Découverte de «Plesiochelys», Chélonien marin-littoral, dans le Kimméridgien d’Alcobaça, Portugal

The presence of Craspedochelys (Plesiochelys s.l.) at Romão, Portugal, indicates that, in that country, the Thalassemydid dispersal began with the first occurrences of the group in Europe, in the late Kimmeridgian: communications existed between septentrional, atlantic and mesogean seas. The review of the family is considered

A model of defect cluster creation in fragmented cascades in metals based on morphological analysis

The impacts of ions and neutrons in metals cause cascades of atomic collisions that expand and shrink, leaving microstructure defect debris, i.e. interstitial or vacancy clusters or loops of different sizes. In De Backer et al (2016 Europhys. Lett. 115 26001), we described a method to detect the first morphological transition, i.e. the cascade fragmentation in subcascades, and a model of primary damage combining the binary collision approximation and molecular dynamics (MD). In this paper including W, Fe, Be, Zr and 20 other metals, we demonstrate that the fragmentation energy increases with the atomic number and decreases with the atomic density following a unique power law. Above the fragmentation energy, the cascade morphology can be characterized by the cross pair correlation functions of the multitype point pattern formed by the subcascades. We derive the numbers of pairs of subcascades and observed that they follow broken power laws. The energy where the power law breaks indicates the second morphological transition when cascades are formed by branches decorated by chaplets of small subcascades. The subcascade interaction is introduced in our model of primary damage by adding pairwise terms. Using statistics obtained on hundreds of MD cascades in Fe, we demonstrate that the interaction of subcascades increases the proportion of large clusters in the damage created by high energy cascades. Finally, we predict the primary damage of 500 keV Fe ion in Fe and obtain cluster size distributions when large statistics of MD cascades arc not feasible.Peer reviewe

A collinear-spin machine learned interatomic potential for Fe\textsubscript{7}Cr\textsubscript{2}Ni alloy

We have developed a new machine learned interatomic potential for the prototypical austenitic steel Fe$_{7}$Cr$_{2}$Ni, using the Gaussian approximation potential (GAP) framework. This new GAP can model the alloy's properties with higher accuracy than classical interatomic potentials like embedded atom models (EAM), while also allowing us to collect much more statistics than expensive first-principles methods like density functional theory (DFT). We also extended the GAP input descriptors to approximate the effects of collinear spins (Spin GAP), and demonstrate how this extended model successfully predicts low temperature structural distortions due to the antiferromagnetic spin state. We demonstrate the application of the Spin GAP model for bulk properties and vacancies and validate against DFT. These results are a step towards modelling ageing in austenitic steels with close to DFT accuracy but at a fraction of its cost

Ab initio study of the modification of elastic properties of alpha-iron by hydrostatic strain and by hydrogen interstitials

The effect of hydrostatic strain and of interstitial hydrogen on the elastic properties of $\alpha$-iron is investigated using \textit{ab initio} density-functional theory calculations. We find that the cubic elastic constants and the polycrystalline elastic moduli to a good approximation decrease linearly with increasing hydrogen concentration. This net strength reduction can be partitioned into a strengthening electronic effect which is overcome by a softening volumetric effect. The calculated hydrogen-dependent elastic constants are used to determine the polycrystalline elastic moduli and anisotropic elastic shear moduli. For the key slip planes in $\alpha$-iron, $[1\bar{1}0]$ and $[11\bar{2}]$, we find a shear modulus reduction of approximately 1.6% per at.% H.Comment: Updated first part of 1009.378

Cell-free (RNA) and cell-associated (DNA) HIV-1 and postnatal transmission through breastfeeding

<p>Introduction - Transmission through breastfeeding remains important for mother-to-child transmission (MTCT) in resource-limited settings. We quantify the relationship between cell-free (RNA) and cell-associated (DNA) shedding of HIV-1 virus in breastmilk and the risk of postnatal HIV-1 transmission in the first 6 months postpartum.</p> <p>Materials and Methods - Thirty-six HIV-positive mothers who transmitted HIV-1 by breastfeeding were matched to 36 non-transmitting HIV-1 infected mothers in a case-control study nested in a cohort of HIV-infected women. RNA and DNA were quantified in the same breastmilk sample taken at 6 weeks and 6 months. Cox regression analysis assessed the association between cell-free and cell-associated virus levels and risk of postnatal HIV-1 transmission.</p> <p>Results - There were higher median levels of cell-free than cell-associated HIV-1 virus (per ml) in breastmilk at 6 weeks and 6 months. Multivariably, adjusting for antenatal CD4 count and maternal plasma viral load, at 6 weeks, each 10-fold increase in cell-free or cell-associated levels (per ml) was significantly associated with HIV-1 transmission but stronger for cell-associated than cell-free levels [2.47 (95% CI 1.33–4.59) vs. aHR 1.52 (95% CI, 1.17–1.96), respectively]. At 6 months, cell-free and cell-associated levels (per ml) in breastmilk remained significantly associated with HIV-1 transmission but was stronger for cell-free than cell-associated levels [aHR 2.53 (95% CI 1.64–3.92) vs. 1.73 (95% CI 0.94–3.19), respectively].</p> <p>Conclusions - The findings suggest that cell-associated virus level (per ml) is more important for early postpartum HIV-1 transmission (at 6 weeks) than cell-free virus. As cell-associated virus levels have been consistently detected in breastmilk despite antiretroviral therapy, this highlights a potential challenge for resource-limited settings to achieve the UNAIDS goal for 2015 of eliminating vertical transmission. More studies would further knowledge on mechanisms of HIV-1 transmission and help develop more effective drugs during lactation.</p&gt

Disorder-Driven Pretransitional Tweed in Martensitic Transformations

Defying the conventional wisdom regarding first--order transitions, {\it solid--solid displacive transformations} are often accompanied by pronounced pretransitional phenomena. Generally, these phenomena are indicative of some mesoscopic lattice deformation that ``anticipates'' the upcoming phase transition. Among these precursive effects is the observation of the so-called ``tweed'' pattern in transmission electron microscopy in a wide variety of materials. We have investigated the tweed deformation in a two dimensional model system, and found that it arises because the compositional disorder intrinsic to any alloy conspires with the natural geometric constraints of the lattice to produce a frustrated, glassy phase. The predicted phase diagram and glassy behavior have been verified by numerical simulations, and diffraction patterns of simulated systems are found to compare well with experimental data. Analytically comparing to alternative models of strain-disorder coupling, we show that the present model best accounts for experimental observations.Comment: 43 pages in TeX, plus figures. Most figures supplied separately in uuencoded format. Three other figures available via anonymous ftp

Collinear-spin machine learned interatomic potential for Fe7Cr2Ni alloy

We have developed a machine learned interatomic potential for the prototypical austenitic steel Fe7Cr2Ni, using the Gaussian approximation potential (GAP) framework. This GAP can model the alloy's properties with close to density functional theory (DFT) accuracy, while at the same time allowing us to access larger length and time scales than expensive first-principles methods. We also extended the GAP input descriptors to approximate the effects of collinear spins (spin GAP), and demonstrate how this extended model successfully predicts structural distortions due to antiferromagnetic and paramagnetic spin states. We demonstrate the application of the spin GAP model for bulk properties and vacancies and validate against DFT. These results are a step towards modeling the atomistic origins of ageing in austenitic steels with higher accuracy

All-oral combination of oral vinorelbine and capecitabine as first-line chemotherapy in HER2-negative metastatic breast cancer: an International Phase II Trial

BACKGROUND: This multicentre, international phase II trial evaluated the efficacy and safety profile of a first-line combination of oral vinorelbine plus capecitabine for women with metastatic breast cancer (MBC). METHODS: Patients with measurable, HER2-negative disease received, as a first line in metastatic setting, 3-weekly cycles of oral vinorelbine 80 mg m(-2) (after a first cycle at 60) on day 1 and day 8, plus capecitabine 1000 mg m(-2) (750 if >or=65 years of age) twice daily, on days 1-14. Treatment was continued until progression or unacceptable toxicity. RESULTS: A total of 55 patients were enrolled and 54 were treated (median age: 58.5 years). Most (78%) had visceral involvement and 63% had received earlier (neo)adjuvant chemotherapy. The objective response rate (RECIST) in 49 evaluable patients was 51% (95% confidence interval (CI), 36-66), including complete response in 4%. The clinical benefit rate (response or stable disease for >or=6 months) was 63% (95% CI, 48-77). The median duration of response was 7.2 months (95% CI, 6.4-10.2). After a median follow-up of 41 months, median progression-free survival was 8.4 months (95% CI, 5.8-9.7) and median overall survival was 29.2 months (95% CI, 18.2-40.1). Treatment-related adverse events were manageable, the main grade 3-4 toxicity was neutropaenia (49%); two patients experienced febrile neutropaenia and three patients had a neutropaenic infection (including one septic death). A particularly low rate of alopaecia was observed. CONCLUSION: These results show that the all-oral combination of oral vinorelbine and capecitabine is an effective and well-tolerated first-line regimen for MB

Metabolic and Innate Immune Cues Merge into a Specific Inflammatory Response via the UPR

Erratum in : Metabolic and Innate Immune Cues Merge into a Specific Inflammatory Response via the UPR. [Cell. 2019]International audienceInnate immune responses are intricately linked with intracellular metabolism of myeloid cells. Toll-likereceptor (TLR) stimulation shifts intracellular metabolism toward glycolysis, while anti-inflammatorysignals depend on enhanced mitochondrial respiration. How exogenous metabolic signals affect theimmune response is unknown. We demonstrate that TLR-dependent responses of dendritic cells (DC)are exacerbated by a high fatty acid (FA) metabolic environment. FA suppress the TLR-inducedhexokinase activity and perturb tricarboxylic acid cycle metabolism. These metabolic changesenhance mitochondrial reactive oxygen species (mtROS) production and, in turn, the unfolded proteinresponse (UPR) leading to a distinct transcriptomic signature, with IL-23 as hallmark. Interestingly,chemical or genetic suppression of glycolysis was sufficient to induce this specific immune response.Conversely, reducing mtROS production or DC-specific deficiency in XBP1 attenuated IL-23expression and skin inflammation in an IL-23-dependent model of psoriasis. Thus, fine-tuning of innateimmunity depends on optimization of metabolic demands and minimization of mtROS-induced UPR

Recent advances in modeling and simulation of the exposure and response of tungsten to fusion energy conditions

Under the anticipated operating conditions for demonstration magnetic fusion reactors beyond ITER, structural and plasma-facing materials will be exposed to unprecedented conditions of irradiation, heat flux, and temperature. While such extreme environments remain inaccessible experimentally, computational modeling and simulation can provide qualitative and quantitative insights into materials response and complement the available experimental measurements with carefully validated predictions. For plasma-facing components such as the first wall and the divertor, tungsten (W) has been selected as the leading candidate material due to its superior high-temperature and irradiation properties, as well as for its low retention of implanted tritium. In this paper we provide a review of recent efforts in computational modeling of W both as a plasma-facing material exposed to He deposition as well as a bulk material subjected to fast neutron irradiation. We use a multiscale modeling approach-commonly used as the materials modeling paradigm-to define the outline of the paper and highlight recent advances using several classes of techniques and their interconnection. We highlight several of the most salient findings obtained via computational modeling and point out a number of remaining challenges and future research directions.Peer reviewe