289 research outputs found
MR coil sensitivity inhomogeneity correction for plaque characterization in carotid arteries
We are involved in a comprehensive program to characterize atherosclerotic disease using multiple MR images having different contrast mechanisms (T1W, T2W, PDW, magnetization transfer, etc.) of human carotid and animal model arteries. We use specially designed intravascular and surface array coils that give high signal-to-noise but suffer from sensitivity inhomogeneity. With carotid surface coils, challenges include: (1) a steep bias field with an 80% change; (2) presence of nearby muscular structures lacking high frequency information to distinguish bias from anatomical features; (3) many confounding zero-valued voxels subject to fat suppression, blood flow cancellation, or air, which are not subject to coil sensitivity; and (4) substantial noise. Bias was corrected using a modification of the adaptive fuzzy c-mean method reported by Pham et al. (IEEE TMI, 18:738-752), whereby a bias field modeled as a mechanical membrane was iteratively improved until cluster means no longer changed. Because our images were noisy, we added a noise reduction filtering step between iterations and used approximate to5 classes. In a digital phantom having a bias field measured from our MR system, variations across an area comparable to a carotid artery were reduced from 50% t
EUROnu-WP6 2010 Report
This is a summary of the work done by the Working Package 6 (Physics) of the
EU project "EUROnu" during the second year of activity of the project.Comment: 82 pages, 51 eps figure
Comparative Analysis of Different Definitions of Amyloid-beta Positivity to Detect Early Downstream Pathophysiological Alterations in Preclinical Alzheimer
Amyloid-ÎČ (AÎČ) positivity is defined using different biomarkers and different criteria. Criteria used in symptomatic patients may conceal meaningful early AÎČ pathology in preclinical Alzheimer. Therefore, the description of sensitive cutoffs to study the pathophysiological changes in early stages of the Alzheimerâs continuum is critical. Here, we compare different AÎČ classification approaches and we show their performance in detecting pathophysiological changes downstream AÎČ pathology. We studied 368 cognitively unimpaired individuals of the ALFA+ study, many of whom in the preclinical stage of the Alzheimerâs continuum. Participants underwent AÎČ PET and CSF biomarkers assessment. We classified participants as AÎČ -positive using five approaches: (1) CSF AÎČ42 12; (4) AÎČ PET Centiloid > 30 or (5) AÎČ PET Positive visual read. We assessed the correlations between AÎČ biomarkers and compared the prevalence of AÎČ positivity. We determined which approach significantly detected associations between AÎČ pathology and tau/neurodegeneration CSF biomarkers. We found that CSF-based approaches result in a higher AÎČ-positive prevalence than PET-based ones. There was a higher number of discordant participants classified as CSF AÎČ-positive but PET AÎČ-negative than CSF AÎČ-negative but PET AÎČ-positive. The CSF AÎČ 42/40 approach allowed optimal detection of significant associations with CSF p-tau and t-tau in the AÎČ-positive group. Altogether, we highlight the need for sensitive AÎČ -classifications to study the preclinical Alzheimerâs continuum. Approaches that define AÎČ positivity based on optimal discrimination of symptomatic Alzheimerâs disease patients may be suboptimal for the detection of early pathophysiological alterations in preclinical Alzheimer
American heart association's life simple 7 and the risk of atrial fibrillation in the PREDIMED study cohort
Background and aims
The American Heart Association proposed 7 ideal cardiovascular health metrics (Life's Simple 7 [LS7]) namely, not smoking, body mass index <25 kg/m2, healthy diet, moderate physical activity â„150 min/week, total blood cholesterol <200 mg/dL, blood pressure <120/80 mmHg and fasting blood glucose <100 mg/dL. Our objective was to assess the association between these LS7 metrics and the incidence of atrial fibrillation (AF).
Methods and results
A total of 6,479 participants of the PREDIMED study were included. We calculated the participantsâ baseline LS7 index ranging 0â7 points to categorize them according to their adherence to these LS7 health metrics. Multivariable Cox regression models were used to estimate Hazard Ratios (HR) and their 95% Confidence Intervals (95% CI). After a median follow-up of 4.8 years, we identified 250 incident cases of AF. After adjusting for potential confounders, adherence to LS7 index was not associated with the incidence of AF (adjusted HR 0.90 [95% CI: 0.56â1.45] for highest vs. lowest LS7 categories). Body mass index <25 kg/m2 was the only health metric individually associated with a lower risk of AF (HR 0.36 [95% CI: 0.16â0.78]).
Conclusions
In a high cardiovascular risk Spanish population, adherence to American Heart Association's LS7 metrics was not associated with the risk of incident AF
Mediterranean Diet and atherothrombosis biomarkers: a randomized controlled trial
Scope. To assess whether following a Mediterranean diet (MedDiet) improved
atherothrombosis biomarkers in high cardiovascular risk individuals.
Methods and results. In 358 random volunteers from the PREvenciĂłn con DIeta MEDiterrĂĄnea trial, we assessed the 1-year effects on atherothrombosis markers of an
intervention with MedDiet, enriched with virgin olive oil (MedDiet-VOO; n=120) or nuts
(MedDiet-Nuts; n=119) versus a low-fat control diet (n=119). We also studied whether large increments in MedDiet adherence (â„3 score points, relative to compliance
decreases) and intake changes in key food items were associated with 1-year differences
in biomarkers. We observed differences between 1-year changes in the MedDiet-VOO intervention and control diet on the activity of platelet activating factor acetylhydrolase in
HDLs (+7.5% [95% confidence interval: 0.17; 14.8]) and HDL-bound α1-antitrypsin levels (-
6.1% [-11.8; -0.29]), and between the MedDiet-Nuts intervention and the control arm on non-esterified fatty acid concentrations (-9.3% [-18.1; -0.53]). Large MedDiet adherence
increments were associated with less fibrinogen (-9.5% [-18.3; -0.60]) and non-esterified fatty acid concentrations (-16.7% [-31.7; -1.74]). Increases in nut, fruit, vegetable, and fatty
fish consumption, and decreases in processed meat intake were linked to beneficial changes in atherothrombosis biomarkers.
Conclusion. Following a MedDiet improved atherothrombosis biomarkers in high cardiovascular risk individual
High intensity neutrino oscillation facilities in Europe
The EUROnu project has studied three possible options for future, high intensity neutrino oscillation facilities in Europe. The first is a Super Beam, in which the neutrinos come from the decay of pions created by bombarding targets with a 4 MW proton beam from the CERN High Power Superconducting Proton Linac. The far detector for this facility is the 500 kt MEMPHYS water Cherenkov, located in the FrĂ©jus tunnel. The second facility is the Neutrino Factory, in which the neutrinos come from the decay of ÎŒ+ and ÎŒâ beams in a storage ring. The far detector in this case is a 100 kt magnetized iron neutrino detector at a baseline of 2000 km. The third option is a Beta Beam, in which the neutrinos come from the decay of beta emitting isotopes, in particular He6 and Ne18, also stored in a ring. The far detector is also the MEMPHYS detector in the FrĂ©jus tunnel. EUROnu has undertaken conceptual designs of these facilities and studied the performance of the detectors. Based on this, it has determined the physics reach of each facility, in particular for the measurement of CP violation in the lepton sector, and estimated the cost of construction. These have demonstrated that the best facility to build is the Neutrino Factory. However, if a powerful proton driver is constructed for another purpose or if the MEMPHYS detector is built for astroparticle physics, the Super Beam also becomes very attractive
Searches for sterile neutrinos with the IceCube detector
The IceCube neutrino telescope at the South Pole has measured the atmospheric muon neutrino spectrum as a function of zenith angle and energy in the approximate 320 GeV to 20 TeV range, to search for the oscillation signatures of light sterile neutrinos. No evidence for anomalous nu(mu) or (nu) over bar (mu) disappearance is observed in either of two independently developed analyses, each using one year of atmospheric neutrino data. New exclusion limits are placed on the parameter space of the 3 + 1 model, in which muon antineutrinos experience a strong Mikheyev-Smirnov-Wolfenstein-resonant oscillation. The exclusion limits extend to sin(2)2 theta(24) <= 0.02 at Delta m(2) similar to 0.3 eV(2) at the 90% confidence level. The allowed region from global analysis of appearance experiments, including LSND and MiniBooNE, is excluded at approximately the 99% confidence level for the global best-fit value of vertical bar U-e4 vertical bar(2)
Predicting Alzheimer disease with beta-amyloid imaging: results from the Australian imaging, biomarkers, and lifestyle study of ageing
Objective: Biomarkers for Alzheimer disease (AD) can detect the disease pathology in asymptomatic subjects and individuals with mild cognitive impairment (MCI), but their cognitive prognosis remains uncertain. We aimed to determine the prognostic value of ÎČ-amyloid imaging, alone and in combination with memory performance, hippocampal atrophy, and apolipoprotein E Δ4 status in nondemented, older individuals. Methods: A total of 183 healthy individuals (age = 72.0 ± 7.26 years) and 87 participants with MCI (age = 73.7 ± 8.27) in the Australian Imaging, Biomarkers, and Lifestyle study of ageing were studied. Clinical reclassification was performed after 3 years, blind to biomarker findings. ÎČ-Amyloid imaging was considered positive if the (11) C-Pittsburgh compound B cortical to reference ratio was â„1.5. Results: Thirteen percent of healthy persons progressed (15 to MCI, 8 to dementia), and 59% of the MCI cohort progressed to probable AD. Multivariate analysis showed ÎČ-amyloid imaging as the single variable most strongly associated with progression. Of combinations, subtle memory impairment (Z score = -0.5 to -1.5) with a positive amyloid scan was most strongly associated with progression in healthy individuals (odds ratio [OR] = 16, 95% confidence interval [CI] = 3.7-68; positive predictive value [PPV] = 50%, 95% CI = 19-81; negative predictive value [NPV] = 94%, 95% CI = 88-98). Almost all amnestic MCI subjects (Z score †-1.5) with a positive amyloid scan developed AD (OR = â; PPV = 86%, 95% CI = 72-95; NPV = 100%, 95% CI = 80-100). Hippocampal atrophy and Δ4 status did not add further predictive value. Interpretations: Subtle memory impairment with a positive ÎČ-amyloid scan identifies healthy individuals at high risk for MCI or AD. Clearly amnestic patients with a positive amyloid scan have prodromal AD and a poor prognosis for dementia within 3 years.Christopher C. Rowe, Pierrick Bourgeat, Kathryn A. Ellis, Belinda Brown, Yen Ying Lim, Rachel Mulligan, Gareth Jones, Paul Maruff, Michael Woodward, Roger Price, Peter Robins, Henri Tochon-Danguy, Graeme OâKeefe, Kerryn E. Pike, Paul Yates, Cassandra Szoeke, Olivier Salvado, S. Lance Macaulay, Timothy OâMeara, Richard Head, Lynne Cobiac, Greg Savage, Ralph Martins, Colin L. Masters, David Ames, and Victor L. Villemagn
Stormwater harvesting from landscaped areas:effect of herbicide application on water quality and usage
Diet and food strategies in a southern al-Andalusian urban environment during Caliphal period, ecija, Sevilla
The Iberian medieval period is unique in European history due to the widespread socio-cultural changes that took place after the
arrival of Arabs, Berbers and Islam in 711 AD. Recently, isotopic research has been insightful on dietary shifts, status, resource
availability and the impact of environment. However, there is no published isotopic research exploring these factors in southern
Iberian populations, and as the history of this area differs to the northern regions, this leaves a significant lacuna in our
knowledge. This research fills this gap via isotopic analysis of human (n = 66) and faunal (n = 13) samples from the 9th to the
13th century Ăcija, a town renowned for high temperatures and salinity. Stable carbon (ÎŽ13C) and nitrogen (ÎŽ15N) isotopes were
assessed from rib collagen, while carbon (ÎŽ13C) values were derived from enamel apatite. Human diet is consistent with C3 plant
consumption with a very minor contribution of C4 plants, an interesting feature considering the suitability of Ăcija to C4 cereal
production. ÎŽ15N values vary among adults, which may suggest variable animal protein consumption or isotopic variation within
animal species due to differences in foddering. Consideration of ÎŽ13C collagen and apatite values together may indicate sugarcane
consumption, while moderate ÎŽ15N values do not suggest a strong aridity or salinity effect. Comparison with other Iberian groups
shows similarities relating to time and location rather than by religion, although more multi-isotopic studies combined with
zooarchaeology and botany may reveal subtle differences unobservable in carbon and nitrogen collagen studies alone.OLC is funded by Plan Galego I2C mod.B (ED481D 2017/014). The research was partially funded by the projects âGalician Paleodietâ and by Consiliencia network (ED 431D2017/08) Xunta de GaliciaS
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