Species separation and modification of neutron diagnostics in inertial-confinement fusion

The different behaviours of deuterium (D) and tritium (T) in the hot spot of marginally-igniting cryogenic DT inertial-confinement fusion (ICF) targets are investigated with an ion Fokker-Planck model. With respect to an equivalent single-species model, a higher density and a higher temperature are found for T in the stagnation phase of the target implosion. In addition, the stagnating hot spot is found to be less dense but hotter than in the single-species case. As a result, the fusion reaction yield in the hot spot is significantly increased. Fusion neutron diagnostics of the implosion find a larger ion temperature as deduced from DT reactions than from DD reactions, in good agreement with NIF experimental results. ICF target designs should thus definitely take ion-kinetic effects into account

The Dual Origin Of The Nitrogen Deficiency In Comets: Selective Volatile Trapping In The Nebula And Postaccretion Radiogenic Heating

We propose a scenario that explains the apparent nitrogen deficiency in comets in away that is consistent with the fact that the surfaces of Pluto and Triton are dominated by nitrogen-rich ice. We use a statistical thermodynamic model to investigate the composition of the successive multiple guest clathrates that may have formed during the cooling of the primordial nebula from the most abundant volatiles present in the gas phase. These clathrates agglomerated with the other ices (pure condensates or stoichiometric hydrates) and formed the building blocks of comets. We report that molecular nitrogen is a poor clathrate former, when we consider a plausible gas-phase composition of the primordial nebula. This implies that its trapping into cometesimals requires a low disk temperature (similar to 20 K) in order to allow the formation of its pure condensate. We find that it is possible to explain the lack of molecular nitrogen in comets as a consequence of their postformation internal heating engendered by the decay of short-lived radiogenic nuclides. This scenario is found to be consistent with the presence of nitrogen-rich ice covers on Pluto and Triton. Our model predicts that comets should present xenon-to-water and krypton-to-water ratios close to solar xenon-to-oxygen and krypton-to-oxygen ratios, respectively. In contrast, the argon-to-water ratio is predicted to be depleted by a factor of similar to 300 in comets compared to solar argon-to-oxygen, as a consequence of poor trapping efficiency and radiogenic heating.CNESJPLAstronom

Non-equilibrium quantum magnetism in a dipolar lattice gas

Research on quantum magnetism with ultra-cold gases in optical lattices is expected to open fascinating perspectives for the understanding of fundamental problems in condensed-matter physics. Here we report on the first realization of quantum magnetism using a degenerate dipolar gas in an optical lattice. In contrast to their non-dipolar counterparts, dipolar lattice gases allow for inter-site spin-spin interactions without relying on super-exchange energies, which constitutes a great advantage for the study of spin lattice models. In this paper we show that a chromium gas in a 3D lattice realizes a lattice model resembling the celebrated t-J model, which is characterized by a non-equilibrium spinor dynamics resulting from inter-site Heisenberg-like spin-spin interactions provided by non-local dipole-dipole interactions. Moreover, due to its large spin, chromium lattice gases constitute an excellent environment for the study of quantum magnetism of high-spin systems, as illustrated by the complex spin dynamics observed for doubly-occupied sites.Comment: 10 pages, 5+5 figure

To what extent are bryophytes efficient dispersers?

1. Bryophytes are typically seen as extremely efficient dispersers. Experimental evidence suggests that efficient short-distance dispersal coupled with random long-distance dispersal (LDD) leads to an inverse isolation effect. Under the latter, a higher genetic diversity of colonizing propagules is expected with increasing isolation, counteracting differentiation beyond the range of short-distance dispersal. 2. This expectation is tested from a review of evidence on spatial genetic structure and analyses of isolation-by-distance (IBD) at different scales. 3. A decay of the IBD signal, characterized by non-significant slopes between kinship coefficients and geographic distance was observed beyond 100 m. A second slope shift was observed at distances larger than 1 km, with a proportion of significant slopes in more than one third of the datasets. 4. The decay of the IBD signal beyond 100 m, which reflects efficient LDD, is consistent with the inverse isolation hypothesis. Persistence of a significant IBD signal at medium ranges in one third of the analysed cases suggests, however, that the inverse isolation effect is not a rule in bryophyte spore dispersal. Furthermore, the higher proportion of significant IBD patterns observed at scales over 100 km likely marks the limits of regional dispersal, beyond which an increasingly smaller proportion of spores travel. 5. Synthesis. We discuss the differences between experimental and genetic estimates of spore dispersal and conclude that geographic distance remains a significant proxy of spore colonization rates, with major consequences for our understanding of actual migration capacities in bryophytes, and hence, our capacity to model range shifts in a changing world.Peer reviewe

A stepwise breakdown of B-cell tolerance occurs within renal allografts during chronic rejection

Autoantibodies detected after kidney transplantation may contribute to chronic rejection. We and others have previously described the organization of immune effectors into functional intragraft tertiary lymphoid tissue, a site where breakdown of B-cell tolerance may occur. To test this, we performed a comprehensive analysis of 26 chronically rejected kidney grafts. Antibodies were screened by indirect immunofluorescence on HEp2 cells, a procedure that detects antibodies to intracellular antigens, and monkey kidney sections, which detects kidney tissue autoantigens. The incidence of anti-HEp2 autoantibodies was significantly higher in graft explant culture supernatants than in patient sera. Reactivity against monkey kidney sections was detected in almost half of culture supernatants with anti-HEp2 autoantibodies. A local enrichment in T helper 17 and B-cell-activating factor (CD257) correlated with intragraft production of anti-HEp2 antibodies. A decrease in Tregs and a symmetric increase of activated OX40 (CD134)-expressing CD4+ T cells were found in grafts in which anti-kidney autoantibodies were produced. Thus, a stepwise breakdown of B-cell tolerance occurs within the graft during chronic rejection. Hence, the intragraft microenvironment interferes with peripheral deletion of autoreactive immature B cells that, in turn, produce antibodies against intracellular autoantigens. When intragraft immune regulation is insufficient, spreading of the local response against kidney autoantigens is favored

Multiparametric radiobiological assays show that variation of X-ray energy strongly impacts relative biological effectiveness: comparison between 220 kV and 4 MV

International audienceBased on classic clonogenic assay, it is accepted by the scientific community that, whatever the energy, the relative biological effectiveness of X-rays is equal to 1. However, although X-ray beams are widely used in diagnosis, interventional medicine and radiotherapy, comparisons of their energies are scarce. We therefore assessed in vitro the effects of low- and high-energy X-rays using Human umbilical vein endothelial cells (HUVECs) by performing clonogenic assay, measuring viability/mortality, counting γ-H2AX foci, studying cell proliferation and cellular senescence by flow cytometry and by performing gene analysis on custom arrays. Taken together, excepted for γ-H2AX foci counts, these experiments systematically show more adverse effects of high energy X-rays, while the relative biological effectiveness of photons is around 1, whatever the quality of the X-ray beam. These results strongly suggest that multiparametric analysis should be considered in support of clonogenic assay

Comparative genomics reveals new functional insights in uncultured MAST species

Heterotrophic lineages of stramenopiles exhibit enormous diversity in morphology, lifestyle, and habitat. Among them, the marine stramenopiles (MASTs) represent numerous independent lineages that are only known from environmental sequences retrieved from marine samples. The core energy metabolism characterizing these unicellular eukaryotes is poorly understood. Here, we used single-cell genomics to retrieve, annotate, and compare the genomes of 15 MAST species, obtained by coassembling sequences from 140 individual cells sampled from the marine surface plankton. Functional annotations from their gene repertoires are compatible with all of them being phagocytotic. The unique presence of rhodopsin genes in MAST species, together with their widespread expression in oceanic waters, supports the idea that MASTs may be capable of using sunlight to thrive in the photic ocean. Additional subsets of genes used in phagocytosis, such as proton pumps for vacuole acidification and peptidases for prey digestion, did not reveal particular trends in MAST genomes as compared with nonphagocytotic stramenopiles, except a larger presence and diversity of V-PPase genes. Our analysis reflects the complexity of phagocytosis machinery in microbial eukaryotes, which contrasts with the well-defined set of genes for photosynthesis. These new genomic data provide the essential framework to study ecophysiology of uncultured species and to gain better understanding of the function of rhodopsins and related carotenoids in stramenopiles

Rationale and protocol for the efficacy, safety and tolerability of nangibotide in patients with septic shock (ASTONISH) phase IIb randomised controlled trial.

INTRODUCTION: Septic shock is the subgroup of patients with sepsis, which presents as vasopressor dependence, an elevated blood lactate concentration and is associated with a mortality of at least 30%. Expression of the triggering receptor expressed on myeloid cells 1 (TREM-1) pathway, measured using a serum biomarker of pathway activation (soluble TREM-1, sTREM-1) has been associated with outcome in septic shock. Preclinical and early phase patient data suggest that therapeutic modulation of this pathway may improve survival. METHODS AND ANALYSIS: Efficacy, Safety and Tolerability of Nangibotide in Patients with Septic Shock is a phase IIb randomised controlled trial that will take place in up to 50 centres in seven countries and recruit 450 patients with septic shock to receive either placebo or one of two doses of nangibotide, a novel regulator of the TREM-1 pathway. The primary outcome will be the impact of nangibotide therapy on the change in Sequential Organ Failure Assessment score from a baseline determined before initiation of study drug therapy. This will be assessed first in the patients with an elevated sTREM-1 level and then in the study population as a whole. In addition to safety, secondary outcomes of the study will include efficacy of nangibotide in relation to sTREM-1 levels in terms of organ function, mortality and long-term morbidity. This study will also facilitate the development of a novel platform for the measurement of sTREM-1 at the point of care. ETHICS AND DISSEMINATION: The study has been approved by the responsible ethics committees/institutional review boards in all study countries: Belgium: Universitair Ziekenhuis Antwerpen, France: CPP Ile de France II, Denmark: Region Hovedstaden, Spain: ethics committee from Valld'Hebron Hospital, Barcelona, Finland: Tukija, Ireland: St. James' Hospital (SJH) / Tallaght University Hospital (TUH) Joint Research Ethics Committee, USA: Lifespan, Providence TRIAL REGISTRATION NUMBERS: EudraCT Number: 2018-004827-36 and NCT04055909

Can we identify the Mexican hairless dog in the archaeological record? Morphological and genetic insights from Tizayuca, Basin of Mexico

The Mexican Hairless dog, or Xoloitzcuintle, is a breed characterised by a sparse hair coat and a severe oligodontia. This phenotype is a consequence of Canine Ectodermal Dysplasia (CED) caused by a mutation on the FoxI3 autosomal gene. First accounts of hairless dogs in Mexico are dated to the 16th century CE, according to the historical record, but pre-Hispanic dog skeletons presenting missing and abnormally shaped teeth have been interpreted as earlier evidence of hairless dogs. However, several questions remain unanswered regarding the timing of apparition of this phenotype and its relationship with modern hairless breeds. In this paper, we review the morphological characteristics of potential hairless dogs and we apply ancient mitochondrial DNA analyses along with radiocarbon dating to eight archaeological dog mandibles from Tizayuca, Basin of Mexico, presenting anomalies that could be attributed to a CED. The archaeological dogs were dated between 1620 and 370 years BP. Among these eight individuals, we identify four different mitochondrial haplotypes including two novel haplotypes. The dogs from the Basin of Mexico display a very high genetic diversity and continuity from the Classic to the Postclassic. However, our attempt at amplifying the FoxI3 mutation was unsuccessful. Finally, we show that some haplotypes are present in both archaeological dogs and modern hairless breeds, perhaps reflecting their maternal ancestry