Mechanical identification of layer-specific properties of mouse carotid arteries using 3D-DIC and a hyperelastic anisotropic constitutive model

The role of mechanics is known to be of primary order in many arterial diseases; however, determining mechanical properties of arteries remains a challenge. This paper discusses the identifiability of the passive mechanical properties of a mouse carotid artery, taking into account the orientation of collagen fibres in the medial and adventitial layers. On the basis of 3D digital image correlation measurements of the surface strain during an inflation/extension test, an inverse identification method is set up. It involves a 3D finite element mechanical model of the mechanical test and an optimisation algorithm. A two-layer constitutive model derived from the Holzapfel model is used, with five and then seven parameters. The five-parameter model is successfully identified providing layer-specific fibre angles. The seven-parameter model is over parameterised, yet it is shown that additional data from a simple tension test make the identification of refined layer-specific data reliable.Comment: PB-CMBBE-15.pd

Reduction of the model noise in non-linear reconstruction via an efficient calculation of the incident field: application to a 434 MHz Scanner

Microwave tomography has been drastically boosted by the development of efficient reconstruction algorithms based on an iterative solution of the corresponding non-linear inverse problem. The accuracy of the electric field radiated by the antennas of a microwave scanner, inside the target area, has been shown to play a significant role on the overall image quality. Taking into account the antenna environment is of prime importance, especially when operating at low frequency. For instance, the wall of a 60 cm diameter whole-body microwave scanner cannot be neglected at 434 MHz, even when using the immersion technique consisting of putting the target in water. Indeed, at such a frequency, the attenuation introduced by water is not sufficient to avoid multiple reflections on the scanner boundary walls. Consequently, the method of calculating the incident field constitutes a key factor in iteratively solving non-linear inverse problems. The selected technique must accommodate high accuracy while maintaining acceptable calculation complexity. In this paper, three distinct techniques are analysed. They are based on the use of i) free-space and ii) non free-space Green's function, and iii) a FDTD approach. All these techniques have been firstly investigated for their 2D version, being used in 2D reconstruction algorithms. However, the scattered field data are collected in a 3D scanner. For assessing the validity of the previous 2D techniques, their results have been compared to both experimentally and 3D-FDTD results.Peer ReviewedPostprint (published version

Temporal dynamics of Chaoborus larvae (Diptera : Chaoboridae) in the tropical ecosystem (lake Ayamé I ; Côte d’Ivoire).

Chaoborus larvae are voracious predators of zooplankton able to change their specific composition and size structure. Thus they appear as competitors of fish. They also represent food for planktophage fish. The temporal dynamics of Chaoborus larvae was studied (from january to october 1997) in the fishery of Bakro (5°33’N and 3°15’W) situated in lake Ayamé I (Côte d’Ivoire). Two peaks of density were observed : the most pronouced in March (end of the major dry season) with 747 ind./m2, and another, less pronouced in June (end of the major rainy season), with 280 ind./m2. Differences between densities may well be explained by the advent of the rainy season which leads to a decline in trophic resources (zooplankton) and exposes Chaoborus larvae to predation by fish.Key-words : Chaoborus larvae, Dynamics, lake Ayamé I, Côte d’Ivoire,West Africa

Imaging the posterior mediastinum: A multimodality approach

The posterior mediastinum contains several structures that can produce a wide variety of pathologic conditions. Descending thoracic aorta, esophagus, azygos and hemiazygos veins, thoracic duct, lymph nodes, adipose tissue, and nerves are all located in this anatomical region and can produce diverse abnormalities. Although chest radiography may detect many of these pathologic conditions, computed tomography and magnetic resonance are the imaging modalities of choice for further defining the relationship of posterior mediastinal lesions to neighboring structures and showing specific imaging features that narrow the differential diagnosis. This review emphasizes modality-related answers to morphologic questions, which provide precise diagnostic information

Microwave imaging techniques for biomedical applications

Microwaves have been considered for medical applications involving the detection of organ movements and changes in tissue water content. More particularly cardiopulmonary interrogation via microwaves has resulted in various sensors monitoring ventricular volume change or movement, arterial wall motion, respiratory movements, pulmonary oedema, etc. In all these applications, microwave sensors perform local measurements and need to be displaced for obtaining an image reproducing the spatial variations of a given quantity. Recently, advances in the area of inverse scattering theory and microwave technology have made possible the development of microwave imaging and tomographic instruments. This paper provides a review of such equipment developed at Suplec and UPC Barcelona, within the frame of successive French-Spanish PICASSO cooperation programs. It reports the most significant results and gives some perspectives for future developments. Firstly, a brief historical survey is given. Then, both technological and numerical aspects are considered. The results of preliminary pre-clinical assessments and in-lab experiments allow to illustrate the capabilities of the existing equipment, as well as its difficulty in dealing with clinical situations. Finally, some remarks on the expected development of microwave imaging techniques for biomedical applications are given.Peer ReviewedPostprint (published version

Key Figures on the Alt Empordà 2020

Demografia; Salut; Economia; TerritoriDemografía; Salud; Economía; TerritorioDemographics; Health; Economy; TerritoryL’objectiu d’aquest document és proporcionar un conjunt de visualitzacions intuïtives, clares i concises sobre alguns dels indicadors disponibles de l’Alt Empordà amb la intenció d’aportar una mirada estratègica de l’estat actual de la comarca.El objetivo de este documento es proporcionar un conjunto de visualizaciones intuitivas, claras y concisas sobre algunos de los indicadores disponibles del Alt Empordà con la intención de aportar una visión estratégica del estado actual de la comarca.The objective of this document is to provide a series of intuitive, clear and concise visualisations of some of the available figures on the Alt Empordà to provide a strategic view of the current state of the region

Key Figures on the Alt Empordà 2021

Demografia; Salut; Economia; TerritoriDemografía; Salud; Economía; TerritorioDemographics; Health; Economy; TerritoryIndicadores Clave del Alt Empordà 2021 presenta una selección de datos estadísticos sobre el Alt Empordà y la demarcación de Girona. Estos datos se enmarcan en el ámbito municipal en todos aquellos casos en que ha sido posible pero en muchos otros no se ha podido obtener información detallada, por lo que las cifras son de ámbito comarcal o provincial. Este documento quiere aportar una visión general que facilite conocer el estado del territorio en el momento de la publicación: las tendencias recientes, incluyendo datos demográficos, sociodemográficos, de salud, economía, territorio y sus recursos.Key Figures on the Alt Empordà 2021 presents a selection of statistics on the Alt Empordà and the area of Girona. Whenever possible, these data are defined within the municipal scope, but in many cases it has not been possible to obtain sufficiently detailed information, so the figures are regional or provincial. This document aims to provide a general view to help know the state of the area at the time of publication: recent trends, including data on demographics, socio-demographics, health, economy, the territory and its resources

Imaging of Pulmonary Infection

The spectrum of organisms known to cause respiratory infections is broad and constantly increasing as new pathogens are identified, and an increasing number of patients have impaired immunity due to disease or medications. The radiographic manifestations of a given organism may be variable depending on the immunologic status of the patient and the presence of pre- or coexisting lung disease. Moreover, the clinical data and radiographic findings often fail to lead to a definitive diagnosis of pneumonia because there are an extensive number of noninfectious processes associated with febrile pneumonitis. This chapter describes and illustrates the characteristic imaging manifestations of the most common community- acquired pneumonias, nosocomial pneumonias, and the various infections seen in both immunocompetent and immunocompromised patients