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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

Estudo do volume pulmonar fetal na predição dos resultados perinatais de fetos com derrame pleural \"isolado / Three-dimensional ultrasonographic assessment of fetal lung volume as a prognostic factor in isolated pleural effusion

Rogério Caixeta Moraes de Freitas 14 December 2011 (has links)
OBJETIVO: O objetivo deste estudo foi predizer o prognóstico perinatal em fetos com derrame pleural isolado por meio da medida do volume pulmonar estimado pela ultrassonografia tridimensional. MÉTODO: Estudo retrospectivo, entre julho de 2005 e julho de 2010, com 19 fetos com derrame pleural isolado (ausência de causas infecciosas, imunes, anomalias cromossômicas ou estruturais associadas) acompanhados no Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo. Os volumes pulmonares foram obtidos pela ultrassonografia tridimensional (Voluson 730 Expert, GE Medical System, Kretzechnick, Áustria) em dois períodos, no momento do diagnóstico (20 26 semanas) e próximo ao parto (duas semanas antecedentes ao parto ou até 36 semanas), e mensurados pela técnica VOCAL (Virtual Organ Computer Aided Analysis) com rotação de 30º. Os volumes obtidos (observados) foram comparados com valores esperados para idade gestacional, e a razão entre o volume total fetal observado/esperado (VPTo/e) foi avaliada de acordo com a mortalidade perinatal e morbidade neonatal (necessidade de ventilação mecânica por mais que 48 horas). RESULTADOS: Dezenove fetos com derrame pleural isolado foram analisados no período do estudo. Doze (63,2%) crianças sobreviveram. Dos sobreviventes, sete (58,3%) apresentaram morbidade respiratória. O VPTo/e no primeiro exame ultrassonográfico não se associou significativamente com mortalidade (VPTo/e: 0,42±0,19 nos sobreviventes contra 0,30±0,08 nos não sobreviventes, p=0,11). No segundo exame, por outro lado, VPTo/e foi significativamente menor nos casos que faleceram (0,24±0,08) em relação aos sobrevivente (0,58±0,21; p<0,01) e nos que necessitaram de ventilação mecânica prolongada (0,35±0,08) comparados aos que não necessitaram (0,68±0,10; p<0.01). CONCLUSÃO: O volume pulmonar fetal medido pela ultrassonografia tridimensional pode ser utilizado para predizer o prognóstico de fetos com derrame pleural isolado. / OBJECTIVE The aim of the present study was to predict the perinatal outcome in isolated pleural effusion using fetal lung volumes assessed by three-dimensional ultrasonography. METHODS: A retrospective study conducted between July 2005 and July 2010, in which 19 fetuses with isolated pleural effusion (absence of infection, immunological causes, chromosomal anomalies and associated structural anomalies) at Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo. Fetal lung volumes were assessed by three-dimensional ultrasonography (Voluson 730 Expert, GE Medical System, Kretzechnick, Áustria) in two periods: at diagnosis (20-26 weeks) and nears the delivery (2 weeks before delivery or at 36 weeks), by VOCAL technique (Virtual Organ Computer Aided Analysis) with rotation of 30o. The observed volumes were compared to expected values for determine gestational age, and the observed/expected total fetal lung volume ratio (o/e-TFLV) was evaluated according to perinatal death and neonatal morbidity (need for mechanical ventilation longer than 48 hours). RESULTS: A total of 19 fetuses with isolated pleural effusion were evaluated during the study period. Twelve (63.2%) infants survived. Among the survivors, seven (58.3%) had severe respiratory distress at birth. The o/e-TFLV at the first ultrasound examination was not associated statistically with mortality (o/e-TLFV: 0.42±0.19 in survivors x 0.30±0.08 among those that died, p=0.11). On the second ultrasound examination, on the other hand, the o/e-TFLV was significantly reduced in those cases that died (0.24±0.08) whilst in survivors (0.58±0.21; p<0.01) and in those that needed mechanical ventilation (0.35±0.08) when compared to those that did not need it (0.68±0.10; p<0.01). CONCLUSION: Fetal lung volumes measured by three-dimensional ultrasonography may be useful to predict perinatal outcome in fetuses with primary pleural effusion
92

Habilidades auditivas verbais e temporais em crianças de 6 a 10 anos com e sem episódios comprovados de perda auditiva condutiva flutuante recorrente, nos primeiros anos de vida / Verbal and temporal auditory skills in children 6 to 10 years with and without episodes of proven floating recurrent conductive hearing loss, in the first years of life

Priscila Cruvinel Villa 21 January 2014 (has links)
A otite média, afecção comum na infância, acarreta uma perda auditiva condutiva flutuante, pois uma vez tratada os limiares auditivos voltam aos valores normais. Preocupação ocorre quando estes episódios tornam-se recorrentes levando a criança a receber uma estimulação sonora inconsistente do sistema nervoso auditivo central, dificultando a percepção dos sons da fala. O objetivo do presente estudo foi investigar se crianças com episódios recorrentes e comprovados de otite média com efusão apresentam alterações das habilidades auditivas que compõe o processamento auditivo. Foram avaliadas 59 crianças com idade entre 6 e 10 anos, divididas em dois grupos: grupo experimental composto por 29 crianças de ambos os gêneros com histórico documentado de otite media com efusão, perda auditiva condutiva nos primeiros anos de vida e com e sem história de cirurgia para colocação de tubo de ventilação na idade pré-escolar e escolar; e grupo controle, composto por 30 crianças, pareadas em idade e gênero com o grupo experimental, mas sem história da afecção. Na avaliação das habilidades auditivas que compõe o processamento auditivo foram utilizados o teste fala com ruído (TFR), teste dicótico de dígitos (TDD) e teste Gaps-in-noise (GIN). Todas as crianças no momento da avaliação estavam livres de perda auditiva condutiva. Os resultados mostraram que: os dois grupos não apresentavam diferenças dos limiares tonais, no momento da avaliação; o grupo experimental apresentou resultados inferiores no TFR e GIN, tanto na análise quantitativa quanto na qualitativa; o TDD apenas na análise qualitativa diferenciou os dois grupos. Pode-se concluir, no presente estudo, , que crianças com história de otite média com efusão recorrente e persistente, nas fases pré-escolar e escolar, apresentaram transtorno do processamento auditivo. / Otitis media, a common affection in childhood, causes a fluctuating conductive hearing loss, because once treated the hearing thresholds back to normal values. Concern occurs when these episodes become recurring leading the child to receive an inconsistent sound stimulation auditory central nervous system, it difficult for the perception of speech sounds. The aim of this study was to investigate whether children with recurrent episodes of proven otitis media with effusion present alterations of auditory skills that composes the auditory processing. We evaluated 59 children with ages between 6 and 10 years, divided into two groups: the experimental group comprised of 29 children of both genders with documented history of otitis media with effusion, conductive hearing loss in the early years of life and with and without history of surgery for ventilation tube placement in preschool and school age; and the control group, consisting of 30 children, paired in age and gender with the experimental group, but no history of the disease. In the assessment of auditory skills that make up the auditory processing was used Speech in Noise Test (SNT), Dichotic Digits Test (DDT) and Gaps in Noise test (GIN). All children had at the time of assessment were free of conductive hearing loss. The results showed that: the two groups showed no differences in tonal thresholds, at the time of the assessment; the experimental group showed results below the SNT and GIN, both in qualitative and in quantitative analysis; DDT only in qualitative analysis differentiated the two groups. It can be concluded, with the results of the work, that children with a history of otitis media with effusion recurrent and persistent, pre-school and school phases, may have auditory processing disorder.
93

Comportements sous sollicitations tribologiques d'un matériau énergétique : Recherche des conditions de contrôle de la sécurité de fabrication / Behaviors of an energetic material under tribological stresses : Control conditions research of manufacturing security

Charlery, Rudy 02 July 2014 (has links)
Les matériaux énergétiques sont, par définition, des matériaux susceptibles de dégager un volume important de gaz, en se décomposant via les phénomènes suivants : combustion, déflagration ou détonation. Ils sont notamment utilisés dans les secteurs industriels de l’automobile (déploiement d’airbag), du militaire (propulsion de missiles tactiques et stratégiques, munitions) et du spatial (boosters de lanceurs spatiaux type Ariane 5). La maîtrise de leur fabrication nécessite que soient vérifiées certaines contraintes spécifiques rencontrées lors de leur mise en œuvre dans un malaxeur bivis. En effet, ce procédé de malaxage en continu induit de fortes évolutions de gradients de pression et de cisaillement au sein du matériau énergétique (entrefers réduits...) qui peuvent initier les constituants fluides et solides. Par conséquent, dans un souci de parfaite maîtrise des risques industriels, les conditions tribologiques menant à l’initiation d’un matériau énergétique, ici le propergol, lors de sa fabrication, doivent être étudiées. Malheureusement, à cause de la confidentialité industrielle liée à ce secteur d’activité, la bibliographie de la tribologie des propergols est limitée. Il apparait toutefois que peu d’études portent effectivement sur le comportement tribologique du troisième corps, c’est à dire le propergol. Ce dernier étant hétérogène (mélange de constituants fluides et de solides), il est donc nécessaire d’appréhender les écoulements internes qui l’animent sous sollicitations tribologiques. Ainsi, pour reproduire les sollicitations mécaniques élémentaires (compression et cisaillement) appliquées par les deux premiers corps que sont les vis et le fourreau, et subies par le troisième corps lors du malaxage, il a été choisi d’utiliser une approche couplée expérimentale et numérique. Cette dernière s’organise autour de l’instrumentation d’un dispositif de sécurité permettant la sollicitation par frottement du propergol et de la modélisation par éléments discrets du triplet tribologique (parois supérieure et inférieure des premiers corps, et troisième corps). Il est ainsi apparu un comportement tribologique caractéristique du troisième corps : des ségrégations entre les constituants mènent à un arrangement selon trois couches superposées dans l’épaisseur du troisième corps. Ces ségrégations sont issues de la mise en place de débits internes, spécifiques à chaque nature et géométrie de constituants. Ces débits sélectionnent les constituants présents dans l’aire de contact et favorisent l’existence de conditions tribologiques favorables à l’initiation du troisième corps (assèchement de l’épaisseur, localisation des efforts appliqués au troisième corps ...). L’ensemble de ces débits permet de reconstituer un circuit tribologique d’initiation d’un propergol et ainsi d’envisager des solutions techniques permettant d’endiguer la mise en place des conditions défavorables à la fabrication en sécurité d’un propergol dans un malaxeur bivis. / By definition, energetic materials can deliver a huge amount of gas and cause different kinds of phenomena, such as: burning, deflagration or detonation. These materials are mainly used in the automotive industry (airbag deployment), military devices (missiles, ammunition) and space launchers (Ariane 5 boosters and pyrotechnic devices). The manufacturing process, although well controlled by the historical “batch” process, presents several challenges when it is transferred to the continuous mixing process, using a twin-screw mixer device. Indeed, this last device induces extreme evolutions of pressure gradients and shearing gradients (reduced air-gap...). Plus, the energetic material is composed of fluid components and different diameters of solid components that can ignite by shearing. Consequently, tribological conditions leading to the ignition of an energetic material, a solid propellant, are studied during its manufacturing in a twin-screw mixer. Unfortunately, because of the industrial confidentiality on solid propellants, the bibliography on the solid propellants tribology is limited. However it appears that too few studies have effectively dealt with the tribological behaviour of this third body. By nature, this last is a composite material; therefore it is necessary to understand internal flows that evolve from tribological stresses. Thus, a coupled approach experimental and numerical is chosen in order to reproduce the mechanical elementary stresses applied by the two first bodies (top of screw thread and bore of the barrel element), and undergone by the third body during its manufacturing in a twin-screw mixer (compression and shearing). This approach consists of the instrumentation of a security test that shears the solid propellant and a discrete element simulation of the tribological triplet (inferior and superior first bodies, and the third body). The distinctive tribological behaviour of this third body appears obvious: different types of component segregations lead to a three superposed layer arrangement of the solid propellant thickness. These segregations come from the creation of internal component flows, specific to the nature and the geometry of the third body components. These flows select the components that remain within the contact area and also establish the tribological conditions that favour the third body ignition (gradient of mobility between solid components, draining of the third body thickness, localization of the efforts applied to the third body…). Ultimately, this study rebuilds the ignition tribological circuit(s) of a solid propellant and offers technical solutions to prevent the materialisation of unfavourable conditions to a safe solid propellant manufacturing in a twin-screw mixer.
94

Immittance in infants 0–12 months: Measurements using a 1000 Hz probe tone

Van Rooyen, Sonia 29 October 2007 (has links)
Rapid implementation of universal newborn hearing screening programs has exposed a need for a reliable test of middle ear function for timely identification of middle ear pathology and for differentiation between true sensorineural and conductive hearing losses. Use of higher probe tone frequencies for the assessment of immitance measures have proven to be more reliable and accurate in identifying MEE in infants. However a lack of classification-guidelines and age specific normative data exists. This study investigated the characteristics and normative values of high frequency tympanometric and acoustic reflex results for infants (n = 936 ears). Participants were 510 infants (262 male, 248 female) aged 0 – 12 months (mean age = 12.8 weeks) recruited from primary health care and immunization clinics in a South African community. A three-part procedure was performed on each test ear: 1) OAEs were recorded and pass results served as control variable for normal middle ear functioning; 2) 1000 Hz probe tone admittance, susceptance and conductance tympanograms were recorded and analysed in terms of shape, tympanometric peak pressure and maximum (peak) admittance; 3) 1000 Hz probe tone acoustic reflexes, measured with a 1000 Hz ipsilateral stimulus, were recorded and thresholds determined. Significant associations were observed between tympanogram shape, and OAE pass or fail results. 93% of ears with an OAE pass result displayed peaked tympanograms, while 79% of ears with absent OAE’s displayed flat tympanograms. Single peaked tympanograms were recorded in 782 ears (84%), double peaked tympanograms in 41 (4%) ears and flat sloping tympanograms in 112 (12%) ears. Admittance (Ya) tympanograms for the total sample displayed a mean admittance value of 2.9 mmho, with a standard deviation of 1.1 mmho. The 90th percent range was determined at 1.5 mmho (5th percentile) to 4.9 mmho (95th percentile). Mean tympanometric peak pressure in Ya tympanograms was 0.1 daPa, with a standard deviation of 61 daPa. The 90th percent range was -110 daPa to 90 daPa for the 5th and 95th percentiles respectively. Gender specific norms indicated a higher admittance for male ears. Age specific norms indicate a gradual increase in admittance indicating the need for age specific normative classification systems. Ipsilateral 1000 Hz stimuli acoustic reflex measurement proved successful with a 1000 Hz probe tone and present reflexes were recorded in 84% of ears tested. Significant association between acoustic reflex presence, OAE pass and peaked tympanogram results were observed. The normative tympanometric values derived from the cohort may serve as a guide for identification of middle ear effusion in neonates. High frequency tympanometry in combination with acoustic reflexes proves a useful measure for verifying middle ear functioning in young infants. / Dissertation (M (Communication Pathology))--University of Pretoria, 2006. / Speech-Language Pathology and Audiology / M (Communication Pathology) / unrestricted
95

Beiträge zur Untersuchung des Strahlaustrittsverhaltens aus Effusionskühlbohrungen

Schlott, André 08 December 2016 (has links)
Die Kühlung thermisch hoch belasteter Bauteile wird häufig mit Kühlverfahren realisiert, die auf dem Prinzip des Massetransports durch die Bauteilwand beruhen. Neben der Film- und Transpirationskühlung gehört die Effusionskühlung zu diesen Verfahren und basiert auf einer Reihe oder einem Raster von Bohrungen. Dieser Ansatz ermöglicht sowohl den Abtransport von Wärme aus dem Bauteil als auch die Ausbildung eines schützenden Kühlmittelfilms auf der Bauteiloberfläche. Viele Autoren beschäftigten sich in ihren Arbeiten mit den Auswirkungen der Filmkühlung auf den Wärmeübergang an der Bauteilwand und definierten einen Filmkühlwirkungsgrad, der die Effektivität der Kühlung widerspiegelt. Auch die Freistrahlen aus Effusionskühlbohrungen wurden mit diesen Mitteln untersucht und eine Vielzahl unterschiedlicher Einflussgrößen auf den Filmkühlwirkungsgrad identifiziert. Dazu gehören insbesondere geometrische Bedingungen, wie z.B. der Bohrungswinkel, das Verhältnis von Länge zu Durchmesser der Bohrung und die Austrittsgeometrie der Bohrungen. In späteren Beiträgen analysierten verschiedene Autoren die Einflüsse der Turbulenz sowie der Stoffwerte von Kühlmittel und Hauptströmung. Dabei kamen meist Luft und seltener Kohlendioxid oder Stickstoff als Kühlmittel zum Einsatz. In den letzten Jahren wurde das Verhalten des Kühlmittelstrahls vor allem numerisch untersucht. Dabei beschränkte sich das Berechnungsgebiet oftmals auf das direkte Umfeld der Effusionskühlbohrung und die Identifikation und Beschreibung auftretender Wirbelstrukturen. Der Bereich weiter stromab der Bohrung blieb oft unberücksichtigt. Die vorliegende Arbeit verfolgt den Ansatz, den Kühlmittelstrahl in der Hauptströmung zu beobachten. Das wird durch die Verwendung von Helium und Argon als Kühlmittel möglich, denn diese Gase können in der Luftströmung detektiert werden. Durch eine in zwei Richtungen bewegliche Kombisonde wird Gas aus der Grenzschicht abgesaugt und die Konzentration des Kühlmittels bestimmt. Die so an diskreten Punkten stromab der Effusionskühlbohrung erhaltenen Konzentrations- und Geschwindigkeitsprofile ermöglichen die Verfolgung des Kühlmittelstrahls und dessen Wechselwirkungen mit der Hauptströmung. Für eine vergleichende Analyse der gemessenen Profile entstand ein empirisches Verfahren zur Systematisierung der gesamten Messdaten. Die Definition einer mittleren Kühlmittelkonzentration innerhalb einer zweckmäßig festgelegten Höhe über der Wand und eines normierten Einblasparameters, der das Verhältnis der molaren Massen von Kühlmittel und Hauptströmung berücksichtigt, sind der Kern des empirischen Verfahrens. Für Vergleiche mit der Literatur erfolgte die Berechnung eines Filmkühlwirkungsgrads auf Basis der Massebilanz in der Grenzschicht und der mittleren Kühlmittelkonzentration. Während der Datenauswertung zeigte sich, dass der Bohrungswinkel einen geringen Einfluss auf die mittlere Kühlmittelkonzentration hat und so ein Bohrungswinkel von 30° ein guter Kompromiss zwischen Herstellungsaufwand und Kühlwirkung ist. Kühlmedien mit geringer molarer Masse und hoher spezifischer Wärmekapazität sollten bevorzugt werden, da deren Kühlwirkung hoch, der Einfluss auf die Grenzschicht aber gering ist. / The cooling of thermally heavily loaded components is commonly performed by injecting a mass flow through the component’s wall into the hot flow, which is called Film cooling. The main goal is to form a coolant film to reduce the hot side heat transfer and to absorb thermal energy in order to protect the component’s wall. There are different techniques available called film cooling, transpiration cooling and effusion cooling. By applying transpiration cooling, the cooling fluid is injected through a porous material into the hot gas flow. Unfortunately, these porous materials do not have the physical strength required to work within gas turbines. If the injection is done with a row or a pattern of holes so the cooling film is renewed at certain positions, the cooling technique is called effusion cooling. Film cooling means the injection of fluid through a slot without renewing the film. Many authors analyze the effect of the film or effusion cooling on the wall temperature, the heat transfer coefficient or the cooling effectiveness. Many influencing factors were identified, such as the length to diameter relation, the hole’s alignment, fluid properties as well as turbulence and vortices. Recent works use numerical simulations to investigate the turbulent flow and vortex development in the near field of the injection hole. Due to the complexity of the simulation, the effects far downstream area were not covered by these simulations. This work investigates the behavior of the cooling jet within the boundary layer above the wall. Therefore a foreign gas (Helium, Argon) was injected as coolant into a cross flow and a pitot probe was used to get gas samples out of the boundary layer and the coolant gas fraction was measured. The measured concentration was empirically systematized by comparative data analysis. Therefore, a mean concentration within a certain height above the wall was calculated. Also a normed blowing rate was used to include the molar masses of coolant and cross flow. With this mean concentration a cooling effectiveness is calculated based on a balance model and compared to the results in the literature. As a result of the data evaluation, the hole’s angle was found to have a minor influence on the mean coolant concentration. An angle of about 30° is a good compromise between production effort and cooling efficiency. Also coolant fluids with a low molar mass and high specific heat capacity should be preferred because of their low impact on the boundary layer.
96

A Study of the Effects of Turning Angle on Particle Deposition in Gas Turbine Combustor Liner Effusion Cooling Holes

Blunt, Rory Alexander Fabian 23 September 2016 (has links)
No description available.
97

Optical Probe Nacelle for Short Focal Length Diagnostics in High Temperature Supersonic Flows

Ignacio Lasala Aza (20151309) 12 November 2024 (has links)
<p dir="ltr">This work seeks to study a novel, actively cooled aerodynamic probe nacelle with integrated optics to enable short focal length laser diagnostics in high-temperature supersonic flows, especially relevant for Hot Jet wind tunnels. The nacelle has been designed to: i.) survive the thermal loads generated at Mach 6 and total conditions of 1700 K, 44 bar, and ii.) minimize the flow disturbance generated by the front bow shock. By enabling measurements at shorter focal lengths, higher irradiance is achieved at the focal point for the same laser power.</p><p dir="ltr">The thermal survivability of the nacelle is studied first via a 1D conjugate heat transfer model including effusion cooling effects. The coolant pressure predicted by the model is used as boundary condition in 3D Steady RANS numerical simulations, where spatially resolved cooling effectiveness contours are extracted. Flow distortion is also studied from the numerical simulations. Modelling accurately the effusion holes allows to study the coolant jets-bow shock interaction and its effect on the shape of the shock. The distance between the focusing lens and the bow shock is studied and compared to the focal length achieved if the optics were placed outside the facility. The shift in laser trajectory due to refractive index gradients across the flow is predicted using ray propagation models.</p><p dir="ltr">The cooling jacket of the nacelle is tested experimentally in an Open Jet wind tunnel at low supersonic (Mach~1.1), long duration, heated conditions. “In-situ” calibrated infrared thermography is used to obtain temperature and cooling effectiveness contours in the front faces and Atomic Layer Thermopiles (ALTPs) are used to measure heat flux and adiabatic heat transfer coefficient, enabling validation of the numerical models. High-frequency accelerometer data and Camera-Based vibrations data are collected to identify vibration frequencies and peak to peak amplitudes in the nacelle, allowing to correlate them with the momentum of the Open Jet and study their impact on the location of the focal point.</p>
98

Isolement et caractérisation de nouvelles espèces de Torque Teno Mini Virus (TTMV) : implication potentielle dans la pathogenèse de la pneumonie / Isolation and characterization of new species of Torque Teno Mini Virus (TTMV) : potential implication in the pathogenesis of pneumonia

Galmès, Johanna 03 April 2013 (has links)
La pneumonie est la première cause de mortalité chez l’enfant dans le monde. Elle peut être provoquée par un certain nombre d’agents pathogènes connus mais 15 à 35% des pneumonies de l’enfant restent encore non renseignées d’un point de vue étiologique. L’utilisation d’un test moléculaire de découverte de nouveaux pathogènes nous a permis de découvrir de nouvelles espèces de Torque Teno Mini Virus (TTMV, Anelloviridae), nommées TTMV-LY, dans trois épanchements pleuraux provenant d’enfants hospitalisés avec une pleuro-pneumopathie, dont l’étiologie demeurait inconnue. Les TTMV sont des virus ubiquitaires dont l’implication dans une pathologie reste à déterminer. Les voies respiratoires ayant précédemment été décrites pour être un site d'infection des anellovirus, nous avons entrepris de caractériser ces nouveaux virus, ainsi que d’étudier leur potentiel rôle dans la pathogénèse.Les génomes complets de TTMV-LY ont été isolés, caractérisés puis répliqués in vitro. La réponse des cellules épithéliales alvéolaires, ainsi que des cellules présentatrices d’antigènes (CPA), impliquées dans l’inflammation, a été étudiée après infection par les virions néo-synthétisés.Ces travaux ont démontré que : i) les TTMV-LY peuvent coloniser les poumons en profondeur, ii) les cellules pulmonaires sont permissives aux TTMV-LY et permettent une réplication virale efficace, iii) l’infection virale module les réponses cellulaires et immunitaires des cellules pulmonaires en induisant des dérégulations de l’expression génique et la production de médiateurs inflammatoires, iv) les TTMV-LY seraient capables d’interagir avec les CPA et de réguler ainsi différentiellement le processus inflammatoire.L’ensemble de ces résultats ont permis de mettre en évidence une implication potentielle des TTMV-LY dans la pathogénèse des pneumopathies, et souligné la complexité des mécanismes biologiques mis en jeu lors de l’infection par les virus de cette famille. / Pneumonia is the leading cause of death in children worldwide. It can be caused by a number of known pathogens, but 15-35% of childhood pneumonia are still not associated with an etiologic agent. A pathogen discovery assay allowed us to identify new species of Torque Teno Mini Virus (TTMV, Anelloviridae), named TTMV-LY, in three undiagnosed pleural effusions from children hospitalized with parapneumonic empyema. TTMV are ubiquitous orphan viruses, and their involvement in pathogenesis remains unknown. The respiratory tract was previously described to be a site of anellovirus detection. We investigated the role of these new species in the pathogenesis of severe pneumonia.Full-length TTMV-LY genomes were isolated and in vitro replicated. The response of alveolar epithelial cells, and antigen presenting cells (APC), both involved in the inflammation process, was studied after infection with neo-synthesized virions.This study showed for the first time that: i) TTMV-LY can deeply colonize lungs, ii) alveolar epithelial cells are permissive to the TTMV-LY and allow an efficient replication, iii) viral infection modulates cellular and innate immune responses of alveolar epithelial cells, by inducing gene expression deregulations and inflammatory mediators production, iv) TTMV-LY are able to interact with APC and thereby regulate differentially their inflammatory process.All these results allowed to highlight a potential involvement of TTMV-LY in the pathogenesis of severe pneumonia and brought out the complexity of the biological mechanisms taking place during infection by viruses of this family.
99

Análise por meio de ressonância magnética em pacientes sintomáticos da relação entre as alterações ósseas da articulação temporomandibular e derrame articular em função do posicionamento do disco articular / Analysis by magnetic resonance imaging in symptomatic patients of the relationship between bone changes of the temporomandibular joint and joint effusion related to articular disc position

Gil, Cibelle 03 November 2009 (has links)
A articulação temporomandibular (ATM) é considerada a articulação mais complexa do corpo humano. Assim como outras articulações do sistema músculo-esquelético ela pode ser acometida pelas mesmas doenças e desordens, como por exemplo, deslocamentos de disco (DD), doenças articulares degenerativas (osteoartrite OA), artrites inflamatórias e sinovites. Baseado nos laudos obtidos por meio das análises das imagens em norma sagital das ATMs de pacientes sintomáticos encaminhados para a realização de exame por ressonância magnética (RM) foram avaliadas a presença de alterações ósseas das cabeças de mandíbula, eminências articulares e fossas articulares do osso temporal e a presença de derrame articular (DA), decorrentes do posicionamento do disco articular. A amostra foi constituída por 148 ATMs de 74 pacientes sintomáticos. As alterações ósseas ocorreram com mais frequência nas cabeças de mandíbula, com destaque para o aparecimento de osteófitos e erosões nos casos de deslocamento de disco sem redução (DDSR). Os resultados dos testes estatísticos revelaram que as alterações ósseas da cabeça de mandíbula do tipo erosão e osteófito e da eminência articular anterior, assim como a presença do DA estão associadas ao posicionamento do disco articular. / The temporomandibular joint (TMJ) is considered the most complex articulation of the human body. Like other joints of the musculoskeletal system it can be affected by the same diseases and disorders, such as disc displacement, degenerative joint disease (osteoarthritis - OA), inflammatory arthritis and synovitis. Based on reports obtained by the analysis of images in standard sagittal TMJs of symptomatic patients referred for magnetic resonance exam were evaluated the presence of bone changes in the condyle, articular eminence and glenoid fossa, and the presence of joint effusion arising from the positioning of the disc. The sample consisted of 148 TMJs in 74 symptomatic patients. The bone changes occurred more frequently in the condyles, especially the appearance of osteophytes and erosions in cases of disc displacement without reduction. The results of statistical tests revealed that the bone changes of the condyle type erosion and osteophyte and anterior articular eminence, as well as joint effusion are associated with the disc position.
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Avaliação da viabilidade da técnica de acesso ao espaço epicárdico por punção transatrial para ablação epicárdica por catete / Percutaneous transatrial approach to reach the epicardial space for epicardial mapping and ablation

Venancio, Ana Claudia 20 January 2011 (has links)
Fundamentos O acesso percutâneo ao espaço pericárdico pela via transatrial poderia ser uma alternativa ao acesso subxifóide para o mapeamento e ablação de fibras miocárdicas subepicárdicas. O objetivo deste estudo foi avaliar a viabilidade de alcançar o espaço pericárdico normal através do apêndice auricular direito (AAD) por acesso transvenoso. Métodos e Resultados - Um sistema Mullins (8F), originalmente desenvolvido para alcançar o átrio esquerdo (AE) por punção transeptal foi utilizado neste estudo para transfixar o AAD (16) ou AE (1) em 17 suínos, com uma média de 26,9 ± 2,6 kg, e alcançar o espaço pericárdico normal. Um cateter 7F quadripolar com eletrodo distal com 4 ou 8 mm foi introduzido no espaço pericárdico para aplicações de radiofrequência. Em 15 (88%) animais o procedimento foi realizado sem instabilidade hemodinâmica (PA média inicial = 80,4 ± 11.7 mmHg; PA média final = 86,8 ± 9.7 mmHg, p = 0,11). Foi identificado e aspirado derrame pericárdico discreto (28,9 ± 27.6 ml/animal) durante o procedimento. O espaço pericárdico foi acidentalmente acessado por punção do ventrículo direito (VD) em um animal e por punção do anel da valva tricúspide em outro. Ambos apresentaram sangramento xii pericárdico importante e tamponamento cardíaco. Um dispositivo para oclusão do orifício de perfuração foi testado com sucesso em três porcos, dois no AD e um no VD, sem ocorrência de derrame pericárdico significativo. Conclusões O acesso transatrial ao espaço pericárdico pode ser potencialmente útil para mapeamento e ablação de arritmias cardíacas, bem como para drenagem imediata de um tamponamento cardíaco agudo / Background A transvenous access to the pericardial space could provide a convenient route to map and ablate subepicardial myocardial fibers. The aim of this study was to evaluate the feasibility of reaching the normal pericardial space through the right atrial appendage (RAA) by transvenous access. Methods and Results An 8F Mullins system was used to transfix the right atrium (16) and left atrium (1) in 17 pigs with a mean of 26.9 ± 2.6 kg. A 7F quadripolar catheter with 4 or 8 mm distal tip electrode was introduced into the pericardial space to perform epicardial radiofrequency lesions. The pericardial space was successfully reached in 15 (88%) animals without hemodynamic instability (initial mean BP 80.4 ± 11.7 mmHg; final 86.8 ± 9.7 mmHg, p= 0,11). However, a mild pericardial serohemorrhagic effusion was identified and aspirated in all the animals (28.9 ± 27.6 ml/pig) during the procedure. The pericardial space was accidentally accessed through the right ventricle (RV) in one animal and through the tricuspid annulus in another, which presented important pericardial bleeding and cardiac tamponade. The hypothesis that an occlusion device could be useful to close the created atrial xiv orifice was tested successfully in thee pigs (two at RAA and one at RV) and without significant pericardial bleeding. Conclusions The right atrial appendage route might be potentially useful to access the normal pericardial space for mapping and ablating cardiac arrhythmias as well as to drain promptly an acute tamponade

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