vivo techniques such as blister suction and skin biopsy amongst others used to determine the bioavailability and/or bioequivalence of topical formulations are either too invasive to generate appropriate concentration-time profiles or require large numbers of study subjects thereby making the study expensive and time-consuming. Moreover, there are currently no sampling techniques that can demonstrate dermal bioavailability and/or bioequivalence of topical formulations intended for local and/or regional activity. Dermal microdialysis is a relatively new application of microdialysis that permits continuous monitoring of endogenous and/or exogenous solutes in the interstitial fluid. The technique is involves the implantation of semi-permeable membranes which are perfused with an isotonic medium at extremely slow flow rates and collection of microlitre sample volumes containing diffused drugs. Tape stripping, a relatively older technique, has been extensively used in comparative bioavailability studies of various topical formulations. However, due to shortcomings arising from reproducibility and inter-subject variation amongst others, the published FDA guidance outlining the initial protocol was subsequently withdrawn. The incorporation of transepidermal water loss with tape stripping has garnered renewed interest and has been used for the determination of drug bioavailability from a number of topical formulations. Hence the primary objective of this research is to develop and evaluate microdialysis sampling and tape stripping techniques, including the incorporation of the determination of transepidermal water loss, to assess the dermal bioavailability of ketoprofen from topical gel formulations and to develop models for bioequivalence assessment. A rapid UPLC-MS/MS method with requisite sensitivity for the analysis of samples generated from dermal microdialysis was developed and validated which accommodated the microlitre sample volumes collected. An HPLC-UV method was developed and validated for the analysis of samples generated from the in vitro microdialysis and in vivo tape stripping studies. The work presented herein contributes to a growing body of scientific knowledge seeking to develop a model for the determination of bioequivalence of pharmaceutically equivalent topical formulations intended for local and/or regional activity in human subjects.
- Full Text:
- Date Issued: 2008
- Authors: Tettey-Amlalo, Ralph Nii Okai
- Date: 2008
- Subjects: Drugs -- Therapeutic equivalency Transdermal medication High performance liquid chromatography Nonsteroidal anti-inflammatory agents -- Bioavailability Nonsteroidal anti-inflammatory agents -- Effectiveness Nonsteroidal anti-inflammatory agents -- Testing Nonsteroidal anti-inflammatory agents -- Side effects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3796 , http://hdl.handle.net/10962/d1003274
- Description: The widespread acceptance of topical formulations intended for local and/or regional activity has prompted renewed interest in developing a model to determine the bioavailability of drugs in order to establish bioequivalence as a means of evaluating formulation performance of multisource products and also for use during formulation development. Current in vivo techniques such as blister suction and skin biopsy amongst others used to determine the bioavailability and/or bioequivalence of topical formulations are either too invasive to generate appropriate concentration-time profiles or require large numbers of study subjects thereby making the study expensive and time-consuming. Moreover, there are currently no sampling techniques that can demonstrate dermal bioavailability and/or bioequivalence of topical formulations intended for local and/or regional activity. Dermal microdialysis is a relatively new application of microdialysis that permits continuous monitoring of endogenous and/or exogenous solutes in the interstitial fluid. The technique is involves the implantation of semi-permeable membranes which are perfused with an isotonic medium at extremely slow flow rates and collection of microlitre sample volumes containing diffused drugs. Tape stripping, a relatively older technique, has been extensively used in comparative bioavailability studies of various topical formulations. However, due to shortcomings arising from reproducibility and inter-subject variation amongst others, the published FDA guidance outlining the initial protocol was subsequently withdrawn. The incorporation of transepidermal water loss with tape stripping has garnered renewed interest and has been used for the determination of drug bioavailability from a number of topical formulations. Hence the primary objective of this research is to develop and evaluate microdialysis sampling and tape stripping techniques, including the incorporation of the determination of transepidermal water loss, to assess the dermal bioavailability of ketoprofen from topical gel formulations and to develop models for bioequivalence assessment. A rapid UPLC-MS/MS method with requisite sensitivity for the analysis of samples generated from dermal microdialysis was developed and validated which accommodated the microlitre sample volumes collected. An HPLC-UV method was developed and validated for the analysis of samples generated from the in vitro microdialysis and in vivo tape stripping studies. The work presented herein contributes to a growing body of scientific knowledge seeking to develop a model for the determination of bioequivalence of pharmaceutically equivalent topical formulations intended for local and/or regional activity in human subjects.
- Full Text:
- Date Issued: 2008
Application of satellite-derived rainfall estimates to extend water resource simulation modelling in South Africa
- Sawunyama, Tendai, Hughes, Denis A
- Authors: Sawunyama, Tendai , Hughes, Denis A
- Date: 2008
- Language: English
- Type: text , Article
- Identifier: vital:7089 , http://hdl.handle.net/10962/d1012419
- Description: Spatially interpolated rainfall estimates from rain-gauges are widely used as input to hydrological models, but deriving accurate estimates at appropriate space and time scales remain a major problem. In South Africa there has been a gradual decrease in the number of active rain-gauges over time. Satellite-based estimates of spatial rainfall are becoming more readily available and offer a viable substitute. The paper presents the potential of using Climate Prediction Center African daily precipitation climatology (CPCAPC) satellite-based datasets (2001-2006) to drive a Pitman hydrological model which has been calibrated using gauge-based rainfall data (1920-1990). However, if two sources of rainfall data are to be used together, it is necessary to ensure that they are compatible in terms of their statistical properties. A non-linear frequency of exceedance transformation technique was used to correct the satellite data to be more consistent with historical spatial rainfall estimates. The technique generated simulation results for the 2001 to 2006 period that were greatly improved compared to the direct use of the untransformed satellite data. While there remain some further questions about the use of satellite-derived rainfall data in different parts of the country, they do seem to have the potential to contribute to extending water resource modelling into the future.
- Full Text:
- Date Issued: 2008
- Authors: Sawunyama, Tendai , Hughes, Denis A
- Date: 2008
- Language: English
- Type: text , Article
- Identifier: vital:7089 , http://hdl.handle.net/10962/d1012419
- Description: Spatially interpolated rainfall estimates from rain-gauges are widely used as input to hydrological models, but deriving accurate estimates at appropriate space and time scales remain a major problem. In South Africa there has been a gradual decrease in the number of active rain-gauges over time. Satellite-based estimates of spatial rainfall are becoming more readily available and offer a viable substitute. The paper presents the potential of using Climate Prediction Center African daily precipitation climatology (CPCAPC) satellite-based datasets (2001-2006) to drive a Pitman hydrological model which has been calibrated using gauge-based rainfall data (1920-1990). However, if two sources of rainfall data are to be used together, it is necessary to ensure that they are compatible in terms of their statistical properties. A non-linear frequency of exceedance transformation technique was used to correct the satellite data to be more consistent with historical spatial rainfall estimates. The technique generated simulation results for the 2001 to 2006 period that were greatly improved compared to the direct use of the untransformed satellite data. While there remain some further questions about the use of satellite-derived rainfall data in different parts of the country, they do seem to have the potential to contribute to extending water resource modelling into the future.
- Full Text:
- Date Issued: 2008
Application of the Baylis-Hillman methodology in the construction of novel heterocyclic derivatives
- Authors: Nyoni, Dubekile
- Date: 2008
- Subjects: Heterocyclic compounds -- Derivatives
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4402 , http://hdl.handle.net/10962/d1006704
- Description: Baylis-Hillman reactions of 2,2’-dithiodibenzaldehyde with the acyclic alkenes, methyl vinyl ketone (MVK) and methyl acrylate have afforded the thiochromene derivatives in moderate yields, and this approach has been extended to the use of the cyclic alkenes, 2-cyclohexenone and 2-cyclopentenone to afford the tricyclic analogues. In all cases, reduction of the disulphide link and intramolecular cyclisation occurred in situ, and a preliminary kinetic study of this reaction using the acyclic substrates MVK and methyl acrylate was undertaken with the aim of elucidating the mechanism involved. The results obtained showed that the consumption of both 2,2’-dithiodibenzaldehyde and MVK and/or methyl acrylate followed 1st-order kinetics during the initial stages of the reaction, but then deviated from 1st-order linearity. The reaction with methyl acrylate was much slower than with MVK, and the kinetic data indicates the mechanism to be more complex than anticipated. Conjugate addition reactions of methyl acrylate-derived 2-nitrobenzaldehyde Baylis-Hillman adducts with the amines, piperidine and benzylamine, afforded a range of conjugate addition products as diastereomeric mixtures in excellent yield (80-100%). Catalytic hydrogenation of the conjugate addition products using a Pd-C catalyst in ethanol, has afforded the corresponding, novel 3-amino-2-quinolone derivatives in lower yield (22-37%).The application of [superscript 13]C NMR prediction programmes to selected compounds synthesized in this study has revealed reasonable correlations between the experimental and predicted values.
- Full Text:
- Date Issued: 2008
- Authors: Nyoni, Dubekile
- Date: 2008
- Subjects: Heterocyclic compounds -- Derivatives
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4402 , http://hdl.handle.net/10962/d1006704
- Description: Baylis-Hillman reactions of 2,2’-dithiodibenzaldehyde with the acyclic alkenes, methyl vinyl ketone (MVK) and methyl acrylate have afforded the thiochromene derivatives in moderate yields, and this approach has been extended to the use of the cyclic alkenes, 2-cyclohexenone and 2-cyclopentenone to afford the tricyclic analogues. In all cases, reduction of the disulphide link and intramolecular cyclisation occurred in situ, and a preliminary kinetic study of this reaction using the acyclic substrates MVK and methyl acrylate was undertaken with the aim of elucidating the mechanism involved. The results obtained showed that the consumption of both 2,2’-dithiodibenzaldehyde and MVK and/or methyl acrylate followed 1st-order kinetics during the initial stages of the reaction, but then deviated from 1st-order linearity. The reaction with methyl acrylate was much slower than with MVK, and the kinetic data indicates the mechanism to be more complex than anticipated. Conjugate addition reactions of methyl acrylate-derived 2-nitrobenzaldehyde Baylis-Hillman adducts with the amines, piperidine and benzylamine, afforded a range of conjugate addition products as diastereomeric mixtures in excellent yield (80-100%). Catalytic hydrogenation of the conjugate addition products using a Pd-C catalyst in ethanol, has afforded the corresponding, novel 3-amino-2-quinolone derivatives in lower yield (22-37%).The application of [superscript 13]C NMR prediction programmes to selected compounds synthesized in this study has revealed reasonable correlations between the experimental and predicted values.
- Full Text:
- Date Issued: 2008
Archdeacon Merriman, ‘Caliban’, and the Cattle-Killing of 1856–57
- Authors: Wright, Laurence
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:7026 , http://hdl.handle.net/10962/d1007212 , http://dx.doi.org/10.1080/00020180802242574
- Description: [From the introduction]: Did Archdeacon Merriman accept that Mhlakaza was Wilhelm Goliath? The short answer is that we don’t know. However, historical problems sometimes yield, or at least buckle slightly, when approached from unusual, tangential perspectives.I believe it can be shown that in the terrible aftermath of the Cattle-Killing, Nathaniel Merriman was brooding on his former servant, Wilhelm Goliath, and that evidence of this preoccupation emerges indirectly in a very open and unexpected forum: a public lecture on Shakespeare.
- Full Text:
- Date Issued: 2008
- Authors: Wright, Laurence
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:7026 , http://hdl.handle.net/10962/d1007212 , http://dx.doi.org/10.1080/00020180802242574
- Description: [From the introduction]: Did Archdeacon Merriman accept that Mhlakaza was Wilhelm Goliath? The short answer is that we don’t know. However, historical problems sometimes yield, or at least buckle slightly, when approached from unusual, tangential perspectives.I believe it can be shown that in the terrible aftermath of the Cattle-Killing, Nathaniel Merriman was brooding on his former servant, Wilhelm Goliath, and that evidence of this preoccupation emerges indirectly in a very open and unexpected forum: a public lecture on Shakespeare.
- Full Text:
- Date Issued: 2008
Aspects of the breeding biology of the African penguin on Bird Island, Algoa Bay
- Authors: Ralph, Mark Shaun
- Date: 2008
- Subjects: Penguins -- South Africa -- Conservation , Penguins -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10716 , http://hdl.handle.net/10948/840 , Penguins -- South Africa -- Conservation , Penguins -- South Africa
- Description: It is important to the survival of the Africa Penguin (Spheniscus demersus) population that breeding at the nest site is successful and that large numbers of chicks are fledged into the breeding population. Nest distribution on Bird Island is not random and locality preferences for breeding exist. Although it seems that sufficient area exists on Bird Island for penguin nests, it can hardly be considered as suitable to optimise breeding. During prolonged heat conditions, breeders relocated to nest sites that were sheltered. Nests that were below ground in burrows was the only habitat that did not suffer nest desertion whilst all the other habitat types (including those that were sheltered) experienced 2-3 fold declines in nest numbers. Nests density and the selection of suitable nest sites are significantly influenced by the stage of breeding that the majority of birds are in, yet nests that are shaded, well-ventilated and protected seem to be the most preferred sites for breeding. Adults that attempt to breed are considered then to be in a healthy condition and will usually lay a double clutch (Randell 1983). The frequency of double clutches being laid during the peak breeding attempt was significantly higher compared to the replacement one. Breeding failure was fairly similar to breeding success during the incubation stage for nests with double clutches however, was substantially higher in single clutches. The growth rate of chicks was best fit to the von Bertalanffy growth curve in 90 percent of the cases. The overall growth rate of chicks from double broods was faster than from single broods, however was not significant. A-chicks maitain a high growth rate until they fledged. Yet, the sibling B-chick recorded the lowest growth rate of the successfully fledged chicks and up to until day 30 recorded a similar weight to those chicks that failed to fledge. Contrary to findings of Randall (1983), chicks from single broods delayed fledging, recorded lowest overall growth rates and experienced the greatest weight loss of all groups, yet fledged successfully. In order for chicks to fledge successfully, they needed to obtain a weight of 1060 g before day 30.5 in their growth cycles to avoid death due to startvation later on. Single chicks that are raised from a double cluth, fledged more other than chicks raised from a single clutch. Unfit or ill-adapted breeders that are marginal in the capabilities of raising offspring, already manifest in a small clutch size and offspring unable to obtain adequate weights during the initial stages of growth.
- Full Text:
- Date Issued: 2008
- Authors: Ralph, Mark Shaun
- Date: 2008
- Subjects: Penguins -- South Africa -- Conservation , Penguins -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10716 , http://hdl.handle.net/10948/840 , Penguins -- South Africa -- Conservation , Penguins -- South Africa
- Description: It is important to the survival of the Africa Penguin (Spheniscus demersus) population that breeding at the nest site is successful and that large numbers of chicks are fledged into the breeding population. Nest distribution on Bird Island is not random and locality preferences for breeding exist. Although it seems that sufficient area exists on Bird Island for penguin nests, it can hardly be considered as suitable to optimise breeding. During prolonged heat conditions, breeders relocated to nest sites that were sheltered. Nests that were below ground in burrows was the only habitat that did not suffer nest desertion whilst all the other habitat types (including those that were sheltered) experienced 2-3 fold declines in nest numbers. Nests density and the selection of suitable nest sites are significantly influenced by the stage of breeding that the majority of birds are in, yet nests that are shaded, well-ventilated and protected seem to be the most preferred sites for breeding. Adults that attempt to breed are considered then to be in a healthy condition and will usually lay a double clutch (Randell 1983). The frequency of double clutches being laid during the peak breeding attempt was significantly higher compared to the replacement one. Breeding failure was fairly similar to breeding success during the incubation stage for nests with double clutches however, was substantially higher in single clutches. The growth rate of chicks was best fit to the von Bertalanffy growth curve in 90 percent of the cases. The overall growth rate of chicks from double broods was faster than from single broods, however was not significant. A-chicks maitain a high growth rate until they fledged. Yet, the sibling B-chick recorded the lowest growth rate of the successfully fledged chicks and up to until day 30 recorded a similar weight to those chicks that failed to fledge. Contrary to findings of Randall (1983), chicks from single broods delayed fledging, recorded lowest overall growth rates and experienced the greatest weight loss of all groups, yet fledged successfully. In order for chicks to fledge successfully, they needed to obtain a weight of 1060 g before day 30.5 in their growth cycles to avoid death due to startvation later on. Single chicks that are raised from a double cluth, fledged more other than chicks raised from a single clutch. Unfit or ill-adapted breeders that are marginal in the capabilities of raising offspring, already manifest in a small clutch size and offspring unable to obtain adequate weights during the initial stages of growth.
- Full Text:
- Date Issued: 2008
Aspects of the thermal ecology of six species of carcass beetles in South Africa
- Authors: Midgley, John Mark
- Date: 2008
- Subjects: Forensic entomology , Diptera -- South Africa , Beetles -- South Africa , Burying beetles , Burying beetles -- South Africa , Beetles -- Effect of temperature on
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5643 , http://hdl.handle.net/10962/d1005325 , Forensic entomology , Diptera -- South Africa , Beetles -- South Africa , Burying beetles , Burying beetles -- South Africa , Beetles -- Effect of temperature on
- Description: The forensic application of entomology is well known, but it is generally a field which concentrates on Diptera. Many Coleoptera also have forensic application, but are generally neglected by forensic entomology researchers. Necrophilic Coleoptera are diverse and therefore have application in estimating Post-Mortem Interval (PMI) by community composition, but they are also valuable in estimating PMI by development. In addition, Coleoptera are more common in stored product cases. Six species of forensically important Coleoptera were studied, three from the family Dermestidae (Dermestes haemorrhoidalis, D. maculatus and D. peruvianus) and three from the family Silphidae (Silpha punctulata, Thanatophilus micans and T. mutilatus). The effect of killing method and storage time on larval length was investigated in T. micans. Coleopteran larvae were shown not to behave in the same way as dipteran larvae. In contrast to dipteran larvae, it is recommended that coleopteran larvae be killed using ethanol. A development model is presented for T. micans. This represents the first statistically robust development model for forensically important Coleoptera, and the first development model for forensically important Silphidae. The model offers a method of estimating PMI which can be used once Diptera are no longer present on a corpse. Upper lethal temperature limits for four species of carcass beetle were determined. A comparison between species shows distinct differentiation between families and species. This differentiation accounts for microhabitat differences which these species show on carcasses. Bioclimatic models for the six species showed contrasting distributions, with both widespread and localised species. These models allow forensic investigators to assess whether the absence of a species from a corpse is forensically significant, or a result of the species distributions. Moisture-related variables were shown to be more important in predicting species distributions than temperature at a regional scale. Forensic entomology standards can be adjusted based on the findings of this study. Length was again shown to be an inferior measurement of larval age. Coleopteran development has been shown to be useful, and should be given greater consideration in future work. T. micans has been shown to be capable of locating and ovipositing on carcasses promptly after death, making it a good forensic indicator. Further work is needed for the full potential of necrophilic Coleoptera to be realised.
- Full Text:
- Date Issued: 2008
- Authors: Midgley, John Mark
- Date: 2008
- Subjects: Forensic entomology , Diptera -- South Africa , Beetles -- South Africa , Burying beetles , Burying beetles -- South Africa , Beetles -- Effect of temperature on
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5643 , http://hdl.handle.net/10962/d1005325 , Forensic entomology , Diptera -- South Africa , Beetles -- South Africa , Burying beetles , Burying beetles -- South Africa , Beetles -- Effect of temperature on
- Description: The forensic application of entomology is well known, but it is generally a field which concentrates on Diptera. Many Coleoptera also have forensic application, but are generally neglected by forensic entomology researchers. Necrophilic Coleoptera are diverse and therefore have application in estimating Post-Mortem Interval (PMI) by community composition, but they are also valuable in estimating PMI by development. In addition, Coleoptera are more common in stored product cases. Six species of forensically important Coleoptera were studied, three from the family Dermestidae (Dermestes haemorrhoidalis, D. maculatus and D. peruvianus) and three from the family Silphidae (Silpha punctulata, Thanatophilus micans and T. mutilatus). The effect of killing method and storage time on larval length was investigated in T. micans. Coleopteran larvae were shown not to behave in the same way as dipteran larvae. In contrast to dipteran larvae, it is recommended that coleopteran larvae be killed using ethanol. A development model is presented for T. micans. This represents the first statistically robust development model for forensically important Coleoptera, and the first development model for forensically important Silphidae. The model offers a method of estimating PMI which can be used once Diptera are no longer present on a corpse. Upper lethal temperature limits for four species of carcass beetle were determined. A comparison between species shows distinct differentiation between families and species. This differentiation accounts for microhabitat differences which these species show on carcasses. Bioclimatic models for the six species showed contrasting distributions, with both widespread and localised species. These models allow forensic investigators to assess whether the absence of a species from a corpse is forensically significant, or a result of the species distributions. Moisture-related variables were shown to be more important in predicting species distributions than temperature at a regional scale. Forensic entomology standards can be adjusted based on the findings of this study. Length was again shown to be an inferior measurement of larval age. Coleopteran development has been shown to be useful, and should be given greater consideration in future work. T. micans has been shown to be capable of locating and ovipositing on carcasses promptly after death, making it a good forensic indicator. Further work is needed for the full potential of necrophilic Coleoptera to be realised.
- Full Text:
- Date Issued: 2008
Assembly of Omegatetravirus virus-like particles in the yeast Saccharomyces cerevisiae
- Authors: Tomasicchio, Michele
- Date: 2008
- Subjects: Helicoverpa armigera Imbrasia cytherea Viruses RNA viruses Insects -- Viruses Lepidoptera -- Viruses Saccharomyces cerevisiae
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3930 , http://hdl.handle.net/10962/d1003989
- Description: The Tetraviridae are a family of ss (+) RNA viruses that specifically infect lepidopteran insects. Their icosahedral capsids are non-enveloped and approximately 40 nm in diameter with T=4 quasi-equivalent symmetry. The omegatetraviruses, which are structurally the best characterised in the family, include Helicoverpa armigera stunt virus (HaSV) and Nudaurelia capensis omega virus (NwV). The omegatetravirus procapsid is composed of 240 identical copies of the capsid precursor proteins, which undergo autoproteolytic cleavage at its carboxyl-terminus generating the mature capsid protein (b) and γ-peptide. This process occurs in vitro following a shift from pH 7.6 to pH 6.0. The viral capsid encapsidates two ss genomic RNAs: The larger RNA1 encodes the viral replicase as well as three small ORFs while RNA2 encodes the capsid precursor protein together with an overlapping ORF designated P17. While a wealth of structural data pertaining to the assembly and maturation of omegatetraviruses is available, little is known about how this relates to their lifecycle. The principle aim of the research described in this thesis was to use an experimental system developed in the yeast, Saccharomyces cerevisiae, to investigate the assembly of HaSV and NwV virus-like particles (VLPs) in terms of maturation and encapsidation of viral RNAs, in vivo. The yeast expression system used two promoter systems for expression of capsid precursor protein: in the first, a hybrid promoter (PGADH) was used for high-level expression, while the second, PGAL1, produced substantially lower levels of the virus capsid protein precursors. An increase in the level of HaSV capsid protein precursor (p71) via the PGADH promoter resulted in a dramatic increase in VLP assembly as compared with the PGAL system. A protein equivalent to the mature capsid protein (p64) appeared at later time intervals following induction of transcription. Transmission electron microscopic studies showed that p64 correlated with the presence of mature VLPs as opposed to procapsids in cells containing p71. This confirmed that the presence of p64 denoted maturation of VLPs in vivo. Further investigation indicated that maturation correlated with cell aging and the onset of apoptosis. It was shown that induction of apoptosis resulted in VLP maturation while inhibition of apoptosis prevented maturation. These results suggested that the process of apoptosis might be the trigger for maturation of virus procapsids in their host cells. The increase in the efficiency of VLP assembly observed in the high-level expression system was proposed to be due to an increase in the cellular concentrations of viral RNA. To test this hypothesis, HaSV P71 was co-expressed with either P71 mRNA or full length RNA2. An increase in the solubility of p71 was observed in cells expressing increased levels of both RNAs, but there was no increase in the efficiency of VLP assembly. Northern analysis of encapsidated RNAs revealed that there was no selective encapsidation of either P71 mRNA or viral RNA2. This data indicated that the increase in viral RNA was not the reason for increased efficiency of VLP assembly, but most likely resulted from higher concentrations of p71 itself. It was decided to determine whether a highly efficient nodavirus replication system developed in yeast for heterologous production of proteins, could be used as a method for expressing the capsid protein precursor. The aim of using this system was to determine if VLPs assembled in a replication system specifically encapsidated viral RNA. Transcripts encoding the NwV capsid protein precursor (p70) were generated in yeast cells by replication of a hybrid RNA template by the Nodamura virus (NoV) replicase. Western analysis confirmed the presence of p70 as well as a protein of 62 kDa corresponding to the mature NwV capsid protein. Northern analysis of purified VLPs showed that NoV RNA1 and RNA3 were encapsidated, but no RNA2 was detected. Taken together, the data lead to the conclusion that specific encapsidation of tetraviral RNAs required more than close proximity of the viral RNAs and assembling virus-like particles. Encapsidation specificity in the omegatetraviruses may require additional viral proteins such as p17 during encapsidation or specific viral RNA encapsidation was replication-dependent. Replication-dependent assembly has been shown in the nodaviruses.
- Full Text:
- Date Issued: 2008
- Authors: Tomasicchio, Michele
- Date: 2008
- Subjects: Helicoverpa armigera Imbrasia cytherea Viruses RNA viruses Insects -- Viruses Lepidoptera -- Viruses Saccharomyces cerevisiae
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3930 , http://hdl.handle.net/10962/d1003989
- Description: The Tetraviridae are a family of ss (+) RNA viruses that specifically infect lepidopteran insects. Their icosahedral capsids are non-enveloped and approximately 40 nm in diameter with T=4 quasi-equivalent symmetry. The omegatetraviruses, which are structurally the best characterised in the family, include Helicoverpa armigera stunt virus (HaSV) and Nudaurelia capensis omega virus (NwV). The omegatetravirus procapsid is composed of 240 identical copies of the capsid precursor proteins, which undergo autoproteolytic cleavage at its carboxyl-terminus generating the mature capsid protein (b) and γ-peptide. This process occurs in vitro following a shift from pH 7.6 to pH 6.0. The viral capsid encapsidates two ss genomic RNAs: The larger RNA1 encodes the viral replicase as well as three small ORFs while RNA2 encodes the capsid precursor protein together with an overlapping ORF designated P17. While a wealth of structural data pertaining to the assembly and maturation of omegatetraviruses is available, little is known about how this relates to their lifecycle. The principle aim of the research described in this thesis was to use an experimental system developed in the yeast, Saccharomyces cerevisiae, to investigate the assembly of HaSV and NwV virus-like particles (VLPs) in terms of maturation and encapsidation of viral RNAs, in vivo. The yeast expression system used two promoter systems for expression of capsid precursor protein: in the first, a hybrid promoter (PGADH) was used for high-level expression, while the second, PGAL1, produced substantially lower levels of the virus capsid protein precursors. An increase in the level of HaSV capsid protein precursor (p71) via the PGADH promoter resulted in a dramatic increase in VLP assembly as compared with the PGAL system. A protein equivalent to the mature capsid protein (p64) appeared at later time intervals following induction of transcription. Transmission electron microscopic studies showed that p64 correlated with the presence of mature VLPs as opposed to procapsids in cells containing p71. This confirmed that the presence of p64 denoted maturation of VLPs in vivo. Further investigation indicated that maturation correlated with cell aging and the onset of apoptosis. It was shown that induction of apoptosis resulted in VLP maturation while inhibition of apoptosis prevented maturation. These results suggested that the process of apoptosis might be the trigger for maturation of virus procapsids in their host cells. The increase in the efficiency of VLP assembly observed in the high-level expression system was proposed to be due to an increase in the cellular concentrations of viral RNA. To test this hypothesis, HaSV P71 was co-expressed with either P71 mRNA or full length RNA2. An increase in the solubility of p71 was observed in cells expressing increased levels of both RNAs, but there was no increase in the efficiency of VLP assembly. Northern analysis of encapsidated RNAs revealed that there was no selective encapsidation of either P71 mRNA or viral RNA2. This data indicated that the increase in viral RNA was not the reason for increased efficiency of VLP assembly, but most likely resulted from higher concentrations of p71 itself. It was decided to determine whether a highly efficient nodavirus replication system developed in yeast for heterologous production of proteins, could be used as a method for expressing the capsid protein precursor. The aim of using this system was to determine if VLPs assembled in a replication system specifically encapsidated viral RNA. Transcripts encoding the NwV capsid protein precursor (p70) were generated in yeast cells by replication of a hybrid RNA template by the Nodamura virus (NoV) replicase. Western analysis confirmed the presence of p70 as well as a protein of 62 kDa corresponding to the mature NwV capsid protein. Northern analysis of purified VLPs showed that NoV RNA1 and RNA3 were encapsidated, but no RNA2 was detected. Taken together, the data lead to the conclusion that specific encapsidation of tetraviral RNAs required more than close proximity of the viral RNAs and assembling virus-like particles. Encapsidation specificity in the omegatetraviruses may require additional viral proteins such as p17 during encapsidation or specific viral RNA encapsidation was replication-dependent. Replication-dependent assembly has been shown in the nodaviruses.
- Full Text:
- Date Issued: 2008
Assessing quality management systems of SMME's in the manufacturing sector
- Authors: Prince, Shawn Noel
- Date: 2008
- Subjects: Production management -- Quality control , Quality control -- Manufactures , Small business -- Management -- South Africa , Quality management -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8729 , http://hdl.handle.net/10948/870 , Production management -- Quality control , Quality control -- Manufactures , Small business -- Management -- South Africa , Quality management -- South Africa -- Eastern Cape
- Description: This dissertation summarises an analysis and assessment of the application of Quality Management Systems (QMS) by Small, Medium and Micro Enterprises (SMMEs), in the Engineering Manufacturing Sector of the greater Cape Town Metropolitan area. An outline of the existing hypothesis derived from previous international SMME studies related to the adoption of QMS by SMME’s, the management’s understanding of quality principles, the potential business benefits of QMS and the reasons for implementing Quality Management systems are given as background to the study. The dissertation includes a discussion of literature on the state of QMS in SMMEs, in particular, recent international research literature hypothesising that SMME management lack essential QMS knowledge and that, in general, most SMME’s do not have a QMS and that SMMEs only implement a QMS as a result of contractual pressures / requirements. Also reported are the results and findings of a survey conducted to test the validity of the existing hypotheses amongst a representative sample of Engineering Manufacturing SMMEs registered with the Cape Regional Chamber of Commerce and Industry in the Western Cape. Results of the survey indicate that almost 90 percent, of the companies surveyed had some type of Quality management System, the only two companies that reported not having a QMS, were companies classified as “Micro”, in terms of the National Small business Act. Analysis of the response to the survey concludes that, in general, more than 80 percent of Engineering SMMEs in the Manufacturing Sector have adopted a QMS based on ISO 9001 and that, on average, their management have a medium to high level of understanding of QMS and the associated business benefits. It is also apparent from survey responses, that companies classified as “Micro” in terms of the Small Business Act of 1996, do not see the need for a formal QM system as the owners of these companies consider them too small for a formal QMS. Instead they take direct ownership of their service and product quality in the face of the customer.
- Full Text:
- Date Issued: 2008
- Authors: Prince, Shawn Noel
- Date: 2008
- Subjects: Production management -- Quality control , Quality control -- Manufactures , Small business -- Management -- South Africa , Quality management -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8729 , http://hdl.handle.net/10948/870 , Production management -- Quality control , Quality control -- Manufactures , Small business -- Management -- South Africa , Quality management -- South Africa -- Eastern Cape
- Description: This dissertation summarises an analysis and assessment of the application of Quality Management Systems (QMS) by Small, Medium and Micro Enterprises (SMMEs), in the Engineering Manufacturing Sector of the greater Cape Town Metropolitan area. An outline of the existing hypothesis derived from previous international SMME studies related to the adoption of QMS by SMME’s, the management’s understanding of quality principles, the potential business benefits of QMS and the reasons for implementing Quality Management systems are given as background to the study. The dissertation includes a discussion of literature on the state of QMS in SMMEs, in particular, recent international research literature hypothesising that SMME management lack essential QMS knowledge and that, in general, most SMME’s do not have a QMS and that SMMEs only implement a QMS as a result of contractual pressures / requirements. Also reported are the results and findings of a survey conducted to test the validity of the existing hypotheses amongst a representative sample of Engineering Manufacturing SMMEs registered with the Cape Regional Chamber of Commerce and Industry in the Western Cape. Results of the survey indicate that almost 90 percent, of the companies surveyed had some type of Quality management System, the only two companies that reported not having a QMS, were companies classified as “Micro”, in terms of the National Small business Act. Analysis of the response to the survey concludes that, in general, more than 80 percent of Engineering SMMEs in the Manufacturing Sector have adopted a QMS based on ISO 9001 and that, on average, their management have a medium to high level of understanding of QMS and the associated business benefits. It is also apparent from survey responses, that companies classified as “Micro” in terms of the Small Business Act of 1996, do not see the need for a formal QM system as the owners of these companies consider them too small for a formal QMS. Instead they take direct ownership of their service and product quality in the face of the customer.
- Full Text:
- Date Issued: 2008
Assessing unwanted early sexual experiences: a South African university study
- Authors: Defferary, Tanya E M
- Date: 2008
- Subjects: College students -- Attitudes -- South Africa , College students -- Sexual behavior -- South Africa , Students -- South Africa -- Psychology
- Language: English
- Type: Thesis , Masters , M Soc Sc (Psych)
- Identifier: vital:11603 , http://hdl.handle.net/10353/137 , College students -- Attitudes -- South Africa , College students -- Sexual behavior -- South Africa , Students -- South Africa -- Psychology
- Description: This study assessed the prevalence of unwanted early sexual experiences (UESE), of the first year psychology students at the University of Fort Hare, in East London. Of the participants, 65 (31 percent) indicated that they had been exposed to some form of non-contact (56.9percent) or contact (22.3 prercent) UESE before the age of 16 years. It was found that more male (42.5 percent) than female (25.2 percent) students reported being exposed to an UESE. The most common perpetrator reported by the majority of the participants were friends (52.4 percent). Most respondents reported that they were only exposed to the UESE once (55.6 percent). The study found that females were significantly more bothered than males both at the time of the UESE and at the time of completing the questionnaire. Both male and female participants were more bothered by the UESE at the time of the event than they were at the time of completing the questionnaire, which indicates an abatement of symptoms over time. The results indicate that flashbacks of the UESE were the most bothersome experience for both male and female participants at the time of completing the questionnaire.
- Full Text:
- Date Issued: 2008
- Authors: Defferary, Tanya E M
- Date: 2008
- Subjects: College students -- Attitudes -- South Africa , College students -- Sexual behavior -- South Africa , Students -- South Africa -- Psychology
- Language: English
- Type: Thesis , Masters , M Soc Sc (Psych)
- Identifier: vital:11603 , http://hdl.handle.net/10353/137 , College students -- Attitudes -- South Africa , College students -- Sexual behavior -- South Africa , Students -- South Africa -- Psychology
- Description: This study assessed the prevalence of unwanted early sexual experiences (UESE), of the first year psychology students at the University of Fort Hare, in East London. Of the participants, 65 (31 percent) indicated that they had been exposed to some form of non-contact (56.9percent) or contact (22.3 prercent) UESE before the age of 16 years. It was found that more male (42.5 percent) than female (25.2 percent) students reported being exposed to an UESE. The most common perpetrator reported by the majority of the participants were friends (52.4 percent). Most respondents reported that they were only exposed to the UESE once (55.6 percent). The study found that females were significantly more bothered than males both at the time of the UESE and at the time of completing the questionnaire. Both male and female participants were more bothered by the UESE at the time of the event than they were at the time of completing the questionnaire, which indicates an abatement of symptoms over time. The results indicate that flashbacks of the UESE were the most bothersome experience for both male and female participants at the time of completing the questionnaire.
- Full Text:
- Date Issued: 2008
Assessment of the impact of Mdantsane Urban Renewal Programme 2002-2007
- Authors: Peter, Ntombentle Cordelia
- Date: 2008
- Subjects: Urban renewal -- South Africa -- Eastern Cape , City planning -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MPA
- Identifier: vital:11623 , http://hdl.handle.net/10353/190 , Urban renewal -- South Africa -- Eastern Cape , City planning -- South Africa -- Eastern Cape
- Description: The study sought to assess the impact of the Mdantsane Urban Renewal Programme (MURP) in Buffalo City Municipality from an analytical perspective of policy making, policy implementation, strategies and results of the programme. The aim was to analyse and evaluate the policy and implementation framework underpinning the MURP within the auspices of the national Urban Renewal Programme (URP). During the course of the study, literature was reviewed with the aim of contextualizing the study, especially given the ‘controversies’ associated with urban renewal interventions globally. As far as implementation is concerned, the institutional mechanisms, the cooperative government imperatives and the community perspectives are highlighted and reported on. Lastly, the study also proposed different policy and implementation options, as well as an implementation model. This model is advocated as an option for local government consideration with the aim of resolving the urban renewal problematique.
- Full Text:
- Date Issued: 2008
- Authors: Peter, Ntombentle Cordelia
- Date: 2008
- Subjects: Urban renewal -- South Africa -- Eastern Cape , City planning -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MPA
- Identifier: vital:11623 , http://hdl.handle.net/10353/190 , Urban renewal -- South Africa -- Eastern Cape , City planning -- South Africa -- Eastern Cape
- Description: The study sought to assess the impact of the Mdantsane Urban Renewal Programme (MURP) in Buffalo City Municipality from an analytical perspective of policy making, policy implementation, strategies and results of the programme. The aim was to analyse and evaluate the policy and implementation framework underpinning the MURP within the auspices of the national Urban Renewal Programme (URP). During the course of the study, literature was reviewed with the aim of contextualizing the study, especially given the ‘controversies’ associated with urban renewal interventions globally. As far as implementation is concerned, the institutional mechanisms, the cooperative government imperatives and the community perspectives are highlighted and reported on. Lastly, the study also proposed different policy and implementation options, as well as an implementation model. This model is advocated as an option for local government consideration with the aim of resolving the urban renewal problematique.
- Full Text:
- Date Issued: 2008
ATP mimics as glutamine synthetase inhibitors : an exploratory synthetic study
- Authors: Salisu, Sheriff Tomilola
- Date: 2008
- Subjects: Glutamine synthetase Tuberculosis -- Treatment Tuberculosis -- Chemotherapy Adenosine triphosphate Adenosine triphosphate -- Synthesis Drug development
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4408 , http://hdl.handle.net/10962/d1006715
- Description: Using a mechanism-based approach to drug discovery, efforts have been directed towards developing novel ATP mimics that can act as GS inhibitors. The purine-based systems, adenosine, adenine and allopurinol, were identified as possible scaffolds for potential ATP mimics, while various meta-disubstituted benzenoid compounds, 3-aminobenzonitrile, 3-aminophenol, resorcinol, 3-aminobenzyl alcohol, 3-hydroxybenzoic acid and 3-aminobenzoic acid have been explored as adenine analogues. These compounds were treated with different alkylating and acylating agents. Allylation of all the substrates was achieved using allyl bromide and N-9 alkylation of protected allopurinol was effected using a number of specially prepared Baylis-Hillman adducts. Acylation of the benzenoid precursors with chloroacetyl chloride, acetoxyacetyl chloride, acryloyl chloride and specially prepared 2,3,4,5,6-pentaacetylgluconoyl chloride afforded the corresponding mono- and /or diacylated products in varying yields (4-96%). Elaboration of the alkylated and acylated products has involved the reaction of hydroxy systems with diethyl chloro phosphate and chloro derivatives with triethyl phosphite in Arbuzov-type reactions to afford phosphorylated products. In all cases, products were fully characterized using 1- and 2-D NMR analysis and, where appropriate, high-resolution mass spectrometry. The application of Modgraph and ChemWindow NMR prediction programmes has been explored and the resulting data have been compared with experimental chemical shift assignments to confirm chemical structures and, in some cases, to establish the position of allylation or acylation. Experimental assignments were found to be generally comparable with the Modgraph data, but not always with the ChemWindow values. The docking of selected products in the 'active-site' of GS and their structural homology with ATP, both in their free and bound conformations have been studied using the ACCELERYS Cerius² platform. All the selected ATP mimics exhibit some form of interaction with the 'active-site' residues, and a number of them appear to be promising GS ligands.
- Full Text:
- Date Issued: 2008
- Authors: Salisu, Sheriff Tomilola
- Date: 2008
- Subjects: Glutamine synthetase Tuberculosis -- Treatment Tuberculosis -- Chemotherapy Adenosine triphosphate Adenosine triphosphate -- Synthesis Drug development
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4408 , http://hdl.handle.net/10962/d1006715
- Description: Using a mechanism-based approach to drug discovery, efforts have been directed towards developing novel ATP mimics that can act as GS inhibitors. The purine-based systems, adenosine, adenine and allopurinol, were identified as possible scaffolds for potential ATP mimics, while various meta-disubstituted benzenoid compounds, 3-aminobenzonitrile, 3-aminophenol, resorcinol, 3-aminobenzyl alcohol, 3-hydroxybenzoic acid and 3-aminobenzoic acid have been explored as adenine analogues. These compounds were treated with different alkylating and acylating agents. Allylation of all the substrates was achieved using allyl bromide and N-9 alkylation of protected allopurinol was effected using a number of specially prepared Baylis-Hillman adducts. Acylation of the benzenoid precursors with chloroacetyl chloride, acetoxyacetyl chloride, acryloyl chloride and specially prepared 2,3,4,5,6-pentaacetylgluconoyl chloride afforded the corresponding mono- and /or diacylated products in varying yields (4-96%). Elaboration of the alkylated and acylated products has involved the reaction of hydroxy systems with diethyl chloro phosphate and chloro derivatives with triethyl phosphite in Arbuzov-type reactions to afford phosphorylated products. In all cases, products were fully characterized using 1- and 2-D NMR analysis and, where appropriate, high-resolution mass spectrometry. The application of Modgraph and ChemWindow NMR prediction programmes has been explored and the resulting data have been compared with experimental chemical shift assignments to confirm chemical structures and, in some cases, to establish the position of allylation or acylation. Experimental assignments were found to be generally comparable with the Modgraph data, but not always with the ChemWindow values. The docking of selected products in the 'active-site' of GS and their structural homology with ATP, both in their free and bound conformations have been studied using the ACCELERYS Cerius² platform. All the selected ATP mimics exhibit some form of interaction with the 'active-site' residues, and a number of them appear to be promising GS ligands.
- Full Text:
- Date Issued: 2008
Availability of pharmacoeconomic data and its use in the development of drug formularies in South Africa
- Authors: Keele, Mothobi Godfrey
- Date: 2008
- Subjects: Drugs -- Cost effectiveness , Pharmacy -- Economic aspects
- Language: English
- Type: Thesis , Masters , MPharm
- Identifier: vital:10146 , http://hdl.handle.net/10948/685 , Drugs -- Cost effectiveness , Pharmacy -- Economic aspects
- Description: In an attempt to manage scarce health care resources and keep drug expenditure low, health care administrators worldwide have to make careful considerations regarding the choice of drugs to be provided to patients within their systems. One of the key strategies that is being employed to achieve this goal is the use of formularies. A major challenge in the formulary development process is to use pharmacoeconomics and outcomes research effectively to arrive at formularies that simultaneously provide patients with effective pharmacotherapy whilst maintaining financial stability. The extent to which this can be successfully achieved depends to a large extent on the availability of appropriate pharmacoeconomic data. The primary objectives of this study were to describe the availability and quality of literature pertaining to South African based pharmacoeconomic research, and to establish the manner in and extent to which pharmacoeconomic data is used in drug formulary decision-making processes, in both the private and public health care sectors in South Africa. A structured bibliographic search for South African pharmacoeconomic studies was conducted and a qualitative assessment of the identified studies which met the predetermined inclusion criteria was completed, using a pre-validated quality evaluation tool. In order to determine the use of pharmacoeconomic data in the formulary decisionmaking processes, by various stake holders in both the public and private of health care sectors in South Africa, a cross-sectional, descriptive study using a self-administered questionnaire was conducted. The results suggest that there is a limited availability of pharmacoeconomic research data in South Africa. Only 16 full pharmacoeconomic studies could be identified as having been published between 01 January 1995 and 30 June 2007. The quality of 3 of these studies was considered to be ‘dubious’, one study was found to be of high standard whilst the other 12 (74.95%) were of acceptable quality and thus could be considered as suitable to be used in formulary decision-making. The results of the national survey indicated that pharmacoeconomics is considered to be of importance and is used in formulary decision-making processes in both the public and private sectors. The primary source of pharmacoeconomic data used in formulary decisions appears to be international peer-reviewed publications. Of concern however, is the finding that this data, mostly from studies conducted outside of South Africa, is applied directly without sensitivity analysis or modelling. The results of the literature search and the subsequent quality appraisal suggest that pharmacoeconomic research and the use of pharmacoeconomic data in formulary decisions is at its infancy in South Africa. Thus efforts are needed to develop and grow the discipline of pharmacoeconomics in South Africa.
- Full Text:
- Date Issued: 2008
- Authors: Keele, Mothobi Godfrey
- Date: 2008
- Subjects: Drugs -- Cost effectiveness , Pharmacy -- Economic aspects
- Language: English
- Type: Thesis , Masters , MPharm
- Identifier: vital:10146 , http://hdl.handle.net/10948/685 , Drugs -- Cost effectiveness , Pharmacy -- Economic aspects
- Description: In an attempt to manage scarce health care resources and keep drug expenditure low, health care administrators worldwide have to make careful considerations regarding the choice of drugs to be provided to patients within their systems. One of the key strategies that is being employed to achieve this goal is the use of formularies. A major challenge in the formulary development process is to use pharmacoeconomics and outcomes research effectively to arrive at formularies that simultaneously provide patients with effective pharmacotherapy whilst maintaining financial stability. The extent to which this can be successfully achieved depends to a large extent on the availability of appropriate pharmacoeconomic data. The primary objectives of this study were to describe the availability and quality of literature pertaining to South African based pharmacoeconomic research, and to establish the manner in and extent to which pharmacoeconomic data is used in drug formulary decision-making processes, in both the private and public health care sectors in South Africa. A structured bibliographic search for South African pharmacoeconomic studies was conducted and a qualitative assessment of the identified studies which met the predetermined inclusion criteria was completed, using a pre-validated quality evaluation tool. In order to determine the use of pharmacoeconomic data in the formulary decisionmaking processes, by various stake holders in both the public and private of health care sectors in South Africa, a cross-sectional, descriptive study using a self-administered questionnaire was conducted. The results suggest that there is a limited availability of pharmacoeconomic research data in South Africa. Only 16 full pharmacoeconomic studies could be identified as having been published between 01 January 1995 and 30 June 2007. The quality of 3 of these studies was considered to be ‘dubious’, one study was found to be of high standard whilst the other 12 (74.95%) were of acceptable quality and thus could be considered as suitable to be used in formulary decision-making. The results of the national survey indicated that pharmacoeconomics is considered to be of importance and is used in formulary decision-making processes in both the public and private sectors. The primary source of pharmacoeconomic data used in formulary decisions appears to be international peer-reviewed publications. Of concern however, is the finding that this data, mostly from studies conducted outside of South Africa, is applied directly without sensitivity analysis or modelling. The results of the literature search and the subsequent quality appraisal suggest that pharmacoeconomic research and the use of pharmacoeconomic data in formulary decisions is at its infancy in South Africa. Thus efforts are needed to develop and grow the discipline of pharmacoeconomics in South Africa.
- Full Text:
- Date Issued: 2008
Baited traps may be an alternative to conventional pesticides in the integrated crop management of chicory (Compositae) in South Africa
- Midgley, John M, Hill, Martin P, Villet, Martin H
- Authors: Midgley, John M , Hill, Martin P , Villet, Martin H
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6858 , http://hdl.handle.net/10962/d1011141 , http://dx.doi.org/10.1603/0022-0493(2008)101[99:BTMBAA]2.0.CO;2 , https://orcid.org/0000-0003-0579-5298
- Description: Chicory, Chicorium intybus L. (Compositae), is a major field crop in the Eastern Cape Province of South Africa. Several pests feed on the leaves of the plant, resulting in reduced yield. The most important of these are the noctuid moths Helicoverpa armigera (Hübner), Chrysodeixis acuta (Walker), and Trichoplusia orichalcea (F.). The use of attract-and-kill traps offers an alternative to broad-based insecticides in the control of these species. Three fields were treated with normal insecticides and three fields with yellow-baited traps. Eight additional traps were placed in each field, with half of the traps containing the insecticide 2,2-dichlorovinyl dimethyl phosphate (dichlorvos) and half without dichlorvos; and half yellow and half green. Total moth numbers and nonphytophage diversity were measured from these eight traps. Although no differences in H. armigera or T. orichalcea catches were observed between insecticide- and trap-treated fields, numbers of C. acuta and the total number of moths were significantly higher in insecticide-treated fields. Yellow traps containing dichlorvos contained more moths than yellow traps without dichlorvos, or green traps with dichlorvos, or green traps without dichlorvos; but they also contained more nonphytophagous insects. Yellow traps also enhanced the catches of thrips on card traps associated with them. These results offer an opportunity for the South African chicory industry to reduce pesticide applications and thus mitigate environmental impacts.
- Full Text:
- Date Issued: 2008
- Authors: Midgley, John M , Hill, Martin P , Villet, Martin H
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6858 , http://hdl.handle.net/10962/d1011141 , http://dx.doi.org/10.1603/0022-0493(2008)101[99:BTMBAA]2.0.CO;2 , https://orcid.org/0000-0003-0579-5298
- Description: Chicory, Chicorium intybus L. (Compositae), is a major field crop in the Eastern Cape Province of South Africa. Several pests feed on the leaves of the plant, resulting in reduced yield. The most important of these are the noctuid moths Helicoverpa armigera (Hübner), Chrysodeixis acuta (Walker), and Trichoplusia orichalcea (F.). The use of attract-and-kill traps offers an alternative to broad-based insecticides in the control of these species. Three fields were treated with normal insecticides and three fields with yellow-baited traps. Eight additional traps were placed in each field, with half of the traps containing the insecticide 2,2-dichlorovinyl dimethyl phosphate (dichlorvos) and half without dichlorvos; and half yellow and half green. Total moth numbers and nonphytophage diversity were measured from these eight traps. Although no differences in H. armigera or T. orichalcea catches were observed between insecticide- and trap-treated fields, numbers of C. acuta and the total number of moths were significantly higher in insecticide-treated fields. Yellow traps containing dichlorvos contained more moths than yellow traps without dichlorvos, or green traps with dichlorvos, or green traps without dichlorvos; but they also contained more nonphytophagous insects. Yellow traps also enhanced the catches of thrips on card traps associated with them. These results offer an opportunity for the South African chicory industry to reduce pesticide applications and thus mitigate environmental impacts.
- Full Text:
- Date Issued: 2008
Barriers and drivers to the implementation of the "clean development mechanism" within the Nelson Mandela Bay Municipality: a case study
- Authors: Wilson, Craig Michael
- Date: 2008
- Subjects: Nelson Mandela Metropolitan Municipality (Eastern Cape, South Africa) Local government -- South Africa -- Eastern Cape -- Case studies Climatic changes -- South Africa -- Eastern Cape -- Case studies Greenhouse gases -- Environmental aspects -- South Africa -- Eastern Cape -- Case studies Environmental economics -- South Africa -- Eastern Cape -- Case studies Greenhouse effect, Atmospheric Global warming
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:731 , http://hdl.handle.net/10962/d1003851
- Description: The global threat of climate change is one of the most crucial environmental issues facing the world in modern times. In response to this threat, international governments have drafted the Kyoto Protocol which included the Clean Development Mechanism (CDM). The CDM is a scheme which invited developing countries, like South Africa, to become involved in climate change mitigation projects. While South Africa has been identified as an attractive host country for CDM projects, research has revealed that it lags behind other developing countries in this regard. This study provides a theoretical background to the CDM and grounds the subject within the field of Environmental Economics. Following a literature review of factors that could influence the involvement of a municipality in CDM projects, this thesis undertook a case study of the barriers and drivers to CDM implementation within the Nelson Mandela Bay Municipality (NMBM). Use was made of semi-structured interviews, where a questionnaire was used to guide the researcher’s interview process. Five NMBM officers, who were likely to have been involved with CDM project implementation, were interviewed. Data collected was analyzed using a coding technique and was compared and contrasted to the literature in a process of explanation building. It was possible to elicit 14 factors that acted as CDM-barriers; seven that acted as CDM-drivers; and 10 that were required to change within the NMBM to encourage greater CDM involvement. Of the barriers, lack of awareness, poor political will and lack of funding emerged as the most inhibiting. Of the CDM-drivers, the potential financial benefits; ownership of infrastructure capable of producing carbon assets; and technology transfer emerged as the factors most likely to promote CDM involvement. With regards the factors that require change, it emerged that a positive response would result from a proactive stance by National Government on the CDM; the use of Public-Private-Partnerships to facilitate CDM projects; and improved communication and capacity building within the NMBM and the Nelson Mandela Bay business community. The main recommendation offered to the NMBM was for it to draft a Sustainable Development Policy as well as a formal sustainable development strategy to drive a coherent and consolidated approach to the Municipality’s involvement with CDM projects. Further, it was proposed that the NMBM should, lobby National Government for it to promulgate enabling legislation and a framework which would encourage CDM investment in South Africa; and engage with local business to promote the active involvement of the Nelson Mandela Bay with the implementation of CDM projects. Keywords: Global Warming, Kyoto Protocol, Clean Development Mechanism, Sustainable Development, Environmental Economics, Public Sector, Nelson Mandela Bay Municipality.
- Full Text:
- Date Issued: 2008
- Authors: Wilson, Craig Michael
- Date: 2008
- Subjects: Nelson Mandela Metropolitan Municipality (Eastern Cape, South Africa) Local government -- South Africa -- Eastern Cape -- Case studies Climatic changes -- South Africa -- Eastern Cape -- Case studies Greenhouse gases -- Environmental aspects -- South Africa -- Eastern Cape -- Case studies Environmental economics -- South Africa -- Eastern Cape -- Case studies Greenhouse effect, Atmospheric Global warming
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:731 , http://hdl.handle.net/10962/d1003851
- Description: The global threat of climate change is one of the most crucial environmental issues facing the world in modern times. In response to this threat, international governments have drafted the Kyoto Protocol which included the Clean Development Mechanism (CDM). The CDM is a scheme which invited developing countries, like South Africa, to become involved in climate change mitigation projects. While South Africa has been identified as an attractive host country for CDM projects, research has revealed that it lags behind other developing countries in this regard. This study provides a theoretical background to the CDM and grounds the subject within the field of Environmental Economics. Following a literature review of factors that could influence the involvement of a municipality in CDM projects, this thesis undertook a case study of the barriers and drivers to CDM implementation within the Nelson Mandela Bay Municipality (NMBM). Use was made of semi-structured interviews, where a questionnaire was used to guide the researcher’s interview process. Five NMBM officers, who were likely to have been involved with CDM project implementation, were interviewed. Data collected was analyzed using a coding technique and was compared and contrasted to the literature in a process of explanation building. It was possible to elicit 14 factors that acted as CDM-barriers; seven that acted as CDM-drivers; and 10 that were required to change within the NMBM to encourage greater CDM involvement. Of the barriers, lack of awareness, poor political will and lack of funding emerged as the most inhibiting. Of the CDM-drivers, the potential financial benefits; ownership of infrastructure capable of producing carbon assets; and technology transfer emerged as the factors most likely to promote CDM involvement. With regards the factors that require change, it emerged that a positive response would result from a proactive stance by National Government on the CDM; the use of Public-Private-Partnerships to facilitate CDM projects; and improved communication and capacity building within the NMBM and the Nelson Mandela Bay business community. The main recommendation offered to the NMBM was for it to draft a Sustainable Development Policy as well as a formal sustainable development strategy to drive a coherent and consolidated approach to the Municipality’s involvement with CDM projects. Further, it was proposed that the NMBM should, lobby National Government for it to promulgate enabling legislation and a framework which would encourage CDM investment in South Africa; and engage with local business to promote the active involvement of the Nelson Mandela Bay with the implementation of CDM projects. Keywords: Global Warming, Kyoto Protocol, Clean Development Mechanism, Sustainable Development, Environmental Economics, Public Sector, Nelson Mandela Bay Municipality.
- Full Text:
- Date Issued: 2008
Beneficial effects of medicinal plants in fish diseases
- Stratev, Deyan, Zhelyazkov, Georgi, Noundou, Xavier Siwe, Krause, Rui W M
- Authors: Stratev, Deyan , Zhelyazkov, Georgi , Noundou, Xavier Siwe , Krause, Rui W M
- Date: 2008
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123487 , vital:35447 , https://doi.org/10.1007/s10499-017-0219-x
- Description: Fish are constantly in contact with pathogens inhabiting water. High population density as well as poor hydrodynamic conditions and feeding lead to an increased sensitivity towards infections. In order to prevent major economic losses due to diseases, various medications are used for treatment and prevention of infections. The use of antimicrobial drugs in aquacultures could lead to emergence of resistance in pathogenic microorganisms. Alternatives are being sought over the last few years to replace antibiotics, and medicinal plants are one of available options for this purpose. These plants are rich in secondary metabolites and phytochemical compounds, which have an effect against viral, bacterial, and parasitic diseases in fish. Their main advantage is their natural origin and most of these plants do not represent threat for human health, the fish, and the environment. The goal of this review is to present information on the treatment of viral, bacterial, and parasitic diseases in fish through medicinal plants, with focus on the mechanisms of action of the identified secondary metabolites, fractions, or plant extracts.
- Full Text:
- Date Issued: 2008
- Authors: Stratev, Deyan , Zhelyazkov, Georgi , Noundou, Xavier Siwe , Krause, Rui W M
- Date: 2008
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123487 , vital:35447 , https://doi.org/10.1007/s10499-017-0219-x
- Description: Fish are constantly in contact with pathogens inhabiting water. High population density as well as poor hydrodynamic conditions and feeding lead to an increased sensitivity towards infections. In order to prevent major economic losses due to diseases, various medications are used for treatment and prevention of infections. The use of antimicrobial drugs in aquacultures could lead to emergence of resistance in pathogenic microorganisms. Alternatives are being sought over the last few years to replace antibiotics, and medicinal plants are one of available options for this purpose. These plants are rich in secondary metabolites and phytochemical compounds, which have an effect against viral, bacterial, and parasitic diseases in fish. Their main advantage is their natural origin and most of these plants do not represent threat for human health, the fish, and the environment. The goal of this review is to present information on the treatment of viral, bacterial, and parasitic diseases in fish through medicinal plants, with focus on the mechanisms of action of the identified secondary metabolites, fractions, or plant extracts.
- Full Text:
- Date Issued: 2008
Between hotel mama and petrol station manager: the represatations of women's realities in a selection of African films
- Authors: O'Reilly, Kevin Joseph
- Date: 2008
- Subjects: Motion pictures -- Africa , Women in motion pictures
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:8404 , http://hdl.handle.net/10948/789 , Motion pictures -- Africa , Women in motion pictures
- Description: The roles that women perform as depicted in African films are often dictated to by the type of society they find themselves in. At first glance traditional societies can be seen as oppressive because of the presence of certain cultural practices. Alternatively modern urban settings appear to offer women authority and empowerment through employment. However, with a closer examination one sees that the situation is not so simplistic. Such is the case when certain traditional practices that are deemed oppressive through a Western perspective, are still found in urban societies. Films on the subject of African women have to be cautious not place their characters in stereotypical roles. Therefore, it is not enough to merely portray African women as ‘oppressed’. African films that engage in a feminist critique need to present ‘realistic’ portrayals of African women. Such characters are layered and complex. The film Faat Kine (2000) depicts such a character in the authoritative protagonist Kine. The film La Vie est Belle (1987) examines the issue of polygamous marriages and patriarchy from the point of view of two African women living in France. Touki Bouki (1973) examines two young characters living in Senegal and questions the possibility of escape from ones circumstances. Traditional practices such as polygamous marriages are explored in Xala (1975), and Finzan (1989) explores cultural practices such as forced marriages and female circumcision. This treatise will consider women and work in both traditional society and urban settings. African feminism will also be investigated for the purpose of exploring common social perceptions of women in Africa.
- Full Text:
- Date Issued: 2008
- Authors: O'Reilly, Kevin Joseph
- Date: 2008
- Subjects: Motion pictures -- Africa , Women in motion pictures
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:8404 , http://hdl.handle.net/10948/789 , Motion pictures -- Africa , Women in motion pictures
- Description: The roles that women perform as depicted in African films are often dictated to by the type of society they find themselves in. At first glance traditional societies can be seen as oppressive because of the presence of certain cultural practices. Alternatively modern urban settings appear to offer women authority and empowerment through employment. However, with a closer examination one sees that the situation is not so simplistic. Such is the case when certain traditional practices that are deemed oppressive through a Western perspective, are still found in urban societies. Films on the subject of African women have to be cautious not place their characters in stereotypical roles. Therefore, it is not enough to merely portray African women as ‘oppressed’. African films that engage in a feminist critique need to present ‘realistic’ portrayals of African women. Such characters are layered and complex. The film Faat Kine (2000) depicts such a character in the authoritative protagonist Kine. The film La Vie est Belle (1987) examines the issue of polygamous marriages and patriarchy from the point of view of two African women living in France. Touki Bouki (1973) examines two young characters living in Senegal and questions the possibility of escape from ones circumstances. Traditional practices such as polygamous marriages are explored in Xala (1975), and Finzan (1989) explores cultural practices such as forced marriages and female circumcision. This treatise will consider women and work in both traditional society and urban settings. African feminism will also be investigated for the purpose of exploring common social perceptions of women in Africa.
- Full Text:
- Date Issued: 2008
Biodiversity of Salmonella strains isolated from selected water sources and wastewater discharge points in the Easern Cape Province of South Africa
- Authors: Mafu, Nwabisa Charity
- Date: 2008
- Subjects: Biodiversity conservation -- South Africa -- Eastern Cape , Biodiversity -- South Africa -- Eastern Cape , Salmonella typhimurium
- Language: English
- Type: Thesis , Masters , MSc (Microbiology)
- Identifier: vital:11248 , http://hdl.handle.net/10353/74 , Biodiversity conservation -- South Africa -- Eastern Cape , Biodiversity -- South Africa -- Eastern Cape , Salmonella typhimurium
- Description: In this study, the diversity of forty Salmonella isolates from selected drinking water and wastewater sources in the Eastern Cape Province of South Africa was assessed using parameters such as protein and lipopolysaccharide profile analysis, DNA fingerprinting and antibiotic susceptibility profile as test indices. Wastewater samples from Amalinda, Shornville and Fort Hare wastewater plants, and water samples from Gogogo and Tyume rivers were collected on ice and transported to the laboratory of the department of Microbiology and Biochemistry, University of Fort Hare for processing. The DNA dendograms of Salmonella and the applied UPGMA revealed 4 similarity groups of the strains. Most of the strains recovered from Amalinda, Shornville, Fort Hare wastewater plants, Gogogo and Tyume rivers show a high percentage of genetic similarity. On the other hand, protein dendograms of Salmonella isolates revealed 2 similarity groups which varied widely. Also, the lipopolysaccharide dendograms revealed three similarity groups with the first similarity groups showing a very high relatedness between strains from different water sources. The second similarity group included 16 strains which formed a rather homogenous group, and the third similarity group formed a distinct group. Of the seven antibiotics and sulfonamides tested against the Salmonella species, five namely, neomycin, chloramphenicol, kanamycin, streptomycin and cotrimoxazole were significantly inhibitory, while the bacteria showed considerable resistance to doxycycline and sulphamethoxazole. Our results based on restriction digestion, SDS/PAGE and dendogram construction show that there is a high similarity between the forty Salmonella strains studied, and that these methods are valuable tools for evaluating the relatedness ofSalmonella species. Our observations have proffered a veritable reference point on the diversity of Salmonella strains in the studied area.
- Full Text:
- Date Issued: 2008
- Authors: Mafu, Nwabisa Charity
- Date: 2008
- Subjects: Biodiversity conservation -- South Africa -- Eastern Cape , Biodiversity -- South Africa -- Eastern Cape , Salmonella typhimurium
- Language: English
- Type: Thesis , Masters , MSc (Microbiology)
- Identifier: vital:11248 , http://hdl.handle.net/10353/74 , Biodiversity conservation -- South Africa -- Eastern Cape , Biodiversity -- South Africa -- Eastern Cape , Salmonella typhimurium
- Description: In this study, the diversity of forty Salmonella isolates from selected drinking water and wastewater sources in the Eastern Cape Province of South Africa was assessed using parameters such as protein and lipopolysaccharide profile analysis, DNA fingerprinting and antibiotic susceptibility profile as test indices. Wastewater samples from Amalinda, Shornville and Fort Hare wastewater plants, and water samples from Gogogo and Tyume rivers were collected on ice and transported to the laboratory of the department of Microbiology and Biochemistry, University of Fort Hare for processing. The DNA dendograms of Salmonella and the applied UPGMA revealed 4 similarity groups of the strains. Most of the strains recovered from Amalinda, Shornville, Fort Hare wastewater plants, Gogogo and Tyume rivers show a high percentage of genetic similarity. On the other hand, protein dendograms of Salmonella isolates revealed 2 similarity groups which varied widely. Also, the lipopolysaccharide dendograms revealed three similarity groups with the first similarity groups showing a very high relatedness between strains from different water sources. The second similarity group included 16 strains which formed a rather homogenous group, and the third similarity group formed a distinct group. Of the seven antibiotics and sulfonamides tested against the Salmonella species, five namely, neomycin, chloramphenicol, kanamycin, streptomycin and cotrimoxazole were significantly inhibitory, while the bacteria showed considerable resistance to doxycycline and sulphamethoxazole. Our results based on restriction digestion, SDS/PAGE and dendogram construction show that there is a high similarity between the forty Salmonella strains studied, and that these methods are valuable tools for evaluating the relatedness ofSalmonella species. Our observations have proffered a veritable reference point on the diversity of Salmonella strains in the studied area.
- Full Text:
- Date Issued: 2008
Biological responses to a resumption in river flow in a freshwater-deprived, permanently open Southern African estuary
- Vorwerk, Paul D, Froneman, P William, Paterson, Angus W, Strydom, Nadine A, Whitfield, A K
- Authors: Vorwerk, Paul D , Froneman, P William , Paterson, Angus W , Strydom, Nadine A , Whitfield, A K
- Date: 2008
- Language: English
- Type: text , Article
- Identifier: vital:6886 , http://hdl.handle.net/10962/d1011645
- Description: The Kariega Estuary is a freshwater-deprived system due to numerous impoundments in the catchment. This system has had little or no horizontal salinity gradient over the last 15 years, with hypersaline conditions sometimes predominating in the upper reaches. Following high rainfall events in the catchment during the spring of 2006, including a flood event (approximate 1:10 year) in August 2006, a series of riverine pulses entered the estuary and a horizontal salinity gradient was established. This study examined the influence of this freshwater pulse on four components of the biota within the estuary, namely the zooplankton, and larval, littoral and demersal fishes. The study demonstrated that in three of these components elevated densities were recorded following the riverine input, with only the littoral fishes retaining an almost constant density. In addition, changes in the relative contributions of the estuarine utilisation classes for all three fish groups examined indicated that freshwater input into these systems positively influences the abundances. This has significant implications for water managers as it demonstrates the importance of an Ecological Reserve (defined as ‘the water required to protect the aquatic ecosystems of the water resource’) for this system.
- Full Text:
- Date Issued: 2008
- Authors: Vorwerk, Paul D , Froneman, P William , Paterson, Angus W , Strydom, Nadine A , Whitfield, A K
- Date: 2008
- Language: English
- Type: text , Article
- Identifier: vital:6886 , http://hdl.handle.net/10962/d1011645
- Description: The Kariega Estuary is a freshwater-deprived system due to numerous impoundments in the catchment. This system has had little or no horizontal salinity gradient over the last 15 years, with hypersaline conditions sometimes predominating in the upper reaches. Following high rainfall events in the catchment during the spring of 2006, including a flood event (approximate 1:10 year) in August 2006, a series of riverine pulses entered the estuary and a horizontal salinity gradient was established. This study examined the influence of this freshwater pulse on four components of the biota within the estuary, namely the zooplankton, and larval, littoral and demersal fishes. The study demonstrated that in three of these components elevated densities were recorded following the riverine input, with only the littoral fishes retaining an almost constant density. In addition, changes in the relative contributions of the estuarine utilisation classes for all three fish groups examined indicated that freshwater input into these systems positively influences the abundances. This has significant implications for water managers as it demonstrates the importance of an Ecological Reserve (defined as ‘the water required to protect the aquatic ecosystems of the water resource’) for this system.
- Full Text:
- Date Issued: 2008
Bioprocess development for removal of nitrogenous compounds from precious metal refinery wastewater
- Manipura, Walappuly Mudiyanselage Janakasiri Aruna Shantha Bandara
- Authors: Manipura, Walappuly Mudiyanselage Janakasiri Aruna Shantha Bandara
- Date: 2008
- Subjects: Factory and trade waste Centralized industrial waste treatment facilities Metals -- Absorption and adsorption Metals -- Environmental aspects Water -- Purification -- Mathematical models Water quality management Water reuse Metals -- Refining Microbiology -- Research
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4076 , http://hdl.handle.net/10962/d1007341
- Description: Removal of nitrogenous compounds from precious metal refinery (PMR) wastewater is important in terms of avoiding eutrophication (environmental protection), metal recovery (increased overall process efficiency and value recovery) and reuse of treated water (maximum use of natural resources). Extreme pH conditions (4 to 13 depending on the wastewater stream), high chemical oxygen demand (> 10,000 mg/I), numerous metals and high concentrations of those metals (> 20 mg/l of platinum group metals) in the wastewater are the main challenges for biological removal of nitrogenous compounds from PMR wastewater. Nitrogenous compounds such as NH₄⁺-N and N0₃-N are strong metal ligands, which make it difficult to recover metals from the wastewater. Therefore, a bioprocess was developed for removal of nitrogenous compounds from carefully simulated PMR wastewater. A preliminary investigation of metal wastewater was carried out to determine its composition and physico-chemical properties, the ability to nitrify and denitrify under different pH conditions and denitrification with different carbon Source compounds and amounts. Even at pH 4, nitrification could be carried out. A suitable hydraulic retention time was found to be 72 hours. There was no significant difference between sodium acetate and sodium lactate as carbon sources for denitrification. Based on these results, a reactor comparison study was carried out using simulated PMR wastewater in three types of reactors: continuously stirred tank reactor (CSTR), packed-bed reactor (PBR) and airlift suspension reactor (ALSR). These reactors were fed with 30 mg/l of Rh bound in an NH₄⁺ based compound (Claus salt: pentaaminechlororhodium (III) dichloride). Total nitrogen removal efficiencies of > 68 % , > 79 % and > 45 % were obtained in the CSTR, PBR and ALSR, respectively. Serially connected CSTR-PBR and PBR-CSTR reactor configurations were then studied to determine the best configuration for maximum removal of nitrogenous compounds from the wastewater. The PBR-CSTR configuration gave consistent biomass retention and automatic pH control in the CSTR. Ammonium removal efficiencies > 95 % were achieved in both reactors. As poor nitrate removal was observed a toxicity study was carried out using respirometry and the half saturation inhibition coefficients for Pt, Pd, Rh and Ru were found to be 15.81, 25.00, 33.34 and 39.25 mg/l, respectively. A mathematical model was developed to describe the nitrogen removal in PMR wastewater using activated sludge model number 1 (ASMl), two step nitrification and metal toxicity. An operational protocol was developed based on the literature review, experimental work and simulation results. The optimum reactor configuration under the set conditions (20 mg/I of Rh and < 100 mg/I of NH₄⁺-N) was found to be PBR-CSTR-PBR process, which achieved overall NH₄⁺-N and N0₃⁻-N removal efficiencies of > 90 % and 95 %, respectively. Finally, a rudimentary microbial characterisation was carried out on subsamples from the CSTR and PBRsecondary. It was found that the CSTR biomass consisted of both rods and cocci while PBRsecondary consisted of rods only. Based on these experimental works, further research needs and recommendations were made for optimisation of the developed bioprocess for removal of nitrogenous compounds from PMR wastewater.
- Full Text:
- Date Issued: 2008
- Authors: Manipura, Walappuly Mudiyanselage Janakasiri Aruna Shantha Bandara
- Date: 2008
- Subjects: Factory and trade waste Centralized industrial waste treatment facilities Metals -- Absorption and adsorption Metals -- Environmental aspects Water -- Purification -- Mathematical models Water quality management Water reuse Metals -- Refining Microbiology -- Research
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4076 , http://hdl.handle.net/10962/d1007341
- Description: Removal of nitrogenous compounds from precious metal refinery (PMR) wastewater is important in terms of avoiding eutrophication (environmental protection), metal recovery (increased overall process efficiency and value recovery) and reuse of treated water (maximum use of natural resources). Extreme pH conditions (4 to 13 depending on the wastewater stream), high chemical oxygen demand (> 10,000 mg/I), numerous metals and high concentrations of those metals (> 20 mg/l of platinum group metals) in the wastewater are the main challenges for biological removal of nitrogenous compounds from PMR wastewater. Nitrogenous compounds such as NH₄⁺-N and N0₃-N are strong metal ligands, which make it difficult to recover metals from the wastewater. Therefore, a bioprocess was developed for removal of nitrogenous compounds from carefully simulated PMR wastewater. A preliminary investigation of metal wastewater was carried out to determine its composition and physico-chemical properties, the ability to nitrify and denitrify under different pH conditions and denitrification with different carbon Source compounds and amounts. Even at pH 4, nitrification could be carried out. A suitable hydraulic retention time was found to be 72 hours. There was no significant difference between sodium acetate and sodium lactate as carbon sources for denitrification. Based on these results, a reactor comparison study was carried out using simulated PMR wastewater in three types of reactors: continuously stirred tank reactor (CSTR), packed-bed reactor (PBR) and airlift suspension reactor (ALSR). These reactors were fed with 30 mg/l of Rh bound in an NH₄⁺ based compound (Claus salt: pentaaminechlororhodium (III) dichloride). Total nitrogen removal efficiencies of > 68 % , > 79 % and > 45 % were obtained in the CSTR, PBR and ALSR, respectively. Serially connected CSTR-PBR and PBR-CSTR reactor configurations were then studied to determine the best configuration for maximum removal of nitrogenous compounds from the wastewater. The PBR-CSTR configuration gave consistent biomass retention and automatic pH control in the CSTR. Ammonium removal efficiencies > 95 % were achieved in both reactors. As poor nitrate removal was observed a toxicity study was carried out using respirometry and the half saturation inhibition coefficients for Pt, Pd, Rh and Ru were found to be 15.81, 25.00, 33.34 and 39.25 mg/l, respectively. A mathematical model was developed to describe the nitrogen removal in PMR wastewater using activated sludge model number 1 (ASMl), two step nitrification and metal toxicity. An operational protocol was developed based on the literature review, experimental work and simulation results. The optimum reactor configuration under the set conditions (20 mg/I of Rh and < 100 mg/I of NH₄⁺-N) was found to be PBR-CSTR-PBR process, which achieved overall NH₄⁺-N and N0₃⁻-N removal efficiencies of > 90 % and 95 %, respectively. Finally, a rudimentary microbial characterisation was carried out on subsamples from the CSTR and PBRsecondary. It was found that the CSTR biomass consisted of both rods and cocci while PBRsecondary consisted of rods only. Based on these experimental works, further research needs and recommendations were made for optimisation of the developed bioprocess for removal of nitrogenous compounds from PMR wastewater.
- Full Text:
- Date Issued: 2008