4,826 research outputs found

    Well-posedness of the Ericksen-Leslie system

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    In this paper, we prove the local well-posedness of the Ericksen-Leslie system, and the global well-posednss for small initial data under the physical constrain condition on the Leslie coefficients, which ensures that the energy of the system is dissipated. Instead of the Ginzburg-Landau approximation, we construct an approximate system with the dissipated energy based on a new formulation of the system.Comment: 16 page

    Different gene expression modulation is the major effect fue to shear stress and stent application in huvecs model: preliminary results

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    Although it is known that disturbed shear stress may cause endothelial damage, the mechanism by which a stent procedure may affect the endothelium is not yet fully clarify. We present the preliminary data on gene expression analysis of human endothelial cells in a laminar flow bioreactor (LFB) system submitted to different physical (flow changes) and/or mechanical (stent application) stimuli. Our preliminary results show that low shear stress together with stent procedure are the experimental conditions that mainly modulate the highest number of genes in human endothelial model. Those genes belong to pathways specifically involved in the endothelial dysfunctio

    Detector setup for Heavy Ion Computed Tomography

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    Thermodynamical Consistent Modeling and Analysis of Nematic Liquid Crystal Flows

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    The general Ericksen-Leslie system for the flow of nematic liquid crystals is reconsidered in the non-isothermal case aiming for thermodynamically consistent models. The non-isothermal model is then investigated analytically. A fairly complete dynamic theory is developed by analyzing these systems as quasilinear parabolic evolution equations in an LpLqL^p-L^q-setting. First, the existence of a unique, local strong solution is proved. It is then shown that this solution extends to a global strong solution provided the initial data are close to an equilibrium or the solution is eventually bounded in the natural norm of the underlying state space. In these cases, the solution converges exponentially to an equilibrium in the natural state manifold

    Genetic Variants of the Renin-Angiotensin-Aldosterone System and Reverse Remodeling After Cardiac Resynchronization Therapy

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    Background: Reverse remodeling (RR) after cardiac resynchronization therapy (CRT) is associated with favorable clinical outcomes in heart failure (HF). The renin-angiotensin-aldosterone system (RAAS) is involved in the remodeling process. Methods and Results: We assessed the association between RR and 8 common RAAS gene variants, which were determined by TaqMan assays, in 156 outpatients with chronic HF. RR was defined as a O15% decrease in left ventricular end systolic volume (LVESV) at 9 (interquartile range 7e12) months after CRT. We matched 76 patients who did not show RR (RR) to 80 RR? control subjects by age, sex, HF etiology, New York Heart Association (NYHA) functional class and left ventricular ejection fraction (LVEF). The frequency of the minor allele of the NR3C2 gene (rs5522 C/T), encoding the mineralocorticoid receptor, was higher in RR than in RR (24/126 vs 10/150; P value after false discovery rate correction: <.0193). Conversely, LVESV decreased significantly less after CRT in carriers of the NR3C2 minor C allele (P 5 .02). After adjustment for age, sex, NYHA functional class, previous myocardial infarction, atrial fibrillation, and LVEF, RR remained independently associated with NR3C2 C allele carriage (odds ratio 3.093, 95% confidence interval 1.253e7.632). Conclusions: The association of RR after CRT with a common polymorphism in the mineralocorticoid receptor gene involved in aldosterone signaling suggests a possible role for variants in RAAS genes in progressive LV function decline, despite apparently effective CRT

    Severity of oxidative stress and inflammatory activation in end-stage heart failure patients are unaltered after 1 month of left ventricular mechanical assistance

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    This study investigates the impact of early left ventricular (LV)-mechanical unloading on systemic oxidative stress and inflammation in terminal heart failure patients and their impact both on multi organ failure and on intensive care unit (ICU) stay. Circulating levels of urinary 15-isoprostane-F2t (8-epi-PGF2a) and pro-inflammatory markers [plasma interleukin (IL)-6, IL-8, and urinary neopterin, a monocyte activation index] were analyzed in 20 healthy subjects, 22 stable end-stage heart failure (ESHF) patients and in 23 LV assist device (LVAD) recipients at pre-implant and during first post-LVAD (PL) month. Multiorgan function was evaluated by total Sequential Organ Failure Assessment (tSOFA) score. In LVAD recipients the levels of oxidative-inflammatory markers and tSOFA score were higher compared to other groups. After device implantation 8-epi-PGF2a levels were unchanged, while IL-6, and IL-8 levels increased during first week, and at 1 month returned to pre-implant values, while neopterin levels increased progressively during LVAD support. The tSOFA score worsened at 1 PL-week with respect to pre-implant value, but improved at 1 PL-month. The tSOFA score related with IL-6 and IL-8 levels, while length of ICU stay related with pre-implant IL-6 levels. These data suggest that hemodynamic instability in terminal HF is associated to worsening of systemic inflammatory and oxidative milieu that do not improve in the early phase of hemodynamic recovery and LV-unloading by LVAD, affecting multi-organ function and length of ICU stay. This data stimulate to evaluate the impact of inflammatory signals on long-term outcome of mechanical circulatory support

    Elective Open Suprarenal Aneurysm Repair in England from 2000 to 2010 an Observational Study of Hospital Episode Statistics

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    Background: Open surgery is widely used as a benchmark for the results of fenestrated endovascular repair of complex abdominal aortic aneurysms (AAA). However, the existing evidence stems from single-centre experiences, and may not be reproducible in wider practice. National outcomes provide valuable information regarding the safety of suprarenal aneurysm repair. Methods: Demographic and clinical data were extracted from English Hospital Episodes Statistics for patients undergoing elective suprarenal aneurysm repair from 1 April 2000 to 31 March 2010. Thirty-day mortality and five-year survival were analysed by logistic regression and Cox proportional hazards modeling. Results: 793 patients underwent surgery with 14% overall 30-day mortality, which did not improve over the study period. Independent predictors of 30-day mortality included age, renal disease and previous myocardial infarction. 5-year survival was independently reduced by age, renal disease, liver disease, chronic pulmonary disease, and known metastatic solid tumour. There was significant regional variation in both 30-day mortality and 5-year survival after risk-adjustment. Regional differences in outcome were eliminated in a sensitivity analysis for perioperative outcome, conducted by restricting analysis to survivors of the first 30 days after surgery. Conclusions: Elective suprarenal aneurysm repair was associated with considerable mortality and significant regional variation across England. These data provide a benchmark to assess the efficacy of complex endovascular repair of supra-renal aneurysms, though cautious interpretation is required due to the lack of information regarding aneurysm morphology. More detailed study is required, ideally through the mandatory submission of data to a national registry of suprarenal aneurysm repair

    On the General Ericksen-Leslie System: Parodi's Relation, Well-posedness and Stability

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    In this paper we investigate the role of Parodi's relation in the well-posedness and stability of the general Ericksen-Leslie system modeling nematic liquid crystal flows. First, we give a formal physical derivation of the Ericksen-Leslie system through an appropriate energy variational approach under Parodi's relation, in which we can distinguish the conservative/dissipative parts of the induced elastic stress. Next, we prove global well-posedness and long-time behavior of the Ericksen-Leslie system under the assumption that the viscosity μ4\mu_4 is sufficiently large. Finally, under Parodi's relation, we show the global well-posedness and Lyapunov stability for the Ericksen-Leslie system near local energy minimizers. The connection between Parodi's relation and linear stability of the Ericksen-Leslie system is also discussed

    Anesthesia of Epinephelus marginatus with essential oil of Aloysia polystachya: an approach on blood parameters

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    This study investigated the anesthetic potential of the essential oil (EO) of Aloysia polystachya in juveniles of dusky grouper (Epinephelus marginatus). Fish were exposed to different concentrations of EO of A. polystachya to evaluate time of induction and recovery from anesthesia. In the second experiment, fish were divided into four groups: control, ethanol and 50 or 300 mu L L-1 EO of A. polystachya, and each group was submitted to induction for 3.5 min and recovery for 5 or 10 min. The blood gases and glucose levels showed alterations as a function of the recovery times, but Na+ and K+ levels did not show any alteration. In conclusion, the EO from leaves of A. polystachya is an effective anesthetic for dusky grouper, because anesthesia was reached within the recommended time at EO concentrations of 300 and 400 mu L L-1. However, most evaluated blood parameters showed compensatory responses due to EO exposure.Fundacao de Amparo a Pesquisa do Estado do Rio Grande do Sul/Programa de Apoio a Nucleos de Excelencia (FAPERGS/PRONEX) [10/0016-8]; Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq) [470964/2009-0]; Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior, Brazil (CAPES)info:eu-repo/semantics/publishedVersio
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