220 research outputs found

    The CERN PS East Area in the LHC Era

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    Experiments planned at the CERN Large Hadron Collider (LHC) will require a well-equipped test area with low momentum (<15 Gev/c) secondary particle beams. These beams will be used to test some of the LHC detectors components (ALICE, ATLAS, CMS, LHCb). In addition another recently approved experiment (DIRAC) will be installed in the PS East Area. This experiment will require a primary proton beam of 24 GeV/c to test QCD predictions. In this context, the EHNL project (East Hall New Look) has been launched. The major modifications include (i) an extension of the present area with a primary 24 GeV/c beam line, (ii) a new secondary beam line lay-out with test areas at 3.5, 7, 10 and 15 GeV/c, (iii) an additional irradiation area, (iv) an improved facility for beam sharing between the various users. This paper describes the scope of the project, its new features, the planned facilities and its installation schedul

    Fast extracted proton beams at low energies in the CPS east experimental area

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    To provide beams with characteristics required by the Energy Amplifier Test, the CERN PS had to deliver new beams, of low kinetic energy (0.6 - 2.7 GeV), low intensity (0.5-5„109p) and short duration (<500 ns) via the existing slow extraction channel, the transfer line currently used for 24 GeV/c beams and a slightly modified secondary line. These beams were delivered without impairing other CPS operations and, despite large operational differences, the other three East area beam lines could alternatively be supplied with slow extracted beam, for half week periods, thanks to the short setting-up time of a few hours. This paper describes how such beams were produced: by (i) acceleration or deceleration of the injected beam in the CPS, depending on the requested energy, (ii) fast extraction using the usual slow extraction channel, (iii) careful optics adjustments and reduction of multiple scattering in the transfer line. The range of beam characteristics achieved, as well as the limitations encountered are also reported

    Multisensory data fusion for localisation in mobile robotics

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    Mobile robotics is an essential application field for multisensor fusion . This paper presents some works performed in three Frenc h laboratories concerning the localisation of mobile robots . The proposed methods and algorithms combine the relative localisatio n obtained from vehicle referenced sensors (odometers and accelerometers) and measurements from world characteristics (punctua l beacons and landmarks) such as distances or angles . The main discussed formalism is Kalman filtering . Anyway, the method is shown to be adaptable to the use of bounded erro r estimation algorithms . This last technique has been found to be well suited to the treatment of blind zones in (restricted) visio n problems . Sensor fusion yields at the same time an estimation of the robot configuration (position, orientation, . . .) together wit h the uncertainty of this estimation . A generalisation of localisation algorithms in a partially known environment is further discussed . In this case, the position of poorly known beacons is updated in the same time the localisation of the robot is obtained from accurately known references . Additionally, an intelligent management of world referenced measurements is used to select the most useful data in order to limit th e computational burden of the localisation and to speed up the real time execution of the algorithms without significant degradatio n of estimator performances . The different solutions have been validated and are illustrated by simulations and real experiments .La robotique mobile est un champ d'application privilĂ©giĂ© de la fusion de donnĂ©es multisensorielles. Cet article est une synthĂšse de travaux effectuĂ©s dans trois laboratoires sur la localisation de vĂ©hicules mobiles. AprĂšs avoir dĂ©fini le problĂšme, nous prĂ©sentons les algorithmes proposĂ©s combinant la localisation relative - obtenue par exploitation des donnĂ©es fournies par diffĂ©rents capteurs proprioceptifs (odomĂštre et centrale Ă  inertie) - avec un recalage absolu par rapport Ă  des balises ponctuelles ou des segments de droite - les mesures Ă©tant des distances et/ou des angles. Le formalisme retenu est principalement celui du filtrage de Kalman mais, de maniĂšre similaire, la localisation des vĂ©hicules peut ĂȘtre obtenue en mettant en oeuvre un algorithme d'estimation Ă  erreur bornĂ©e. Cette derniĂšre technique est bien adaptĂ©e pour la gestion de donnĂ©es manquantes dans des angles morts, point qui est Ă©galement abordĂ©. La fusion de donnĂ©es fournit non seulement une estimation de la configuration du robot (position, orientation,...) mais Ă©galement l'incertitude avec laquelle cette grandeur est connue. Une gĂ©nĂ©ralisation des algorithmes dans un environnement qui n'est que partiellement connu est Ă©galement prĂ©sentĂ©e : la position des repĂšres mal connus est recalĂ©e et la localisation du robot est effectuĂ©e avec des repĂšres bien connus. Une gestion intelligente des donnĂ©es extĂ©roceptives permet de sĂ©lectionner ou de prĂ©voir celles qui sont les plus pertinentes, limitant ainsi les traitements et les calculs sans pour autant dĂ©grader de façon significative les performances de l'estimateur de la configuration du vĂ©hicule. Les diffĂ©rentes solutions proposĂ©es ont Ă©tĂ© validĂ©es en simulation et partiellement testĂ©es sur site rĂ©el avec diffĂ©rents robots et capteurs

    An Empirical Process Central Limit Theorem for Multidimensional Dependent Data

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    Let (Un(t))t∈Rd(U_n(t))_{t\in\R^d} be the empirical process associated to an Rd\R^d-valued stationary process (Xi)i≄0(X_i)_{i\ge 0}. We give general conditions, which only involve processes (f(Xi))i≄0(f(X_i))_{i\ge 0} for a restricted class of functions ff, under which weak convergence of (Un(t))t∈Rd(U_n(t))_{t\in\R^d} can be proved. This is particularly useful when dealing with data arising from dynamical systems or functional of Markov chains. This result improves those of [DDV09] and [DD11], where the technique was first introduced, and provides new applications.Comment: to appear in Journal of Theoretical Probabilit

    Comparison of large-angle production of charged pions with incident protons on cylindrical long and short targets

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    The HARP collaboration has presented measurements of the double-differential pi+/pi- production cross-section in the range of momentum 100 MeV/c <= p 800 MeV/c and angle 0.35 rad <= theta <= 2.15 rad with proton beams hitting thin nuclear targets. In many applications the extrapolation to long targets is necessary. In this paper the analysis of data taken with long (one interaction length) solid cylindrical targets made of carbon, tantalum and lead is presented. The data were taken with the large acceptance HARP detector in the T9 beam line of the CERN PS. The secondary pions were produced by beams of protons with momenta 5 GeV/c, 8 GeV/c and 12 GeV/c. The tracking and identification of the produced particles were performed using a small-radius cylindrical time projection chamber (TPC) placed inside a solenoidal magnet. Incident protons were identified by an elaborate system of beam detectors. Results are obtained for the double-differential yields per target nucleon d2 sigma / dp dtheta. The measurements are compared with predictions of the MARS and GEANT4 Monte Carlo simulations.Comment: 43 pages, 20 figure

    Feasibility Study of a Neutron Time Of Flight Facility at the CERN-PS

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    This report summarises the feasibility study of a neutron time-of-flight facility at the CERN-PS as described in Refs. [1] and [2]. The idea is to extract at 24 GeV/cproton bunches (r.m.s. length ~7 ns) on to a target. The neutrons produced by spallation are directed to an experimental area located 230 m downstream throughout a vacuum pipe (diameter ~80 cm) making use of the existing TT2A tunnel about 7 m below the ISR tunne

    Exosomes released by EBV-infected nasopharyngeal carcinoma cells convey the viral Latent Membrane Protein 1 and the immunomodulatory protein galectin 9

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    BACKGROUND: Nasopharyngeal carcinomas (NPC) are consistently associated with the Epstein-Barr virus (EBV). Their malignant epithelial cells contain the viral genome and express several antigenic viral proteins. However, the mechanisms of immune escape in NPCs are still poorly understood. EBV-transformed B-cells have been reported to release exosomes carrying the EBV-encoded latent membrane protein 1 (LMP1) which has T-cell inhibitory activity. Although this report suggested that NPC cells could also produce exosomes carrying immunosuppressive proteins, this hypothesis has remained so far untested. METHODS: Malignant epithelial cells derived from NPC xenografts – LMP1-positive (C15) or negative (C17) – were used to prepare conditioned culture medium. Various microparticles and vesicles released in the culture medium were collected and fractionated by differential centrifugation. Exosomes collected in the last centrifugation step were further purified by immunomagnetic capture on beads carrying antibody directed to HLA class II molecules. Purified exosomes were visualized by electron microscopy and analysed by western blotting. The T-cell inhibitory activities of recombinant LMP1 and galectin 9 were assessed on peripheral blood mononuclear cells activated by CD3/CD28 cross-linking. RESULTS: HLA-class II-positive exosomes purified from C15 and C17 cell supernatants were containing either LMP1 and galectin 9 (C15) or galectin 9 only (C17). Recombinant LMP1 induced a strong inhibition of T-cell proliferation (IC50 = 0.17 nM). In contrast recombinant galectin 9 had a weaker inhibitory effect (IC50 = 46 nM) with no synergy with LMP1. CONCLUSION: This study provides the proof of concept that NPC cells can release HLA class-II positive exosomes containing galectin 9 and/or LMP1. It confirms that the LMP1 molecule has intrinsic T-cell inhibitory activity. These findings will encourage investigations of tumor exosomes in the blood of NPC patients and assessment of their effects on various types of target cells

    CTF3 Design Report: Preliminary Phase

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    The design of CLIC is based on a two-beam scheme, where the short pulses of high power 30 GHz RF are extracted from a drive beam running parallel to the main beam. The 3rd generation CLIC Test Facility (CTF3) will demonstrate the generation of the drive beam with the appropriate time structure, the extraction of 30 GHz RF power from this beam, as well as acceleration of a probe beam with 30 GHz RF cavities. The project makes maximum use of existing equipment and infrastructure of the LPI complex, which became available after the closure of LEP. In the first stage of the project, the "Preliminary Phase", the existing LIL linac and the EPA ring, both modified to suit the new requirements, are used to investigate the technique of frequency multiplication by means of interleaving bunches from subsequent trains. This report describes the design of this phase

    Combined strategy based on pre-activated analogs of oxazaphosphorines for increased therapeutic index and immune modulation

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    Oxazaphosphorines (Oxaza) represented by cyclophosphamide (CPA) and ifosfamide (IFO) are still the corner stone of several polychemotherapy protocols as they are widely indicated in the treatment of numerous cancer from soft tissue sarcomas to lymphomas and immune-related diseases. However, Oxaza are prodrugs requiring cytochrome (CYP) P450 bioactivation responsible of limiting adverse effects. In the case of IFO, bioactivation leads to a low release of 4-OH-IFO (10%), which generates the active nitrogen mustard displaying DNA cross-links. Associated toxicities of IFO due to acrolein, (urotoxicity) and to chloroacetaldehyde (neuro and nephrotoxicity) have been described. Thus, increasing IFO therapeutic index could be of major interest. To circumvent these toxicities, our team has designed new pre-activated IFO analogs to avoid CYP bioactivation (Skarbek et al J Med Chem 2015). Among these analogues some have the ability to self-assemble as nanoassemblies (NAs), the others can be encapsulated within nano-lipid capsules (NLCs). These new drug delivery systems (DDS) can take advantage of passive targeting, as stealthiness of these DDS can be provided by PEGylation by using Cholesterol-polyethylene glycol or the use of surfactant. These DDS can also be functionalized by appropriate monoclonal antibodies leading to multi stage DDS with active targeting properties. Regarding CPA, it has been shown and described in literature that low doses of CPA enhance the immunity by promoting differentiation of CD4âș cell toward Th1. As IFO is isomeric form of CPA, it was assumed that IFO could also have such properties. Studies on immunocompetent MCA205 mouse model, an immunogenic fibrosarcoma mouse model, demonstrate a dose-dependent immunomodulation of IFO towards a modulation of the secretion of IFNy, IL-17A and IL-6 cytokines. The ongoing experiments on mouse model depleted in CD4âș T cells and CD8âș T cells show the antitumor efficacy of IFO 150mg/kg on these immune cells in tumor regression. Both strategies could lead to the design of nano-immuno-conjugates (NICs) which could benefit of the immunomodulatory effects of X-Oxaza combined to their antiproliferative properties targeted through immune checkpoint antibodies. These new functionalized DDS may provide a useful strategy to give specificity to active drugs used for many years in clinical practice. Both DDS could be grafted with mAbs which could lead to a new family of DDS aiming to combine antiproliferative and immunomodulatory properties for a dual antitumoral action Citation Format: Julia Delahousse, Charles Skarbek, Valentine Gauthier, M Desbois, Emilie Roger, C. Pioche-Durieu, M. Rivard, D. DesmaĂ«le, T. Martens, E. LeCam, Jean-Pierre Benoit, P. Couvreur, Nathalie Chaput-Gras, Angelo Paci. Combined strategy based on pre-activated analogs of oxazaphosphorines for increased therapeutic index and immune modulation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2195. doi:10.1158/1538-7445.AM2017-219

    Inside-Out Regulation of ICAM-1 Dynamics in TNF-α-Activated Endothelium

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    Background: During transendothelial migration, leukocytes use adhesion molecules, such as ICAM-1, to adhere to the endothelium. ICAM-1 is a dynamic molecule that is localized in the apical membrane of the endothelium and clusters upon binding to leukocytes. However, not much is known about the regulation of ICAM-1 clustering and whether membrane dynamics are linked to the ability of ICAM-1 to cluster and bind leukocyte integrins. Therefore, we studied the dynamics of endothelial ICAM-1 under non-clustered and clustered conditions. Principal Findings: Detailed scanning electron and fluorescent microscopy showed that the apical surface of endothelial cells constitutively forms small filopodia-like protrusions that are positive for ICAM-1 and freely move within the lateral plane of the membrane. Clustering of ICAM-1, using anti-ICAM-1 antibody-coated beads, efficiently and rapidly recruits ICAM-1. Using fluorescence recovery after photo-bleaching (FRAP), we found that clustering increased the immobile fraction of ICAM-1, compared to non-clustered ICAM-1. This shift required the intracellular portion of ICAM-1. Moreover, biochemical assays showed that ICAM-1 clustering recruited beta-actin and filamin. Cytochalasin B, which interferes with actin polymerization, delayed the clustering of ICAM-1. In addition, we could show that cytochalasin B decreased the immobile fraction of clustered ICAM-1-GFP, but had no effect on non-clustered ICAM-1. Also, the motor protein myosin-II is recruited to ICAM-1 adhesion sites and its inhibition increased the immobile fraction of both non-clustered and clustered ICAM-1. Finally, blocking Rac1 activation, the formation of lipid rafts, myosin-II activity or actin polymerization, but not Src, reduced the adhesive function of ICAM-1, tested under physiological flow conditions. Conclusions: Together, these findings indicate that ICAM-1 clustering is regulated in an inside-out fashion through the actin cytoskeleton. Overall, these data indicate that signaling events within the endothelium are required for efficient ICAM-1-mediated leukocyte adhesio
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