84 research outputs found
Behaviour planning and problem solving deficiencies in children with symptoms of attention deficit hyperactivity disorder from the Balobedu culture, Limpopo province, South Africa
No full textObjective: To compare planning behaviour (frontal lobe functioning) in children with and without symptoms of attention deficit hyperactivity disorder (ADHD). Method: A total of 90 children (45 with symptoms of ADHD and 45 matched controls without ADHD symptoms) of both genders, who were medication naïve, from the Balobedu culture (Limpopo province, South Africa), aged 7–13 years, participated in the study. The performance of the two groups was compared on a test of planning and problem solving, the Tower of London (ToL) task. The results were analysed as a function of gender and ADHD subtype. The Finger Tapping test (testing fine motor skills) was used as a control test to verify that the expected differences were not due to poor motor skills. Results: The children with ADHD symptoms scored significantly lower than the non-ADHD comparison group which indicated deficiency in frontal lobe functioning (p = 0.00). The difference in performance was not due to poor motor control (p = 0.70).
Conclusion: Children with ADHD symptoms show deficits in behavioural planning which indicates impairment of functions of the frontal areas supplied by the mesocortical dopamine branch. More so than others, the ADHD Inattentive and Combined subtypes showed poor performance in the Tower of London task, indicating poor organisational and planning skills in these groups. The results also did show that the difference was not due to problems with motor control and that the ToL task is a culture-fair instrument for testing planning behaviour
Pre legislative and legislative scrutiny processes: the contribution of Parliament to quality legislation
No full textIn this LLM dissertation the author argues that deficiencies in the pre-legislative and legislative scrutiny processes harbours bad quality legislation. The author makes an analysis of the pre-legislative and legislative process in Botswana to highlight the deficiencies which may harbour bad quality legislation and uses the Report of the Select Committee on the Modernisation of the House of Commons of 1997 as criteria of how pre-legislative scrutiny can benefit and enhance quality of legislation and assesses the system in Botswana against the said criteria. To this end the dissertation relies on the views of the authors who have studied the process in the United Kingdom looking at bills that had undergone the process to establish the effect of the process on quality of those bills. They are therefore used as lessons for Botswana. The dissertation also relies on other relevant literature and materials on the subject matter
Chronic inflammatory lung disease in human immunodeficiency virus (HIV)-infected children. Epidemiological considerations, aetiological determinants and the efficacy of low dose erythromycin in bronchiectasis
No full textThesis (PhD)--University of Pretoria, 2012.Human immunodeficiency virus (HIV) infection has reached epidemic proportions in South Africa. The availability of highly active anti-retroviral therapy (HAART) prolongs life in HIV-infected persons, who may subsequently present with chronic manifestations of HIV-infection. The respiratory morbidity attendant to HIV-infection, even in the presence of HAART is high, the aftermath of which is lung tissue destruction and bronchiectasis. As a consequence of the political decision not to offer HAART to HIV-infected children, a number of children in South Africa have been left with severe consequences of uncontrolled HIV-infection. Bronchiectasis is one of those and because children with this devastating condition were numerous in the Pretoria region, the author and her colleagues began a Chronic Lung Disease Clinic in that region. This prompted the idea of investigating both the epidemiological profiles of these children and an attempt to intervene with both standard bronchiectasis guideline care and the use of a form of therapy commonly employed in other forms of bronchiectasis. This thesis explores those ideas. Important new and novel findings that were consequent were; that bronchiectasis is diagnosed late in HIV-infected children at a mean age of 6.9 years. The predominant organisms cultured from the airways are Haemophilus influenzae and parainfluenzae in 49% of samples. Pseudomonas aeruginosa (PA), common in cystic fibrosis (CF)-bronchiectasis is an uncommon pathogen in HIV-related bronchiectasis; isolated in only 2% of specimens. Tuberculosis (TB), at least as reported, is a significant antecedent of bronchiectasis, reported in 48.5%of children. A further 21.2% of the patients had received more than two courses of anti-TB treatment. However, proof of TB infection has been lacking. Respiratory morbidity is significant with the mean forced expiratory flow in one second (FEV1) of 53%, in this cohort at the time of presentation. Thirty-six percent of all children were exposed to environmental tobacco smoke, although this was not correlated with disease severity or HIVdisease progression. There is elevation of immunoglobulins in HIV-related bronchiectasis, with a mean IgE of 79 kU/l. This was not, though, associated with HIV disease progression as previously described in adult studies, nor with the presence of allergic bronchopulmonary aspergillosis (ABPA). The elevation in IgE was also not associated with an elevation of T helper-2 mediated cytokines, confirming the lack of association with atopy. The predominant cytokine, identified is interleukin (IL)-8, both systemically and locally (in airway secretions). There was elevation of other T helper-1 driven cytokines, reflecting an ability to mediate adequate inflammatory responses, which was independent of the level of immunosuppression. With the presence of HAART, there was a decline in the pro-inflammatory cytokines over time, which may be attributed to the ongoing effect of HAART that ties in to, or goes beyond the restoration of T cell numbers. Soluble triggering receptor expressed on myeloid cells (sTREM), an innate immune marker, is elevated in children with HIV-related bronchiectasis when compared to a control group of children with cystic fibrosis-related bronchiectasis. sTREM is not associated with the presence of exacerbations and the level of immunosuppression. The use of an anti-inflammatory drug erythromycin also did not impact the sTREM values. There was also no relationship between sTREM and pro and antiinflammatory cytokines and chemokines. Fluorine-18-fluorodeoxyglucose positron emission tomography (18F-FDG PET) could not reliably predict the presence of pulmonary exacerbations. Its diagnostic value was limited to identifying disease activity in acute pneumonia. 18F-FDG PET also had no significant correlation with CRP, inflammatory cytokines or markers of HIV disease activity. In a randomised controlled trial of erythromycin, a cost-effective immunomodulatory drug, compared to placebo, erythromycin was ineffective in reducing the number of pulmonary exacerbations. Erythromycin also failed to demonstrate any effect on systemic and local pro- and anti-inflammatory cytokines/chemokines. With access to anti-retroviral therapy, airway clearance, nutritional rehabilitation and vigilant follow up there was an improvement in pulmonary function parameters and stability of the degree of bronchiectasis that we propose is probably in keeping with an organ system disease modifying effect that may be, an as yet, undefined and undescribed byproduct of HAART.Paediatrics and Child Healthunrestricte
Evaluation of letsoku and related Southern African indigenous clayey soils
No full textThesis (PhD)--University of Pretoria, 2017.The nature of letsoku and related clayey soils, traditionally used by indigenous Southern
African communities for a wide range of purposes, was explored. Thirty-nine samples were
collected from Botswana, Lesotho, Swaziland, South Africa and Zimbabwe. They were
analysed to determine their composition and physical properties. Structured interviews were
used to establish the purpose of use and the location of sourcing sites. The samples were in the
form of either powder or rocks, and some were supplied as dry rolled clay balls. Cosmetic
applications were almost universally indicated. However, other functions, related to artwork,
medicinal use, cultural symbolism and traditional beliefs, were also mentioned. The samples
covered a wide range of colours from bright red to yellow, but also from off-white to black,
with some having a light grey colour. It was therefore not surprising that the mineral
composition of the letsoku samples also varied widely. A black sample, and the yellow and
reddish pastel-coloured samples, contained significant quantities of the corresponding, colourimparting
iron oxides. Clay minerals featured prominently, although kaolinite and muscovite
were more often encountered as the dominant minerals than smectites. All the samples
contained silica and in some instances the content exceeded 90 % m/m SiO2. The presence of
high contents (more than 40 % m/m) of gibbsite in the samples from Venda represents a new
finding for clayey soils in traditional usage.Chemical EngineeringPhDUnrestricte
Theoretical studies of graphene and graphene-related materials involving carbon and silicon
No full textDissertation (MSc)--University of Pretoria, 2011.The structural and electronic properties of graphene and graphene-related materials have been intensively investigated using the plane wave based periodic density func- tional theory (DFT). The Vienna ab initio simulation package (VASP) code employing the generalized gradient approximation (GGA) for the exchange correlation potential was used. In all calculations, the geometry optimization option was employed in allow- ing the structure to fully relax. Hydrogen adatoms were adsorbed on C, Si and SiC in the graphene structure in-volving (1x1),(2x2),(3x3) and (4x4) two dimensional unit cells. The density of states reveals that the adsorption of 50% hydrogen makes the system metallic but 100% coverage at the on top sites generates a band gap. Our results show that SiC in the graphene structure is a plausible structure with a wide band gap. For adsoption of lithium adatoms, we considered various configurations involving the (1x1), (2x1) and (2x2) two-dimensional unit cells, and we consider the isolated Li dimer on graphene. We consider more detailed configurations than have been studied before, and our results compare favourably with previously calculated results where such results exist. For 100% coverage, we have new results for Li on the on-top site, which suggests a staggered configuration for the lowest energy structure for which the Li adatoms are alternately pushed into and pulled out of the graphene layer. For 50% coverage, Li favours the hollow site. We discovered that a careful relaxation of the system also shows a staggered configuration, a result that has not been investigated before.Physicsunrestricte
The therapeutic value of Aloe Ferox Mill
No full textThesis (M. Tech. (Biomedical Technology)) -- Central University of Technology, 2014The rising costs of health care, the outbreak of drug resistant organisms, health
depleting lifestyles and the risky side effects of currently used drugs are world-wide
problems. This has led to the search for novel drugs and drug leads. Traditional
healers and other individuals across the globe possess unlimited knowledge on the
healing powers of different plants that has been passed on through generations. This
knowledge together with scientific investigations can lead to the eradication of most
of the diseases either by treatment or prevention.
Aloe ferox Mill. is one of the plants that have gained a lot of interest from the
pharmaceutical industry. The plant has over 80 documented medicinal uses. These
include treatment of impotence and infertility, sexually transmitted infections, arthritis,
hypertension, leukaemia, bacterial and fungal infections. It is also known as a blood
purifier, widely used as a laxative and anti- inflammatory agent. More research is
required to discover more about A. ferox and its benefits to health as well as to
investigate its potential for the development of novel drugs.
The current study was focused at investigating the anti- cancer, anti- microbial antidiabetic,
cytotoxic activities and phytochemical composition of leaf extracts of A.
ferox. Three cancer cell lines namely: breast (MCF7), colon (HCT116) and prostate
(PC3) cancer cell lines were used to investigate the anticancer activity of the extracts
using the Sulforhodamine B (SRB) method.
To determine the anti- diabetic activity of the plant extracts the C2C12 and Chang
cell in- vitro models of glucose uptake were used. The micro- dilution technique was
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used to evaluate the antibacterial and antifungal activity of the extract. The safety of
these extracts against normal human foetal lung fibroblasts (W138), Chang and
C2C12 cells was done by through the SRB and the MTT methods. To determine the
phytochemical profile of A. ferox the DPPH radical scavenging and the Folin
Ciocalteu methods were used to test the antioxidant activity and the total phenolic
content of the different extracts respectively. Different methods were used to
determine the presence of phytochemicals such as steroids, saponins, alkaloids,
carbohydrates and flavonoids. LCMS was also done to detect the elemental
composition of the plant extracts.
According to the CSIR criteria A. ferox was inactive against the cancer cell lines
used. It however exhibited antioxidant activity even at low concentrations, with an
EC50 of 0.865 ± 0.783. The methanol extract showed more phenolic content than
the dichloromethane and aqueous extracts at a concentration of 5mg/ml. It is
believed that the antioxidant activity correlates with the phenolic content and quality
of the phenols present in the plant and more assays have to be done to prove this
hypothesis. Other phytochemicals found in the extract included saponins, steroids,
alkaloids as well as flavonoids. Both the methanol and aqueous extracts of A. ferox
caused a significant increase in glucose uptake by C2C12 cells but caused a slightly
decreased uptake by the Chang cells. The plant extracts inhibited the growth of
Staphylococcus epidermidis, Streptococcus pneumonia, Escherichia coli and
Candida albicans at a concentration of 15mg/ml extract. Candida tropicalis and
Escherichia faecalis were resistant to A. ferox extracts. Finally the extracts showed
no toxic activity against the normal foetal lung fibroblasts, Chang and C2C12 cells
validating the safety of this plant for human use.
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The results in conjunction with literature findings show A. ferox to be a promising
source of drugs and therapeutic agents. Due to the fact that traditional healers
already rely on it as treatment for different ailments, it is important that the safety of
the plant for use has been validated though other studies and clinical trial still need
to be done to fully confirm this. All the information gathered also showed this plant to
be of great benefit against major health problems, responsible for millions of deaths
each year such as cancer, cardiovascular and inflammatory diseases, and diabetes.
There is however still a great need for more investigation to be done on this plant
against a vast majority of organisms and diseases so as to fully benefit from it
Research Mentorship
No full text“The lessons drawn on in this book are clear: do not wait to reach some place or position in life where you feel like you are prepared to give back or pour into people; you are already prepared and positioned on some level!” Prof Glenda Gray, President and CEO of the South African Medical Research Council
There are barely any research mentorship books despite many conversations on it within academia and the role it can potentially play in the development and retention of academics in the pipeline. Academic institutions, appear not to have any solid mentorship frameworks that can be used to guide academics in the provision of robust research mentorship programmes. This original book details how research mentorship helped the author, a black woman in a predominately male-dominated patriarchal environment and the 33 mentees whose expressions have been captured in the book, to reach the pinnacle of academia despite a severe shortage of African women who have ascended to leadership roles within academia. The book showcases the value of research mentorship in developing leadership and support to the next generation of academics as well as deduce lessons learnt that can help to carry the knowledge enterprise forward. Further, it illustrates how research mentorship aided African women researchers in navigating non-diverse environments, early career struggles, post-graduate studies, work-life challenges as well complexities of scientific productivity, professional visibility, scientific connectivity (networks and collaborations), and resource mobilization, among others. The book offers potential mentors and mentees context-specific guidelines for effective mentorship, and best practices to enable scale-up. It also demonstrates how mentorship can contribute towards inclusivity and diversity and thus aid in narrowing persistent disparities in research, science, and academia
The regulation of insolvency practitioners in South African insolvency law
No full textAbstract: The law of insolvency has become a dynamic part of the law and it ought to be subject to continual changes to adjust to arising challenges and new circumstances.1 The aim of the insolvency system has always been to ensure creditors receive an equitable share of the insolvent estate and thus regarded as a mere system of execution. The latter notion has rather been regarded as simplistic. 2 Effective and efficient insolvency systems are essential components to the country’s financial systems and serve as a backbone for the success or failure of the system.3 When the World Health Organisation (WHO) declared Covid-19 to be a global pandemic on the 11th of March 2020, the aftermath has become an unprecedented event in modern world history.4 The world economy is in disarray and the South African economy has not been spared the devastating after-effects of the global pandemic. This has consequently led to several countries embarking on a trajectory of re-evaluating their insolvency law legislation and policies to countenance the effects of the global pandemic on the economy.5 Amidst the unanticipated challenges, the importance of having in place effective regulations in the insolvency system could have never been more accentuated...LL.M. (Commercial Law
Challenges and opportunities for survival entrepreneurs in the township of Soweto
No full textA research report submitted in partial fulfillment of the requirements for the degree of Master of Business Administration to the Faculty of Commerce, Law, and Management, Wits Business School, University of the Witwatersrand, Johannesburg, 2024This research paper investigated the challenges and opportunities of survivalist entrepreneurs in Soweto by evaluating the effectiveness of the entrepreneurial ecosystem. The study also examined the potential of using education to improve the entrepreneurial mindset. Additionally, the research investigated how education and the entrepreneurial mindset can be leveraged to improve business performance. A positivist paradigm was adopted to guide the quantitative research strategy. A cross-sectional study was conducted, and the data was collected from 125 respondents through a self- administered questionnaire. The population sample was subdivided into smaller groups based on the participant’s geographical location within Soweto, this was done through cluster sampling. Thereafter, the convenience sampling technique based on availability and accessibility was employed to reach the participants within the designated clusters. The hypotheses were evaluated through a single moderated regression model as the conceptual framework perfectly represented a moderated mediation model. The results from the model summary confirmed that all three variables – entrepreneurial mindset, entrepreneurial education, and entrepreneurial ecosystem – significantly influenced business performance. The direct effects of the entrepreneurial ecosystem on the entrepreneurial mindset were confirmed to be significant. Furthermore, the research demonstrated that the entrepreneurial mindset mediated the relationship between the entrepreneurial ecosystem and business performance in the township of Soweto. The practical implications of the study are that further investment in developing the resources and strengthening the support infrastructure in the township of Soweto will create more opportunities for survivalist entrepreneurs to improve their business performance. The study revealed that those with increased education levels are not immune from the systemic challenges that may cause individuals to start informal businesses in the township. Therefore, creating educational programmes that focus on developing practical skills could have a positive effect, empowering these survivalist entrepreneurs with the necessary skills to improve their business performance.MM202
Propagation and ex situ conservation of protea roupelliae subspecies hamiltonii
No full textA dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfillment of the requirements for the degree Master of Science
2019With nearly 10% of the world’s flora in South Africa and approximately 30 000 species of higher plants, Protea roupelliae subsp. hamiltonii is one of the 15.5% of species in South Africa threatened with extinction. This is attributed to its reduced seed production and amplified by its slow growth. The aim was to study the germination and ex situ conservation of this subspecies to contribute to improving its long-term conservation. The objectives concerning germination were: (a) to understand the germination and viability of the canopy-stored seeds (serotiny) in relation to their age on the plant, (b) to establish the relationship between the size of the plant canopy and the number of infructescences produced per plant, (c) to investigate if there is a relationship between seed predation (granivory) and seed age, and (d) to observe the number of viable (mass range of 0.017 g to 0.029 g) seeds produced per seed age class (1-3 ‘years’ of age).
Ex-situ conservation aspects studied were (e) the effect of seed pre-storage water content variation on post storage behaviour and germination, and (f) optimising in vitro propagation methods for this subspecies using six different types of media with, varying strengths of nutrients, and different types of growth regulators.
Protea roupelliae subsp. hamiltonii cones were collected and recorded according to their ages. The plant canopy and volume of the plants were measured and recorded. The number of cones produced were very poorly correlated with plant canopy area (r2=0.0963). The seeds were then removed from the cones, counted and weighed before being categorised by cone age and seed mass. The mean number of seeds per cone was 104.62, 107.67 and 100.00 for the three seed ages respectively with viable seeds (mass range of 0.017 g to 0.029 g) of 3199 for year three seeds which was not significantly different to year one seeds at a seed count of 3062. The two-year-old seed count of 2525 was significantly less than both one and three-year-old seeds. The 1-year old seeds of Protea roupelliae subsp. hamiltonii had a higher germination percentage of 86%, compared with the 2- and 3-year-old seeds, which both had a 56% germination. The granivory of the seeds affects the germination of seeds due to the damage caused to the seed embryo. Granivory was more prevalent in three-year-old seeds at 8.56%, followed by one-year old seeds with 4.81%, and the least being 2.58% for two-year-old seeds. Thirty-eight plants were sampled with a yield of 221 cones; 69 were 1-year old, 64 were 2-year old and 88 were 3-year old cones. The total number of seeds produced per age group was 7219 (1-year old cones), 6891 (2-year old cones) and 8800 (3-year old cones).
The seeds were shed at water contents varying from 0.0471-0.0938 g.g-1 d.m.b. The water content extremes resulted in a variation of results yielding uncertain protocols regarding seed storage at low temperatures (ambient-70oC). In an attempt to find optimum water contents for low temperature (oC) storage, seeds were equilibrated to 50% relative humidity (RH) prior to storage and the coefficient of variation of seed water content decreased from 19.58% to 13.20% for all the seeds combined. Seeds were stored for 6 and 12 months at different temperatures; -70oC, -20oC, 4oC, 25oC and a control of no storage treatment. Seeds stored for 6 months showed higher variation in water content across all storage conditions/treatments than those stored for 12 months. Seeds stored at -70oC for 12 months showed less change in their water content resulting in less variation and a 60% germination, which was lower than that of the control seeds.
In vitro propagation methods using leaf and shoot axillary meristems were tested using two different media containing half (12⁄) strength and quarter (14⁄) strength Murashige and Skoog (MS) medium. Total contamination was observed on tissues disinfected using Sodium Hypochlorite and Tween-20® only, on both media. Leaf explants disinfected with the antioxidant solution and 0.1% Tween-20® method showed no contamination, but subsequently turned black and showed no development, while the shoot explants on the same decontamination regime became contaminated (100%) after 2 weeks. The use of the zygotic embryo for in vitro propagation via indirect somatic embryogenesis and organogenesis was assessed. Four media comprising of full and half (12⁄) strength Murashige and Skoog (MS) medium powder and exogenously added 0.5 mg. l-1 Picloram or 0.5 mg. l-1 2.4D were used. All the media were augmented with 3 g. l-1 Gelzan® and 30 g. l-1 sucrose to a pH of 5.6-5.8. No development was observed on explants cultured on the half and full-strength medium without plant growth regulators, but explants cultured on half strength medium with 0.5 mg. l-1 2.4D and 0.5 mg. l-1 Picloram showed callus growths with no further development.
Micropropagation of the Protea roupelliae subsp. hamiltonii plant using leaf and shoot meristems is a process that should be standardized to achieve the conservation aims regarding plant population diminishment in nature. Continued efforts in the conservation of Protea roupelliae subsp. hamiltonii are encouraged to increase seedling establishment, field re-introduction and eventually population growth. Efforts should be amassed to further test the effect of seed water content variation pre-storage, on the successful short and potentially long-term storage of the seeds. In vitro propagation of the Protea roupelliae subsp. hamiltonii plant
should be optimised, with more consideration on the decontamination method for this systemically contaminated plant species.MT 202
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