Pharmaceutical analysis and aspects of the quality control of St. John's Wort products
- Authors: Wild, Tracy Joy
- Date: 2003
- Subjects: Hypericum perforatum , Hypericum perforatum -- Analysis , Hypericum perforatum -- Therapeutic use , Hypericum perforatum -- Physiological effect , Flavonoids -- Analysis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3804 , http://hdl.handle.net/10962/d1003282 , Hypericum perforatum , Hypericum perforatum -- Analysis , Hypericum perforatum -- Therapeutic use , Hypericum perforatum -- Physiological effect , Flavonoids -- Analysis
- Description: Most complementary medicines contain a multitude of chemical components, some of which are claimed to contribute to the biological activity of such products. Use of complementary medicines for preventative and therapeutic purposes is increasing rapidly worldwide. Unfortunately, although control of these products is essential to ensure quality, safety, and efficacy, the quality control of most herbal preparations is currently poor to non-existent, with little or no safety and efficacy data required to support the marketing and use of these products. The objective of this study was therefore to develop suitable analytical methods to qualitatively and quantitatively analyse the relevant components (rutin, isoquercitrin, hyperoside, quercitrin, quercetin, kaempferol, hypericin, pseudohypericin and hyperforin) in St John's Wort dosage forms for quality control purposes. A gradient HPLC method using a Luna 5·mC₁₈(2) 150 x 2.00mm internal diameter (i.d.) column and UV detection, was developed for the separation of six of the relevant flavonoid compounds in St John's Wort, namely rutin, isoquercitrin, hyperoside, quercitrin, quercetin and kaempferol. The development process involved a systematic investigation of gradient conditions, flow rate, and temperature. This method was subsequently applied to assay selected commercially available St John's Wort products. This system provided the necessary accuracy, precision and reproducibility and was associated with several advantages when compared to using standard bore (4.60 mm i.d.) HPLC columns. The method developed is currently the only known method that separates all six relevant flavonoids in a reasonable run time (less than 20 minutes). It is also one of the few methods that has sufficient separation between rutin, isoquercitrin and hyperoside. A qualitative method for the fingerprinting of flavonoid components was also developed, using capillary electrophoresis (CE). CE is a rapidly growing powerful analytical technique for the separation of charged compounds. Micellar electrokinetic chromatography (MEKC) is a very powerful electrophoretic technique that is capable of selectively resolving both neutral and ionic solutes in a single run. A MEKC method suitable for the separation and determination of various flavonoid constituents used as marker compounds in Hypericum perforatum was developed. Investigations into the effect of pH, ionic strength, applied voltage and capillary dimensions on separation were performed. The optimised method was then applied to qualitatively analyse various St John's Wort products on the market. This method was found to be advantageous in that it was simple, cost-effective, required minimal sample preparation and utilised very small quantities of sample. Due to the vast differences in chemical properties between the various marker and active components in St John's Wort, it was necessary to develop separate analytical methods for the flavonoids and for the other three relevant compounds (hypericin, pseudohypericin and hyperforin). An isocratic HPLC method using a Luna 5·mC₁₈(2) 150 x 2.00mm (i.d.) column and UV detection was developed for the separation of hypericin, pseudohypericin and hyperforin. The development process involved a systematic investigation of buffer molarity, mobile phase composition, pH, flow rate, and temperature. This method was subsequently applied to assay selected commercially available St John's Wort products on the South African market. This system also provided the necessary accuracy, precision and reproducibility, as well as the advantages associated with the use of a narrow bore column as opposed to the use of the more commonly used wider bore columns. This method was validated and used to quantitate these three compounds in various commercial St John's Wort products. By applying this method to liquid chromatography – tandem mass spectrometry (LC-MS-MS), qualitative analyses of the same products was performed to obtain confirmation of the quantitative HPLC results. Mass spectrometry is a powerful detection tool that is more selective and specific than many detection systems used with HPLC. Natural medicines usually constitute a multitude of constituents with much potential interference. In this regard LC-MS-MS is a powerful tool, with its ability to unequivocally identify target analytes regardless of the presence of interferences or complex matrices. ESI-MS-MS was used for the qualitative analysis of the content of the naphthodianthrones and hyperforin in the respective tablet products assayed with HPLC. LC-MS-MS analyses were performed in order to identify the constituents and to verify the specificity of the HPLC method. High inter-product and inter-batch variability was observed for all nine compounds assayed. These quantitative results were confirmed with the respective qualitative analyses. This study confirms the need for strict quality control of herbal medicinal products commercially available to consumers.
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Pharmaceutical Pictograms: Part 1: Communicating Medicine Information to the Low-literate Patient
- Authors: Dowse, Roslind , Ehlers, Martina S
- Date: 2003
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/157026 , vital:40080
- Description: To assess the influence of formal education on the interpretation of pharmaceutical pictograms.
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Pharmaceutical Pictograms: part 2: weird and wonderful interpretations
- Authors: Dowse, Roslind , Ehlers, Martina S
- Date: 2003
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/157037 , vital:40081
- Description: To assess the influence of formal education on the interpretation of pharmaceutical pictograms.
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Photochemical studies of binuclear phenoxysubstituted phthalocyanines containing catecholate bridges
- Authors: Seotsanyana-Mokhosi, Itumeleng , Maree, Suzanne , Maree, M David , Nyokong, Tebello
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/304808 , vital:58492 , xlink:href="https://doi.org/10.1142/S1088424603000239"
- Description: Binuclear ZnPc complexes covalently bridged by catechol units have been synthesized and their absorption and photochemical properties examined. The complexes studied are 1,2-bis-2',9',16',23'-triphenoxyphthalocyaninatozinc benzene (6a), 1,2-bis-2'-9',16',23'-tri-4-carboxyphe-noxyphthalocyaninatozinc benzene (6b), 1,2-bis-2',9',16',23'-tri-4-nitrophenoxyphthalocyaninato- zinc benzene (6c) and 1,2-bis-2'-9',16',23'-tri-4-tert-butylphenoxyphthalocyaninatozinc benzene (6d). Larger intramolecular coupling was observed for 6b and 6c, containing the carboxyphenoxy and nitrophenoxy substituents, respectively, than for 6a and 6d. A single Q band peak was observed for the fluorescence spectra of 6b and 6c, whereas, 6a and 6d showed a split Q band. The absence of the high energy fluorescence peaks corresponding to absorbance peaks in the 640 nm region, suggests that the intramolecular coupling is broken by excitation for complexes 6b and 6c.
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Phthalocyanines and related complexes as electrocatalysts for the detection of nitric oxide
- Authors: Nyokong, Tebello , Vilakazi, Sibulelo
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/290346 , vital:56741 , xlink:href="https://doi.org/10.1016/S0039-9140(03)00356-4"
- Description: Metallophthalocyanine (MPc) and metalloporphyrin complexes as well as some metalloproteins including myoglobin, hemoglobin, cyanocobalamin and cytochrome c catalyse the detection of nitric oxide (NO). The catalytic process often involve changes in the oxidation state of the catalyst. These complexes catalyse both the reduction and oxidation of NO. MPc complexes containing electroactive central metals such as CoPc and FePc generally show better catalytic activity towards the detection of NO than complexes containing electroinacive central metals. However, the involvement of ring based redox processes was confirmed for the homogenous NO catalysis using CoPc.
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Phylogenetics of advanced snakes (Caenophidia) based on four mitochondrial genes
- Authors: Kelly, Christopher M R , Barker, Nigel P , Villet, Martin H
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6960 , http://hdl.handle.net/10962/d1012005
- Description: Phylogenetic relationships among advanced snakes ( Acrochordus + Colubroidea = Caenophidia) and the position of the genus Acrochordus relative to colubroid taxa are contentious. These concerns were investigated by phylogenetic analysis of fragments from four mitochondrial genes representing 62 caenophidian genera and 5 noncaenophidian taxa. Four methods of phylogeny reconstruction were applied: matrix representation with parsimony (MRP) supertree consensus, maximum parsimony, maximum likelihood, and Bayesian analysis. Because of incomplete sampling, extensive missing data were inherent in this study. Analyses of individual genes retrieved roughly the same clades, but branching order varied greatly between gene trees, and nodal support was poor. Trees generated from combined data sets using maximum parsimony, maximum likelihood, and Bayesian analysis had medium to low nodal support but were largely congruent with each other and with MRP supertrees. Conclusions about caenophidian relationships were based on these combined analyses. The Xenoderminae, Viperidae, Pareatinae, Psammophiinae, Pseudoxyrophiinae, Homalopsinae, Natricinae, Xenodontinae, and Colubrinae (redefined) emerged as monophyletic, whereas Lamprophiinae, Atractaspididae, and Elapidae were not in one or more topologies. A clade comprising Acrochordus and Xenoderminae branched closest to the root, and when Acrochordus was assessed in relation to a colubroid subsample and all five noncaenophidians, it remained associated with the Colubroidea. Thus, Acrochordus + Xenoderminae appears to be the sister group to the Colubroidea, and Xenoderminae should be excluded from Colubroidea. Within Colubroidea, Viperidae was the most basal clade. Other relationships appearing in all final topologies were (1) a clade comprising Psammophiinae, Lamprophiinae, Atractaspididae, Pseudoxyrophiinae, and Elapidae, within which the latter four taxa formed a subclade, and (2) a clade comprising Colubrinae, Natricinae, and Xenodontinae, within which the latter two taxa formed a subclade. Pareatinae and Homalopsinae were the most unstable clades.
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Physiological, perceptual and performance responses during cricket activity
- Authors: King, Gregory Allen
- Date: 2003
- Subjects: Cricket , Sports -- Psychological aspects , Sports -- Physiological aspects
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5131 , http://hdl.handle.net/10962/d1005210 , Cricket , Sports -- Psychological aspects , Sports -- Physiological aspects
- Description: The present study sought to determine the influence of environmental conditions and protective clothing on physiological, perceptual and performance responses during batting activity. The investigation examined mean skin temperature, average heart rate, estimated sweat rate, rating of perceived exertion, thermal sensation rating, average sprint time and pre-post choice reaction time. Twenty-five cricketers (18-22 yr, 73.1 ± 9.6 kg, 1768 ± 75 mm, 12.6 ± 3.1% body fat, 1.89 ± 0.16 m2) performed a work-bout consisting of a seven-Over batting period, during which time they faced deliveries from a bowling machine and performed two shuttle runs every third ball to total four sprints per Over. Trials were carried out under High-stress (23.8 ± 2.2 °C) and Low-stress (13.3 ± 1.9 °C) environmental conditions (WBGT). Within each environmental condition subjects performed the test wearing full protective batting gear and no protective gear. Thus, four specific conditions were examined; high full-gear (HFG), high no-gear (HNG), low full-gear (LFG) and low no-gear (LNG). Two-way ANOVAs were calculated to determine whether there were differences between environmental conditions and whether differences existed between the clothing conditions. One-way ANOVAs were utilised to compute differences between the four specific conditions combining clothing and environment. High environmental stress and wearing protective clothing caused batsmen to experience significant physiological strain. The environment was the greatest stressor, with the protective gear exacerbating these effects. However, when padding covered skin areas directly, this was the primary skin temperature stressor, particularly later in the activity. For skin temperature and heart rate, the strain was the most pronounced at the end of the trials. Perceptual responses indicated that the protective gear had no influence on effort sense, thermal sensation or thermal comfort. However, environmental conditions had an effect, and High-stress conditions resulted in significantly higher perceptions of effort, elevated sensations of heat and greater thermal discomfort. Effort was perceived to be greatest towards the end of the trial. There were mixed findings for performance factors. In general sprint performance was not hindered by environmental stress, but protective clothing caused a reduction in several sprint times. Choice reaction times were for the most part unaffected by either environment or clothing and few differences were observed between pre and post times. It is contended that intense short duration batting activity, likely encountered during one-day participation, imposes a stress on batsmen. The stress is greater when conditions are warmer and protective padding is worn, although it is not sufficient to impede choice reaction time. However, protective gear did have a deleterious effect on sprint performance.
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Pipes, poles and people:
- Authors: Kyazze, Simwogerere
- Date: 2003
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159153 , vital:40273 , https://hdl.handle.net/10520/EJC146268
- Description: Tina James, a South African ICT consultant, tells the story of Minnie Barendse Kruger who had been struggling to get a Khoisan Cultural Village going in the Eastern Cape. Kruger set up a restaurant where traditional food is prepared, and the Barendse Griquas Trust stepped in and helped set up a multi-purpose Community Centre.
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Politics of asylum : sovereign considerations in the multilateral and humanitarian practices of refugee protection in post-apartheid South Africa
- Authors: Oduba, Victor
- Date: 2003
- Subjects: Refugees -- Africa , Refugees -- Government policy -- South Africa , Refugees -- Legal status, laws, etc. -- South Africa , Asylum, Right of -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2870 , http://hdl.handle.net/10962/d1007725 , Refugees -- Africa , Refugees -- Government policy -- South Africa , Refugees -- Legal status, laws, etc. -- South Africa , Asylum, Right of -- South Africa
- Description: Most scholars claim that international human rights norms embodied in formal international declarations and treaties have an important impact on domestic political interests and governmental practices. This reasoning about the impact of global human rights is often applied to the post-apartheid South African immigration and refugee policies. While I acknowledge that the ratification of United Nations Conventions on refugees has altered the traditional sovereignty considerations of South Africa towards asylum seekers, I take issue with the claims that South African refugee and asylum policies are primarily motivated and based on humanitarian considerations. Instead, I argue that these policies are based on sovereign considerations and strategic foreign policy interests. As a result this sovereign interests of South Africa to study has sought to demonstrate that largely explain decisions on the part accept or reject refugees. Although norms diffusion, international advocacy networks, and prestige factors have made a big impact, in practice the refugee policy has continued to reflect South Africa's strategic interests and domestic considerations at all levels. However, I have not argued that South Africa should overlook its national and foreign interests and abide by international human rights norms regardless of the cost of doing so. I have only sought to demonstrate that refugee protection is more when powerful national interests find it conducive to manage the destabilizing refugee flows.
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Pollination success in a deceptive orchid is enhanced by co-occurring rewarding magnet plants
- Authors: Johnson, Steven D , Peter, Craig I , Nilsson, L Anders , Agren, Jon
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6520 , http://hdl.handle.net/10962/d1005949 , http://www.jstor.org/stable/3449962
- Description: It has been debated whether pollination success in nonrewarding plants that flower in association with nectar-producing plants will be diminished by competition for pollinator visits or, alternatively, enhanced through increased local abundance of pollinators (the magnet species effect). We experimentally evaluated these effects using the nonrewarding bumblebee-pollinated orchid Anacamptis morio and associated nectar-producing plants at a site in Sweden. Pollination success (estimated as pollen receipt and pollen removal) in A. morio was significantly greater for individuals translocated to patches of nectar-producing plants (Geum rivale and Allium schoenoprasum) than for individuals placed outside (similar to20 m away) such patches. These results provide support for the existence of a facilitative magnet species effect in the interaction between certain nectar plants and A. morio. To determine the spatial scale of these interactions, we correlated the visitation rate to flowers of A. morio with the density of sympatric nectar plants in 1-m(2) and 100-m(2) plots centered around groups of translocated plants, and at the level of whole meadows (similar to0.5-2 ha). Visitation rate to flowers of A. morio was not correlated with the 1-m(2) patch density of G. rivale and A. schoenoprasum, but showed a significant positive relationship with density of these nectar plants in 100-m(2) plots. In addition, visitation to flowers of A. morio was strongly and positively related to the density of A. schoenoprasum at the level of the meadow. Choice experiments showed that bees foraging on the purple flowers of A. schoenoprasum (a particularly effective magnet species) visit the purple flowers of A. morio more readily (47.6% of choices) than bees foraging on the yellow flowers of Lotus corniculatus (17% of choices). Overall similarity in flower color and shape may increase the probability that a pollinator will temporarily shift from a nectar-producing "magnet" plant to a nonrewarding plant. We discuss the possibility of a mimicry continuum between those orchids that exploit instinctive food-seeking behavior of pollinators and those that show an adaptive resemblance to nectar-producing plants.
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Population biology of Octopus vulgaris on the temperate south-eastern coast of South Africa
- Authors: Oosthuizen, A , Smale, Malcolm J
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6768 , http://hdl.handle.net/10962/d1008045
- Description: Population structure and biology of Octopus vulgaris was investigated along the south-eastern coast of South Africa. Samples were collected inter- and sub-tidally as a precursor to the establishment of an experimental octopus fishery in the region. In total, 300 (intertidal) and 147 (subtidal) O. vulgaris were collected over a two year period. Females were found to dominate the intertidal area (sex ratio 2:1), while no difference was found subtidally (sex ratio 1:1). Of those collected intertidally, immature females were most prevalent while males ranged from immature to mature. Mature females were only found subtidally. A marked size difference was apparent, with the subtidal octopus being substantially larger. Although brooding females were found throughout the year, numbers peaked in summer. Individual fecundity ranged between 42,000–790,000 eggs. The total number of eggs produced and the number of eggs per egg string were correlated to female size. Diet did not vary greatly between the inter- and sub-tidal areas, with the main prey items being crustaceans, teleosts and octopus. It appears that the immature females use the intertidal area to feed and grow, before migrating to deeper areas to mature and spawn.
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Predictive modelling of species' potential geographical distributions
- Authors: Robertson, Mark Peter
- Date: 2003
- Subjects: Alien plants -- South Africa -- Geographical distribution Species -- Geographical distribution -- Mathematical models Cicadas -- South Africa -- Geographical distribution Scaevola plumieri -- South Africa -- Geographical distribution
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5816 , http://hdl.handle.net/10962/d1007189
- Description: Models that are used for predicting species' potential distributions are important tools that have found applications in a number of areas of applied ecology. The majority of these models can be classified as correlative, as they rely on strong, often indirect, links between species distribution records and environmental predictor variables to make predictions. Correlative models are an alternative to more complex mechanistic models that attempt to simulate the mechanisms considered to underlie the observed correlations with environmental attributes. This study explores the influence of the type and quality of the data used to calibrate correlative models. In terms of data type, the most popular techniques in use are group discrimination techniques, those that use both presence and absence locality data to make predictions. However, for many organisms absence data are either not available or are considered to be unreliable. As the available range of profile techniques (those using presence only data) appeared to be limited, new profile techniques were investigated and evaluated. A new profile modelling technique based on fuzzy classification (the Fuzzy Envelope Model) was developed and implemented. A second profile technique based on Principal Components Analysis was implemented and evaluated. Based on quantitative model evaluation tests, both of these techniques performed well and show considerable promise. In terms of data quality, the effects on model performance of false absence records, the number of locality records (sample size) and the proportion of localities representing species presence (prevalence) in samples were investigated for logistic regression distribution models. Sample size and prevalence both had a significant effect on model performance. False absence records had a significant influence on model performance, which was affected by sample size. A quantitative comparison of the performance of selected profile models and group discrimination modelling techniques suggests that different techniques may be more successful for predicting distributions for particular species or types of organism than others. The results also suggest that several different model design! sample size combinations are capable of making predictions that will on average not differ significantly in performance for a particular species. A further quantitative comparison among modelling techniques suggests that correlative techniques can perform as well as simple mechanistic techniques for predicting potential distributions.
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Press vs public enemy no 1:
- Authors: Berger, Guy
- Date: 2003
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159083 , vital:40266 , https://hdl.handle.net/10520/EJC146291
- Description: Our journalism about poverty is pitiful. It's a story about the poverty of our journalism. But let's start with the not-so-bad news: unlike many other countries, we do report poverty. Also, unlike many other places, we don't blame the victims - rather, we tend to be sympathetic.
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Press vs. public enemy no 1: challenges areas needing work
- Authors: Berger, Guy J E Gough
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/455048 , vital:75398 , https://hdl.handle.net/10520/EJC146291
- Description: Our journalism about poverty is pitiful. It's a story about the poverty of our journalism. But let's start with the not-so-bad news: unlike many other countries, we do report poverty. Also, unlike many other places, we don't blame the victims - rather, we tend to be sympathetic.
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Productivity and abundance of Sclerocarya birrea subsp. caffra in and around rural settlements and protected areas of the Bushbuckridge lowveld, South Africa
- Authors: Shackleton, Charlie M , Botha, Jenny , Emanuel, P L
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181607 , vital:43751 , xlink:href="https://doi.org/10.1080/14728028.2003.9752459"
- Description: Sclerocarya birrea (A. Rich.) Hochst, subsp. caffra (Sond.) Kokwaro is a common species throughout the semi-arid savannas of southern Africa, and is sought after by rural communities. It is frequently maintained in homesteads and fields in an agroforestry situation. It has also been identified by a number of international and national institutes as a key species for domestication and commercialisation. Yet, the sustainability of the resource and local user knowledge and practices have not been considered. This study reports on the abundance and productivity of S. birrea in four rural villages and neighbouring protected areas in the Bushbuckridge lowveld of the Limpopo Province, South Africa, where its common name is marula. The density of marula stems was measured in homestead plots, arable fields and the surrounding communal rangelands of each village. Fruit production was assessed by regular counting of fruit fall from marked trees of known size. Within the villages, fruit production was monitored via local community groups. Additional monitoring of fruiting was conducted on marked trees within local protected areas. The proportion of households planting or nurturing marula trees was determined through interviews with a stratified random sample of households. The density of marula trees was significantly higher in protected areas than the neighbouring communal lands, fields or homesteads. However, the majority of trees in protected areas were small, while those in homesteads were large and mature. Density of adult fruit-bearing female trees, was similar between the protected areas and homesteads, but less in fields and communal lands. S. birrea trees were maintained in 79 % of homesteads and 58 % of fields. Mean fruit yield per tree was significantly higher from village trees (less than 17 000 fruits) than protected area trees (more than 3 500 fruits), even after accounting for differences in tree size. The fresh mass of individual fruits was also greater on village trees than on trees in protected areas. Both these characteristics suggest some degree of historical selection of the trees in the homesteads and fields. There was a positive relationship between tree size and number of fruits produced.
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Progress towards the development and implementation of an unambiguous copper wire fingerprinting system
- Authors: Poole, Martin
- Date: 2003
- Subjects: Electroplating , Copper , Telecommunication , Theft -- Prevention
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5484 , http://hdl.handle.net/10962/d1005270 , Electroplating , Copper , Telecommunication , Theft -- Prevention
- Description: The Telecommunications industry in Southern Africa is faced with the problem of theft of the signal carrying copper wire, both from the ground and from telephone poles. In many cases, if the offenders are caught, the prosecuting party has no way of proving that the wire is the property of any one Telecommunication company, as any inked markings on the insulating sheaths have been burned off along with the insulation and protective coatings themselves. Through this work we * describe the problem, * specify the necessary and preferred technical properties of a viable solution, * report the preliminary investigations into the devising of an unambiguous "fingerprinting" of the 0.5 mm wires, including some of those solutions that, upon investigation, appear non-viable, * describe the development and implementation of an electrochemical marker with detection mechanism which has shown in proof-of-principle to work, * outline the road-map of necessary future work.
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Psycho-medical discourse in South African research on teenage pregnancy
- Authors: Macleod, Catriona I , Durrheim, Kevin
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6257 , http://hdl.handle.net/10962/d1007875
- Description: Catriona Macleod and Kevin Durrheim apply a Foucauldian analysis to the scientific literature on teenage pregnancy.
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Psychoanalysis and realism
- Authors: Rae, Andrew Kenneth McKenzie
- Date: 2003
- Subjects: Psychoanalysis Realism Human beings -- Psychology International relations -- Psychological aspects
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:2825 , http://hdl.handle.net/10962/d1003035
- Description: International politics has always been characterised by conflict. This has been true regardless of the political systems in place or of any specific time in the history of humanity. Inter-state conflict exists today despite the fact that the vast majority of the states of the world are members of the United Nations and signatories to various treaties aimed at removing conflict as a means of state action. The realist school of thought argues that the international system is characterised by continual state conflict, caused by competition over scarce resources. The propensity towards conflict is argued to be an essential characteristic of human nature and, as such, human nature is considered to be aggressive and conflictual. Thus, for the realist, inter-state competition, coupled with aggressive human nature, constitutes the primary cause of interstate conflict. This thesis aims to examine two criticisms of the realist position in depth. The first concerns the attribution of human nature to states. This logical progression is problematic because it creates a type of „state-nature‟ that cannot be defended without providing a logical link between the individual, the group and the state. It is therefore an aim of this thesis to provide this link, using methodological individualism, in order to provide a basis for the attribution of human nature to states. The second aim of this thesis is to examine the notion of human nature that is offered by the realists. It is not enough to claim that human nature is aggressive and conflictual merely because conflict has characterised international relations throughout history. Rather, one should examine the individual‟s psychological development, in order to gain an understanding of aggressive instincts apparent in human nature. The thesis therefore examines psychoanalysis in order to attempt an understanding both of human nature, and of the conditions under which human nature may manifest itself in an aggressive, conflictual manner. The intention of this thesis, then, is to provide a defence of political realism, highlighting the shortcomings of the two criticisms outlined above.
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Putting participatory communication into practice through community radio: a case study of how policies on programming and production are formulated and implemented at Radio Graaff-Reinet
- Authors: Kanyegirire, Andrew Steve Tumuhirwe
- Date: 2003
- Subjects: Radio broadcasting -- South Africa -- Graaff-Reinet , Radio in community development , Radio stations -- South Africa -- Graaff-Reinet -- Management
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3442 , http://hdl.handle.net/10962/d1002896 , Radio broadcasting -- South Africa -- Graaff-Reinet , Radio in community development , Radio stations -- South Africa -- Graaff-Reinet -- Management
- Description: In the South African (SA) model of community radio, listeners are expected to be in charge of the management and programming operations of stations. This study tests the SA model against the actual conditions at an existing station. For this purpose, the study focuses on Radio Graaff-Reinet, a community radio station in the Eastern Cape. Emphasis is on examining the extent to which members of the station’s target community are involved in its operations. The study first assesses the nature of this involvement, keeping in mind the principles of, ‘community ownership’ and ‘participatory programming’ on which the SA model of community radio is based. It is argued that the station does provide a valuable ‘public sphere’ for its listeners. The potential of this sphere remains limited, however, due to the impact of ongoing power struggles around the ownership of the station. The lack of proper systems for managing these struggles has contributed to the fact that the station continues to be in a constant state of flux, with a high turnover of staff and regular changes in its policies and strategies. The study argues that, until such systems are put in place, the principles of community ownership will not be fully realizable. Areas in which the struggle over ownership plays itself out can be identified in the relationship between the station’s Board of Directors and its managing staff, between one particular station manager and her staff and between the station and its target community. These struggles often take place in context of a debate about the financial sustainability of the station versus its developmental aims. It is argued that this opposition needs to be questioned since, until the station is financially stable, it will remain vulnerable to interference by powerful individuals and groups in its attempts to establish such developmental aims. The study then goes on to identify key weaknesses in the station’s approach to community ownership and participation. In particular, it is pointed out that various stakeholders in the station have contradictory understandings of what is meant by ‘community’, using the term to include or exclude sections of the Graaff-Reinet society in very different ways. There are also very different understandings at play about the concept of community radio itself. These contradictions have an impact on the station’s ability to implement participatory programming. This situation is exacerbated by the fact that the station does not have a consistent forum in which shared decision-making can take place. Consequently, the station also remains unable to draw effectively on its own volunteer staff and on its community as resources for programming content. Finally, the study explores the broader significance of the weaknesses that exist in the case of Graaff-Reinet, arguing that these are problems that repeat themselves throughout the South African community radio sector. Possible strategies for addressing these problems are suggested, including approaches to monitoring and research, training, organizational development and advocacy.
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Pyrroloiminoquinone metabolites from South African Latrunculid sponges
- Authors: Antunes, Edith Martins
- Date: 2003
- Subjects: Sponges -- South Africa PQQ (Biochemistry) Marine metabolites -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4340 , http://hdl.handle.net/10962/d1005001
- Description: An in depth chemical investigation of the major and minor pyrroloiminoquinone metabolites produced by four species of endemic South African Latrunculid sponges, collected from Algoa Bay and the Tsitsikamma Marine Reserve off the south eastern coast of South Africa, yielded eleven new and twelve known pyrroloiminoquinone metabolites. The structures of the new metabolites were determined using standard spectroscopic techniques. Tsitsikamma pedunculata was shown to contain 7,8-dehydro-3-dihydro-discorhabdin C (2.1), 14-bromo-7,8-dehydro-3-dihydro-discorhabdin C (2.2), discorhabdin S (2.3), 14-bromo-1-hydroxy-discorhabdin S (2.4), 1-bromo-2-hydroxy-4-debromo-discorhabdin S (2.5), and 2,4-debromo-3-dihydro-discorhabdin C (2.6), together with the known compounds 14-bromo-discorhabdin C (1.51), 14-bromo-3-dihydro-discorhabdin C (1.52) and 3-dihydro-discorhabdin C. The metabolites from T. pedunculata were characterised by the presence of a reduced C-3 carbonyl and bromination at C-14. Compounds isolated from a second Latrunculid sponge, Latrunculia lorii, ranged from a substituted bicyclic pyrrolecarboxylic acid, makaluvic acid A (1.47), to the simple tricyclic known pyrroloiminoquinones makaluvamine C (1.33) and damirone B (1.20) and the more complex discorhabdin D type metabolites, discorhabdin M (3.2), 1-amino discorhabdin D (3.3), 1-methoxy discorhabdin D (3.4) and 1-alanyl discorhabdin D (3.5). Discorhabdin G* (3.1) was also isolated and characterised. This is the first reported occurrence of the known compounds 1.20, 1.33 and 1.47 in a Latrunculia sponge. Discorhabdin and bis-pyrroloiminoquinone type compounds predominated in Tsitsikamma favus. Three known, tsitsikammamines A (1.71) and B (1.72), 1.52, and five new pyrroloiminoquinones, tsitsikammamine N-oxime (4.1), tsitsikammamine B N-oxime (4.2), 2.1, 2.4 and 2.6, were isolated from this sponge. A fourth Latrunculid sponge (Strongylodesma sp.) yielded three known compounds, discorhabdins A (1.57), D (1.61) and 1.53, and one new pyrroloiminoquinone 3.3. The dual role of these metabolites as cytotoxic agents and pigments resulted in an attempt to relate the photochemical properties of these metabolites to their cytotoxicity. The pyrroloiminoquinone metabolites studied exhibited moderate singlet oxygen quantum yields, while three compounds (1.57, 4.1 and 4.2) were shown to be capable of producing radicals at a wavelength of 532 nm. The possibility of a correlation between the electrochemical properties and anti-cancer (HCT-116) activity of selected pyrroloiminoquinones was explored. A study of the oesophageal and ovarian cytotoxicities of two pyrroloiminoquinones (1.57 and 1.72), together with an investigation into the intercalation and topoisomerase I inhibitory activity of the bis-pyrroloiminoquinones (1.71, 1.72, 4.1 and 4.2), are presented.
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