| 1. |
- Diakaki, M., et al.
(author)
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Towards the high-accuracy determination of the 238U fission cross section at the threshold region at CERN -€“ n_TOF
- 2016
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In: EPJ Web of Conferences. - : EDP Sciences. - 2100-014X.
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Conference paper (peer-reviewed)abstract
- The U-238 fission cross section is an international standard beyond 2 MeV where the fission plateau starts. However, due to its importance in fission reactors, this cross-section should be very accurately known also in the threshold region below 2 MeV. The U-238 fission cross section has been measured relative to the U-235 fission cross section at CERN - n_TOF with different detection systems. These datasets have been collected and suitably combined to increase the counting statistics in the threshold region from about 300 keV up to 3 MeV. The results are compared with other experimental data, evaluated libraries, and the IAEA standards.
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| 2. |
- Paradela, C., et al.
(author)
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High-accuracy determination of the 238U/235U fission cross section ratio up to ~1 GeV at n_TOF at CERN
- 2015
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In: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 91, s. 024602-
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Journal article (peer-reviewed)abstract
- The U238 to U235 fission cross section ratio has been determined at n_TOF up to ≈1 GeV, with two different detection systems, in different geometrical configurations. A total of four datasets has been collected and compared. They are all consistent to each other within the relative systematic uncertainty of 3–4%. The data collected at n_TOF have been suitably combined to yield a unique fission cross section ratio as a function of neutron energy. The result confirms current evaluations up to 200 MeV. Good agreement is also observed with theoretical calculations based on the INCL++/Gemini++ combination up to the highest measured energy. The n_TOF results may help solve a long-standing discrepancy between the two most important experimental datasets available so far above 20 MeV, while extending the neutron energy range for the first time up to ≈1 GeV.
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| 3. |
- Altavilla, R., et al.
(author)
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Anticoagulation After Stroke in Patients With Atrial Fibrillation: To Bridge or Not With Low-Molecular-Weight Heparin?
- 2019
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In: Stroke. - : Ovid Technologies (Wolters Kluwer Health). - 0039-2499 .- 1524-4628. ; 50:8, s. 2093-2100
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Journal article (peer-reviewed)abstract
- Background and Purpose- Bridging therapy with low-molecular-weight heparin reportedly leads to a worse outcome for acute cardioembolic stroke patients because of a higher incidence of intracerebral bleeding. However, this practice is common in clinical settings. This observational study aimed to compare (1) the clinical profiles of patients receiving and not receiving bridging therapy, (2) overall group outcomes, and (3) outcomes according to the type of anticoagulant prescribed. Methods- We analyzed data of patients from the prospective RAF and RAF-NOACs studies. The primary outcome was defined as the composite of ischemic stroke, transient ischemic attack, systemic embolism, symptomatic cerebral bleeding, and major extracerebral bleeding observed at 90 days after the acute stroke. Results- Of 1810 patients who initiated oral anticoagulant therapy, 371 (20%) underwent bridging therapy with full-dose low-molecular-weight heparin. Older age and the presence of leukoaraiosis were inversely correlated with the use of bridging therapy. Forty-two bridged patients (11.3%) reached the combined outcome versus 72 (5.0%) of the nonbridged patients (P=0.0001). At multivariable analysis, bridging therapy was associated with the composite end point (odds ratio, 2.3; 95% CI, 1.4-3.7; P<0.0001), as well as ischemic (odds ratio, 2.2; 95% CI, 1.3-3.9; P=0.005) and hemorrhagic (odds ratio, 2.4; 95% CI, 1.2-4.9; P=0.01) end points separately. Conclusions- Our findings suggest that patients receiving low-molecular-weight heparin have a higher risk of early ischemic recurrence and hemorrhagic transformation compared with nonbridged patients.
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| 4. |
- Paciaroni, M., et al.
(author)
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Hemorrhagic transformation in patients with acute ischemic stroke and atrial fibrillation: Time to initiation of oral anticoagulant therapy and outcomes
- 2018
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In: Journal of the American Heart Association. - 2047-9980. ; 7:22
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Journal article (peer-reviewed)abstract
- Background—In patients with acute ischemic stroke and atrial fibrillation, early anticoagulation prevents ischemic recurrence but with the risk of hemorrhagic transformation (HT). The aims of this study were to evaluate in consecutive patients with acute stroke and atrial fibrillation (1) the incidence of early HT, (2) the time to initiation of anticoagulation in patients with HT, (3) the association of HT with ischemic recurrences, and (4) the association of HT with clinical outcome at 90 days. Methods and Results—HT was diagnosed by a second brain computed tomographic scan performed 24 to 72 hours after stroke onset. The incidence of ischemic recurrences as well as mortality or disability (modified Rankin Scale scores >2) were evaluated at 90 days. Ischemic recurrences were the composite of ischemic stroke, transient ischemic attack, or systemic embolism. Among the 2183 patients included in the study, 241 (11.0%) had HT. Patients with and without HT initiated anticoagulant therapy after a mean 23.3 and 11.6 days, respectively, from index stroke. At 90 days, 4.6% (95% confidence interval, 2.3-8.0) of the patients with HT had ischemic recurrences compared with 4.9% (95% confidence interval, 4.0-6.0) of those without HT; 53.1% of patients with HT were deceased or disabled compared with 35.8% of those without HT. On multivariable analysis, HT was associated with mortality or disability (odds ratio, 1.71; 95% confidence interval, 1.24-2.35). Conclusions—In patients with HT, anticoagulation was initiated about 12 days later than patients without HT. This delay was not associated with increased detection of ischemic recurrence. HT was associated with increased mortality or disability. © 2018 The Authors.
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| 5. |
- Paciaroni, M., et al.
(author)
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Prediction of Early Recurrent Thromboembolic Event and Major Bleeding in Patients With Acute Stroke and Atrial Fibrillation by a Risk Stratification Schema The ALESSA Score Study
- 2017
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In: Stroke. - : Ovid Technologies (Wolters Kluwer Health). - 0039-2499 .- 1524-4628. ; 48:3, s. 726-732
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Journal article (peer-reviewed)abstract
- Background and Purposes-This study was designed to derive and validate a score to predict early ischemic events and major bleedings after an acute ischemic stroke in patients with atrial fibrillation. Methods-The derivation cohort consisted of 854 patients with acute ischemic stroke and atrial fibrillation included in prospective series between January 2012 and March 2014. Older age (hazard ratio 1.06 for each additional year; 95% confidence interval, 1.00-1.11) and severe atrial enlargement (hazard ratio, 2.05; 95% confidence interval, 1.08-2.87) were predictors for ischemic outcome events (stroke, transient ischemic attack, and systemic embolism) at 90 days from acute stroke. Small lesions (1.5 cm) were inversely correlated with both major bleeding (hazard ratio, 0.39; P=0.03) and ischemic outcome events (hazard ratio, 0.55; 95% confidence interval, 0.30-1.00). We assigned to age 80 years 2 points and between 70 and 79 years 1 point; ischemic index lesion >1.5 cm, 1 point; severe atrial enlargement, 1 point (ALESSA score). A logistic regression with the receiver-operating characteristic graph procedure (C statistic) showed an area under the curve of 0.697 (0.632-0.763; P=0.0001) for ischemic outcome events and 0.585 (0.493-0.678; P=0.10) for major bleedings. Results-The validation cohort consisted of 994 patients included in prospective series between April 2014 and June 2016. Logistic regression with the receiver-operating characteristic graph procedure showed an area under the curve of 0.646 (0.529-0.763; P=0.009) for ischemic outcome events and 0.407 (0.275-0.540; P=0.14) for hemorrhagic outcome events. Conclusions-In acute stroke patients with atrial fibrillation, high ALESSA scores were associated with a high risk of ischemic events but not of major bleedings.
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| 6. |
- Paciaroni, M., et al.
(author)
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Early Recurrence and Major Bleeding in Patients With Acute Ischemic Stroke and Atrial Fibrillation Treated With Non-Vitamin-K Oral Anticoagulants (RAF-NOACs) Study
- 2017
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In: Journal of the American Heart Association. - : Ovid Technologies (Wolters Kluwer Health). - 2047-9980. ; 6:12
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Journal article (peer-reviewed)abstract
- Background-The optimal timing to administer non-vitamin K oral anticoagulants (NOACs) in patients with acute ischemic stroke and atrial fibrillation is unclear. This prospective observational multicenter study evaluated the rates of early recurrence and major bleeding (within 90 days) and theirtiming in patients with acute ischemic stroke and atrial fibrillation who received NOACs for secondary prevention. Methods and Results-Recurrence was defined as the composite of ischemic stroke, transient ischemic attack, and symptomatic systemic embolism, and major bleeding was defined as symptomatic cerebral and major extracranial bleeding. For the analysis, 1127 patients were eligible: 381 (33.8%) were treated with dabigatran, 366 (32.5%) with rivaroxaban, and 380 (33.7%) with apixaban. Patients who received dabigatran were younger and had lower admission National Institutes of Health Stroke Scale score and less commonly had a CHA(2)DS(2)-VASc score >4 and less reduced renal function. Thirty-two patients (2.8%) had early recurrence, and 27 (2.4%) had major bleeding. The rates of early recurrence and major bleeding were, respectively, 1.8% and 0.5% in patients receiving dabigatran, 1.6% and 2.5% in those receiving rivaroxaban, and 4.0% and 2.9% in those receiving apixaban. Patients who initiated NOACs within 2 days after acute stroke had a composite rate of recurrence and major bleeding of 12.4%; composite rates were 2.1% for those who initiated NOACs between 3 and 14 days and 9.1% for those who initiated > 14 days after acute stroke. Conclusions-In patients with acute ischemic stroke and atrial fibrillation, treatment with NOACs was associated with a combined 5% rate of ischemic embolic recurrence and severe bleeding within 90 days.
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| 7. |
- Paradela, C., et al.
(author)
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High accuracy 235U(n,f) data in the resonance energy region
- 2016
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In: EPJ Web of Conferences. - : EDP Sciences. - 2100-014X.
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Conference paper (peer-reviewed)abstract
- The U-235 neutron-induced cross section is widely used as reference cross section for measuring other fission cross sections, but in the resonance region it is not considered as an IAEA standard because of the scarce experimental data covering the full region. In this work, we deal with a new analysis of the experimental data obtained with a detection setup based on parallel plate ionization chambers (PPACs) at the CERN n_TOF facility in the range from 1 eV to 10 keV. The relative cross section has been normalised to the IAEA value in the region between 7.8 and 11 eV, which is claimed as well-known. Comparison with the ENDF/B-VII evaluation and the IAEA reference file from 100 eV to 10 keV are provided.
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| 8. |
- Acciarresi, M., et al.
(author)
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Prestroke CHA(2)DS(2)-VASc Score and Severity of Acute Stroke in Patients with Atrial Fibrillation: Findings from RAF Study
- 2017
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In: Journal of Stroke & Cerebrovascular Diseases. - : Elsevier BV. - 1052-3057. ; 26:6, s. 1363-1368
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Journal article (peer-reviewed)abstract
- Background and Purpose: The aim of this study was to investigate for a possible association between both prestroke CHA(2)DS(2)-VASc score and the severity of stroke at presentation, as well as disability and mortality at 90 days, in patients with acute stroke and atrial fibrillation (AF). Methods: This prospective study enrolled consecutive patients with acute ischemic stroke, AF, and assessment of prestroke CHA2DS2-VASc score. Severity of stroke was assessed on admission using the National Institutes of Health Stroke Scale (NIHSS) score (severe stroke: NIHSS >= 10). Disability and mortality at 90 days were assessed by the modified Rankin Scale (mRS < 3 or >= 3). Multiple logistic regression was used to correlate prestroke CHA(2)DS(2)-VASc and severity of stroke, as well as disability and mortality at 90 days. Results: Of the 1020 patients included in the analysis, 606 patients had an admission NIHSS score lower and 414 patients higher than 10. At 90 days, 510 patients had mRS >= 3. A linear correlation was found between the prestroke CHA(2)DS(2)-VASc score and severity of stroke (P = .001). On multivariate analysis, CHA(2)DS(2)-VASc score correlated with severity of stroke (P = .041) and adverse functional outcome (mRS = 3) (P = .001). A logistic regression with the receiver operating characteristic graph procedure (C-statistics) evidenced an area under the curve of .60 (P = .0001) for severe stroke. Furthermore, a correlation was found between prestroke CHA(2)DS(2)-VASc score and lesion size. Conclusions: In patients with AF, in addition to the risk of stroke, a high CHA(2)DS(2)-VASc score was independently associated with both stroke severity at onset and disability and mortality at 90 days.
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| 9. |
- Kam, K., et al.
(author)
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Sleep oscillation-specific associations with Alzheimer's disease CSF biomarkers: novel roles for sleep spindles and tau
- 2019
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In: Molecular Neurodegeneration. - : Springer Science and Business Media LLC. - 1750-1326. ; 14
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Journal article (peer-reviewed)abstract
- BackgroundBased on associations between sleep spindles, cognition, and sleep-dependent memory processing, here we evaluated potential relationships between levels of CSF A(42), P-tau, and T-tau with sleep spindle density and other biophysical properties of sleep spindles in a sample of cognitively normal elderly individuals.MethodsOne-night in-lab nocturnal polysomnography (NPSG) and morning to early afternoon CSF collection were performed to measure CSF A(42), P-tau and T-tau. Seven days of actigraphy were collected to assess habitual total sleep time.ResultsSpindle density during NREM stage 2 (N2) sleep was negatively correlated with CSF A(42), P-tau and T-tau. From the three, CSF T-tau was the most significantly associated with spindle density, after adjusting for age, sex and ApoE4. Spindle duration, count and fast spindle density were also negatively correlated with T-tau levels. Sleep duration and other measures of sleep quality were not correlated with spindle characteristics and did not modify the associations between sleep spindle characteristics and the CSF biomarkers of AD.ConclusionsReduced spindles during N2 sleep may represent an early dysfunction related to tau, possibly reflecting axonal damage or altered neuronal tau secretion, rendering it a potentially novel biomarker for early neuronal dysfunction. Given their putative role in memory consolidation and neuroplasticity, sleep spindles may represent a mechanism by which tau impairs memory consolidation, as well as a possible target for therapeutic interventions in cognitive decline.
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| 10. |
- Varga, A. W., et al.
(author)
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Reduced Slow-Wave Sleep Is Associated with High Cerebrospinal Fluid A beta 42 Levels in Cognitively Normal Elderly
- 2016
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In: Sleep. - : Oxford University Press (OUP). - 0161-8105 .- 1550-9109. ; 39:11, s. 2041-2048
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Journal article (peer-reviewed)abstract
- Study Objectives: Emerging evidence suggests a role for sleep in contributing to the progression of Alzheimer disease (AD). Slow wave sleep (SWS) is the stage during which synaptic activity is minimal and clearance of neuronal metabolites is high, making it an ideal state to regulate levels of amyloid beta (A beta). We thus aimed to examine relationships between concentrations of A beta 42 in the cerebrospinal fluid (CSF) and measures of SWS in cognitively normal elderly subjects. Methods: Thirty-six subjects underwent a clinical and cognitive assessment, a structural MRI, a morning to early afternoon lumbar puncture, and nocturnal polysomnography. Correlations and linear regression analyses were used to assess for associations between CSF A beta 42 levels and measures of SWS controlling for potential confounders. Resulting models were compared to each other using ordinary least squared linear regression analysis. Additionally, the participant sample was dichotomized into "high" and "low" A beta 42 groups to compare SWS bout length using survival analyses. Results: A significant inverse correlation was found between CSF A beta 42 levels, SWS duration and other SWS characteristics. Collectively, total SWA in the frontal lead was the best predictor of reduced CSF A beta 42 levels when controlling for age and ApoE status. Total sleep time, time spent in NREM1, NREM2, or REM sleep were not correlated with CSF A beta 42. Conclusions: In cognitively normal elderly, reduced and fragmented SWS is associated with increases in CSF A beta 42, suggesting that disturbed sleep might drive an increase in soluble brain A beta levels prior to amyloid deposition.
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