132 research outputs found

    Progressive collapse induced by fire and blast

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    Comprehensive finite element modelling of key elements is essential to improve the robustness assessment of structures subjected to a coupled effect of fire and blast. Focusing the attention on steel structures, a method for a realistic multi-hazard approach is presented. The problem has been investigated at the material level first and then at the structural level. The material level was studied performing a detailed experimental investigation in a wide range of strain rates and temperatures. A typical structural steel, namely S355, has been studied. A Split Hopkinson Tensile Bar equipped with a water-cooled induction heating system was used for the mechanical characterisation at high strain rates (300 1/s, 500 1/s and 850 1/s) and in a wide range of temperatures (20C, 200C, 400C, 550C, 700C and 900C). A Hydro-Pneumatic machine and a universal electromechanical testing machine were used for intermediate (5 1/s and 25 1/s) and quasi-static (0.001 1/s) strain rate tests at room temperature, respectively. Results showed that the S355 structural steel is strain rate sensitive, keeping its strain hardening capacity with increasing strain rates. The temperature effect was studied by means of the reduction factors for the main mechanical properties. Results at high strain rates highlighted also the blue brittleness phenomenon between 400C and 550C. The link between the material and the structural level is a material constitutive law able to take into account the strain rate sensitivity and the thermal softening. The widely used constitutive law proposed by Johnson and Cook was calibrated using the experimental results. A critical review of this material model highlighted a perceptible variation of the thermal softening parameter at different temperatures. Following a fitting approach, a modification of the dimensionless temperature (T*) has been proposed.The structural level was numerically investigated adopting the calibrated material model. Explicit non-linear dynamic analyses of a steel column under fire conditions and followed by an explosion were performed. The commercial code LS-DYNA was used. A method for a realistic multi-hazard approach has been proposed by studying the residual load bearing capacity. The results can be also of great interest to establish the initial conditions that could potentially lead to the onset of progressive collapse in steel framed structures under a combined effect of fire and blast. As expected, the results indicated that the load bearing capacity is influenced by the stand-off distance, the charge size as well as the column boundary conditions. The time of fire loading at which an explosion is triggered is a critical parameter as well

    Risk adjusted mortality after hip replacement surgery: A retrospective study

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    Introduction. Hip replacement (HR) operations are increasing. Short term mortality is an indicator of quality; few studies include risk adjustment models to predict HR outcomes. We evaluated in-hospital and 30-day mortality in hospitalized patients for HR and compared the performance of two risk adjustment algorithms. Materials and methods. A retrospective cohort study on hospital discharge records of patients undergoing HR from 2000 to 2005 in Tuscany Region, Italy, applied All-Patient Refined Diagnosis Related Groups (APR-DRG) and Elixhauser Index (EI) risk adjustment models to predict outcomes. Logistic regression was used to analyse the performance of the two models; C statistic (C) was used to define their discriminating ability. Results. 25 850 hospital discharge records were studied. In-hospital and 30-day crude mortality were 1.3% and 3%, respectively. Female gender was a significant (p < 0.001) protective factor under both models and had the following Odds Ratios (OR): 0.64 for in-hospital and 0.51 for 30-day mortality using APR-DRG and 0.55 and 0.48, respectively, with EI. Among EI comorbidities, heart failure and liver disease were associated with in-hospital (OR 9.29 and 5.60; p < 0.001) and 30-day (OR 6.36 and 3.26; p < 0.001) mortality. Increasing age and APR-DRG risk class were predictive of all the outcomes. Discriminating ability for in-hospital and 30-day mortality was reasonable with EI (C 0.79 and 0.68) and good with APR-DRG (C 0.86 and 0.82). Conclusions. Our study found that gender, age, EI comorbidities and APR-DRG risk of death are predictive factors of in-hospital and 30-day mortality outcomes in patients undergoing HR. At least one risk adjustment algorithm should always be implemented in patient management

    Development of Algorithm for Clinical Management of Sickle Cell Bone Disease: Evidence for a Role of Vertebral Fractures in Patient Follow-up

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    Sickle-cell disease (SCD) is a worldwide distributed hemoglobinopathy, characterized by hemolytic anemia associated with vaso-occlusive events. These result in acute and chronic multiorgan damage. Bone is early involved, leading to long-term disability, chronic pain and fractures. Here, we carried out a retrospective study to evaluate sickle bone disease (SBD) in a cohort of adults with SCD. We assessed bone density, metabolism and turnover. We also evaluated the presence of fractures and the correlation between SCD severity and skeletal manifestations. A total of 71 patients with SCD were analyzed. The mean age of population was 39 \ub1 10 years, 56% of which were females. We found osteoporosis in a range between 7% and 18% with a high incidence of vertebral fractures. LDH and AST were predictive for the severity of vertebral fractures, while bone density was not. Noteworthy, we identified -1.4 Standard Deviations T-score as the cutoff for detecting the presence of fractures in patients with SCD. Collectively our data allowed us to develop an algorithm for the management of SBD, which may be useful in daily clinical practice to early intersect and treat SBD

    A soil fungus confers plant resistance against a phytophagous insect by disrupting the symbiotic role of its gut microbiota

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    Plants generate energy flows through natural food webs, driven by competition for resources among organisms, which are part of a complex network of multitrophic interactions. Here, we demonstrate that the interaction between tomato plants and a phytophagous insect is driven by a hidden interplay between their respective microbiotas. Tomato plants colonized by the soil fungus Trichoderma afroharzianum, a beneficial microorganism widely used in agriculture as a biocontrol agent, negatively affects the development and survival of the lepidopteran pest Spodoptera littoralis by altering the larval gut microbiota and its nutritional support to the host. Indeed, experiments aimed to restore the functional microbial community in the gut allow a complete rescue. Our results shed light on a novel&nbsp;role played by a soil microorganism in the modulation of plant-insect interaction, setting the stage for a more comprehensive analysis of the impact that biocontrol agents may have on ecological sustainability of agricultural systems

    A randomised comparison of deferasirox versus deferoxamine for the treatment of transfusional iron overload in sickle cell disease

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    Deferasirox is a once-daily, oral iron chelator developed for treating transfusional iron overload. Preclinical studies indicated that the kidney was a potential target organ of toxicity. As patients with sickle cell disease often have abnormal baseline renal function, the primary objective of this randomised, open-label, phase II trial was to evaluate the safety and tolerability of deferasirox in comparison with deferoxamine in this population. Assessment of efficacy, as measured by change in liver iron concentration (LIC) using biosusceptometry, was a secondary objective. A total of 195 adult and paediatric patients received deferasirox (n = 132) or deferoxamine (n = 63). Adverse events most commonly associated with deferasirox were mild, including transient nausea, vomiting, diarrhoea, abdominal pain and skin rash. Abnormal laboratory studies with deferasirox were occasionally associated with mild non-progressive increases in serum creatinine and reversible elevations in liver function tests. Discontinuation rates from deferasirox (11·4%) and deferoxamine (11·1%) were similar. Over 1 year, similar dose-dependent LIC reductions were observed with deferasirox and deferoxamine. Once-daily oral deferasirox has acceptable tolerability and appears to have similar efficacy to deferoxamine in reducing iron burden in transfused patients with sickle cell disease

    Relative response of patients with myelodysplastic syndromes and other transfusion-dependent anaemias to deferasirox (ICL670): a 1-yr prospective study

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    Objectives/methods: This 1-yr prospective phase II trial evaluated the efficacy of deferasirox in regularly transfused patients aged 3-81 yrs with myelodysplastic syndromes (MDS; n = 47), Diamond-Blackfan anaemia (DBA; n = 30), other rare anaemias (n = 22) or beta-thalassaemia (n = 85). Dosage was determined by baseline liver iron concentration (LIC). Results: In patients with baseline LIC >= 7 mg Fe/g dry weight, deferasirox initiated at 20 or 30 mg/kg/d produced statistically significant decreases in LIC (P < 0.001); these decreases were greatest in MDS and least in DBA. As chelation efficiency and iron excretion did not differ significantly between disease groups, the differences in LIC changes are consistent with mean transfusional iron intake (least in MDS: 0.28 +/- 0.14 mg/kg/d; greatest in DBA: 0.4 +/- 0.11 mg/kg/d). Overall, LIC changes were dependent on dose (P < 0.001) and transfusional iron intake (P < 0.01), but not statistically different between disease groups. Changes in serum ferritin and LIC were correlated irrespective of disease group (r = 0.59), supporting the potential use of serum ferritin for monitoring deferasirox therapy. Deferasirox had a safety profile compatible with long-term use. There were no disease-specific safety/tolerability effects: the most common adverse events were gastrointestinal disturbances, skin rash and non-progressive serum creatinine increases. Conclusions: Deferasirox is effective for reducing iron burden with a defined, clinically manageable safety profile in patients with various transfusion-dependent anaemias. There were no disease-specific adverse events. Once differences in transfusional iron intake are accounted for, dose-dependent changes in LIC or serum ferritin are similar in MDS and other disease groups

    Spatio-Temporal Features of Visual Exploration in Unilaterally Brain-Damaged Subjects with or without Neglect: Results from a Touchscreen Test

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    Cognitive assessment in a clinical setting is generally made by pencil-and-paper tests, while computer-based tests enable the measurement and the extraction of additional performance indexes. Previous studies have demonstrated that in a research context exploration deficits occur also in patients without evidence of unilateral neglect at pencil-and-paper tests. The objective of this study is to apply a touchscreen-based cancellation test, feasible also in a clinical context, to large groups of control subjects and unilaterally brain-damaged patients, with and without unilateral spatial neglect (USN), in order to assess disturbances of the exploratory skills. A computerized cancellation test on a touchscreen interface was used for assessing the performance of 119 neurologically unimpaired control subjects and 193 patients with unilateral right or left hemispheric brain damage, either with or without USN. A set of performance indexes were defined including Latency, Proximity, Crossings and their spatial lateral gradients, and Preferred Search Direction. Classic outcome scores were computed as well. Results show statistically significant differences among groups (assumed p<0.05). Right-brain-damaged patients with USN were significantly slower (median latency per detected item was 1.18 s) and less efficient (about 13 search-path crossings) in the search than controls (median latency 0.64 s; about 3 crossings). Their preferred search direction (53.6% downward, 36.7% leftward) was different from the one in control patients (88.2% downward, 2.1% leftward). Right-brain-damaged patients without USN showed a significantly abnormal behavior (median latency 0.84 s, about 5 crossings, 83.3% downward and 9.1% leftward direction) situated half way between controls and right-brain-damaged patients with USN. Left-brain-damaged patients without USN were significantly slower and less efficient than controls (latency 1.19 s, about 7 crossings), preserving a normal preferred search direction (93.7% downward). Therefore, the proposed touchscreen-based assessment had evidenced disorders in spatial exploration also in patients without clinically diagnosed USN

    Competence Centre ICDI per Open Science, FAIR, ed EOSC - Mission, Strategia e piano d'azione

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    This document presents the mission and strategy of the Italian Competence Centre on Open Science, FAIR, and EOSC. The Competence Centre is an initiative born within the Italian Computing and Data Infrastructure (ICDI), a forum created by representatives of major Italian Research Infrastructures and e-Infrastructures, with the aim of promoting sinergies at the national level, and optimising the Italian participation to European and global challenges in this field, including the European Open Science Cloud (EOSC), the European Data Infrastructure (EDI) and HPC. This working paper depicts the mission and objectives of the ICDI Competence Centre, a network of experts with various skills and competences that are supporting the national stakeholders on topics related to Open Science, FAIR principles application and participation to the EOSC. The different actors and roles are described in the document as well as the activities and services offered, and the added value each stakeholder can find the in Competence Centre. The tools and services provided, in particular the concept for the portal, though which the Centre will connect to the national landscape and users, are also presented

    Planck 2013 results. XXVII. Doppler boosting of the CMB : Eppur si muove

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    Planck 2013 results. XXI. Power spectrum and high-order statistics of the Planck all-sky Compton parameter map

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