225 research outputs found

    Detailed neutronic study of the power evolution for the European Sodium Fast Reactor during a positive insertion of reactivity

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    Abstract The new reactor concepts proposed in the Generation IV International Forum require the development and validation of new components and new materials. Inside the Collaborative Project on the European Sodium Fast Reactor, several accidental scenario have been studied. Nevertheless, none of them coped with mechanical safety assessment of the fuel cladding under accidental conditions. Among the accidental conditions considered, there is the unprotected transient of overpower (UTOP), due to the insertion, at the end of the first fuel cycle, of a positive reactivity into the reactor core as a consequence of the unexpected runaway of one control rod. The goal of the study was the search for a detailed distribution of the fission power, in the radial and axial directions, within the power peaked fuel pin under the above accidental conditions. Results show that after the control rod ejection an increase from 658 W/cm 3 to 894 W/cm 3 , i.e. of some 36%, is expected for the power peaked fuel pin. This information will represent the base to investigate, in a future work, the fuel cladding safety margin

    Original immunophenotype of blood endothelial progenitor cells and microparticles in patients with isolated arterial erectile dysfunction and late onset hypogonadism: effects of androgen replacement therapy.

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    Blood endothelial progenitor cells (EPCs) and endothelial microparticles (EMPs) have been proposed as markers of endothelial dysfunction. Aim of this study was to evaluate an original immunophenotype of EPCs and EMPs in patients with isolated arterial erectile dysfunction (ED) and late onset hypogonadism (LOH) before and after androgen replacement therapy.Fifty patients (50-64 years) with ED and LOH were selected. EPC (CD45(neg)/CD34(pos)/CD144(pos)) and EMP (CD45(neg)/CD34(neg)/CD144(pos)) blood concentrations were evaluated by flow cytometry. Thirty patients received androgen replacement therapy (TostrexÂź ProStrakan) for 6 months (group A), other 20 patients not received androgen therapy for the contraindications in their clinical history (group B).After 6 months, group B showed IIEF-5 score, peak systolic velocity and acceleration time significantly worse than group A; in addition EPCs and EMPs were significantly higher in group B compared to group A.Patients with isolated arterial ED and LOH not treated with androgen therapy showed worst vascular parameters measured by penile Doppler and higher EPCs and EMPs compared to treated hypogonadal patients, hence, LOH appears to be an additional vascular risk factor, and these markers may be considered as predictors of cavernous artery disease. Finally, androgen therapy improves endothelial dysfunction

    Efficacy of Infection Control Interventions in Reducing the Spread of Multidrug-Resistant Organisms in the Hospital Setting

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    Multidrug-resistant organisms (MDRO) continue to spread in hospitals globally, but the population-level impact of recommended preventive strategies and the relative benefit of individual strategies targeting all MDRO in the hospital setting are unclear. To explore the dynamics of MDRO transmission in the hospital, we develop a model extending data from clinical individual-level studies to quantify the impact of hand hygiene, contact precautions, reducing antimicrobial exposure and screening surveillance cultures in decreasing the prevalence of MDRO colonization and infection. The effect of an ongoing increase in the influx of patients colonized with MDRO into the hospital setting is also quantified. We find that most recommended strategies have substantial effect in decreasing the prevalence of MDRO over time. However, screening for asymptomatic MDRO colonization among patients who are not receiving antimicrobials is of minimal value in reducing the spread of MDRO

    neuroimaging changes in menkes disease part 2

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    SUMMARY: This is the second part of a retrospective and review MR imaging study aiming to define the frequency rate, timing, imaging features, and evolution of gray matter changes in Menkes disease, a rare multisystem X-linked disorder of copper metabolism characterized by early, severe, and progressive neurologic involvement. According to our analysis, neurodegenerative changes and focal basal ganglia lesions already appear in the early phases of the disease. Subdural collections are less common than generally thought; however, their presence remains important because they might challenge the differential diagnosis with child abuse and might precipitate the clinical deterioration. Anecdotal findings in our large sample seem to provide interesting clues about the protean mechanisms of brain injury in this rare disease and further highlight the broad spectrum of MR imaging findings that might be expected while imaging a child with the suspicion of or a known diagnosis of Menkes disease
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