Abstract
Radon-free clean rooms are essential for the production and
assembly of components adopted in low-background experiments. In
particular, long-lived radon decay products are often problematic
...for rare events searches, such as low energy neutrino interactions,
direct dark matter detection, and neutrinoless double beta decay.
These isotopes can easily deposit onto surfaces exposed to radon,
leading to a residual background that can limit the sensitivity of
experiments. In order to mitigate this background source,
construction of detectors in radon-reduced environments is
essential. In this framework, design and building of
radon-suppressed clean rooms require a deep understanding of the
radon behavior and the different sources of contamination. In the
paper, computation fluid-dynamics (CFD) analyses of the
radon-suppressed clean rooms built for the DarkSide-50 experiment
are reported. The numerical model including the main radon
contributions, such as structural materials, equipment, and
operators activity, provides very promising results in a remarkable
agreement with available experimental data, confirming the validity
of the current modelling approach for future applications.
For most of their existence, stars are fuelled by the fusion of hydrogen into helium. Fusion proceeds via two processes that are well understood theoretically: the proton-proton (pp) chain and the ...carbon-nitrogen-oxygen (CNO) cycle
. Neutrinos that are emitted along such fusion processes in the solar core are the only direct probe of the deep interior of the Sun. A complete spectroscopic study of neutrinos from the pp chain, which produces about 99 per cent of the solar energy, has been performed previously
; however, there has been no reported experimental evidence of the CNO cycle. Here we report the direct observation, with a high statistical significance, of neutrinos produced in the CNO cycle in the Sun. This experimental evidence was obtained using the highly radiopure, large-volume, liquid-scintillator detector of Borexino, an experiment located at the underground Laboratori Nazionali del Gran Sasso in Italy. The main experimental challenge was to identify the excess signal-only a few counts per day above the background per 100 tonnes of target-that is attributed to interactions of the CNO neutrinos. Advances in the thermal stabilization of the detector over the last five years enabled us to develop a method to constrain the rate of bismuth-210 contaminating the scintillator. In the CNO cycle, the fusion of hydrogen is catalysed by carbon, nitrogen and oxygen, and so its rate-as well as the flux of emitted CNO neutrinos-depends directly on the abundance of these elements in the solar core. This result therefore paves the way towards a direct measurement of the solar metallicity using CNO neutrinos. Our findings quantify the relative contribution of CNO fusion in the Sun to be of the order of 1 per cent; however, in massive stars, this is the dominant process of energy production. This work provides experimental evidence of the primary mechanism for the stellar conversion of hydrogen into helium in the Universe.
We report the measurement of sub-MeV solar neutrinos through the use of their associated Cherenkov radiation, performed with the Borexino detector at the Laboratori Nazionali del Gran Sasso. The ...measurement is achieved using a novel technique that correlates individual photon hits of events to the known position of the Sun. In an energy window between 0.54 to 0.74 MeV, selected using the dominant scintillation light, we have measured 10 887_{-2103}^{+2386}(stat)±947(syst) (68% confidence interval) solar neutrinos out of 19 904 total events. This corresponds to a ^{7}Be neutrino interaction rate of 51.6_{-12.5}^{+13.9} counts/(day·100 ton), which is in agreement with the standard solar model predictions and the previous spectroscopic results of Borexino. The no-neutrino hypothesis can be excluded with >5σ confidence level. For the first time, we have demonstrated the possibility of utilizing the directional Cherenkov information for sub-MeV solar neutrinos, in a large-scale, high light yield liquid scintillator detector. This measurement provides an experimental proof of principle for future hybrid event reconstruction using both Cherenkov and scintillation signatures simultaneously.
We report on searches for neutrinos and antineutrinos from astrophysical sources performed with the Borexino detector at the Laboratori Nazionali del Gran Sasso in Italy. Electron antineutrinos (ν¯e) ...are detected in an organic liquid scintillator through the inverse β-decay reaction. In the present work we set model-independent upper limits in the energy range 1.8–16.8 MeV on neutrino fluxes from unknown sources that improve our previous results, on average, by a factor 2.5. Using the same data set, we first obtain experimental constraints on the diffuse supernova ν¯e fluxes in the previously unexplored region below 8 MeV. A search for ν¯e in the solar neutrino flux is also presented: the presence of ν¯e would be a manifestation of a non-zero anomalous magnetic moment of the neutrino, making possible its conversion to antineutrinos in the strong magnetic field of the Sun. We obtain a limit for a solar ν¯e flux of 384 cm–2 s–1 (90% C.L.), assuming an undistorted solar 8B neutrinos energy spectrum, that corresponds to a transition probability pνe→ν¯e< 7.2 × 10–5 (90% C.L.) for Eν¯e > 1.8 MeV. At lower energies, by investigating the spectral shape of elastic scattering events, we obtain a new limit on solar 7Be-νe conversion into ν¯e of pνe→ν¯e< 0.14 (90% C.L.) at 0.862 MeV. Last, we investigate solar flares as possible neutrino sources and obtain the strongest up-to-date limits on the fluence of neutrinos of all flavor neutrino below 3–7 MeV. Assuming the neutrino flux to be proportional to the flare’s intensity, we exclude an intense solar flare as the cause of the observed excess of events in run 117 of the Cl-Ar Homestake experiment.
AIM: To assess the associations of chocolate consumption with neurocognitive function, brain lesions on magnetic resonance imaging (MRI), and cardiovascular outcome in patients with atrial ...fibrillation (AF).
METHODS: We analysed data from patients of two prospective multicentre Swiss atrial fibrillation cohort studies (Swiss-AF) and (BEAT-AF). Assessments of MRI findings and neurocognitive function were performed only in the Swiss-AF population (in 1727 of 2415 patients 71.5% with a complete data set), as patients enrolled in BEAT-AF were not systematically evaluated for these outcomes. Otherwise, the two cohorts had an equivalent set of clinical assessments. Clinical outcome analysis was performed in 3931 patients of both cohorts. Chocolate consumption was assessed by questionnaire. Patients were categorised as no/low chocolate consumption (No/Low-Ch) ≤1 servings/week, moderate chocolate consumption (Mod-Ch) >1–6 servings/week, and high chocolate consumption (High-Ch) >6 servings/week, respectively. Brain lesions were evaluated by MRI. Assessment of cognitive function was performed by neurocognitive functional testing and included global cognition measurement with a cognitive construct score. Cerebral MRI and cognition were evaluated at baseline. Cross-sectional associations between chocolate consumption and MRI findings were analysed by multivariate logistic regression models and associations with neurocognitive function by multivariate linear regression models. Clinical outcome events during follow-up were recorded and assessed by a clinical event committee. The associations between chocolate consumption and clinical outcomes were evaluated by Cox regression models. The median follow-up time was 6 years.
RESULTS: Chocolate consumption was not associated with prevalence or volume of vascular brain lesions on MRI, nor major adverse cardiac events (ischaemic stroke, myocardial infarction, cardiovascular death). However, No/Low-Ch was independently associated with a lower cognitive construct score compared to Mod-Ch (No/Low-Ch vs. Mod-Ch: coeff. –0.05, 95% CI –0.10–0), whereas other neurocognitive function tests were not independently associated with chocolate consumption categories. In addition, there was a higher risk of heart failure hospitalisation (No/Low-Ch vs. Mod-Ch: HR 1.24, 95% CI 1.01–1.52) and of all-cause mortality (No/Low-Ch vs. Mod-Ch: HR 1.29, 95% CI 1.06–1.58) in No/Low-Ch compared to Mod-Ch. No significant associations with the evaluated outcomes were observed when High-Ch was compared to Mod-Ch.
CONCLUSION: While chocolate consumption was not associated with MRI findings and major adverse cardiac events in an atrial fibrillation population, No/Low-Ch was associated with a lower cognitive construct score, higher risk of heart failure hospitalisation and increased all-cause mortality compared to Mod-Ch.
ClinicalTrials.gov Identifier: NCT02105844
Acute calculus cholecystitis (ACC) has a high incidence in the general population. The presence of several areas of uncertainty, along with the availability of new evidence, prompted the current ...update of the 2016 WSES (World Society of Emergency Surgery) Guidelines on ACC.
The WSES president appointed four members as a scientific secretariat, four members as an organization committee and four members as a scientific committee, choosing them from the expert affiliates of WSES. Relevant key questions were constructed, and the task force produced drafts of each section based on the best scientific evidence from PubMed and EMBASE Library; recommendations were developed in order to answer these key questions. The quality of evidence and strength of recommendations were reviewed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) criteria (see https://www.gradeworkinggroup.org/ ). All the statements were presented, discussed and voted upon during the Consensus Conference at the 6th World Congress of the World Society of Emergency Surgery held in Nijmegen (NL) in May 2019. A revised version of the statements was voted upon via an online questionnaire until consensus was reached.
The pivotal role of surgery is confirmed, including in high-risk patients. When compared with the WSES 2016 guidelines, the role of gallbladder drainage is reduced, despite the considerable technical improvements available. Early laparoscopic cholecystectomy (ELC) should be the standard of care whenever possible, even in subgroups of patients who are considered fragile, such as the elderly; those with cardiac disease, renal disease and cirrhosis; or those who are generally at high risk for surgery. Subtotal cholecystectomy is safe and represents a valuable option in cases of difficult gallbladder removal.
ELC has a central role in the management of patients with ACC. The value of surgical treatment for high-risk patients should lead to a distinction between high-risk patients and patients who are not suitable for surgery. Further evidence on the role of clinical judgement and the use of clinical scores as adjunctive tools to guide treatment of high-risk patients and patients who are not suitable for surgery is required. The development of local policies for safe laparoscopic cholecystectomy is recommended.
BACKGROUND: Quantitative and semiquantitative methods have been proposed for the assessment of MR severity, and though all are associated with limitations. Measurement of vena contracta width (VCW) ...has been used in clinical practice. OBJECTIVE: To measure the VCW in dogs with different levels of MR severity. ANIMALS: Two hundred and seventy‐nine dogs were classified according to 5 levels of MR severity. METHODS: This was a retrospective study. EROA and regurgitant volume calculated by the PISA method, were measured and indexed to BSA. Descriptive statistics were calculated for VCW and VCW index for all categories of MR severity. Spearman's rank correlation coefficients (ρₛ) were calculated to compare the results of the different methods (VCW and VCW index vs RV PISA, RV PISA index, EROA, EROA index), and between VCW and VCW index versus MR severity. RESULTS: All Spearman's rank correlation coefficients were significant (P < .001). The median values of VCW resulted of 2.9 mm (IQR 3.4–2.5) and of 4.6 mm (IQR 5.4–4.1) in the groups previously classified as mild‐to‐moderate and moderate‐to‐severe, respectively. The median values of VCW index resulted of 4.4 mm/m²(IQR = 5.5–4.2) in mild‐to‐moderate MR and of 10.8 mm/m²(IQR = 12.8–9.4) in moderate‐to‐severe MR. CONCLUSION AND CLINICAL IMPORTANCE: This is not a validation study against any previously validated invasive gold standard, the VCW method has proved easy to employ and it might be an additional tool in quantifying disease severity that supports, rather than replace, data coming from other techniques in daily clinical practice and research.
Background
In the Hokusai VTE Cancer study, the risk of major bleeding was 2.9% higher in the edoxaban group compared with the dalteparin group, mainly due to more gastrointestinal bleedings in ...patients with gastrointestinal cancer. The identification of risk factors for gastrointestinal bleeding may help to guide the use of DOACs in these patients.
Objectives
To evaluate risk factors for gastrointestinal bleeding in patients with gastrointestinal cancer receiving edoxaban.
Patients/Methods
In this nested case‐control study in patients with gastrointestinal cancer randomized to edoxaban in the Hokusai VTE Cancer study, cases (patients with clinically relevant gastrointestinal bleeding during treatment) were randomly matched to three controls (patients who had no gastrointestinal bleeding). Data for the 4‐week period prior to bleeding were retrospectively collected. Odds ratios (ORs) were calculated in a crude conditional logistic regression model and a multivariable model adjusted for age, sex, and cancer type.
Results
Twenty‐four cases and 64 matched controls were included. In the multivariable analysis, advanced cancer, defined as regionally advanced or metastatic cancer (OR 3.6, 95% CI 1.01–12.6) and low hemoglobin levels (OR 4.8, 95% CI 1.5–16.0) were significantly associated with bleeding. There was no significant difference in patients with resected tumors (OR 0.4, 95% CI 0.1–1.4), or in patients on chemotherapy (OR 1.3, 95% CI 0.5–3.5).
Conclusion
Advanced cancer and low hemoglobin levels were associated with an increased risk of gastrointestinal bleeding in patients with gastrointestinal cancer receiving edoxaban. We were unable to identify other risk factors, mainly due to limited statistical power.
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