234 research outputs found

    Gallstone ileus treated with non-surgical conservative methods: a case report

    Get PDF
    INTRODUCTION: The preoperative diagnosis of gallstone ileus is challenging due to the variability of its presentation, often resulting in late diagnosis. Controversy remains regarding the management of gallstone ileus; surgery is the standard treatment, but also less invasive approaches have proven to be successful. We present an unusual case of gallstone ileus and its conservative treatment. CASE PRESENTATION: We describe the case of a 49-year-old Caucasian woman with a bowel sub-occlusion, treated conservatively. The imaging technique (plain abdominal X-ray and computed tomography scan) led to a diagnosis of gallstones ileus. A surgical intervention was not performed. Instead, she underwent extracorporeal shock-wave lithotripsy to fragment the stones, mechanical intestinal dilatation for ileocolic stenosis and endoscopic removal of the gallstone. The presence of an apricot shell contributed to the bowel occlusion and was removed. The intervention was successful and without complications. CONCLUSIONS: Given the variability of the gallstone ileus presentation, surgery could not be the only treatment for our patient. In our case report, we show that colonoscopy could be a non-invasive approach that allows for diagnosis and treatment at the same time. The available data do not show a higher rate of recurrent biliary disease in cases where this method has been used, therefore in select patients, a conservative treatment could be an effective solution

    Shock loss measurements in non-ideal supersonic flows of organic vapors

    Get PDF
    This paper presents the first ever direct measurements of total pressure losses across shocks in supersonic flows of organic vapors in non-ideal conditions, so in the thermodynamic region close to the liquid-vapor saturation curve and the critical point where the ideal gas law is not applicable. Experiments were carried out with fluid siloxane MM (hexamethyldisiloxane, C6H18OSi2), commonly employed in medium-/high-temperature organic Rankine cycles (ORCs), in the Test Rig for Organic VApors (TROVA), a blowdown wind tunnel at the Laboratory of Compressible fluid dynamics for Renewable Energy Applications (CREA lab) of Politecnico di Milano. A total pressure probe was inserted in superheated MM vapor flow at Mach number similar to 1.5 with total conditions in the range 215 - 230 degrees C and 2 - 12 bar at varying levels of non-ideality, with a compressibility factor evaluated at total conditions between Z(T) = 0.68 - 0.98. These operating conditions are representative of the first-stage stator of ORC turbines. Measured shock losses were compared with those calculated from pre-shock quantities by solving conservation equations across a normal shock, with differences always below 2% attesting a satisfactory reliability of the implemented experimental procedure. An in-depth analysis was then carried out, highlighting the direct effects of non-ideality on shock intensity. Even at the mildly non-ideal conditions with Z(T) greater than or similar to 0.70 considered here, non-ideality was responsible for a significantly stronger shock compared to the ideal gas limit at same pre-shock Mach number, with differences as large as 6%.[GRAPHICS]

    Experimental and numerical analysis of supersonic blade profiles developed for highly loaded impulse type steam turbine stages

    Get PDF
    The paper describes the results of a numerical and experimental research program addressing the aerodynamic investigation on the performance of blade profiles specifically developed for application in highly loaded impulse type turbine stages. The industrial requirements driving toward the adoption of highly loaded stage solutions are presented, along with an estimation of the profiles operating parameters. Two stator vanes and one rotor blade profile have been developed and extensively tested by means of flow field measurements and schlieren visualization in a transonic blow-down wind tunnel for linear cascades. Experimental results for the relevant operating conditions are presented, providing validation data for the CFD model used for blade design and evidencing that the main goals of the design optimization procedure have been achieved

    A systematic review of the literature on the role of tracheostomy in COVID-19 patients

    Get PDF
    – The Coronavirus Disease 2019 (COVID-19) is a viral infection caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), which emerged in East Asia and spread around the world from December 2019. The most severe stage of COVID-19 pathology is characterized by respiratory distress requiring intubation. In specific cases, tracheostomy is indicated to ensure the safety of the procedure. The aim of our study was to analyze the scientific literature identifying the indications for tracheostomy and safety precautions to reduce contamination. We analyzed the literature from February 2003 to April 2020, including papers on pandemics of other coronaviruses, such As Severe Acute Respiratory Syndrome Coronavirus 1 and Middle East Respiratory Syndrome Coronavirus, to obtain a variety of relevant information. We focused on indications for tracheostomy in patients affected by COVID-19 or related viruses and the measures adopted to perform a safe procedure. We included 35 papers, of which 24 (68.57%) discussed guidelines for tracheostomy indications. All 35 studies discussed the procedures for performing tracheostomy safely. Data obtained indicated that the authors generally agreed on safety measures but expressed different opinions about indications. Therefore, we provided guidelines addressing safety recommendations. After the pandemic has been resolved, we plan to conduct an international retrospective study to identify the criteria for tracheostomy indications

    Structure and mechanism of acetolactate decarboxylase

    Get PDF
    Acetolactate decarboxylase catalyzes the conversion of both enantiomers of acetolactate to the (R)-enantiomer of acetoin, via a mechanism that has been shown to involve a prior rearrangement of the non-natural (R)-enantiomer substrate to the natural (S)-enantiomer. In this paper, a series of crystal structures of ALDC complex with designed transition state mimics are reported. These structures, coupled with inhibition studies and site-directed mutagenesis provide an improved understanding of the molecular processes involved in the stereoselective decarboxylation/protonation events. A mechanism for the transformation of each enantiomer of acetolactate is proposed

    The new communication network for an internet of everything based security/safety/general management/visitor's services for the Papal Basilica and Sacred Convent of Saint Francis in Assisi, Italy

    Get PDF
    © 2017 IEEE.The Papal Basilica and the Sacred Convent of St. Francis in Assisi, Italy together represent a unique and specific cultural heritage site where the mortal remains of St. Francis have been housed since 1230 AD. Millions of pilgrims and visitors from all over the world visit this site each year. In 2000 AD, together with other Franciscan sites in the surrounding area, it achieved UNESCO World Heritage status. Unique and complex cultural heritage sites, such as this, require a significant effort to ensure visitor security and safety. Along with such needs are cultural heritage preservation and protection as well as accessibility for visitors, with particular reference to visitors with disabilities, and for personnel normally present for site management, including the Friar's community. These aims can be achieved using integrated systems and innovative technologies, such as Internet of Everything (IoE) which can connect people, things (mobile terminals, smart sensors, devices, actuators; wearable devices; etc.), data/information/knowledge and particular processes. The purpose of this paper is to illustrate the methodology and show the results obtained from the study and the design of a new communication network for Internet of Everything based security/safety/general management and visitors' services of the Papal Basilica and Sacred Convent of Saint Francis in Assisi

    A Gα-Stimulated RapGEF Is a Receptor-Proximal Regulator of Dictyostelium Chemotaxis

    Get PDF
    Chemotaxis, or directional movement toward extracellular chemical gradients, is an important property of cells that is mediated through G-protein-coupled receptors (GPCRs). Although many chemotaxis pathways downstream of Gβγ have been identified, few Gα effectors are known. Gα effectors are of particular importance because they allow the cell to distinguish signals downstream of distinct chemoattractant GPCRs. Here we identify GflB, a Gα2 binding partner that directly couples the Dictyostelium cyclic AMP GPCR to Rap1. GflB localizes to the leading edge and functions as a Gα-stimulated, Rap1-specific guanine nucleotide exchange factor required to balance Ras and Rap signaling. The kinetics of GflB translocation are fine-tuned by GSK-3 phosphorylation. Cells lacking GflB display impaired Rap1/Ras signaling and actin and myosin dynamics, resulting in defective chemotaxis. Our observations demonstrate that GflB is an essential upstream regulator of chemoattractant-mediated cell polarity and cytoskeletal reorganization functioning to directly link Gα activation to monomeric G-protein signaling
    corecore