Microbiological evaluation of the Mhlathuze River, KwaZulu-Natal (RSA)

Continuous faecal pollution in source water is a global problem that is particularly debilitating to rural communities that are directly dependent on untreated source water for all their domestic and other purposes. The elevation of indicator bacteria levels (such as the faecal coliforms) in the water may pose a public health risk. This study reports the results of microbial monitoring of the Mhlathuze River over a 21-month period. Elevated levels of indicator micro-organisms (both faecal and total coliforms) and heterotrophic plate count bacteria were observed from March 1998 to November 1999. Surface water temperature and rainfall during this period appeared to be some of the factors affecting the increased bacterial counts. Bacteria isolated from the river included E. coli, Pseudomonas spp., Enterobacter spp. (detected frequently), Serratia spp., Klebsiella spp., and Aeromonas hydrophila (detected less frequently). This study generated some essential baseline information of the microbial population for a section of the river utilised for domestic, agricultural and industrial purposes. WaterSA Vol.28(3) 2002: 281-28

Addressing emerging risks in transborder cloud computing and the protection of personal information : the role of internal auditors

There is general consensus amongst researchers that most South African companies are not yet ready to comply with the Protection of Personal Information Act No. 4 of 2013 (the POPI Act) as they lack the necessary skills, knowledge and understanding to effect such compliance. Whilst the flow of personal information to trans border clouds is lawful according to section 72 of the POPI Act, and cloud services offer benefits such as cost savings and agility, it has been determined that companies are yet to take cognisance of the fact that there are risks associated with such transfers. Five preeminent emerging risks associated with cloud data storage include data location, security, privacy, legal compliance and the cloud service providers themselves. Because of their role as assurance providers, with knowledge about organisational strategy, processes and operations, internal auditors are found to be uniquely positioned within companies to assist effectively with risk management as required by The Institute of Internal Auditors’ International Standards for the Professional Practice of Internal Auditing and the corporate governance standards presented in King III. Internal auditors have been shown to be able to assist in mitigating each of the five emerging risks through their effective auditing of contracts, policies, procedures and controls, which ultimately results in effective advice and assurance for boards, management and stakeholders.http://reference.sabinet.co.za/sa_epublication/sajaaram201

Micromechanical homogenization of a hydrogel-filled electrospun scaffold for tissue-engineered epicardial patching of the infarcted heart: a feasibility study

For tissue engineering applications, accurate prediction of the effective mechanical properties of tissue scaffolds is critical. Open and closed cell modelling, mean-field homogenization theory, and finite element (FE) methods are theories and techniques currently used in conventional homogenization methods to estimate the equivalent mechanical properties of tissue-engineering scaffolds. This study aimed at developing a formulation to link the microscopic structure and macroscopic mechanics of a fibrous electrospun scaffold filled with a hydrogel for use as an epicardial patch for local support of the infarcted heart. The macroscopic elastic modulus of the scaffold was predicted to be 0.287 MPa with the FE method and 0.290 MPa with the closed-cell model for the realistic fibre structure of the scaffold, and 0.108 MPa and 0.540 MPa with mean-field homogenization for randomly oriented and completely aligned fibres. The homogenized constitutive description of the scaffold was implemented for an epicardial patch in a FE model of a human cardiac left ventricle to assess the effects of patching on myocardial mechanics and ventricular function in the presence of an infarct. Epicardial patching was predicted to reduce maximum myocardial stress in the infarcted LV from 19 kPa (no patch) to 9.5 kPa (patch) and to marginally improve the ventricular ejection fraction from 40% (no patch) to 43% (patch). This study demonstrates the feasibility of homogenization techniques to represent complex multiscale structural features in a simplified but meaningful and effective manner

The time to extinction for an SIS-household-epidemic model

We analyse a stochastic SIS epidemic amongst a finite population partitioned into households. Since the population is finite, the epidemic will eventually go extinct, i.e., have no more infectives in the population. We study the effects of population size and within household transmission upon the time to extinction. This is done through two approximations. The first approximation is suitable for all levels of within household transmission and is based upon an Ornstein-Uhlenbeck process approximation for the diseases fluctuations about an endemic level relying on a large population. The second approximation is suitable for high levels of within household transmission and approximates the number of infectious households by a simple homogeneously mixing SIS model with the households replaced by individuals. The analysis, supported by a simulation study, shows that the mean time to extinction is minimized by moderate levels of within household transmission

Evaluation of Selected Aspects of the Nutrition Therapeutic Programme Offered to HIV-Positive Women of Child-Bearing Age in Western Cape Province, South Africa

Background: The Nutrition Therapeutic Programme (NTP) involves the provision of food supplements at primary health clinics (PHCs) to correct nutritional deficiencies in vulnerable groups. Although previous studies have identified problems with implementing the programme at PHCs, assessments of its efficiency have been scarce.Objective: To evaluate implementation of the NTP at PHCs that provide antiretroviral therapy.Methods: A cross-sectional, descriptive study was conducted at 17 PHCs located within 3 districts of Western Cape Province. Two target groups were chosen: 32 staff members working at the sites and 21 women of child-bearing age enrolled in the NTP. Questionnaires were used to obtain data.Results: Only 2 women (10%) lived in food-secure households; the rest were either at risk of hunger (29%) or classified as hungry (61%). Most of the women knew they had to take the supplements to improve their nutritional status, but the majority only recalled receiving basic nutritional advice, and the information was mainly given verbally. Ten of the women had shared their supplements with others, mostly with their children. The study identified lack of clearly defined NTP responsibilities at the PHCs, causing confusion amongst the staff. Although many staff members expressed problems with the NTP, only 38% of them reported having routine evaluations regarding the programme.Conclusion: Several aspects compromised the effectiveness of the NTP, including socioeconomic factors leading to clients’ non-compliance. The strategic organisation and implementation of the NTP varied between different PHCs offering antiretroviral therapy, and staff experienced difficulties with the logistics of the programme

A Preliminary Computational Investigation Into the Flow of PEG in Rat Myocardial Tissue for Regenerative Therapy

Myocardial infarction (MI), a type of cardiovascular disease, affects a significant proportion of people around the world. Traditionally, non-communicable chronic diseases were largely associated with aging populations in higher income countries. It is now evident that low- to middle-income countries are also affected and in these settings, younger individuals are at high risk. Currently, interventions for MI prolong the time to heart failure. Regenerative medicine and stem cell therapy have the potential to mitigate the effects of MI and to significantly improve the quality of life for patients. The main drawback with these therapies is that many of the injected cells are lost due to the vigorous motion of the heart. Great effort has been directed toward the development of scaffolds which can be injected alongside stem cells, in an attempt to improve retention and cell engraftment. In some cases, the scaffold alone has been seen to improve heart function. This study focuses on a synthetic polyethylene glycol (PEG) based hydrogel which is injected into the heart to improve left ventricular function following MI. Many studies in literature characterize PEG as a Newtonian fluid within a specified shear rate range, on the macroscale. The aim of the study is to characterize the flow of a 20 kDa PEG on the microscale, where the behavior is likely to deviate from macroscale flow patterns. Micro particle image velocimetry (μPIV) is used to observe flow behavior in microchannels, representing the gaps in myocardial tissue. The fluid exhibits non-Newtonian, shear-thinning behavior at this scale. Idealized two-dimensional computational fluid dynamics (CFD) models of PEG flow in microchannels are then developed and validated using the μPIV study. The validated computational model is applied to a realistic, microscopy-derived myocardial tissue model. From the realistic tissue reconstruction, it is evident that the myocardial flow region plays an important role in the distribution of PEG, and therefore, in the retention of material

An evaluation of the diagnostic adequacy and immunocytochemistry of manual liquid-based smears in breast aspirates

CITATION: Shibemba, A. L. et al. 2013. An evaluation of the diagnostic adequacy and immunocytochemistry of manual liquid-based smears in breast aspirates. Southern African Journal of Epidemiology and Infection, 28(2):117-121.The original publication is available at http://www.sajei.co.zaThe aim of this study was to determine if the Syner-Med®/Cell-Solutions® liquid-based cytology (LBC) technique would provide adequate diagnostic material when applied to breast fine-needle aspiration biopsy (FNAB) specimens and to determine its suitability for immunocytochemistry. A prospective study was undertaken of 38 consecutive patients who underwent FNAB of breast masses in the Fine Needle Aspiration Clinic at Tygerberg Hospital, Cape Town, over a period of six months. Conventional smear cytology slides (CSC) were formulated and the material that remained in the needle was used to prepare the LBC Syner-Med®/Cell-Solutions® slides. The CSC and LBC slides were evaluated by two pathologists. The assessed parameters were cellularity, background and representative diagnostic material. Immunocytochemical stains for pancytokeratin (MNF-116) and oestrogen receptor were performed in each case. In 33 cases (87%), LBC compared favourably with CSC. Adequacy rates of 84.2% for CSC and 76.3% for LBC were found. A diagnosis was made in 78.9% of the CSC cases and in 71% of the LBC cases. The LBC slides showed excellent results, with immunocytochemical staining for MNF-116 and oestrogen receptor. The Syner-Med®/Cell-Solutions® LBC fixative and preparation method provides an alternative technique for obtaining well fixed and prepared slides that are suitable for diagnostic cytology and immunocytochemistry.http://www.sajei.co.za/index.php/SAJEI/article/view/461Publisher's versio

Customer Specific Transaction Risk Management in eCommerce

Increasing potential for turnover in e-commerce is inextricably linked with an increase in risk. Online retailers (e-tailers), aiming for a company-wide value orientation should manage this risk. However, current approaches to risk management either use average retail prices elevated by an overall risk premium or restrict the payment methods offered to customers. Thus, they neglect customer-specific value and risk attributes and leave turnover potentials unconsidered. To close this gap, an innovative valuation model is proposed in this contribution that integrates customer-specific risk and potential turnover. The approach presented evaluates different payment methods using their risk-turnover characteristic, provides a risk-adjusted decision basis for selecting payment methods and allows e-tailers to derive automated risk management decisions per customer and transaction without reducing turnover potential

Numerical Study of a Field Theory for Directed Percolation

A numerical method is devised for study of stochastic partial differential equations describing directed percolation, the contact process, and other models with a continuous transition to an absorbing state. Owing to the heightened sensitivity to fluctuationsattending multiplicative noise in the vicinity of an absorbing state, a useful method requires discretization of the field variable as well as of space and time. When applied to the field theory for directed percolation in 1+1 dimensions, the method yields critical exponents which compare well against accepted values.Comment: 18 pages, LaTeX, 6 figures available upon request LC-CM-94-00