BACKGROUND: There has been little formal analysis of laboratory systems in resource-limited settings, despite widespread consensus around the importance of a strong laboratory infrastructure. OBJECTIVES: This study details the informational challenges faced by the laboratory at Kamuzu Central Hospital, a tertiary health facility in Malawi; and proposes ways in which informatics can bolster the efficiency and role of low-resource laboratory systems. METHODS: We evaluated previously-collected data on three different aspects of laboratory use. A four-week quality audit of laboratory test orders quantified challenges associated with collecting viable specimens for testing. Data on tests run by the laboratory over a one-year period described the magnitude of the demand for laboratory services. Descriptive information about the laboratory workflow identified informational process breakdowns in the pre-analytical and post-analytical phases and was paired with a 24-hour sample of laboratory data on results reporting. RESULTS: The laboratory conducted 242 242 tests over a 12-month period. The four-week quality audit identified 54% of samples as untestable. Prohibitive paperwork errors were identified in 16% of samples. Laboratory service workflows indicated a potential process breakdown in sample transport and results reporting resulting from the lack of assignment of these tasks to any specific employee cadre. The study of result reporting time showed a mean of almost six hours, with significant variation. CONCLUSIONS: This analysis identified challenges in each phase of laboratory testing. Informatics could improve the management of this information by streamlining test ordering and the communication of test orders to the laboratory and results back to the ordering physician.

BACKGROUND: Temporary intravascular shunts (TIVSs) can replace immediate definitive repair as a damage control procedure in vascular trauma. We evaluated their use in an urban trauma centre with a high incidence of penetrating trauma. METHOD: A retrospective chart review of all patients treated with a TIVS in a single centre between January 2000 and December 2009. RESULTS: Thirty-five TIVSs were placed during the study period: 22 were part of a damage control procedure, 7 were inserted at a peripheral hospital without vascular surgical expertise prior to transfer, and 6 were used during fixation of a lower limb fracture with an associated vascular injury. There were 7 amputations and 5 deaths, 4 of the TIVSs thrombosed, and a further 3 dislodged or migrated. Twenty-five patients underwent definitive repair with an interposition graft, 1 primary anastomosis was achieved, and 1 extra-anatomical bypass was performed. Five patients with non-viable limbs had the vessel ligated. CONCLUSIONS: A TIVS in the damage control setting is both life- and limb-saving. These shunts can be inserted safely in a facility without access to a surgeon with vascular surgery experience if there is uncontrollable bleeding or the delay to definitive vascular surgery is likely to be more than 6 hours. A definitive procedure should be performed within 24 hours

Equal channel angular pressing is one of the techniques in metal forming processes in which an ultra-large plastic strain is imposed on a bulk material in order to make ultra-fine grained and nanocrystalline metals and alloys. The technique is a viable forming procedure to extrude materials by use of specially designed channel dies without substantially changing the geometry by imposing severe plastic deformation. This technique has the potential for high strain rate superplasticity by effective grain refinement to the level of the submicronscale or nanoscale. We review recent work on new trends in equal channel angular pressing techniques and the manufacturing of die-sets used for the processing of metals and alloys. We also experimented on a copper alloy using the equal channel angular pressing technique to examine the microstructural, mechanical and hardness properties of the ultra-fine grained and nanocrystalline materials produced. After deformation, all samples were subjected to a hardness test and the results showed improved mechanical behaviour of the ultra-fine grained copper alloy that was developed. This research provides an opportunity to examine the significance of the equal channel angular pressing process for metals and alloys. That is, these ultra-fine grained materials can be used in the manufacturing of semi-finished products used in the power, aerospace, medical and automotive industries.

Apresenta-se uma metodologia para modelar elementos estruturais de concreto armado tridimensionais através de elementos finitos com descontinuidade incorporada no contexto da aproximação contínua de descontinuidades fortes. Utilizam-se conceitos de teoria de misturas para representar o concreto armado como um material composto de matriz (concreto) com feixes de fibras (barras de aço) longas em diferentes direções. O efeito das barras é proporcionado por modelos constitutivos fenomenológicos, desenvolvidos para reproduzir o comportamento axial não-linear, assim como efeitos provenientes de deslizamento por perda de aderência e ação de pino. O presente artigo foca os modelos constitutivos dos componentes e as condições de compatibilidade escolhidas para constituir o composto. Para ilustrar a aplicabilidade da metodologia proposta, apresentam-se análises numéricas de testes experimentais de elementos de concreto armado existentes.

This paper presents a methodology to model three-dimensional reinforced concrete members by means of embedded discontinuity elements based on the Continuous Strong Discontinuous Approach (CSDA). Mixture theory concepts are used to model reinforced concrete as a 3D composite material constituted of concrete with long fiber bundles (rebars) oriented in different directions embedded in it. The effects of the rebars are provided by phenomenological constitutive models designed to reproduce the axial non-linear behavior, as well as bond-slip and dowel action. This paper is focused on the constitutive models assumed for the components and the compatibility conditions chosen to constitute the composite. Numerical analyses of existing experimental reinforced concrete members are presented, illustrating the applicability of the methodology.