Search results for "RILL"

CATHAR : CATHeter for ARRhythmias : determination of depth of burned biological tissues with microwave

2015

Cardiac arrhythmia substrates may be treated by intracardiac ablations which consist in burning specific atrial or ventricular endocardial substrates. Created lesions which are not transmural may be responsible for arrhythmia recurrences. To date, the depth of the lesion inside the endocardium can't be assessed accurately during the procedures. Our experimental work has focused on microwave characterization of biological tissues (in vitro) to assess the burn depth. Using a reflection technique with a coaxial probe in contact with tissues, measurements were made over a wide frequency range (100 MHz to 6 GHz). The measured reflection coefficient is known to be directly related to the dielectr…

One-step polymerase chain reaction-based typing of Helicobacter pylori vacA gene: association with gastric histopathology.

2000

Heterogeneity of the Helicobacter pylori vacA gene may be associated with bacterial virulence and presentation. In this study, the possible correlation between vacA genotypes and gastric histopathology was investigated. Using a modified one-step polymerase chain reaction (PCR)-based method, 122 of 131 H. pylori isolates obtained from 63 of 67 patients from Germany were classified into distinct vacA genotypes according to their signal sequence (s1 or s2) and their midregion alleles (m1 or m2). A possible subtype of m1, now alluded to as m3, was identified in one-third of the isolates. Signal sequence s1 was significantly associated with higher H. pylori density but not with gastric inflammat…

In Situ Characterization of Hfq Bacterial Amyloid: A Fourier-Transform Infrared Spectroscopy Study

2019

Hfq is a bacterial protein that regulates gene expression at the post-transcriptional level in Gram-negative bacteria. We have previously shown that Escherichia coli Hfq protein, and more precisely its C-terminal region (CTR), self-assembles into an amyloid-like structure in vitro. In the present work, we present evidence that Hfq unambiguously forms amyloid structures also in vivo. Taking into account the role of this protein in bacterial adaptation and virulence, our work opens possibilities to target Hfq amyloid self-assembly and cell location, with potential to block bacterial adaptation and treat infections. Fil: Partouche, David. Centre National de la Recherche Scientifique; Francia. …

Hybrid DFT calculations of the atomic and electronic structure for ABO3 perovskite (001) surfaces

2005

Abstract We present the results of first-principles calculations on two possible terminations of the (0 0 1) surfaces of SrTiO3, BaTiO3, and PbTiO3 perovskite crystals. Atomic structure and the electronic configurations were calculated for different 2D slabs, both stoichiometric and non-stoichiometric, using hybrid (B3PW) exchange-correlation technique and re-optimized basis sets of atomic (Gaussian) orbitals. Results are compared with previous calculations and available experimental data. The electronic density distribution near the surface and covalency effects are discussed in details for all three perovskites. Both SrTiO3 and BaTiO3 (0 0 1) surfaces demonstrate reduction of the optical …

Intraosseous monitoring of drilling in lumbar vertebrae by ultrasound: An experimental feasibility study.

2016

The rationale for this project is to evaluate the efficiency of a novel sonographic method for measurements of interosseous distances. The method utilizes a propagating ultrasonic beam through aqueous milieu which is directed as a jet into a drilled tract. We used a plastic model of human L5 vertebra and ex vivo specimen of L5 porcine vertebra and generated 2 mm in diameter tracts in vertebral pedicles. The tracts were created in the "desired" central direction and in the "wrong" medial and lateral directions. The drilled tracts and the residual, up to opposite cortex, distances were measured sonographically and mechanically and compared statistically. We show that "true" mechanical measure…

Detailed Anatomical and Electrophysiological Models of Human Atria and Torso for the Simulation of Atrial Activation

2015

Atrial arrhythmias, and specifically atrial fibrillation (AF), induce rapid and irregular activation patterns that appear on the torso surface as abnormal P-waves in electrocardiograms and body surface potential maps (BSPM). In recent years both P-waves and the BSPM have been used to identify the mechanisms underlying AF, such as localizing ectopic foci or high-frequency rotors. However, the relationship between the activation of the different areas of the atria and the characteristics of the BSPM and P-wave signals are still far from being completely understood. In this work we developed a multi-scale framework, which combines a highly-detailed 3D atrial model and a torso model to study th…

P4020Use of novel oral anticoagulants in patients with atrial fibrillation and moderate to severe renal dysfunction: findings from a prospective nati…

2017

Isolation of the left atrial surface from cardiac multi-detector CT images based on marker controlled watershed segmentation

2006

The delineation of left atrium (LA) and pulmonary veins (PVs) anatomy from high resolution images holds importance for atrial fibrillation (AF) investigation and treatment. In this study, a semiautomatic segmentation procedure for LA and PVs inner surface from contrast enhanced CT data was developed. The procedure consists of a three dimensional marker controlled watershed segmentation applied to the external morphological gradient, followed by variable threshold surface extraction from the original intensity image. A preliminary anisotropic non-linear filtering was implemented to improve the S/N ratio of CT images. The performance of segmentation was evaluated on cardiac CT scans of 12 AF …

Effect of Elongational Flow and Polarity of Organomodified Clay on Morphology and Mechanical Properties of a PLA Based Nanobiocomposite

2016

Abstract In biodegradable polymer world nanobiocomposites represent a new group of materials filled with inert nanoparticles that shows very interesting properties and the biodegradability of the matrix. In this work we have studied the effect of the polarity of the organomodified montmorillonite and of the elongational flow on the morphology and the rheological and mechanical properties of a new nanobiocomposite with a matrix of biodegradable PLA based blend. The elastic modulus enhances in presence of the nanofiller and this increase is larger and larger with the increment of the orientation. The tensile strength does not show any significant change at the same level of orientation. Moreo…

Glial Promoter Selectivity following AAV-Delivery to the Immature Brain

2013

Recombinant adeno-associated virus (AAV) vectors are versatile tools for gene transfer to the central nervous system (CNS) and proof-of-concept studies in adult rodents have shown that the use of cell type-specific promoters is sufficient to target AAV-mediated transgene expression to glia. However, neurological disorders caused by glial pathology usually have an early onset. Therefore, modelling and treatment of these conditions require expanding the concept of targeted glial transgene expression by promoter selectivity for gene delivery to the immature CNS. Here, we have investigated the AAV-mediated green fluorescent protein (GFP) expression driven by the myelin basic protein (MBP) or gl…