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Photophysical and photochemical studies of sulfur containing phthalocyanine derivatives in the presence of folic acid

  • Authors: Nombona, Nolwazi , Nyokong, Tebello
  • Date: 2012
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/243180 , vital:51124 , xlink:href="https://doi.org/10.1016/j.ica.2012.03.051"
  • Description: The syntheses of zinc and magnesium 9,16,23-tris-(5-trifluoromethyl-2-mercaptopyridine)-2-(carboxy)phthalocyaninato complexes are described for the first time. The photophysical and photochemical parameters of these molecules in the absence or presence of folic acid are compared to the corresponding oxygen bridged complexes and to 2,9,17,23-tetrakis-[(1,6-hexanedithiol)phthalocyaninato]zinc(II), [8,15,22-tris-(naptho)-2-(amidoethanethiol)phthalocyaninato]zinc(II) and zinc phthalocyanine tetrasulfonate. In the absence of folic acid, the complexes show relatively good triplet quantum yields (ranging from 0.52 to 0.88) in DMSO with reasonable triplet lifetime between 140 and 470 μs. The complexes showed high singlet oxygen quantum yield values ranging from 0.27 to 0.66 in the absence of folic acid. In the presence of folic acid, the triplet quantum yield values were between 0.37 and 0.75 and the lifetimes were significantly reduced (70–320 μs).
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  • Date Issued: 2012

Photophysicochemical and photodynamic studies of phthalocyanines conjugated to selected drug delivery agents

  • Authors: Nombona, Nolwazi
  • Date: 2012
  • Subjects: Phthalocyanines Photochemistry Photochemotherapy Drug delivery systems Magnesium Zinc Nanoparticles Staphylococcus aureus
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:4333 , http://hdl.handle.net/10962/d1004994
  • Description: This work reports on the successful synthesis, characterisation and photophysical properties of new asymmetric metal free, magnesium and zinc phthalocyanines. The synthesis of symmetrical phthalocyanines is also reported. A selection of phthalocyanines have been conjugated, covalently linked, encapsulated or mixed with selected of drug delivery agents which include gold or silver nanoparticles, poly-L-lysine, liposomes and folic acid. The influence of delivery agent on the photophysical and photochemical properties of conjugated phthalocyanine is investigated. The studies showed that the Au nanoparticle significantly lowered the fluorescence quantum yield values of the phthalocyanines. The photodynamic activity of Zn phthalocyanine-ε-polylysine conjugates in the presence of nanoparticles towards the inactivation of Staphylococcus aureus showed high photoinactivation in the presence of silver nanoparticles. The presence of silver nanoparticels from the minimal inhibition concentration (MIC₅₀) studies showed remarkable growth inhibition for the tested conjugates even at low concentrations. The conjugate also showed no dark toxicity when evaluated using the chick choriallantoic membrane (CAM) assay. The efficiency of selected zinc phthalocyanine as photodynamic therapy (PDT) agents was investigated. The production of reactive oxygen species (ROS) and phototoxicity of the photosensitizers were assessed. Healthy fibroblast cells and breast cancer (MCF-7) cells were treated with either free phthalocyanine or phthalocyanine bound to either gold nanoparticles or encapsulated in liposomes. Cell viability studies showed the optimum phototoxic effect on non-malignant cells to be 4.5 J.cm⁻². The PDT effect of the liposome bound phthalocyanine showed extensive damage of the breast cancer cells. Gold nanoparticles only showed a modest improvement in PDT activity.
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  • Date Issued: 2012

Photophysicochemical studies of phenylthio phthalocyanines interaction with gold nanoparticles and applications in dye sensitised solar cells and optical limiting

  • Authors: Forteath, Shaun
  • Date: 2012
  • Subjects: Phthalocyanines , Nanoparticles , Photochemistry
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4334 , http://hdl.handle.net/10962/d1004995 , Phthalocyanines , Nanoparticles , Photochemistry
  • Description: The syntheses, spectroscopic characterisation, photophysical and photochemical studies have been conducted for a variety of phenylthio substituted phthalocyanines (Pcs). Comparisons have been made taking into consideration the influence of the central metal ion, solvent properties and substituent type. The optical limiting properties were also determined for all the Pcs synthesised. A low-symmetry metallophthalocyanine complex was similarly characterised and the photoelectrochemical parameters determined when used as a sensitiser of nanoporous ZnO. The symmetric analogue was conjugated to gold nanoparticles to determine the influence of interactions on its photophysical properties and distinct differences occurred in the absorption and fluorescence spectra suggesting successful formation of conjugates.
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  • Date Issued: 2012

Photophysics and photochemistry of octaglucosylated zinc phthalocyanine derivatives

  • Authors: Iqbal, Zafar , Ogunsipe, Abimbola , Nyokong, Tebello , Lyubimtsev, Alexey , Hanack, Michael , Ziegler, Thomas
  • Date: 2012
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/244416 , vital:51255 , xlink:href="https://doi.org/10.1142/S1088424612500630"
  • Description: The ground state electronic absorption spectra, photophysics and photochemistry of amphiphilic octaglucosylated zinc phthalocyanines containing oxygen or sulfur bridges are presented. Triplet quantum yield values for the two dyes (in DMF and DMSO) vary between 0.71 and 0.84, while singlet quantum yield values lie between 0.63 and 0.75. Fluorescence lifetimes were determined experimentally by time correlated single photon counting and semi-empirically by fluorescence quenching techniques; and values from both methods were within the same range. Kinetic data were obtained for the quenching of the triplet state of the phthalocyanines by ground state molecular oxygen; the bimolecular collisional quenching rate constant range between 2.35 × 108 and 1.13 × 109 M-1.s-1. These values suggest that triplet states of the dyes are effectively quenched by ground molecular oxygen.
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  • Date Issued: 2012

Physico-chemical and microalgal characteristics of the Goukamma Estuary

  • Authors: Kaselowski, Tanja
  • Date: 2012
  • Subjects: Estuarine ecology , Estuaries -- South Africa
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:10623 , http://hdl.handle.net/10948/d1011130 , Estuarine ecology , Estuaries -- South Africa
  • Description: Estuaries are intrinsically complex and dynamic ecosystems that display marked spatial and temporal variability. Because estuaries are situated at the receiving end of catchment activities, they are at particular risk of alterations to their natural complexity. The overarching objective of this study was to gain an overview of the abiotic conditions and biotic response of the Goukamma Estuary, a small temporarily open/closed estuary (TOCE) which is situated in a relatively undisturbed catchment in the Southern Cape. Physico-chemical properties drive estuarine ecology, and together with biological indicators, are commonly assessed to determine the present status of an estuary. During the study, physico-chemical parameters reflected great spatial and temporal variability in response to the mouth state over a 13 month period. Parameters ranged within expected limits, as proposed by the conceptual model for water quality of TOCE’s (Snow and Taljaard 2007). Of particular importance was the prominent occurrence of salinity stratification and hypoxic conditions (dissolved oxygen [DO] < 3 mg l-1) during both open and closed mouth states. Data indicated that in the wide and shallow lower reaches, weak stratification gradients were present and oxygenated conditions (DO > 6 mg l-1) were maintained throughout the water column mainly by wind and tidal action. However, stratification increased towards the deeper, channel-like middle and upper reaches of the estuary, followed by a significant reduction in bottom DO concentrations and development of hypoxia and anoxia. Bottom water hypoxia commonly occurs in microtidal estuaries due to the limited influence of mixing forces, mainly by wind and tidal action. The Goukamma Estuary is a channel-like microtidal estuary where stratification effectively limited oxygenation of the bottom water which resulted in frequent occurrence of bottom water hypoxia. During June 2010 when the highest local rainfall (75 mm) was recorded for the region, salinity and DO data showed that this amount of rainfall was insignificant as it did not replenish the water column of oxygen. Only the surface 0.5 m layer was fresh and oxygenated while below this, the water column was completely hypoxic. In an unimpacted state, the Goukamma Estuary is a blackwater system and is expected to be nutrient poor; however, farming activities in the catchment have resulted in elevated nutrient concentrations. This study showed that significantly higher nutrient concentrations were measured in the middle and upper reaches of the estuary, adjacent to cattle farms situated in the floodplain of these reaches. Nutrient concentrations represented mesotrophic (dissolved inorganic nitrogen [DIN] > 500 μg l-1) to eutrophic conditions (dissolved inorganic phosphorus [DIP] > 25 μg l-1). Nutrient input stimulated phytoplankton to attain a significantly high biomass, ranging between 0.3 – 112 μg l-1 (~ 7.7 ± 1.3 μg l-1; n = 128) and 0.8 – 289 μg l-1 (~ 21.1 ± 4.4 μg l-1; n = 80) during the open and closed states, respectively. High organic loads are associated with high oxygen demands which consequently result in hypoxia following decomposition. Exacerbated by natural salinity stratification which effectively limits oxygenation of the water column, unnaturally high nutrient concentrations and coinciding organic loads place the estuary at particular risk of degradation. This study captured key patterns and processes by quantifying salinity, oxygen and nutrient concentrations in addition to biological indicators (phytoplankton biomass and community composition). Considering possible budget constraints, it is recommended that monthly salinity and oxygen concentrations should be monitored as well as seasonal nutrient concentrations. It is also recommended that riparian buffer zones should be established in the middle and upper reaches of the estuary, as these vegetation buffers have been well documented to contribute to nutrient attenuation and improved water quality from agricultural run-off.
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  • Date Issued: 2012

Physico-chemical properties of lutetium phthalocyanine complexes in solution and in solid polystyrene polymer fibers and their application in photoconversion of 4-nitrophenol

  • Authors: Zugle, Ruphino , Nyokong, Tebello
  • Date: 2012
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/243520 , vital:51160 , xlink:href="https://doi.org/10.1016/j.molcata.2012.02.010"
  • Description: The photophysical and photochemical behavior of two phthalocyanine complexes of lutetium peripherally substituted with tetraphenoxy and tetra-2-pyridiloxy groups were studied in solution and when dispersed in polystyrene polymer fiber. The phthalocyanines were found not to fluoresce significantly in solution and not at all within the fiber matrix as compared with standard unsubstituted zinc phthalocyanine. They showed very promising photoactivity in solution with high singlet oxygen quantum yields. Their photoactivity within the polymer fiber matrix was also demonstrated with the photoconversion of 4-nitrophenol, a water pollutant. The photodegradation process with both phthalocyanines follows first order kinetics similar to that observed for the zinc phthalocyanine and the photo-products were found to be hydroquinone, benzoquinone and 4-nitrocatechol.
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  • Date Issued: 2012

Phytochemical analysis and bioactivity of Garcinia Kola (Heckel) seeds on selected bacterial pathogens

  • Authors: Seanego, Christinah Tshephisho
  • Date: 2012
  • Subjects: Drug resistance in microorganisms , Garcinia , Antibiotics , Medicinal plants , Microbial sensitivity tests , Streptococcal infections , Streptococcus , Staphylococcus aureus infections , Salmonella typhimurium , Traditional medicine
  • Language: English
  • Type: Thesis , Masters , MSc (Microbiology)
  • Identifier: vital:11259 , http://hdl.handle.net/10353/420 , Drug resistance in microorganisms , Garcinia , Antibiotics , Medicinal plants , Microbial sensitivity tests , Streptococcal infections , Streptococcus , Staphylococcus aureus infections , Salmonella typhimurium , Traditional medicine
  • Description: Garcinia kola is one of the plants used in folklore remedies for the treatment of microbial infections. Bacterial resistance to commonly used antibiotics has necessitated the search for newer and alternative compounds for the treatment of drug resistant microbial infections. This study focuses on the bioactivity of G. kola seeds on Streptococcus pyogenes (ATCC 49399), Staphylococcus aureus (NCTC 6571), Plesiomonas Shigelloides (ATCC 51903) and Salmonella typhimurium (ATCC 13311), organisms which can cause illnesses from mild to severe with potentially fatal outcomes. The crude ethyl acetate, ethanol, methanol, acetone and aqueous extracts were screened by agar-well diffusion method and the activities of the extract were further determined by Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) assays. The inhibition zones ranged from 0 - 24 mm, while MIC and MBC of the extract ranged between 0.04 - 1.25 mg/mL and 0.081 - 2.5 mg/mL respectively. Chloroform/ Ethyl Acetate/ Formic acid (CEF) solvent system separated more active compounds followed by Ethyl Acetate/ Methanol/ Water (EMW) and Benzene/ Ethanol/ Ammonium Hydroxide (BEA). The extracts were fractionated by Thin Layer Chromatography (TLC). Bioautography was used to assess the activity of the possible classes of compounds present in the more active extracts. Column chromatography was used to purify the active compounds from the mixture while Gas Chromatography-Mass Spectrometry (GC-MS) was used to identify the phyto components of the fractions. The MIC of the fractions ranged between 0.0006 - 2.5 mg/mL. CEF 3 (F3), CEF 11 (F11) and CEF 12 (F12) revealed the presence of high levels fatty acids Linoleic acid, 1, 2-Benzenedicarboxylic acid and 2, 3-Dihydro-3, 5-dihydroxy-6-methyl, respectively. The results obtained from this study justify the use of this plant in traditional medicine and provide leads which could be further exploited for the development of new and potent antimicrobials.
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  • Date Issued: 2012

Phytoplankton associated with mesoscale eddies in the Mozambique Channel

  • Authors: O'Reilly, Bevan James
  • Date: 2012
  • Subjects: Mozambique Channel. , Phytoplankton
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:10622 , http://hdl.handle.net/10948/d1010967 , Mozambique Channel. , Phytoplankton
  • Description: The study undertaken was an attempt to provide information on the effect that oceanographic features common in the Mozambique Channel have on primary production. Oligotrophic conditions dominated the Mozambique Channel at the time of sampling and the introduction of nutrients into the euphotic zone by upwelling processes were identified as cyclonic eddies. Differences in physico-chemical variables between surface and F-max across all sites proved to be stronger than the physico-chemical variables between 4 grouped oceanographic features. This was revealed by stronger variations in phytoplankton community structure and chlorophyll a concentration between surface and F-max compared to oceanographic features sampled. One of the hypotheses presented for the study was that diatoms would dominate phytoplankton communities within a cyclonic eddy. This was not the case as the coccolithophorid, Emiliania huxleyi Lohmann (Hay and Mohler 1967) dominated F-max and surface water in the cyclonic eddies and most other sites. Phytoplankton community structure did not differ significantly between the oceanographic features sampled which contradicted another one of hypotheses presented in the study. Chlorophyll a concentration in surface water of the cyclonic eddies was significantly higher than in surface waters within the anti-cyclonic eddy. F-max was not significantly different in phytoplankton biomass between these two system types. The cyclonic eddies and anti-cyclone had similar phytoplankton diversity which did not verify the hypothesis that there would be less phytoplankton species diversity within cyclonic eddies compared to the anti-cyclonic eddy. Phytoplankton community structure differed between F-max (depth at which maximum chlorophyll a is found) and the surface. This phytoplankton community difference was linked to differences in physico-chemical variables between the two depths. The diatoms Thalassionema nitzschioides, Pseudo-nitzschia sp.A, Pseudo-nitzschia sp.B, Thalassiosira sp.C, Thalassiosira sp.E, Bacteriastrum furcatum, Guinardia cylindrus, Nitzschia closterium, Hemiaulus hauckii, and Nitzschia braarudii revealed the only discernible ecological similarity amongst phytoplankton species across all sites and depths. This is important as it revealed that these species were regularly found occupying similar depths and potentially similar physico-chemical ranges in the water column which suggest these diatom species responded to a dominant source of variation. Distribution patterns of species and of ecologically defined groups support the hypothesis that diatom species and assemblages are good indicators of the changing character of an upwelling system. These statements lead to the assumption that the diatom grouping found in this study indicates areas of upwelling where water temperatures are reduced and nutrients are more readily available. One must keep in mind that ordination techniques are only descriptive and no significance is tested. The coccolithophorid D. anthos and the dinoflagellate Phalacroma spp. were noted as being most dissimilar to all other phytoplankton species with regards to their position in the water column and their response to physico-chemical variables. Finally, the dominance of E. huxleyi in the Mozambique Channel during November/December of 2009 reveals the potential vulnerability of phytoplankton in the channel to ocean acidification.
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  • Date Issued: 2012

Plantar pressure and impulse profiles of students from a South African university

  • Authors: Kramer, Mark
  • Date: 2012
  • Subjects: Human mechanics , Foot -- Movements , Joints -- ange of motion , eng
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:10095 , http://hdl.handle.net/10948/d1010606 , Human mechanics , Foot -- Movements , Joints -- ange of motion
  • Description: Most activities of daily living and numerous modes of physical activity incorporate some form of ambulation, of which the foot and ankle constitute the first link in the kinetic chain. A change in foot or ankle structure may therefore have subsequent effects on the superincumbent joints of the human body such as the knee, hip and lower back. Plantar pressure and impulse measurements can therefore provide greater insight into the mechanics of the foot under load-bearing conditions with regards to the areas and regions of the foot that exhibit the largest pressure values and impulse figures. Hence, it is of importance to establish normative data so as to obtain a frame of reference to identify those individuals that fall outside these norms and may exhibit a larger probability of injury. Aim and Objectives: The primary aim was to identify and compare the plantar pressure distribution patterns and impulse values of students of a South African university of different gender and race groups. To realise this aim two specific objectives were set. The first was to determine whether height, weight, body mass index (BMI), gender, race, and the level of physical activity were related to the pressure and impulse values obtained, and the second was to generate reference tables from the normative data gathered. Method: The RS Footscan system was used to measure the pressure and impulse values of the foot. The characteristics that were analysed were height, weight, body mass index and the level of physical activity of the participant and their respective association with plantar pressure and impulse values obtained. This information was then used to establish normative data. A quasi-experimental study design utilising convenience sampling was implemented as the intention was to investigate as single instance in as natural a manner as possible. Convenience sampling was used with predefined inclusion and exclusion criteria. A total of 180 participants were utilised in this study and were subdivided as follows: Gender: Males (n = 90); Females (n = 90); Race: African black (n = 60); white (n = 60) and coloured (n = 60). Each race group therefore comprised of 30 males and 30 females respectively. The anthropometric profile of participants was as follows: Age (S.D.) = 22.21 (S.D. ± 2.93) years; Height (S.D.) = 169.69 (S.D. ± 8.91) cm; Weight (S.D.) = 66.97 (S.D. ± 12.01) kg; BMI (S.D.) = 23.16 (S.D. ± 3.15) kg/m2. Participants were asked to complete a questionnaire prior to testing that would identify all exclusion criteria consisting of: the presence of foot pain or deformity, acute lower extremity trauma, lower extremity surgery, exhibited problems of performance including eye, ear or cognitive impairment, diabetes mellitus or other neurological neuropathy, or the use of walking aids. Anthropometric measurements were then taken for those participants that qualified for the study. Participants were required to perform approximately five warm-up trials to familiarise themselves with the testing equipment before testing commenced. A total of ten successful trails were subsequently recorded for each participant, with three footprints being recorded per trial on the pressure platform, thereby comprising 30 footprints (15 left foot and 15 right foot) per participant that were analysed regarding pressure and impulse values. The two-step gait initiation protocol was implemented which was proven to be a valid and reliable means of assessing gait. Participants were instructed to walk at a comfortable walking speed between 1.19 – 1.60 m/s to ensure conformity between all participants as between-trial gait velocities were proven to be significantly variable. The foot was subdivided into ten anatomical areas focusing on the great toe, lesser toes, metatarsal 1, metatarsal 2, metatarsal 3, metatarsal 4, metatarsal 5, midfoot, medial heel and lateral heel. These ten areas were then grouped into one of three regions, namely the forefoot region (great toe, lesser toes, and all five metatarsal head areas), midfoot region (midfoot area), and rearfoot/heel region (medial and lateral heel areas). Once all relevant data was gathered, corrected and analysed it was used to establish normative data tables pertaining to the various gender and race groups. Results: Of the ten individual pressure and impulse areas, the second and third metatarsal heads demonstrated the highest mean peak pressure and impulse values. Once grouped into one of the three regions, the heel region was ascribed with the largest impulse and pressure values. It was established that statistically and practically significant racial pressure differences were apparent in the left and right forefoot and midfoot regions, with black and coloured individuals yielding the highest values, whereas white participants yielded the lowest. The same was true with regards to impulse figures in that both statistical and practical significant levels were established in the forefoot and midfoot regions. Black and coloured participants exhibited larger impulse values than the white participants. The level of physical activity was found to be associated with both pressure and impulse values over the various regions of the foot. Black individuals that were largely inactive as well as moderately active coloured participants yielded the highest pressure and impulse values, which were found to be statistically and practically significant over the forefoot regions. Conversely, white participants of all physical activity levels as well as coloured participants of both low and high physical activity levels exhibited the lowest pressure values over the forefoot region, which were also found to be statistically and practically significant. The anthropometric variables of height, weight and BMI were found to relate statistically to pressure and impulse values under the various regions of the foot, but none were found to be of any practical significance (r < .30). Conclusion: It was clearly established that both gender and race specific differences existed regarding plantar pressure and impulse values of the normal foot. Plantar pressure and impulse values were also associated with the level of physical activity of the individual, thereby indicating that the level of physical activity could be a contributing factor to altered pressure and impulse values. Anthropometric variables such as height, weight and BMI could not solely account for the variances observed in pressure and impulse. Further research is required to determine whether pressure or impulse values above or below those obtained predispose an individual to injury and to contrast between various activity or sporting codes and the effect of these on plantar pressure and impulse figures. Finally, from the collected data one was able to establish reference tables for the specific gender and race groups for both plantar pressure and impulse values. This enables one to classify individuals based on the pressure and impulse values generated.
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  • Date Issued: 2012

Political agency in South African shack settlements

  • Authors: Pithouse, Richard, 1970-
  • Date: 2012
  • Language: English
  • Type: Conference paper
  • Identifier: vital:6194 , http://hdl.handle.net/10962/d1008580
  • Description: (From the introduction) In 2004 Mike Davis asked whether or not what he called 'the informal proletariat' could attain historical agency. The question posed by Davis sparked a largely speculative discussion in the radical edge of the metropolitan academy that often paid scant regard to the many careful studies dealing with the political agency of shack dwellers. The debate about the political capacities of the urban poor stretches back to Karl Marx and Friedrich Engels, whose views on the matter are well known, and Mikhail Bakunin who sustained their objectification but inverted its logic to conclude that “in them and only in them [the lumpen-proletariat ], and not in the bourgeois strata of workers, are there crystallized the entire intelligence and power of the coming Social Revolution”. In Africa the rational discussion of this question begins with Frantz Fanon who,dying of leukaemia and dictating his words from a mattress on the floor of a flat in Tunis in 1961, insisted that “Marxist analysis should always be slightly stretched every time we have to do with the colonial problem.” One of the many ways in which he stretched the Marxism in the air at the time was to take the view that the lumpen-proletariat, as a sociological category, had no fixed political meaning. People who had been 'circling the cities' hoping, he said, 'to be let in', had sometimes offered their services to colonial oppression and had sometimes joined the revolution against colonialism. Moreover he argued that in the colonial context the urban poor, living outside of the “world of compartments”, did not only become a “gangrene eating into the heart of colonial domination” as an unintended consequence of a desire to survive, of a “biological decision to invade the enemy citadels”, but that some amongst these people would assume explicit political agency and that it is: “in the people of the shanty towns and in the lumpen-proletariat that the insurrection will find its urban spearhead.” In reaching this conclusion, and in insisting on this particular stretching of the dominant currents of the Marxism of the time, Fanon was sustaining a fidelity both to the actually existing politics that he had witnessed in various African countries as well as to his founding ethical axiom - to recognise “the open door of every consciousness.”
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  • Date Issued: 2012

Political parties in South African law

  • Authors: Tiry, Zaahira
  • Date: 2012
  • Subjects: Political parties -- Law and legislation -- South Africa , Politics -- Law and legislation -- South Africa
  • Language: English
  • Type: Thesis , Masters , LLM
  • Identifier: vital:10285 , http://hdl.handle.net/10948/d1012414 , Political parties -- Law and legislation -- South Africa , Politics -- Law and legislation -- South Africa
  • Description: This dissertation is a literature study of the legal regime of political parties in post-apartheid South Africa. A constitutional perspective is adopted throughout the study in order to confine the topic to the realm of South African law. Hence, the focus of the study is to identify legal rights contained in chapter two of the Constitution and to also identify other provisions of the Constitution that have a bearing on political parties. As mentioned in the conclusion, section 19 of the Constitution, set the scene for the development of this study. An analysis of the constitutional provisions highlighted in this study, case law and present legislation dealing with political parties reveals that there is a need for comparative research and the adoption of adequate legislation to regulate the functioning of political parties in South Africa. It is submitted that the regulation of parties by statute is required to ensure a just political order whereby the functioning of political parties is in line with the Constitution.
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  • Date Issued: 2012

Population dynamics of the white shark, Carcharodon carcharias, at Mossel Bay, South Africa

  • Authors: Ryklief, Rabiah
  • Date: 2012
  • Subjects: White shark -- South Africa -- Mossel Bay , Sharks -- South Africa -- Mossel Bay
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:10717 , http://hdl.handle.net/10948/d1012077 , White shark -- South Africa -- Mossel Bay , Sharks -- South Africa -- Mossel Bay
  • Description: Mossel Bay is internationally recognised as one of the centres of abundance of white sharks in South Africa. During 2008 – 2010 there were four sites within the bay i.e. Seal Island, Hartenbos, Kleinbrak and Grootbrak, which were sampled to gain insight into the population dynamics of this species. Currently, life history information on white sharks in this area is limited. This study used a combination of mark-recapture using photographic identification techniques and sight per unit effort methods. Inter-annual, seasonal and spatial patterns in abundance are assessed. The effects of environmental parameters on abundance are also investigated. Photographic identification techniques were employed to identify unique individuals within the sampled population. This modified mark-recapture approach is therefore non-invasive and cost-effective. Open population POPAN parameterization was used to analyse the data in software program MARK. The total population was estimated at 389 sharks (351 – 428; 95 percent CI). Over the three year period, a marginal (yet non-significant) decline in numbers was observed, in terms of both monthly and seasonal population estimates. Sightings per unit effort data were collected during sampling trips. The relative abundance and body size composition of white sharks demonstrated significant spatial and seasonal variation. The highest and lowest relative abundance was observed at Seal Island and Hartenbos, respectively, and is likely attributed to prey availability. Although white sharks were present year-round in Mossel Bay, the highest relative abundance occurred during summer and the lowest relative abundance occurred during spring. White sharks were grouped into three main size classes based on estimated total length (TL): Young of the year (YOY) (125 – 174cm), juvenile (175 – 324cm) and adult (325 – 524cm). YOY white sharks were most prevalent at Grootbrak, with juvenile and adult individuals concentrating at Seal Island. Although most size classes were present throughout the year, seasonal differences were observed. YOY individuals were most abundant in the autumn months, juvenile size-classes appeared to concentrate in the study area during winter, and the adult individuals were most abundant in the spring months. Overall, there was a high concentration of white sharks ranging in size between 175 – 324cm TL, and it was thus hypothesised that Mossel Bay represents an interim nursery or grow out area for white sharks in South Africa. Data collected from 2008 and 2009 was used to investigate the relationship between specific environmental parameters, i.e. sea surface temperature and vertical water clarity, in relation to the relative abundance of white sharks. Sea surface temperature and vertical water clarity observed in this study ranged from 9.3 - 22.7°C and 0 – 10m, respectively. Sea surface temperature did not have a significant influence on the relative abundance of white sharks and this may be attributed to the thermoregulatory capacity of the species. Vertical water clarity, however, did significantly influence the relative abundance. Furthermore, the combined effect of site and season significantly influenced the relative abundance of white sharks and is probably linked to the distribution and abundance of inshore prey resources.
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  • Date Issued: 2012

Population dynamics of the Zuurberg Cycad and the predicted impact of climate change

  • Authors: Singh, Karishma
  • Date: 2012
  • Subjects: Cycads -- South Africa -- Eastern Cape , Encephalartos -- South Africa -- Eastern Cape , Climate change -- South Africa -- Eastern Cape
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:10633 , http://hdl.handle.net/10948/d1012857
  • Description: Cycads first appeared about 300 million years ago and historical data indicates that they survived fluctuations of global temperature and carbon dioxide concentrations and reached peak abundance during periods where temperature and carbon dioxide concentrations were much higher than the present conditions as well as the predicted increased levels. With Africa being one of the most vulnerable regions to climate change and in the absence of an evaluation of predicted impacts of climate change on cycads, this study aims to contribute to our understanding of responses of Encephalartos longifolius to increased temperature. Encephalartos longifolius (Jacq.) Lehm is an Eastern Cape endemic and like most cycads has been around for millions of years with very little change to its basic structure. Photosynthetic rates showed E.longifolius seedlings have C3 photosynthesis and even under stress they do not switch over to CAM photosynthesis. The photosynthetic rates of seedlings showed a typical C3 -plant type response under elevated carbon dioxide levels. Increased temperatures could be detrimental to the species but coupled with elevated carbon dioxide levels the growth of Encephalartos longifolius are postulated to outweigh the negative impacts of increased temperatures. Whilst climatic conditions in the Eastern Cape might not impact the abundance of Encephalartos longifolius, the species however is declining rapidly to the present near-threatened status. Demographic studies revealed a high percentage of juvenile numbers in the wild; however juvenile plants are impacted on by animals thereby jeopardizing their survival. Adult plants are heavily impacted on by animals; this reduces the probability of new offspring being produced. Cycads are also very slow - growing which is the primary cause of their ruin in the wild. Encephalartos longifolius grows at just over approximately 1 cm per year with growth being more rapid in the juvenile plants. Once juvenile plants reach approximately 60 cm they stop growing in diameter but only get taller. Seed germination is also a very slow process with an optimum temperature of 28°C and a growth medium of at least 50 percent moisture. Regardless of the Eastern Cape predicted to become the hottest province in South Africa as a result of climate change, cycads will be able to adapt to the changing environment and conservation plans should focus on animal and human impacts that are the major force causing decreasing abundance of Encephalartos longifolius in the wild.
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  • Date Issued: 2012

Post occupancy evaluation of an office building : the case of country club estate, Johannesburg

  • Authors: Matshili, Humbulani Emmanuel
  • Date: 2012
  • Subjects: Architectural design -- Evaluation , Offices -- Design , Office buildings -- South Africa -- Johannesburg -- Evaluation , Real property -- South Africa -- Johannesburg
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:9703 , http://hdl.handle.net/10948/d1018554
  • Description: Most organisations nowadays want to build offices that are cost effective, but at the same time they forget to consider the impact of IEQ on the occupants’ wellbeing and performance. These offices are equipped with air-conditioners, which may impact negatively on performances if not monitored, controlled and maintained. An occupant’s performance may be accelerated or reduced, based on the effectiveness of IEQ in the office buildings. It is imperative that the employer or management create a work environment that is conducive to the occupants’ needs, so that the occupants may be able to improve their work performance that often yields increased productivity. The main aim of the study was to investigate the efficiency of a building’s Indoor Environmental Quality (IEQ) and how it affects workers with regard to productivity. The objectives of the study were: to determine the level of satisfaction of the occupants in terms of the IEQ, evaluate the effects that the current IEQ of the building has on the productivity of the occupants, and proffer solutions to identified problems so that the building performance can be improved, and similar future buildings can be improved upon in terms of IEQ. Post Occupancy Evaluation (POE) was utilised to conduct the evaluation. This will help stakeholders and managements to ensure that past mistakes committed are not repeated in the future buildings. POE analyses IEQ related to Indoor Air Quality (IEQ), thermal comfort, occupant’s satisfaction and occupant performance and productivity. There is a correlation between different indoor parameters of the occupants’ satisfaction, health and productivity at the workplace. For these correlations to complement each other successfully, IEQ factors must be conducive to human wellbeing. Workplace environments are perceived as unsafe and unhygienic. This situation is caused by poor planning of workstations, low indoor air quality, inappropriate lighting in the office, lack of ventilation and insufficient safety measures. In particular, findings of this study demonstrate the low level of occupants’ satisfaction with regard to office buildings in the Country Club Estate, Johannesburg. The results from this study show that POE is perceived to be completely new to occupants of the Country Club Estate. Management or stakeholders have a huge task ahead to address the benefits of implementing POE and to face the consequences if POE is not implemented.
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  • Date Issued: 2012

Post-apartheid racial integration in Grahamstown : a time-geographical perspective

  • Authors: Irvine, Philippa Margaret
  • Date: 2012
  • Subjects: Race discrimination -- South Africa -- Eastern Cape Grahamstown (South Africa) -- Race relations Grahamstown (South Africa) -- Social conditions
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:4845 , http://hdl.handle.net/10962/d1005521
  • Description: This research is situated within the context of the post-apartheid era in South Africa, which includes the dominant ideologies and policies that have shaped the urban landscape of the past and present. It investigates the extent and patterns of integration that exist twenty years after the country’s political transition and it uses Grahamstown, a small education and cultural centre in the Eastern Cape Province, as its case study. The investigation incorporates the traditional geographical focus of residential and educational integration, using conventional means of investigation such as segregation indices, dissimilarity indices, percentages and maps. However, in identifying the broader nature of ‘segregation’ and ‘integration’, the study moves beyond these foci and approaches. It adopts the timegeographical framework to reveal the dynamic use of urban space that reflects the lived space of selected individuals from the community of Grahamstown: the extent and patterns of their behavioural integration or spatial linkages. Together, these approaches reveal that Grahamstown is still a city divided by race and, now, class. Schools and residential areas remain tied to the apartheid divisions of race and the white community exists almost entirely within the bounds of apartheid’s blueprint of urban space. Rhodes University, which is located within Grahamstown, has experienced admirable levels of integration within the student body and within the staff as a whole, but not within the staff’s different levels. In essence, where integration has occurred it has been unidirectional with the black community moving into the spaces and institutions formerly reserved for whites. The limited behavioural integration or spatial linkages are shown to be tied to city structure and, within the white group, to perceptions of ‘otherness’ held by the individuals interviewed. While the study shows limited differences in the time-spatial movements between members of different races who are resident in the former white group area, it highlights the differences between those more permanently resident in the city and the temporary educational migrants or students. The study argues that the slow pace of change is related to the nature of South Africa’s democratic transition and its attending political and economic policies.
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  • Date Issued: 2012

Pre-concentration of heavy metals in aqueous environments using electrospun polymer nanofiber sorbents

  • Authors: Darko, Godfred
  • Date: 2012
  • Subjects: Heavy metals -- Absorption and adsorption -- Research Nanochemistry -- Research Polystyrene -- Research Polyamides -- Research
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:4337 , http://hdl.handle.net/10962/d1004998
  • Description: This thesis presents an alternative approach for pre-concentrating heavy metals in aqueous environments using electro spun polymer nanofiber sorbents. The conditions for electrospinning polyethersulfone, polystyrene, polysulfone and polyamide-6 were optimized. The morphologies and porosities of the electrospun nanofibers were studied using SEM and BET nitrogen gas adsorptions. The nanofibers had mesoporous morphologies with specific surface areas up to 58 m2/g. The electro spun nanofiber sorbents were characterized in terms of their tunability for both uptake and release of heavy metals. The usability of the sorbent was also assessed. The sorbents showed fast adsorption kinetics for heavy metals « 20 min for As, Cu, Ni and Pb) in different aqueous environments. The adsorption characteristics of the sorbents best fitted the Freundlich isotherm and followed the first order kinetics. The efficiencies of adsorption and desorption of heavy metals on both imidazolyl-functionalized polystyrene and amino-functionalized polysulfone sorbents were more than 95% up to the fifth cycle of usage. Reusability improved dramatically (up to 10 runs of usage) when mechanically stable amino-functionalized nylon-6 electro spun nanofibers were used. The capacity of the amino-functionalized nylon-6 sorbent to pre-concentrate heavy metals compared very favourably with those of aqua regia and HN03+H202 digestions especially in less complex matrices. Due to their highly porous nature, the electro spun nanofibers exhibited high adsorption capacities (up to 50 mg/g) for heavy metal ions. The loading capacities achieved with the imidazolyl-functionalized sorbent were higher than those for amino-functionalized mesoporous silica and biomass-based sorbents. The electro spun nanofiber sorbents presents an efficient and cost effective alternative for preconcentrating heavy metals in aqueous environments.
  • Full Text:
  • Date Issued: 2012

Pre-concentration of toxic metals using electrospun amino-functionalized nylon-6 nanofibre sorbent

  • Authors: Darko, Godfrey , Sobola, Abdullahi O , Adewuyi, Sheriff , Okonkwo, J O , Torto, Nelson
  • Date: 2012
  • Language: English
  • Type: Article
  • Identifier: vital:6571 , http://hdl.handle.net/10962/d1004134
  • Description: This paper presents a new approach for pre-concentrating toxic metals (As, Cd, Ni and Pb) in aqueous environments using an amino-functionalized electrospun nanofibre sorbent. The sorbent, composed of nanofibres of average diameter 80 ± 10 nm and specific surface area of 58m2 g–1, exhibited fast adsorption kinetics (<20 min) for As, Cd, Ni and Pb. The optimalpHfor the uptake of As, Cd, Ni and Pb were 5.5, 6.0, 6.5 and 11, respectively. The adsorption process best fitted the Freundlich isothermand followed the first-order kinetics. The highest pre-concentration achieved using the sorbent was 41.99 (Ni in treated wastewater). The capacity of the sorbent to pre-concentrate the toxic metals was compared with those of aqua regia and HNO3+H2O2 digestions. The pre-concentration factors achieved for Cd in river water samples can be ranked as aqua regia digestion (0.73) > adsorption (0.34)>HNO3+H2O2 (0.23) digestion.Asimilar trend was observed for Ni in river water as well as Ni andCdin tap water samples. Pb ions in the river water samples were pre-concentrated slightly better using the two digestion methods pre-concentration factors ~22) compared to adsorption method (pre-concentration factor ~21). The use of the electrospun amino-functionalized nanofibre sorbent presentsanefficientand cost-effective alternative for pre-concentration of toxic metals inaqueousenvironments.
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  • Date Issued: 2012

Prediction of water temperature metrics using spatial modelling in the Eastern and Western Cape, South Africa

  • Authors: Rivers-Moore, Nick A , Mantel, Sukhmani K , Dallas, Helen F
  • Date: 2012
  • Language: English
  • Type: text , Article
  • Identifier: vital:7071 , http://hdl.handle.net/10962/d1003947 , http://www.scielo.org.za/scielo.php?pid=S1816-79502012000200002&script=sci_arttext
  • Description: Key aspects of a river's temperature regime are described by magnitudes, timing and durations of thermal events, and frequencies of extreme exceedance events. To understand alterations to thermal regimes, it is necessary to describe thermal time series based on these statistics. Classification of sites based on their thermal metrics, and understanding of spatial patterns of these thermal statistics, provides a powerful approach for comparing study sites against reference sites. Water temperature regime dynamics should be viewed regionally, where regional divisions have an inherent underpinning by an understanding of natural thermal variability. The aim of this research was to link key water temperature metrics to readily-mapped environmental surrogates, and to produce spatial images of temperature metrics: 37 temperature metrics were derived for 12 months of sub-daily water temperatures at 90 sites in the Eastern Cape and Western Cape provinces, South Africa. These metrics were correlated with 16 environmental variables. Correlations enabled development of multiple regression models which facilitated mapping of temperature metrics over the study area. This approach has the potential to be applied at a national scale as more thermal time series are collected nationally. It is argued that the appropriateness of management decisions in rivers can be improved by including guidelines for thermal metrics at a regional scale. Such maps could facilitate incorporation of a temperature component into management guidelines for water resources.
  • Full Text:
  • Date Issued: 2012

Prediction of water temperature metrics using spatial modelling in the Eastern and Western Cape, South Africa

  • Authors: Rivers-Moore, Nick A , Mantel, Sukhmani K , Dallas, Helen F
  • Date: 2012
  • Subjects: To be catalogued
  • Language: English
  • Type: text , report
  • Identifier: http://hdl.handle.net/10962/438180 , vital:73441 , ISBN 1816-7950 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/2651.pdf
  • Description: Key aspects of a river’s temperature regime are described by magnitudes, timing and durations of thermal events, and frequencies of extreme exceedance events. To understand alterations to thermal regimes, it is necessary to describe thermal time series based on these statistics. Classification of sites based on their thermal met-rics, and understanding of spatial patterns of these thermal statistics, provides a powerful approach for comparing study sites against reference sites. Water tem-perature regime dynamics should be viewed regionally, where regional divisions have an inherent underpinning by an understanding of natural thermal variability. The aim of this research was to link key water temperature metrics to readi-lymapped environmental surrogates, and to produce spatial images of temperature metrics: 37 temperature metrics were derived for 12 months of sub-daily water temperatures at 90 sites in the Eastern Cape and Western Cape provinces, South Africa.
  • Full Text:
  • Date Issued: 2012

Prevalence, seasonal trends and incidences of cattle tuberculosis and brucellosis in the Cacadu municipality, Eastern Cape, South Africa

  • Authors: Nombebe, Thobeka
  • Date: 2012
  • Subjects: Tuberculosis in cattle -- South Africa -- Eastern Cape , Brucellosis in animals -- South Africa -- Eastern Cape , Dairy farms -- South Africa -- Eastern Cape , Mycobacterium tuberculosis -- South Africa -- Eastern Cape
  • Language: English
  • Type: Thesis , Masters , MSc (Biostatistics and Epidemiology)
  • Identifier: vital:11783 , http://hdl.handle.net/10353/d1016200 , Tuberculosis in cattle -- South Africa -- Eastern Cape , Brucellosis in animals -- South Africa -- Eastern Cape , Dairy farms -- South Africa -- Eastern Cape , Mycobacterium tuberculosis -- South Africa -- Eastern Cape
  • Description: A cross-sectional study was conducted from February 2011 to August 2012 to investigate the status and identify risk factors for Bovine Tuberculosis (BTB) and cattle Brucellosis. A total of 1277 cattle from 6 selected dairy farms were tested. The farms were purposively selected on suspected risk. Samples were analysed using Rose Bengal Test (RBPT) and Complement Fixation Test (CFT) for Brucellosis and Comparative Intradermal Tuberculin Test (CITT) for BTB. The results revealed the overall prevalence of 1.6% for Brucellosis and no BTB was found. Logistic regression analysis revealed that age of cattle, herd size and number of calves a cow has had significant association with Brucellosis with p-values 0.0071, 0.0490 and 0.000 respectively. The role of location (p>0.05), gender (p>0.05) and breed (p>0.05) in the occurrence of the disease was not statistically significant at α=0.05, although higher rates were obtained in females and Jersey breed. Questionnaires were also administered to 47 individuals a total of 12 females and 35 males. Most respondents were not aware about cattle brucellosis and cattle tuberculosis. Consumption of raw or unpasteurized milk still occurs with 74.75% of respondents revealed.
  • Full Text:
  • Date Issued: 2012
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