Marston A.,University of the Free State
Journal of Chromatography A | Year: 2011
Bioautography on thin-layer chromatographic (TLC) plates is a means of detecting the biological activity of a sample which has migrated on the plate with a suitable solvent. It only requires small amounts of sample and is ideal for the investigation of plant constituents, which often occur as complex mixtures. It can be used for the target-directed isolation of these constituents. In contrast to HPLC, many samples can be run at the same time on TLC. Organic solvents, which cause inactivation of enzymes or death of living organisms, can be completely removed before biological detection. Many bioassays are compatible with TLC. Antimicrobial, radical scavenging, antioxidant activities and enzyme inhibition feature among the tests that are employed. © 2010 Elsevier B.V.
Louw L.,University of the Free State
Journal of Laryngology and Otology | Year: 2010
Background: Since Virchow's first, 1855 publication on cholesteatoma, this disease has been the subject of extensive debate. The pathogenesis of acquired cholesteatoma is repeatedly explained on the premises of the migration, hyperplasia and metaplasia theories, but proof for the latter theory remains limited. In retrospect, there is progress toward better understanding of all the pathological mechanisms involved, as expounded in this review.Discussion: The triggers for cholesteatoma onset are diverse, and may involve tympanic membrane trauma (i.e. perforation, displacement, retraction or invagination), tympanic membrane disease, and/or tympanic cavity mucosa disease. Research has revealed that cell migration is replaced under inflammatory conditions by hyperplasia, which triggers the onset of cholesteatoma. Lately, the hyperplasia theory gained prominence and circumscription of the papillary cone formation concept provided insight into cholesteatoma progression (growth and expansion). Diseased mucosa can contribute to the development of retraction pockets and cholesteatoma. The type of cholesteatoma trigger and the role of chronic inflammation during disease progression and recurrence are important in guiding clinical intervention. Copyright © JLO (1984) Limited 2010.
Van Rensburg H.C.J.,University of the Free State
Human Resources for Health | Year: 2014
The purpose of this contribution is to analyse and explain the South African HRH case, its historical evolution, and post-apartheid reform initiatives aimed at addressing deficiencies and shortfalls. HRH in South Africa not only mirrors the nature and diversity of challenges globally, but also the strategies pursued by countries to address these challenges. Although South Africa has strongly developed health professions, large numbers of professional and mid-level workers, and also well-established training institutions, it is experiencing serious workforce shortages and access constraints. This results from the unequal distribution of health workers between the well-resourced private sector over the poorly-resourced public sector, as well as from distributional disparities between urban and rural areas. During colonial and apartheid times, disparities were aggravated by policies of racial segregation and exclusion, remnants of which are today still visible in health-professional backlogs, unequal provincial HRH distribution, and differential access to health services for specific race and class groups.Since 1994, South Africa's transition to democracy deeply transformed the health system, health professions and HRH establishments. The introduction of free-health policies, the district health system and the prioritisation of PHC ensured more equal distribution of the workforce, as well as greater access to services for deprived groups. However, the HIV/AIDS epidemic brought about huge demands for care and massive patient loads in the public-sector. The emigration of health professionals to developed countries and to the private sector also undermines the strength and effectiveness of the public health sector. For the poor, access to care thus remains constrained and in perpetual shortfall.The post-1994 government has introduced several HRH-specific strategies to recruit, distribute, motivate and retain health professionals to strengthen the public sector and to expand access and coverage. Of great significance among these is the NHI Plan that aims to bridge the structural divide and to redistribute material and human resources more equally. Its success largely hinges on HRH and the balanced deployment of the national workforce.Low- and middle-income countries have much to learn from South African HRH experiences. In turn, South Africa has much to learn from other countries, as this case study shows. © 2014 van Rensburg; licensee BioMed Central Ltd.
Francis D.A.,University of the Free State
Culture, Health and Sexuality | Year: 2012
This paper reports on research with 11 high school teachers in Durban and draws on positioning theory to raise important questions on the teaching of issues relating to homosexuality and bisexuality within sexuality education. Using data collected from classroom observations and in-depth interviews, it demonstrates that issues related to sexual diversity were in most cases ignored or avoided by teachers and when teachers did include aspects of homosexuality, they took up positions that endorsed the idea of 'compulsory heterosexuality'. I conclude by paying attention to ways we can deepen the teaching of homosexual and bisexual issues. © 2012 Copyright Taylor and Francis Group, LLC.
Grobbelaar J.U.,University of the Free State
Journal of Applied Phycology | Year: 2012
There is overwhelming evidence that microalgae would be the logical source of oils for biodiesel production, the best option for CO 2 sequestration and numerous other applications. However, this apparent lucrative approach is still in its infancy. In order to impact on global energy needs, bioremediation and other potential applications, vast quantities of biomass must be produced at a reliable rate and as cost-effective as possible. When extrapolating volumetric rates from laboratory or small-scale outdoor cultures to large-scale outdoor areal production rates, it becomes apparent that many of the potential claims are either misleading or still only a dream. Open raceway ponds are at present the only feasible culture system for the production of millions of tons of biomass. To date, at best photosynthetic efficiencies of around 1.2% have been achieved, but with present understanding and know-how efficiencies of double that should be achievable, especially when vertical mixing is increased in raceway ponds. © 2011 Springer Science+Business Media B.V.