Thermoforming of foam sheet

Thermoforming is a widely used process for the manufacture of foam sheet products. Polystyrene foam food trays for instance can be produced by first heating the thermoplastic foam sheet, causing the gas contained to build up pressure and expand, after which a vacuum pressure can be applied to draw the sheet in the required form on the mould. This production method appears to be a very sensitive process with respect to e.g. the sheet temperature, the pressures applied and the cooling time. More problems can be foreseen when for environmental reasons the blowing agent will be adapted (for instance replaced by a gas with a lower molecular weight). To gain more insight in the occuring phenomena the large deformations of a foam structure have been analysed using finite element modelling. To this end a constitutive model has to be defined. Starting from the basic theory given by Gibson & Ashby [1], the behaviour of a closed cubic cell has been elaborated for large strains. The total stiffness is then the sum of the contributions of the edges and faces of the cell and the gas contained in it. The large deformations cause anisotropy of the cells [2], which influences their tangential stiffness. The constitutive model developed here includes the effects of internal gas pressure and the evolving anisotropy

Effectiveness of a Multidimensional Randomized Control Intervention to Reduce Quartz Exposure Among Construction Workers

There is little evidence with respect to the effectiveness of intervention programs that focus on the reduction of occupational quartz exposure in the construction industry. This article evaluates the effectiveness of a multidimensional intervention which was aimed at reducing occupational quartz exposure among construction workers by increasing the use of technical control measures. Eight companies participating in the cluster randomized controlled trial were randomly allocated to the intervention (four companies) or control condition (four companies). The multidimensional intervention included engineering, organizational, and behavioural elements at both organizational and individual level. Full-shift personal quartz exposure measurements and detailed observations were conducted before and after the intervention among bricklayers, carpenters, concrete drillers, demolishers, and tuck pointers (n = 282). About 59% of these workers measured at baseline were reassessed during follow-up. Bayesian hierarchical models were used to evaluate the intervention effect on exposure levels. Concrete drillers in the intervention group used technical control measures, particularly water suppression, for a significantly greater proportion of the time spent on abrasive tasks during follow-up compared to baseline (93 versus 62%; P < 0.05). A similar effect, although not statistically significant, was observed among demolishers. A substantial overall reduction in quartz exposure (73 versus 40% in the intervention and control group respectively; P < 0.001) was observed for concrete drillers, demolishers, and tuck pointers. The decrease in exposure in the intervention group compared to controls was significantly larger for demolishers and tuck pointers, but not for concrete drillers. The observed effect could at least partly be explained by the introduced interventions; the statistically significant increased use of control measures among concrete drillers explains the observed effect to some extent in this job category only. Sensitivity analyses indicated that the observed decrease in exposure may also partly be attributable to changes in work location and abrasiveness of the tasks performed. Despite the difficulties in assessing the exact magnitude of the intervention, this study showed that the structured intervention approach at least partly contributed to a substantial reduction in quartz exposure among high exposed construction workers

Mutations of MLC1 (KIAA0027), Encoding a Putative Membrane Protein, Cause Megalencephalic Leukoencephalopathy with Subcortical Cysts

Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is an autosomal recessive disorder characterized by macrocephaly, deterioration of motor functions with ataxia, and spasticity, eventuating in mental decline. The brain appears swollen on magnetic resonance imaging, with diffuse white-matter abnormalities and the invariable presence of subcortical cysts. MLC was recently localized on chromosome 22q(tel). We have narrowed down the critical region by linkage analysis of 11 informative families with MLC to a region of ∼250 kb, containing four known genes. One family with two patients who were siblings did not display linkage between the MLC phenotype and any of the analyzed microsatellite markers on chromosome 22q(tel), suggesting genetic heterogeneity and the existence of at least a second MLC locus. The maximum two-point LOD score for the 11 families was 6.6 at recombination fraction .02. Twelve different mutations in seven informative and six uninformative families were found in one of the candidate genes, KIAA0027, which we renamed “MLC1.” The gene encodes a putative membrane protein with eight predicted transmembrane domains. The patients of one family were compound heterozygotes for mutations that both introduced stop codons. The mutations further included frameshifts, splice-acceptor mutations, a putative splice-donor mutation, and amino acid substitutions of residues in predicted transmembrane domains. These data provide strong evidence that mutations of MLC1 cause the disease

Development and validation of a prognostic score for long-term transplant-free survival in autoimmune hepatitis type 1

Background: No prognostic score is currently available for long-term survival in autoimmune hepatitis (AIH) patients. Objective: The aim of this study was to develop and validate such a prognostic score for AIH patients at diagnosis. Methods: The prognostic score was developed using uni- &amp; multivariate Cox regression in a 4-center Dutch cohort and validated in an independent 6-center Belgian cohort. Results: In the derivation cohort of 396 patients 19 liver transplantations (LTs) and 51 deaths occurred (median follow-up 118 months; interquartile range 60–202 months). In multivariate analysis age (hazard ratio [HR] 1.045; p &lt; 0.001), non-caucasian ethnicity (HR 1.897; p = 0.045), cirrhosis (HR 3.266; p &lt; 0.001) and alanine aminotransferase level (HR 0.725; p = 0.003) were significant independent predictors for mortality or LT (C-statistic 0.827; 95% CI 0.790–0.864). In the validation cohort of 408 patients death or LT occurred in 78 patients during a median follow-up of 74 months (interquartile range: 25–142 months). Predicted 5-year event rate did not differ from observed event rate (high risk group 21.5% vs. 15.7% (95% CI: 6.3%–24.2%); moderate risk group 5.8% versus 4.3% (95% CI: 0.0%–9.1%); low risk group 1.9% versus 5.4% (95% CI: 0.0%–11.4%); C-statistic 0.744 [95% CI 0.644–0.844]). Conclusions: A Dutch-Belgian prognostic score for long-term transplant-free survival in AIH patients at diagnosis was developed and validated.</p

Parsing the components of forgiveness: Psychological and neural mechanisms

Forgiveness―a shift in motivation away from retaliation and avoidance towards increased goodwill for the perceived wrongdoer―plays a vital role in restoring social relationships, and positively impacts personal wellbeing and society at large. Parsing the psychological and neurobiological mechanisms of forgiveness contributes theoretical clarity, yet has remained an outstanding challenge because of conceptual and methodological difficulties in the field. Here, we critically examine the neuroscientific evidence in support of a theoretical framework which accounts for the proximate mechanisms underlying forgiveness. Specifically, we integrate empirical evidence from social psychology and neuroscience to propose that forgiveness relies on three distinct and interacting psychological macro-components: cognitive control, perspective taking, and social valuation. The implication of the lateral prefrontal cortex, temporoparietal junction, and ventromedial prefrontal cortex, respectively, is discussed in the brain networks subserving these distinct component processes. Finally, we outline some caveats that limit the translational value of existing social neuroscience research and provide directions for future research to advance the field of forgiveness