Search results for "mecA"
showing 10 items of 475 documents
Meticilīnrezistento Staphylococcus intermedius grupas baktēriju identifikācija un izplatība suņiem Latvijā
2015
Meticilīnrezistentā Staphylococcus intermedius grupa (MRSI) ir galvenā rezistento patogēnu grupa mazajiem dzīvniekiem veterinārajā medicīnā. No gandrīz visām veterinārajām klīnikām pasaulē tiek ziņots par arvien vairāk pieaugošo rezistenci, īpašus draudus rada multirezistence. Meticilīna rezistenci nosaka mecA gēns, kas ir insertēts hromosomālā kasetē, pazīstamā kā stafilokoku hromosomālā kasete (staphylococcal chromosomal cassette – SCCmec). Darba mērķis ir identificēt meticilīnrezistentās S. intermedius grupas baktērijas Latvijā un noteikt to izplatību, kā arī optimizēt noteikšanas procedūru. Izmantojot skrīninga metodes, Brilliance MRSA2 agaru un Mannitol Salt agaru ar 2 mg/L cefoksitīnu…
mecA gēna noteikšana klīniskajos Staphylococcus aureus celmos
2017
Staphylococcus aureus ir viens no galvenajiem nozokomiālo infekciju izraisītājiem daudzās attīstītās pasaules valstīs. S.aureus samērā bieži ir meticilīnrezistents, tas nozīmē, ka tam ir rezistence pret visiem klasiskajiem beta laktāmu antibakteriālajiem līdzekļiem. Meticilīnrezistenci nosaka mecA gēns un tā integrācija baktērijas genomā. Baktēriju rezistences pieauguma dēļ būtiski ir noteikt atbilstošu antibakteriālo līdzekļu terapiju efektīvai ārstēšanai. Darba mērķis ir mecA gēna noteikšana klīniskajos Staphylococcus aureus celmos, kas iegūti no pacientiem, kuri ir ilgstoši uzturējušies veselības aprūpes iestādēs. Darbā tika izmantots GenoType® Staphylococcus tests, lai varētu noteikt me…
Détection des ruptures de fibres et du délaminage dans les composites verre/époxy et carbone/époxy à l'aide de structures propagatives dans la gamme …
2009
National audience; On présente dans cet article la détection de ruptures de fibre et du délaminage dans les composites unidirectionnels verre/époxy et carbone/époxy en utilisant des structures propagatives électromagnétiques dans la gamme des micro-ondes.
Modelling the effect of porosity on the mechanical properties of unidirectional composites. The case of thick-walled pressure vessels
2018
International audience; The present article highlights morphological features present in composite pressure vessels. The use of X-ray microtomography provides three-dimensional information about the voids in a large thick-walled type 3 pressure vessel at the mesoscopic scale. The observations show that the porosity structure depends strongly on composite thickness and orientation. A numerical approach is proposed to model realistically the damage phenomena in pressure vessels.
Transport de la variabilité dans les matériaux composites = Uncertainties propagation in composite materials
2009
National audience; Dans ce travail, une méthodologie de transport d'incertitudes à travers les différentes échelles d'observation des matériaux composites : (i) micro (fibres et matrice), (ii) méso (pli), (iii) macro (matériau stratifié) est proposée. L'objectif est d'intégrer à l'échelle macro (celle du calcul de structure) l'effet des incertitudes venant de l'échelle micro et celle des incertitudes introduites à chacune des échelles méso et macro. La démarche proposée s'appuie sur l'élaboration dès l'échelle micro de distributions statistiques bâties sur l'analyse morphologique et obtenues grâce à la génération de matériaux virtuels.
Durability of a 3D woven composite assisted by finite element multi-scale modelling
2012
International audience; The textile composite studied is a 3D woven composite. A unit cell is defined by using microscopic examinations of the microstructure. A multiscale approach assisted by the finite element method is performed in order to estimate the effective properties of the composite and then to access to local stress field. This approach allows the determination of the kind of load to which warp yarns are subjected. Moreover, detailed analysis of damaged model using different configurations of broken yarns are treated. The evolution of the stress concentration coefficient highlight the load transfers due to consecutive yarn breaks.
The numerical challenges in multiphysical modeling of laser welding with arbitrary Lagrangian-Eulerian method
2018
International audience; The interaction of high power laser beam with metallic materials produces a number of interconnected phenomena that represent a serious challenge for numerical modeling, especially for creation of auto-consistent models. Additional difficulty consists in lack of data on materials properties at the temperatures superior to their melting point. The present work summarizes the numerical challenges in creation and validation of free-surface models using ALE moving mesh coupled with heat transfer equation and Navier-Stokes fluid flow.
Predicting mechanical behaviour and damage kinetics of a 3D interlock composite materials by using a multiscale approach
2012
International audience; The present work aims to investigate the mechanical behaviour and the damage kinetics of a3D interlock woven fabric composite, especially used for natural gas tanks dedicated to thetransportation industry. On the one hand, we aim at predicting the macroscopic coefficients ofthe stiffness matrix by homogenization multiscale approach. For this, we identified a basicunit cell which represents well the composite microstructure. On the other hand, damagemechanisms are analyzed: optical microscopy examinations on damaged specimens revealedseveral types of defects. We used the same multi-scale approach to assess the impact of thesedefects on the decrease of stiffness.
Patient-specific computational evaluation of stiffness distribution in ascending thoracic aortic aneurysm
2021
Quantifying local aortic stiffness properties in vivo is acknowledged as essential to assess the severity of an ascending thoracic aortic aneurysm (ATAA). Recently, the LESI (local extensional stiffness identification) methodology has been established to quantify non-invasively local stiffness properties of ATAAs using electrocardiographic-gated computed tomography (ECG-gated CT) scans. The aim of the current study was to determine the most sensitive markers of local ATAA stiffness estimation with the hypothesis that direct measures of local ATAA stiffness could better detect the high-risk patients. A cohort of 30 patients (12 BAV and 18 TAV) referred for aortic size evaluation by ECG-gated…
HHT-alpha and predictor-corrector scheme for dynamic contact problem by Nitsche's method
2022
Dans ce travail nous sommes intéressés par le problème de contact unilatéral en dynamique et sans frottement. Nous nous concentrons sur l'évolution en temps de l'impact d'un corps élastique linéaire sur un obstacle rigide, et avons souhaité en particulier étudier comment combiner des schémas en temps comme HHT et prédicteur-correcteur avec un traitement du contact via Nitsche, ce qui n'a jamais été effectué auparavant. Nous présenterons aussi quelques résultats numériques en faisant attention au comportement numérique : stabilité du schéma, conservation ou non de l'énergie et oscillations parasites. Mots clés-problème de contact, méthode de Nitsche, éléments finis, dynamique.