Prediction of guidewire-induced aortic deformations during EVAR: a finite element and in vitro study

Introduction and aims: During an Endovascular Aneurysm Repair (EVAR) procedure a stiff guidewire is inserted from the iliac arteries. This induces significant deformations on the vasculature, thus, affecting the pre-operative planning, and the accuracy of image fusion. The aim of the present work is to predict the guidewire induced deformations using a finite element approach validated through experiments with patient-specific additive manufactured models. The numerical approach herein developed could improve the pre-operative planning and the intra-operative navigation. Material and methods: The physical models used for the experiments in the hybrid operating room, were manufactured from the segmentations of pre-operative Computed Tomography (CT) angiographies. The finite element analyses (FEA) were performed with LS-DYNA Explicit. The material properties used in finite element analyses were obtained by uniaxial tensile tests. The experimental deformed configurations of the aorta were compared to those obtained from FEA. Three models, obtained from Computed Tomography acquisitions, were investigated in the present work: A) without intraluminal thrombus (ILT), B) with ILT, C) with ILT and calcifications. Results and discussion: A good agreement was found between the experimental and the computational studies. The average error between the final in vitro vs. in silico aortic configurations, i.e., when the guidewire is fully inserted, are equal to 1.17, 1.22 and 1.40 mm, respectively, for Models A, B and C. The increasing trend in values of deformations from Model A to Model C was noticed both experimentally and numerically. The presented validated computational approach in combination with a tracking technology of the endovascular devices may be used to obtain the intra-operative configuration of the vessels and devices prior to the procedure, thus limiting the radiation exposure and the contrast agent dose.publishedVersio

Improved sequentially processed Cu(In,Ga)(S,Se)2 by Ag alloying

Alloying small quantities of silver into Cu(In,Ga)Se2 was shown to improve the efficiency for wide and low band gap solar cells. We study low band gap industrial Cu(In,Ga)(S,Se)2 absorbers, substituting less than 10% of the copper with silver, using absolute photoluminescence and cathodoluminescence spectroscopy. Silver improves the grain size and promotes the interdiffusion of Ga and In across the depth of the absorber, resulting in a smoother band gap gradient. However, a certain lateral inhomogeneity is observed near the front and back sides. The non-radiative losses in the bare absorbers are reduced by up to 30 meV

Photoluminescence assessment of materials for solar cell absorbers

Absolute photoluminescence measurements present a tool to predict the quality of photovoltaic absorber materials before finishing the solar cells. Quasi Fermi level splitting predicts the maximal open circuit voltage. However, various methods to extract quasi Fermi level splitting are plagued by systematic errors in the range of 10–20 meV. It is important to differentiate between the radiative loss and the shift of the emission maximum. They are not the same and when using the emission maximum as the “radiative” band gap to extract the quasi Fermi level splitting from the radiative efficiency, the quasi Fermi level splitting is 10 to 40 meV too low for a typical broadening of the emission spectrum. However, radiative efficiency presents an ideal tool to compare different materials without determining the quasi Fermi level splitting. For comparison with the open circuit voltage, a fit of the high energy slope to generalised Planck’s law gives more reliable results if the fitted temperature, i.e. the slope of the high energy part, is close to the actual measurement temperature. Generalised Planck’s law also allows the extraction of a non-absolute absorptance spectrum, which enables a comparison between the emission maximum energy and the absorption edge. We discuss the errors and the indications when they are negligible and when not

Rationale, component description and pilot evaluation of a physical health promotion measure for people with mental disorders across Europe

Introduction: The HELPS project aimed at developing a toolkit for the promotion of physical health in people with mental disorders to reduce the substantial excess morbidity and mortality in the target group. Methods: The HELPS toolkit was developed by means of national and international literature reviews, Delphi rounds with mental health experts and focus groups with mental health experts and patients/ residents in 14 European countries. The toolkit was translated into the languages of all participating countries, and usability of toolkit modules was tested. Results: The toolkit consists of several modules addressing diverse somatic health problems, lifestyle, environment issues, patient goals and motivation for health-promotion measures. It aims at empowering people with mental illness and staff to identify physical health risks in their specific contexts and to select the most appropriate modules from a range of health promotion tools. Discussion: The HELPS project used an integrative approach to the development of simple tools for the target population and is available online in 14 European languages. Preliminary evidence suggests that the toolkit can be used in routine care settings and should be put to test in controlled trials to reveal its potential impact

Improved Sequentially Processed Cu(In,Ga)(S,Se)2 by Ag Alloying

peer reviewedAlloying small quantities of silver into Cu(In,Ga)Se2 is shown to improve the efficiency for wide and low bandgap solar cells. Low bandgap industrial Cu(In,Ga)(S,Se)2 absorbers are studied, substituting less than 10% of the copper with silver, using absolute photoluminescence and cathodoluminescence spectroscopy. Silver improves the grain size and promotes the interdiffusion of Ga and In across the depth of the absorber, resulting in a smoother bandgap gradient. However, a certain lateral inhomogeneity is observed near the front and back sides. The nonradiative losses in the bare absorbers are reduced by up to 30 meV

Composition variations in Cu(In,Ga)(S,Se)2 solar cells: Not a gradient, but an interlaced network of two phases

peer reviewedRecord efficiency in chalcopyrite-based solar cells Cu(In,Ga)(S,Se)2 is achieved using a gallium gradient to increase the bandgap of the absorber toward the back side. Although this structure has successfully reduced recombination at the back contact, we demonstrate that in industrial absorbers grown in the pilot line of Avancis, the back part is a source of non-radiative recombination. Depth-resolved photoluminescence (PL) measurements reveal two main radiative recombination paths at 1.04 eV and 1.5–1.6 eV, attributed to two phases of low and high bandgap material, respectively. Instead of a continuous change in the bandgap throughout the thickness of the absorber, we propose a model where discrete bandgap phases interlace, creating an apparent gradient. Cathodoluminescence and Raman scattering spectroscopy confirm this result. Additionally, deep defects associated with the high gap phase reduce the absorber's performance. Etching away the back part of the absorber leads to an increase of one order of magnitude in the PL intensity, i.e., 60 meV in quasi-Fermi level splitting. Non-radiative voltage losses correlate linearly with the relative contribution of the high energy PL peak, suggesting that reducing the high gap phase could increase the open circuit voltage by up to 180 mV.POLC

It’s Doubled Edged: The Positive and Negative Relationships Between the Development of Moral Reasoning and Video Game Play Among Adolescents.

Due to the concerns over the effects of video game play, this study investigated adolescents’ moral development and their video game play. 166 adolescents aged 11-18 years (M = 13.08 SD = 1.91) attending an English school completed an online survey, which included a measure of moral development and questions regarding video game play. In contrast to previous research, male participants were found to have significantly (p = 0.02) higher moral reasoning scores than females. The results also suggested a transition in moral development, which takes place between the ages of 12–14. The results of moral development and video game played suggested both positive and negative relationships. Regression analysis suggested that there was a significant positive relationship between the more types of game genres played and higher moral scores. Although not significant, the results suggested trend for the following variables; years playing video games, mature content, engagement, moral narrative, Grand Theft Auto, Call of Duty, and length of time playing video games had a negative relationship with moral scores. The implications of these results are discussed with regards to moral education and the variables involved in video game play including the role content of video games

Résultats fonctionnels des anastomoses coloanales manuelles et colo-sus-anales mécaniques avec réservoir après proctectomie pour cancer du rectum (étude cas-témoin chez 41 malades)

But du travail : Après une proctectomie pour cancer du bas et moyen rectum, quand la marge distale de sécurité le permet, un choix est possible entre une anastomose coloanale manuelle (ACA) et une anastomose colo-sus-anal mécanique (ASCA). Le but de cette étude cas-témoins était de comparer le résultat fonctionnel de ces deux anastomoses. Méthodes : De 1997 à 2002, 20 malades avec un suivi supérieur à un an ont eu une ZCSA pour cancer (groupe ASCA). Ces 20 malades ont été appariés selon l'âge, le sexe, le risque ASA, l'existence d'une radiothérapie pré-opératoire, les gestes opératoires associés, la taille et le stade tumoral, à 21 malades ayant eu une ACA manuelle (groupe ACA). Dans tous les cas, un réservoir colique et une stomie de protection étaient réalisés. En cas d'ACSA, la longueur du moignon rectal restant était de 1.3 0.5 cm. Les résultats fonctionnels ont été évalués chez tous les malades à 6 et 12 mois. Résultats : La mortalité opératoire était nulle et la morbidité comparable dans les 2 groupes. La durée opératoire était de 293 55 min dans le groupe ACSA et de 330 54 dans le groupe ACA (p < 0.05). A un an, une continence parfaite était observée chez 16 malades (80 %) après ACSA et 14 (67 %) après ACA (NS). Le nombre de selles par jour était de 2.5 1.5 après ACSA et de 2 1 après ACA (NS). Il n'existait pas de différence significative entre les deux groupes pour le port de garniture, le nombre de selles nocturnes, le fractionnement des selles, la discrimination gaz/selle et l'utilisation d'un régime alimentaire ou d'un traitement freinateur du transit. Conclusions : Ce travail suggère qu'il ne semble pas exister de différence majeure pour le résultat fonctionnel entre les ACA et les ACSA. Comme l'ACSA nous paraît plus simple et est plus rapide à réaliser, elle nous semble devoir être préférée chaque fois que les impératifs carcinologiques et techniques le permettent.PARIS7-Xavier Bichat (751182101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF