Search results for "Dynamics"

Dynamic 4D Blood Flow Representation in the Aorta and Analysis from Cine-MRI in Patients

2007

International audience; Abstract: Natural evolution of aortic disease is characterized by a diameter increase that can result in aortic dissection or rupture. Currently the evaluation of risk of rupture or dissection is based on the size of the aorta. However, this parameter is not always relevant and it appears necessary to define new parameters. In this perspective, 3D velocity imaging acquired with ECG gated velocity-encoded cine-MRI allows the aortic blood flow study. As the acquired images are not directly usable, the present study proposes a 4D-representation Of aortic blood flow in order to optimize the visualization of the particularities of non-laminar flow within the aorta. Image …

Role of Hemodynamic Forces in Unruptured Intracranial Aneurysms: An Overview of a Complex Scenario.

2017

Background An understanding of the natural history of unruptured intracranial aneurysms (IAs) has always played a critical role in presurgical or endovascular planning, to avoid possibly fatal events. Size, shape, morphology, and location are known risk factors for rupture of an aneurysm, but morphologic parameters alone may not be sufficient to perform proper rupture risk stratification. Methods We performed a systematic PubMed search and focused on hemodynamics forces that may influence aneurysmal initiation, growth, and rupture. Results We included 223 studies describing several hemodynamic parameters related to aneurysm natural history. In these studies, different modalities of aneurysm…

Visual tasks and stance width influence the spatial magnitude and temporal dynamics of standing body sway in 6- to 12-year old children.

2017

Dynamic tuning of the director field in liquid crystal shells using block copolymers

2020

When an orientationally ordered system, like a nematic liquid crystal (LC), is confined on a self-closing spherical shell, topological constraints arise with intriguing consequences that depend critically on how the LC is aligned in the shell. We demonstrate reversible dynamic tuning of the alignment, and thereby the topology, of nematic LC shells stabilized by the nonionic amphiphilic block copolymer Pluronic F127. Deep in the nematic phase, the director (the average molecule orientation) is tangential to the interface, but upon approaching the temperature TNI of the nematic– isotropic transition, the director realigns to normal. We link this to a delicate interplay between an interfacial …

Motor asymmetry attenuation in older adults during imagined arm movements

2014

International audience; Laterality is an important feature of motor behavior. Several studies have shown that lateralization in right-handed young adults (i.e., right versus left arm superiority) emerges also during imagined actions, that is when an action is internally simulated without any motor output. Such information, however, is lacking for elderly people and it could be valuable to further comprehend the evolution of mental states of action in normal aging. Here, we evaluated the influence of age on motor laterality during mental actions. Twenty-four young (mean age: 24.7 +/- 4.4 years) and 24 elderly (mean age: 72.4 +/- 3.6 years) participants mentally simulated and actually execute…

Noninvasive assessment of baroreflex sensitivity in post-MI patients by an open loop parametric model of RR-systolic pressure interactions

2003

Noninvasive evaluation of baroreflex sensitivity is considered an important goal for diagnosis and prognosis in post-MI patients. Methodological approach and physiological measure conditions may be the main causes for the differences found with respect to the standard Phenylephrine test. In this study, three linear parametric models, describing variability and mutual interactions of RR interval and systolic arterial pressure (SAP), were compared in relation to their ability to quantify baroreflex gain, using the Phenylephrine test index (Phe/sub BRS/) as reference. By monovariate autoregressive (AR) model, bivariate AR model and open loop ARXAR model, specific gain indexes (/spl alpha//sub …

Fast Isolation by AFLP of Sequences Containing Repeats

2013

Fast isolation by AFLP of sequences containing repeats (FIASCO) is a rapid and simple method for separating microsatellite-containing DNA fragments from genomic DNA de novo. The method takes the advantage of the amplified fragment length polymorphism (AFLP) technique that relies on effective digestion-ligation reaction. The repeat-containing fragments are selectively hybridized to biotinylated probes and harvested by streptavidin-coated magnetic beads. The enriched microsatellite-containing fragments can be cloned and sequenced to yield a variety of microsatellite loci for applications in many different fields in molecular genetics.

[Compensation mechanisms of perioperative anemia].

2002

Neprilysin inhibition, endorphin dynamics, and early symptomatic improvement in heart failure: a pilot study

2020

Altres ajuts: This work was supported in part by Fundació La Marató de TV3 (201516-10, 201502-30), Societat Catalana de Cardiologia, "la Caixa" Banking Foundation. Altres ajuts: PERIS/SLT002-16-00234 Sacubitril/valsartan is a first-in-class angiotensin receptor-neprilysin inhibitor developed for the treatment of heart failure with reduced ejection fraction. Its benefits are achieved through the inhibition of neprilysin (NEP) and the specific blockade of the angiotensin receptor AT1. The many peptides metabolized by NEP suggest multifaceted potential consequences of its inhibition. We sought to evaluate the short-term changes in serum endorphin (EP) values and their relation with patients' p…

Coarctation of the Aorta: Quantitative Analysis by Transesophageal Echocardiography

1987

Summary Transesophageal echocardiography and standard two-dimensional echocardiography were performed in 15 patients with suspected coarctation of the aorta. Aortic diameters and crosssectional areas were determined by means of TEE and compared with clinical findings and catheterization data. The isthmus of the aorta could be imaged in all patients using TEE, but in only seven patients using standard suprasternal echocardiography. Compared with controls, aortic diameters were narrowed in 9 of 15 patients, and cross-sectional areas were reduced in 13 of 15. There was a satisfactory correlation between TEE data and angiographic and hemodynamic data. TEE is a promising method of a diagnosing a…