2,305 research outputs found

    Neurological Screening in Elderly Liver Transplantation Candidates: A Single Center Experience

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    Background: Cerebral small vessels disease (cSVD) is an age-related disorder and risk factor for stroke and cognitive/motor impairments. Neurological complications (NCs) are among the causes of adverse outcomes in older liver transplant recipients. This study sought to determine whether cSVD predicts acute NCs in over 65-year-old liver transplant patients. Methods: Data were collected, from a retrospective medical chart review, of 22 deceased donor liver transplant recipients aged 65 years or older with a pre-operative brain magnetic resonance imaging (MRI). We used the Fazekas score (0–3) as a quantitative measurement of the vascular lesion load seen in the MRI. We analyzed all post-operative acute NCs occurring during the hospital stay and any other non-NC. Results: cSVD was recognized in all patients. Neurological complications (NCs) occurred in 18.1% of patients with toxic-metabolic encephalopathy the most frequent diagnosis (13.64%). More severe cSVD was associated with seizures (p = 0.0362), longer hospital stay (p 0.0299), and disability (p 0.0134). In our elderly cohort, hepatic encephalopathy (HE) (p 0.0287) and ascites (p 0.0270) were predictors of NCs after liver transplantation. Ascites and/or variceal bleeding and severity of liver disease were associated with adverse post-operative outcomes. The small sample size limited the statistical analysis power. Conclusions: We present the preliminary data of a single-center retrospective study aimed at understanding the cSVD role on NCs and non-NCs after a liver transplantation in elderly patients. This would encourage a more appropriate multicenter prospective study that will definitely confirm if a neurological screening in old age liver transplant candidates is appropriate

    Role of S128R polymorphism of E-selectin in colon metastasis formation

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    The extravasation of cancer cells is a key step of the metastatic cascade. Polymorphisms in genes encoding adhesion molecules can facilitate metastasis by increasing the strength of interaction between tumor and endothelial cells as well as impacting other properties of cancer cells. We investigated the Ser128Arg (a561c at the nucleotide level) polymorphism in the E-selectin gene in patients with metastatic colon cancer and its functional significance. Genotyping for a561c polymorphism was performed on 172 cancer patients and on an age-matched control population. The colon cancer group was divided into groups with (M(+)) and without observable metastasis (M(-)). For in vitro functional assays, Huvec transfected cells expressing wild-type (WT) or the S128R variant of E-selectin were established to study in vitro binding ability and signal transduction processes of T84 colon cancer cell line. Our results demonstrated that the Arginine(128) allele was more prevalent in the M(+) group than in the M(-) group or normal controls (p < 0.005; odds ratio, 1.56; 95% confidence interval (CI) 1.16-1.92; p < 0.001, odds ratio = 1.65; CI = 1.24-1.99, respectively). In vitro, S128R E-selectin transfected Huvec cells, supported increased adhesion as well as increased cellular signaling of T84 cancer cells compared to WT E-selectin and mock-transfected Huvec cells. These findings suggest that the E-selectin S128R polymorphism can functionally affect tumor-endothelial interactions as well as motility and signaling properties of neoplastic cells that may modulate the metastatic phenotype

    Experiences that \u201creach the heart\u201d. Taking part in a whole body dissection course at the University of Malta

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    This article summarizes the activities of the four-week whole body dissection course the main authors participated in in August 2016 at the dissection hall of the University of Malta (UoM). Our team comprised 10 second-year medicine students from University of Palermo chosen among who had passed the Human Anatomy exam brilliantly. The need to move to the UoM to take part in such activity derives from the lack of practice approach in Italian schools of medicine, focused mostly on the theoretical studies, neglecting practical experience. The heart dissection reveal itself as a huge opportunity to finally apply our anatomical knowledge, improving it and enabling us to compare images took from books to the actual organ. We had the chance to handle a real heart, to appreciate its weight and consistence. We took part in coronary artery courses focusing on their functions within the heart machinery.This article summarizes the activities of the four-week whole body dissection course the main authors partecipated in August 2016 at the dissection hall of the University of Malta (UoM). Our team comprised 10 second-year medicine students from University of Palermo chosen among who had passed the Human Anatomy exam brilliantly. The need to molve to the UoM to take part in such activity derives from the lack of practice approach in Italian schools of medicine, focused mostly on the theoretical studies, neglecting practical experience. The heart dissection reveal itself as a huge opportunity to finally apply our anatomical knowledge, improving it and enabling us to compare image took from books to the actual organ. We had the chance to handle a real heart, to appreciate its weight and consistence. We took part in coronary artery courses focusing on their functions within the heart machinery

    Decision Process in Human-Agent Interaction: Extending Jason Reasoning Cycle

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    The main characteristic of an agent is acting on behalf of humans. Then, agents are employed as modeling paradigms for complex systems and their implementation. Today we are witnessing a growing increase in systems complexity, mainly when the presence of human beings and their interactions with the system introduces a dynamic variable not easily manageable during design phases. Design and implementation of this type of systems highlight the problem of making the system able to decide in autonomy. In this work we propose an implementation, based on Jason, of a cognitive architecture whose modules allow structuring the decision-making process by the internal states of the agents, thus combining aspects of self-modeling and theory of the min

    Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV

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    The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8  TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ÏˆÎł, with the photons being measured through conversions to eâșe⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → ÎŒâșΌ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum

    Test beam performance of a CBC3-based mini-module for the Phase-2 CMS Outer Tracker before and after neutron irradiation

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    The Large Hadron Collider (LHC) at CERN will undergo major upgrades to increase the instantaneous luminosity up to 5–7.5×1034^{34} cm−2^{-2}s−1^{-1}. This High Luminosity upgrade of the LHC (HL-LHC) will deliver a total of 3000–4000 fb-1 of proton-proton collisions at a center-of-mass energy of 13–14 TeV. To cope with these challenging environmental conditions, the strip tracker of the CMS experiment will be upgraded using modules with two closely-spaced silicon sensors to provide information to include tracking in the Level-1 trigger selection. This paper describes the performance, in a test beam experiment, of the first prototype module based on the final version of the CMS Binary Chip front-end ASIC before and after the module was irradiated with neutrons. Results demonstrate that the prototype module satisfies the requirements, providing efficient tracking information, after being irradiated with a total fluence comparable to the one expected through the lifetime of the experiment

    Selection of the silicon sensor thickness for the Phase-2 upgrade of the CMS Outer Tracker

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    During the operation of the CMS experiment at the High-Luminosity LHC the silicon sensors of the Phase-2 Outer Tracker will be exposed to radiation levels that could potentially deteriorate their performance. Previous studies had determined that planar float zone silicon with n-doped strips on a p-doped substrate was preferred over p-doped strips on an n-doped substrate. The last step in evaluating the optimal design for the mass production of about 200 m2^{2} of silicon sensors was to compare sensors of baseline thickness (about 300 ÎŒm) to thinned sensors (about 240 ÎŒm), which promised several benefits at high radiation levels because of the higher electric fields at the same bias voltage. This study provides a direct comparison of these two thicknesses in terms of sensor characteristics as well as charge collection and hit efficiency for fluences up to 1.5 × 1015^{15} neq_{eq}/cm2^{2}. The measurement results demonstrate that sensors with about 300 ÎŒm thickness will ensure excellent tracking performance even at the highest considered fluence levels expected for the Phase-2 Outer Tracker

    Beam test performance of a prototype module with Short Strip ASICs for the CMS HL-LHC tracker upgrade

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    The Short Strip ASIC (SSA) is one of the four front-end chips designed for the upgrade of the CMS Outer Tracker for the High Luminosity LHC. Together with the Macro-Pixel ASIC (MPA) it will instrument modules containing a strip and a macro-pixel sensor stacked on top of each other. The SSA provides both full readout of the strip hit information when triggered, and, together with the MPA, correlated clusters called stubs from the two sensors for use by the CMS Level-1 (L1) trigger system. Results from the first prototype module consisting of a sensor and two SSA chips are presented. The prototype module has been characterized at the Fermilab Test Beam Facility using a 120 GeV proton beam

    Comparative evaluation of analogue front-end designs for the CMS Inner Tracker at the High Luminosity LHC

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    The CMS Inner Tracker, made of silicon pixel modules, will be entirely replaced prior to the start of the High Luminosity LHC period. One of the crucial components of the new Inner Tracker system is the readout chip, being developed by the RD53 Collaboration, and in particular its analogue front-end, which receives the signal from the sensor and digitizes it. Three different analogue front-ends (Synchronous, Linear, and Differential) were designed and implemented in the RD53A demonstrator chip. A dedicated evaluation program was carried out to select the most suitable design to build a radiation tolerant pixel detector able to sustain high particle rates with high efficiency and a small fraction of spurious pixel hits. The test results showed that all three analogue front-ends presented strong points, but also limitations. The Differential front-end demonstrated very low noise, but the threshold tuning became problematic after irradiation. Moreover, a saturation in the preamplifier feedback loop affected the return of the signal to baseline and thus increased the dead time. The Synchronous front-end showed very good timing performance, but also higher noise. For the Linear front-end all of the parameters were within specification, although this design had the largest time walk. This limitation was addressed and mitigated in an improved design. The analysis of the advantages and disadvantages of the three front-ends in the context of the CMS Inner Tracker operation requirements led to the selection of the improved design Linear front-end for integration in the final CMS readout chip
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