Computational Modeling of Failure Processes in Polymers

This paper deals with the modeling of the key mechanisms involved in the fracture of polymers: shear yielding and crazing. Along with the continuum model for shear yielding, we will discuss a recently proposed cohesive surface model for crazing. Applications to be presented include the study of the competition between the two mechanisms during growth of a mode I crack, and a numerical investigation of the role of localized deformations in failure of a polymer blend

Chest computed tomography in severe bronchopulmonary dysplasia:Comparing quantitative scoring methods

Purpose: Bronchopulmonary dysplasia (BPD) is the most common complication of extreme preterm birth and structural lung abnormalities are frequently found in children with BPD. To quantify lung damage in BPD, three new Hounsfield units (HU) based chest-CT scoring methods were evaluated in terms of 1) intra- and inter-observer variability, 2) correlation with the validated Perth-Rotterdam-Annotated-Grid-Morphometric-Analysis (PRAGMA)-BPD score, and 3) correlation with clinical data. Methods: Chest CT scans of children with severe BPD were performed at a median of 7 months corrected age. Hyper- and hypo-attenuated regions were quantified using PRAGMA-BPD and three new HU based scoring methods (automated, semi-automated, and manual). Intra- and inter-observer variability was measured using intraclass correlation coefficients (ICC) and Bland-Altman plots. The correlation between the 4 scoring methods and clinical data was assessed using Spearman rank correlation. Results: Thirty-five patients (median gestational age 26.1 weeks) were included. Intra- and inter-observer variability was excellent for hyper- and hypo-attenuation regions for the manual HU method and PRAGMA-BPD (ICCs range 0.80–0.97). ICC values for the semi-automated HU method were poorer, in particular for the inter-observer variability of hypo- (0.22–0.71) and hyper-attenuation (-0.06–0.89). The manual HU method was highly correlated with PRAGMA-BPD score for both hyper- (ρs0.92, p &lt; 0.001) and hypo-attenuation (ρs0.79, p &lt; 0.001), while automated and semi-automated HU methods showed poor correlation for hypo- (ρs &lt; 0.22) and good correlation for hyper-attenuation (ρs0.72–0.74, p &lt; 0.001). Several scores of hyperattenuation correlated with the use of inhaled bronchodilators in the first year of life; two hypoattenuation scores correlated with birth weight. Conclusions: PRAGMA-BPD and the manual HU method have the best reproducibility for quantification of CT abnormalities in BPD.</p

National EPOS initiatives and participation to the EPOS integration plan

European Plate Observing System (EPOS) is designed on a three-level architecture. The national research infrastructures (NRIs) constitute the backbone of the EPOS delivery framework, where data are generated, processed, analyzed and archived. These data are then integrated by thematic core services (TCS) and distributed through the centralized integrated core services (ICS). In this architecture, data provision from the NRIs is an essential element for the sustainable operation of the EPOS research infrastructure (RI). National EPOS initiatives in various countries in Europe are developed thanks to the increased awareness of the importance of FAIR (Findable, Accessible, Interoperable and Reusable) data management in science. As such, out of the 14 countries (13 members and one observer) that constitute the EPOS European Research Infrastructure Consortium (EPOS-ERIC), 11 have dedicated EPOS consortia established and included in the national roadmaps for research infrastructures. Moreover, there are in total 24 countries involved in the EPOS delivery framework where 10 are not yet members of EPOS-ERIC. However, the diversity of regulations and procedures adopted in different countries, hampers the development of dedicated EPOS consortia contributing to sustainability. In this paper, the national EPOS initiatives are discussed in order to emphasize synergies achieved and the shared efforts to build the EPOS RI during its life-cycle (the design, preparation, implementation, and pilot operational phases), tackling the challenge of sustainable operation.publishedVersio

The clinical profile of right temporal lobe atrophy

Frontotemporal lobar degeneration is currently associated with three syndromic variants. Disorders of speech and language figure prominently in two of the three variants, and are associated with left-sided frontotemporal atrophy. The detailed characterization of these syndromes contrasts with the relative paucity of information relating to frontotemporal lobar degeneration primarily affecting the right cerebral hemisphere. The objective of this study was to identify the clinical profile associated with asymmetrical, predominantly right-sided, temporal lobe atrophy. Twenty patients with predominant right temporal lobe atrophy were identified on the basis of blinded visual assessment of the MRI scans. The severity of right temporal lobe atrophy was quantified using volumetric analysis of the whole temporal lobes, the amygdala and the hippocampus. Profiles of cognitive function, behavioural and personality changes were obtained on each patient. The pattern of atrophy and the clinical features were compared with those observed in a group of patients with semantic dementia and predominant left-sided temporal lobe atrophy. The mean right temporal lobe volume in the right temporal lobe atrophy group was reduced by 37%, with the mean left temporal lobe volume reduced by 19%. There was marked atrophy of the right hippocampus and right amygdala, with mean volumes reduced by 41 and 51%, respectively (left hippocampus and amygdala volumes were reduced by 18 and 33%, respectively). The most prominent cognitive deficits were impairment of episodic memory and getting lost. Prosopagnosia was a symptom in right temporal lobe atrophy patients. These patients also exhibited a variety of behavioural symptoms including social disinhibition, depression and aggressive behaviour. Nearly all behavioural disorders were more prevalent in the right temporal lobe atrophy patient group than the semantic dementia group. Symptoms particular to the right temporal lobe atrophy patient group included hyper-religiosity, visual hallucinations and cross-modal sensory experiences. The combination of clinical features associated with predominant right temporal lobe atrophy differs significantly from those associated with the other syndromes associated with focal degeneration of the frontal and temporal lobes and it is, therefore, proposed that this right temporal variant should be considered a separate syndromic variant of frontotemporal lobar degeneration