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Intelligent monitoring and control system for a friction stir welding process

  • Authors: Kruger, Grant
  • Date: 2003
  • Subjects: Friction welding
  • Language: English
  • Type: Thesis , Masters , MTech (Electrical Engineering)
  • Identifier: vital:10823 , http://hdl.handle.net/10948/273 , Friction welding
  • Description: A Friction Stir Welding machine is proposed and built to allow future research into the process and to provide a framework from which the application of intelligent manufacturing to industrial processes can be investigated. Initially a literature survey was conducted upon which the design of the machine could be based. The conversion of a conventional milling machine into a Friction Stir Welding machine by applying modern monitoring and control systems is then presented. Complete digital control was used to drive actuators and monitor sensors. A wireless chuck mounted monitoring system was implemented, enabling forces, torques, temperature and speed of the tool to be obtained directly from the process. Software based on a hierarchical Open Systems Architectural design, incorporating modularity, interoperability, portability and extensibility is implemented. This experimental setup is used to analyze the Friction Stir Welding process by performing data analysis using statistical methods. Three independent variables (weld speed, spindle speed and plunge depth) were varied and the independent variables (forces, torques, power, temperature, speed, etc) recorded using the implemented software. The statistical analysis includes the analysis of variants, regression analysis and the creation of surface plots. Using these results, certain linguistic rules for process control are proposed. An intelligent controller is designed and discussed, using the derived rules to improve and optimize certain aspects of the process encountered during the experimental phase of the research.
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  • Date Issued: 2003

Intercohort cannibalism and parturition-associated behaviour of captive-bred swordtail, Xiphophorus helleri (Pisces: Poeciliidae)

  • Authors: Jones, Clifford Louis Wilshire
  • Date: 2003
  • Subjects: Poeciliidae -- Behavior Xiphophorus helleri Fish culture
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:5351 , http://hdl.handle.net/10962/d1007812
  • Description: Adult fish that belong to the family Poeciliidae cannibalise juveniles, both in the wild and under captive conditions, but this behaviour has only been partly investigated in the Poeciliidae in some of the commercially valuable species. The objective of the research is to develop an understanding of intercohort cannibalism and parturition-associated behaviour in captive-bred swordtail (Xiphophorus helleri), with applications to industry and future research of other poeciliids. Experiments investigating the effect of adult stocking density and sex ratio on the production of juveniles were used to determine if cannibalism occurs under culture conditions. The average rate of intercohort cannibalism ranged from (5.5 to 53.9%), and was positively density dependent and independent of sex ratio, indicating that males and females were probably equally cannibalistic. The highest number of juveniles (1725.7±141.4) produced per tank over 70 days was obtained from two males and eight females. To develop a better understanding of adult and juvenile behaviour during parturition, fish were observed under controlled laboratory conditions using video and behaviours such as attack (burst of speed by an adult in the direction of a juvenile), escape (avoidance of cannibalism after attack) and cannibalism (predation of a live juvenile by an adult), for example, were identified. Under laboratory conditions most young escaped in downward direction after attack (49%) and most utilised the refuge made that was made available. Furthermore, most attacks (62-65%) and cannibalism (57-84%) occurred at the bottom. Since the presence of refuge significantly increased the rate of juvenile survival under culture conditions, it was hypothesised that the rate of cannibalism could be reduced under farming conditions if juveniles were protected when they escaped downwards. This hypothesis was accepted as it was found that refuge at the bottom of the water column or the inclusion of a false-bottom reduced the rate of cannibalism by 49% and 72%, respectively. Similarly, the hypothesise that the rate of cannibalism could be reduced if juveniles where given protection when escaping sideways (32% of juveniles escaped sideways in the laboratory) was also accepted when tested under farm-scale conditions because a false-side reduced the rate of cannibalism by an average of 45%. Since males and females were equally responsible for cannibalising juveniles in the laboratory, it was hypothesised that the rate of cannibalism would decrease proportionately with the removal of males (Le. 20% of the cannibals) from the population; the removal of males under farming conditions resulted in a 19.5% reduction in the rate of cannibalism. Since older juveniles were better able to escape cannibalism than neonates and since adults habituate to stimuli that previously resulted in attack behaviour, it was hypothesised that the rate of cannibalism would remain unaffected by the length of time that juveniles were exposed to adults in the breeding tanks. This hypothesis was also accepted when tested under farm conditions. However, some hypotheses based on laboratory observations were not accepted. For example, a constant low light intensity did not appear to decrease the rate of cannibalism under farm conditions; also, the occurrence of dead and deformed juveniles went unnoticed in the laboratory, and under farm conditions, where adults did not have access to the bottom of the tank, 10% of the harvest consisted of dead and deformed juveniles. It is concluded that technologies, such as bottom-refuge or a false-side, that increase the size of the liveharvest and allow for the removal of potentially less viable offspring are recommended for the commercial production of poeciliids. The overall similarity of X. helleri behaviour between the laboratory experiments and the farm-scale trials suggests that the post-partum behaviour of X. helleri remains consistent under these different conditions; thus, behaviour under one set of conditions may be used to predict behaviour under other conditions. The application and significance of extrapolations to industry and future research of X. helleri and possibly other poeciliids were discussed and the most applicable laboratory observations with the highest extrapolation capacity were proposed. Furthermore, techniques were developed to aid industry and future researchers in making predictions relating to behaviour of X. helleri under different conditions based on laboratory observations. The results were used to develop a model indicating that selection pressures against cannibalism are not likely to exist at the rate of cannibalism observed here since the potential genetic gain through kin survival and inclusive fitness was shown to be greater than any potential genetiC loss experienced by a victim of cannibalism. The model was successfully tested under a range of social conditions. Other possible explanations for cannibalism in poeciliids, such as parental manipulation, nutritional advantages, opportunistic predation and the recovery of energy are discussed. It is suggested that the most likely proximate cause of cannibalism under captive conditions is opportunistic predation. The theory that cannibalism ensures that only viable genes of the victim are expressed, through inclusive fitness, is a possible ultimate cause of cannibalism, which may have been inherited from feral ancestors of captive-bred X. helleri.
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  • Date Issued: 2003

Interrogate the information society:

  • Authors: Berger, Guy
  • Date: 2003
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/159181 , vital:40275 , https://hdl.handle.net/10520/EJC146276
  • Description: If there is one thing journalists should know about the "Information Society", it's this: never use the phrase as if its meaning speaks for itself. This is one of the most slippery and contentious phrases yet to grace contemporary discourse. For a start, why "Information Society" and not "Knowledge Society"? And why "society" and not "economy"? This is not academic semantics. There are wholly different meanings at stake with different implications for journalists, politicians, policy makers and many more.
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  • Date Issued: 2003

Intervention in Bosnia-Herzegovina: lessons of peace‐maintenance for Africa?

  • Authors: Bischoff, Paul, 1954-
  • Date: 2003
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/161365 , vital:40620 , DOI: 10.1080/10220460309545430
  • Description: The Bosnian model is potentially a useful model for the development of a new strategic framework for African conflicts, particularly in situations where international organisations such as the United Nations are overstretched and regional organisations wish to take charge of peacebuilding operations.
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  • Date Issued: 2003

Introduction [to the book "Scatter the Shrilling Bones" by Sithembele Isaac Xhegwana]

  • Authors: Wright, Laurence
  • Date: 2003
  • Language: English
  • Type: text , article
  • Identifier: vital:7056 , http://hdl.handle.net/10962/d1007417
  • Description: preprint , Scatter the Shrilling Bones by Sithembele Xhegwana comprises an ordered sequence of poems that conveys a journey both literal and spiritual. Revisitation is the organizing principle of the collection – the return to rural sources and origins by a consciousness estranged and illumined by modernity (cf. ‘The Return’). Underlying the collection is the theme of the night journey, whose archetype in western culture is Odysseus’ descent to the underworld – a pattern identified as such in the concluding essay ‘Starting from my Place: Notes on an Aesthetic’. The underworld here is literally the return to the home territory – a journey from Cape Town to the rural Eastern Cape – but also a revisiting of the mental world of traditional Africa: ‘Here at home, here all guilt begins’ (‘Homecoming’). The return journey is haunted by nightmare memories of mental illness, the schizophrenic episodes accompanying (or occasioned by?) the poet’s initial encounters with modernity. This illness is represented as both pathological and cultural – a price paid for challenging and rejecting the old certainties while grappling with new assumptions: “He undermines the ancestors, That’s why he suffers. Let him.” (‘To Himself’)
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  • Date Issued: 2003

Investigation of the comparative cost-effectiveness of different strategies for the management of multidrug-resistant tuberculosis

  • Authors: Rockcliffe, Nicole
  • Date: 2003
  • Subjects: Tuberculosis , Multidrug resistance , Tuberculosis -- Treatment
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:3788 , http://hdl.handle.net/10962/d1003266 , Tuberculosis , Multidrug resistance , Tuberculosis -- Treatment
  • Description: The tuberculosis epidemic is escalating in South Africa as well as globally. This escalation is exacerbated by the increasing prevalence of multidrug-resistant tuberculosis (MDRTB), which is defined by the World Health Organisation (WHO) as resistance of Mycobacteria to at least isoniazid and rifampicin. Multi-drug resistant tuberculosis is estimated to occur in 1-2% of newly diagnosed tuberculosis (TB) patients and in 4-8% of previously treated patients. MDRTB is both difficult and expensive to treat, costing up to 126 times that of drug-sensitive TB. Resource constrained countries such as South Africa often lack both the money and the infrastructure to treat this disease. The aim of this project was to determine whether the performance of a systematic review with subsequent economic modelling could influence the decision making process for policy makers. Data was gathered and an economic evaluation of MDRTB treatment was performed from the perspective of the South African Department of Health. Three treatment alternatives were identified: a protocol regimen of second line anti-tuberculosis agents, as recommended in the South African guidelines for MDRTB, an appropriate regimen designed for each patient according to the results of culture and drug susceptibility tests, and non-drug management. A decision-analysis model using DATA 3.0 by Treeage® was developed to estimate the costs of each alternative. Outcomes were measured in terms of cost alone as well as the ‘number of cases cured’ and the number of ‘years of life saved’ for patients dying, being cured or failing treatment. Drug, hospital and laboratory costs incurred using each alternative were included in the analysis. A sensitivity analysis was performed on all variables in order to identify threshold values that would change the outcome of the evaluation. Results of the decision analysis indicate that the individualised regimen was both the cheaper and more cost-effective regimen of the two active treatment options, and was estimated to cost R50 661 per case cured and R2 070 per year of life saved. The protocol regimen was estimated to cost R73 609 per case cured and R2 741 per year of life saved. The outcome of the decision analysis was sensitive to changes in some of the variables used to model the disease, particularly the daily cost of drugs, the length of time spent in hospital and the length of treatment received by those patients dying or failing treatment. This modelling exercise highlighted significant deficiencies in the quality of evidence on MDRTB management available to policy makers. Pragmatic choices based on operational and other logistic concerns may need to be reviewed when further information becomes available. A case can be made for the establishment of a national database of costing and efficacy information to guide future policy revisions of the South African MDRTB treatment programme, which is resource intensive and of only moderate efficacy. However, due to the widely disparate range of studies on which this evaluation was based, the outcome of the study may not be credible. In this case, the use of a systematic review with subsequent economic modelling could not validly influence policy-makers to change the decision that they made on the basis of drug availability.
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  • Date Issued: 2003

Investigations into the asymmetric reduction of ketones

  • Authors: Bena, Luvuyo Clifford
  • Date: 2003
  • Subjects: Ketones , Asymmetric synthesis
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:11065 , http://hdl.handle.net/10948/323 , Ketones , Asymmetric synthesis
  • Description: A six-step synthesis of salbutamol from methyl salicylate with an overall yield of 17% has been completed, although the yield was not optimised. In the process, Zn(BH4)2 was found to selectively reduce a ketone carbonyl group in the presence of an ester unit. In contrast, borane was found to reduce both the ketone and ester carbonyl groups. Reduction of phenacyl bromide with borane in the presence of chiral catalysts based on (R)-alaninol and (R,S)-ephidrine resulted a measure of enantioselectivity in the product. However, the configuration of the alcohol obtained in the case of (R)-alaninol was contrary to expectations based both on experimental trends observed elsewhere as well as our own theoretical predictions. The asymmetric reduction of methyl 5-bromoacetyl-2-benzyloxybenzoate was accomplished with both borane and Zn(BH4)2 in the presence of a range of chiral catalysts. Optically active products were obtained in all cases, although the optical rotations were significantly smaller in the case of Zn(BH4)2. Unfortunately, we were not successful in determining the enantiomeric excesses of these reactions. The use of a NMR lanthanide shift reagent resulted in a complex spectrum that was impossible to interpret unambiguously. This presumably arises from the presence of several Lewis base sites in the product at which complexation with the shift reagent can take place. It was also not possible to determine the optical rotation of salbutamol itself owing to the relatively small amount of material obtained. A conformational analysis of salbutamol, where NMR data was correlated with molecular modelling results, was successfully carried out and revealed a strong preference for that conformer family characterised by O–C–C–N and Ar–C–C–N torsion angles of ca. 60º and 180º, respectively. Interestingly, these conformers are found to be stabilised by OH…N rather than NH…O hydrogen bonding. This study has also confirmed the effectiveness of the MMFF94 force field for conformational analysis studies in compounds of this kind. Lastly, a relatively simple method for modelling the BH3/oxazaborolidine reduction of ketones at the PM3 semiempirical MO level of approximation was devised. This approach has provided insights into the mechanism of the reaction and has furthermore enabled us to predict the enantioselectivities likely to result from various catalysts and ketones. In comparing our theoretical and experimental findings, an anomalous result was observed in the case of (R)-alaninol; this will have to be investigated further, particularly at the experimental level. However, we believe that our approach provides a sound basis for aiding the design and screening of new, potentially better catalysts.
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  • Date Issued: 2003

IsiXhosa insect names from the Eastern Cape, South Africa

  • Authors: Mkize, N , Villet, Martin H , Robertson, M P
  • Date: 2003
  • Language: English
  • Type: Article
  • Identifier: vital:6859 , http://hdl.handle.net/10962/d1011148
  • Description: We present a list of isiXhosa names for a wide diversity of South African insects, and their English translations and scientific names, to contribute to bridging the knowledge gap between rural development workers and isiXhosa speakers. We interviewed 51 people in their homes at eight sites across the Eastern Cape and also included words from a published dictionary. We found 151 insect names, and categorized them into personal, dialectal and standard categories. Response-frequency distributions of the categories of names showed that the dialectal and standard lists were essentially complete. Sample accumulation curves showed levelling-off within sites and across the whole study, demonstrating that samples were adequate. The literal translations of some names show that isiXhosa speakers relate insects either to people, to their habitat and/or to their behaviour. The list can contribute to the standardization of knowledge of insects' indigenous names in South Africa for a variety of practical applications such as agricultural training and health services.
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  • Date Issued: 2003

Isolation of antigenic peptides of Cowdria ruminantium and their encoding genes using a genome-derived phage display library

  • Authors: Fehrsen, Jeanni
  • Date: 2003
  • Subjects: Bacteriophages -- Genetics Ruminants -- Diseases Heartwater
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:3920 , http://hdl.handle.net/10962/d1003979
  • Description: The development of new and effective vaccines and immunodiagnostic reagents requires the characterisation of antigenically relevant proteins and their interactions with the products of the immune system. Phage display technology was investigated as a means of elucidating some of the antigenic properties of the rickettsial parasite, Cowdria ruminantium (Cowdria). Randomly fragmented gene-derived libraries have been useful in elucidating viral and other epitopes, but only limited work has been done with entire genomes. A phage display library expressing a repertoire of Cowdria peptides was constructed. It was sufficiently large to represent the organism's genome, but lacked phages displaying peptides coded for by genes containing a Pvu II restriction enzyme site, including the one coding for the major antigenic protein 1 (MAP1). This was considered advantageous since MAP1 is immunodominant and has already been well characterised. Affinity selection with antibodies against Cowdria proteins other than MAP1 allowed several antibody-reactive peptides to be isolated. These selected sequences were placed in the context of the genome by screening a lambda bacteriophage library and by comparison with Cowdria DNA sequences. Apart from showing that antigenic mimics were present in the phage display library, six open reading frames encoding putative Cowdria proteins were identified. All had similarities to, or motifs in common with, membrane proteins and are thus likely to be exposed to the host's humoral immune system. Some of the proteins identified were larger than the antigens used to elicit the antibodies used for selection, probably as a result of the presence of cross-reactive epitopes. Despite limitations experienced when extending a fragmented-gene approach for epitope location to genomes, it was possible to identify an antigenic region on MAP1 by comparison with selected mimics. In addition, binding peptide sequences were identified with two monoclonal antibodies that had been raised against non-Cowdria antigens. An epitope on the VP7 protein of bluetongue virus was identified and peptides were found that reacted with a monoclonal antibody directed against malignant catarrhal fever virus. Thus, apart from being able to identify several potentially important Cowdria epitopes and genes, the fragmented-genome library holds promise as a universal reagent for identifying useful mimics.
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  • Date Issued: 2003

Isolation, expression and purification of the hydantoin hydrolysing enzymes of agrobacterium tumefaciens

  • Authors: Clark, Sally-Ann
  • Date: 2003
  • Subjects: Agrobacterium tumefaciens , Amino acids Hydantoin Enzymes
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4140 , http://hdl.handle.net/10962/d1016233
  • Description: The production of enantiomerically pure amino acids is of industrial importance as they are used in the synthesis of a number of pharmaceuticals, insecticides and herbicides and biologically active peptides and hormones. A number of microorganisms have been identified which possess hydantoin hydrolysing enzymes that stereoselectively convert racemic hydantoins into anantiomerically pure amino acids. Consequently these microorganisms and their enzymes are sought after as biocatalysts for the production of amino acids. The isolation of novel hydantoin hydrolising enzymes with unique or improved biocatalytic characteristics is of importance for the development of potential biocatalysts to be used in the production of enantiomerically pure amino acids. The genes encoding an N-carbamoyl-amino acid amidohydrolase, an enzyme involved in the hydrolysis of hydantoin, was isolated by screening a genomic DNA library of Agrobacterium tumefacience RU-AE01. Nucleotide sequence analysis of the region upstream of this gene revealed a fragment of a gene encoding the hydantoinase enzyme. I this study, a DNA probe consisting of the gene encoding the N-carbamoyl amino acid amidohydrolase, on a large enough fragment of the genomic DNA library which would allow for the simultaneous isolation the hydantoinase gene located upstream. Recombinant expression of the genes encoding hydantoin hydrolysing enzymes has been used to facilitate the production and purification of these enzymes for their use as biocatalysts. Two genes (ncaR1 and ncaR2) encoding different N-carbamoyl-amino acid amidohydrolases with distinct nucleotide and deduced amino acid sequences were isolated from the genome of A, tumefaciens RU-OR. In this study, the heterologous expression of ncaR1 and ncaR2 was explored. Investigation into the optimisation of the heterologous expression of ncaR1 showed that reducing the growth temperature of the recombinant E. coli producing NcaR1 resulted in a two-fold increase in N-carbamoyl-amino acid amidohydrolase activity and solubility. Furthermore, NcaR1 was produced with a C-terminal 6xHis tag, but NcaR1-6xHis did not possess N-carbamoyl amino acid amidohydrolase activity. Furthermore, purification of NcaR-6xHis under native conditions using affinity chromatography performed, and used for the production of antibodies.
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  • Date Issued: 2003

Jane Austen re-visited a feminist evaluation of the longevity and relevance of the Austen Oeuvre

  • Authors: Kollmann, Elizabeth
  • Date: 2003
  • Subjects: Austen, Jane, 1775-1817 -- Criticism and interpretation , Feminist literary criticism
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:10994 , http://hdl.handle.net/10948/299 , Austen, Jane, 1775-1817 -- Criticism and interpretation , Feminist literary criticism
  • Description: Although many might consider Jane Austen to be outdated and clichéd, her work retains an undying appeal. During the last decade the English-speaking world has experienced an Austen renaissance as it has been treated to a number of film and television adaptations of her work, including Pride and Prejudice, Emma, Mansfield Park and Sense and Sensibility. Film critics such as Bill De Lapp (1996) and Sherry Dean (1996) have commented on the phenomenal response these productions received and have been amazed by Austen’s ability to compete with current movie scripts. The reasons for viewers and readers enjoying and identifying with Austen’s fiction are numerous. Readers of varying persuasions have different agendas and hence different views and interpretations of Austen. This thesis follows a gynocritical approach and applies a feminist point of view when reading and discussing Austen. Austen’s novels - Pride and Prejudice, Mansfield Park, Emma, Northanger Abbey, Sense and Sensibility, and Persuasion – are re-read and reevaluated from a feminist perspective in order to call attention to Austen’s awareness of women’s second-class position in her society. Women’s experiences in Austen’s time are compared to women’s experiences in society today in order to illustrate, in some way, the tremendous progress the feminist movement has made. In addition, by examining what Austen reveals about the material reality of women in her time, it is possible to explore the legacy that modern women have inherited. Literary critics such as André Brink (1998), Claudia Johnson (1988), and Gilbert and Gubar (1979) believe Austen to create feminist awareness in her novels. There are critics, however, who do not view Austen as necessarily feminist in her writing. Nancy Armstrong writes in Desire and Domestic Fiction (1987) that Austen’s objective is not a critique of the Abstract iv old order but rather a redefinition of wealth and status. In Culture and Imperialism (1993) Edward Said implicates Austen in the rationale for imperial expansion, while Barbara Seeber argues in “The Schooling of Marianne Dashwood” (1999) that Austen’s texts should be understood as dialogic. Others, such as Patricia Beer (1974), believe Austen’s fiction primarily to be about marriage since all her novels end with matrimony. My own reading of Austen takes into consideration her social milieu and patriarchal inheritance. It argues that Austen writes within the framework of patriarchy (for example by marrying off her heroines) possibly because she is aware that in order to survive as a woman (writer) in a male-favouring world and in a publishing world dominated by men, her critique needs to be covert. If read from a feminist perspective, Austen’s fiction draws our attention to issues such as women’s (lack of) education, the effects of not being given access to knowledge, marriage as a patriarchal institution of entrapment, and women’s identity. Her fiction reveals the effects of educating women for a life of domesticity, and illustrates that such an education is biased, leaving women powerless and without any means of self-protection in a male-dominated world. Although contemporary women in the Western world mostly enjoy equal education opportunities to men, they suffer the consequences of a legacy which denied them access to a proper education. Feminist writers such as Flis Henwood (2000) show that contemporary women believe certain areas of expertise belong to men exclusively. Others such as Linda Nochlin (1994) reveal that because women did not have access to higher education for so many years, they failed to produce great women artists like Chaucer or Cézanne. Austen’s fiction also exposes the economic and social system (of which education constitutes a major part) for enforcing marriage and for enfeebling women. In addition, it illustrates some of the realities and pitfalls of marriage. While Austen only subtly refers to Abstract v women’s disempowerment within marriage, contemporary feminist scholars such as Germaine Greer (1999) and Arnot, Araújo, Deliyanni, and Ivinson (2000) explicitly warn women that marriage is a patriarchal institution of entrapment and that it often leaves women feeling unfulfilled. The issue of marriage as a patriarchal institution has been thought important and has been addressed by feminists because it contributes to women’s powerlessness. Feminist scholars today find it imperative to expose all forms of power in order to eradicate women’s subordination. bell hooks comments in Feminist Theory: From Margin to Center (2000) on the importance of revealing unfair power relations in order to eliminate oppression of any kind. Austen does not necessarily express the wish to eradicate forms of power or oppression in her novels. Yet, if we read her work from a feminist point of view, we are made aware of the social construction of power. From her fiction we can infer that male power is enshrined in the very structure of society, and this makes us aware of women’s lack of power in her time. Austen’s novels, however, are not merely novels of powerlessness but of empowerment. By creating rounded women characters and by giving them the power to judge, to refuse and to write, Austen challenges the stereotyped view of woman as either overpowering monster or weak and fragile angel. In addition, her novels seem to question women’s inherited identity and to suggest that qualities such as emotionality and mothering are not natural aspects of being a woman. Because she suggests ways in which women might empower themselves, albeit within patriarchal parameters, one could argue that she contributes, in a small way, to the transformation of existing power relations and to the eradication of women’s servile position in society.
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  • Date Issued: 2003

Judicial enforcement of socio-economic rights under the 1996 constitution : realising the vision of social justice

  • Authors: Ngcukaitobi, T
  • Date: 2003
  • Subjects: South Africa. Constitution , South Africa. Bill of Rights , Civil rights -- South Africa , Human rights -- South Africa , South Africa -- Politics and government -- 1994- , South Africa -- Economic conditions -- 1991- , South Africa -- Social conditions -- 1994-
  • Language: English
  • Type: Thesis , Masters , LLM
  • Identifier: vital:3689 , http://hdl.handle.net/10962/d1003204 , South Africa. Constitution , South Africa. Bill of Rights , Civil rights -- South Africa , Human rights -- South Africa , South Africa -- Politics and government -- 1994- , South Africa -- Economic conditions -- 1991- , South Africa -- Social conditions -- 1994-
  • Description: Few legal developments in South Africa and elsewhere in the world in recent times have excited such controversy as the legal recognition of social and economic rights. South Africa has created a special place for itself in world affairs for being one of the countries that recognise socio-economic rights in a justiciable Bill of Rights. Partly this is in response to the appalling levels of poverty prevalent in the country which could potentially destabilise the new democracy. Improvement of the quality of life of every citizen is a crucial step in consolidating the constitutional democracy. The question that will face any court in giving effect to socio-economic rights is: how are these rights to be judicially enforced in a given context? The crux of this thesis lies in the resolution of this question. Firstly this thesis traces the philosophical foundations to the legal recognition of socio-economic rights. It is stated that the recognition of these rights in a justiciable bill of rights requires a conceptually sound understanding of the nature of obligations that these rights place on the state. It is emphasised that it is imperative that access to justice be facilitated to poor and vulnerable members of society for the realisation of the constitutional goal of addressing inequality. Particular concern and priority should in this context be given to women, children and the disabled. The study explores various judicial remedies and makes suggestions on new and innovative constitutional mechanisms for judicial enforcement of these rights. It is concluded that there is an important role to be played by civil society in giving meaningful effect to socio-economic rights.
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  • Date Issued: 2003

Labour law implications of organisational restructuring

  • Authors: Grootboom, Linda Henry
  • Date: 2003
  • Subjects: Labor laws and legislation -- South Africa , Organizational change -- South Africa
  • Language: English
  • Type: Thesis , Masters , LLM
  • Identifier: vital:11041 , http://hdl.handle.net/10948/303 , Labor laws and legislation -- South Africa , Organizational change -- South Africa
  • Description: It is beyond debate that each job lost due to restructuring means a lost taxpayer, and hence lost tax revenue, more poverty and increased crime. South Africa and the world at the large have to deal with this problem head – on in view of the acute need to better the lives of people and encourage investment. Technological advancement should be embraced and used to benefit people and stimulate economies, and that is further challenge in its own right. In Chapter 8 of the White Paper on Transformation of the Public Service dated 15 November 1995 (hereinafter, the White Paper), it is said that: “The Government of National Unity has embarked upon a concerted and comprehensive programme of administrative restructuring and rationalisation (my emphasis) with the object of: (a) Creating a unified and integrated service. (b) Creating a leaner and more cost-effective service.” Various strategies are listed in the White Paper, and the fundamental approach advocated is to right size, adjust remuneration structures, retrench and contract – out services.
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  • Date Issued: 2003

Language and value : the place of evaluation in linguistic theory

  • Authors: Kilpert, Diana Mary
  • Date: 2003
  • Subjects: Linguistics -- Philosophy Systemic grammar Discourse analysis English language -- Standardization Linguistic analysis (Linguistics) Functionalism (Linguistics) Halliday, M. A. K. (Michael Alexander Kirkwood), 1925- Chomsky, Noam Labov, William Pinker, Steven, 1954- Harris, Roy, 1931-
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:2353 , http://hdl.handle.net/10962/d1002635
  • Description: It is a central claim of modern linguistic theory that linguists do not prescribe, but describe language as it is, without pronouncing on correctness or judging one variety better than another. This attempt to exclude evaluation is motivated by a desire to be ' politically correct', which hinders objective analysis of language, and by an ill-advised imitation of the natural sciences, which obstructs the discipline's progress towards becoming a science in its own right. It involves linguists, as users of a valued variety, in self-deception and disingenuousness, distances them from the concerns of the ordinary language user, and betrays a failure to understand the involvement of social values in language, the nature of language itself, and the limits of linguistic science. On a wider scale, linguistics reflects society's devaluing and mechanisation of language. Despite growing concern expressed in the literature, and the incoherence that becomes apparent when linguists attempt to address social problems using a theory that regards language as an autonomous object, newcomers to the discipline continue to be taught that anti-prescriptivism is the natural corollary of a scientific approach to language. This thesis suggests that the way out of these difficulties is to rethink the meaning of ' theory' in linguistics. If we take the reflexivity of language seriously, building on M.A.K. Halliday's notion of 'linguistics as metaphor', we are reminded that a linguistic theory is made of language. Metalanguage must use the experiential and interpersonal meaning-making resources of everyday language. It follows that a linguistic theory cannot escape being evaluative, because evaluation is an inherent part of interpersonal meaning. If we fail to notice our own metalinguistic evaluation, this is because language disguises its evaluative meanings, or perhaps we are just not used to thinking of them as part of the grammar. To achieve clarity about the involvement of value in language, we need to turn our metalanguage back on itself - 'using the grammar to think with about the grammar' . Some ways of doing this are demonstrated here, turning the resources of systemic functional linguistics on linguists' own language. The circularity of this process should be seen not as a drawback but as a salutary reminder that linguistics is an interpretive rather than a discovery process. This knowledge should help us revalue language and make a place for evaluation in linguistic theory, paving the way for a socially responsible and productive linguistics.
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  • Date Issued: 2003

Locating the institution of traditional leadership within the institutional framework of South Africa's new democracy

  • Authors: Mashele, Hlukanisa Prince
  • Date: 2003
  • Subjects: Tribal government -- South Africa , Political leadership -- South Africa , South Africa -- Politics and government -- 1994-
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:2858 , http://hdl.handle.net/10962/d1007512 , Tribal government -- South Africa , Political leadership -- South Africa , South Africa -- Politics and government -- 1994-
  • Description: This study looks into the role of the institution of traditional leadership in post-apartheid South Africa. It seeks to critically engage the debate on how to locate the institution within the new politico-constitutional framework. This is done with the main objective of proposing an altemative to the current state of affairs vis-à-vis traditional leadership and governance in South Africa. In order to clear the ground, the study first deals with the important question of democracy in relation to the institution of traditional leadership. In this regard, the study unearthed that the institution of traditional leadership is fundamentally undemocratic in character, as it is largely based on heredity and devoid of principles of democracy such as equality, accountability, etc. In order to put matters into perspective the study also delves into the history of the institution of traditional leadership with the aim of getting to the role that traditional leaders played in various epochs of South Africa's political development. This investigation reveals that the denting of the integrity of the institution of traditional leadership began with the advent of colonialism and worsened by successive apartheid regimes. It is at these stages of development that the institution was subordinated to a higher authority that sought to use the institution as an instrument of domination and oppression of the black majority. Considering this role, it would seem that the place that the space that the institution occupies in the post-apartheid South African governance framework is a compromise. The institution plays an advisory role at all levels of government - with their houses in both national and provincial legislatures, whilst traditional leaders sit as ex-officio members on local councils. However, traditional leaders fiercely contest this position as, in their view, this limits their powers. The main argument of this study is that for traditional leaders to be given an advisory role in the current and future governance framework of the country is a step in the right direction, as that serves to insulate the institution from active politics. For that reason, the study recommends that the institution of traditional leadership should occupy a cultural space in society - meaning that it should be responsible for the preservation of African customs and culture. This, therefore, means that the institution is better-placed to advise government on cultural and customary aspects of development. Whilst playing this role, the institution of traditional leadership should also -be brought into line with democratic ways of governance.
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  • Date Issued: 2003

Marketing fresh venison in the Eastern Cape Province using a niche marketing strategy

  • Authors: Bull, Gregory Simon
  • Date: 2003
  • Subjects: Market segmentation , Venison -- Marketing , Meat industry and trade -- South Africa -- Eastern Cape
  • Language: English
  • Type: Thesis , Masters , MTech (Marketing)
  • Identifier: vital:10765 , http://hdl.handle.net/10948/136 , Market segmentation , Venison -- Marketing , Meat industry and trade -- South Africa -- Eastern Cape
  • Description: There is a need in the Eastern Cape Province to expand the market for fresh venison. This need is due in part to fluctuations in the export market and fragmentation of consumption in the food industry, which has led to an increased demand for specialised and customised products. A suitable method for addressing these issues and successfully marketing fresh venison in the Eastern Cape Province was required, and based on the findings of this study, niche marketing was found to be a possible marketing method to explore. This study evaluated how a strategy of niche marketing could be used to market fresh venison within the Eastern Cape Province. By analysing this main problem the research attempted to identify and understand the challenges of marketing fresh venison to the final consumer in the Eastern Cape Province and to determine whether niche marketing would be a viable option when taking into account venison’s unique characteristics. Niche marketing was characterised and discussed in the light of other marketing approaches and the most important elements of a successful niche marketing strategy were highlighted. The information resulting from scrutiny of all of these sub-problems was then used to address the challenge of marketing fresh venison to the final consumer. In-depth interviews were deemed most suitable for this study based on the nature of the topic and the depth of expertise of qualified personnel in the Eastern Cape Province fresh venison industry. Consequently, four interviews were conducted with experts in the field. Using the niche marketing concept and the strategy that drives it, namely differentiation, possible niche markets were identified. A strategy of multiple niching was adopted to address the differentiation opportunities available, based on the relevant specialist roles of fresh venison. These differentiation opportunities in turn lead to competitive advantage. Possible niche target markets identified and analysed included the tourist market, travellers (foreign and local) by air and sea, the organic aware market and the pet food market. Branding was found to be an integral element for the niche marketing of venison and is also discussed. The main problems hindering fresh venison marketing in the Eastern Cape Province were found to be consumers’ lack of knowledge of venison, cultural differences and consumer preferences, lack of a formal infrastructure and control, and a lack of accurate data. These challenges need to be addressed before fresh venison can be successfully marketed in the Eastern Cape Province. Research needs to be conducted on the venison industry and formal supply chains and control channels need to be implemented before a quality product in substantial and consistent quantities can be successfully marketed to the final consumer. Consumers and industry personnel must be educated about venison and its merits, and fresh venison must initially target white tablecloth restaurants and specialised delicatessens, where service is as important as the product itself.
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  • Date Issued: 2003

Media and parliament in the Third Republic: a study of newspaper coverage of parliament by the Times of Zambia and the Post from January to November 2001

  • Authors: Djokotoe-Gliguie, Edem K
  • Date: 2003
  • Subjects: Newspapers -- Zambia Mass media -- Political aspects -- Zambia Zambia -- Politics and government
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:3515 , http://hdl.handle.net/10962/d1007796
  • Description: The press is credited with playing a central role in the consolidation of democracy by informing citizens, engaging them in the process of public decision making and governance and stimulating wide and inclusive debate on public matters. In emergent democracies like Zambia, the extent of the media's role as a public sphere, not to mention its impact, is not known. The study set out to investigate the extent of the press' public sphere role, particularly how Zambian newspapers report Parliament and how such coverage informs public opinion. It found that though the press covers Parliament, the nature of coverage does not empower newspaper readers with the kind of context, background and interpretation they would otherwise need to engage in public discourses on matters that affect them from an informed perspective. In the main, the role of the press in informing citizens is not fully realised, not only because uninformative character of coverage, but partly because of low literacy levels and the limited reach of local newspapers. It was against this background that the study recommended ways in which the Zambian press could re-focus its approach to parliamentary news coverage to make it more informational and more inclined towards playing a public sphere role, at least to the newspaper-reading public. Making parliamentary coverage an integrated newsroom function was the main recommendation. It provided the basis for suggesting a practical editorial option for the coverage of the legislature that accommodates the integration of context, background and interpretation into parliamentary news.
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  • Date Issued: 2003

Mesozooplankton community structure and grazing impact in the polar frontal zone of the Southern Ocean

  • Authors: Bernard, Kim Sarah
  • Date: 2003
  • Subjects: Zooplankton -- Antarctic Ocean , Copepoda -- Feeding and feeds
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5731 , http://hdl.handle.net/10962/d1005417 , Zooplankton -- Antarctic Ocean , Copepoda -- Feeding and feeds
  • Description: Mesozooplankton community structure and grazing impact in the Polar Frontal Zone (PFZ) of the Southern Ocean were investigated during two cruises of the South African National Antarctic Programme (SANAP), the Marion Offshore Ecosystem Variability Study I & II (MOEVS). During the first cruise (MOEVS I), a meso-scale oceanographic grid survey was conducted in the upstream region of the Prince Edward Islands (PEI) in austral autumn (April) 2001. Mesozooplankton samples, collected using a Bongo net (fitted with 200 and 300µm mesh nets) at depths between 200 and 300 m, were separated into three size fractions: 200-500 µm; 500-1000 µm; 1000-2000 µm by reverse filtration. Total surface (depth <5 m) chlorophyll-a (chl-a) concentration (measured fluorometrically) during the study ranged between 0.11 and 0.34 µg 1^(-1) and was always dominated by picophytoplankton (<2.0 µm). Total mesozooplankton abundance and biomass during the survey ranged between 49 and 1512 ind. m^(-3) and between 0.7 and 25 mg Dwt. m^(-3), respectively. Throughout the survey, the 200-500 µm class numerically dominated the mesozooplankton community, comprising an average of ~ 69% (SD = ± 12.3%). The dominant species in the 200-500 µm size fraction were the copepods Oithona similis, Calanus simillimus and Metridia lucens and the pteropod, Limacina retroversa. However, in terms of biomass, the 1000-2000 µm group was predominant, with dry weight values constituting an average of ~ 66% (SD = ± 10.2%). Biomass was dominated by carnivorous zooplankton, particularly the euphausiids, Euphausia vallentini and Thysanoessa vicina and the chaetognaths, Sagitta gazellae and Eukrohnia hamata. Three distinct groupings of stations were identified by multivariate analysis. The different station groupings identified reflect changes in the relative contributions of the rather than different species assemblages. During the second cruise (MOEVS II), conducted in April 2002 (austral autumn), mesozooplankton community structure and grazing impact were investigated at 13 stations in the west Indian sector of the PFZ. Total integrated chl-a biomass ranged between 11.17 and 28.34 mg chl-a m^(-2) and was always dominated by nano- and picophytoplankton (<20 µm). Throughout the study, small copepods, mainly Oithona similis and Ctenocalanus vanus, numerically dominated the mesozooplankton community comprising up to 85% (range 30 to 85%) of the total abundance. Grazing activity of the four most abundant copepods (O. similis, C. vanus, Calanus simillimus and Clausocalanus spp.), which comprised up to 93% of total mesozooplankton abundance, was investigated using the gut fluorescent technique. Results of gut fluorescence analyses indicated that C. simillimus, Clausocalanus spp. and Ctenocalanus vanus exhibited diel variability in gut pigments, with maximum values at various stages of the night. In contrast, O. similis did not demonstrate diel variation in gut pigment contents. Ingestion rates of the four copepods ranged from 23.23 to 1462.02 ng (pigm.) ind^(-1) day^(-1), depending on the species. The combined grazing impact of the four copepods, ranged between 1 and 36% of the phytoplankton standing stock per day, with the highest daily impact (~ 35.86%) occurring at stations in the vicinity of the Antarctic Polar Front. Among the copepods, O. similis and C. vanus were generally the most important consumers of phytoplankton biomass; together they were responsible for up to 89% (range 15 to 89%) of the total daily grazing impact. Carbon specific ingestion rates of the copepods varied between 42 and 320% body carbon per day, depending on the species. The study highlights the importance of small copepods in terms of both their significant contribution to total mesozooplankton numbers and their grazing impact on the phytoplankton standing stocks in the PFZ during austral autumn.
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  • Date Issued: 2003

Metal interactions with neural substrates and their role in neurodegeneration

  • Authors: Lack, Barbara Anne
  • Date: 2003
  • Subjects: Nervous system -- Degeneration Neurotoxicology Chemical reactions Metals -- Physiological effect Melatonin -- Physiological effect
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:4391 , http://hdl.handle.net/10962/d1005709
  • Description: "Life" may be characterized as a controlled stationary flow equilibrium, maintained by energy consuming chemical reactions. The physiological functioning of these life systems include at least 28 of the elements isolated on the periodic table thus far, most of which are metals. However, as with Paracelsus Principle: "The dose makes the poison", there exists a definite link between metal levels, essential and toxic, and the onset of neurodegenerative diseases. The economic costs of brain dysfunction are enormous, but this pales in comparison to the staggering emotional toll on the victims themselves and their families. In an attempt to improve the understanding of the causes of neurodegeneration, this study focuses on one potential aspect: the possible link between metals and neurotransmitter homeostasis utilising a variety of electronanalytical techniques. Adsorptive cathodic stripping voltammetry was employed to investigate the binding affinities and complex formation of melatonin and its precursor serotonin with calcium, potassium, sodium, lithium and aluminium. The results showed that all the metals studied formed complexes with both pineal indoleamines. However, the stability and affmity of the ligands toward the various metals varied greatly. The study suggests a further role for melatonin, that of metalloregulator and possible metal detoxifier in the brain, the in vivo studies which followed will further substantiate this notion. This research additionally focused on the cholinergic system, in particular acetylcholine complex formation studies with mercury, lead, cadmium, copper and zinc using the adsorptive cathodic stripping voltammetry method. The formation and characterisation of a solid mercury-acetylcholine complex lent further strength to the in situ electrochemical complex formation observed. The results showed the preference of acetylcholine for environmentally toxic heavy metals (such as Cd²⁺) over those divalent cations that occur naturally in the body. The possible metalloregulatory role melatonin played in the three brain regIOns: cerebellum, cortex and corpus striatum of male Wistar rats was studied as an in vivo extension of the earlier in vitro studies. Anodic stripping voltammetry was employed to detect metal levels present. The results showed that daily injections of melatonin was responsible for significantly decreasing copper(I), cadmium(II) and lead(II) levels in various regions of the rat brain of those animals that had undergone a pinealectomy in comparison to the saline injected group having undergone the same treatment. Histological and electrochemical stripping techniques were applied to investigate the implications of high A1³⁺ levels in the brain regions, particularly the hippocampus. Melatonin showed signs of promise in indirect symptom alleviation and by significantly decreasing A1³⁺ levels in rats that had been dosed with melatonin prior to A1³⁺ treatments in comparison with the control groups. Finally a preliminary study outlining a method for the production of a calcium selective microelectrode was undertaken. Further work is still needed to optimise the microelectrode production as well as its possible applications. However, whilst the overall conclusions of this entire multidisciplinary study may indeed only be in effect one piece of a very large puzzle on neurodegenerative diseases, this piece will no doubt serve as a building block for further ideas and work in this field.
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  • Date Issued: 2003

Metallophthalocyanine derivatives as catalysts for the detection of sulphur dioxide, cyanide, nitrite and amino acids

  • Authors: Thamae, Mamothibe Amelia
  • Date: 2003
  • Subjects: Cyanides Nitric oxide Electrochemistry Nitrites Suplhur dioxide Amino acids
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:4295 , http://hdl.handle.net/10962/d1004542
  • Description: Electrocatalytic reduction and oxidation of nitrite using cobalt phthalocyanine derivatives was studied. The detection limit of 1 x 10⁻¹° mol dm⁻³ was achieved when these molecules were employed as catalysts for nitrite detection. The mechanisms for nitrite catalysis were proposed. The position of the peripheral substituents on cobalt porphyrazines (related to cobalt phthalocyanines) affected the catalytic activity of these complexes. The highest activity for nitrite reduction was observed on the cobalt(II) 2,3-tetramethyltetrapyridinoporphyrazine ([CoTm-2,3-tppa]⁴⁺), with cobalt phthalocyanine showing the lowest activity, and the cobalt(II) 3,4- tetramethyltetrapyridinoporphyrazine ([CoTm-3,4-tppa]⁴⁺), showing intermediate behaviour. A mixture of a negatively charged cobalt(II) tetrasulfophthalocyanine ([Co¹¹TSPc]⁴⁻) and a positively charged [CoTm-3,4-tppa]⁴⁺ showed better activity for nitrite reduction than did the individual components. Cobalt porphyrazines lowered the potentials for nitrite reduction in that peaking was observed, as opposed to cobalt phthalocyanine, where only the increase in currents was observed without peaking. Using the cobalt phthalocyanine derivatives, nitrite can be reduced to ammonia with high current efficiency. A glassy carbon electrode modified with [Co¹¹TSPc]⁴⁻ was employed for the determination of nitrite. Nitrate had an insignificant effect on nitrite oxidation on these modified electrodes. Electrocatalytic determination of S0₂ was studied as a function of pH at a glassy carbon electrode modified with iron(II) tetrasulfophthalocaynine. It was found that depending on pH, S0₂.xH₂0, HS0₃⁻ and/or SO₃²⁻ are the main compounds in solution and that these compounds behave differently at the electrode surface. Detection limits ranging from 4.0 ± 0.1 x 10⁻⁵ to 7.5 ± 0.1 x 10⁻⁵ mol dm⁻³ depending on pH were observed. Similar results were obtained when cobalt(II) tetrasulfophthalocaynine was employed for S0₂ catalysis under the same experimental conditions. Cysteine and histidine determination using oxidation currents was performed on glassy carbon electrodes modified with [CoTm-3,4-tppa]⁴⁺ (represented as [CoTm-3,4-tppa]⁴⁺-GCE) in pH 7 Tris buffer. The detection limit of 1.0 x 10⁻⁵ mol dm⁻³ for cysteine and 2.24 x 10⁻⁷ mol dm⁻³ for histidine were obtained. Cyanide can be detected down to 1 x 10⁻¹¹ mol dm⁻³ using [CoTm-3,4-tppa]⁴⁺-GCE in pH 10.8 buffer. Cyanide and S0₂ coordinate to the [CoTSPc]⁴⁻ species. The coordination is accompanied by oxidation of the central Co(II) metal, forming a [Co¹¹¹CoTSPc]³⁻ species. The rate constants for cyanide coordination to the [Co¹¹TSPc]⁴⁻ complex are larger than those reported for the coordination of cyanide to FePc and RuPc complexes in non-aqueous media. Autoreduction of [Co¹¹Tmtppa]⁴⁺ occurred in the presence of either histidine or cysteine, with the formation of metal reduced species, [Co¹Tmtppa(-2)]³⁺. Nitric oxide and nitrite coordinate to the [Co¹¹Tmtppa]⁴⁺ species, without auto-reduction of this species, which was observed for cysteine or histidine. The use of [Co¹¹TSPc]⁴ resulted in improved rate of interaction with nitrite when compared to the [Co¹¹Tmtppa]⁴⁺ species.
  • Full Text:
  • Date Issued: 2003
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