1,779 research outputs found

    Strong-field approximation for harmonic generation in diatomic molecules

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    The generation of high-order harmonics in diatomic molecules is investigated within the framework of the strong-field approximation. We show that the conventional saddle-point approximation is not suitable for large internuclear distances. An adapted saddle-point method that takes into account the molecular structure is presented. We analyze the predictions for the harmonic-generation spectra in both the velocity and the length gauge. At large internuclear separations, we compare the resulting cutoffs with the predictions of the simple-man's model. Good agreement is obtained only by using the adapted saddle-point method combined with the velocity gauge.Comment: 24 pages, 7 figure

    Familial Mediterranean Fever: An unusual cause of liver disease

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    Background Familial Mediterranean Fever is an autoinflammatory disease typically expressed with recurrent attacks of fever, serositis, aphthous stomatitis, rash. Only a few reports describe the association with hepatic involvement. Case presentation We describe the clinical case of a child affected, since the age of 1 year, by recurrent fever, aphthous stomatitis, rash, arthralgia, associated with abdominal pain, vomiting, lymphadenopathy. The diagnosis of Familial Mediterranean Fever was confirmed by the genetic study of MEFV gene; the homozygous mutation M694 V in exon was documented. A partial control of attacks was obtained with colchicine. The child continued to manifest only recurrent episodes of abdominal pain without fever, however serum amyloid A persisted high, in association with enhanced levels of CRP, AST and ALT (1.5 x n.v.). The dosage of colchicine was increased step by step and the patient achieved a better control of symptoms and biochemical parameters. However, the patient frequently needed an increase in the dose of colchicine, suggesting the possible usefulness of anti-interleukin-1 beta treatment. Conclusions The unusual presentation of Familial Mediterranean Fever with liver disease suggests the role of inflammasome in hepatic inflammation. Colchicine controls systemic inflammation in most of the patients; however, subclinical inflammation can persist in some of them and can manifest with increased levels of CRP, ESR, serum amyloid A also in attack-free intervals

    Dynamic reconfiguration of electrical connections for partially shaded PV modules: Technical and economical performances of an Arduino-based prototype

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    The partial shading phenomenon is a well known problem of photovoltaic plants. Partial shading leads to undesirable effects such the electrical mismatch, the generation of hot spots, and generally the decrease of production of electric energy. To mitigate the last effect, a dynamic reconfiguration of the electrical connections between modules was taken into account. In this paper, starting from an already developed system for a small-scale photovoltaic plant reconfiguration, the study of the economical benefits of the employment of a reconfigurator are traced. Five different incentive policies of diverse Countries have been considered to evaluate the increase of Net Present Value of system with and without a reconfigurator

    RELAP5-3D thermal hydraulic analysis of the target cooling system in the SPES experimental facility

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    The SPES (Selective Production of Exotic Species) experimental facility, under construction at the Italian National Institute of Nuclear Physics (INFN) Laboratories of Legnaro, Italy, is a second generation Isotope Separation On Line (ISOL) plant for advanced nuclear physic studies. The UCx target-ion source system works at temperature of about 2273 K, producing a high level of radiation (10^5 Sv/h), for this reason a careful risk analysis for the target chamber is among the major safety issues. In this paper, the obtained results of thermofluid-dynamics simulations of accidental transients in the SPES target cooling system are reported. The analysis, performed by using the RELAP5-3D 2.4.2 qualified thermal-hydraulic system code, proves good safety performance of this system during different accidental conditions

    RELAP5 simulation of two-phase flow experiments in vertical helical tubes

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    In the framework of the studies concerning the thermalfluid dynamic phenomena in helicoidal pipes of the innovative nuclear reactor IRIS steam generators, the Department of Nuclear Engineering of the University of Palermo in collaboration with the Politecnico di Torino Department of Energetics has been engaged in a work aimed to adapt, by implementing new suitable models, RELAP5/mod3.2.2β code to simulate the thermalfluid-dynamics and geometries such as the ones involved in helicoidal pipes. In fact this code is based on one-dimensional thermal-hydraulic relationships and presents limitations to model complicated geometry such as helicoidal pipes. Therefore the code was improved with additional correlations that are valid for two-phase flow and allow to overcome the drawbacks. The validation work of the models that were added is based on the experimental data carried out at the Politecnico di Torino Department of Energetics. In this paper it will be shown that the so modified RELAP5 code allows to represent adequately the experimental data

    Experimental study on B-spline-based modulation schemes applied in multilevel inverters for electric drive applications

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    This work presents the design, simulation, and experimental validation of new B-Spline-based modulation techniques applied to a Multilevel Power Inverter (MPI), particularly focusing the attention on the harmonic content of the output voltages of the inverter. Simulation and experimental results are proposed and discussed, mainly describing the potential benefits, such as the increase of the multi-level operation of the converter, and drawbacks (low-order harmonics) related to the adoption of B-Spline functions for multilevel inverters applied in the field of electrical drives

    EGFR inhibition in NSCLC: New findings\u2026. and opened questions?

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    The targeted inhibition of epidermal growth factor receptor (EGFR) has represented a milestone in the treatment of lung cancer. Several studies convincingly and consistently demonstrated a significant superiority of EGFR-TKIs over standard platinum-chemotherapy in EGFR-mutated NSCLC patients, leading to the sequential approval of gefitinib, erlotinib and afatinib as new standard first-line clinical treatment. To date we are witnessing a second revolution in the management of EGFR-positive NSCLC thanks to the development of new treatment strategies aiming to overcome acquired resistance to TKIs and ultimately improve patients\u2019 outcomes. In this review we summarize the most important recent findings regarding EGFR-inhibition in NSCLC, highlighting the current unsolved questions on the selection of the best TKI in first-line, which therapy can be combined with upfront EGFR-TKIs, how to overcome acquired resistance, and which are the clinical applications of liquid biopsy

    Immunohistochemical/histochemical double staining method in the study of columnar metaplasia of the oesophagus

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    Intestinal metaplasia in Barrett\u2019s oesopha- gus (BO) represents an important risk factor for oesophageal adenocarcinoma. Instead, few and controversial data are reported about the progression risk of columnar-lined oesophagus without intestinal metaplasia (CLO), posing an issue about its clinical management. The aim was to evaluate if some immunophenotyp- ic changes were present in CLO independently of the presence of the goblet cells. We studied a series of oesophageal biopsies from patients with endoscopic finding of columnar metapla- sia, by performing some immunohistochemical stainings (CK7, p53, AuroraA) combined with histochemistry (Alcian-blue and Alcian/PAS), with the aim of simultaneously assess the his- tochemical features in cells that shows an aber- rant expression of such antigens. We evidenced a cytoplasmic expression of CK7 and a nuclear expression of Aurora A and p53, both in goblet cells of BO and in non-goblet cells of CLO, some of which showing mild dysplasia. These find- ings suggest that some immunophenotypic changes are present in CLO and they can pre- cede the appearance of the goblet cells or can be present independently of them, confirming the conception of BO as the condition charac- terized by any extention of columnar epitheli- um. This is the first study in which a combined immunohistochemical/histochemical method has been applied to Barrett pathology
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