711 research outputs found

    Nasal fibrosis: long-term follow up of four cases of eosinophilic angiocentric fibrosis

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    Eosinophilic angiocentric fibrosis is a rare, benign cause of submucosal thickening and fibrosis within the upper respiratory tract. It predominantly affects the nose although cases have been reported in the subglottis. We describe four cases of the disease centred around the nasal cavity, with widespread infiltration of the facial soft tissues and orbit in three of the four patients. Each underwent long term follow up. Multiple surgical resections were required with two of our patients and, to date, medical therapy has been of limited help. The disease process, with its clinical and characteristic histopathological findings, is described. We also discuss the management of the disease following a comprehensive review of, and comparison with, the few prior reported cases

    Psychological profile of laryngectomized patients

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    Larynx cancer is one of the most susceptible form of cancer susceptible to induce alteration of the patient’s psychological profile due to the social role that the larynx has in communication. Oral communication is severely impaired even after voice rehabilitation of the laryngectomized patients, so that the social rehabilitation is somewhat not only a medical but also a social problem. The psychological profile of these patients is altered in a way that dealing with the disease is sometimes neglected and the interaction with the outside world in terms of oral communication is totally abandoned. The starting point for depression in these cases is the acknowledgement of the disease and is, in some cases, the entire medical environment. Facial scarring, the inability to verbally interact with other human, as well as the presence of the tracheostoma, are all deciding factors in the presence of a low self-esteem for these particular patients. Psychological counseling is a mandatory approach for laryngectomized patients, in order to improve their ability to cope with cancer and providing better recovery chances

    Influence of coating on the thermal resistance of a Ni-Based superalloy

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    In this paper, the influence of M-CrAlY polycrystalline coating on the thermal fatigue behavior of a Nickel-base superalloy has been investigated. A special device using a rotating bending machine and two thermal sources has been used to perform thermo-mechanical tests. The two thermal sources have been set to obtain temperature variations between 750 and 1120 °C in the central part of the specimens, with a frequency of 0.1 Hz. The results showed a deleterious effect of the coating on the fatigue resistance. Numerical simulations have been carried out on SAMCEF to determine the thermo-mechanical field of the so-tested specimens. Calculated thermo-mechanical cycles of critical sites are associated with microstructure evolution and damage by cracking observed on the specimens. Damage mechanisms related to the presence of coating are discussed

    Parameter Inference in the Pulmonary Circulation of Mice

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    This study focuses on parameter inference in a pulmonary blood cir- culation model for mice. It utilises a fluid dynamics network model that takes selected parameter values and aims to mimic features of the pulmonary haemody- namics under normal physiological and pathological conditions. This is of medical relevance as it allows monitoring of the progression of pulmonary hypertension. Constraint nonlinear optimization is successfully used to learn the parameter values

    Simplified and yet Turing universal spiking neural P systems with communication on request

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    The file attached to this record is the author's final peer reviewed version.Spiking neural P systems are a class of third generation neural networks belonging to the framework of membrane computing. Spiking neural P systems with communication on request (SNQ P systems) are a type of spiking neural P system where the spikes are requested from neighbouring neurons. SNQ P systems have previously been proved to be universal (computationally equivalent to Turing machines) when two types of spikes are considered. This paper studies a simpli ed version of SNQ P systems, i.e. SNQ P systems with one type of spike. It is proved that one type of spike is enough to guarantee the Turing universality of SNQ P systems. Theoretical results are shown in the cases of the SNQ P system used in both generating and accepting modes. Furthermore, the influence of the number of unbounded neurons (the number of spikes in a neuron is not bounded) on the computation power of SNQ P systems with one type of spike is investigated. It is found that SNQ P systems functioning as number generating devices with one type of spike and four unbounded neurons are Turing universal

    Left Ventricular Trabeculations Decrease the Wall Shear Stress and Increase the Intra-Ventricular Pressure Drop in CFD Simulations

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    The aim of the present study is to characterize the hemodynamics of left ventricular (LV) geometries to examine the impact of trabeculae and papillary muscles (PMs) on blood flow using high performance computing (HPC). Five pairs of detailed and smoothed LV endocardium models were reconstructed from high-resolution magnetic resonance images (MRI) of ex-vivo human hearts. The detailed model of one LV pair is characterized only by the PMs and few big trabeculae, to represent state of art level of endocardial detail. The other four detailed models obtained include instead endocardial structures measuring ≥1 mm2 in cross-sectional area. The geometrical characterizations were done using computational fluid dynamics (CFD) simulations with rigid walls and both constant and transient flow inputs on the detailed and smoothed models for comparison. These simulations do not represent a clinical or physiological scenario, but a characterization of the interaction of endocardial structures with blood flow. Steady flow simulations were employed to quantify the pressure drop between the inlet and the outlet of the LVs and the wall shear stress (WSS). Coherent structures were analyzed using the Q-criterion for both constant and transient flow inputs. Our results show that trabeculae and PMs increase the intra-ventricular pressure drop, reduce the WSS and disrupt the dominant single vortex, usually present in the smoothed-endocardium models, generating secondary small vortices. Given that obtaining high resolution anatomical detail is challenging in-vivo, we propose that the effect of trabeculations can be incorporated into smoothed ventricular geometries by adding a porous layer along the LV endocardial wall. Results show that a porous layer of a thickness of 1.2·10−2 m with a porosity of 20 kg/m2 on the smoothed-endocardium ventricle models approximates the pressure drops, vorticities and WSS observed in the detailed models.This paper has been partially funded by CompBioMed project, under H2020-EU.1.4.1.3 European Union’s Horizon 2020 research and innovation programme, grant agreement n◦ 675451. FS is supported by a grant from Severo Ochoa (n◦ SEV-2015-0493-16-4), Spain. CB is supported by a grant from the Fundació LaMarató de TV3 (n◦ 20154031), Spain. TI and PI are supported by the Institute of Engineering in Medicine, USA, and the Lillehei Heart Institute, USA.Peer ReviewedPostprint (published version

    Hybridization and speciation in angiosperms: a role for pollinator shifts?

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    The majority of convincingly documented cases of hybridization in angiosperms has involved genetic introgression between the parental species or formation of a hybrid species with increased ploidy; however, homoploid (diploid) hybridization may be just as common. Recent studies, including one in BMC Evolutionary Biology, show that pollinator shifts can play a role in both mechanisms of hybrid speciation
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