566 research outputs found

    Radiation Tolerance of CMOS Monolithic Active Pixel Sensors with Self-Biased Pixels

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    CMOS Monolithic Active Pixel Sensors (MAPS) are proposed as a technology for various vertex detectors in nuclear and particle physics. We discuss the mechanisms of ionizing radiation damage on MAPS hosting the the dead time free, so-called self bias pixel. Moreover, we discuss radiation hardened sensor designs which allow operating detectors after exposing them to irradiation doses above 1 Mra

    A vertex detector for the International Linear Collider based on CMOS sensors

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    The physics programme at the International Linear Collider (ILC) calls for a vertex detector (VD) providing unprecedented flavour tagging performances, especially for c-quarks and τ leptons. This requirement makes a very granular, thin and multi-layer VD installed very close to the interaction region mandatory. Additional constraints, mainly on read-out speed and radiation tolerance, originate from the beam background, which governs the occupancy and the radiation level the detector should be able to cope with. CMOS sensors are being developed to fulfil these requirements. This report addresses the ILC requirements (highly related to beamstrahlung), the main advantages and features of CMOS sensors, the demonstrated performances and the specific aspects of a VD based on this technology. The status of the main R&D directions (radiation tolerance, thinning procedure and read-out speed) are also presented

    Challenges in QCD matter physics - The Compressed Baryonic Matter experiment at FAIR

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    Substantial experimental and theoretical efforts worldwide are devoted to explore the phase diagram of strongly interacting matter. At LHC and top RHIC energies, QCD matter is studied at very high temperatures and nearly vanishing net-baryon densities. There is evidence that a Quark-Gluon-Plasma (QGP) was created at experiments at RHIC and LHC. The transition from the QGP back to the hadron gas is found to be a smooth cross over. For larger net-baryon densities and lower temperatures, it is expected that the QCD phase diagram exhibits a rich structure, such as a first-order phase transition between hadronic and partonic matter which terminates in a critical point, or exotic phases like quarkyonic matter. The discovery of these landmarks would be a breakthrough in our understanding of the strong interaction and is therefore in the focus of various high-energy heavy-ion research programs. The Compressed Baryonic Matter (CBM) experiment at FAIR will play a unique role in the exploration of the QCD phase diagram in the region of high net-baryon densities, because it is designed to run at unprecedented interaction rates. High-rate operation is the key prerequisite for high-precision measurements of multi-differential observables and of rare diagnostic probes which are sensitive to the dense phase of the nuclear fireball. The goal of the CBM experiment at SIS100 (sqrt(s_NN) = 2.7 - 4.9 GeV) is to discover fundamental properties of QCD matter: the phase structure at large baryon-chemical potentials (mu_B > 500 MeV), effects of chiral symmetry, and the equation-of-state at high density as it is expected to occur in the core of neutron stars. In this article, we review the motivation for and the physics programme of CBM, including activities before the start of data taking in 2022, in the context of the worldwide efforts to explore high-density QCD matter.Comment: 15 pages, 11 figures. Published in European Physical Journal

    CMOS pixel sensor development: a fast read-out architecture with integrated zero suppression

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    International audienceCMOS Monolithic Active Pixel Sensors (MAPS) have demonstrated their strong potential for tracking devices, particularly for flavour tagging. They are foreseen to equip several vertex detectors and beam telescopes. Most applications require high read-out speed, which imposes sensors to feature digital output with integrated zero suppression. The most recent development of MAPS at IPHC and IRFU addressing this issue will be reviewed. The design architecture, combining pixel array, column-level discriminators and zero suppression circuits, will be presented. Each pixel features a preamplifier and a correlated double sampling (CDS) micro-circuit reducing the temporal and fixed pattern noises. The sensor is fully programmable and can be monitored. It will equip experimental apparatus starting data taking in 2009/2010

    A ten thousand frames per second readout MAPS for the EUDET beam telescope

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    Designed and manufactured in a commercial CMOS 0.35 μm OPTO process for equipping the EUDET beam telescope, MIMOSA26 is the first reticule size pixel sensor with digital output and integrated zero suppression. It features a matrix of pixels with 576 rows and 1152 columns, covering an active area of ~224 mm2. A single point resolution of about 4 μm was obtained with a pixel pitch of 18.4 μm. Its architecture allows a fast readout frequency of ~10 k frames/s. The paper describes the chip design, test and major characterisation outcome

    Immunoregulatory gene polymorphisms in women with preeclampsia

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    The costimulatory molecules CD28, cytotoxic T-lymphocyte antigen-4 (CTLA-4) (cytotoxic T-lymphocyte-associated antigen-4) and inducible costimulator (ICOS) are believed to have a critical modulatory role in the immune response. However, few studies have been performed on the role of these immune regulatory molecules and their polymorphisms in women with preeclampsia (PE). the aim of our study was to evaluate the CTLA4 (+49 A/G) (rs 231775), CD28 (+17 T/C) (rs 3116496) and ICOS (-1564 T/C) (rs 4675378) gene polymorphisms in Brazilian women with PE. This case-control study included 130 patients with PE and 261 control women without any obstetric or systemic disorders. Genomic DNA was extracted from peripheral blood, and the polymorphism genotyping was performed by digesting the PCR products with the restriction endonucleases BbvI (CTLA-4), Afel (CD28) and AluI (ICOS). Data were analyzed by X(2) or Fisher's exact test; a P-value of < 0.05 was considered as significant. There were significant differences in the ICOS genotype and allelic frequencies between the PE and control groups (P=0.01 and P=0.01, respectively). We found a significantly lower frequency of the ICOS (-1564) T allele in women with mild PE compared with the controls. There were no differences in the CTLA-4 (+49 A/G) and CD28 (+17 T/C) genotypes and allelic frequencies between the PE patients and controls. Our data suggest that PE is associated with ICOS, but is not associated with the CTLA-4 or CD28 gene polymorphisms. Hypertension Research (2011) 34, 384-388; doi:10.1038/hr.2010.247; published online 16 December 2010Fundacao de Amparo a PesquisaCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Universidade Federal de São Paulo, Dept Obstet, BR-01415002 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Obstet, BR-01415002 São Paulo, BrazilFundacao de Amparo a Pesquisa: 07/57446-0Web of Scienc

    Predictors of response to pharmacological treatments in treatment-resistant schizophrenia - A systematic review and meta-analysis

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    Background: As the burden of treatment-resistant schizophrenia (TRS) on patients and society is high it is important to identify predictors of response to medications in TRS. The aim was to analyse whether baseline patient and study characteristics predict treatment response in TRS in drug trials. Methods: A comprehensive search strategy completed in PubMed, Cochrane and Web of Science helped identify relevant studies. The studies had to meet the following criteria: English language clinical trial of pharmacological treatment of TRS, clear definition of TRS and response, percentage of response reported, at least one baseline characteristic presented, and total sample size of at least 15. Meta-regression techniques served to explore whether baseline characteristics predict response to medication in TRS. Results: 77 articles were included in the systematic review. The overall sample included 7546 patients, of which 41% achieved response. Higher positive symptom score at baseline predicted higher response percentage. None of the other baseline patient or study characteristics achieved statistical significance at predicting response. When analysed in groups divided by antipsychotic drugs, studies of clozapine and other atypical antipsychotics produced the highest response rate. Conclusions: This meta-analytic review identified surprisingly few baseline characteristics that predicted treatment response. However, higher positive symptoms and the use of atypical antipsychotics - particularly clozapine -was associated with the greatest likelihood of response. The difficulty involved in the prediction of medication response in TRS necessitates careful monitoring and personalised medication management. There is a need for more investigations of the predictors of treatment response in TRS.Peer reviewe

    Prevalence and determinants of vitamin D deficiency and insufficiency among three immigrant groups in Finland : evidence from a population-based study using standardised 25-hydroxyvitamin D data

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    Objective: We investigated the determinants of serum 25-hydroxyvitamin D [S-25(OH)D] and dietary vitamin D sources among three immigrant groups in Finland and compared their S-25(OH)D to the general Finnish population. Design: Cross-sectional population-based Migrant Health and Wellbeing Study and the nationally representative Finnish Health 2011 Survey. S-25(OH)D was standardised according to the Vitamin D Standardisation Program. Vitamin D sources were assessed by interview. Setting: Six different municipalities in Finland (60 degrees-63 degrees N). Participants: Immigrants aged 18-64 years (446 Russians, 346 Somalis, 500 Kurds), 798 Finns aged 30-64 years. Results: The mean of S-25(OH)D was 64 (95 % CI 62, 66), 44 (95 % CI 41, 46), 35 (95 % CI 34, 37) and 64 (95 % CI 62, 66) nmol/l for Russians, Somalis, Kurds and Finns, respectively. S-25(OH)D among Somalis and Kurds was lower compared with Finns (P <0 center dot 001). The prevalence of vitamin D deficiency (S-25(OH)DPeer reviewe

    Airway obstruction, serum vitamin D and mortality in a 33-year follow-up study

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    Background and objective: Chronic obstructive pulmonary disease and low vitamin D status predict mortality, but their combined effect on mortality remains inconclusive. We aimed to investigate a joint effect of airway obstruction and vitamin D status on mortality in a nationally representative cohort. Methods: We analysed data of 6676 Finnish adults participating between 1978 and 1980 in a national health examination survey, undergoing spirometry and having all necessary data collected. We followed them up in national registers through record linkage until 31 December 2011. We categorised the subjects with obstruction using the lower limit of normal (LLN) and the measured serum 25-hydroxyvitamin-D (s-25(OH)D) into tertiles. Results: Both obstruction and low s-25(OH) D independently predicted mortality in a multivariate model adjusted also for age, sex, smoking, education, leisure physical activity, body mass index, asthma and serum C-reactive protein. However, a statistically significant (p = 0.007) interaction emerged: the adjusted mortality HRs (95% CI's) for s-25(OH)D in tertiles among the subjects without and with obstruction were 1.00 (lowest), 0.96 (0.87-1.05) and 0.89 (0.81-0.98); and 1.00, 0.96 (0.71-1.31) and 0.57 (0.40-0.80), respectively. Conclusions: In conclusion, obstruction and low s-25(OH)D predict mortality independently of each other. Our findings suggest that low vitamin D status might be particularly detrimental among subjects with obstruction.Peer reviewe
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