Encontrados 9 documentos, a visualizar página 1 de 1
Avaliação do sequestro do óxido nítrico (NO) pelo extrato metanólico da alga Br...
Maia,Robinson M.; Moura,Carlos W. N.; Bispo,Vanderson S.; Santos,João L. A.; Santana,Rafael S.; Matos,Humberto R.O excesso de óxido nítrico (NO) produzido por indução da enzima óxido nítrico sintase (iNOS) participa do desenvolvimento de inúmeras desordens que conduzem à perda da homeostasia. O estresse oxidativo gerado pelo aumento da produção endógena de NO pode levar a efeitos de toxidade induzida, tais como peroxidação lipídica, nitração de proteínas e danos ao DNA. Compostos que sejam capazes de sequestrar o radical ...
Measurements of neutrons produced by high-energy muons at the Boulby Undergroun...
Araújo, H. M.; Blockley, J.; Bungau, C.; Carson, M. J.; Chagani, H.; Daw, E.; Edwards, B.; Ghag, C.; Korolkova, E. V.; Kudryavtsev, V. A.We present the first measurements of the muon-induced neutron flux at the Boulby Underground Laboratory. The experiment was carried out with an 0.73 tonne liquid scintillator that also served as an anticoincidence system for the ZEPLIN-II direct dark matter search. The experimental method exploited the delayed coincidences between high-energy muon signals and gamma-rays from radiative neutron capture on hydroge...
The ZEPLIN II dark matter detector: Data acquisition system and data reduction
Alner, G. J.; Araújo, H. M.; Bewick, A.; Bungau, C.; Camanzi, B.; Carson, M. J.; Chagani, H.; Chepel, V.; Cline, D.; Davidge, D.; Davies, J. C.; Daw, E.ZEPLIN II is a two-phase (liquid/gas) xenon dark matter detector searching for WIMP-nucleon interactions. In this paper we describe the data acquisition system used to record the data from ZEPLIN II and the reduction procedures which parameterise the data for subsequent analysis. ; http://www.sciencedirect.com/science/article/B6TJM-4R40SHG-9/1/eea3463e234b214a8a5d521b721d303a
First limits on WIMP nuclear recoil signals in ZEPLIN-II: A two-phase xenon det...
Alner, G. J.; Araújo, H. M.; Bewick, A.; Bungau, C.; Camanzi, B.; Carson, M. J.; Cashmore, R. J.; Chagani, H.; Chepel, V.; Cline, D.; Davidge, D.Results are presented from the first underground data run of ZEPLIN-II, a 31 kg two-phase xenon detector developed to observe nuclear recoils from hypothetical weakly interacting massive dark matter particles. Discrimination between nuclear recoils and background electron recoils is afforded by recording both the scintillation and ionisation signals generated within the liquid xenon, with the ratio of these sig...
The ZEPLIN III Detector; Results from Surface Calibrations
Sumner, T. J.; Akimov, D. Yu.; Alner, G. J.; Araújo, H. M.; Bewick, A.; Bungau, C.; Burenkov, A. A.; Carson, M. J.; Chagani, H.; Chepel, V.; Cline, D.ZEPLIN-III is a direct dark-matter search instrument using liquid xenon as a target.Both the scintillation light and the ionisation charge are measured.The instrument has been built and it is currently being testing in a surface laboratory.We present results from some of the initial testing, including design thermal control system verification, photomultiplier calibration (including spectral measurements with 6...
Limits on spin-dependent WIMP-nucleon cross-sections from the first ZEPLIN-II data
Alner, G. J.; Araújo, H. M.; Bewick, A.; Bungau, C.; Camanzi, B.; Carson, M. J.; Cashmore, R. J.; Chagani, H.; Chepel, V.; Cline, D.; Davidge, D.The first underground data run of the ZEPLIN-II experiment has set a limit on the nuclear recoil rate in the two-phase xenon detector for direct dark matter searches. In this Letter the results from this run are converted into the limits on spin-dependent WIMP-proton and WIMP-neutron cross-sections. The minimum of the curve for WIMP-neutron cross-section corresponds to 7×10-2 pb at a WIMP mass of around 65 GeV....
The ZEPLIN-III dark matter detector: Instrument design, manufacture and commiss...
Akimov, D. Yu.; Alner, G. J.; Araújo, H. M.; Bewick, A.; Bungau, C.; Burenkov, A. A.; Carson, M. J.; Chagani, H.; Chepel, V.; Cline, D.; Davidge, D.We present details of the technical design, manufacture and testing of the ZEPLIN-III dark matter experiment. ZEPLIN-III is a two-phase xenon detector which measures both the scintillation light and the ionisation charge generated in the liquid by interacting particles and radiation. The instrument design is driven by both the physics requirements and by the technology requirements surrounding the use of liquid...
Vein of Galen aneurysm in an adult: case report
Marques,Robinson M.; Lobão,Carlos A.F.; Sassaki,Viviane S.; Aguiar,Luiz R.Vein of Galen aneurysm is a rare pathology, representing less than 1% of intracranial vascular malformations. We report on a 65 years-old man who experienced a generalized tonic-clonic seizure. Brain imaging showed a large calcified expanding mass in the pineal region, confirming the diagnosis of a vein of Galen aneurysm. Because of the spontaneous thrombosis of the malformation, there was no need for microsurg...
The ZEPLIN-III dark matter detector: Performance study using an end-to-end simu...
Araújo, H. M.; Akimov, D. Yu.; Alner, G. J.; Bewick, A.; Bungau, C.; Camanzi, B.; Carson, M. J.; Chepel, V.; Chagani, H.; Davidge, D.; Davies, J. C.We present results from a GEANT4-based Monte Carlo tool for end-to-end simulations of the ZEPLIN-III dark matter experiment. ZEPLIN-III is a two-phase detector which measures both the scintillation light and the ionisation charge generated in liquid xenon by interacting particles and radiation. The software models the instrument response to radioactive backgrounds and calibration sources, including the generati...
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