High pressure behavior of CsC8 graphite intercalation compound

International audienceThe high pressure phase diagram of CsC8 graphite intercalated compound has been investigated at ambient temperature up to 32 GPa. Combining X-ray and neutron diffraction, Raman and X- ray absorption spectroscopies, we report for the first time that CsC8, when pressurized, undergoes phase transitions around 2.0, 4.8 and 8 GPa. Possible candidate lattice structures and the transition mechanism involved are proposed. We show that the observed transitions involve the structural re- arrangement in the Cs sub-network while the distance between the graphitic layers is continuously reduced at least up to 8.9 GPa. Around 8 GPa, important modifications of signatures of the electronic structure measured by Raman and X-ray absorption spectroscopies evidence the onset of a new transition

Rochechouart 2017-Drilling Campaign: First Results

No abstract available

EPIdemiology of Surgery-Associated Acute Kidney Injury (EPIS-AKI) : Study protocol for a multicentre, observational trial

More than 300 million surgical procedures are performed each year. Acute kidney injury (AKI) is a common complication after major surgery and is associated with adverse short-term and long-term outcomes. However, there is a large variation in the incidence of reported AKI rates. The establishment of an accurate epidemiology of surgery-associated AKI is important for healthcare policy, quality initiatives, clinical trials, as well as for improving guidelines. The objective of the Epidemiology of Surgery-associated Acute Kidney Injury (EPIS-AKI) trial is to prospectively evaluate the epidemiology of AKI after major surgery using the latest Kidney Disease: Improving Global Outcomes (KDIGO) consensus definition of AKI. EPIS-AKI is an international prospective, observational, multicentre cohort study including 10 000 patients undergoing major surgery who are subsequently admitted to the ICU or a similar high dependency unit. The primary endpoint is the incidence of AKI within 72 hours after surgery according to the KDIGO criteria. Secondary endpoints include use of renal replacement therapy (RRT), mortality during ICU and hospital stay, length of ICU and hospital stay and major adverse kidney events (combined endpoint consisting of persistent renal dysfunction, RRT and mortality) at day 90. Further, we will evaluate preoperative and intraoperative risk factors affecting the incidence of postoperative AKI. In an add-on analysis, we will assess urinary biomarkers for early detection of AKI. EPIS-AKI has been approved by the leading Ethics Committee of the Medical Council North Rhine-Westphalia, of the Westphalian Wilhelms-University Münster and the corresponding Ethics Committee at each participating site. Results will be disseminated widely and published in peer-reviewed journals, presented at conferences and used to design further AKI-related trials. Trial registration number NCT04165369

Drying colloidal systems: laboratory models for a wide range of applications

The drying of complex fluids provides a powerful insight into phenomena that take place on time and length scales not normally accessible. An important feature of complex fluids, colloidal dispersions and polymer solutions is their high sensitivity to weak external actions. Thus, the drying of complex fluids involves a large number of physical and chemical processes. The scope of this review is the capacity to tune such systems to reproduce and explore specific properties in a physics laboratory. A wide variety of systems are presented, ranging from functional coatings, food science, cosmetology, medical diagnostics and forensics to geophysics and art

Une géométrie critique des lasers contenant des effets de lentille. II: Commentaire à « sur la longueur critique d'un laser » par G. Stephan

We give the result of an experiment which shows that the critical length, predicted in the frame of the ABCD matrix formalism, exists when the active medium fills the cavity. The critical length concept does not require the mean-field approximation hypothesis.Nous donnons le résultat d'une expérience qui montre que la géométrie critique, prévue par le formalisme de la matrice ABCD, existe lorsque le milieu remplit la cavité. Le concept de longueur critique n'exige pas l'hypothèse du champ moyen

A critical geometry for lasers with internal lenslike effects

We point out here an interesting property concerning Gaussian mode size evolution when a thin lens or induced lenslike effects are inserted in a laser cavity. When the distance d between mirrors of a half-symmetric Fabry-Perot with a lens at half-length is changed, the variations of the mode size at the curved mirror cancel for dc ≅ 4 R/5, and change sign when d ≧ dc (where R is the mirror curvature radius). This property explains simply opposite asymmetries observable on Lamb dips, saturated absorption peaks, and intracavity absorption spectroscopy resonances. The experimental verification is performed on the Lamb dip at 3.39 μm by diffracted light spectroscopy.Nous signalons une propriété intéressante concernant l'évolution de la taille d'un mode Gaussien lorsqu'une lentille mince ou une lentille induite répartie est insérée dans une cavité laser. Si on allonge une cavité Fabry-Perot plan concave contenant une lentille placée à mi-distance des miroirs, les variations de taille de mode sur le miroir concave s'annulent pour d c ≅ 4 R/5 et changent de signe pour d ≧ d c, R étant le rayon de courbure du miroir concave. Cette propriété explique simplement les dissymétries opposées observables sur le Lamb dip, les pics d'absorption saturée et les résonances de la spectroscopie d'absorption intracavité. La vérification expérimentale est faite sur le Lamb dip à 3,39 μm grâce à la spectroscopie du diffracté

Systemic administration of cationic phosphonolipids/DNA complexes and the relationship between formulation and lung transfection efficiency

International audiencePerformances of cationic lipid formulations for intravenous gene delivery to mouse lungs have been previously reported. We report in this study that cationic phosphonolipids, when appropriately formulated, can be good synthetic vectors for gene delivery to lung after intravenous administration. One of our reagents, GLB43, was capable of mediating a 500-fold higher expression in the lungs of mice than could be obtained with free pDNA alone (P=0.018). We demonstrate that the most important parameters for cationic phosphonolipid transfection activity after systemic administration are the chemical structure of the cationic phosphonolipid, the lipid to DNA charge ratio and the inclusion of co-lipid in the formulation. We report using a luciferase reporter gene that transfection activity in vivo 24 h after cationic phosphonolipid systemic administration could not be predicted from in vitro analysis. In contrast to in vitro studies, cationic phosphonolipids including the oleyl acyl chains (GLB43) were more effective than its analogue with the myristyl acyl chains (GLB73). Using pathological analysis of animal livers, we demonstrate that the toxicity level was correlated with the lipoplex formulation and the lipid to DNA ratio. Copyright (C) 2000 Elsevier Science B.V

Transgene expression kinetics after transfection with cationic phosphonolipids in hematopoietic non adherent cells

International audienceCationic lipids are considered to be capable of efficiently and safely mediating DNA transfer into cells, although expression is transient. A new family of cationic lipids, called phosphonolipids, has been developed, with the relationship between the hydrophobic domain of the lipid molecules and the significant enhancement of transduction efficiency in a non-adherent cell line characterised in the present study. The kinetics of transfection efficiency were also investigated. Our results demonstrate that the peak of the transient expression of these reporter genes mediated by cationic lipids occurred within 3 to 14 days, depending on the aliphatic chain length of the complex used and on its formulation in the presence or absence of DOPE. Furthermore, the kinetics of transgene expression were found to differ in adherent and non-adherent cells. These results were obtained using three different techniques: CPRG, luminescence, and FACS-gal, and were in agreement with electron microscopy studies. We thus hypothesized that the plasma membrane composition of cells could affect the efficiency of transfection with cationic lipids. Our results suggest that phosphonolipids constitute a promising class of compounds for gene transfer protocols, and that galenic optimization should improve and modify the transfection efficiency of these DNA-lipid complexes