The accountability and professional security of the South African higher education lecturer

The widening of access to higher education (HE) for more students has been a strategic priority of the South African (SA) Department of Higher Education and Training (DHET) over the past decade.  Simultaneously, lecturers are increasingly held to account for providing quality teaching and delivering employable graduates. Yet their work environment is characterised by poor support, lack of recognition for teaching efforts, and absence of legal protection when failing to fulfil the undefined yet high accountability expectations in their teaching-related work. This article reports on an empirical study, grounded in an inductive qualitative methodology from an interpretive-phenomenological perspective, which aimed to develop understanding of how SA lecturers involved in undergraduate teaching at three SA universities perceive accountability and security within their labour environment.  From the analysis and interpretation of semi-structured and focus group interview data, seven meaningful themes were identified, associated with either lecturer accountability or security.  The findings offer not only a clear delineation of internal and external teaching-related accountability, but also a comprehensive definition of lecturer professional security

The effect of oxygen and paraquat on the 14C-glucose oxidation of rabbit alveolar macrophages and lung slices

CITATION: Rossouw, D. J. & Engelbrecht, F. M. 1979. The effect of oxygen and paraquat on the 14C-glucose oxidation of rabbit alveolar macrophages and lung slices. South African Medical Journal, 55:558-560.The original publication is available at http://www.samj.org.zaIn this study, we measured the effects of different concentrations of paraquat (0.01 mM and 1.0 mM) on the 1-14CO2 and 6-14CO2 production of rabbit lung slices and isolated alveolar macrophages, in 20% and 95% oxygen phases respectively. A 95% oxygen phase induced an increase in the 6-14C-glucose oxidation of control lung slices over a 3-hour period, while the increased activity of the pentose pathway over the first 2 hours started to decline during the third hour of incubation. Paraquat (1.0mM) in 20% oxygen caused a consistent increase in the 6-14CO2 production by lung slices, but in a 95% oxygen phase gradually inhibited the 6-14C-glucose oxidation over a period of 3 hours. The pentose phosphate pathway was highly significantly stimulated by 1.0 mM paraquat in 20% and 95% oxygen over 3 hours. When isolated alveolar macrophages (viability 95%) were incubated in a 20% and a 95% oxygen phase respectively, both the 6-14C-glucose oxidation rates were significantly inhibited by 1.0 mM paraquat after 1 hour. Our results confirmed the initial increase in glycolytic metabolism induced by paraquat, but also indicated that the 6-14CO2 production was significantly inhibited by paraquat when lung slices were incubated in a 95% oxygen phase. The fact that the glucose metabolism in alveolar macrophages is more sensitive to paraquat exposure than that of cells in lung slices may be related to the genesis of the intra-alveolar pulmonary lesions described in the literature.Publisher’s versio

The effect of paraquat on the aerobic metabolism of rabbit alveolar macrophages and lung fibroblasts

CITATION: Rossouw, D. J. & Engelbrecht, F. M. 1979. The effect of paraquat on the aerobic metabolism of rabbit alveolar macrophages and lung fibroblasts. South African Medical Journal, 55:20-23.The original publication is available at http://www.samj.org.zaIn this study the effects of paraquat on the aerobic metabolism and viability of isolated rabbit alveolar macrophages and lung fibroblasts were investigated, and compared with the effects of other known metabolic inhibitors, i.e. sodium fluoride (NaF) and potassium cyanide (KCN). The manometrically and polarographically determined endogenous oxygen consumption of lavaged alveolar macrophages compared very well (180,9 ± 35,8 and 169,3 ± 26,8 nmol per 106 viable cells per hour respectively). Exogenous glucose (10 mM) and autologous serum (1:3 v/v) added to the medium had no significant effect on the basal respiration rate. The mean cell protein content, determined by the micro-Kjeldahl and Lowry techniques, amounted to 242,6 ± 37,6 μg/106 macrophages. Paraquat (2 mM), like NaF (20 mM) and KCN (5 mM), decreased the viability of the macrophages far less than it did the oxygen utilization of the viable cells, and resulted in an 80% inhibitin of oxygen uptake. In contrast, paraquat (1 mM) induced a marked stimulation (230%) of the cyanide-insensitive respiration of alveolar macrophages. The concentrations of paraquat (nmol/103 cells) which reduce macrophage metabolism to almost zero were virtually non-toxic to fibroblasts, as measured by their oxygen consumption.Publisher’s versio

Overview of HIV-related lipodystrophy

Lipodystrophy is a well-recognised adverse effect of HIV and antiretroviral therapy, with certain antiretrovirals, specifically thymidine analogues, implicated in the aetiology and pathogenesis. Lipodystrophy is often accompanied by metabolic complications, such as hyperlipidaemia and insulin resistance, which increase risk for cardiovascular disease. There are limited data on the effect of treatment modification, pharmacological interventions and surgical management on this condition.Here we summarise the latest data on lipodystrophy, with the aim of facilitating informed decision-making in managing this condition. In light of the absence of cost-effective measures to treat lipoatrophy and lipohypertrophy, prevention remains the best option; we recommend targeted annual screening. Healthcare workers should be sensitised to early detection in patients on thymidine-based regimens, and affected patients should be switched to an appropriate regimen as soon as feasible. There is no evidence to support the use of new-generation ARVs, except in patients with significant hypercholesterolaemia, where atazanavir and raltegravir may present better options.S Afr J HIV Med 2013;14(1):29-33. DOI:10.7196/SAJHIVMED.87

Linking gene regulation and the exo-metabolome: A comparative transcriptomics approach to identify genes that impact on the production of volatile aroma compounds in yeast

BACKGROUND: 'Omics' tools provide novel opportunities for system-wide analysis of complex cellular functions. Secondary metabolism is an example of a complex network of biochemical pathways, which, although well mapped from a biochemical point of view, is not well understood with regards to its physiological roles and genetic and biochemical regulation. Many of the metabolites produced by this network such as higher alcohols and esters are significant aroma impact compounds in fermentation products, and different yeast strains are known to produce highly divergent aroma profiles. Here, we investigated whether we can predict the impact of specific genes of known or unknown function on this metabolic network by combining whole transcriptome and partial exo-metabolome analysis. RESULTS: For this purpose, the gene expression levels of five different industrial wine yeast strains that produce divergent aroma profiles were established at three different time points of alcoholic fermentation in synthetic wine must. A matrix of gene expression data was generated and integrated with the concentrations of volatile aroma compounds measured at the same time points. This relatively unbiased approach to the study of volatile aroma compounds enabled us to identify candidate genes for aroma profile modification. Five of these genes, namely YMR210W, BAT1, AAD10, AAD14 and ACS1 were selected for overexpression in commercial wine yeast, VIN13. Analysis of the data show a statistically significant correlation between the changes in the exo-metabome of the overexpressing strains and the changes that were predicted based on the unbiased alignment of transcriptomic and exo-metabolomic data. CONCLUSION: The data suggest that a comparative transcriptomics and metabolomics approach can be used to identify the metabolic impacts of the expression of individual genes in complex systems, and the amenability of transcriptomic data to direct applications of biotechnological relevance

Feeding practices and nutritional status of HIV-exposed and HIV-unexposed infants in the Western Cape

Background: Optimal infant- and young child–feeding practices are crucial for nutritional status, growth, development, health and, ultimately, survival. Human breast milk is optimal nutrition for all infants. Complementary food introduced at the correct age is part of optimal feeding practices. In South Africa, widespread access to antiretrovirals and a programme to prevent mother-to-child transmission of HIV have reduced HIV infection in infants and increased the number of HIV-exposed uninfected (HEU) infants. However, little is known about the feeding practices and nutritional status of HEU and HIV-unexposed (HU) infants.Objective: To assess the feeding practices and nutritional status of HIV-exposed and HIV-unexposed (HU) infants in the Western Cape.Design: Prospective substudy on feeding practices nested in a pilot study  investigating the innate immune abnormalities in HEU infants compared to HU infants. The main study commenced at week 2 of life with the nutrition component added from 6 months. Information on children’s dietary intake was obtained at each visit from the caregiver, mainly the mother. Head circumference, weight and length were recorded at each visit. Data were obtained from 6-, 12- and 18-month visits. World Health Organization feeding practice indicators and nutrition indicators were utilised.Setting: Tygerberg Academic Hospital, Western Cape. Mothers were recruited from the postnatal wards.Subjects: Forty-seven mother–infant pairs, 25 HEU and 22 HU infants, participated in this nutritional substudy. Eight (17%) infants, one HU and seven HEU, were lost to follow-up over the next 12 months. The HEU children were mainly Xhosa (76%) and HU were mainly mixed race (77%).Results: The participants were from poor socio-economic backgrounds. In both groups, adherence to breastfeeding recommendations was low with suboptimal dietary diversity. We noted a high rate of sugar- and salt-containing snacks given from a young age. The HU group had poorer anthropometric and nutritional indicators not explained by nutritional factors alone. However, alcohol and tobacco use was much higher amongst the HU mothers.Conclusion: Adherence to breastfeeding recommendations was low. Ethnicity and cultural milieu may have influenced feeding choices and growth. Further research is needed to understand possible reasons for the poorer nutritional and anthropometric indicators in the HU group

The effects of an L-methionine combination supplement on symptoms of upper respiratory tract infections and performance in ultramarathon runners before, during and after ultra-endurance exercise

Objective. To evaluate whether supplementation with an L-methionine combination would reduce the incidence of upper respiratory tract symptoms (URTS) and improve performance in ultramarathon runners. Design. A double-blind placebo-controlled study. Setting. Twenty-one ultramarathon runners (17 males, 4 females) preparing for participation in an 87.3 km ultramarathon. Interventions. L-methionine combination supplement (L-methionine, vitamin B6, vitamin B12, folic acid and magnesium) or placebo containing potato starch. Main outcome measures. Incidence of URTS was recorded during the runner's preparation for an ultramarathon race (75 days) and recovery from the same (75 days). CD4+, CD8+ cell counts and ratios were measured pre race, immediately post race and 75 days post race. VO2max and endurance fitness (percentage VO2max at 4 mmol-1 lactate concentration) were measured during the preparation for the race. Results. During the preparation period the incidence of URTS was 36% in the supplement group and 80% in the placebo group (p = 0.08). The incidence of URTS during the 3 weeks post race was 27% in the supplement group and 40% in the placebo group (p = 0.65). The CD4+/CD8+ cell ratios were not significantly different between groups. Endurance fitness prior to the race and race times were not significantly different. Conclusions. Although the findings of the current study show that an L-methionine combination supplement did not reduce the incidence of URTS or improve performance in ultramarathon runners, benefits may be found with a more detailed investigation using larger sample sizes and immunosuppressed athletes. South African Journal of Sports Medicine Vol.16(1) 2004: 10-1

Blind source separation aided characterization of the γ′ strengthening phase in an advanced nickel-based superalloy by spectroscopic 4D electron microscopy

The γ’ strengthening phase in an advanced nickel-based superalloy, ATI 718Plus, was characterized using a blind source separation applied to a four dimensional X-ray microanalysis dataset obtained by scanning transmission electron microscopy. Selected patterns in the X-ray spectra identified by independent component analysis were found to be spatially and chemically representative of the matrix (γ) and precipitate phases (γ’) present in the superalloy, enabling their size, shape and distribution to be determined. The three dimensional chemical reconstruction of the microstructure may provide insight into the role of the various alloying elements in the evolution of the microstructure at the nano-scale.The research leading to these results has received funding from the European Union Seventh Framework Programme under Grant Agreement 312483 - ESTEEM2 (Integrated Infrastructure Initiative-I3), as well as from the European Research Council under the European Union's Seventh Framework Programme (FP/2007-2013)/ERC grant agreement 291522 - 3DIMAGE. D.R. acknowledges support from the Royal Society’s Newton International Fellowship scheme. RKL acknowledges a Junior Research Fellowship at Clare College. RK acknowledges financial support from Rolls-Royce, EPSRC and the BMWi under EP/H022309/1, EP/H500375/1 and grant number 20T0813. F.d.l.P. and C.D. acknowledge 26 funding from the ERC under grant no. 259619 PHOTO EM. Special thanks to Giorgio Divitini and Lech Staniewicz for preparation of the FIB needle specimen and to Stephen A Croxall for SEM/FIB imaging.This is the final version of the article. It first appeared from Elsevier via http://dx.doi.org/10.1016/j.actamat.2016.01.04

Variable contribution identification and visualization in multivariate statistical process monitoring

CITATION: Rossouw, R. F.; Coetzer, R. L. J. & Le Roux, N. J. 2020. Variable contribution identification and visualization in multivariate statistical process monitoring. Chemometrics and Intelligent Laboratory Systems, 198. doi:10.1016/j.chemolab.2019.103894The original publication is available at https://www.sciencedirect.com/journal/chemometrics-and-intelligent-laboratory-systemsMultivariate statistical process monitoring (MSPM) has received book-length treatments and wide spread application in industry. In MSPM, multivariate data analysis techniques such as principal component analysis (PCA) are commonly employed to project the (possibly many) process variables onto a lower dimensional space where they are jointly monitored given a historical or specified reference set that is within statistical control. In this paper, PCA and biplots are employed together in an innovative way to develop an efficient multivariate process monitoring methodology for variable contribution identification and visualization. The methodology is applied to a commercial coal gasification production facility with multiple parallel production processes. More specifically, it is shown how the methodology is used to specify the optimal principal component combinations and biplot axes for visualization and interpretation of process performance, and for the identification of the critical variables responsible for performance deviations, which yielded direct benefits for the commercial production facility.https://www.sciencedirect.com/science/article/pii/S0169743919305088?via%3DihubPublishers versio