Risk factors for sporadic human infection with shiga toxin-producing Escherichia coli in South Australia

This paper reports the findings from a preliminary study seeking to identify risk factors for sporadic human infection with shiga toxin-producing Escherichia coli (STEC) in South Australia. This phase of the study, conducted between February and September 2002, aimed to make recommendations regarding study methodology, and provided an opportunity to identify any potential risk factors for STEC infections in South Australia. The study design was a prospective age-matched case control study. A case was defined as a person with macroscopic or microscopic evidence of blood in a faecal specimen, and in which a gene associated with the production of shiga toxin (stx 1 or 2) was identified. Two community controls per case were randomly selected from the Social Environmental Risk Context Information System database. Eleven cases and 22 controls were enrolled in the pilot phase of the case control study. Cases were more likely than controls to have eaten berries, including strawberries, blueberries, and blackberries, in the 10 days preceding illness (Mantel Haenszel matched OR 11; 95 per cent CI 1.26-96.12). No other exposures were significantly associated with illness. Due to the small number of study participants, the power of the study was insufficient to expect any significant results. National participation will be vital to obtain sufficient cases in a realistic time, however this would necessitate more consistent ascertainment and reporting of STEC disease between the states and territories

FE Simulation of the Stress-Strain State during Shear-Compression Testing and Asymmetric Three-Roll Rolling Process

A three-roll rolling process is a significant technique in the production of wire rod, round bars and hexagonal profiles for structural applications. Better mechanical properties of wire rod, round bars and hexagonal profiles can be achieved due to large plastic deformation by the three-roll rolling process. Asymmetric rolling is a novel technique characterized by a kinematic asymmetry linked to the difference in peripheral speed of the rolls, able to introduce additional shear strains through the bar thickness. Physical simulation of shear strain, which is similar to that occurring in asymmetric three-roll rolling process, is very important for design of technology of producing ultrafine grain materials. Shear testing is complicated by the fact that a state of large shear is not easily achievable in most specimen geometries. Application of the shear-compression testing and specimen geometry to physical simulation of asymmetric three-roll rolling process is discussed in the paper. FEM simulation and comparison of the stress-strain state during shear-compression testing and asymmetric three-roll rolling process is presented. The results of investigation can be used to optimize the physical simulation of asymmetric three-roll rolling processes and for design of technology of producing ultrafine grain materials by severe plastic deformation

Refrigeration and Air-Conditioning

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