105 research outputs found
Fast Luminosity Monitoring using Diamond Sensors for the Super Flavor Factory SuperKEKB
ISBN 978-3-95450-132-8 - http://accelconf.web.cern.ch/AccelConf/IPAC2014/papers/thpme090.pdfInternational audienceSuper luminous flavor factories, as SuperKEKB in Japan, aim to achieve very high luminosity thanks to a newly employed concept, the nano-beam scheme, where ultra-low emittance beams collide at very large crossing angle. Luminosity optimisation and dynamic imperfections require fast luminosity measurements. The aimed precision, 10â3 in 10 ms, can be achieved thanks to the very large cross-section of the radiative Bhabha process at zero-photon scattering angle. As a result of huge particle fluxes, diamond sensors are chosen to be placed just outside the beam-pipe, downstream of the interaction point, at locations with event rates consistent with the aimed precision and small enough contamination by backgrounds from single-beam particle losses. We will present the results concerning the investigation of the optimal positioning of our diamond sensors, taking into account the rate of Bhabha particles as well as their interactions with the beam pipe material
An indole alkaloid from Strychnos erichsonii
Le premier alcaloïde indolique de type vobasine rencontré dans les #Loganiaceae a été isolé des écorces de #Strychnos erichsonii, récoltées en Guyane Française. Sa structure confirmée par cristallographie Rx. (Résumé d'auteur
Diagnosis of focal liver lesions from ultrasound using deep learning
PURPOSE: The purpose of this study was to create an algorithm that simultaneously detects and characterizes (benign vs. malignant) focal liver lesion (FLL) using deep learning.
MATERIALS AND METHODS: We trained our algorithm on a dataset proposed during a data challenge organized at the 2018 Journées Francophones de Radiologie. The dataset was composed of 367 two-dimensional ultrasound images from 367 individual livers, captured at various institutions. The algorithm was guided using an attention mechanism with annotations made by a radiologist. The algorithm was then tested on a new data set from 177 patients.
RESULTS: The models reached mean ROC-AUC scores of 0.935 for FLL detection and 0.916 for FLL characterization over three shuffled three-fold cross-validations performed with the training data. On the new dataset of 177 patients, our models reached a weighted mean ROC-AUC scores of 0.891 for seven different tasks.
CONCLUSION: This study that uses a supervised-attention mechanism focused on FLL detection and characterization from liver ultrasound images. This method could prove to be highly relevant for medical imaging once validated on a larger independent cohort
Organocatalysis for depolymerisation
Polymeric materials have been accumulating in the environment for decades as a result of the linear way of consuming plastics. Unfortunately, the current approaches followed to treat such a large amount of plastic waste, mainly involving physical recycling or pyrolysis, are not efficient enough. Recently, chemical degradation has emerged as a long-term strategy towards reaching completely sustainable cycles where plastics are polymerised, depolymerised, and then re-polymerised with minimal changes in their quantity or final properties. Organocatalysts, which are promising âgreenâ substitutes for traditional organometallic complexes, are able to catalyse depolymerisation reactions yielding highly pure small molecules that are adequate for subsequent polymerisations or other uses. Moreover, by varying several reaction parameters (e.g. solvent, temperature, concentration, co-catalyst, etc.), the depolymerisation products can be tuned in innumerable possibilities, which further evidences the versatility of depolymerisation. In this review, we highlight the recent advances made by applying organocatalysts, such as organic bases, organic acids, and ionic compounds, to chemically degrade the most commonly used commercial polymers. Indeed, organocatalysis is envisaged as a promising tool to reach a circular and environmentally friendly plastic economy.Postprint (published version
High flux polarized gamma rays production: first measurements with a four-mirror cavity at the ATF
The next generation of e+/e- colliders will require a very intense flux of
gamma rays to allow high current polarized positrons to be produced. This can
be achieved by converting polarized high energy photons in polarized pairs into
a target. In that context, an optical system consisting of a laser and a
four-mirror passive Fabry-Perot cavity has recently been installed at the
Accelerator Test Facility (ATF) at KEK to produce a high flux of polarized
gamma rays by inverse Compton scattering. In this contribution, we describe the
experimental system and present preliminary results. An ultra-stable
four-mirror non planar geometry has been implemented to ensure the polarization
of the gamma rays produced. A fiber amplifier is used to inject about 10W in
the high finesse cavity with a gain of 1000. A digital feedback system is used
to keep the cavity at the length required for the optimal power enhancement.
Preliminary measurements show that a flux of about /s with
an average energy of about 24 MeV was generated. Several upgrades currently in
progress are also described
Non-planar four-mirror optical cavity for high intensity gamma ray flux production by pulsed laser beam Compton scattering off GeV-electrons
As part of the R&D toward the production of high flux of polarised Gamma-rays
we have designed and built a non-planar four-mirror optical cavity with a high
finesse and operated it at a particle accelerator. We report on the main
challenges of such cavity, such as the design of a suitable laser based on
fiber technology, the mechanical difficulties of having a high tunability and a
high mechanical stability in an accelerator environment and the active
stabilization of such cavity by implementing a double feedback loop in a FPGA
Joint EANM/SIOPE/RAPNO practice guidelines/SNMMI procedure standards for imaging of paediatric gliomas using PET with radiolabelled amino acids and [ÂčâžF]FDG: version 1.0
Positron emission tomography (PET) has been widely used in paediatric oncology. 2-Deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) is the most commonly used radiopharmaceutical for PET imaging. For oncological brain imaging, different amino acid PET radiopharmaceuticals have been introduced in the last years. The purpose of this document is to provide imaging specialists and clinicians guidelines for indication, acquisition, and interpretation of [18F]FDG and radiolabelled amino acid PET in paediatric patients affected by brain gliomas. There is no high level of evidence for all recommendations suggested in this paper. These recommendations represent instead the consensus opinion of experienced leaders in the field. Further studies are needed to reach evidence-based recommendations for the applications of [18F]FDG and radiolabelled amino acid PET in paediatric neuro-oncology. These recommendations are not intended to be a substitute for national and international legal or regulatory provisions and should be considered in the context of good practice in nuclear medicine. The present guidelines/standards were developed collaboratively by the EANM and SNMMI with the European Society for Paediatric Oncology (SIOPE) Brain Tumour Group and the Response Assessment in Paediatric Neuro-Oncology (RAPNO) working group. They summarize also the views of the Neuroimaging and Oncology and Theranostics Committees of the EANM and reflect recommendations for which the EANM and other societies cannot be held responsible
Production of gamma rays by pulsed laser beam Compton scattering off GeV-electrons using a non-planar four-mirror optical cavity
As part of the positron source R&D for future colliders and Compton
based compact light sources, a high finesse non-planar four-mirror Fabry-Perot
cavity has recently been installed at the ATF (KEK, Tsukuba, Japan). The first
measurements of the gamma ray flux produced with a such cavity using a pulsed
laser is presented here. We demonstrate the production of a flux of 2.7
0.2 gamma rays per bunch crossing ( gammas per second) during
the commissioning
CC9 Livestock-Associated Staphylococcus aureus Emerges in Bloodstream Infections in French Patients Unconnected With Animal Farming
We report 4 bloodstream infections associated with CC9 agr type II Staphylococcus aureus in individuals without animal exposure. We demonstrate, by microarray analysis, the presence of egc cluster, fnbA, cap operon, lukS, set2, set12, splE, splD, sak, epiD, and can, genomic features associated with a high virulence potential in human
The ThomX project status
Work supported by the French Agence Nationale de la recherche as part of the program EQUIPEX under reference ANR-10-EQPX-51, the Ile de France region, CNRS-IN2P3 and Université Paris Sud XI - http://accelconf.web.cern.ch/AccelConf/IPAC2014/papers/wepro052.pdfA collaboration of seven research institutes and an industry has been set up for the ThomX project, a compact Compton Backscattering Source (CBS) based in Orsay - France. After a period of study and definition of the machine performance, a full description of all the systems has been provided. The infrastructure work has been started and the main systems are in the call for tender phase. In this paper we will illustrate the definitive machine parameters and components characteristics. We will also update the results of the different technical and experimental activities on optical resonators, RF power supplies and on the electron gun
- âŠ