The Winchcombe meteorite, a unique and pristine witness from the outer solar system.

Direct links between carbonaceous chondrites and their parent bodies in the solar system are rare. The Winchcombe meteorite is the most accurately recorded carbonaceous chondrite fall. Its pre-atmospheric orbit and cosmic-ray exposure age confirm that it arrived on Earth shortly after ejection from a primitive asteroid. Recovered only hours after falling, the composition of the Winchcombe meteorite is largely unmodified by the terrestrial environment. It contains abundant hydrated silicates formed during fluid-rock reactions, and carbon- and nitrogen-bearing organic matter including soluble protein amino acids. The near-pristine hydrogen isotopic composition of the Winchcombe meteorite is comparable to the terrestrial hydrosphere, providing further evidence that volatile-rich carbonaceous asteroids played an important role in the origin of Earth's water

The high-resolution map of Oxia Planum, Mars; the landing site of the ExoMars Rosalind Franklin rover mission

This 1:30,000 scale geological map describes Oxia Planum, Mars, the landing site for the ExoMars Rosalind Franklin rover mission. The map represents our current understanding of bedrock units and their relationships prior to Rosalind Franklin’s exploration of this location. The map details 15 bedrock units organised into 6 groups and 7 textural and surficial units. The bedrock units were identified using visible and near-infrared remote sensing datasets. The objectives of this map are (i) to identify where the most astrobiologically relevant rocks are likely to be found, (ii) to show where hypotheses about their geological context (within Oxia Planum and in the wider geological history of Mars) can be tested, (iii) to inform both the long-term (hundreds of metres to ∼1 km) and the short-term (tens of metres) activity planning for rover exploration, and (iv) to allow the samples analysed by the rover to be interpreted within their regional geological context

Lipid and apolipoprotein levels in an Australian community

Serum levels of total and high density lipoprotein (HDL) cholesterol and apolipoproteins A1 and B were measured in over 600 men and women aged 30-69 years who were selected at random from an Australian community. Total cholesterol and apolipoprotein A1 and B levels increased with age, with this effect being most pronounced for total cholesterol and apolipoprotein B in women. Body mass index and waist-to-hip ratio were positively correlated with apolipoprotein B and total cholesterol levels, and negatively correlated with apolipoprotein A1 and HDL cholesterol levels. All lipid and apolipoprotein A1 levels increased with the quantity of alcohol consumed. Affer adjusting for age, body mass index and smoking, the association with alcohol was strongest for apolipoprotein A1 and HDL cholesterol levels in men (P = 0.0001), and for apolipoprotein A1 levels in women (P = 0.01). Levels of apolipoprotein A1 and HDL cholesterol were lower, and of apolipoprotein B and total cholesterol were higher, in current cigarette smokers than non-smokers, with significant associations for apolipoprotein B (P = 0.004) and HDL cholesterol levels (P = 0.04) in men. In general, the associations between apolipoprotein A1 levels and the other variables were weaker than those for HDL cholesterol levels, whereas the associations with apolipoprotein B levels were stronger than those for total cholesterol levels (except for alcohol consumption). Thus, obesity, alcohol consumption and cigarette smoking should be considered when interpreting apolipoprotein levels

ExoFiT: ExoMars-Like Field Trials – a Mission Simulation.

International audienceHere, we focus on the ExoMars-Like Field Trial (ExoFiT), a series of realistic mission simulations based on the ESA ExoMars rover mission slated to be launched in 2020. The mission will carry a suite of instruments to carry out its mission objectives focused on geological and exobiological researc

Suboptimal Activation of Protease-activated Receptors Enhances α2β1 Integrin-mediated Platelet Adhesion to Collagen*

Thrombin and fibrillar collagen are potent activators of platelets at sites of vascular injury. Both agonists cause platelet shape change, granule secretion, and aggregation to form the primary hemostatic plug. Human platelets express two thrombin receptors, protease-activated receptors 1 and 4 (PAR1 and PAR4) and two collagen receptors, the α2β1 integrin (α2β1) and the glycoprotein VI (GPVI)/FcRγ chain complex. Although these receptors and their signaling mechanisms have been intensely studied, it is not known whether and how these receptors cooperate in the hemostatic function of platelets. This study examined cooperation between the thrombin and collagen receptors in platelet adhesion by utilizing a collagen-related peptide (α2-CRP) containing the α2β1-specific binding motif, GFOGER, in conjunction with PAR-activating peptides. We demonstrate that platelet adhesion to α2-CRP is substantially enhanced by suboptimal PAR activation (agonist concentrations that do not stimulate platelet aggregation) using the PAR4 agonist peptide and thrombin. The enhanced adhesion induced by suboptimal PAR4 activation was α2β1-dependent and GPVI/FcRγ-independent as revealed in experiments with α2β1- or FcRγ-deficient mouse platelets. We further show that suboptimal activation of other platelet Gq-linked G protein-coupled receptors (GPCRs) produces enhanced platelet adhesion to α2-CRP. The enhanced α2β1-mediated platelet adhesion is controlled by phospholipase C (PLC), but is not dependent on granule secretion, activation of αIIbβ3 integrin, or on phosphoinositol-3 kinase (PI3K) activity. In conclusion, we demonstrate a platelet priming mechanism initiated by suboptimal activation of PAR4 or other platelet Gq-linked GPCRs through a PLC-dependent signaling cascade that promotes enhanced α2β1 binding to collagens containing GFOGER sites