Reconstruction of an Extensive Midfacial Defect Using Additive Manufacturing Techniques

Published ArticleMalignant peripheral nerve sheath tumors are extremely rare tumors arising in peripheral nerves. Only 17 cases involving the trigeminal nerve have ever been reported. These tumors have a very poor prognosis and very high rates of recurrence and metastases. Their recommended treatment involves complete tumor resection followed by radiation. This can be problematic in the head and neck region. We present a clinical case involving a 33-year-old female patient presenting with a slow-growing, exophytic mass of the anterior maxilla. Incisional biopsy and subsequent histological examination revealed a diagnosis of a malignant peripheral nerve sheath tumor. Surgical resection involved a complete maxillectomy, rhinectomy, and resection of the upper lip and aspects of the left and right cheeks. Reconstruction of the subsequent defect incorporated the placement of four zygomatic oncology implants to aid in retention of a facial prosthesis. These implants, however, were subsequently lost; and an anatomical model of the hard tissues was manufactured via 3D printing. This model was used to design and manufacture a titanium frame (customized implant) for the patient. The frame was then fixated and secured intraoperative with 21 cortical screws. A maxillary denture and silicone facial prosthesis were also made to fit onto this frame. This is the first known case where additive manufacturing, via the use of rapid prototyping and 3D printing, was employed to manufacture a facial prosthesis

Optimal use of existing freeway management surveillance infrastructure on pedestrian bridges with computer vision techniques

South Africa as a developing country has to make the most out of the infrastructure that are available. Given the high level of crash involving pedestrians, it is critical that all means available are utilised to characterise pedestrian movements on the highway and pedestrian bridges. This paper will focus on using the existing camera infrastructure, but will extend its use to automatically detect and count pedestrians that use the pedestrian bridges. The pedestrian movement data can be used to aid with the evaluation of pedestrian safety campaigns, or to recognise trends in pedestrian movement. The paper presents the impact of various parameter changes to the state of the art technique used, as well as orientation suggestions for future installations. This is done to make optimal use of existing infrastructure, and provides an alternative to existing high-end systems. The methodology includes training a computer vision-based algorithm to recognise and count pedestrians for specific scenes, for example pedestrian bridges. The paper evaluates different suppression techniques to reduce false positives. The results show that 72% of pedestrians can be detected (a hit rate of 72%), with the camera facing a pedestrian bridge squarely from the side, so that silhouettes are clearly visible. High end products not using existing infrastructure typically have a hit rate of 70%-90%. The solution in this paper competes with high-end products, and can be expanded for infrastructure security applications, e.g. monitoring copper cables or monitoring of high risk areas.Paper presented at the 35th Annual Southern African Transport Conference 4-7 July 2016 "Transport ? a catalyst for socio-economic growth and development opportunities to improve quality of life", CSIR International Convention Centre, Pretoria, South Africa.The Minister of Transport, South AfricaTransportation Research Board of the US

Using tracking data and an electro-mobility simulator to establish the energy requirements of electric minibus taxis in Tshwane

Papers presented virtually at the 41st International Southern African Transport Conference on 10-13 July 2023.The minibus taxi (MBT) is the dominant form of public transport across Sub-Saharan Africa (SSA). With a growing global call for greener transport, MBTs are seen as a key sector of implementation. The electrification of MBTs entails many challenges, including limited electricity resources and the lack of understanding of MBTs’ operational behaviour. In this paper, we estimate the electricity demand for future electric MBTs in the City of Tshwane, South Africa. We use existing origin and destination mobility data, which originated from vehicle-based tracking, and a micro-mobility simulation tool with an embedded electric vehicle model, called EV-Fleet-Sim. This simulation tool uses various SUMO packages to simulate mobility and calculate energy expenditure. The mobility dataset consists of various stop locations from a MBT fleet’s daily operation. The simulator uses a routing model, a virtual map, and a virtual driver model to convert the origin and destination data to high-fidelity mobility traces. The results are used in the electro-kinetic model to estimate the vehicles’ energy needs, from which charging opportunities can be derived. To illustrate this process and outputs, eight exemplar taxis with different operational patterns are selected for analysis. The results show a minimum and maximum median daily energy usage of 56 kWh and 215 kWh respectively, based on the mean observed daily distances travelled of 94 km to 330 km. While the energy demand varies significantly according to trip length and type of operation of the sub-fleet of 8 vehicles, clear morning and afternoon peaks are identified, along with charging opportunities during midday and at night

Health and economic impact of HIV/AIDS on South African households: a cohort study

BACKGROUND: South African households are severely affected by human immunodeficiency virus / acquired immunodeficiency syndrome (HIV/AIDS) but health and economic impacts have not been quantified in controlled cohort studies. METHODS: We compared households with an HIV-infected member, and unaffected neighbouring households, in one rural and one urban area in Free State province, South Africa. Interviews were conducted with one key informant in each household, at baseline and six months later. We studied 1913 members of 404 households, with 94% and 96% follow up, respectively. Household and individual level analyses were done. RESULTS: Members of affected households, compared to members of unaffected households, were independently more likely to be continuously ill (adjusted odds ratio (OR) 2.1, 95% CI 1.3–3.4 at follow up), and to die (adjusted OR 3.4, 95% CI 1.0–11), mainly due to infectious diseases. Government clinics and hospitals were the main sources of health care. Affected households were poorer than unaffected households at baseline (relative income per person 0.61, 95% CI 0.49–0.76). Over six months expenditure and income decreased more rapidly in affected than in unaffected households (baseline-adjusted relative expenditure 0.86, 95% CI 0.75–0.99 and income 0.89, 95% CI 0.75–1.05). Baseline morbidity was independently associated with lower income and expenditure at baseline but not with changes over six months. CONCLUSIONS: HIV/AIDS affects the health and wealth of households as well as infected individuals, aggravating pre-existing poverty

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Multidimensional Poverty and Child Survival in India

Background: Though the concept of multidimensional poverty has been acknowledged cutting across the disciplines (among economists, public health professionals, development thinkers, social scientists, policy makers and international organizations) and included in the development agenda, its measurement and application are still limited. Objectives and Methodology: Using unit data from the National Family and Health Survey 3, India, this paper measures poverty in multidimensional space and examine the linkages of multidimensional poverty with child survival. The multidimensional poverty is measured in the dimension of knowledge, health and wealth and the child survival is measured with respect to infant mortality and under-five mortality. Descriptive statistics, principal component analyses and the life table methods are used in the analyses. Results: The estimates of multidimensional poverty are robust and the inter-state differentials are large. While infant mortality rate and under-five mortality rate are disproportionately higher among the abject poor compared to the nonpoor, there are no significant differences in child survival among educationally, economically and health poor at the national level. State pattern in child survival among the education, economical and health poor are mixed. Conclusion: Use of multidimensional poverty measures help to identify abject poor who are unlikely to come out of poverty trap. The child survival is significantly lower among abject poor compared to moderate poor and non-poor. We urge t

Who is accessing public-sector anti-retroviral treatment in the Free State, South Africa? An exploratory study of the first three years of programme implementation

<p>Abstract</p> <p>Background</p> <p>Although South Africa has the largest public-sector anti-retroviral treatment (ART) programme in the world, anti-retroviral coverage in adults was only 40.2% in 2008. However, longitudinal studies of who is accessing the South African public-sector ART programme are scarce. This study therefore had one main research question: who is accessing public-sector ART in the Free State Province, South Africa? The study aimed to extend the current literature by investigating, in a quantitative manner and using a longitudinal study design, the participants enrolled in the public-sector ART programme in the period 2004-2006 in the Free State Province of South Africa.</p> <p>Methods</p> <p>Differences in the demographic (age, sex, population group and marital status) socio-economic (education, income, neo-material indicators), geographic (travel costs, relocation for ART), and medical characteristics (CD4, viral load, time since first diagnosis, treatment status) among 912 patients enrolled in the Free State public-sector ART programme between 2004 and 2006 were assessed with one-way analysis of variance, Bonferroni post-hoc analysis, and cross tabulations with the chi square test.</p> <p>Results</p> <p>The patients accessing treatment tended to be female (71.1%) and unemployed (83.4%). However, although relatively poor, those most likely to access ART services were not the most impoverished patients. The proportion of female patients increased (<it>P </it>< 0.05) and their socio-economic situation improved between 2004 and 2006 (<it>P </it>< 0.05). The increasing mean transport cost (<it>P </it>< 0.05) to visit the facility is worrying, because this cost is an important barrier to ART uptake and adherence. Encouragingly, the study results revealed that the interval between the first HIV-positive diagnosis and ART initiation decreased steadily over time (<it>P </it>< 0.05). This was also reflected in the increasing baseline CD4 cell count at ART initiation (<it>P </it>< 0.05).</p> <p>Conclusions</p> <p>Our analysis showed significant changes in the demographic, socio-economic, geographic, and medical characteristics of the patients during the first three years of the programme. Knowledge of the characteristics of these patients can assist policy makers in developing measures to retain them in care. The information reported here can also be usefully applied to target patient groups that are currently not reached in the implementation of the ART programme.</p

Spatial Distribution of, and Risk Factors for, Opisthorchis viverrini Infection in Southern Lao PDR

The liver fluke Opisthorchis viverrini mainly occurs in Lao PDR and Thailand. Humans become infected through the consumption of raw or insufficiently cooked freshwater fish. Chronic infections may lead to severe liver (bile duct) diseases that eventually develop into a bile duct cancer with extremely poor prognosis. Current control efforts aim at preventing heavy morbidity and mortality. In recent years, spatial modeling, using data from well designed surveys, has been employed to better understand the distribution and determinants of parasitic diseases for guiding subsequent control. However, a spatial modeling approach has not been used for O. viverrini before. The purpose of the current study was to map the distribution of O. viverrini infection in Champasack province in southern Lao PDR, to identify risk factors of infection, and to predict the distribution at non-surveyed locations. We found that the risk of O. viverrini infection is higher for people living in close proximity to freshwater bodies, whereas the lack of sanitation sustained environmental contamination and transmission. High risk zones in Champasack province are concentrated in the Mekong River corridor, and hence control efforts should be targeted along the Mekong River

Assessing household wealth in health studies in developing countries: a comparison of participatory wealth ranking and survey techniques from rural South Africa

BACKGROUND: Accurate tools for assessing household wealth are essential for many health studies in developing countries. Household survey and participatory wealth ranking (PWR) are two approaches to generate data for this purpose. METHODS: A household survey and PWR were conducted among eight villages in rural South Africa. We developed three indicators of household wealth using the data. One indicator used PWR data only, one used principal components analysis to combine data from the survey, while the final indicator used survey data combined in a manner informed by the PWR. We assessed internal consistency of the indices and assessed their level of agreement in ranking household wealth. RESULTS: Food security, asset ownership, housing quality and employment were important indicators of household wealth. PWR, consisting of three independent rankings of 9671 households, showed a high level of internal consistency (intraclass correlation coefficient 0.81, 95% CI 0.79-0.82). Data on 1429 households were available from all three techniques. There was moderate agreement in ranking households into wealth tertiles between the two indicators based on survey data (spearman rho = 0.69, kappa = 0.43), but only limited agreement between these techniques and the PWR data (spearman rho = 0.38 and 0.31, kappa = 0.20 and 0.17). CONCLUSION: Both PWR and household survey can provide a rapid assessment of household wealth. Each technique had strengths and weaknesses. Reasons for differences might include data inaccuracies or limitations in the methods by which information was weighted. Alternatively, the techniques may measure different things. More research is needed to increase the validity of measures of socioeconomic position used in health studies in developing countries