861 research outputs found

    Characterisation of autophagy disruption in the ileum of pigs infected with Lawsonia intracellularis

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    Lawsonia intracellularis is the aetiological agent of proliferative enteropathy, an enteric disease endemic in swine. Survival in its intracellular niche of the ileum epithelial lining requires the capacity to subvert, repress or exploit the host immune response to create an environment conducive to bacterial propagation. To better understand how L. intracellularis survives in its intracellular niche, we have performed an investigation into the dynamic relationship between infection and the host autophagy response by immunohistochemistry in experimentally infected porcine ileum samples. Beclin1, a protein required early in the autophagy pathway was observed to be distributed with a basal to apical concentration gradient in the crypts of healthy piglets, whilst infected piglets were observed to have no gradient of distribution and an increase in the presence of Beclin1 in crypts with histological characteristics of L. intracellularis residence. Detecting microtubule-associated protein light chain 3 (LC3) is used as a method for monitoring autophagy progression as it associates with mature autophagosomes. For LC3 there was no notable change in signal intensity between crypts with characteristic L. intracellularis infection and healthy crypts of uninfected pigs. Finally, as p62 is degraded with the internal substrate of an autophagosome it was used to measure autophagic flux. There was no observed reduction or redistribution of p62. These preliminary results of the autophagy response in the ileum suggest that L. intracellularis affects autophagy. This disruption to host ileum homeostasis may provide a mechanism that assists in bacterial propagation and contributes to pathogenesis

    Tri-thermal device sizing for thermophoresis deposition measurements of nanoparticle soot aggregates

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    Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.Thermophoresis is the motion of particles from the hot to the cold region of a gas subjected to a thermal gradient. This phenomenon contributes to the fouling of EGR (Exhaust Gas Recycling) systems in automotive applications. The aim of this work is to develop a tri thermal device to study the collect of soot particles by thermophoresis. In this device soot particles flow in the annular space between two concentric tubes with imposed temperatures. We will use the so called penetration method which is based on the measurement of particle deposition in the test section. The precision of this method is often limited by the low deposition rates; the main objective of this study is then to size an efficient and compact device for thermophoretic deposition, while respecting mechanical and thermal constraints. We used CFD (Computational Fluid Dynamic) numerical simulations and model results to choose an optimal design of the device, which is composed of hot and cold tubes with diameter respectively equal to 87 and 85mm and with 0.5 meter long tubes.cf201

    Domain Adapted Deep-Learning for Improved Ultrasonic Crack Characterization Using Limited Experimental Data

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    Deep learning is an effective method for ultrasonic crack characterization due to its high level of automation and accuracy. Simulating the training set has been shown to be an effective method of circumventing the lack of experimental data common to nondestructive evaluation (NDE) applications. However, a simulation can neither be completely accurate nor capture all variability present in the real inspection. This means that the experimental and simulated data will be from different (but related) distributions, leading to inaccuracy when a deep learning algorithm trained on simulated data is applied to experimental measurements. This article aims to tackle this problem through the use of domain adaptation (DA). A convolutional neural network (CNN) is used to predict the depth of surface-breaking defects, with in-line pipe inspection as the targeted application. Three DA methods across varying sizes of experimental training data are compared to two non-DA methods as a baseline. The performance of the methods tested is evaluated by sizing 15 experimental notches of length (1–5 mm) and inclined at angles of up to 20° from the vertical. Experimental training sets are formed with between 1 and 15 notches. Of the DA methods investigated, an adversarial approach is found to be the most effective way to use the limited experimental training data. With this method, and only three notches, the resulting network gives a root-mean-square error (RMSE) in sizing of 0.5 ± 0.037 mm, whereas with only experimental data the RMSE is 1.5 ± 0.13 mm and with only simulated data it is 0.64 ± 0.044 mm

    IN OPERATED FALLOT IS RV TELEDIASTOLIC VOLUME > 170 ML/M2 A VALID CUT-OFF FOR INDICATION TO PULMONARY VALVE REPLACEMENT?

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    Patients with tetralogy of Fallot (TOF) repaired by means a transannular patch, suffer of residual pulmonary regurgitation leading to right ventricle (RV) dilatation. Several groups have recently demonstrated that if these pts are re-operated for pulmonary valve implant (PVR) since RV tele-diastolic volume (RVtd Vol) exceeds 170 mL/m2, the RV volumes do not decrease to normal values. However the beneficial hemodynamic effects of PVR still have to be weighted against the need for re-operation for valve failure.-

    USP18 restricts PRRSV growth through alteration of nuclear translocation of NF-κB p65 and p50 in MARC-145 cells

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    AbstractAlthough the functions of porcine respiratory and reproductive syndrome virus (PRRSV) proteins are increasingly understood, the roles of host factors in modifying infection are less well understood. Growing evidence places deubiquitination at the core of a multitude of regulatory processes, ranging from cell growth to innate immune response and health, such as cancer, degenerative and infectious diseases. This report provides further information on the functional role of the porcine ubiquitin-specific peptidase 18 (USP18) during innate immune responses to PRRSV. We have shown that constitutive overexpression of the porcine USP18 in MARC-145 cells restricts PRRSV growth, at least in part via early activation of NF-κB. Viral growth of PRRSV may be perturbed by increasing and decreasing nuclear translocation of p65 and p50, respectively. Our data highlight USP18 as a host restriction factor during innate immune response to PRRSV

    OUTCOME OF PULMONARY VALVE REPLACEMENT IN OPERATED FALLOT. CAMPARISON WITH NON REOPERATED PATIENTS

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    Patients with repaired tetralogy of Fallot (TOF) have been shown to be predisposed to exercise intolerance, arrhythmia, and premature death. Pulmonary valve replacement (PVR) reduces the amount of pulmonary regurgitation and leads to a reduced size of the right ventricular cavity. The risk-to-benefit calculus for this procedure, however, has not been well established.-

    Functional magnetic resonance imaging in the evaluation of the elastic properties of ascending aortic aneurysm

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    Objective: To evaluate the aortic wall elasticity using the maximal rate of systolic distension (MRSD) and maximal rate of diastolic recoil (MRDR) and their correlation with the aortic size index (ASI). Methods: Forty-eight patients with thoracic aortic aneurysm were enrolled in this study. A standard magnetic resonance imaging (MRI) protocol was used to calculate MRSD and MRDR. Both MRSD and MRDR were expressed as percentile of maximal area/10-3 sec. ASI (maximal aortic diameter/body surface area) was calculated. A correlation between MRSD, MRDR, ASI, and the patient’s age was performed using regression plot. Results: A significant correlation between MRSD (t=-4,36; r2=0.29; P≤0.0001), MRDR (t=3.92; r2=0.25; P=0.0003), and ASI (25±4.33 mm/m2; range 15,48-35,14 mm/m2) is observed. As ASI increases, aortic MRSD and MRDR decrease. Such inverse correlation between MRSD, MRDR, and ASI indicates increased stiffness of the ascending aorta. A significant correlation between the patient’s age and the decrease in MRSD and MRDR is observed. Conclusion: MRSD and MRDR are significantly correlated with ASI and the patient’s age. They seem to describe properly the increasing stiffness of aortas. These two new indexes provide a promising, accessible, and reproducible approach to evaluate the
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