76 research outputs found

    Updated management of malignant biliary tract tumors: an illustrative review

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    The management of malignant biliary tumors (MBTs) is complex and requires a multidisciplinary approach. Guidelines and methods of staging for biliary tumors have recently been released by main international societies, altering the clinical and radiologic approach to this pathologic condition. The aim of the present review is to detail the updated role of imaging in preoperative staging and follow-up and to illustrate clinical/therapeutic pathways. In addition, future perspectives on imaging and targeted/embolization therapies are outlined

    Anticoagulation in Peripheral Artery Disease: Are We There Yet?

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    Thromboembolism in patients with peripheral artery disease (PAD) represents a common cause of morbidity and mortality. In this article, the authors analyse the use of anticoagulants for patients with PAD. Anticoagulants have been used to reduce the risk of venous thromboembolism, but have recently been applied to the arterial circulation. Heparins were introduced to reduce short-term major adverse limb events in patients undergoing arterial revascularisation. Low molecular weight heparins have allowed easier management and carry a lower risk of bleeding than unfractioned heparin. Vitamin K anticoagulants have been tested in trials that included patients with PAD, showing an increased risk of bleeding when compared with aspirin alone, but longer patency rates for venous surgical bypass, although the evidence remains weak. Those anticoagulants are currently recommended only in patients with PAD who need anticoagulation for other diseases. Direct oral anticoagulants have only recently been investigated for use in patients with PAD. Promising results from low dose rivaroxaban plus aspirin have been recently outlined by a randomised controlled trial and supported by international guidelines

    Non-vascular interventional procedures: effective dose to patient and equivalent dose to abdominal organs by means of dicom images and Monte Carlo simulation

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    This study evaluates X-ray exposure in patient undergoing abdominal extra-vascular interventional procedures by means of Digital Imaging and COmmunications in Medicine (DICOM) image headers and Monte Carlo simulation. The main aim was to assess the effective and equivalent doses, under the hypothesis of their correlation with the dose area product (DAP) measured during each examination. This allows to collect dosimetric information about each patient and to evaluate associated risks without resorting to in vivo dosimetry. The dose calculation was performed in 79 procedures through the Monte Carlo simulator PCXMC (A PC-based Monte Carlo program for calculating patient doses in medical X-ray examinations), by using the real geometrical and dosimetric irradiation conditions, automatically extracted from DICOM headers. The DAP measurements were also validated by using thermoluminescent dosimeters on an anthropomorphic phantom. The expected linear correlation between effective doses and DAP was confirmed with an R(2) of 0.974. Moreover, in order to easily calculate patient doses, conversion coefficients that relate equivalent doses to measurable quantities, such as DAP, were obtained

    Optimal control and performance of photovoltachromic switchable glazing for building integration in temperate climates

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    The development of adaptive building envelope technologies, and particularly of switchable glazing, can make significant contributions to decarbonisation targets. It is therefore essential to quantify their effect on building energy use and indoor environmental quality when integrated into buildings. The evaluation of their performance presents new challenges when compared to conventional “static” building envelope systems, as they require design and control aspects to be evaluated together, which are also mutually interrelated across thermal and visual physical domains. This paper addresses these challenges by presenting a novel simulation framework for the performance evaluation of responsive building envelope technologies and, particularly, of switchable glazing. This is achieved by integrating a building energy simulation tool and a lighting simulation one, in a control optimisation framework to simulate advanced control of adaptive building envelopes. The performance of a photovoltachromic glazing is evaluated according to building energy use, Useful Daylight Illuminance, glare risk and load profile matching indicators for a sun oriented office building in different temperate climates. The original architecture of photovoltachromic cell provides an automatic control of its transparency as a function of incoming solar irradiance. However, to fully explore the building integration potential of photovoltachromic technology, different control strategies are evaluated, from passive and simple rule based controls, to optimised rule based and predictive controls. The results show that the control strategy has a significant impact on the performance of the photovoltachromic switchable glazing, and of switchable glazing technologies in general. More specifically, simpler control strategies are generally unable to optimise contrasting requirements, while more advanced ones can increase energy saving potential without compromising visual comfort. In cooling dominated scenarios reactive control can be as effective as predictive for a switchable glazing, differently than heating dominated scenarios where predictive control strategies yield higher energy saving potential. Introducing glare as a control parameter can significantly decrease the energy efficiency of some control strategies, especially in heating dominated climates.This work was conducted as part of a PhD research sponsored by UK EPSRC and Wintech Ltd. The authors acknowledge the support of the COST Action TU1403 – Adaptive Facades Network (www.adaptivefacade.eu) and the University of Sydney (IPDF fund). The experimental data used as an input in this work were partially supported by Regione PUGLIA (APQ Reti di Laboratorio, project “PHOEBUS” cod. 31) and by Italian Minister for Education and Research which funded the R&D program “MAAT” (PON02_00563_3316357 − CUP B31C12001230005). The devices were fabricated at the Center for Biomolecular Nanotechnologies of Istituto Italiano di Tecnologia and characterized in the laboratories of CNR-Nano in Lecce. The contribution of the fourth author to the work reported in this paper was supported by the Australian Research Council through its Future Fellowship scheme (FT140100130).This is the final version of the article. It first appeared from Elsevier at http://dx.doi.org/10.1016/j.apenergy.2016.06.107

    Room temperature Bloch surface wave polaritons

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    Polaritons are hybrid light-matter quasi-particles that have gathered a significant attention for their capability to show room temperature and out-of-equilibrium Bose-Einstein condensation. More recently, a novel class of ultrafast optical devices have been realized by using flows of polariton fluids, such as switches, interferometers and logical gates. However, polariton lifetimes and propagation distance are strongly limited by photon losses and accessible in-plane momenta in usual microcavity samples. In this work, we show experimental evidence of the formation of room temperature propagating polariton states arising from the strong coupling between organic excitons and a Bloch surface wave. This result, which was only recently predicted, paves the way for the realization of polariton devices that could allow lossless propagation up to macroscopic distances

    Multifunctional bioinspired sol-gel coatings for architectural glasses

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    Although several multinational companies have recently released products incorporating bioinspired functional coatings, their practical integration in building envelopes is still an open issue. High production costs associated to the existing vacuum deposition technologies, as well as the difficulties in extending the number of functions achievable by a single coating, represent to date the main limitations to their diffusion on a large scale. This review summarizes the key topics in the field of functional coatings for architectural glasses, focusing in particular on the potential applications of sol-gel based antireflective and self-cleaning coatings, that have received a tremendous attention in the last years. It provides an overview of the recent research efforts aimed to improve their properties and to extend their range of applicability. The bioinspired principles, upon which such coatings are based, are also described and are related to the chemical and morphological properties of such surfaces. (C) 2009 Elsevier Ltd. All rights reserved

    Ultrafast flow of interacting organic polaritons

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    The strong-coupling of an excitonic transition with an electromagnetic mode results in composite quasi-particles called exciton-polaritons, which have been shown to combine the best properties of their bare components in semiconductor microcavities. However, the physics and applications of polariton flows in organic materials and at room temperature are still unexplored because of the poor photon confinement in such structures. Here we demonstrate that polaritons formed by the hybridization of organic excitons with a Bloch Surface Wave are able to propagate for hundreds of microns showing remarkable third-order nonlinear interactions upon high injection density. These findings pave the way for the studies of organic nonlinear light-matter fluxes and for a technological promising route of dissipation-less on-chip polariton devices working at room temperature.Comment: Improved version with polariton-polariton interactions. 13 pages, 4 figures, supporting 6 pages, 6 figure

    Highly efficient smart photovoltachromic devices with tailored electrolyte composition

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    Driven by the tremendous opportunities offered by dye solar cells technology in terms of building integration, a new generation of smart multifunctional photoelectrochemical cells has the potential to attract the interest of a rapidly growing number of research institutions and industrial companies. Photovoltachromic devices are capable to produce a smart modulation of the optical transmittance and, at the same time, to generate electrical power by means of solar energy conversion. In this work, a specifically designed bifunctional counterelectrode has been realized by depositing a C-shaped platinum frame which bounds a square region occupied by a tungsten oxide (WO3) film onto a transparent conductive substrate. These two regions have been electrically separated to make possible distinct operations on one or both of the available circuits. Such an unconventional counterelectrode makes it possible to achieve a twofold outcome: a smart and fast-responsive control of the optical transmittance and a relatively high photovoltaic conversion efficiency. In particular we investigated the effect of the electrolyte composition on both photoelectrochromic and photovoltaic performances of such devices by systematically tuning the iodide content in the electrolyte. The best result was obtained by filling the cell with an iodine concentration of 0.005 M: a coloration efficiency of 61.10 cm(2) C-1 at a wavelength of 780 nm and, at the same time, a photovoltaic conversion efficiency of 6.55% have been reported

    Durable superhydrophobic and antireflective surfaces by trimethylsilanized silica nanoparticles-based sol-gel processing.

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    We present a robust and cost-effective coating method to fabricate long-term durable superhydrophobic, and-simultaneously-antireflective surfaces by a double-layer coating comprising trimethylsiloxane (TMS) surface-functionalized silica nanoparticles partially embedded into an organosilica binder matrix produced through a sol-gel process. A dense and homogeneous organosilica gel layer was First coated onto a glass substrate, and then, a trimethylsilanized nanospheres-based superhydrophobic layer was deposited onto it. After thermal curing, the two layers turned into a monolithic film, and the hydrophobic nanoparticles were permanently fixed to the glass substrate. Such treated surfaces showed a tremendous water repellency (contact angle = 168 degrees) and stable self-cleaning effect during 2000 h of outdoor exposure. Besides this, nanotextured topology generated by the self-assembled nanoparticles-based top layer produced a fair antireflection effect consisting of more than a 3% increase in optical transmittance
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