584 research outputs found

    Rethinking elective cataract surgery diagnostics, assessments, and tools after the COVID-19 pandemic experience and beyond: Insights from the EUROCOVCAT group

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    The progressive deterioration of the visual function in patients on waiting lists for cataract surgery has a negative impact on their quality of life, especially in the elderly population. Patient waiting times for cataract surgeries in many healthcare settings have increased recently due to the prolonged stop or slowdown of elective cataract surgery as a result of coronavirus disease 19 (COVID-19). The aim of this review is to highlight the impact of such a “de-prioritization” of cataract surgery and to summarize some critical issues and useful hints on how to reorganize cataract pathways, with a special focus on perioperative diagnostic tools during the recovery phase and beyond. The experiences of a group of surgeons originating from nine different countries, named the European COVID-19 Cataract Group (EUROCOVCAT), have been combined with the literature and recommendations from scientific ophthalmic societies and healthcare institutions. Key considerations for elective cataract surgery should include the reduction of the number of unnecessary visits and examinations, adoption of precautionary measures, and implementation of telemedicine instruments. New strategies should be adopted to provide an adequate level of assistance and to guarantee safety conditions. Flexibility will be the watchword and regular updates would be necessary following scientific insights and the development of the pandemic

    High sensitivity characterization of an ultrahigh purity NaI(Tl) crystal scintillator with the SABRE proof-of-principle detector

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    We present new results on the radiopurity of a 3.4-kg NaI(Tl) crystal scintillator operated in the SABRE proof-of-principle detector setup. The amount of potassium contamination, determined by the direct counting of radioactive K40, is found to be 2.2±1.5 ppb, lowest ever achieved for NaI(Tl) crystals. With the active veto, the average background rate in the crystal in the 1-6 keV energy region of interest (ROI) is 1.20±0.05 counts/day/kg/keV, which is a breakthrough since the DAMA/LIBRA experiment. Our background model indicates that the rate is dominated by Pb210 and that about half of this contamination is located in the polytetrafluoroethylene reflector. We discuss ongoing developments of the crystal manufacture aimed at the further reduction of the background, including data from purification by zone refining. A projected background rate lower than ∼0.2 counts/day/kg/keV in the ROI is within reach. These results represent a benchmark for the development of next-generation NaI(Tl) detector arrays for the direct detection of dark matter particles

    Italian Society of Rheumatology recommendations for the management of gout.

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    Objective: Gout is the most common arthritis in adults. Despite the availability of valid therapeutic options, the management of patients with gout is still suboptimal. The Italian Society of Rheumatology (SIR) aimed to update, adapt to national contest and disseminate the 2006 EULAR recommendations for the management of gout. Methods: The multidisciplinary group of experts included rheumatologists, general practitioners, internists, geriatricians, nephrologists, cardiologists and evidence-based medicine experts. To maintain consistency with EULAR recommendations, a similar methodology was utilized by the Italian group. The original propositions were translated in Italian and priority research queries were identified through a Delphi consensus approach. A systematic search was conducted for selected queries. Efficacy and safety data on drugs reported in RCTs were combined in a meta-analysis where feasible. The strength of recommendation was measured by utilising the EULAR ordinal and visual analogue scales. Results: The original 12 propositions were translated and adapted to Italian context. Further evidences were collected about the role of diet in the non-pharmacological treatment of gout and the efficacy of oral corticosteroids and low-dose colchicine in the management of acute attacks. Statements concerning uricosuric treatments were withdrawn and replaced with a proposition focused on a new urate lowering agent, febuxostat. A research agenda was developed to identify topics still not adequately investigated concerning the management of gout. Conclusions: The SIR has developed updated recommendations for the management of gout adapted to the Italian healthcare system. Their implementation in clinical practice is expected to improve the management of patients with gout

    Characterization of SABRE crystal NaI-33 with direct underground counting

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    Ultra-pure NaI(Tl) crystals are the key element for a model-independent verification of the long standing DAMA result and a powerful means to search for the annual modulation signature of dark matter interactions. The SABRE collaboration has been developing cutting-edge techniques for the reduction of intrinsic backgrounds over several years. In this paper we report the first characterization of a 3.4 kg crystal, named NaI-33, performed in an underground passive shielding setup at LNGS. NaI-33 has a record low 39K contamination of 4.3 ± 0.2 ppb as determined by mass spectrometry. We measured a light yield of 11.1 ± 0.2 photoelectrons/keV and an energy resolution of 13.2% (FWHM/E) at 59.5 keV. We evaluated the activities of 226Ra and 228Th inside the crystal to be 5.9±0.6μBq/kg and 1.6±0.3μBq/kg, respectively, which would indicate a contamination from 238U and 232Th at part-per-trillion level. We measured an activity of 0.51 ± 0.02 mBq/kg due to 210Pb out of equilibrium and a α quenching factor of 0.63 ± 0.01 at 5304 keV. We illustrate the analyses techniques developed to reject electronic noise in the lower part of the energy spectrum. A cut-based strategy and a multivariate approach indicated a rate, attributed to the intrinsic radioactivity of the crystal, of ∼ 1 count/day/kg/keV in the [5–20] keV region

    Characterization of SABRE crystal NaI-33 with direct underground counting

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    Ultra-pure NaI(Tl) crystals are the key element for a model-independent verification of the long standing DAMA result and a powerful means to search for the annual modulation signature of dark matter interactions. The SABRE collaboration has been developing cutting-edge techniques for the reduction of intrinsic backgrounds over several years. In this paper we report the first characterization of a 3.4 kg crystal, named NaI-33, performed in an underground passive shielding setup at LNGS. NaI-33 has a record low 39^{39}K contamination of 4.3±\pm0.2 ppb as determined by mass spectrometry. We measured a light yield of 11.1±\pm0.2 photoelectrons/keV and an energy resolution of 13.2% (FWHM/E) at 59.5 keV. We evaluated the activities of 226^{226}Ra and 228^{228}Th inside the crystal to be 5.9±0.6μ5.9\pm0.6 \muBq/kg and 1.6±0.3μ1.6\pm0.3 \muBq/kg, respectively, which would indicate a contamination from 238^{238}U and 232^{232}Th at part-per-trillion level. We measured an activity of 0.51±\pm0.02 mBq/kg due to 210^{210}Pb out of equilibrium and a α\alpha quenching factor of 0.63±\pm0.01 at 5304 keV. We illustrate the analyses techniques developed to reject electronic noise in the lower part of the energy spectrum. A cut-based strategy and a multivariate approach indicated a rate, attributed to the intrinsic radioactivity of the crystal, of \sim1 count/day/kg/keV in the [5-20] keV region

    Association Between Severity of COVID-19 Respiratory Disease and Risk of Obstructive Sleep Apnea

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    Objectives: The purpose of this observational retrospective study was to evaluate, in patients with a severe acute respiratory syndrome coronavirus 2 infection, the association between the severity of coronavirus disease 2019 (COVID-19) respiratory illness and the risk of infected patients to develop obstructive sleep apnea (OSA). Methods: Ninety-six patients with confirmed COVID-19 infection were enrolled in the study. The STOP-BANG questionnaire to investigate the risk of the OSA syndrome was filled in by the patients at admission. The enrolled patients were divided into 2 groups according to the respiratory disease: group 1 (72 patients), hospitalized patients undergoing conventional oxygen therapy; group 2 (24 patients), patients requiring enhanced respiratory support. STOP-BANG results of these 2 groups were compared to observe whether patients with high OSA risk more frequently presented a severe form of COVID-19. Results: 41.6% of the patients in group 2 had a STOP-BANG score between 5 and 8 (high risk of having apnea); in contrast, 20.8% of the patients in group 1 had a STOP-BANG score between 5 and 8, with a statistically significant difference between the 2 groups (P =.05). A complementary trend was observed regarding the proportion of patients in the range 0 to 2, which classifies patients at a low risk of OSA (48.6% vs 20.8% for groups 1 and 2, P =.01). Conclusions: According to our data, the chances of having a severe case of COVID-19 should be considered in patients at high risk of OSA. Current Knowledge/Study Rationale: Emerging research suggests that OSA could represent a potentially important risk factor for the severe forms of COVID-19. The purpose of this observational retrospective study was to evaluate the potential association between OSA and the severity of COVID-19 disease. Study Impact: According to our data, the likelihood of contracting a severe form of COVID-19 disease should be considered in patients at high risk of OSA

    Borexino's search for low-energy neutrinos associated with gravitational wave events from GWTC-3 database

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    The search for neutrino events in correlation with gravitational wave (GW) events for three observing runs (O1, O2 and O3) from 09/2015 to 03/2020 has been performed using the Borexino data-set of the same period. We have searched for signals of neutrino-electron scattering with visible energies above 250 keV within a time window of 1000 s centered at the detection moment of a particular GW event. The search was done with three visible energy thresholds of 0.25, 0.8 and 3.0 MeV.Two types of incoming neutrino spectra were considered: the mono-energetic line and the spectrum expected from supernovae. The same spectra were considered for electron antineutrinos detected through inverse beta-decay (IBD) reaction. GW candidates originated by merging binaries of black holes (BHBH), neutron stars (NSNS) and neutron star and black hole (NSBH) were analysed separately. Additionally, the subset of most intensive BHBH mergers at closer distances and with larger radiative mass than the rest was considered. In total, follow-ups of 74 out of 93 gravitational waves reported in the GWTC-3 catalog were analyzed and no statistically significant excess over the background was observed. As a result, the strongest upper limits on GW-associated neutrino and antineutrino fluences for all flavors (\nu_e, \nu_\mu, \nu_\tau) have been obtained in the (0.5 - 5.0) MeV neutrino energy range.Comment: 13 pages, 8 figure

    The study of neutrinos and antineutrinos from astrophysical sources by Borexino

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    The recent observation of CNO solar neutrinos by Borexino (BX) has proven the high potential offered by large underground ultrapure liquid scintillators to disclose weak neutrino and antineutrino fluxes. Supernovae explosions, gamma-ray bursts, solar flares and Gravitational Waves (GW) are among the possible extra-terrestrial sources of neutrinos and antineutrinos. The extreme radiopurity of the BX detector has already allowed to get the best upper limits on all flavor fluences in the few MeV energy range from gamma ray bursts, to set limits on the diffuse supernova antineutrino background in the unexplored energy region below 8 MeV and to get the strongest upper limits on fast radio bursts associated neutrino fluences up to 50 MeV. Recently, BX has searched for neutrino events in correlation with GW events from 2015 to 2020 using the BX data-set of the same periods. The strongest upper limits on GW-associated neutrino and antineutrino fluences have been obtained in the (0.5 - 5.0) MeV neutrino energy range

    Novel techniques for alpha/beta pulse shape discrimination in Borexino

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    Borexino could efficiently distinguish between alpha and beta radiation in its liquid scintillator by the characteristic time profile of their scintillation pulse. This alpha/beta discrimination, first demonstrated at the tonne scale in the Counting Test Facility prototype, was used throughout the lifetime of the experiment between 2007 and 2021. With this method, alpha events are identified and subtracted from the beta-like solar neutrino events. This is particularly important in liquid scintillator as alpha scintillation is quenched many-fold. In Borexino, the prominent Po-210 decay peak was a background in the energy range of electrons scattered from Be-7 solar neutrinos. Optimal alpha-beta discrimination was achieved with a "multi-layer perceptron neural network", which its higher ability to leverage the timing information of the scintillation photons detected by the photomultiplier tubes. An event-by-event, high efficiency, stable, and uniform pulse shape discrimination was essential in characterising the spatial distribution of background in the detector. This benefited most Borexino measurements, including solar neutrinos in the \pp chain and the first direct observation of the CNO cycle in the Sun. This paper presents the key milestones in alpha/beta discrimination in Borexino as a term of comparison for current and future large liquid scintillator detectorsComment: 13 pages, 14 figure
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