Contribution à la compréhension de la fonctionnalisation mécanique de surface des composites à matrice thermoplastique (PEEK) destinés à l'assemblage par collage

L assemblage des matériaux composites thermoplastiques tel que le PEEK est l une des problématiques majeure de l industrie aéronautique. Actuellement, différentes techniques sont développées pour assurer l assemblage structural de ces matériaux, tels que : le soudage, le rivetage, le boulonnage et le collage. Les enjeux industriels majeurs sont principalement, à l heure actuelle, la conception des structures simplifiées au maximum afin de réduire les coûts de production et la réduction des consommations énergétiques. A cet effet, l industrie aéronautique fait fréquemment appel à l assemblage par collage en raison de nombreux avantages qu il offre (gain de poids, distribution régulière des contraintes, absence de trous) par rapport aux autres techniques existantes. Le PEEK (PolyEtherEtherKetone), est un matériau polymère semi-cristallin thermoplastique, à hautes performances. Ce matériau est souvent utilise dans l industrie aéronautique principalement renforce par des fibres de carbone ou de verre. Cependant, du fait du niveau élevé de sa résistance chimique l assemblage par collage du PEEK et de ses composites nécessitent des traitements de surfaces appropries et optimises. Or, afin d obtenir un system collé à haute performance, la problématique scientifique et technique doit être concentrée sur la jonction entre les éléments à assembler. En effet, la qualité de cette jonction est de la plus haute importance car elle doit permettre un transfert optimal des contraintes thermomécaniques lorsque l assemblage est soumis a ses conditions d'usage. Cette étude concerne donc, l amélioration des propriétés mécaniques (monotones et cycliques) de l assemblage par collage PEEK/PEEK. Dans cette optique, un traitement de surface simple de mise en œuvre est proposé. Ce traitement est le sablage, qui permet la modification topographique (morphologique) de surface. La compréhension des différents phénomènes d interaction aux interfaces intervenant dans l amélioration du comportement mécanique du joint de colle et qui s inscrit dans la triptyque : Rhéologie, Physico-chimie et topographie , est l enjeu scientifique majeur dans cette thèse. Dans un premier temps, l influence des paramètres du traitement tels que le temps de projection, la taille des particules, sur la morphologie de surface de différents matériaux à base de PEEK a été analysée, permettant ainsi d établir la corrélation entre les paramètres morphologiques et les mécanismes de modification topographique de surface intervenant pendant le traitement de surface. L un des facteurs clefs pour la compréhension des mécanismes d interaction entre l adhésif liquide et le substrat solide est la mouillabilité. L analyse du comportement au mouillage en fonction des différents paramètres du traitement a été réalisée. La mouillabilité des surfaces traitées est fortement affectée par la rugosité de surface créée après ce traitement. La relation entre les paramètres morphologiques et la mouillabilité a été discutée. Enfin, l influence des paramètres du traitement par sablage sur le comportement mécanique monotone et à long terme (essais de fatigue) sur la résistance du joint colle a été étudié à l aide d essais de cisaillement sur éprouvettes à simple recouvrement. Ceci a conduit, à la proposition de paramètres morphologiques surfaciques spécifiques pour l optimisation du comportement mécanique du joint de colle des matériaux composites à matrice PEEK.One of most problematic in the aeronautical industries is the structural joining of the high performance thermoplastic composites like PEEK composites. Actually, a lot of technologies are used for joining thermoplastic composites like welding, bolting, riveting, fastening and adhesive bonding. Due to the various advantages that characterize the adhesive bonding method, such an uniform stress distribution along the joint, weight light and cost reduction, makes this technique more desirable to join thermoplastic composites materials compared to the other joining techniques. PEEK (PolyEtherEtherKetone) is a semi crystalline thermoplastic material with high performance. This material is wildly used in aeronautical industries, principally, reinforced with carbon of glass fibres. However, its high chemical resistance makes the adhesive bonding of PEEK and its composites difficult and therefore an appropriate and optimised surface treatment is necessary. In the aim to obtain a bonded system with high performance, scientific and technical problematic should be focussed on the junction between adherents. Indeed, the quality of this junction is of utmost importance because it must allow optimum transfer of thermomechanical stresses when the assembly is subject to its terms of use. Though, at this time it is well known that thermoplastic composite materials are difficult to bond with out surface treatment. This study, therefore, relates to the improvement of mechanical properties (monotonic and cyclic) of the adhesive bonding system PEEK / PEEK. In this context, a surface treatment, easy to implement, is proposed. This surface treatment is sandblasting, which enables surface topographic (morphological) modifications. Understanding of various phenomena of interfaces interaction involved in the improvement of the mechanical behavior of the adhesive joint and is part of the triptych "Rheology, Physico chemistry and topography" is the major scientific challenge in this thesis. Initially, the influence of processing parameters such as the projection time, the particle size on surface morphology of various materials based on PEEK was analysed, thus allowing establishing the correlation between morphological parameters and modification mechanisms involved during surface treatment surface. One of the key factors for understanding the mechanisms of interaction between the liquid adhesive and the solid substrate is wettability. The analysis of the wetting behavior as a function of various parameters of the treatment was performed. The wettability of treated surfaces is strongly affected by surface roughness created after this treatment. The relationship between morphological parameters and wettability was discussed. Finally, the influence of sandblasting processing parameters on the mechanical behavior in monotoning and long term (fatigue tests) of the adhesive joint strength was studied, using single lap shear tests specimens. This has led to the proposal of specific surface morphological parameters for the optimization of the mechanical behavior of the adhesive joint of PEEK and its composites.LYON-Ecole Centrale (690812301) / SudocSudocFranceF

A fluorogenic cyclic peptide for imaging and quantification of drug-induced apoptosis

Programmed cell death or apoptosis is a central biological process that is dysregulated in many diseases, including inflammatory conditions and cancer. The detection and quantification of apoptotic cells in vivo is hampered by the need for fixatives or washing steps for non-fluorogenic reagents, and by the low levels of free calcium in diseased tissues that restrict the use of annexins. In this manuscript, we report the rational design of a highly stable fluorogenic peptide (termed Apo-15) that selectively stains apoptotic cells in vitro and in vivo in a calcium-independent manner and under wash-free conditions. Furthermore, using a combination of chemical and biophysical methods, we identify phosphatidylserine as a molecular target of Apo-15. We demonstrate that Apo-15 can be used for the quantification and imaging of drug-induced apoptosis in preclinical mouse models, thus creating opportunities for assessing the in vivo efficacy of anti-inflammatory and anti-cancer therapeutics

Comparing inequalities in the labour market from a segmentation perspective

Production of INCASI Project H2020-MSCA-RISE-2015 GA 691004The purpose of this chapter is to carry out a comparative analysis of labour markets in Europe and Latin America from the perspective of segmentation in order to explain the processes of social inequality that arise in the workplace, in light of recent trends in global socio-economic changes. The chapter proposes two main objectives. The first is to perform a comparative descriptive analysis of the main features of labour markets among 60 European and Latin American countries. The second objective is to propose a model of comparative analysis of labour inequality from the theoretical perspective of the segmentation of the labour market and structural heterogeneity. We will focus our analysis by selecting two countries, Spain and Argentina, which both underwent a late development of capitalism. The following general hypothesis is formulated: Spain and Argentina, having clearly differentiated features in economic structure, level of development, institutional frameworks and socio-historical processes, show common dynamics in the structuring of the capitalist labour market between a primary and secondary segment. Using equivalent databases on the workforce a typology of segmentation of employment is constructed that show, in addition to the specificities of each country, the similarities in the structuring of the labour market

Social Cognitive Role of Schizophrenia Candidate Gene GABRB2

10.1371/journal.pone.0062322PLoS ONE84

Social Memory and the Resilience of Communities Affected by Land Degradation

Based on evidence collected in 22 village communities from nine study sites situated in Spain, Italy, Greece, Morocco and China, this study analyses the complex interlinkages between social memory, community resilience and land degradation. Social memory is seen as an important explanation regarding the ability of a local community to manage and cope with land degradation. Emphasis is placed on the importance of three components of social memory – rites, traditions and social learning processes – for shaping community resilience in coping with land degradation processes. The study argues that, although there are subtle differences between the 22 village communities, the loss of social memory and learning pathways associated with managing land degradation is emerging as a critical factor constraining stakeholders from effectively responding to land degradation issue

INFOGEST static in vitro simulation of gastrointestinal food digestion

peer-reviewedSupplementary information is available at http://dx.doi.org/10.1038/s41596-018-0119-1 or https://www.nature.com/articles/s41596-018-0119-1#Sec45.Developing a mechanistic understanding of the impact of food structure and composition on human health has increasingly involved simulating digestion in the upper gastrointestinal tract. These simulations have used a wide range of different conditions that often have very little physiological relevance, and this impedes the meaningful comparison of results. The standardized protocol presented here is based on an international consensus developed by the COST INFOGEST network. The method is designed to be used with standard laboratory equipment and requires limited experience to encourage a wide range of researchers to adopt it. It is a static digestion method that uses constant ratios of meal to digestive fluids and a constant pH for each step of digestion. This makes the method simple to use but not suitable for simulating digestion kinetics. Using this method, food samples are subjected to sequential oral, gastric and intestinal digestion while parameters such as electrolytes, enzymes, bile, dilution, pH and time of digestion are based on available physiological data. This amended and improved digestion method (INFOGEST 2.0) avoids challenges associated with the original method, such as the inclusion of the oral phase and the use of gastric lipase. The method can be used to assess the endpoints resulting from digestion of foods by analyzing the digestion products (e.g., peptides/amino acids, fatty acids, simple sugars) and evaluating the release of micronutrients from the food matrix. The whole protocol can be completed in ~7 d, including ~5 d required for the determination of enzyme activities.COST action FA1005 INFOGEST (http://www.cost-infogest.eu/ ) is acknowledged for providing funding for travel, meetings and conferences (2011-2015). The French National Institute for Agricultural Research (INRA, www.inra.fr) is acknowledged for their continuous support of the INFOGEST network by organising and co-funding the International Conference on Food Digestion and workgroup meeting

A Systematic Review of the Prevalence of Schizophrenia

BACKGROUND: Understanding the prevalence of schizophrenia has important implications for both health service planning and risk factor epidemiology. The aims of this review are to systematically identify and collate studies describing the prevalence of schizophrenia, to summarize the findings of these studies, and to explore selected factors that may influence prevalence estimates. METHODS AND FINDINGS: Studies with original data related to the prevalence of schizophrenia (published 1965–2002) were identified via searching electronic databases, reviewing citations, and writing to authors. These studies were divided into “core” studies, “migrant” studies, and studies based on “other special groups.” Between- and within-study filters were applied in order to identify discrete prevalence estimates. Cumulative plots of prevalence estimates were made and the distributions described when the underlying estimates were sorted according to prevalence type (point, period, lifetime, and lifetime morbid risk). Based on combined prevalence estimates, the influence of selected key variables was examined (sex, urbanicity, migrant status, country economic index, and study quality). A total of 1,721 prevalence estimates from 188 studies were identified. These estimates were drawn from 46 countries, and were based on an estimated 154,140 potentially overlapping prevalent cases. We identified 132 core studies, 15 migrant studies, and 41 studies based on other special groups. The median values per 1,000 persons (10%–90% quantiles) for the distributions for point, period, lifetime, and lifetime morbid risk were 4.6 (1.9–10.0), 3.3 (1.3–8.2), 4.0 (1.6–12.1), and 7.2 (3.1–27.1), respectively. Based on combined prevalence estimates, we found no significant difference (a) between males and females, or (b) between urban, rural, and mixed sites. The prevalence of schizophrenia in migrants was higher compared to native-born individuals: the migrant-to-native-born ratio median (10%–90% quantile) was 1.8 (0.9–6.4). When sites were grouped by economic status, prevalence estimates from “least developed” countries were significantly lower than those from both “emerging” and “developed” sites (p = 0.04). Studies that scored higher on a quality score had significantly higher prevalence estimates (p = 0.02). CONCLUSIONS: There is a wealth of data about the prevalence of schizophrenia. These gradients, and the variability found in prevalence estimate distributions, can provide direction for future hypothesis-driven research

A systematic review of the incidence of schizophrenia: the distribution of rates and the influence of sex, urbanicity, migrant status and methodology

BACKGROUND: Understanding variations in the incidence of schizophrenia is a crucial step in unravelling the aetiology of this group of disorders. The aims of this review are to systematically identify studies related to the incidence of schizophrenia, to describe the key features of these studies, and to explore the distribution of rates derived from these studies. METHODS: Studies with original data related to the incidence of schizophrenia (published 1965–2001) were identified via searching electronic databases, reviewing citations and writing to authors. These studies were divided into core studies, migrant studies, cohort studies and studies based on Other Special Groups. Between- and within-study filters were applied in order to identify discrete rates. Cumulative plots of these rates were made and these distributions were compared when the underlying rates were sorted according to sex, urbanicity, migrant status and various methodological features. RESULTS: We identified 100 core studies, 24 migrant studies, 23 cohort studies and 14 studies based on Other Special Groups. These studies, which were drawn from 33 countries, generated a total of 1,458 rates. Based on discrete core data for persons (55 studies and 170 rates), the distribution of rates was asymmetric and had a median value (10%–90% quantile) of 15.2 (7.7–43.0) per 100,000. The distribution of rates was significantly higher in males compared to females; the male/female rate ratio median (10%–90% quantile) was 1.40 (0.9–2.4). Those studies conducted in urban versus mixed urban-rural catchment areas generated significantly higher rate distributions. The distribution of rates in migrants was significantly higher compared to native-born; the migrant/native-born rate ratio median (10%–90% quantile) was 4.6 (1.0–12.8). Apart from the finding that older studies reported higher rates, other study features were not associated with significantly different rate distributions (e.g. overall quality, methods related to case finding, diagnostic confirmation and criteria, the use of age-standardization and age range). CONCLUSIONS: There is a wealth of data available on the incidence of schizophrenia. The width and skew of the rate distribution, and the significant impact of sex, urbanicity and migrant status on these distributions, indicate substantial variations in the incidence of schizophrenia

Test of lepton universality in b→sℓ+ℓ−b \rightarrow s \ell^+ \ell^- decays

The first simultaneous test of muon-electron universality using $B^{+}\rightarrow K^{+}\ell^{+}\ell^{-}$ and $B^{0}\rightarrow K^{*0}\ell^{+}\ell^{-}$ decays is performed, in two ranges of the dilepton invariant-mass squared, $q^{2}$. The analysis uses beauty mesons produced in proton-proton collisions collected with the LHCb detector between 2011 and 2018, corresponding to an integrated luminosity of 9 $\mathrm{fb}^{-1}$. Each of the four lepton universality measurements reported is either the first in the given $q^{2}$ interval or supersedes previous LHCb measurements. The results are compatible with the predictions of the Standard Model.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-046.html (LHCb public pages