Observing Inequality: Can Ergonomic Observations Help Interventions Transform the Role of Gender in Work Activity?

Computer Supported Cooperative Work (CSCW) - Work activity ergonomics (sometimes called francophone ergonomics) draws heavily on observation in order to support transformation of work to arrive at...     

Escherichia coli O157:H7 outbreak linked to raw milk cheese in Quebec, Canada: use of exact probability calculation and casecase study approaches to foodborne outbreak investigation

The analytical studies used to investigate foodborne outbreak are mostly case-control or retrospective cohort studies. However, these studies can be complex to perform and susceptible to biases. This article addresses basic principles of epidemiology, probability, and the use of case-case design to identify the source of an Escherichia coli O157:H7 outbreak linked to raw milk cheese consumption in Quebec, Canada; a small number of cases with the same pulsed-field gel electrophoresis (PFGE) profile were involved. Between 4 December 2008 and 15 January 2009, a cumulative total of 16 E. coli O157:H7 cases with the same PFGE profile were reported to Quebec public health authorities. Among the first six cases reported, three had consumed raw milk cheese from the same producer (cheese A). Raw milk cheese is consumed by about 2 % of the Quebec population. By using the exact probability calculation, it was found that a significantly higher proportion of E. coli O157:H7 cases (with the specific PFGE profile) than expected had consumed cheese A (P < 0.001). These computations were updated during the course of the investigation to include subsequent cases and gave the same results. A case-case study corroborated this result. This article considers alternative statistical and epidemiological approaches to investigate a foodborne outbreak-in particular with an exact probability calculation and case-case comparisons. This approach could offer a fast and inexpensive alternative to regular case-control studies to target public health actions, particularly during a foodborne outbreak.     

Decellularised Human Umbilical Artery as a Vascular Graft Elicits Minimal Pro-Inflammatory Host Response Ex Vivo and In Vivo

Small diameter (<6 mm) vessel grafts still pose a challenge for scientists worldwide. Decellularised umbilical artery (dUA) remains promising as small diameter tissue engineered vascular graft (TEVG), yet their immunogenicity remains unknown. Herein, we evaluated the host immune responses, with a focus on the innate part, towards human dUA implantation in mice, and confirmed our findings in an ex vivo allogeneic human setup. Overall, we did not observe any differences in the number of circulating white blood cells nor the number of monocytes among three groups of mice (1) dUA patch; (2) Sham; and (3) Mock throughout the study (day −7 to 28). Likewise, we found no difference in systemic inflammatory and anti-inflammatory cytokine levels between groups. However, a massive local remodelling response with M2 macrophages were observed in the dUA at day 28, whereas M1 macrophages were less frequent. Moreover, human monocytes from allogeneic individuals were differentiated into macrophages and exposed to lyophilised dUA to maximize an eventual M1 response. Yet, dUA did not elicit any immediate M1 response as determined by the absence of CCR7 and CXCL10. Together this suggests that human dUA elicits a minimal pro-inflammatory response further supporting its use as a TEVG in an allogeneic setup.     

Processing–formulation–performance relationships of polypropylene/short flax fiber composites

This work is a comprehensive study of the effect of extrusion process parameters and formulation on the properties of polypropylene (PP)/short flax fiber composites. The parameters that were varied during the twin‐screw extrusion process were screw configuration, revolutions per minute (rpm), extrusion temperature, and flow rate. The effect of the feeding zone location of cellulosic fiber was also considered. This study investigates the effect of the formulation, cellulosic fiber content, the presence of a coupling agent, and of a reactive additive on composite performance. The composites were characterized in terms of morphology and microstructure, fiber length, rheological, thermal, and mechanical properties. Sensibility to humidity and recyclability were also considered. When compared with as‐received PP, the tensile strength of injection‐molded parts increased with cellulosic content by up to 40 vol %, and the tensile modulus increased 3.5 times when a combination of coupling and reactive agents was used. Exposed to controlled humidity of 50% during 1 year, these composites exhibited a very low level of humidity uptake around 0.85 wt %. The processability of these materials using a cast film line and the mechanical properties of extruded sheets are also presented. Furthermore, these materials demonstrate a good recyclability using injection molding by keeping the integrality of their mechanical properties after five reprocessing cycles. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41528.     

The effects of vitamin E and selenium intake on oxidative stress and plasma lipids in hamsters fed fish oil

The aim of the present work was to test the effects of large-dose supplementation of vitamin E (Vit E) and selenium (Se), either singly or in combination, on fish oil (FO)-induced tissue lipid peroxidation and hyperlipidemia. The supplementation of Se has been shown to lower blood cholesterol and increase tissue concentrations of the antioxidant glutathione (GSH); however, the effects of Se supplementation, either alone or in combination with supplemental Vit E, on FO-induced oxidative stress and hyperlipidemia have not been studied. Male Syrian hamsters received FO-based diets that contained 14.3 wt% fat and 0.46 wt% cholesterol supplemented with Vit E (129 IU d-α-tocopheryl acetate/kg diet) and/or Se (3.4 ppm as sodium selenate) or that contained basal requirements of both nutrients. The cardiac tissue of hamsters fed supplemental Se showed increased concentrations of lipid hydroperoxides (LPO) but decreased oxidized glutathione (GSSG) concentrations. The higher concentrations of LPO in the hearts of Se-supplemented hamsters were not lowered with concurrent Vit E supplementation. In the liver, Se supplementation was associated with higher Se-dependent glutathione peroxidase activity and an increase in the GSH/GSSG ratio, whereas a lower hepatic non-Se-dependent glutathione peroxidase activity was seen with Vit E supplementation. Supplemental intake of Se was associated with lower plasma concentrations of total cholesterol and low density lipoprotein cholesterol plus very low density lipoprotein cholesterol. In view of the pro-oxidative effects of Se supplementation on cardiac tissue, a cautionary approach needs to be taken regarding the plasma lipid-lowering properties of supplemental Se.     

Physiologically based modeling of 3-D vascular networks and CT scan angiography

In this paper, a model-based approach to medical image analysis is presented. It is aimed at understanding the influence of the physiological (related to tissue) and physical (related to image modality) processes underlying the image content. This methodology is exemplified by modeling first, the liver and its vascular network, and second, the standard computed tomography (CT) scan acquisition. After a brief survey on vascular modeling literature, a new method, aimed at the generation of growing three-dimensional vascular structures perfusing the tissue, is described. A solution is proposed in order to avoid intersections among vessels belonging to arterial and/or venous trees, which are physiologically connected. Then it is shown how the propagation of contrast material leads to simulate time-dependent sequences of enhanced liver CT slices.     

Computer-aided method for quantification of cartilage thickness and volume changes using MRI: validation study using a synthetic model

The primary objective of this study was to develop a computer-aided method for the quantification of three-dimensional (3-D) cartilage changes over time in knees with osteoarthritis (OA). We introduced a local coordinate system (LCS) for the femoral and tibial cartilage boundaries that provides a standardized representation of cartilage geometry, thickness, and volume. The LCS can be registered in different data sets from the same patient so that results can be directly compared. Cartilage boundaries are segmented from 3-D magnetic resonance (MR) slices with a semi-automated method and transformed into offset-maps, defined by the LCS. Volumes and thickness are computed from these offset-maps. Further anatomical labeling allows focal volumes to be evaluated in predefined subregions. The accuracy of the automated behavior of the method was assessed, without any human intervention, using realistic, synthetic 3-D MR images of a human knee. The error in thickness evaluation is lower than 0.12 mm for the tibia and femur. Cartilage volumes in anatomical subregions show a coefficient of variation ranging from 0.11% to 0.32%. This method improves noninvasive 3-D analysis of cartilage thickness and volume and is well suited for in vivo follow-up clinical studies of OA knees.     

Les déterminants individuels, interpersonnels et organisationnels de la détresse psychologique en milieu de travail.

Studied determinants of psychological stress in the workplace to test a 2-step model involving 3 organizational stressors (i.e., quantitative work overload, role conflict, and role ambiguity) and 3 types of resources (i.e., individual, interpersonal, and organizational). 636 full-time employees (mean age 37.5 yrs) of 4 organizations completed questionnaires assessing sociodemographic factors, organizational stressors, resources (i.e., locus of control, Type A (coronary prone) behavior, social support from supervisors and colleagues, and decisional latitude), and psychological stress. Interactions among these factors were determined via multiple regression analyses. Several French-language instruments were used, including the Questionnaire on Internal–External Locus of Control in the Workplace (N. Pettersen, 1984) and the Psychiatric Symptom Index (F. W. Ilfeld, 1976). (English abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Solid state transformations of Au-Cu-Pt alloys studied by in-situ X-ray synchrotron radiation and DSC

Seven alloys of the ternary Au-Cu-Pt system, containing 75 or 76.5 wt.% Au with 0–15 wt.% Pt and heat-treated to a fully ordered condition, are examined using in-situ synchrotron radiation to determine transformation temperatures and phases formed, and to investigate mechanisms of ordering and disordering. These experiments are complemented by differential scanning calorimetry. Diffraction data show that the alloys can be separated into three groups according to their stable low-temperature ordered phase(s), namely L1₀, L1₂, or the two combined. Platinum increases transformation temperatures in comparison with binary AuCu, two-phase ordered alloys showing the highest transformation temperatures. Details of the evolution of the X-ray diffraction peak structures upon heating and cooling point to significant differences between mechanisms of disordering and ordering: whereas ordering visibly proceeds at significant undercooling by nucleation and growth, disordering appears, from the visible shifts in peak position, to progress in more homogeneous fashion within the alloy.     

CF/PA12 composite femoral stems: Manufacturing and properties

The fabrication process for a novel carbon fiber-reinforced polymer (polyamide 12) composite femoral stem using inflatable bladder molding was studied. Effect of processing temperature, holding time and applied internal pressure on the consolidation quality of the composite was investigated. Consolidation quality was evaluated by density and void content measurements and scanning electron microscope analysis. As expected, void content (porosities) and presence of large resin pockets were found to increase for lower processing temperature, holding time and applied pressure. Crystallinity as well as melting temperatures measured using differential scanning calorimetry could be related to molding conditions. A progressive reduction of the previous thermal history (crystalline peak of neat composite) and an increase in crystallinity were obtained for higher molding temperature. Static compression testing with void content analysis of molded specimens was used to determine optimal molding conditions. The composite structure molded showed compressive modulus close to cortical bone’s. Compression load at failure of composites molded in optimal conditions were found to be three times higher than those of femoral bone for jumping on one leg or 10 times those for normal gait. The molded composite structure appears to be an excellent candidate for femoral stems used in total hip arthroplasty.