Academic literature on the topic 'Impact de plaques'
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Journal articles on the topic "Impact de plaques"
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Barrett, Hilary E., Kim Van der Heiden, Eric Farrell, Frank J. H. Gijsen, and Ali C. Akyildiz. "Calcifications in atherosclerotic plaques and impact on plaque biomechanics." Journal of Biomechanics 87 (April 2019): 1–12. http://dx.doi.org/10.1016/j.jbiomech.2019.03.005.
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Wendorff, Carina, Heiko Wendorff, Andreas Kuehnl, et al. "Impact of sex and age on carotid plaque instability in asymptomatic patients-results from the Munich Vascular Biobank." Vasa 45, no. 5 (2016): 411–16. http://dx.doi.org/10.1024/0301-1526/a000557.
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Abstract. Background: It is still a controversial issue whether carotid endarterectomy (CEA) for asymptomatic carotid stenosis is superior to best medical treatment. The aim of this study was therefore to analyze the impact of sex and age on carotid plaque instability in asymptomatic patients undergoing CEA. Patients and methods: Atherosclerotic plaques from 465 asymptomatic patients with high-grade carotid artery stenosis (2004 - 2013) at the Munich Vascular Biobank were analyzed. Ascertainment of lesion stability/instability was performed on formalin-fixed paraffin-embedded tissue samples using hematoxylin-eosin and elastic van Gieson staining. Unstable plaques were considered lesions with a fibrous cap < 200 µm overlaying lipid-rich atheroma. Results: The average age of the patients was 69.3 ± 8.2 years. Independent of age, asymptomatic men had in total more frequently unstable plaques in contrast to women (41 % versus 52%, p = 0.042). No differences were found in plaque instability between age-related quartiles (< 65, 65- 69, 70 - 74, > 74 years) for female sex (p = 0.422). In men, a continuous increase in plaque instability with age was observed, without achieving statistical significance (p = 0.125). The greatest differences between male and female sex were found in the last quartile (> 74 years), without achieving statistical significance (p = 0.053). The chance of unstable carotid plaques in men was significantly higher than in women (OR = 1.562, p = 0.040). The probability of age-associated quartiles related to the first quartile demonstrated significant increase in plaque instability in the group of 65- to 69-year-old patients (OR 1.867, p = 0.024) and for patients older than 74 years (OR 1.740, p = 0.040). Conclusions: Asymptomatic men had in total more frequently unstable plaques in contrast to women. Thus, male sex seems to be an additional risk factor for ischemic stroke.
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Hirata, Yoko, Noriyuki Sakata, Tooru Inoue, Kotaro Yasumori, Masahiro Yasaka, and Yasushi Okada. "Histopathological features with angiographic correlates of internal carotid artery pseudo-occlusion: impact of plaque compositions." Journal of Neurosurgery 115, no. 2 (2011): 350–58. http://dx.doi.org/10.3171/2011.3.jns101434.
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Object This study describes clinicopathological characteristics of pseudo-occlusion of the internal carotid artery with regard to its possible mechanisms. Methods The authors retrospectively reviewed 17 patients with pseudo-occlusion and 23 with high-grade stenosis (North American Symptomatic Carotid Endarterectomy Trial criteria ≥ 90%, but no collapsed distal internal carotid artery) who underwent carotid endarterectomy. Atherosclerotic risk factors, clinical presentation, angiographic findings, and histological features of plaque obtained from the carotid endarterectomy were investigated and comparisons were made between groups. Results Plaques obtained in the pseudo-occlusion group were significantly more fibrous and less atheromatous than those in the high-grade stenosis group. Old, organized thrombi were more frequently found in pseudo-occlusion group plaques than in high-grade stenosis group plaques. Plaques acquired in the pseudo-occlusion group had 2 different histological features: the presence or absence of the original lumen. The pseudo-occlusion plaques with total occlusion and recanalization (8 patients) were composed of thrombotic total occlusion with lumen recanalization by large neovascular channels, whereas those with severe stenosis (9 patients) were fibrous or fibroatheromatous and had severe stenosis of the original lumen. In patients with pseudo-occlusion and total occlusion and recanalization, the authors observed a significantly higher incidence of transient ischemic attack and anterior communicating artery–posterior communicating artery collateral flow than those with high-grade stenosis and pseudo-occlusion with severe stenosis. Conclusions Plaques of the pseudo-occlusion group were more fibrous than those of the high-grade stenosis group and had 2 different histological features: pseudo-occlusion with total occlusion and recanalization or pseudoocclusion with severe stenosis. This difference in plaque histology may be related to the clinical features of pseudoocclusion, such as symptoms and collateral flow patterns.
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Puylaert, Pauline, Isabelle Coornaert, Cédric H. G. Neutel, et al. "The Impact of RIPK1 Kinase Inhibition on Atherogenesis: A Genetic and a Pharmacological Approach." Biomedicines 10, no. 5 (2022): 1016. http://dx.doi.org/10.3390/biomedicines10051016.
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RIPK1 (receptor-interacting serine/threonine-protein kinase 1) enzymatic activity drives both apoptosis and necroptosis, a regulated form of necrosis. Because necroptosis is involved in necrotic core development in atherosclerotic plaques, we investigated the effects of a RIPK1S25D/S25D mutation, which prevents activation of RIPK1 kinase, on atherogenesis in ApoE−/− mice. After 16 weeks of western-type diet (WD), atherosclerotic plaques from ApoE−/− RIPK1S25D/S25D mice were significantly larger compared to ApoE−/− RIPK1+/+ mice (167 ± 34 vs. 78 ± 18 × 103 µm2, p = 0.01). Cell numbers (350 ± 34 vs. 154 ± 33 nuclei) and deposition of glycosaminoglycans (Alcian blue: 31 ± 6 vs. 14 ± 4%, p = 0.023) were increased in plaques from ApoE−/− RIPK1S25D/S25D mice while macrophage content (Mac3: 2.3 ± 0.4 vs. 9.8 ± 2.4%, p = 0.012) was decreased. Plaque apoptosis was not different between both groups. In contrast, pharmacological inhibition of RIPK1 kinase with GSK’547 (10 mg/kg BW/day) in ApoE−/− Fbn1C1039G+/− mice, a model of advanced atherosclerosis, did not alter plaque size after 20 weeks WD, but induced apoptosis (TUNEL: 136 ± 20 vs. 62 ± 9 cells/mm2, p = 0.004). In conclusion, inhibition of RIPK1 kinase activity accelerated plaque progression in ApoE−/− RIPK1S25D/S25D mice and induced apoptosis in GSK’547-treated ApoE−/− Fbn1C1039G+/− mice. Thus, without directly comparing the genetic and pharmacological studies, it can be concluded that targeting RIPK1 kinase activity does not limit atherogenesis.
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Wang, Bo, Xitan Hou, Yaning Sun, et al. "Interleukin-17A influences the vulnerability rather than the size of established atherosclerotic plaques in apolipoprotein E-deficient mice." Open Life Sciences 17, no. 1 (2022): 1104–15. http://dx.doi.org/10.1515/biol-2022-0072.
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Abstract Interleukin (IL)-17A plays a role in the development of atherosclerotic plaques; however, the mechanism remains unclear. In this study, apolipoprotein E-deficient (ApoE–/–) mice were fed a high-fat diet to induce atherosclerosis, followed by the treatment with exogenous recombinant IL-17A or the neutralizing antibody to confirm the impact of IL-17A on the established atherosclerotic plaques. We found that both the stimulation of IL-17A and blockage of endogenous IL-17 via antibody did not affect the size of the established plaques. However, IL-17A significantly increased the vulnerability of plaques characterized by the accumulation of lipids and T cells with a concurrent decrease in the number of smooth muscle cells. In addition, the blockage by IL-17 neutralizing antibody attenuated plaque vulnerability. Furthermore, we found that although IL-17A did not affect the efferocytosis of macrophages to apoptotic cells, it promoted the apoptosis of macrophages in the presence of oxidized low-density lipoprotein in vitro. Also, IL-17A upregulated chemokines MCP-1 and CXCL-10 expression in the plaques. Our data indicated that IL-17A controlled both SMC and macrophage accumulation and the apoptosis within the plaque, which may further weaken the aorta wall. This study suggests that IL-17A may be a potential therapeutic target for cardiovascular diseases.
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Peiu, Sorin Nicolae, Diana Gabriela Iosep, Mihai Danciu, Veronica Scripcaru, Victor Ianole, and Veronica Mocanu. "Ghrelin Expression in Atherosclerotic Plaques and Perivascular Adipose Tissue: Implications for Vascular Inflammation in Peripheral Artery Disease." Journal of Clinical Medicine 13, no. 13 (2024): 3737. http://dx.doi.org/10.3390/jcm13133737.
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Atherosclerosis, a leading cause of peripheral artery disease (PAD), is driven by lipid accumulation and chronic inflammation within arterial walls. Objectives: This study investigates the expression of ghrelin, an anti-inflammatory peptide hormone, in plaque morphology and inflammation in patients with PAD, highlighting its potential role in age-related vascular diseases and metabolic syndrome. Methods: The analysis specifically focused on the immunohistochemical expression of ghrelin in atherosclerotic plaques and perivascular adipose tissue (PVAT) from 28 PAD patients. Detailed immunohistochemical staining was performed to identify ghrelin within these tissues, comparing its presence in various plaque types and assessing its association with markers of inflammation and macrophage polarization. Results: Significant results showed a higher prevalence of calcification in fibro-lipid plaques (63.1%) compared to fibrous plaques, with a notable difference in inflammatory infiltration between the two plaque types (p = 0.027). Complicated plaques exhibited increased ghrelin expression, suggesting a modulatory effect on inflammatory processes, although this did not reach statistical significance. The correlation between ghrelin levels and macrophage presence, especially the pro-inflammatory M1 phenotype, indicates ghrelin’s involvement in the inflammatory dynamics of atherosclerosis. Conclusions: The findings propose that ghrelin may influence plaque stability and vascular inflammation, pointing to its therapeutic potential in managing atherosclerosis. The study underlines the necessity for further research to clarify ghrelin’s impact on vascular health, particularly in the context of metabolic syndrome and age-related vascular alterations.
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Mouzakis, Dionysios E., Tapio Harmia, and József Karger-Kocsis. "Fracture Behaviour of Discontinuous Long Glass Fibre Reinforced Injection Moulded Polypropylene." Polymers and Polymer Composites 8, no. 3 (2000): 167–75. http://dx.doi.org/10.1177/0967391120000803167.
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The in- and out-of-plane fracture behaviour of injection-moulded discontinuous long glass fibre reinforced (DLGF) polypropylene composites (PP) as stu.died. The DLGF content (0-11 wt%) and thickness of the molded plaques were vaned. The m-plane fracture toughness, as assessed by the essential work of fracture (EWF) method, showed a clear anisotropy. This was explained by the effects of the DLGF orientation and distribution. confirmed by fractography. The out-of-plane instrumented falling weight impact (IFWI) toughness ofthe 4 mm thick plaques was higher than that of the 2 mm thick ones. This was attributed to the onset of shear fracture, supported by the DLGF alIgnment across the plaque thickness in the thicker plaques.
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Seime, Till, Max van Wanrooij, Eva Karlöf, et al. "Biomechanical Assessment of Macro-Calcification in Human Carotid Atherosclerosis and Its Impact on Smooth Muscle Cell Phenotype." Cells 11, no. 20 (2022): 3279. http://dx.doi.org/10.3390/cells11203279.
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Intimal calcification and vascular stiffening are predominant features of end-stage atherosclerosis. However, their role in atherosclerotic plaque instability and how the extent and spatial distribution of calcification influence plaque biology remain unclear. We recently showed that extensive macro calcification can be a stabilizing feature of late-stage human lesions, associated with a reacquisition of more differentiated properties of plaque smooth muscle cells (SMCs) and extracellular matrix (ECM) remodeling. Here, we hypothesized that biomechanical forces related to macro-calcification within plaques influence SMC phenotype and contribute to plaque stabilization. We generated a finite element modeling (FEM) pipeline to assess plaque tissue stretch based on image analysis of preoperative computed tomography angiography (CTA) of carotid atherosclerotic plaques to visualize calcification and soft tissues (lipids and extracellular matrix) within the lesions. Biomechanical stretch was significantly reduced in tissues in close proximity to macro calcification, while increased levels were observed within distant soft tissues. Applying this data to an in vitro stretch model on primary vascular SMCs revealed upregulation of typical markers for differentiated SMCs and contractility under low stretch conditions but also impeded SMC alignment. In contrast, high stretch conditions in combination with calcifying conditions induced SMC apoptosis. Our findings suggest that the load bearing capacities of macro calcifications influence SMC differentiation and survival and contribute to atherosclerotic plaque stabilization.
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Ulrich, Jason D., Tyler K. Ulland, Thomas E. Mahan, et al. "ApoE facilitates the microglial response to amyloid plaque pathology." Journal of Experimental Medicine 215, no. 4 (2018): 1047–58. http://dx.doi.org/10.1084/jem.20171265.
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One of the hallmarks of Alzheimer’s disease is the presence of extracellular diffuse and fibrillar plaques predominantly consisting of the amyloid-β (Aβ) peptide. Apolipoprotein E (ApoE) influences the deposition of amyloid pathology through affecting the clearance and aggregation of monomeric Aβ in the brain. In addition to influencing Aβ metabolism, increasing evidence suggests that apoE influences microglial function in neurodegenerative diseases. Here, we characterize the impact that apoE has on amyloid pathology and the innate immune response in APPPS1ΔE9 and APPPS1-21 transgenic mice. We report that Apoe deficiency reduced fibrillar plaque deposition, consistent with previous studies. However, fibrillar plaques in Apoe-deficient mice exhibited a striking reduction in plaque compaction. Hyperspectral fluorescent imaging using luminescent conjugated oligothiophenes identified distinct Aβ morphotypes in Apoe-deficient mice. We also observed a significant reduction in fibrillar plaque–associated microgliosis and activated microglial gene expression in Apoe-deficient mice, along with significant increases in dystrophic neurites around fibrillar plaques. Our results suggest that apoE is critical in stimulating the innate immune response to amyloid pathology.
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Grootaert, Mandy O. J., Dorien M. Schrijvers, Marthe Hermans, Viviane O. Van Hoof, Guido R. Y. De Meyer, and Wim Martinet. "Caspase-3 Deletion Promotes Necrosis in Atherosclerotic Plaques of ApoE Knockout Mice." Oxidative Medicine and Cellular Longevity 2016 (2016): 1–11. http://dx.doi.org/10.1155/2016/3087469.
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Apoptosis of macrophages and vascular smooth muscle cells (VSMCs) in advanced atherosclerotic plaques contributes to plaque progression and instability. Caspase-3, a key executioner protease in the apoptotic pathway, has been identified in human and mouse atherosclerotic plaques but its role in atherogenesis is not fully explored. We therefore investigated the impact of caspase-3 deletion on atherosclerosis by crossbreeding caspase-3 knockout (Casp3−/−) mice with apolipoprotein E knockout (ApoE−/−) mice. Bone marrow-derived macrophages and VSMCs isolated from Casp3−/−ApoE−/−mice were resistant to apoptosis but showed increased susceptibility to necrosis. However, caspase-3 deficiency did not sensitize cells to undergo RIP1-dependent necroptosis. To study the effect on atherosclerotic plaque development, Casp3+/+ApoE−/−and Casp3−/−ApoE−/−mice were fed a western-type diet for 16 weeks. Though total plasma cholesterol, triglycerides, and LDL cholesterol levels were not altered, both the plaque size and percentage necrosis were significantly increased in the aortic root of Casp3−/−ApoE−/−mice as compared to Casp3+/+ApoE−/−mice. Macrophage content was significantly decreased in plaques of Casp3−/−ApoE−/−mice as compared to controls, while collagen content and VSMC content were not changed. To conclude, deletion of caspase-3 promotes plaque growth and plaque necrosis in ApoE−/−mice, indicating that this antiapoptotic strategy is unfavorable to improve atherosclerotic plaque stability.
Dissertations / Theses on the topic "Impact de plaques"
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Fluteau, Frédéric. "Impact de la tectonique des plaques sur le climat." Paris 7, 1999. http://www.theses.fr/1999PA077090.
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A l'echelle des temps geologiques, le climat est controle par plusieurs facteurs. L'un de ceux-ci est la tectonique des plaques. Nous en estimons l'impact par des simulations climatiques ou un modele de circulation generale atmospherique est force par une reconstruction de la position des continents, une restitution des reliefs et des terres emergees. Notre etude s'est focalisee sur trois periodes geologiques : la fin du tertiaire (0-30 ma), le cretace moyen (94-120 ma), et le permien superieur (255 ma). Pour la fin du tertiaire, nous avons etudie l'influence des changements paleogeographiques sur les moussons d'asie et d'afrique. Nous observons : 1) un deplacement progressif de la mousson d'ete de l'indochine vers les reliefs himalayens. 2) la forte influence du retrait d'une mer epicontinentale (la paratethys) sur la mousson d'asie. 3) la desertification du nord de l'afrique. L'evolution du climat simule nous permet de mieux contraindre l'evolution sedimentaire du golfe du bengale. Au cretace, nous avons etudie l'influence de la transgression marine et de la dispersion generalisee des continents issus du gondwana entre l'aptien et le cenomanien. La transgression s'avere etre la cause d'un important changement climatique qui se traduit par une baisse de l'amplitude thermique annuelle. La dispersion du gondwana induit egalement un changement climatique, permettant d'expliquer l'evolution regionale de la vegetation. L'utilisation d'un faible gradient thermique oceanique pole-equateur, plus coherent avec les donnees, permet de mieux simuler les climats septentrionaux. Pour le permien superieur, nous avons etudie l'impact sur le climat de differentes configurations de la pangee. Le climat simule apparait etre en excellent accord avec les donnees paleoclimatiques. Neanmoins, des ecarts regionaux entre climats simules et donnees nous permettent de discuter le difficile probleme des paleoelevations des chaines des appalaches et varisque a la fin de l'orogenese hercynienne.
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Nême, Alain. "Comportement de plaques épaisses à l'impact de cylindres : modélisation du comportement de la plaque." Cachan, Ecole normale supérieure, 1994. http://www.theses.fr/1994DENS0007.
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Le blindage des véhicules joue un rôle important pour la sécurité des personnes transportées. Nous donnons, par ce travail, les moyens d'effectuer un premier dimensionnement de l'épaisseur d'un blindage métallique soumis à l'impact normal d'un cylindre également métallique. Avant d'aboutir a ce résultat, nous avons étudié ce problème en développant, sur la base de travaux existants, un modèle analytique simplifie fonde sur l'optimisation d'un champ de vitesse paramétré représentant l'écoulement plastique de la cible autour du projectile. Cependant les résultats peu probants concernant la pénétration dans un massif semi-infini, nous ont conduits à utiliser une simulation numérique (code efhyd2d) afin d'analyser le problème complet de la perforation de plaques d'épaisseurs finies. L'une des principales difficultés était la détermination d'un critère de ruine de la cible. Nous avons choisi de la représenter par une bifurcation d'équilibre. Cette approche est décomposée de sorte qu'il soit possible d'analyser d'autres problèmes de structures que celui de l'impact. Un développement détaillé est dévolu à l'étude des bifurcations d'équilibre de trois matériaux élastoplastique, a savoir l'acier à blindage (26ncd6), le 2017 (au4g) et le 5083 (ag5). Cependant notre validation expérimentale est limitée aux vitesses d'impacts inferieures à 360 m/s. Afin d'être par la suite en mesure de traiter des problèmes comportant des matériaux de faible diffusivité thermique impactes a des vitesses de 1000 a 2000 m/s, nous développons dans cette étude deux types de comportement thermoélastoplastique et thermoélastoviscoplastique isotrope, en accord avec les principes de la thermodynamique macroscopique. De plus nous vérifions que ces lois constitutives représentent correctement les essais de hautes pressions sur aluminium, cuivre et monocristal de zinc. Ce travail est la première étape dans l'identification complète de ces modèles phénoménologiques et leur introduction dans un code de calcul, ainsi que dans le développement du critère de bifurcation (autres types de comportements, étude de la stabilité du champ bifurquant etc. )
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Cozic, Roger. "Contribution à l'étude du comportement dynamique de matériaux par impact plaque sur plaque." Nantes, 1994. http://www.theses.fr/1994NANT2045.
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Cette étude expérimentale par impact plaque sur plaque contribue à la compréhension de l'endommagement par ondes de choc courtes des matériaux composites dans une déformation plane de faible valeur (inferieure a 10%). Elle comporte la réalisation d'une technique dite canon électrothermique basée sur l'explosion d'une feuille mince d'aluminium; celle-ci propulse un projectile en forme d'étoile sur un matériau à étudier, lui confinant une zone octogonale de déformation plane. La mesure interferométrique effectuée par laser sur la face avant du matériau donne accès par l'obtention de la vitesse des particules et grâce à la connaissance de celle du projectile impactant la face arrière, à la relation contrainte-déformation en dynamique pour des vitesses de déformation dans la gamme de 8. 10#3 s##1 a 5. 10#4 s##1. Les matériaux étudiés sont de deux types: des composites à fibres de verre et matrice organique d'une part, et des composites carbone/carbone de différentes structures d'autre part. L'analyse comparative des résultats conduit à des relations linéaires de la variation de contrainte en fonction de la vitesse de déformation. De plus une observation au microscope à balayage permet de mettre en évidence des décohésions entre les torons de fibres et la matrice, ainsi qu'entre les fibres elle-mêmes.
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Pyrzowski, Lukasz. "Analyse visco-plastique de l'endommagement des plaques et coques soumises aux impacts." Phd thesis, Université d'Orléans, 2010. http://tel.archives-ouvertes.fr/tel-00608054.
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Le travail concerne le comportement des plaques et coques soumises à des charges dynamiques dues à des explosions des mélanges gazeux. Des problèmes mécaniques d'apparition des fissures et d'endommagement ductile sont analysés. En introduction, la revue de la littérature a été présentée ainsi que les théories actuellement les plus souvent utilisées dans ce domaine. Une brève description des outils numériques qui ont servi dans l'étude a été également donnée. Les essais expérimentaux et les résultats des mesures ont été discutés dans la deuxième partie du mémoire. Ils ont permis d'identifier les paramètres matériels du modèle constitutif viscoplastique et d'endommagement nécessaires pour mener une analyse numérique du comportement des plaques, de faire la vérification des nombreuses simulations discutées à la fin du travail. Dans les conclusions, est présenté le bilan des modélisations en exposant surtout celles qui ont conduit à de meilleurs résultats.L'auteur discute les hypothèses utilisées, les limitations du modèle et esquisse desperspectives et l'évolution possible à l'avenir.
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Diop, Samory. "Caractérisation d'un choc et de l'état vibratoire d'une structure épaisse soumise à un impact." Le Mans, 1990. http://www.theses.fr/1990LEMA1007.
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Cette étude se situe dans le cadre de la surveillance acoustique du circuit primaire des réacteurs à eau pressurisée (REP). La présence de débris ou objets vagabonds encore appelés corps errants peut mettre en jeu la disponibilité d'une tranche nucléaire. Le but de l'étude est d'évaluer les risques de dégradation des structures internes du réacteur avant arrêt de la tranche. L'état vibratoire d'une plaque plane soumise à un choc est étudié, on cherche à identifier la source d'impact. Ces travaux se sont appuyés sur la théorie de Hertz et sur des simulations numériques modèlisant l'état vibratoire de la structure à l'aide de la théorie des rais généralisés. Un code de calcul a été écrit pour simuler des signaux d'impact et discriminer les paramètres de forme caractéristiques de la localisation de l'impact et de la masse de l'objet percutant: temps de montée du signal, attenuation géométrique, amplitude réelle, période principale excitée. Une maquette reproduisant des impacts sur une structure immergée a été realisée pour valider le code de calcul, les résultats des simulations et construire des abaques (temps de montée/distance source-capteur), (amplitudes/énergie), (temps de contact/énergie) en fonction des masses des objets percutants. Les travaux ont abouti à la mise au point d'une méthodologie de diagnostic qui, partant de l'acquisition d'un signal par un capteur, donne la localisation, la masse et l'énergie d'impact d'un objet percutant la paroi où est fixé le capteur.
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Kolopp, Amélie. "Impact sur structures sandwiches pour application de blindage aéronautique." Toulouse 3, 2012. http://thesesups.ups-tlse.fr/1774/.
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Les structures sandwiches sont pressenties en tant que solution de protection potentielle des structures aéronautiques soumises à l'impact. De fait, elles allient un bon rapport rigidité/masse avec des capacités d'absorption d'énergie. Le travail de thèse s'inscrit dans le cadre du projet ANR MANSART (Matériaux sANdwicheS ARchiTecturés) et s'intéresse en particulier au comportement de sandwichs à l'impact. Le travail effectué se déroule de manière incrémentale, partant de l'étude expérimentale d'un large choix de structures sandwiches, pour aboutir à l'identification des solutions plus prometteuses. Des plaques aluminium, assemblages de tissus, interlocks et composites ont été testés en tant que peau avant et combinés avec différents types de cœurs : nids d'abeille, mousse, architectures de fibres, etc. Les structures sont retenues sur les critères de non-perforation à masse et déformation minimale, pour un type d'impact donné (120 m/s, 1 kJ). Parmi les structures testées, on retiendra les plaques aluminium et les assemblages de tissus pour les peaux et le nid d'abeille aluminium pour le cœur. Ces trois structures sont étudiées plus en détail au travers de modèles numériques, afin de compléter les données d'essai et la compréhension des mécanismes en jeu, en vue de futures études d'optimisation numériques. Cette étude a permis d'identifier des effets dynamiques dans les matériaux et de couplage peaux-cœur dans le sandwich. Ces deux aspects pilotent résistance à la perforation de la structure. Ainsi, la confrontation des résultats numériques et expérimentaux et l'identification de paramètres clés ont permis de proposer des pistes de choix pour le design de blindages<br>Sandwich structures are foreseen as potential armour architectures for aircraft structures subjected to impacts. Indeed, these structures are characterized by their good weight-specific bending stiffness as well as their energy absorption capabilities. This work is part of the MANSART project (Architectured Sandwich Materials), and aims to characterize the behaviour of sandwich structures against impacts. The present work starts with the experimental study of a large range of sandwich structures to come to the identification and study of the most promising solutions. Aluminium plates, fabrics, interlocks and composite structures have been tested as front skin, combined with several types of cores: honeycombs, foam, fibres assemblies, etc. The structures have been selected considering several criteria (no perforation with a minimal weight and residual deformation of the structure) for a given set of impact parameters (120 m/s, 1 kJ of initial kinetic energy). Aluminium plates and dry aramid fabrics stitched together have been selected as potential front skin, and aluminium honeycomb as sandwich core. These three structures have been further studied through numerical modelling, to complete the experimental data and the understanding of the main mechanisms occurring during the impact. Strain rate sensitivity of materials, as well as skins-core coupling effects have been identified as important mechanisms, which drive the resistance against the perforation of the structures. Ways of improvement for the armour design are proposed, based on the numerical /experimental results confrontation and the key parameters identification
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Quirion, Yann. "Impact sur matériaux métalliques : modélisation des phénomènes de rupture." Nantes, 2003. http://www.theses.fr/2003NANT2103.
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Notre étude contribue au développement de simulations numériques fiables permettant l'identification de lois de vulnérabilité empiriques. Nous souhaitons prédire lors de l'impact d'éclats métalliques sur plaques métalliques, la perforation de la cible ainsi que la fragmentation du projectile et de la cible. Ces phénomènes de rupture sont représentés par des conditions de bifurcation en vitesse dans l'équilibre thermomécanique. Un modèle Thermo Elastique Plastique Viscoplastique (TEPV) est développé et identifié. Deux variables distinctes sont choisies pour décrire la plasticité et la viscoplasticité. La loi de comportement TEPV et le critère de bifurcation sont implémentés dans le code de calcul ABAQUS/Explicit. Un schéma temporel explicite couplé avec un critère de convergence de sous-incrémentation est employé. Les résultats de simulation sont compatibles avec les observations expérimentales pour des impacts à 1000 m/s à incidence normale et oblique (45ʿ)<br>Our work contributes to the substitution of expensive trials by reliable simulations allowing the identification of empirical laws of vulnerability. In particular, we want to predict, in case of metallic fragments impact on metallic plates, the perforation of the target as well as the fragmentation of the projectile and the target. We choose to represent these rupture phenomena by loss of uniqueness for the solution of the thermomechanical balance equation. A Thermo Elastic Plastic Viscoplastic (TEPV) model is developed and identified. Two separated variables are introduced to describe plasticity on the one hand and viscoplasticity on the other hand. These two issues are implemented in the finite elements code ABAQUS/Explicit. An explicit scheme with a convergence criterion of sub-incrementation is used to integrate the strain rate. The simulation results confirm the experimental tendencies for impacts at 1000 m/s with normal and slant incidence (45ʿ)
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Alnabhani, Ziad. "Impact du gène NOD2 sur l'homéostasie du microbiote et de la muqueuse intestinale." Paris 7, 2013. http://www.theses.fr/2013PA077164.
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La maladie de Crohn (MC) est une maladie inflammatoire chronique de l'intestin. Sa physiopathologie est caractérisée par une réaction immunitaire excessive en réponse à des anomalies du microbiote chez des individus génétiquement prédisposés. Bien que les mutations du gène NOD2 aient été associées à la MC, leur rôle dans la genèse de la maladie reste inconnu. Nod2 est un récepteur intracellulaire au muramyl dipeptide, un fragment du peptidoglycane des bactéries Gram positif et Gram négatif. Les objectifs de thèse étaient d'étudier l'impact de Nod2 sur le microbiote et la fonction de la muqueuse digestive. Nous avons montré que les souris déficientes pour Nod2 présentaient des altérations du microbiote intestinal et que ces altérations étaient indépendantes des facteurs environnementaux. La dysbiose bactérienne liée à l'absence de Nod2 n'était pas capable d'affecter la fonctionnalité de l'épithélium intestinal. Nous avons montré que l'expression de Nod2 dans les cellules épithéliales contrôlait la stabilité du microbiote en modulant l'expression des peptides antimicrobiens. A l'inverse, Nod2 dans le compartiment immunitaire régulait les fonctions de l'épithélium. Nous avons observé que l'absence de Nod2 dans les lymphocytes T-CD4+ était suffisante pour altérer la perméabilité intestinal. Cependant, l'activation de Nod2 par son ligand dans les cellules épithéliales était capable de normaliser la perméabilité. Enfin, nous avons montré que Nod2 protégeait l'intestin grêle en cas d'inflammation colique. L'ensemble de ces résultats apporte de nouveaux éléments dans la connaissance des mécanismes par lesquels les mutations du gène Nod2 participent au développement de la MC<br>Crohn disease (CD) is a chronic inflammatory bowel disease characterized by an excessive immune reaction in response to abnormal microbiota in genetically predisposed individuals. Although NOD2 mutations have been associated with susceptibility to CD, their role in the genesis of the human disease remains unclear. Nod2 is a sensor of muramyl dipeptide that is the minimal bioactive peptidoglycan fragment from both Gram positive and Gram negative bacteria. Numerous studies have shown that Nod2 deficiency alters microbiota composition and the homeostasis of the intestinal mucosa. The aims of this thesis were to study the role of Nod2 inside immune and epithelial compartment in the control of the gut microbiota and mucosal homeostasis using animal and cellular models. We have shown Nod2 Knockout mice exhibited a microbiota dysbiosis at both ileal and colonic location and that these alterations of intestinal microbiota were independent of environmental factors. Nod2 inside hematopoietic lineage regulated the barrier function. However, Nod2 deficiency inside epithelial compartment maintained the bacterial dysbiosis by regulating the secretion of both mucins and antimicrobial peptides. Among immune cells, we have also shown that Nod2 deficiency in C134+ T cells was sufficient to modify the intestinal barrier function. Nevertheless, activation of Nod2 by their ligands normalized the increase of permeability induced by CD4+ T cells by MLCK-dependent mechanisms. Finally, we demonstrated that Nod2 protected the small intestine against colitis. Taken together, these results provide new evidence in favor of the mechanism by which NOD2 mutations are involved in the pathogenesis of CD
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Smaoui, Mourad. "Nouvelle modélisation multiparticulaire pour l'analyse des efforts dans les plaques composites multicouches impactées." Phd thesis, Ecole Nationale des Ponts et Chaussées, 1996. http://tel.archives-ouvertes.fr/tel-00529386.
Full textAbstract:
On propose une modélisation numérique des plaques multicouches en matériaux composites lorsqu'elles sont soumises à l'impact de charges dynamiques. Cette modélisation permet de déterminer les efforts engendrés par l'impact, le but étant de pouvoir étudier certains endommagements comme le délaminage. La nouvelle modélisation utilisée appelée modélisation multiparticulaire des matériaux multicouches (M4), permet de modéliser l'objet tridimensionnel par une géométrie bidimensionnelle tout en augmentant le nombre de champs cinématiques. Elle fait apparaître de manière naturelle des efforts au niveau des interfaces entre les couches. Ces efforts peuvent être reliés au phénomène de délaminage. L'analyse des résultats de la littérature permet de montrer que cette modélisation est pertinente dans le cas des chocs relativement rapides. Un outil numérique a été réalisé sur la base de la méthode des éléments finis en dynamique. Le code éléments finis obtenu est ensuite validé, puis appliqué à l'analyse des efforts dans une plaque multicouche impactée. Nous montrons sur un exemple, la pertinence de cette modélisation et sa capacité à fournir de manière simple et rapide, des informations utiles pour l'étude des différents aspects du délaminage (initiation, propagation, étendue).
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Espinosa, Christine. "Contribution à l'étude du comportement sous impact localisé basse vitesse de plaques stratifiées à base d'unidirectionnels composites à fibres longues." Bordeaux 1, 1991. http://www.theses.fr/1991BOR10617.
Full textAbstract:
L'objet de cette etude est la simulation numerique de l'endommagement subi par des plaques stratifiees a base d'unidirectionnels carbone/ou verre/epoxyde pendant et apres un impact localise de faible energie. Nous identifions et caraterisons les parametres typiques concernant le montage experimental, la sollicitation, le comportement de structure et les processus d'endommangement, puis nous reconstituons une chronologie de l'endommagement en parallele avec celles de la sollicitation et de la reponse de la plaque. L'analyse de l'adaptabilite des modeles theoriques actuels a la modelisation des quatre points precedents nous permet de choisir et de developper une technique auto-coherente de modelisation de l'endommagemenmt de fissuration caracteristique de l'impact. Nous developpons le code dynamique explicite par elements finis plexus a la simulation du comportement de materiau composite vierge et endommage. Enfin, nous discutons le paradoxe numerique de representation du comportement de structure de la plaque et du materiau heterogene dispersif endommageable
Books on the topic "Impact de plaques"
1
Bauer, Helmut. Multiple Sclerosis: Its Impact from Childhood to Old Age (Mpn 26). W.B. Saunders Company, 1993.
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2
Major impacts and plate tectonics: A model for the Phanerozoic evolution of the earth's lithosphere. Routledge, 2001.
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3
Major Impacts and Plate Tectonics: A Model for the Phanerzoic Evolution of the Earth's Lithospehere. Taylor & Francis, 2000.
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4
Major Impacts and Plate Tectonics: A Model for the Phanerzoic Evolution of the Earths Lithosphere. Taylor & Francis Group, 2023.
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5
Saraiya, Ami, Deep Joshipura, and Alice Gottlieb. Psoriasis treatment. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780198737582.003.0026.
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Psoriasis is an immune-mediated skin disease that is associated with various factors, including genetics, stress, infections, and environmental triggers. Numerous treatment options exist for plaque psoriasis including topical therapy, phototherapy, systemic therapy, and biological therapy. In order to select a treatment for a patient, a clinician must consider many aspects. First, one must assess the impact and burden of the disease on a patient as well as a patient’s expectations from therapy. Other important factors to consider include the severity of skin disease, location of psoriatic plaques, comorbidities and presence of psoriatic arthritis, efficacy of different treatments, potential side-effects, safety, and cost. In this chapter, an evidence-based review is presented on the treatment armamentarium for psoriasis as well as new biological treatments and those under investigation. In order to guide practitioners, several treatment algorithms are provided and others are referenced from the literature.
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Granacher, Robert P. Behavioral Neurological Aspects Involving the Elderly and the Law. Oxford University Press, 2017. http://dx.doi.org/10.1093/med/9780199374656.003.0003.
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Behavioral neurology has classically encompassed deficit disorders (those with negative symptoms), such as the aphasias, the amnesias, the agnosias, and the apraxias. The focus of this chapter is to explain those focal neurobehavioral syndromes of interest to forensic psychiatrists. These are syndromic disorders with significant behavioral neurological impact. The focal neurobehavioral syndromes covered here generally involve disconnections in gray matter regions, but most of these disorders also imply white matter pathology and include cerebral stroke, neoplasia, and demyelination plaques interrupting neural networks to produce deficit syndromes with negative symptoms. Most issues in the forensic psychiatry of the elderly involve capacity to willfully act (competency), capacity to understand (criminal issues, contractual issues, testamentary capacity), capacity to be aware and protect oneself (elder abuse, personal safety, ability to live alone), and capacity to behave according to societal norms (criminal responsibility, fitness for duty, sexual crimes, dangerousness). A portion of these behaviors are an output of executive function.
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Rosen, Cheryl F., and Brian Kirby. Psoriasis: skin and nails. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780198737582.003.0009.
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Psoriasis is seen in many patients with psoriatic arthritis. It forms part of the CASPAR criteria for establishing the diagnosis of psoriatic arthritis (PsA). The psoriasis accompanying PsA may be mild or quite severe, with a very large impact on quality of life. The presence of cutaneous disease may alter the treatment of a patient’s PsA. Psoriasis affects up to 2–3% of the population of Europe, the United States and Canada. The majority of patients have chronic plaque psoriasis (80%). Other clinical phenotypes include guttate psoriasis, erythrodermic psoriasis, inverse psoriasis, sebopsoriasis and pustular subtypes including generalized pustular psoriasis. Nail involvement is a frequent occurrence and indicate an increased risk of developing psoriatic arthritis. In this chapter, the different psoriatic phenotypes are described as well as the histology and, briefly, the pathophysiology of psoriasis. Environmental factors that can impact psoriasis are reviewed.
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Marques, Marcia Alessandra Arantes, ed. Avanços Científicos em Medicina 3. Bookerfield Editora, 2022. http://dx.doi.org/10.53268/bkf22040500.
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Este livro reúne trabalhos científicos relevantes em Ciências Médicas. Decidiu-se pela divisão em quatro seções: i) área básica; ii) área clínica; iii) medicina diagnóstica; iv) área cirúrgica. Pelo primeiro capítulo são abordados os significativos avanços na qualidade dos conhecimentos acerca da anatomia humana, bem como nas técnicas de preservação dos corpos, nos métodos de estudo e nas formas de intervenção cirúrgicas, permitindo aos profissionais a aquisição de conhecimento, visando a realização de procedimentos cada vez mais seguros, minimamente invasivos e naturalmente, menos danosos aos pacientes, possibilitando assim uma recuperação pós-cirúrgica em menor tempo. Por meio do segundo capítulo são apresentadas algumas das mais recentes tendências da evolução do conhecimento na área da motricidade humana, segundo as diretrizes estabelecidas em 2017 pelo American College of Sports Medicine, que bem demostra a importância atribuída ao exercício físico na saúde. Pelos capítulos terceiro e quarto foi avaliado o tratamento cirúrgico da fibrilação atrial crônica com US em pacientes com lesão valvar mitral, considerando-se caracterização clínica pré-operatória e acompanhamento desses pacientes no pós-operatório imediato, na alta hospitalar e tardio até 60 meses. Concluindo-se que o tratamento cirúrgico da FAC com US concomitante e a cirurgia valvar mitral é factível e satisfatório, com manutenção do ritmo sinusal na maioria dos pacientes (83,8%), após 60 meses de seguimento. O quinto capítulo trata da comparação do potencial evocado auditivo cortical P1 em neonatos e lactentes nascidos a termo e pré-termo. A utilização do potencial evocado auditivo cortical P1 em crianças destaca-se pela verificação da maturação auditiva e pesquisa dos níveis mínimos de respostas corticais. Concluiu-se que o nível mínimo de resposta cortical foi maior para os nascidos pré-termo durante o primeiro mês de vida, e a latência do potencial P1 foi maior para os nascidos pré-termo avaliados até o terceiro mês de vida. Por meio do sexto capítulo, foi estudada a segurança e eficácia de formulações intraoculares contendo Luteína e Zeaxantina, isolada ou combinada com Azul Brilhante ou Azul de Trypan em cirurgia de catarata e vitreorretiniana. O sétimo capítulo trata do diagnóstico precoce da púrpura trombocitopênica trombótica. Diante de seu grave curso e, por muitas vezes estar associada a outros distúrbios hematológicos, o diagnóstico precoce é essencial a fim de melhor definir o prognóstico e a terapêutica adequada. Entre os métodos de diagnóstico laboratorial, a técnica de citometria de fluxo tem mostrado melhor eficácia, devido a sua sensibilidade e especificidade. Pelo presente capítulo foi investigada a presença de ensaios clínicos os quais utilizam a citometria de fluxo como método preferencial para o diagnóstico da PTT a fim de realizar uma reflexão do impacto sobre o desfecho clínico da doença. Por meio do oitavo capítulo é buscada a detecção precoce de neoplasias malignas via biomarcadores tumorais, considerada alternativa promissora, especialmente quando associada a tecnologias inovadoras passíveis de miniaturização. A técnica de Phage Display permite selecionar peptídeos ligantes aos mais diversos alvos, superando a heterogeneidade dos tumores e abrindo caminhos para a evolução das práticas clínicas. Neste capítulo, são abordados os principais aspectos relacionados a tumores e os atuais desafios no diagnóstico da doença, bem como a utilização da técnica de Phage Display na descoberta de novos biomarcadores. Pelo nono capítulo foi realizada a avaliação de biomarcadores em mulheres com dor associada à endometriose. Ambos os tratamentos trouxeram benefícios aos pacientes e a redução dos biomarcadores não foi correlacionada à melhora dos escores de dor pélvica e dismenorreia. Pelo décimo capítulo foram selecionados pacientes submetidos a abdominoplastia e mamoplastia os quais receberam a aplicação de Plasma Rico em Plaquetas (PRP) diretamente na cicatriz e comparando-o com o segmento cicatricial oposto sem PRP. Concluiu-se que o uso intradérmico do PRP, apresentou-se promissor, contribuindo beneficamente na evolução do processo cicatricial, com melhores resultados aos 4 dias e 90 dias de pós-operatório.
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Marques, Marcia Alessandra Arantes, ed. Avanços Científicos em Medicina 3. Bookerfield Editora, 2022. http://dx.doi.org/10.53268/bkf22040500.
Full textAbstract:
Este livro reúne trabalhos científicos relevantes em Ciências Médicas. Decidiu-se pela divisão em quatro seções: i) área básica; ii) área clínica; iii) medicina diagnóstica; iv) área cirúrgica. Pelo primeiro capítulo são abordados os significativos avanços na qualidade dos conhecimentos acerca da anatomia humana, bem como nas técnicas de preservação dos corpos, nos métodos de estudo e nas formas de intervenção cirúrgicas, permitindo aos profissionais a aquisição de conhecimento, visando a realização de procedimentos cada vez mais seguros, minimamente invasivos e naturalmente, menos danosos aos pacientes, possibilitando assim uma recuperação pós-cirúrgica em menor tempo. Por meio do segundo capítulo são apresentadas algumas das mais recentes tendências da evolução do conhecimento na área da motricidade humana, segundo as diretrizes estabelecidas em 2017 pelo American College of Sports Medicine, que bem demostra a importância atribuída ao exercício físico na saúde. Pelos capítulos terceiro e quarto foi avaliado o tratamento cirúrgico da fibrilação atrial crônica com US em pacientes com lesão valvar mitral, considerando-se caracterização clínica pré-operatória e acompanhamento desses pacientes no pós-operatório imediato, na alta hospitalar e tardio até 60 meses. Concluindo-se que o tratamento cirúrgico da FAC com US concomitante e a cirurgia valvar mitral é factível e satisfatório, com manutenção do ritmo sinusal na maioria dos pacientes (83,8%), após 60 meses de seguimento. O quinto capítulo trata da comparação do potencial evocado auditivo cortical P1 em neonatos e lactentes nascidos a termo e pré-termo. A utilização do potencial evocado auditivo cortical P1 em crianças destaca-se pela verificação da maturação auditiva e pesquisa dos níveis mínimos de respostas corticais. Concluiu-se que o nível mínimo de resposta cortical foi maior para os nascidos pré-termo durante o primeiro mês de vida, e a latência do potencial P1 foi maior para os nascidos pré-termo avaliados até o terceiro mês de vida. Por meio do sexto capítulo, foi estudada a segurança e eficácia de formulações intraoculares contendo Luteína e Zeaxantina, isolada ou combinada com Azul Brilhante ou Azul de Trypan em cirurgia de catarata e vitreorretiniana. O sétimo capítulo trata do diagnóstico precoce da púrpura trombocitopênica trombótica. Diante de seu grave curso e, por muitas vezes estar associada a outros distúrbios hematológicos, o diagnóstico precoce é essencial a fim de melhor definir o prognóstico e a terapêutica adequada. Entre os métodos de diagnóstico laboratorial, a técnica de citometria de fluxo tem mostrado melhor eficácia, devido a sua sensibilidade e especificidade. Pelo presente capítulo foi investigada a presença de ensaios clínicos os quais utilizam a citometria de fluxo como método preferencial para o diagnóstico da PTT a fim de realizar uma reflexão do impacto sobre o desfecho clínico da doença. Por meio do oitavo capítulo é buscada a detecção precoce de neoplasias malignas via biomarcadores tumorais, considerada alternativa promissora, especialmente quando associada a tecnologias inovadoras passíveis de miniaturização. A técnica de Phage Display permite selecionar peptídeos ligantes aos mais diversos alvos, superando a heterogeneidade dos tumores e abrindo caminhos para a evolução das práticas clínicas. Neste capítulo, são abordados os principais aspectos relacionados a tumores e os atuais desafios no diagnóstico da doença, bem como a utilização da técnica de Phage Display na descoberta de novos biomarcadores. Pelo nono capítulo foi realizada a avaliação de biomarcadores em mulheres com dor associada à endometriose. Ambos os tratamentos trouxeram benefícios aos pacientes e a redução dos biomarcadores não foi correlacionada à melhora dos escores de dor pélvica e dismenorreia. Pelo décimo capítulo foram selecionados pacientes submetidos a abdominoplastia e mamoplastia os quais receberam a aplicação de Plasma Rico em Plaquetas (PRP) diretamente na cicatriz e comparando-o com o segmento cicatricial oposto sem PRP. Concluiu-se que o uso intradérmico do PRP, apresentou-se promissor, contribuindo beneficamente na evolução do processo cicatricial, com melhores resultados aos 4 dias e 90 dias de pós-operatório.
10
Marques, Marcia Alessandra Arantes, ed. Avanços Científicos em Medicina 3. Bookerfield Editora, 2022. http://dx.doi.org/10.53268/bkf22040500.
Full textAbstract:
Este livro reúne trabalhos científicos relevantes em Ciências Médicas. Decidiu-se pela divisão em quatro seções: i) área básica; ii) área clínica; iii) medicina diagnóstica; iv) área cirúrgica. Pelo primeiro capítulo são abordados os significativos avanços na qualidade dos conhecimentos acerca da anatomia humana, bem como nas técnicas de preservação dos corpos, nos métodos de estudo e nas formas de intervenção cirúrgicas, permitindo aos profissionais a aquisição de conhecimento, visando a realização de procedimentos cada vez mais seguros, minimamente invasivos e naturalmente, menos danosos aos pacientes, possibilitando assim uma recuperação pós-cirúrgica em menor tempo. Por meio do segundo capítulo são apresentadas algumas das mais recentes tendências da evolução do conhecimento na área da motricidade humana, segundo as diretrizes estabelecidas em 2017 pelo American College of Sports Medicine, que bem demostra a importância atribuída ao exercício físico na saúde. Pelos capítulos terceiro e quarto foi avaliado o tratamento cirúrgico da fibrilação atrial crônica com US em pacientes com lesão valvar mitral, considerando-se caracterização clínica pré-operatória e acompanhamento desses pacientes no pós-operatório imediato, na alta hospitalar e tardio até 60 meses. Concluindo-se que o tratamento cirúrgico da FAC com US concomitante e a cirurgia valvar mitral é factível e satisfatório, com manutenção do ritmo sinusal na maioria dos pacientes (83,8%), após 60 meses de seguimento. O quinto capítulo trata da comparação do potencial evocado auditivo cortical P1 em neonatos e lactentes nascidos a termo e pré-termo. A utilização do potencial evocado auditivo cortical P1 em crianças destaca-se pela verificação da maturação auditiva e pesquisa dos níveis mínimos de respostas corticais. Concluiu-se que o nível mínimo de resposta cortical foi maior para os nascidos pré-termo durante o primeiro mês de vida, e a latência do potencial P1 foi maior para os nascidos pré-termo avaliados até o terceiro mês de vida. Por meio do sexto capítulo, foi estudada a segurança e eficácia de formulações intraoculares contendo Luteína e Zeaxantina, isolada ou combinada com Azul Brilhante ou Azul de Trypan em cirurgia de catarata e vitreorretiniana. O sétimo capítulo trata do diagnóstico precoce da púrpura trombocitopênica trombótica. Diante de seu grave curso e, por muitas vezes estar associada a outros distúrbios hematológicos, o diagnóstico precoce é essencial a fim de melhor definir o prognóstico e a terapêutica adequada. Entre os métodos de diagnóstico laboratorial, a técnica de citometria de fluxo tem mostrado melhor eficácia, devido a sua sensibilidade e especificidade. Pelo presente capítulo foi investigada a presença de ensaios clínicos os quais utilizam a citometria de fluxo como método preferencial para o diagnóstico da PTT a fim de realizar uma reflexão do impacto sobre o desfecho clínico da doença. Por meio do oitavo capítulo é buscada a detecção precoce de neoplasias malignas via biomarcadores tumorais, considerada alternativa promissora, especialmente quando associada a tecnologias inovadoras passíveis de miniaturização. A técnica de Phage Display permite selecionar peptídeos ligantes aos mais diversos alvos, superando a heterogeneidade dos tumores e abrindo caminhos para a evolução das práticas clínicas. Neste capítulo, são abordados os principais aspectos relacionados a tumores e os atuais desafios no diagnóstico da doença, bem como a utilização da técnica de Phage Display na descoberta de novos biomarcadores. Pelo nono capítulo foi realizada a avaliação de biomarcadores em mulheres com dor associada à endometriose. Ambos os tratamentos trouxeram benefícios aos pacientes e a redução dos biomarcadores não foi correlacionada à melhora dos escores de dor pélvica e dismenorreia. Pelo décimo capítulo foram selecionados pacientes submetidos a abdominoplastia e mamoplastia os quais receberam a aplicação de Plasma Rico em Plaquetas (PRP) diretamente na cicatriz e comparando-o com o segmento cicatricial oposto sem PRP. Concluiu-se que o uso intradérmico do PRP, apresentou-se promissor, contribuindo beneficamente na evolução do processo cicatricial, com melhores resultados aos 4 dias e 90 dias de pós-operatório.
Book chapters on the topic "Impact de plaques"
1
Gonçalves, Isabel. "Histologic and Biochemical Composition of Carotid Plaque and Its Impact on Ultrasonographic Appearance." In Multi-Modality Atherosclerosis Imaging and Diagnosis. Springer New York, 2013. http://dx.doi.org/10.1007/978-1-4614-7425-8_16.
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2
Taviani, V., Z. Y. Li, M. Sutcliffe, and J. Gillard. "Impact of Wall Shear Stress and Pressure Variation on the Stability of Atherosclerotic Plaque." In New Trends in Fluid Mechanics Research. Springer Berlin Heidelberg, 2007. http://dx.doi.org/10.1007/978-3-540-75995-9_203.
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3
Yock, Paul G., Peter J. Fitzgerald, Krishnankutty Sudhir, Victor K. Hargrave, and Thomas A. Ports. "Ultrasound Guidance for Catheter-based Plaque Removal and Ablation Techniques: Potential Impact on Restenosis." In Restenosis after Intervention with New Mechanical Devices. Springer Netherlands, 1992. http://dx.doi.org/10.1007/978-94-011-2650-2_6.
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4
Barrak, Fadi. "Insights into Peri-implantitis, Collagen Attachments, Plaque Biofilm Dynamics and the Impact of Biomaterials." In Micro and Nanomanufacturing Volume II. Springer Nature Switzerland, 2024. https://doi.org/10.1007/978-3-031-70499-4_6.
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5
Ozpamuk Karadeniz, Fatma. "Cardiac Macrovascular Complications of Diabetes." In Current Perspective on Diabetes Mellitus in Clinical Sciences. Nobel Tip Kitabevleri, 2023. http://dx.doi.org/10.69860/nobel.9786053359111.9.
Full textAbstract:
Cardiac macrovascular complications are a significant concern in individuals with diabetes mellitus, stemming from the disease’s profound impact on cardiovascular health. Diabetes accelerates the development of atherosclerosis, characterized by the buildup of plaque within arterial walls, which can lead to coronary artery disease (CAD), myocardial infarction (heart attack), and stroke. The underlying mechanisms involve chronic hyperglycemia, which promotes oxidative stress, inflammation, and endothelial dysfunction, contributing to the initiation and progression of vascular damage. Additionally, diabetes often coexists with other cardiovascular risk factors such as hypertension, dyslipidemia, and obesity, further compounding the risk of macrovascular complications. Management strategies focus on aggressive control of blood glucose levels, along with treatment of hypertension and dyslipidemia, to mitigate these risks. Lifestyle modifications, including smoking cessation, adoption of a heart-healthy diet, regular exercise, and adherence to prescribed medications, are crucial in reducing the incidence and severity of cardiac macrovascular complications in individuals with diabetes mellitus.
6
Yuan, Chun, Zach Miller, and Jianming Cai. "Atherosclerosis imaging." In ESC CardioMed, edited by Dudley Pennell. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780198784906.003.0109.
Full textAbstract:
Atherosclerosis imaging goes beyond the simple identification of luminal stenosis. Besides stenosis measurement, there are two main motivations for atherosclerosis imaging: one is to identify the so-called vulnerable plaque, defined as atherosclerotic plaque that poses increased risk of rupture and clinical events, such as heart attack or stroke; the other is to identify ‘positively remodelled’ plaques—plaques that grow outward from the lumen but cause minimal or no stenosis. Cardiovascular magnetic resonance (CMR) has histologically validated capabilities to characterize carotid plaque features in vivo, including a lipid-rich necrotic core, fibrous cap, intraplaque haemorrhage (IPH), calcification, and inflammation. A multicontrast two-dimensional imaging approach has been used in many prospective studies relating baseline CMR characteristics of carotid atherosclerosis with plaque progression and clinical events. These studies have demonstrated the importance of detecting IPH, lipid-rich necrotic cores, and fibrous caps. Building on these findings, a number of three-dimensional CMR techniques have been recently developed that allow higher spatial resolution plaque imaging and easier application clinically with short scan times. Three-dimensional plaque imaging offers flexible imaging plane and view angle analysis, large coverage, multivascular beds capability, and is a fast and cost-effective screening for clinical use. Atherosclerosis imaging has also been applied to detect plaques in other vascular beds such as the coronary artery, intracranial artery, and peripheral artery, although each bed comes with unique imaging needs. Large-scale studies are needed to determine the impact of atherosclerotic plaque CMR on patient outcomes.
7
Cirillo, Milena Solti, Carlos Henrique Barbosa Rozeira, Marcos Fernandes da Silva, et al. "Psychosocial impact of psoriasis: Beyond the skin." In Interconnections of Knowledge: Multidisciplinary Approaches. Seven Editora, 2024. http://dx.doi.org/10.56238/sevened2024.010-001.
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Introduction: Psoriasis is a chronic and recurrent dermatological condition characterized by the appearance of red, slightly raised plaques with silvery scales. These plaques feature a sharp edge that distinguishes the affected area from the surrounding normal skin. It is a chronic dermatological condition that can cause feelings of shame, dirt, and untouchability in sufferers, intensified by the fear of isolation and rejection. The relationship between the nervous and immune systems is intertwined, where emotional stress can affect the skin and dermatological conditions can influence the emotional state of the individual. Objective: To explore the psychosocial impact of psoriasis, analyzing its implications for patients' quality of life and well-being, promoting a better understanding and empathetic approach to those living with the condition. Methodology: The study is classified as basic and theoretical research. The literature review was carried out in the search engines Google Scholar, Scopus and Web of Science, using descriptors such as "psoriasis", "emotional health", "psychological impact" and "quality of life". Discussion and Results: The etiology of psoriasis involves complex interactions between the immune system, environmental factors, and genetic predisposition. Studies indicate that dermatological lesions arise due to the release of inflammatory substances, leading to the formation of erythematous-desquamative lesions. Psoriasis is associated with increased cortisol production in response to chronic stress, negatively impacting overall health. The World Health Organization (WHO) recognizes the psychosocial challenges faced by patients, including social stigma and prejudice. Cognitive behavioral therapy is suggested as an effective tool to help patients manage the condition. Additionally, immunobiologicals represent an innovative therapeutic approach for severe or moderate psoriasis, requiring close monitoring due to potential side effects. Final Considerations: Currently, psoriasis has no definitive cure and can manifest itself unexpectedly, causing discomfort. Treatment may involve medications, injections, topical ointments, and dietary changes. However, for many, the skin condition can persist, leading to frustration. Despite being identified as a dysfunction of the immune system, there are still many uncertainties about this disease.
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Abela, Oliver G., Dilpreet Singh, and George S. Abela. "The resistant atherosclerotic plaques: pathologic features and their impact on revascularization." In Debulking in Cardiovascular Interventions and Revascularization Strategies. Elsevier, 2022. http://dx.doi.org/10.1016/b978-0-12-821451-0.00016-1.
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Mpofana, Nomakhosi, Mokgadi Makgobole, Celenkosini Thembelenkosini Nxumalo, and Pavitra Pillay. "Psoriasis: Clinical Features and Its Impact on Quality of Life." In Psoriasis - Recent Advances in Diagnosis and Treatment [Working Title]. IntechOpen, 2024. http://dx.doi.org/10.5772/intechopen.1005098.
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Psoriasis is a chronic, papulo-squamous, non-infectious, immune-mediated, and inflammatory skin disorder clinically characterized by erythematous sharply demarcated papules and rounded plaques covered by silvery micaceous scales. It is associated with comorbidities such as psoriatic arthritis, depression, obesity, and cardiovascular disease. Psoriasis can also be a source of self and social rejection, thus contributing to stigmatization, alienation, and a decrease in the quality of life (QoL). Due to its complex pathogenesis, a holistic approach is necessary when treating psoriasis. In addition to treating physical symptoms, the patient’s psychological and emotional health should be highly considered to help individuals cope with stigma. Likewise, an increased social awareness of psoriasis may contribute to a better understanding of the disease. Alternative stress management therapies such as spa therapies using dead sea mud and or balneotherapy, yoga, and aromatherapy may be effective in stress management to improve overall well-being and QoL.
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Evans, Denis A., Paul A. Scherr, Nancy R. Cook, et al. "The Impact of Alzheimer’s Disease in the United States Population." In The Oldest Old. Oxford University PressNew York, NY, 1992. http://dx.doi.org/10.1093/oso/9780195050608.003.0013.
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Abstract Awareness of Alzheimer’s disease as a major public health problem has increased strikingly among clinicians, researchers, policy makers and the general public over the past several years. As described by Alzheimer (1907), this term was used only for dementia arising in middle age. Such “presenile” dementia exhibits characteristic neuropathological findings, including neuritic plaques and neurofibrillary tangles. The term “Alzheimer’s disease” is now applied, as well, to the much more common primary degenerative dementia occurring in later life, previously referred to as “senile dementia,” because of apparent clinical and neuropathological (Tomlinson, Blessed, and Roth 1970) similarities regardless of age of onset. Many conditions other than Alzheimer’s disease cause dementia among older persons, including certain strokes, Parkinson’s disease, deficiency of vitamin B12, and a wide range of uncommon conditions. Most population studies, however, suggest that the majority of moderate to severe cognitive impairment in older age groups is due to Alzheimer’s disease, at least by clinical (rather than pathological) criteria for the disease. Regardless of age of onset, Alzheimer’s disease is often devastating for affected individuals and their families. In terms of the total number of persons affected, however, Alzheimer’s disease is predominantly a problem of the oldest old, that is, those aged 85 and older. The occurrence of Alzheimer’s disease is strongly associated with increasing age among those 65 years of age and older. With increasing life expectancy in developed countries, the impact of Alzheimer’s disease will continue to increase.
Conference papers on the topic "Impact de plaques"
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Gijsen, Frank J. H., Jolanda J. Wentzel, Johan C. H. Schuurbiers, Antonius F. W. van der Steen, and Patrick W. Serruys. "Strain Distribution Over Plaques in Human Coronary Arteries Relates to Shear Stress." In ASME 2007 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2007. http://dx.doi.org/10.1115/sbc2007-176313.
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It is well established that atherosclerotic plaques generally develop in low shear stress regions, including curved arterial segments and bifurcations. Once these plaques intrude into the lumen, the shear stress they are exposed to alters with hitherto unknown consequences. We hypothesize that in the more advanced stages of the disease, shear stress has an important impact on plaque composition in such a way that high shear stress enhances plaque vulnerability through its biological impact on the endothelium. We investigated this hypothesis by studying the relationship between shear stress and strain, a marker for plaque composition, in human coronary arteries.
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Gijsen, Frank, Jolanda Wentzel, Johan Schuurbiers, et al. "Shear Stress Modulates Plaque Composition in Human Coronary Arteries In Vivo." In ASME 2008 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2008. http://dx.doi.org/10.1115/sbc2008-192764.
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It is well established that atherosclerotic plaques generally develop in low shear stress regions, including curved arterial segments and bifurcations1. Once these plaques intrude into the lumen, the shear stress they are exposed to alters with hitherto unknown consequences. We hypothesize that in the more advanced stages of the disease, shear stress has an important impact on plaque composition in such a way that high shear stress enhances plaque vulnerability through its biological impact on the endothelium2. We investigated this hypothesis previously by studying the relationship between shear stress and strain, a marker for plaque composition, in human coronary arteries3. In this study, we will extend that study by investigating how shear stress influences changes of strain, and thus plaque composition, over a period of 6 months.
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Kauffmann, Keith, and Daryl Hertema. "Dynamic Modeling and Correlation to Impact Testing of Welded Ribbed Plaques." In International Congress & Exposition. SAE International, 1995. http://dx.doi.org/10.4271/950641.
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Gijsen, Frank, Hans Schuurbiers, Michiel Schaap, Anton van der Steen, and Jolanda Wentzel. "A New 3D Reconstruction Method for Human Coronary Bifurcations for Shear Stress Computations." In ASME 2012 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/sbc2012-80251.
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Atherosclerosis is characterized by lipid accumulation in the arterial wall, followed by an inflammatory response. Plaque formation is generally observed near bifurcations in coronary arteries. The composition of atherosclerotic plaques depends on the location, and it was hypothesized that blood flow induced shear stress influences plaque composition2. To study the impact of shear stress on atherosclerotic disease in human coronary arteries, we developed a technique that enables us to generate 3D lumen reconstruction based on multislice computer tomography (MSCT) and intravascular ultrasound (IVUS).We describe two approaches to generate 3D reconstructions of human coronary artery bifurcations and apply them to coronary segments with bifurcations. We will evaluate the effect on shear stress distribution and its relationship to wall thickness.
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Motuku, M., U. K. Vaidya, G. M. Janowski, G. Basappa, and S. Jeelani. "Effect of Impact Velocity and Impactor Mass on the Low Velocity Impact Response of Liquid Molding Vinyl Ester-350 Resin and Fiber-Reinforced Plaques." In ASME 2000 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2000. http://dx.doi.org/10.1115/imece2000-1229.
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Abstract The influence of test conditions on the low velocity impact (LVI) response and damage evolution in neat resin plaques was investigated and documented. Specifically, the effect of impactor mass, velocity, and corresponding impact energy on the LVI response and damage evolution in unreinforced DERAKANE vinyl ester 411-350-resin system was studied. An instrumented drop weigh test machine was used to conduct the low velocity impact tests. The room temperature response of the material to impact loading and damage evolution was investigated using the impact load histories, impact plots and fractography analysis. This study is built upon previous work by the authors on LVI of neat resin systems, particularly those that have emerged as a new class of resins in liquid molding process. The study was motivated by the need for data and understanding of the failure characteristics of the individual constituents of a composite material such as in modeling of damage propagation and failure criteria analysis. For constant impact velocity, the time-to-maximum load (tm), total impact duration (tt), and the energy-to-maximum load to total energy absorbed (Em/Et) ratio increased, and energy absorbed after peak load (Ep) decreased with the mass of the impactor. For constant impactor mass, the time-to-maximum load and total impact duration decreased, the Em/Et ratio remained fairly the same, and energy absorbed after peak load increased with velocity; i.e., the impact velocity and mass had opposing effects on the time-to-maximum load, the total impact duration, Em/Et and energy absorbed after peak load. A single layer of plain-weave S2-glass fabric was incorporated in some of the unreinforced plaques in order to analyze the influence of reinforcement on the impact response and damage evolution. Insertion of a fabric layer aided in containment of the damage within the bounds of the specimen and to isolate the failure characteristics, which enabled further analysis of the impact response and damage evolution.
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Suraci, S. V., C. Spinazzola, and D. Fabiani. "Analysis on the impact of additives on space charge behavior of thermally aged XLPE plaques." In 2022 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP). IEEE, 2022. http://dx.doi.org/10.1109/ceidp55452.2022.9985288.
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Nase, Gabriele, P. Johannes Helm, Tomohiro Oguchi, et al. "Local impact of perivascular plaques on cerebral blood flow dynamics in a transgenic mouse model of Alzheimer's disease." In Biomedical Optics (BiOS) 2008, edited by Ammasi Periasamy and Peter T. C. So. SPIE, 2008. http://dx.doi.org/10.1117/12.762739.
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Anderson, David, Sarah Briggs, Anne Mckay, Susan Mccluskey, Angela Wright, and George Chalmers. "Survival on antifibrotic therapy in IPF – the impact of pleural plaques, concomitant emphysema and definite vs possible UIP." In ERS International Congress 2019 abstracts. European Respiratory Society, 2019. http://dx.doi.org/10.1183/13993003.congress-2019.pa1340.
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Timmins, Lucas H., Jonathan D. Suever, Parham Eshtehardi, et al. "Correlation of Longitudinal Intravascular Ultrasound Data for the Clinical Assessment of Coronary Artery Disease Progression." In ASME 2012 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/sbc2012-80630.
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Virtual histology-intravascular ultrasound (VH-IVUS) has gained increasing utility in the cardiac catheterization laboratory, not only in determining underlying atherosclerotic lesion composition prior to stent placement, but also in clinical studies assessing the natural history of coronary artery disease (CAD) [1]. Furthermore, VH-IVUS has provided an excellent means of quantifying disease progression by comparing data sets collected over time (i.e., longitudinal studies) and potentially identifying rapidly progressing and potentially vulnerable plaques. One difficulty, however, in analyzing VH-IVUS derived CAD progression is the accurate co-registration of image sets collected over a period of time. Commonly, an expert VH-IVUS image reader reviews these image sets side-by-side on a display and co-registers images along the vessel main axis, herein axially co-registered, by identifying image locations relative to fiduciary anatomical markers (e.g., branches). Despite this method being the standard for analyzing CAD progression, it is limited by the inability to accurately co-register VH-IVUS data in the circumferential direction (i.e., rotating images such that their cylindrical coordinate bases coincide; herein circumferentially co-registered). Thus, a significant amount of information on focal plaque progression is lost that could provide a greater understanding of the natural evolution of CAD, the effects of various pharmaceutical agents (e.g., statins) on lesion composition changes, and the impact of local mechanical factors that induce plaque progression/regression and transformation.
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Tasios, Stergios, Evangelos Chytis, and Stefanos Gousias. "Accountants’ perceptions of tax amnesty: A survey during the COVID-19 pandemic in Greece." In Corporate governance: A search for emerging trends in the pandemic times. Virtus Interpress, 2021. http://dx.doi.org/10.22495/cgsetpt3.
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Although humanity has faced many plaques and epidemics from antiquity, the COVID-19 came as a tidal wave, overwhelming nations and governments. Restrictive measures, social distancing and ultimately lockdown and quarantine, emerged as a response to decelerate the spread of the disease and save human lives. These measures may have decreased COVID-19 cases, they had, however, an adverse impact on economic activity and stock markets (Ashraf, 2020). Research shows that the pandemic has already influenced the United States (the US), Germany, and Italy‘s stock markets more than the global financial crises (Shehzad, Xiaoxing, & Kazouz 2020)
Reports on the topic "Impact de plaques"
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Gao, Meihong, Chengchun Zhan, Tianyu Du, et al. The Impact of the Plaques on the Pulsating Flow Characteristics in the Stenotic Femoral Artery. "Prof. Marin Drinov" Publishing House of Bulgarian Academy of Sciences, 2021. http://dx.doi.org/10.7546/crabs.2021.07.16.
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Tsiogka, Aikaterini, Stamatios Gregoriou, Alexander Stratigos, et al. The impact of treatment with IL-17/IL-23 inhibitors on subclinical atherosclerosis in patients with plaque psoriasis and/or psoriatic arthritis: a systematic review. INPLASY - International Platform of Registered Systematic Review and Meta-analysis Protocols, 2022. http://dx.doi.org/10.37766/inplasy2022.12.0102.
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