This research is concerned specifically with the growth of two selected algae found surviving in chlorinated water in outdoor swimming pools. Unialgal cultures were used to determine the free chlorine residuals that these algae were able to tolerate.

This thesis deals with electrical conductivity in thin films. Classical and quantum size effects in conductivity are discussed including some experimental evidence of quantum size effects. The component conductivity along the applied electric field of a thin film in a transverse magnetic field is developed in a density matrix method.

The growth events which are responsible for the phototropic curvature of seedlings towards blue light were investigated by growth analysis of seedlings of Avena sativa L. Time-lapse video analysis of coleoptiles given equivalent unilateral or bilateral blue light stimuli showed that both the duration and fluence-rate of the light treatments affected the growth responses which were recorded. The results suggest that the growth responses in bilateral light occur simultaneously with the growth changes which cause phototropic curvature, although they do not appear to make any contribution to the magnitude of curvature. Seedlings were also subjected to continuous unilateral microbeam (1mm) irradiation of discrete zones, to investigate whether 'message' transmission occurs in phototropism. The growth changes which occur in response to this treatment were recorded over the whole length of a 20 mm seedling, but began at different times in different zones. It was concluded that there must be some kind of 'message' transmission following perception of a phototropic stimulus in Avena. The kinetics of the response showed that it was unlikely that transmission could be simply due to tissue light-piping from the position of the original light beam. Unilateral irradiation of a small zone at the base of a coleoptile resulted in negative curvature. This experiment provided some evidence for acropetal transmission of the phototropic signal. A study was also made on the effects of wounding on the growth of Avena seedlings. This led to a re-evaluation of the significance of the traumatropic response to unilateral wounding. The experiments showed that even a slight wound can have severe effects on the growth of a coleoptile. The results are discussed in relation to previous theories on the mechanism of traumatropic curvature.

in English This thesis is a review of substances contained in medicinal plants, the side effects and complications that they provoke. The adverse drug reactions are directly related to the constituents contained in each plant. Information for this work was taken from sources published from 1965 until 2013, especially from The Essential Guide To Herbal Safety and from the databases webmd.com and ncbi.nlm.nih.gov. It is discussed how the use of natural medicinal drugs affect vital organs in the human organism and in which cases their consumption is contraindicated. Central nervous, cardiovascular, urinary, gastrointestinal, endocrine, haemopoietic, respiratory, urinary systems are affected and allergic reactions are possible to occur as complications. Hypericum perforatum is typical for causing gastrointestinal irritations and Chamaemelum nobile and Achillea millefolium are found to cause dermatic complications. Finally, Piper methysticum may induce extreme sedation, since it has anxiolytic and antiepileptic properties. Keywords: side effects, contraindications, medicinal plants, uses, constituents.

Doctor of Philosophy / Department of Mechanical and Nuclear Engineering / Sameer I. Madanshetty / Cavitation is a long studied phenomenon, fascinating and varied. Observed cavitation thresholds vary, typically ranging from the vapor pressure of the liquid to several atmospheres. Recent studies in cavitation involving very clean liquids give rise to thresholds that surpass 100 atmospheres. Calibrating such high intensity, high frequency, focused acoustic fields presents a significant challenge. The present investigation describes how it is possible to exploit the second order acoustic effect of radiation pressure to seek reliable calibration of the high intensity acoustic fields. Experiments describe how to account for the attendant second order effect of acoustic streaming in the evaluation of the radiation force to accomplish meaningful calibration. Beyond the measurement of the second order quantities associated with cavitation, the work also presents a first investigation of a direct estimation of implosion energies of collapsing bubbles near well-characterized surfaces.

Master of Science / Department of Physics / Jeremy Schmit / In this work, we present a model for the kinetics of amyloid fibril aggregation. In the model we mapped the process of Hydrogen bond (H-bond) formation and breakage to a random-walk. we captured the effect of side chains using position dependent H-bonds free energies which allows us to calculated the residence time for different binding alignments with the fibril. The residence time can be compared to the diffusion-limited attachment rate to give net aggregation stability. This stability increases exponentially with increasing number of bonds or binding energy in homopolymer chains, however for chains with patterned sequences, the residence time shows strong effects of the binding alignment. Using the residence time for uniform structures combined with estimate of the diffusion rate, we modeled and simulated the kinetics of amyloid aggregation. Results of the simulations gives the bond energies and concentrations required for the onset of growth of aggregates.

No description available.

M.Tech. / In spite of the improvement in the delivery of anti-cancer treatments over the past decade, side effects from these treatments remain inevitable. A common, distressing side effect that all cancer patients experience is fatigue. However, cancer related fatigue (CRF) remains one that is under-reported and under-treated. CRF is a topic that has received very limited attention in the South African context. Regardless of the amount of literature available on CRF, many questions continue to go unanswered. CRF has been identified as a side effect that is associated with physical, mental and psychological elements. Consequently, it has the ability to cause a delay in treatment schedules, impinge on daily functioning and impact negatively on the quality of life (QoL) in the cancer patient. Effective management strategies for patients during and after radiation treatment are thus essential to improve QoL. The aim of the study was to investigate the general pattern of fatigue experienced by patients diagnosed with various types of cancers during a radical course of radiotherapy. For the purpose of this study fatigue was defined according to the National Comprehensive Cancer Network (NCCN) Practice Guidelines in Oncology (www.nccn.org): “a distressing persistent subjective sense of tiredness or exhaustion related to cancer or cancer treatment that is not proportional to recent activity and interferes with usual functioning” A cross-sectional, theory-generating study was conducted to explore and describe the prevalence of fatigue, factors that could influence fatigue scores, strategies being used to alleviate this side effect and the impact of fatigue on QoL. One hundred and eighty patients were asked to complete a self-developed questionnaire in three oncology centres in Gauteng, South Africa. The NCCN Clinical Practice Guidelines in Oncology were used as a framework to direct the study. The results of the study illustrate that fatigue scores increased as radiotherapy progressed. However, not all the variables explored in the study significantly impacted on fatigue scores. The study revealed, though, that all cancer patients do experience CRF irrespective of the diagnosis. Management of the causes of CRF is thus essential to improve QoL for cancer patients.

Depuis l’abolition de la monarchie absolue en 1932, le royaume a connu des situations politiques variées : les activités « contre-révolutionnaires » des royalistes ; l’arrivée au pouvoir des militaires ; l’émergence de nouvelles classes politiques ; les massacres de civils ; les compromis entre les militaires, les royalistes et les progressistes ; l’incertitude sur l’avenir du royaume et de la couronne... L’échec de la transition démocratique thaïlandaise est expliqué généralement par un argument convenu : l’immaturité de la société thaïlandaise ; la démocratie libérale de type occidental ne serait pas appropriée pour le pays, notamment pour des « pauvres ruraux ignorants » ; l’armée est le seul acteur capable d’encadrer le développement d’une démocratie. Pourtant, cette étude présente une explication alternative ; elle démontre que la vie politique du royaume est déterminée par trois axes du pouvoir : les élites traditionnelles, dont la monarchie, l’armée et la haute fonction publique ; c’est cette situation qui explique l’échec du progrès démocratique. Et le coup d’État est la méthode préférée pour protéger le statu quo ; quant à la constitution thaïlandaise est semblable à une « lettre morte » ou à un « instrument de la politique au quotidien » ; elle ne représente plus la norme suprême qui exprime l’idéologie politique du pays ; au contraire, elle est utilisée non seulement pour légitimer a posteriori un coup d’État, mais également pour défendre la domination politique des groupes dominants. Nous pouvons donc conclure que le coup d’État thaïlandais est déclenché par l’armée royale avec l’appui de la monarchie et son réseau de conseillers ; puis, il est justifié par le roi et le judiciaire, en assurant l’impunité de ses auteurs par les lois et la constitution. / Since the abolition of absolute monarchy in 1932, the kingdom has experienced the various political situations: the ‘counter-revolution’ of the royalists, the dictatorial regime, the emergence of the new middle classes, the massacres of civilians, the political compromise, the uncertainty about the future of the kingdom and the crown… The failure of a transition to democracy is usually explained by the usual arguments: the political immaturity of Thai society, the ‘Western-style liberal democracy’ would not be appropriate for the country especially for ‘the ignorant masses’, the army is the only actor, who capable to promote democracy. However, this study presents an alternative explanation. It demonstrates that the political life of the kingdom is determined by three axes of power: traditional elites, including the monarchy, the army and the senior civil servant. It is this situation that explains the failure of the democratic process. And the coup is the traditional method to protect their status quo. As for the constitution, it is similar to a ‘dead letter’ or an ‘instrument of everyday politics’. It isn’t represented as supreme norm that expresses the country’s political ideology. On the contrary, it is used not only to legitimize a coup, but also to defend the political domination of the traditional elites. We can conclude that the Thai coups are triggered by the royal army with the support of the monarchy. Then, justified by the king and the judiciary, and assuring the impunity by the laws and the constitutions.

MSc, Occupational Therapy, Faculty of Health Sciences, University of the Witwatersrand / Infants and toddlers living in residential care facilities are at risk of developmental delay. Environmental factors contributing to this risk are the temporal context (how children spend their time) and social context (how and when caregivers interact with children). This study compared time-use patterns of children living in residential care facilities where caregiver training had previously taken place versus those in facilities where caregiver training had not taken place using a non-experimental, cross-sectional static group comparison study design. Spot observations were used to estimate time-use patterns of infants and toddlers living in residential care in Johannesburg. Results show that caregiver training increased the quantity of time infants spent with their caregivers (temporal context) and the quality of time toddlers spent with their caregivers (social context). Thus caregiver training has the potential to improve the environment in residential care facilities and can be used as an intervention strategy by occupational therapists.