400 research outputs found

    Symmetric Vlasov-type antenna for High Power Microwave applications

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    We present a novel Vlasov-type antenna operating at 2.5 GHz and composed of a circular waveguide with a double bevel-cut. Simulation results show that the proposed antenna is capable of providing a wider emission angle if compared to standard Vlasov configurations, while still maintaining an adequate gain level. For this reason, it could be of interest for those High-Power Microwave (HPM) applications in which a larger area need to be covered by the EM field

    Waveguiding and nonlinear optical properties of three-dimensional waveguides in LiTaO<inf>3</inf> written by high-repetition rate ultrafast laser

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    We report the fabrication of waveguides in lithium tantalate using a 250 kHz high-repetition rate ultrafast laser at 771 nm and the characterization of the resulting laser induced structure with second harmonic microscopy. Waveguides operating at the 1.5 μm telecommunication wavelength were formed above and below the focal volume using pulse energies ranging from 100 to 1.6 J and translation speeds from 100 μms to 5 mms. The second harmonic microscopy reveals no degradation of the electro-optic coefficient in the guiding region above the focal volume. © 2008 American Institute of Physics

    Perception of the role of food and dietary modifications in patients with inflammatory bowel disease: Impact on lifestyle

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    Background: Diet has a relevant role in triggering symptoms in inflammatory bowel disease (IBD) from the patients’ perspective, but there is gap the between patients’ and doctors’ perceptions. Few studies have addressed this topic. The aim of this study was to evaluate food habits and nutrition knowledge in a homogeneous cohort of patients with IBD from southern Italy. Methods: 167 consecutive patients with IBD were recruited. The survey was based on the administration of a semi-structured questionnaire assessing demographics, disease features, dietary behavior, and food intolerance. Results: The majority of patients did not consider food a cause of their disease. However more than 80% changed their diet after the diagnosis and most report an improvement in symptoms. Spiced and seasoned foods, dairy products, vegetables, and fruit were often avoided. A dairy-free diet was adopted by 33.7%. Food choices were based on self-experience and not on medical counselling. Dietary modifications deeply impact on lifestyle. Conclusions: Most of the patients with IBD set diet and lifestyle on self-experience and give up many foods. This has an impact on psychosocial functioning and can lead to nutritional deficiencies. High quality studies are warranted to assess evidence-based dietary strategies and develop patient-targeted dietary recommendations

    A COMPARISON OF METHODS FOR SELECTING PREFERRED SOLUTIONS IN MULTIOBJECTIVE DECISION MAKING

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    ISBN : 978-94-91216-77-0In multiobjective optimization problems, the identified Pareto Frontiers and Sets often contain too many solutions, which make it difficult for the decision maker to select a preferred alternative. To facilitate the selection task, decision making support tools can be used in different instances of the multiobjective optimization search to introduce preferences on the objectives or to give a condensed representation of the solutions on the Pareto Frontier, so as to offer to the decision maker a manageable picture of the solution alternatives. This paper presents a comparison of some a priori and a posteriori decision making support methods, aimed at aiding the decision maker in the selection of the preferred solutions. The considered methods are compared with respect to their application to a case study concerning the optimization of the test intervals of the components of a safety system of a nuclear power plant. The engine for the multiobjective optimization search is based on genetic algorithms

    Ganetespib in combination with pemetrexed-platinum chemotherapy in patients with pleural Mesothelioma (MESO-02): A phase Ib trial

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    Purpose: Ganetespib, a highly potent, small-molecule Heatshock protein 90 inhibitor, has potential efficacy in malignant pleural mesothelioma (MPM) via activity on critical survival pathways and known synergies with antifolates and platinum chemotherapy. We conducted a dose-escalation study to identify the maximum tolerated dose (MTD) of ganetespib in patients with chemotherapy-naïve MPM. Patients and Methods: MESO-02 (ClinicalTrials.gov: NCT01590160) was a nonrandomized, multicenter, phase Ib trial of 3-weekly ganetespib (100 mg/m2, 150 mg/m2, 200 mg/m2; days 1 and 15) with pemetrexed (500 mg/m2; day 1) and cisplatin (75 mg/m2; day 1) or carboplatin (area under concentration–time curve 5; day 1) in patients with MPM. Dose escalation was performed using the 3 + 3 design (cisplatin) and accelerated titration design (carboplatin). Secondary endpoints included best response, progression-free survival (PFS), and pharmacogenomic analyses. Results: Of 27 patients enrolled (cisplatin, n = 16; carboplatin, n = 11), 3 experienced dose-limiting toxicities: grade 3 nausea (cisplatin, n = 1; carboplatin, n = 1) and grade 2 infusion-related reaction (carboplatin, n = 1). Ganetespib's MTD was 200 mg/m2. Partial response was observed in 14 of 27 patients (52%; 61% in 23 response-evaluable patients) and 13 of 21 (62%) with epithelioid histology. At the MTD, 10 of 18 patients (56%) had partial response, 15 of 18 (83%) had disease control, and median PFS was 6.3 months (95% CI, 5.0–10.0). One responder exhibited disease control beyond 50 months. Global loss of heterozygosity was associated with shorter time to progression (HR 1.12; 95% CI, 1.02–1.24; P = 0.018). Conclusions: Ganetespib can be combined safely with pemetrexed and platinum chemotherapy to treat patients with MPM. This class of agent should be investigated in larger randomized studies

    Wideband THz time domain spectroscopy based on optical rectification and electro-optic sampling

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    We present an analytical model describing the full electromagnetic propagation in a THz time-domain spectroscopy (THz-TDS) system, from the THz pulses via Optical Rectification to the detection via Electro Optic-Sampling. While several investigations deal singularly with the many elements that constitute a THz-TDS, in our work we pay particular attention to the modelling of the time-frequency behaviour of all the stages which compose the experimental set-up. Therefore, our model considers the following main aspects: (i) pump beam focusing into the generation crystal; (ii) phase-matching inside both the generation and detection crystals; (iii) chromatic dispersion and absorption inside the crystals; (iv) Fabry-Perot effect; (v) diffraction outside, i.e. along the propagation, (vi) focalization and overlapping between THz and probe beams, (vii) electro-optic sampling. In order to validate our model, we report on the comparison between the simulations and the experimental data obtained from the same set-up, showing their good agreement
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