Reversible Rail Shear Apparatus Applied to the Study of Woven Laminate Shear Behavior

The multitude of in-plane shear tests existing in the literature seems to demonstrate the complexity of developing a test adapted to all experimental works. In a general framework of investigation of translaminar cracks in thin laminates, a test able to reproduce a pure in-plane shear loading was required. The laminate studied is notably employed as helicopter blade skin, and cyclic torsion induced by aerodynamic load involves cyclic in-plane shear. This particular application established some specifications for the test needed to carry out this study. To comply with them, an original technological solution has been developed from a three-rail shear test apparatus. This paper describes the resulting “reversible rail shear test” solution and its application to the study of in-plane shear behavior of a thin glass-epoxy laminate. The results concern plain and notched coupons under quasi-static loading, and crack growth tests under cyclic loading

Propagation de coupure en fatigue sur composites tissés Etude expérimentale et modélisation

Les pales d hélicoptère sont des structures composites soumises à un chargement cyclique multiaxial, et leur criticité impose de porter une attention particulière à la tolérance aux dommages. Leur revêtement peut potentiellement présenter des criques suite à certains évènements (impact, défaut, foudre). Ces travaux se focalisent sur un matériau de revêtement donné (tissu de verre) et concernent l étude de la propagation de coupure (crique) sous chargement cyclique. Les sollicitations de service ont amené à considérer la traction et le cisaillement plan. Une étude expérimentale a été menée afin d étudier les modes d endommagement du matériau et sa résistance à la propagation de coupure pour différentes sollicitations (en traction et en cisaillement) et pour les drapages les plus courants. Elle a permis de dégager les mécanismes d endommagement mis en jeu, et a fourni un ensemble important de propriétés matériau et de données quantitatives de vitesse de propagation. Elle a par ailleurs guidé vers une modélisation par éléments finis adaptée à l architecture du matériau, et la manière dont il se dégrade en fatigue. Ce modèle repose sur un maillage à l échelle de la mèche, et la prédiction de la propagation est obtenue par l utilisation d une courbe de fatigue S-N. La simulation a été évaluée par comparaison des faciès de rupture, des vitesses de propagation et de l étendue des zones d endommagement avec les essais réalisés sur éprouvettes.Helicopter blades consist of composite structures which have to sustain multi-axial cyclic loading. Because of their criticality, damage tolerance has to be considered carefully. Their skin is subjected to environmental events like impact, flaw, lightning which can cause through-thethickness cracks. The present work focuses on one given skin material (woven glass fabric) and concerns the study of the through-the-thickness crack growth under cyclic loading. In-flight loading lead to consider tension and shear. An experimental study has been carried out to study damage in the material and its crackgrowth resistance under different loadings (tension and shear) and for usual stacking sequences. It highlighted damage mechanisms and provided an important set of material data and crack growth speeds. Besides, this led to a finite element approach adapted to the woven fabric architecture, anddamage feature under fatigue loading. This modeling is based on a bundle scale mesh, a semidiscrete damage modeling and an S-N curve to predict fiber failure. Numerical simulations of crack growth tests were carried out, and results were compared with experiments in terms of crack direction, crack growth speed, and size of damaged area.TOULOUSE-ISAE (315552318) / SudocSudocFranceF

Ebf1 or Pax5 haploinsufficiency synergizes with STAT5 activation to initiate acute lymphoblastic leukemia

STAT5 is abnormally activated in patients with acute lymphoblastic leukemia, and increased STAT5 activation synergizes with PAX5 and EBF1 to induce disease

Developing a community-based genetic nomenclature for anole lizards

Background: Comparative studies of amniotes have been hindered by a dearth of reptilian molecular sequences. With the genomic assembly of the green anole, Anolis carolinensis available, non-avian reptilian genes can now be compared to mammalian, avian, and amphibian homologs. Furthermore, with more than 350 extant species in the genus Anolis, anoles are an unparalleled example of tetrapod genetic diversity and divergence. As an important ecological, genetic and now genomic reference, it is imperative to develop a standardized Anolis gene nomenclature alongside associated vocabularies and other useful metrics. Results: Here we report the formation of the Anolis Gene Nomenclature Committee (AGNC) and propose a standardized evolutionary characterization code that will help researchers to define gene orthology and paralogy with tetrapod homologs, provide a system for naming novel genes in Anolis and other reptiles, furnish abbreviations to facilitate comparative studies among the Anolis species and related iguanid squamates, and classify the geographical origins of Anolis subpopulations. Conclusions: This report has been generated in close consultation with members of the Anolis and genomic research communities, and using public database resources including NCBI and Ensembl. Updates will continue to be regularly posted to new research community websites such as lizardbase. We anticipate that this standardized gene nomenclature will facilitate the accessibility of reptilian sequences for comparative studies among tetrapods and will further serve as a template for other communities in their sequencing and annotation initiatives.Organismic and Evolutionary BiologyOther Research Uni

Identification of methylated deoxyadenosines in vertebrates reveals diversity in DNA modifications.

Methylation of cytosine deoxynucleotides generates 5-methylcytosine (m(5)dC), a well-established epigenetic mark. However, in higher eukaryotes much less is known about modifications affecting other deoxynucleotides. Here, we report the detection of N(6)-methyldeoxyadenosine (m(6)dA) in vertebrate DNA, specifically in Xenopus laevis but also in other species including mouse and human. Our methylome analysis reveals that m(6)dA is widely distributed across the eukaryotic genome and is present in different cell types but is commonly depleted from gene exons. Thus, direct DNA modifications might be more widespread than previously thought.M.J.K. was supported by the Long-Term Human Frontiers Fellowship (LT000149/2010-L), the Medical Research Council grant (G1001690), and by the Isaac Newton Trust Fellowship (R G76588). The work was sponsored by the Biotechnology and Biological Sciences Research Council grant BB/M022994/1 (J.B.G. and M.J.K.). The Gurdon laboratory is funded by the grant 101050/Z/13/Z (J.B.G.) from the Wellcome Trust, and is supported by the Gurdon Institute core grants, namely by the Wellcome Trust Core Grant (092096/Z/10/Z) and by the Cancer Research UK Grant (C6946/A14492). C.R.B. and G.E.A. are funded by the Wellcome Trust Core Grant. We are grateful to D. Simpson and R. Jones-Green for preparing X. laevis eggs and oocytes, F. Miller for providing us with M. musculus tissue, T. Dyl for X. laevis eggs and D. rerio samples, and to Gurdon laboratory members for their critical comments. We thank U. Ruether for providing us with M. musculus kidney DNA (Entwicklungs- und Molekularbiologie der Tiere, Heinrich Heine Universitaet Duesseldorf, Germany). We also thank J. Ahringer, S. Jackson, A. Bannister and T. Kouzarides for critical input and advice, M. Sciacovelli and E. Gaude for suggestions.This is the author accepted manuscript. The final version is available from Nature Publishing Group via http://dx.doi.org/10.1038/nsmb.314

Climate change is catchy ? but when will it really hurt?

Concern and general awareness about the impacts of climate change in all sectors of the social-ecological-economic system is growing as a result of improved climate science products and information, as well as increased media coverage of the apparent manifestations of the phenomenon in our society. However, scales of climate variability and change, in space and time, are often confused and so attribution of impacts on various sectors, including the health sector, can be misunderstood and misrepresented. In this review, we assess the mechanistic links between climate and infectious diseases in particular, and consider how this relationship varies, and may vary according to different time scales, especially for aetiologically climate-linked diseases. While climate varies in the medium (inter-annual) time frame, this variability itself may be oscillating and/or trending on cyclical and long-term (climate change) scales because of regional and global scale climate phenomena such as the El-Nino southern oscillation coupled with global-warming drivers of climate change. As several studies have shown, quantifying and modelling these linkages and associations at appropriate time and space scales is both necessary and increasingly feasible with improved climate science products and better epidemiological data. The application of this approach is considered for South Africa, and the need for a more concerted effort in this regard is supported

The Chemistry of the Postpharyngeal Gland of Female European Beewolves

Females of the European beewolf, Philanthus triangulum, possess a large glove-shaped gland in the head, the postpharyngeal gland (PPG). They apply the content of the PPG to their prey, paralyzed honeybees, where it delays fungal infestation. Here, we describe the chemical composition of the gland by using combined GC-MS, GC-FTIR, and derivatization. The PPG of beewolves contains mainly long-chain unsaturated hydrocarbons (C23–C33), lower amounts of saturated hydrocarbons (C14–C33), and minor amounts of methyl-branched hydrocarbons (C17–C31). Additionally, the hexane-soluble gland content is comprised of small amounts of an unsaturated C25 alcohol, an unknown sesquiterpene, an octadecenylmethylester, and several long-chain saturated (C25, C27) and unsaturated (C23–C27) ketones, some of which have not yet been reported as natural products. Surprisingly, we found a dimorphism with regard to the major component of the PPG with some females having (Z)-9-pentacosene, whereas others have (Z)-9-heptacosene as their predominant component. The biological relevance of the compounds for the prevention of fungal growth on the prey and the significance of the chemical dimorphism are discussed

Poly-p-phenylenevinylene-g-poly(2-(methacryloyloxy)ethyl) trimethylammonium chloride (PPV-g-PMETAC): a fluorescent, water-soluble, selective anion sensor

The photophysical and ion-sensing properties of densely grafted conjugated polymer poly-p-phenylenevinylene-g-poly(2-(methacryloyloxy)ethyl)trimethylammonium chloride (PPV-g-PMETAC) are presented herein. The grafted polymer exhibits excellent iodide-sensing which is easily observed using fluorescence spectroscopy. The iodide detection limit for PPV-g-PMETAC was found to be 10 nM and was independent of temperature and pH less than 12. The change in fluorescence of PPV-g-PMETAC, upon exposure to iodide, was attributed to polymer aggregation due to changes in the morphology of the grafted PMETAC side chains, which was observed using atomic force microscopic and dynamic light scattering studies

Pathways to understanding the genomic aetiology of osteoarthritis

Osteoarthritis is a common, complex disease with no curative therapy. In this review, we summarize current knowledge on disease aetiopathogenesis and outline genetics and genomics approaches that are helping catalyse a much-needed improved understanding of the biological underpinning of disease development and progression

Rapid Evolution of Sex Pheromone-Producing Enzyme Expression in Drosophila

Rapid evolution of gene expression patterns responsible for pheromone production in 24 species of Drosophila was mapped to simple mutations within the regulatory domain of the desatF gene