Efficient implementation of a component-based joint model

This paper deals with a nonlinear analysis of beam-to-column steel joint. The connection uses an end-plate welded to the steel cross-section of a steel-concrete composite beam and bolted to the column flange. The proposed model developed herein combines the knowledge of prior studies that used the component-based approach, on one hand and the Finite Element algorithmsin plasticity, on second hand. The originality of this work is to efficiently take into account possible gaps between the end-plate and the column flange in case of plastic deformation of some components of the joint during the cyclic loading. The numerical investigation aims topredict the behavior of this type of joint in presence of the gap during the cyclic loading

Remdesivir and three other drugs for hospitalised patients with COVID-19: final results of the WHO Solidarity randomised trial and updated meta-analyses.

BACKGROUND World Health Organization expert groups recommended mortality trials of four repurposed antiviral drugs - remdesivir, hydroxychloroquine, lopinavir, and interferon beta-1a - in patients hospitalized with coronavirus disease 2019 (Covid-19). METHODS We randomly assigned inpatients with Covid-19 equally between one of the trial drug regimens that was locally available and open control (up to five options, four active and the local standard of care). The intention-to-treat primary analyses examined in-hospital mortality in the four pairwise comparisons of each trial drug and its control (drug available but patient assigned to the same care without that drug). Rate ratios for death were calculated with stratification according to age and status regarding mechanical ventilation at trial entry. RESULTS At 405 hospitals in 30 countries, 11,330 adults underwent randomization; 2750 were assigned to receive remdesivir, 954 to hydroxychloroquine, 1411 to lopinavir (without interferon), 2063 to interferon (including 651 to interferon plus lopinavir), and 4088 to no trial drug. Adherence was 94 to 96% midway through treatment, with 2 to 6% crossover. In total, 1253 deaths were reported (median day of death, day 8; interquartile range, 4 to 14). The Kaplan-Meier 28-day mortality was 11.8% (39.0% if the patient was already receiving ventilation at randomization and 9.5% otherwise). Death occurred in 301 of 2743 patients receiving remdesivir and in 303 of 2708 receiving its control (rate ratio, 0.95; 95% confidence interval [CI], 0.81 to 1.11; P = 0.50), in 104 of 947 patients receiving hydroxychloroquine and in 84 of 906 receiving its control (rate ratio, 1.19; 95% CI, 0.89 to 1.59; P = 0.23), in 148 of 1399 patients receiving lopinavir and in 146 of 1372 receiving its control (rate ratio, 1.00; 95% CI, 0.79 to 1.25; P = 0.97), and in 243 of 2050 patients receiving interferon and in 216 of 2050 receiving its control (rate ratio, 1.16; 95% CI, 0.96 to 1.39; P = 0.11). No drug definitely reduced mortality, overall or in any subgroup, or reduced initiation of ventilation or hospitalization duration. CONCLUSIONS These remdesivir, hydroxychloroquine, lopinavir, and interferon regimens had little or no effect on hospitalized patients with Covid-19, as indicated by overall mortality, initiation of ventilation, and duration of hospital stay. (Funded by the World Health Organization; ISRCTN Registry number, ISRCTN83971151; ClinicalTrials.gov number, NCT04315948.)

Efficient implementation of a component-based joint model

This paper deals with a nonlinear analysis of beam-to-column steel joint. The connection uses an end-plate welded to the steel cross-section of a steel-concrete composite beam and bolted to the column flange. The proposed model developed herein combines the knowledge of prior studies that used the component-based approach, on one hand and the Finite Element algorithmsin plasticity, on second hand. The originality of this work is to efficiently take into account possible gaps between the end-plate and the column flange in case of plastic deformation of some components of the joint during the cyclic loading. The numerical investigation aims topredict the behavior of this type of joint in presence of the gap during the cyclic loading

Manganese orchestrates a metabolic shift leading to the increased bioconversion of glycerol into α-ketoglutarate.

Glycerol is a major by-product of the biodiesel industry and its transformation into value-added products is an ongoing technological challenge. Here we report on the ability of the nutritionally-versatile Pseudomonas fluorescens to synthesize copious amount of α-ketoglutarate (KG) in a glycerol medium supplemented with manganese (Mn). The enhanced production of this keto-acid was mediated by the increased activities of isocitrate dehydrogenase (ICDH)-(NAD)P dependent and aminotransaminases. At stationary phase of growth when the optimal quantity of KG was recorded, these enzymes exhibited maximal activities. Two isoforms of pyruvate carboxylase (PC) that were identified in the Mn-treated cells provided an effective route for the synthesis of oxaloacetate, a metabolite critical in the production of KG. Furthermore, the increased activities of phosphoenol pyruvate carboxylase (PEPC) and pyruvate orthophosphate dikinase (PPDK) ensured the efficacy of this KG-generating metabolic system by supplying pyruvate and ATP from the oxaloacetate synthesized by PC. Mn-exposed whole cells converted 90% of industrial glycerol into KG. This Mn-evoked metabolic network can be optimized into the economic transformation of glycerol into KG

Experimental tests on bolted end-plate connections using thermal insulation layer attached to steel structures

International audienceThis paper deals with the mechanical performances of thermal break for external steel structures (balconies, passageways) attached to a steel facade with external thermal insulation. The proposed solution is composed of a PVC or plywood layers inserted between an end-plate connection and a steel column. Static and cyclic tests are performed on a cantilever beam connected to a steel column by a thermal break in order to investigate the effect of the thermal insulation layer on the rotational stiffness, bending moment resistances and failure modes. These tests highlight on one hand the influence of the thermal insulation and on another hand, the bolt configuration (extended and flush end-plate, stiffeners, RHS or I profile). © SDSS 2019 - International Colloquium on Stability and Ductility of Steel Structures

Co-rotational planar beam element with generalized elasto-plastic hinges

International audienceSlender elements in framed structures may undergo large displacement and experience highly nonlinear behavior. This paper presents a two-node co-rotational flexible beam with generalized elasto-plastic hinges at the beam ends. A Condensation procedure is used to remove the internal degrees of freedom so that the formulation is easily incorporated with the standard co-rotational approach. A family of asymmetric and convex yield surfaces of super-elliptic shape is considered for the plastic behavior of the hinges. By varying the roundness factor, an infinite number of yield surfaces are obtained making it possible to select the yield function that best fit experimental data of any type of cross-section and material. The nonlinear response of bolted connections subjected to both bending and axial forces are conveniently modeled with such a yield surface. Discrete constitutive equations for the hinge plastic deformations are derived using the implicit scheme for both smooth and non-smooth cases. Numerical examples demonstrate the accuracy of the model in predicting the large displacement inelastic response of framed structures. Effect of the roundness factor on the ultimate load strongly depends on the structure typology. It was observed that cyclic loading produces pinching effect, cyclic softening and ductile behavior. Those effects are more pronounced with anisotropic yield criteria. © 2017 Elsevier Lt

Biophysical Aspects of Lipid Digestion in Human Breast Milk and Similac ™ Infant Formulas

Abstract Physico-chemical properties of human breast milk were compared to four Similac ™ infant formulas, and correlated with in vitro free fatty acid bioaccessibility using a simulated gastrointestinal system (TIM-1). Viscoelastic measurements, as a function of pH (pH 6.5 to 3.0) and shear rate, showed lower viscosities in breast milk compared to infant formulas. Droplet size and distribution measurements showed distinct differences between the tested formulas and breast milk. During lipid digestion, a lag period was observed for only breast milk. The rate of lipolysis was found to be higher in breast milk compared to Similac ™ formulas. The total bioaccessible free fatty acids for Advance infant formula and breast milk were not statistically different for the in vitro TIM-1 model and the shifted-logistical model using one-way ANOVA (p<0.05) with a Tukey's Multiple Comparison Test. All other infant formulas had significantly lower free fatty acid bioaccessibilities at the end of the simulated digestion. A positive correlation between rate of lipolysis and droplet surface area per gram for the Similac ™ infant formulas was found. However, breast milk did not follow that trend, suggesting the possible involvement of other factors in rate of lipolysis for breast milk