Patient profi le of a tertiary obstetric-cardiac clinic

Background: Cardiac disease is the most important medical cause of maternal mortality in South Africa. Management of women with cardiac disease in pregnancy is highly specialised and they should ideally be evaluated early in pregnancy and in a multidisciplinary fashion with the aim of formulating a perinatal management plan. In order to facilitate the effi cient management of these patients in the context of a large tertiary hospital in South Africa a combined obstetric-cardiac (O-C) clinic was established at Tygerberg Academic Hospital (TBH) in 2010. Objective: The purpose of this review is to describe the patient profi le of an obstetric-cardiac clinic in South Africa, specifi cally the TBH O-C clinic and to share thelessons learnt from establishing this clinic. Methods: Retrospective review performed at TBH, a referral centre in the Western Cape Province of SouthAfrica. All women evaluated and/or managed at the Obstetric-Cardiac clinic between 10 August 2010 and 4 December 2012 were included. Results: There were 231 women, rheumatic heart disease (n=79; 34.2%) was the predominant cardiac disease followed by congenital heart disease (n=78; 33.8%), medical conditions (n=38; 16.4%) and previous peripartum cardiomyopathy (n=9; 3.9%). Eighty-two women (35.5%) were perceived to be extremely high risk and their entire pregnancies were managed in the Obstetric-Cardiac clinic. The most common RHD lesion was mitral regurgitation (34.2%) and mixed mitral valve disease (24.1%). The most frequent CHD was ventricular septal defects (n=27; 35%). Conclusions: The cardiac disease profi le of patients seen at this obstetric-cardiac clinic in a South African tertiary hospital refl ects a transition from the disease profi le of a typical developing country (high burden of rheumatic heart disease) to the disease profi le seen in a more developed country (high burden of congenital heart disease). This could indicate improved quality of socio-economic development and the health care system. The increasing complexity of cardiac pathology that has to be dealt with in pregnant patients presenting to a tertiary hospital requires close collaboration between the obstetrician, cardiologist, cardiac surgeon and anesthetist caring for these patients. A dedicated obstetric-cardiac clinic is a good model to utilise in a tertiary hospital when aiming to optimise the care of patients with cardiac disease in pregnancy

The Didascalies as sign-system in three dramas by M.S. Serudu

The dynamic nature of drama is reflected in the inherent dichotomous composition of text and performance. The continuing controversy about the infrequent public performances of the almost 250 published texts in African languages and the literary approach towards Northern Sotho texts have prompted the present survey. Two main reasons are identified for the existing textual centricity in the approach towards Northern Sotho dramas, namely text-external and text-internal factors. The latter forms the main focus of attention in this study. The role of the didascalies as semiotic sign-system - referring to all aspects of the dramatic text which contain instructions for a potential performance - are investigated. The scrutiny of the stage directions afforded an unequalled vantage point in revealing the ostensive or performance nature of the three dramas by M.S. Serudu. In conclusion possible solutions for the future are offered against the background of the findings arrived at in the analysis.African LanguagesM.A. (African Languages

MODELLING AND VALIDATION OF A TESTING TRAILER FOR ABS AND TYRE INTERACTION ON ROUGH TERRAIN

The main purpose of a vehicle anti-lock braking system (ABS) is to prevent the tyres from locking-up in order to brake efficiently whilst maintaining steering control and stability. Sport utility vehicles (SUV) are designed to drive on various roads under different driving conditions, making it challenging to identify optimal operating conditions for ABS algorithms to be implemented. This paper describes the development and modelling of a testing trailer that is designed to benefit the research of a SUV tyre operating in ABS braking modes on non-deformable rough terrain. The test trailer can be to investigate the variation of tyre contact forces and vibration characteristics influenced by ABS braking and rough terrain excitation. Undesirable fluctuations of wheel speed, normal force and braking moments make measurements more complicated and limits the performance of active safety systems. A trailer made from a Land Rover Defender chassis is used with standard ABS components and is implemented with a Bosch ABS algorithm for experimental tests. In addition to the ABS system the necessary measuring equipment such as Wheel Force Transducers (WFT), accelerometers, brake pressure transducers, GPS and vehicle speed measurement instrumentation is used. An Adams model of the trailer in co-simulation with ABS and test control in MATLAB/Simulink is created to validate the model. The centre of gravity position and inertia characteristics of the trailer are determined through experimental testing. A validated FTire tyre model, suitable for off-road conditions, is incorporated to accurately resemble the specific tyre used during tests. The validated Adams model and test trailer will enable further development of ABS algorithms including the identification of key parameters through which ABS braking can be optimised for various roads as well as optimizing interaction with semi-active suspension systems

Aflatoxin contamination of groundnuts in Mozambique

The incidence of fungal infection and levels of aflatoxin contamination (produced by Aspergillus flavus) were studied in groundnuts collected from farmers at lifting and after drying/curing, and from traders in Nampula, Mozambique, during 1997-98. Of 34 samples collected at lifting, 13 were contaminated with aflatoxins and 8 had aflatoxin levels >30 µg/kg. Of 30 samples collected after drying, 10 had aflatoxins and 4 had >30 µg/kg. Of 10 samples collected from traders, only 2 had aflatoxin contamination. Aflatoxin G1 was predominant in samples collected at lifting and aflatoxin B1 in samples collected from traders

A simulation study to compare reference and other priors in the case of a standard univariate Student t-distribution

In this paper, reference and probability-matching priors are derived for the univariate Student t-distribution. These priors generally lead to procedures with properties frequentists can relate to while still retaining Bayes validity. The priors are tested by performing simulation studies. The focus is on the relative mean squared error from the posterior median and on the frequentist coverage of the 95% credibility intervals for a sample of size n = 30. Average interval lengths of the credibility intervals as well as the modes of the interval lengths based on 2 000 simulations are also considered. The performance of the priors is also tested on real data, namely daily logarithmic returns of IBM stocks

Integrated management of groundnut rosette disease

An investigation was conducted to study the effects of cultural practices and host-plant resistance on rosette disease incidence and pod yields of elite groundnut genotypes during four growing seasons in Malawi. The effects of genotypes and cultural practices, and their interactions on rosette disease incidence were significant at pegging stage under high disease pressure in all seasons. The genotypic differences in disease incidence were spectacular under high disease infestation in all seasons. Resistant genotypes gave higher pod yields than susceptible genotypes under high disease incidence, irrespective of sowing time and plant population. However, pod yields were higher for early sown treatments at optimum plant population. There were no marked differences in pod yield between genotypes under low disease pressure. Overall, the combination of resistant genotypes with early sowing at optimum plant population exhibited the best performance under high disease infestation. Although the resistant genotypes gave the highest pod yields under high disease infestation, pod yields were consistently lower than the yields under low disease situation probably because of their susceptibility to groundnut rosette assistor virus (GRAV) component

Zero-order and prolonged release of atenolol from microporous FAU and BEA zeolites, and mesoporous MCM-41:Experimental and theoretical investigations

The potential of microporous zeolites FAU and BEA, and mesoporous MCM-41, for prolonged release of atenolol in drug delivery systems was investigated both experimentally, using drug release studies, and theoretically using classical molecular dynamics simulations. Remarkably, zero-order release of atenolol was achieved from FAU (SiO2:Al2O3 = 80:1) into phosphate buffer for 24 h followed by prolonged release for at least another 48 h. Experimental data also demonstrate the ability for all of the drug-zeolite combinations investigated to achieve prolonged release of atenolol, with the release rates determined by the combination of framework topology, aluminium content and drug release study media. Molecular dynamics simulations give an insight into the reasons for the different release rates observed for FAU and BEA. The results of this work emphasise the need for sophisticated models in order to explain subtle differences in release, such as those observed at different SiO2:Al2O3 ratios.</p

Progressive familial heart block type I : clinical and pathological observations

CITATION: 1991: .Van der Merwe, P.-L. et al. 1991. Progressive familial heart block type I : clinical and pathological observations. South African Medical Journal, 80:34-38.The original publication is available at http://www.samj.org.zaProgressive familial heart block type I (PFHB-I) is an autosomal inherited disease. It was previously postulated that the disease is limited to the cardiac conduction tissue. The presentation of a patient with dilated cardiomyopathy focused on the possibility that this might be part of PFHB-I. This observation led to routine echocardiographic examination of patients with complete heart block, who belonged to PFHB-I families, and another 5 cases with signs of dilated cardiomyopathy were identified. This is the first time, to our knowledge, that the histological picture of PFHB-I has been described. From these case reports it is clear that in the presence of a dilated cardiomyopathy the prognosis in PFHB-I tends to be poor.Publisher’s versio

Effects of common mutations in the SARS-CoV-2 Spike RBD and its ligand the human ACE2 receptor on binding affinity and kinetics

The interaction between the SARS-CoV-2 virus Spike protein receptor binding domain (RBD) and the ACE2 cell surface protein is required for viral infection of cells. Mutations in the RBD are present in SARS-CoV-2 variants of concern that have emerged independently worldwide. For example, the B.1.1.7 lineage has a mutation (N501Y) in its Spike RBD that enhances binding to ACE2. There are also ACE2 alleles in humans with mutations in the RBD binding site. Here we perform a detailed affinity and kinetics analysis of the effect of five common RBD mutations (K417N, K417T, N501Y, E484K, and S477N) and two common ACE2 mutations (S19P and K26R) on the RBD/ACE2 interaction. We analysed the effects of individual RBD mutations and combinations found in new SARS-CoV-2 Alpha (B.1.1.7), Beta (B.1.351), and Gamma (P1) variants. Most of these mutations increased the affinity of the RBD/ACE2 interaction. The exceptions were mutations K417N/T, which decreased the affinity. Taken together with other studies, our results suggest that the N501Y and S477N mutations enhance transmission primarily by enhancing binding, the K417N/T mutations facilitate immune escape, and the E484K mutation enhances binding and immune escape