Scintillation of Sol-Gel derived Lutetium orthophosphate doped with rare earth ions.

In this paper, the synthesis, the characterization and the scintillation properties of LuPO4 doped, with several concentrations of Ce3+, Eu3+ and Tb3+ ions, are presented. These materials have been synthesized by sol-gel process. The purity of powders has been verified by X-Ray diffraction and the results confirm the xenotime structure of all the materials. A thermogravimetric analysis allows the obtention of informations on the crystallisation of LuPO4 and the study of its evolution from the amorphous to crystalline form. The morphology of the powders has been studied by Scanning Electron Microscopy and shows that the powders are constituted of small particles with narrow size distribution. Optical properties have been studied in order to determine the scintillation performances of these materials. The optima are obtained for Ce3+, Eu3+ and Tb3+ concentration of respectively 0.1%, 10% and 5% with high scintillation yields. This study thus confirms the potentialities of these materials as scintillators

Concentration effect on the scintillation properties of Sol-Gel derived LuBO3 doped with Eu3+ and Tb3+.

International audienceLu1-xEuxBO3 and Lu1-xTbxBO3 powders have been prepared by a sol-gel process with 0 < x < 0.15 for Eu3+ and 0 < x < 0.05 for Tb3+. The purity of powders has been verified by X-Ray diffraction and the results confirm that all the materials have the vaterite type even if the calcination has been performed at 800°C. Furthermore, the solid solution for LuBO3 vaterite is observed up to x=0.15 and x=0.05 for europium and terbium ions respectively. So doping with Eu3+ or Tb3+ ions does not affect the structure. These materials have also been analyzed by Fourier Transform Infra Red Spectroscopy. The morphology of the powders has been studied by Scanning Electron Microscopy and shows a very nice morphology with small spherical particles with narrow size distribution. Optical properties have then been studied to confirm the effective substitution of Eu3+ or Tb3+ for Lu3+ ions and to determine the materials scintillation performances. The optima, in term of scintillation yield, are obtained for Eu3+ and Tb3+ concentration of x=0.05 in both cases. The afterglows have also been measured and confirm the potentiality of these materials as scintillators

Characterization and Scintillation properties of Sol-Gel derived Lu2SiO5:Ln3+ (Ln = Ce, Eu, Tb) powders

International audienceIn this paper, we report the synthesis, the characterization and the scintillation properties of sol-gel derived Lu2SiO5 (LSO) powders. Ce3+, Eu3+ and Tb3+ doped LSO powders have been synthesized by an original sol-gel process. The purity of the materials has been checked by X-Ray diffraction, confirming the elaboration of monophasic powders even for doped samples. Finally, the scintillation properties of the rare earth doped materials have been studied, the substitution of Ln3+ (Ln: Ce, Eu or Tb) for Lu3+ is confirmed, the scintillation yields have been calculated and the afterglow have also been measured, confirming the potentiality of the sol-gel derived LSO

An in silico approach combined with in vivo experiments enables the identification of a new protein whose overexpression can compensate for specific respiratory defects in Saccharomyces cerevisiae

<p>Abstract</p> <p>Background</p> <p>The mitochondrial inner membrane contains five large complexes that are essential for oxidative phosphorylation. Although the structure and the catalytic mechanisms of the respiratory complexes have been progressively established, their biogenesis is far from being fully understood. Very few complex III assembly factors have been identified so far. It is probable that more factors are needed for the assembly of a functional complex, but that the genetic approaches used to date have not been able to identify them. We have developed a systems biology approach to identify new factors controlling complex III biogenesis.</p> <p>Results</p> <p>We collected all the physical protein-protein interactions (PPI) involving the core subunits, the supernumerary subunits and the assembly factors of complex III and used Cytoscape 2.6.3 and its plugins to construct a network. It was then divided into overlapping and highly interconnected sub-graphs with clusterONE. One sub-graph contained the core and the supernumerary subunits of complex III, it also contained some subunits of complex IV and proteins participating in the assembly of complex IV. This sub-graph was then split with another algorithm into two sub-graphs. The subtraction of these two sub-graphs from the previous sub-graph allowed us to identify a protein of unknown function Usb1p/Ylr132p that interacts with the complex III subunits Qcr2p and Cor1p. We then used genetic and cell biology approaches to investigate the function of Usb1p. Preliminary results indicated that Usb1p is an essential protein with a dual localization in the nucleus and in the mitochondria, and that the over-expression of this protein can compensate for defects in the biogenesis of the respiratory complexes.</p> <p>Conclusions</p> <p>Our systems biology approach has highlighted the multiple associations between subunits and assembly factors of complexes III and IV during their biogenesis. In addition, this approach has allowed the identification of a new factor, Usb1p, involved in the biogenesis of respiratory complexes, which could not have been found using classical genetic screens looking for respiratory deficient mutants. Thus, this systems biology approach appears to be a fruitful new way to study the biogenesis of mitochondrial multi-subunit complexes.</p

Observational study of adherence to European clinical practice guidelines for the management of acute coronary syndrome in revascularized versus non-revascularized patients – the CONNECT Study

SummaryBackgroundThe CONNECT study compared clinician adherence to guideline-recommended secondary prevention therapies prescribed at discharge for patients hospitalized for acute coronary syndrome (ACS) in those managed initially with percutaneous coronary intervention (PCI; revascularized) and those who did not undergo revascularization.MethodsPatients aged greater than or equal to 18 years, hospitalized for a documented ST-segment elevation or non-ST-segment elevation ACS, were enrolled consecutively over 1 month at 238 sites in France.ResultsCompared with revascularized patients (n=870), non-revascularized patients (n=706) were significantly older, and a greater proportion were women, had high-blood pressure, type-2 diabetes or a history of atherothrombotic or cardiac disease, but a smaller proportion had a history of coronary angioplasty. On discharge, non-revascularized patients were prescribed beta-blockers, aspirin, statins, angiotensin-converting enzyme inhibitors or adenosine diphosphate receptor antagonists less frequently than revascularized patients. An adherence score greater than or equal to 80% (at least four of the five recommended agents prescribed at discharge) was found in 96.7% of revascularized patients and 74.4% of non-revascularized patients (P<0.001).ConclusionsDespite a similar or even higher level of cardiovascular risk, non-revascularized ACS patients were prescribed guideline-recommended secondary prevention therapy less frequently than revascularized patients

Combining Cell-Free Protein Synthesis and NMR Into a Tool to Study Capsid Assembly Modulation

International audienceModulation of capsid assembly by small molecules has become a central concept in the fight against viral infection. Proper capsid assembly is crucial to form the high molecular weight structures that protect the viral genome and that, often in concert with the envelope, allow for cell entry and fusion. Atomic details underlying assembly modulation are generally studied using preassembled protein complexes, while the activity of assembly modulators during assembly remains largely open and poorly understood, as necessary tools are lacking. We here use the full-length hepatitis B virus (HBV) capsid protein (Cp183) as a model to present a combination of cell-free protein synthesis and solid-state NMR as an approach which shall open the possibility to produce and analyze the formation of higher-order complexes directly on exit from the ribosome. We demonstrate that assembled capsids can be synthesized in amounts sufficient for structural studies, and show that addition of assembly modulators to the cell-free reaction produces objects similar to those obtained by addition of the compounds to preformed Cp183 capsids. These results establish the cell-free system as a tool for the study of capsid assembly modulation directly after synthesis by the ribosome, and they open the perspective of assessing the impact of natural or synthetic compounds, or even enzymes that perform post-translational modifications, on capsids structures

YAG nano-light sources with high Ce concentration

We investigate the luminescence properties of 10 nm YAG nanoparticles doped with Ce ions at 0.2%, 4% and 13% that are designed as active probes for Scanning Near field Optical Microscopy. They are produced by a physical method without any subsequent treatment, which is imposed by the desired application. The structural analysis reveals the amorphous nature of the particles, which we relate to some compositional defect as indicated by the elemental analysis. The optimum emission is obtained with a doping level of 4%. The emission of the YAG nanoparticles doped at 0.2% is strongly perturbed by the crystalline disorder whereas the 13% doped particles hardly exhibit any luminescence. In the latter case, the presence of Ce4+ ions is confirmed, indicating that the Ce concentration is too high to be incorporated efficiently in YAG nanoparticles in the trivalent state. By a unique procedure combining cathodoluminescence and Rutherford backscattering spectrometry, we demonstrate that the enhancement of the particles luminescence yield is not proportional to the doping concentration, the emission enhancement being larger than the Ce concentration increase. Time-resolved photoluminescence reveals the presence of quenching centres likely related to the crystalline disorder as well as the presence of two distinct Ce ions populations. Eventually, nano-cathodoluminescence indicates that the emission and therefore the distribution of the doping Ce ions and of the defects are homogeneous

Daily allergy burden and heart rate characteristics in adults with allergic rhinitis based on a wearable telemonitoring system

Background: Allergic rhinitis includes a certain degree of autonomic imbalance. However, no information is available on how daily changes in allergy burden affect autonomic imbalance. We aimed to estimate associations between daily allergy burden (allergy symptoms and mood) and daily heart rate characteristics (resting heart rate and sample entropy, both biomarkers of autonomic balance) of adults with allergic rhinitis, based on real-world measurements with a wearable telemonitoring system. Methods: Adults with a tree pollen allergy used a smartphone application to self-report daily allergy symptoms (score 0–44) and mood (score 0–4), and a Mio Alpha 2 wristwatch to collect heart rate characteristics during two pollen seasons of hazel, alder and birch in Belgium. Associations between daily allergy burden and heart rate characteristics were estimated using linear mixed effects distributed lag models with a random intercept for individuals and adjusted for potential confounders. Results: Analyses included 2497 participant-days of 72 participants. A one-point increase in allergy symptom score was associated with an increase in next-day resting heart rate of 0.08 (95% CI: 0.02–0.15) beats per minute. A one-point increase in mood score was associated with an increase in same-day sample entropy of 0.80 (95% CI: 0.34–1.26) × 10−2. No associations were found between allergy symptoms and heart rate sample entropy, nor between mood and resting heart rate. Conclusion: Daily repeated measurements with a wearable telemonitoring system revealed that the daily allergy burden of adults with allergic rhinitis has systemic effects beyond merely the respiratory system.</p