Transverse-mode selective resonant grating-mirrors for high power and high brightness emission

International audienceThe finite angular spectral width of a 2D resonant grating mirror is adjusted to select the fundamental transverse mode of a laser and to filter out higher order modes. The selection principle is explained phenomenologically on a simplified 1D model. The 2D design is made so as to sustain the large field concentration in the grating slab-waveguide mirror, and the technology permitting to obtain the resonant reflection within the gain bandwidth of two types of laser is described. The blank experimental measurements by means of a white light supercontinuum are shown to match the targeted specifications on the resonance spectral position and angular width

Li/Mg systematics in scleractinian corals: Calibration of the thermometer

We show that the Li/Mg systematics of a large suite of aragonitic coral skeletons, representing a wide range of species inhabiting disparate environments, provides a robust proxy for ambient seawater temperature. The corals encompass both zooxanthellate and azooxanthellate species (Acropora sp., Porites sp., Cladocora caespitosa, Lophelia pertusa, Madrepora oculata and Flabellum impensum) collected from shallow, intermediate, and deep-water habitats, as well as specimens cultured in tanks under temperature-controlled conditions. The Li/Mg ratios observed in corals from these diverse tropical, temperate, and deep-water environments are shown to be highly correlated with temperature, giving an exponential temperature relationship of: Li/Mg (mmol/mol) = 5.41 exp (−0.049 * T) (r² = 0.975, n = 49). Based on the standard error of the Li/Mg versus temperature correlation, we obtain a typical precision of ±0.9 °C for the wide range of species analysed, similar or better than that of other less robust coral temperature proxies such as Sr/Ca ratios.The robustness and species independent character of the Li/Mg temperature proxy is shown to be the result of the normalization of Li to Mg, effectively eliminating the precipitation efficiency component such that temperature remains as the main controller of coral Li/Mg compositions. This is inferred from analysis of corresponding Li/Ca and Mg/Ca ratios with both ratios showing strong microstructure-related co-variations between the fibrous aragonite and centres of calcification, a characteristic that we attribute to varying physiological controls on growth rate. Furthermore, Li/Ca ratios show an offset between more rapidly growing zooxanthellate and azooxanthellate corals, and hence only an approximately inverse relationship to seawater temperature. Mg/Ca ratios show very strong physiological controls on growth rate but no significant dependence with temperature, except possibly for Acropora sp. and Porites sp. A strong positive correlation is nevertheless found between Li/Ca and Mg/Ca ratios at similar temperatures, indicating that both Li and Mg are subject to control by similar growth mechanisms, specifically the mass fraction of aragonite precipitated during calcification, which is shown to be consistent with a Rayleigh-based elemental fractionation model.The highly coherent array defined by Li/Mg versus temperature is thus largely independent of coral calcification mechanisms, with the strong temperature dependence reflecting the greater sensitivity of the KdLi/Ca partition coefficient relative to KdMg/Ca. Accordingly, Li/Mg ratios exhibit a highly coherent exponential correlation with temperature, thereby providing a more robust tool for reconstructing paleo-seawater temperatures

Genomic analysis of an emerging multiresistant Staphylococcus aureus strain rapidly spreading in cystic fibrosis patients revealed the presence of an antibiotic inducible bacteriophage

BACKGROUND: Staphylococcus aureus is a major human pathogen responsible for a variety of nosocomial and community-acquired infections. Recent reports show that the prevalence of Methicillin-Resistant S. aureus (MRSA) infections in cystic fibrosis (CF) patients is increasing. In 2006 in Marseille, France, we have detected an atypical MRSA strain with a specific antibiotic susceptibility profile and a unique growth phenotype. Because of the clinical importance of the spread of such strain among CF patients we decided to sequence the genome of one representative isolate (strain CF-Marseille) to compare this to the published genome sequences. We also conducted a retrospective epidemiological analysis on all S. aureus isolated from 2002 to 2007 in CF patients from our institution. RESULTS: CF-Marseille is multidrug resistant, has a hetero-Glycopeptide-Intermediate resistance S. aureus phenotype, grows on Cepacia agar with intense orange pigmentation and has a thickened cell wall. Phylogenetic analyses using Complete Genome Hybridization and Multi Locus VNTR Assay showed that CF-Marseille was closely related to strain Mu50, representing vancomycin-resistant S. aureus. Analysis of CF-Marseille shows a similar core genome to that of previously sequenced MRSA strains but with a different genomic organization due to the presence of specific mobile genetic elements i.e. a new SCCmec type IV mosaic cassette that has integrated the pUB110 plasmid, and a new phage closely related to phiETA3. Moreover this phage could be seen by electron microscopy when mobilized with several antibiotics commonly used in CF patients including, tobramycin, ciprofloxacin, cotrimoxazole, or imipenem. Phylogenetic analysis of phenotypically similar h-GISA in our study also suggests that CF patients are colonized by polyclonal populations of MRSA that represents an incredible reservoir for lateral gene transfer. CONCLUSION: In conclusion, we demonstrated the emergence and spreading of a new isolate of MRSA in CF patients in Marseille, France, that has probably been selected in the airways by antibiotic pressure. Antibiotic-mediated phage induction may result in high-frequency transfer and the unintended consequence of promoting the spread of virulence and/or antibiotic resistance determinants. The emergence of well-adapted MRSA is worrying in such population chronically colonized and receiving many antibiotics and represents a model for emergence of uncontrollable super bugs in a specific niche. REVIEWERS: This article was reviewed by Eric Bapteste, Pierre Pontarotti, and Igor Zhulin. For the full reviews, please go to the Reviewers' comments section

In Situ Fe and S isotope analyses in pyrite from the 3.2 Ga Mendon Formation (Barberton Greenstone Belt, South Africa): Evidence for early microbial iron reduction

International audienceOn the basis of phylogenetic studies and laboratory cultures, it has been proposed that the ability of microbes to metabolize iron has emerged prior to the Archaea/ Bacteria split. However, no unambiguous geochemical data supporting this claim have been put forward in rocks older than 2.7-2.5 giga years (Gyr). In the present work, we report in situ Fe and S isotope composition of pyrite from 3.28-to 3.26-Gyr-old cherts from the upper Mendon Formation, South Africa. We identified three populations of microscopic pyrites showing a wide range of Fe isotope compositions, which cluster around two δ 56 Fe values of −1.8‰ and +1‰. These three pyrite groups can also be distinguished based on the pyrite crystallinity and the S isotope mass-independent signatures. One pyrite group displays poorly crystallized pyrite minerals with positive Δ 33 S values > +3‰, while the other groups display more variable and closer to 0‰ Δ 33 S values with recrystallized pyrite rims. It is worth to note that all the pyrite groups display positive Δ 33 S values in the pyrite core and similar trace element compositions

Society-based solutions to coral reef threats in french pacific territories

This article reviews the state of coral reefs in French Pacific territories in the context of global change (especially threats linked to climate change). We first outline the specific local characteristics, vulnerabilities, and threats faced by the coral reefs of New Caledonia, French Polynesia and Wallis and Futuna. We also emphasize local and other human communities' economic and cultural reliance on coral reefs. Secondly, we discuss the natural and anthropogenic threats facing coral reefs in French Pacific territories, and current ecological responses such as mitigation and adaptation strategies. We conclude by proposing socio-economic solutions for the Pacific region across varying scales, with a special focus on enforcement measures and socio-political issues

Training the next generation of plastics pollution researchers: tools, skills and career perspectives in an interdisciplinary and transdisciplinary field

Plastics pollution research attracts scientists from diverse disciplines. Many Early Career Researchers (ECRs) are drawn to this field to investigate and subsequently mitigate the negative impacts of plastics. Solving the multi-faceted plastic problem will always require breakthroughs across all levels of science disciplinarity, which supports interdisciplinary discoveries and underpins transdisciplinary solutions. In this context, ECRs have the opportunity to work across scientific discipline boundaries and connect with different stakeholders, including industry, policymakers and the public. To fully realize their potential, ECRs need to develop strong communication and project management skills to be able to effectively interface with academic peers and non-academic stakeholders. At the end of their formal education, many ECRs will choose to leave academia and pursue a career in private industry, government, research institutes or non-governmental organizations (NGOs). Here we give perspectives on how ECRs can develop the skills to tackle the challenges and opportunities of this transdisciplinary research field and how these skills can be transferred to different working sectors. We also explore how advisors can support an ECRs’ growth through inclusive leadership and coaching. We further consider the roles each party may play in developing ECRs into mature scientists by helping them build a strong foundation, while also critically assessing problems in an interdisciplinary and transdisciplinary context. We hope these concepts can be useful in fostering the development of the next generation of plastics pollution researchers so they can address this global challenge more effectively

Targeted long-read sequencing of the Ewing sarcoma 6p25.1 susceptibility locus identifies germline-somatic interactions with EWSR1-FLI1 binding

Ewing sarcoma (EwS) is a rare bone and soft tissue malignancy driven by chromosomal translocations encoding chimeric transcription factors, such as EWSR1-FLI1, that bind GGAA motifs forming novel enhancers that alter nearby expression. We propose that germline microsatellite variation at the 6p25.1 EwS susceptibility locus could impact downstream gene expression and EwS biology. We performed targeted long-read sequencing of EwS blood DNA to characterize variation and genomic features important for EWSR1-FLI1 binding. We identified 50 microsatellite alleles at 6p25.1 and observed that EwS-affected individuals had longer alleles (>135 bp) with more GGAA repeats. The 6p25.1 GGAA microsatellite showed chromatin features of an EWSR1-FLI1 enhancer and regulated expression of RREB1, a transcription factor associated with RAS/MAPK signaling. RREB1 knockdown reduced proliferation and clonogenic potential and reduced expression of cell cycle and DNA replication genes. Our integrative analysis at 6p25.1 details increased binding of longer GGAA microsatellite alleles with acquired EWSR-FLI1 to promote Ewing sarcomagenesis by RREB1-mediated proliferation

Genetic landscape of a large cohort of Primary Ovarian Insufficiency : New genes and pathways and implications for personalized medicine

Background Primary Ovarian Insufficiency (POI), a public health problem, affects 1-3.7% of women under 40 yield-ing infertility and a shorter lifespan. Most causes are unknown. Recently, genetic causes were identified, mostly in single families. We studied an unprecedented large cohort of POI to unravel its molecular pathophysiology.Methods 375 patients with 70 families were studied using targeted (88 genes) or whole exome sequencing with pathogenic/likely-pathogenic variant selection. Mitomycin-induced chromosome breakages were studied in patients' lymphocytes if necessary. Findings A high-yield of 29.3% supports a clinical genetic diagnosis of POI. In addition, we found strong evidence of pathogenicity for nine genes not previously related to a Mendelian phenotype or POI: ELAVL2, NLRP11, CENPE, SPATA33, CCDC150, CCDC185, including DNA repair genes: C17orf53(HROB), HELQ, SWI5 yielding high chromo-somal fragility. We confirmed the causal role of BRCA2, FANCM, BNC1, ERCC6, MSH4, BMPR1A, BMPR1B, BMPR2, ESR2, CAV1, SPIDR, RCBTB1 and ATG7 previously reported in isolated patients/families. In 8.5% of cases, POI is the only symptom of a multi-organ genetic disease. New pathways were identified: NF-kB, post-translational regulation, and mitophagy (mitochondrial autophagy), providing future therapeutic targets. Three new genes have been shown to affect the age of natural menopause supporting a genetic link.Interpretation We have developed high-performance genetic diagnostic of POI, dissecting the molecular pathogene-sis of POI and enabling personalized medicine to i) prevent/cure comorbidities for tumour/cancer susceptibility genes that could affect life-expectancy (37.4% of cases), or for genetically-revealed syndromic POI (8.5% of cases), ii) predict residual ovarian reserve (60.5% of cases). Genetic diagnosis could help to identify patients who may benefit from the promising in vitro activation-IVA technique in the near future, greatly improving its success in treating infertility.Funding Universite? Paris Saclay, Agence Nationale de Biome?decine.Copyright (c) 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)Peer reviewe

Low-frequency variation near common germline susceptibility loci are associated with risk of Ewing sarcoma

Background: Ewing sarcoma (EwS) is a rare, aggressive solid tumor of childhood, adolescence and young adulthood associated with pathognomonic EWSR1-ETS fusion oncoproteins altering transcriptional regulation. Genome-wide association studies (GWAS) have identified 6 common germline susceptibility loci but have not investigated low-frequency inherited variants with minor allele frequencies below 5% due to limited genotyped cases of this rare tumor. Methods We investigated the contribution of rare and low-frequency variation to EwS susceptibility in the largest EwS genome-wide association study to date (733 EwS cases and 1,346 unaffected controls of European ancestry). Results We identified two low-frequency variants, rs112837127 and rs2296730, on chromosome 20 that were associated with EwS risk (OR = 0.186 and 2.038, respectively;P-value < 5x10(-8)) and located near previously reported common susceptibility loci. After adjusting for the most associated common variant at the locus, only rs112837127 remained a statistically significant independent signal (OR = 0.200, P-value = 5.84x10(-8)). Conclusions: These findings suggest rare variation residing on common haplotypes are important contributors to EwS risk. Impact Motivate future targeted sequencing studies for a comprehensive evaluation of low-frequency and rare variation around common EwS susceptibility loci

Energy Resolution Performance of the CMS Electromagnetic Calorimeter

The energy resolution performance of the CMS lead tungstate crystal electromagnetic calorimeter is presented. Measurements were made with an electron beam using a fully equipped supermodule of the calorimeter barrel. Results are given both for electrons incident on the centre of crystals and for electrons distributed uniformly over the calorimeter surface. The electron energy is reconstructed in matrices of 3 times 3 or 5 times 5 crystals centred on the crystal containing the maximum energy. Corrections for variations in the shower containment are applied in the case of uniform incidence. The resolution measured is consistent with the design goals