Application of the arbitrary Eulerian Lagrangian finite element formulation to the thermomechanical simulation of casting processes, with focus on pipe shrinkage prediction

International audienceThe Arbitrary Lagrangian-Eulerian formulation (ALE) has become an indispensable component of finite element thermomechanical computations of casting processes. As it is an intermediate formulation between the Lagrangian formulation (material convected mesh) and the Eulerian one (fixed mesh), it allows the simultaneous computation of important phenomena: Deformation and stresses affecting solidified regions, yielding the computation of air gap evolution at part/mold interfaces. In such regions, the formulation is essentially Lagrangian. Thermosolutal convection flow in the non solidified regions; here the ALE formulation tends to a pure Eulerian one (stationary mesh). Free surface evolution at top of risers, leading to the prediction of pipe defects (macroshrinkage). In this case the ALE formulation allows the follow up of the free surface. After a brief reminder of the constitutive equations to be used in thermomechanical modeling of solidification, the mechanical equations are presented and their resolution in the context of FEM-ALE. We insist on the transport analysis, a key-point of ALE, and present a validation of the original scheme that is used here. Finally, we focus on the prediction of pipe shrinkage formation and show two industrial examples

Patent Foramen Ovale Closure or Anticoagulation vs. Antiplatelets after Stroke

BACKGROUND Trials of patent foramen ovale (PFO) closure to prevent recurrent stroke have been inconclusive. We investigated whether patients with cryptogenic stroke and echocardiographic features representing risk of stroke would benefit from PFO closure or anticoagulation, as compared with antiplatelet therapy. METHODS In a multicenter, randomized, open-label trial, we assigned, in a 1:1:1 ratio, patients 16 to 60 years of age who had had a recent stroke attributed to PFO, with an associated atrial septal aneurysm or large interatrial shunt, to transcatheter PFO closure plus long-term antiplatelet therapy (PFO closure group), antiplatelet therapy alone (antiplatelet-only group), or oral anticoagulation (anticoagulation group) (randomization group 1). Patients with contraindications to anticoagulants or to PFO closure were randomly assigned to the alternative noncontraindicated treatment or to antiplatelet therapy (randomization groups 2 and 3). The primary outcome was occurrence of stroke. The comparison of PFO closure plus antiplatelet therapy with antiplatelet therapy alone was performed with combined data from randomization groups 1 and 2, and the comparison of oral anticoagulation with antiplatelet therapy alone was performed with combined data from randomization groups 1 and 3. RESULTS A total of 663 patients underwent randomization and were followed for a mean (+/- SD) of 5.3 +/- 2.0 years. In the analysis of randomization groups 1 and 2, no stroke occurred among the 238 patients in the PFO closure group, whereas stroke occurred in 14 of the 235 patients in the antiplatelet-only group (hazard ratio, 0.03; 95% confidence interval, 0 to 0.26; P<0.001). Procedural complications from PFO closure occurred in 14 patients (5.9%). The rate of atrial fibrillation was higher in the PFO closure group than in the antiplatelet-only group (4.6% vs. 0.9%, P = 0.02). The number of serious adverse events did not differ significantly between the treatment groups (P = 0.56). In the analysis of randomization groups 1 and 3, stroke occurred in 3 of 187 patients assigned to oral anticoagulants and in 7 of 174 patients assigned to antiplatelet therapy alone. CONCLUSIONS Among patients who had had a recent cryptogenic stroke attributed to PFO with an associated atrial septal aneurysm or large interatrial shunt, the rate of stroke recurrence was lower among those assigned to PFO closure combined with antiplatelet therapy than among those assigned to antiplatelet therapy alone. PFO closure was associated with an increased risk of atrial fibrillation

Pru p 7 sensitization is a predominant cause of severe, cypress pollen‐associated peach allergy

International audienceBACKGROUND:Peach is a common elicitor of food allergic reactions. Peach-induced immediate reactions may occur as benign pollen-food syndromes, usually due to birch pollen-related PR-10 cross-reactivity in temperate climates, and as potentially severe primary food allergies, predominantly related to nsLTP Pru p 3 in Mediterranean regions. The newly described peach allergen Pru p 7 has gained recent attention as a potential peach allergy severity marker. Sensitization to Pru p 7 and its allergenic homologues of the gibberellin-regulated protein family occurs in areas with high Cupressaceae tree pollen exposure.OBJECTIVE:We sought to investigate the distribution, clinical characteristics and molecular associations of Pru p 7 sensitization among subjects with suspected peach allergy in different regions of France.METHODS:Subjects with suspected peach allergy (n = 316) were included. Diagnostic work-up was performed according to current guidelines, including open food challenge when required. IgE antibody measurements and competition experiments were performed using the ImmunoCAP assay platform.RESULTS:Sensitization to Pru p 7 was present in 171 (54%) of all subjects in the study and in 123 of 198 (62%) diagnosed as peach allergic, more than half of whom were sensitized to no other peach allergen. Frequency and magnitude of Pru p 7 sensitization were associated with the presence of peach allergy, the clinical severity of peach-induced allergic reactions and the level of cypress pollen exposure. Cypress pollen extract completely outcompeted IgE binding to Pru p 7. Pru p 7 was extremely potent in basophil activation tests.CONCLUSION AND CLINICAL RELEVANCE:A subtype of Cupressaceae pollinosis, characterized by Pru p 7 sensitization, can be an underlying cause of severe peach allergy