Intraoperative electrically auditory brainstem responses to monitor auditory functionality preservation during auditory brainstem implant application.

Background: Perceptual outcomes of individuals with neurofibromatosis type II implanted with auditory brainstem implant are poor, and many factors seem to be involved. Undoubtedly, the preservation of neural functionality is the crucial aspect. The aim of this study is to verify that the use of intraoperative electrically auditory brainstem responses can help to understand if there is neural damage related to the tumor, and / or surgery. Material and Methods: A retrospective case series analysis was performed to review data from 6 adult patients affected by neurofibromatosis type 2 who received an auditory brainstem implant. A correlation was sought between intraoperative electrophysiological data, auditory performance at 1 and 2.5 years of follow-up, and auditory brainstem implant stimulation levels. Results: Patients with a better perceptual outcomes were those with more intraoperative peaks and peaks with wider amplitudes in the electrically auditory brainstem response recordings. Conclusions: Electrically auditory brainstem responses used for auditory brainstem implant placement can be a valuable tool for monitoring the preservation of neural acoustic functionality

A Compact Solid State Detector for Small Angle Particle Tracking

MIDAS (MIcrostrip Detector Array System) is a compact silicon tracking telescope for charged particles emitted at small angles in intermediate energy photonuclear reactions. It was realized to increase the angular acceptance of the DAPHNE detector and used in an experimental program to check the Gerasimov-Drell-Hearn sum rule at the Mainz electron microtron, MAMI. MIDAS provides a trigger for charged hadrons, p/pi identification and particle tracking in the region 7 deg < theta < 16 deg. In this paper we present the main characteristics of MIDAS and its measured performances.Comment: 13 pages (9 figures). Submitted to NIM

Demonstration and Comparison of Operation of Photomultiplier Tubes at Liquid Argon Temperature

Liquified noble gases are widely used as a target in direct Dark Matter searches. Signals from scintillation in the liquid, following energy deposition from the recoil nuclei scattered by Dark Matter particles (e.g. WIMPs), should be recorded down to very low energies by photosensors suitably designed to operate at cryogenic temperatures. Liquid Argon based detectors for Dark Matter searches currently implement photo multiplier tubes for signal read-out. In the last few years PMTs with photocathodes operating down to liquid Argon temperatures (87 K) have been specially developed with increasing Quantum Efficiency characteristics. The most recent of these, Hamamatsu Photonics Mod. R11065 with peak QE up to about 35%, has been extensively tested within the R&D program of the WArP Collaboration. During these testes the Hamamatsu PMTs showed superb performance and allowed obtaining a light yield around 7 phel/keVee in a Liquid Argon detector with a photocathodic coverage in the 12% range, sufficient for detection of events down to few keVee of energy deposition. This shows that this new type of PMT is suited for experimental applications, in particular for new direct Dark Matter searches with LAr-based experiments

A new, very massive modular Liquid Argon Imaging Chamber to detect low energy off-axis neutrinos from the CNGS beam. (Project MODULAr)

The paper is considering an opportunity for the CERN/GranSasso (CNGS) neutrino complex, concurrent time-wise with T2K and NOvA, to search for theta_13 oscillations and CP violation. Compared with large water Cherenkov (T2K) and fine grained scintillators (NOvA), the LAr-TPC offers a higher detection efficiency and a lower backgrounds, since virtually all channels may be unambiguously recognized. The present proposal, called MODULAr, describes a 20 kt fiducial volume LAr-TPC, following very closely the technology developed for the ICARUS-T60o, and is focused on the following activities, for which we seek an extended international collaboration: (1) the neutrino beam from the CERN 400 GeV proton beam and an optimised horn focussing, eventually with an increased intensity in the framework of the LHC accelerator improvement program; (2) A new experimental area LNGS-B, of at least 50000 m3 at 10 km off-axis from the main Laboratory, eventually upgradable to larger sizes. A location is under consideration at about 1.2 km equivalent water depth; (3) A new LAr Imaging detector of at least 20 kt fiducial mass. Such an increase in the volume over the current ICARUS T600 needs to be carefully considered. It is concluded that a very large mass is best realised with a set of many identical, independent units, each of 5 kt, "cloning" the technology of the T600. Further phases may foresee extensions of MODULAr to meet future physics goals. The experiment might reasonably be operational in about 4/5 years, provided a new hall is excavated in the vicinity of the Gran Sasso Laboratory and adequate funding and participation are made available.Comment: Correspondig Author: C. Rubbia (E-mail: [email protected]), 33 pages, 11 figure

Discovery of underground argon with low level of radioactive 39Ar and possible applications to WIMP dark matter detectors

We report on the first measurement of 39Ar in argon from underground natural gas reservoirs. The gas stored in the US National Helium Reserve was found to contain a low level of 39Ar. The ratio of 39Ar to stable argon was found to be <=4x10-17 (84% C.L.), less than 5% the value in atmospheric argon (39Ar/Ar=8x10-16). The total quantity of argon currently stored in the National Helium Reserve is estimated at 1000 tons. 39Ar represents one of the most important backgrounds in argon detectors for WIMP dark matter searches. The findings reported demonstrate the possibility of constructing large multi-ton argon detectors with low radioactivity suitable for WIMP dark matter searches.Comment: 6 pages, 2 figures, 2 table

Identification of kitM541l somatic mutation in chronic eosinophilic leukemia, not otherwise specified and its implication in low-dose imatinib response

Activating mutations of KIT receptor tyrosine kinase have been reported in different neoplasms. The M541L KIT substitution (KITM541L) has been described to be associated with pediatric mastocytosis, to enhance growth rate of the affected cells and to confer higher sensitivity to imatinib therapy. We investigated the presence of KITM541L in five males with chronic eosinophilic leukemia, not otherwise specified (CEL, NOS), all negative for Platelet-derived growth factor-alpha (PDGFR) or PDGFRbeta abnormalities, which responded to imatinib therapy. To assess whether the mutation was constitutive or somatic in nature, we evaluated its presence analyzing either the neoplastic or normal cell population (epidermal cells or CD3-positive T lymphocytes). KITM541L substitution was found in 4 out of 5 patients and in all it was somatic in nature. All patients were treated with low dose imatinib (100 mg daily orally), achieving complete and persistent clinical and hematological remission (median follow-up 74 months). One patient relapsed after 50 months. Our study strongly suggests to search for the KITM541L in patients with CEL, NOS, negative for PDGFRalpha and PDGFRbeta abnormalities, to identify a subgroup of cases who may benefit from low dose imatinib therapy

Single hadron response measurement and calorimeter jet energy scale uncertainty with the ATLAS detector at the LHC

The uncertainty on the calorimeter energy response to jets of particles is derived for the ATLAS experiment at the Large Hadron Collider (LHC). First, the calorimeter response to single isolated charged hadrons is measured and compared to the Monte Carlo simulation using proton-proton collisions at centre-of-mass energies of sqrt(s) = 900 GeV and 7 TeV collected during 2009 and 2010. Then, using the decay of K_s and Lambda particles, the calorimeter response to specific types of particles (positively and negatively charged pions, protons, and anti-protons) is measured and compared to the Monte Carlo predictions. Finally, the jet energy scale uncertainty is determined by propagating the response uncertainty for single charged and neutral particles to jets. The response uncertainty is 2-5% for central isolated hadrons and 1-3% for the final calorimeter jet energy scale.Comment: 24 pages plus author list (36 pages total), 23 figures, 1 table, submitted to European Physical Journal