6,528 research outputs found

    Review of Precision Determinations of the Accelerator Luminosity in LEP Experiments

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    The LEP collaborations ALEPH, DELPHI, L3 and OPAL were able to measure the accelerator luminosity with an experimental uncertainty smaller than 0.1%. Motivations, method, technological aspects and main difficulties of the measurements are reviewed

    Use of antifuse-FPGAs in the Track-Sorter-Master of the CMS Drift Tube Chambers

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    The front-end system of the Silicon Drift Detectors (SDDs) of the ALICE experiment is made of two ASICs. The first chip performs the preamplification, temporary analogue storage and analogue-to-digital conversion of the detector signals. The second chip is a digital buffer that allows for a significant reduction of the connection from the front-end module to the outside world. In this paper, the results achieved on the first complete prototype of the front-end system for the SDDs of ALICE are presented

    Event Generators for Bhabha Scattering

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    The results obtained by the "Event Generators for Bhabha Scattering" working group during the CERN Workshop "Physics at LEP2" (1994/1995) are presented.Comment: 70 pages, PostScript file. To appear in the Report of the Workshop on Physics at LEP2, G. Altarelli T. Sjostrand and F. Zwirner ed

    DT Sector Collector electronics design and construction

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    The CMS detector at LHC is equipped with Drift Tubes (DT) chambers for muon detection and triggering in the barrel region. The Sector Collector (SC) modules collect the track segments reconstructed by on-chamber trigger electronics. Data from different chambers are aligned in time and sent to the subsequent reconstruction processors via optical links. Several FPGA devices performing the processing of the data were designed in VHDL, including spy features to monitor the trigger data flow. A test jig was set up with custom hardware and software in order to fully validate final production boards. Installation and commissioning in CMS provided first experience with the synchronization and monitoring tools

    Samarium iodide-promoted asymmetric Reformatsky reaction of 3-(2-Haloacyl)-2-oxazolidinones with enals

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    3-(2-Haloacyl)-2-oxazolidinones were shown to react with enals in an asymmetric SmI2-promoted Reformatsky reaction to give stereochemically well-defined 3-hydroxy-4-alkenyl- and 3-hydroxy-2-methyl-4-alkenyl imides. Chirality transfer of the Evans (S)-oxazolidinone unit via a Zimmerman-Traxler-like transition state resulted in Reformatsky products with a relative syn-configuration. The absolute configuration of compounds obtained is opposite to the corresponding products obtained via aldol addition of boron enolates to enals using the same Evans oxazolidinones

    Design and Test of the Off-Detector Electronics for the CMS Barrel Muon Trigger

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    Drift Tubes chambers are used in the CMS barrel for tagging the passage of high Pt muons generated in a LHC event and for triggering the CMS data read out. The Sector Collector (SC) system synchronizes the track segments built by trigger modules on the chambers and deliver them to reconstruction processors (Track Finder, TF) that assemble full muon tracks. Then, the Muon Sorter (MS) has to select the best four candidates in the barrel and to filter fake muons generated by the TF system redundancy. The hardware implementations of the Sector Collector and Muon Sorter systems satisfy radiation, I/O and fast timing constraints using several FPGA technologies. The hardware was tested with custom facilities, integrated with other trigger subsystems, and operated in a beam test. A test beam on a 40 MHz bunched beam validated the local trigger electronics and off-detector prototype cards and the synchronization tools. The CMS Magnet Test and Cosmic challenge in 2006 proved stable and reliable operation of the Drift Tubes trigger and its integration with other trigger systems and with the readout system. Constraints, design, test and operation of the modules are presented

    Antibacterial and antifungal activities of 2,3-pyrrolidinedione derivatives against oral pathogens

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    Among the novel approaches applied to antimicrobial drug development, natural product-inspired synthesis plays a major role, by providing biologically validated starting points. Tetramic acids, a class of natural products containing a 2,4-pyrrolidinedione ring system, have attracted considerable attention for their antibacterial, antiviral, antifungal and anticancer activities. On the contrary, compounds with a 2,3-pyrrolidinedione skeleton have been considerably less investigated. In this work, we established chemical routes to the substituted 2,3-pyrrolidinedione core, which enabled the introduction of a wide range of diversity. In the perspective of a potential application for oral healthcare, a number of analogues with various substituents on the 2,3-pyrrolidinedione core were investigated for their antimicrobial and antifungal activities. The most promising compound showed a significant antimicrobial activity on Streptococcus mutans and Candida albicans, comparable to that of chlorhexidine, the gold standard in oral healthcare

    Influence of the adamantyl moiety on the activity of biphenylacrylohydroxamic acid-based HDAC inhibitors

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    To investigate the influence of the adamantyl group on the biological properties of known HDAC inhibitors with a 4-phenylcinnamic skeleton, a series of compounds having the adamantyl moiety in the cap structure were synthesized and compared to the corresponding hydroxamic acids lacking this group. An unexpected finding was the substantial reduction of inhibitory activity toward the tested enzymes, in particular HDAC6, following the introduction of the adamantyl group. In spite of the reduced ability to function as HDAC inhibitors, the compounds containing the adamantyl moiety still retained a good efficacy as antiproliferative and proapoptotic agents. A selected compound (2c; ST3056) of this series exhibited an appreciable antitumor activity against the colon carcinoma xenograft HCT116
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