A residual stress analysis involving matter deposit and removal

No abstract provide

Programming Engineering Applications using the Object Oriented FEM code Castem 2000

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Finite-element simulation of a new two-dissipative mechanism model for bulk medium-density polyethylene

International audienceA two-dissipative mechanisms model, associating a Maxwell and an elastoplastic model in parallel, is discussed in order to account for the non-linear viscoelasticity of bulk medium-density polyethylene. On the one hand, the experimental determination of the constitutive equations coefficients is described from a tensile specimen machined from gas pipes. On the other hand, finite-element simulation of the stress relaxation experiment, proposed by Sweeney and Ward, is achieved, which yields a complete analysis of the dissipative mechanisms interaction during the test. The finite-element code built upon this modelling is finally used in a tentative simulation of a cyclic pressure test on a pipe specimen

Multicenter Randomized Double-Blind, Placebo-Controlled Trial GORTEC (Groupe Oncologie Radiotherapie Tete et Cou) 2009-01 Evaluating the Effect of the Regenerating Agent on Radiodermatitis of Head and Neck Cancer Patients.

Concomitant cetuximab and radiation therapy (RT) can induce severe radiodermatitis in patients with head and neck cancer (HNC). OTD70DERM, a regenerating agent (RGTA), is a structural and functional analogue of glycosaminoglycans. Preclinical studies have shown that topical RGTA can markedly reduce radiation-induced mucosal and cutaneous toxicities without tumor protection. The present study aimed to evaluate the effect of topical RGTA on radiodermatitis in patients with HNC undergoing RT and cetuximab, for whom RT-induced skin reactions are frequent and/or severe. The primary endpoint was the incidence of grade ≥2 radiodermatitis. We performed a multicenter, randomized, double-blind, placebo-controlled trial of patients with newly diagnosed HNC undergoing conventionally fractionated RT (70 Gy in 35 fractions) and weekly cetuximab. Patients were randomized 1:1 to receive topical OTD70DERM or placebo on irradiated skin once daily. The National Cancer Institute Common Terminology Criteria for Adverse Events, version 3.0, was used to evaluate radiodermatitis (photographs of radiation zone). The Dermatology Life Quality Index score was also evaluated. All the skin reactions seen on the photographs were scored independently by 2 outside experts. Of the 76 randomized patients (38 in each arm), 72 were available for the final radiodermatitis evaluation (37 in the RGTA arm and 35 in the placebo arm). No significant difference was observed concerning the incidence or duration of grade ≥2 radiodermatitis between the 2 arms (81% for RGTA vs 80% for placebo; P=.9). Also, no significant difference was found between the 2 arms regarding grade ≥2 radiodermatitis evaluated by the 2 experts using the photographs of 68 patients (76% vs 74%; P=.78). Finally, no significant difference was found in the Dermatology Life Quality Index score (score >10, 15% vs 20%; P=.45). Despite the good preclinical rationale, RGTA did not reduce the incidence and severity of radiodermatitis in patients with HNC

Changes in specific leaf area of dominant plants in temperate grasslands along a 2500-km transect in northern China

Abstract Specific leaf area (SLA) is a key trait with great ecological importance as it correlates with whole plant growth. We aimed to investigate how SLA varies with environmental factors at a geographical scale in temperate grasslands. We measured SLA and mass-based leaf nitrogen content (N mass) of four dominant plant genera along a 2500 km climatic gradient in northern China grassland, and correlated SLA with mean annual precipitation (MAP), mean annual temperature (MAT), soil nitrogen concentration (soil N), soil C:N and N mass. Climate accounts much more for SLA variation than soil variables for Stipa, Cleistogens and Carex. SLA of Stipa is negatively associated with MAP and soil N, while positively with MAT, but Cleistogenes and Carex show the opposite. For Leymus, soil N promotes SLA and accounts for largest fraction of SLA variation. Overall, SLA was positively correlated with N mass in semi-arid regions, but not significant in arid regions. The genus-dependent responses of SLA may have consequences on ecosystem functioning, thus may help to predict the community composition and ecosystem functions under future climate scenario. The finding of SLA-N mass trade-off and its susceptibility to precipitation will advance our understanding on plant resource use strategies