132 research outputs found

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    The aim of this study was the assessment of the Regional Myocardial Work (RMW) by measuring the stress-strain relationships in the left myocardium, under basic and ischemic conditions. In 11 swines, 4 Sonometrics crystals were placed in the region perfused by the left anterior descending artery (LAD) circumscribing a tetrahedral myocardial volume (TMV). The 1st crystal was situated 45mm below the pulmonary artery, beside the LAD. Under control of the acquisition device, the 2nd was placed 10mm below the 1st following the LAD, the 3rd 10mm at the left side of the 1st and the 4th in equidistant point between the 1st and the 2nd, 5mm deep within the myocardium. A Millar, omnidirectional pressure catheter was placed within the TMV. The 6 distances and intramyocardial pressure measured were digitized and mathematically synthesized. The variation in TMV strain (µv) and stress (µp) was calculated throughout the cardiac cycle, resulting in 2 equations. The relationships between µp and µv result in a stress-strain loop, from which RMW was calculated. Simultaneously, Pulsed Doppler Tissue Imaging (DTI) assessed systolic (VS), early-diastolic (VE) and latediastolic (VA) myocardial velocities. Measurements were performed under basic (B), during ischemia by occlusion LDA for 40 seconds, after 1 and 15 minutes of reperfusion (Occlusion (O), Reperfusion1 (R1) and 2 (R2) periods). The average of RMW, under basic conditions, wa

    PROPRIETES MECANIQUES ET ANTICORROSIVES DES REVETEMENTS ELECTRODEPOSES A BASE DE NICKEL RENFORCES PAR DES NANOPARTICULES DE TIO

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    Le besoin d'améliorer les revêtements pour de meilleures propriétés, a permis le développement des dépôts électrolytiques composites, par l’incorporation de particules solides dans la structure du nickel, tels que l’oxyde de titane connu par sa dureté remarquable et sa stabilité chimique. L’objet de notre travail est l’élaboration et la caractérisation des dépôts composites nickel- oxyde de titane, sur un substrat en acier doux E34. Ces dépôts sont obtenus à partir de bains de watts d’électrodéposition sulfatés. La caractérisation est faite par des méthodes conventionnelles telles que la diffraction des RX et la microscopie électronique à balayage MEB pour les caractérisations morphologiques et structurales. Les mesures mécaniques et les tests de corrosion dans une solution de 3,5 % NaCl viennent pour confirmer la faisabilité des couches déposées. Les techniques utilisées sont celles de masse la perdue et de la polarisation. Les résultats obtenus ont révélé une résistance à la corrosion élevée des dépôts composites. The need for improved the coatings with better properties has developed the requirement for the use of composite electrodeposits, by embedding solid particles in the structure of nickel, such as titanium oxide (TiO2) which is a hard compound, chemically stable and irreducible. The objective of this work is the characterization of the composite deposits nickel titanium on mild steel substrate E 34. These deposits are obtained from watts bath of electrodeposition chlorinated. The characterization has been carried out by XR diffraction and scanning electronic microscopy SEM for the structural and morphological characterization. Mechanical measurements and corrosion tests in a 3,5 % NaCl solution are used to confirm the riability of the deposited films. The techniques used are the weight loss and polarization. The results have revealed a higher corrosion resistance of the composite deposit

    Performance of prototype BTeV silicon pixel detectors in a high energy pion beam

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    The silicon pixel vertex detector is a key element of the BTeV spectrometer. Sensors bump-bonded to prototype front-end devices were tested in a high energy pion beam at Fermilab. The spatial resolution and occupancies as a function of the pion incident angle were measured for various sensor-readout combinations. The data are compared with predictions from our Monte Carlo simulation and very good agreement is found.Comment: 24 pages, 20 figure

    Beam Test of BTeV Pixel Detectors

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    The silicon pixel vertex detector is one of the key elements of the BTeV spectrometer. Detector prototypes were tested in a beam at Fermilab. We report here on the measured spatial resolution as a function of the incident angles for different sensor-readout electronics combinations. We compare the results with predictions from our Monte Carlo simulation.Comment: 7 pages, 5 figures, Invited talk given by J.C. Wang at "Vertex 2000, 9th International Workshop on Vertex Detectors", Michigan, Sept 10-15, 2000. To be published in NIM

    Beam Test Results of the BTeV Silicon Pixel Detector

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    The results of the BTeV silicon pixel detector beam test carried out at Fermilab in 1999-2000 are reported. The pixel detector spatial resolution has been studied as a function of track inclination, sensor bias, and readout threshold.Comment: 8 pages of text, 8 figures, Proceedings paper of Pixel 2000: International Workshop on Semiconductor Pixel Detectors for Particles and X-Rays, Genova, June 5-8, 200

    3D electronics for hybrid pixel detectors – TWEPP-09

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    Future hybrid pixel detectors are asking for smaller pixels in order to improve spatial resolution and to deal with an increasing counting rate. Facing these requirements is foreseen to be done by microelectronics technology shrinking. However, this straightforward approach presents some disadvantages in term of performances and cost. New 3D technologies offer an alternative way with the advantage of technology mixing. For the upgrade of ATLAS pixel detector, a 3D conception of the read-out chip appeared as an interesting solution. Splitting the pixel functionalities into two separate levels will reduce pixel size and open the opportunity to take benefit of technology's mixing. Based on a previous prototype of the read-out chip FE-I4 (IBM 130nm), this paper presents the design of a hybrid pixel read-out chip using threedimensional Tezzaron-Chartered technology. In order to disentangle effects due to Chartered 130nm technology from effects involved by 3D architecture, a first translation of FEI4 prototype had been designed at the beginning of this year in Chartered 2D technology, and first test results will be presented in the last part of this paper

    A primer set for the rapid isolation of scFv fragments against cell surface antigens from immunised rats

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    Antibody phage display is a powerful platform for discovery of clinically applicable high affinity monoclonal antibodies against a broad range of targets. Libraries generated from immunized animals offer the advantage of in vivo affinity-maturation of V regions prior to library generation. Despite advantages, few studies have described isolation of antibodies from rats using immune phage display. In our study, we describe a novel primer set, covering the full rat heavy chain variable and kappa light chain variable regions repertoire for the generation of an unbiased immune libraries. Since the immune repertoire of rats is poorly understood, we first performed a deep sequencing analysis of the V(D)J regions of VH and VLK genes, demonstrating the high abundance of IGVH2 and IGVH5 families for VH and IGVLK12 and IGVLK22 for VLK. The comparison of gene’s family usage in naïve rats have been used to validate the frequency’s distribution of the primer set, confirming the absence of PCR-based biases. The primers were used to generate and assemble a phage display library from human CD160-vaccinated rats. CD160 represents a valid therapeutic target as it has been shown to be expressed on chronic lymphocytic leukaemia cells and on the surface of newly formed vessels. We utilised a novel phage display panning strategy to isolate a high affinity pool (KD range: 0.399–233 nM) of CD160 targeting monoclonal antibodies. Subsequently, identified binders were tested for function as third generation Chimeric Antigen Receptors (CAR) T cells demonstrating specific cytolytic activity. Our novel primer set coupled with a streamlined strategy for phage display panning enable the rapid isolation and identification of high affinity antibodies from immunised rats. The therapeutic utility of these antibodies was demonstrated in CAR format

    Small poly-L-lysines improve cationic lipid-mediated gene transfer in vascular cells in vitro and in vivo

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    The potential of two small poly-L-lysines ( sPLLs), low molecular weight sPLL ( LMW-L) containing 7 - 30 lysine residues and L18 with 18 lysine repeats, to enhance the efficiency of liposome-mediated gene transfer ( GT) with cationic lipid DOCSPER {[}1,3- dioleoyloxy- 2-( N-5-carbamoyl-spermine)-propane] in vascular smooth muscle cells ( SMCs) was investigated. Dynamic light scattering was used for determination of particle size. Confocal microscopy was applied for colocalization studies of sPLLs and plasmid DNA inside cells. GT was performed in proliferating and quiescent primary porcine SMCs in vitro and in vivo in porcine femoral arteries. At low ionic strength, sPLLs formed small complexes with DNA ( 50 100 nm). At high ionic strength, large complexes ( 11 mu m) were observed without any significant differences in particle size between lipoplexes ( DOCSPER/ DNA) and lipopolyplexes ( DOCSPER/ sPLL/ DNA). Both sPLLs were colocalized with DNA inside cells 24 h after transfection, protecting DNA against degradation. DOCSPER/ sPLL/ DNA formulations enhanced GT in vitro up to 5- fold, in a porcine model using local periadventitial application up to 1.5- fold. Both sPLLs significantly increased liposome- mediated GT. Poly-L-lysine L18 was superior to LMW-L since it enabled maximal GT at a 10-fold lower concentration. Thus, sPLLs may serve as enhancers for GT applications in SMCs in vitro and in vivo using local delivery. Copyright (c) 2007 S. Karger AG, Basel
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