268 research outputs found

    Computer Simulation of the Cool Down of the ATLAS Liquid Argon Barrel Calorimeter

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    The ATLAS electromagnetic barrel calorimeter consists of a liquid argon detector with a total mass of 120 tonnes. This highly complicated structure, fabricated from copper, lead, stainless steel and glass-fiber reinforced epoxy will be placed in an aluminum cryostat. The cool down process of the detector will be limited by the maximum temperature differences accepted by the composite structure so as to avoid critical mechanical stresses. A computer program simulating the cool down of the detector by calculating the local heat transfer throughout a simplified model has been developed. The program evaluates the cool down time as a function of different contact gasses filling the spaces within the detector

    Cryogenics for the Large Hadron Collider Experiments

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    High Energy Physics experiments have frequently adopted cryogenic versions of their apparatus to achieve the desired performance. Among the four new experiments for the CERN Large Hadron Collider (LHC) the two largest, ATLAS and CMS, include spectrometers using 4.5 K superconducting magnets and detectors filled with liquid argon at 87 K, respectively for particle momentum and energy measurements. These detectors are of unprecedented size and complexity and the definition of the associated cryogenic systems is the result of a collaboration between CERN and several external institutes all around the world. A review of the various systems is presented with particular emphasis to the basic cooling principles, the special cryogenic features and the operation scenarios

    PeroxiBase: a database with new tools for peroxidase family classification

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    Peroxidases (EC 1.11.1.x), which are encoded by small or large multigenic families, are involved in several important physiological and developmental processes. They use various peroxides as electron acceptors to catalyse a number of oxidative reactions and are present in almost all living organisms. We have created a peroxidase database (http://peroxibase.isb-sib.ch) that contains all identified peroxidase-encoding sequences (about 6000 sequences in 940 organisms). They are distributed between 11 superfamilies and about 60 subfamilies. All the sequences have been individually annotated and checked. PeroxiBase can be consulted using six major interlink sections ‘Classes’, ‘Organisms’, ‘Cellular localisations’, ‘Inducers’, ‘Repressors’ and ‘Tissue types’. General documentation on peroxidases and PeroxiBase is accessible in the ‘Documents’ section containing ‘Introduction’, ‘Class description’, ‘Publications’ and ‘Links’. In addition to the database, we have developed a tool to classify peroxidases based on the PROSITE profile methodology. To improve their specificity and to prevent overlaps between closely related subfamilies the profiles were built using a new strategy based on the silencing of residues. This new profile construction method and its discriminatory capacity have been tested and validated using the different peroxidase families and subfamilies present in the database. The peroxidase classification tool called PeroxiScan is accessible at the following address: http://peroxibase.isb-sib.ch/peroxiscan.php

    New cryogenic facilities for testing superconducting equipments for the CERN Large Hadron Collider

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    CERN's major project, the Large Hadron Collider (LHC), has moved to an implementation phase with machine construction to be completed by 2005. To achieve the design proton-proton centre of mass energy of 14 TeV in the given 27 km circumference LEP tunnel, the LHC will make an extensive use of high-field superconducting magnets using Nb-Ti filament operated at 1.9 K. In order to test, on the one han d, the superconducting cables of the magnets and, on the other hand, the expected performance of several of these magnets assembled in a string representing the lattice period of the machine (107 m lo ng), CERN has installed new cryogenic test facilities. The paper briefly describes these new facilities with all their associated equipments

    Cryogenics for CERN experiments: past, present and future

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    Use of cryogenics at CERN was originated (in the 1960s) by bubble chambers and the associated s.c. solenoids. Complex cryoplants were installed to provide cooling at LH2 and LHe temperatures. Continuity (in the 1970s) in He cryogenics for experiments was provided by spectrometer magnets for fixed target physics of the SPS accelerator. More recently (in the 1980s), large "particle-transparent" s.c. solenoids for collider experiments (LEP) have been built demanding new cryoplants. The LHC experiments (in the 2000s) will continue the tradition with s.c. dipoles (ALICE and LHCb), solenoids (CMS, ATLAS) and toroids (ATLAS) of unusual size. Cryogenics for experiments using noble liquids follows the same trend since the development (in the 1970s) of the first shower LAr detectors. A LKr calorimeter (about 10 m3) will be operated in 1996 and the ATLAS experiment foresees a set of three huge LAr calorimeters (almost 90 m3 total volume of liquid) to be installed underground

    Chemoradiotherapy (Gemox plus helical tomotherapy) for unresectable locally advanced pancreatic cancer: A phase II study

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    The aim of the study was to evaluate the safety and efficacy of a new chemo-radiotherapy regimen for patients with locally advanced pancreatic cancer (LAPC). Patients were treated as follows: gemcitabine 1000 mg/m2 on day 1, and oxaliplatin 100 mg/m2 on day 2, every two weeks (GEMOX regimen) for 4 cycles, 15 days off, hypofractionated radiotherapy (35 Gy in 7 fractions in 9 consecutive days), 15 days off, 4 additional cycles of GEMOX, restaging. From April 2011 to August 2016, a total of 42 patients with non resectable LAPC were enrolled. Median age was 67 years (range 41\u201375). Radiotherapy was well tolerated and the most frequently encountered adverse events were mild to moderate nausea and vomiting, abdominal pain and fatigue. In total, 9 patients underwent surgical laparotomy (5 radical pancreatic resection 1 thermoablation and 3 explorative laparotomy), 1 patient became operable but refused surgery. The overall resectability rate was 25%, while the R0 resection rate was 12.5%. At a median follow-up of 50 months, the median progression-free survival and overall survival were 9.3 (95% CI 6.2\u201314.9) and 15.8 (95% CI 8.2\u201323.4) months, respectively. The results demonstrate the feasibility of a new chemo-radiotherapy regimen as a potential treatment for unresectable LAPC

    Treatment of squamous cell carcinoma of the anal canal: A new strategies with anti-EGFR therapy and immunotherapy

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    The incidence of squamous cell carcinoma of the anal canal (SCAC) is increasing in both sexes but the standard treatment remains that of 20 years ago. However, interesting data have recently emerged on the use of anti-epidermal growth factor receptor (EGFR) agents and immunotherapy in advanced disease. Thus, new avenues of research are opening up that will hopefully lead to more effective therapeutic strategies. We provide an overview of the latest studies published on this tumor and discuss the possible future therapeutic options for combination therapy, anti-EGFR treatment and radiotherapy

    Melanoma metastasis mimicking gastric cancer: a challenge that starts from diagnosis

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    The gastrointestinal tract is an uncommon site of metastasis in melanoma. However, when the primary melanoma cannot be found, the diagnosis of gastric melanoma by endoscopic biopsy is problematic mainly because some tumors are amelanotic and do not contain melanin granules detectable by microscopy. A 56-year-old Caucasian man with melanoma was referred to us following an initial histopathological diagnosis via gastroscopy of poorly differentiated primary gastric carcinoma. A computerized tomography (CT) scan showed metastatic disease and on the basis of this information we started palliative chemotherapy. However, the atypical presentation of the disease with subcutaneous metastases prompted us to make a more in-depth evaluation. Immunohistochemical evaluation modified the diagnosis to melanoma. After only one cycle of chemotherapy, treatment was changed to dabrafenib + trametinib, which was better tolerated and initially induced a partial response. The patient is currently in good clinical condition 20 months after diagnosis. Our case report highlights the difficulty in diagnosing melanoma of the gastrointestinal tract and indicates the need for pathologists and clinicians to consider such a possibility when they are faced with a diagnosis of poorly differentiated gastric cancer and unusual sites of metastasis
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