609 research outputs found

    Atherosclerotic carotid plaque composition: a 3T and 7T MRI-histology correlation study

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    Background and Purpose Carotid artery atherosclerotic plaque composition may influence plaque stability and risk of thromboembolic events, and non-invasive plaque imaging may therefore permit risk stratification for clinical management. Plaque composition was compared using non-invasive in-vivo (3T) and ex-vivo (7T) MRI and histopathological examination. Methods Thirty three endarterectomy cross sections, from 13 patients, were studied. The datasets consisted of in-vivo 3T MRI, ex-vivo 7T MRI and histopathology. Semi-automated segmentation methods were used to measure areas of different plaque components. Bland- Altman plots and mean difference with 95% confidence interval were carried out. Results There was general quantitative agreement between areas derived from semi-automated segmentation of MRI data and histology measurements. The mean differences and 95% confidence bounds in the relative to total plaque area between 3T versus Histology were: fibrous tissue 4.99 % (-4.56 to 14.56), lipid-rich/necrotic core (LR/NC) with haemorrhage - 1.81% (-14.11 to 10.48), LR/NC without haemorrhage -2.43% (-13.04 to 8.17), and calcification -3.18% (-11.55 to 5.18). The mean differences and 95% confidence bounds in the relative to total plaque area between 7T and histology were: fibrous tissue 3.17 % (-3.17 to 9.52), LR/NC with haemorrhage -0.55% (-9.06 to 7.95), LR/NC without haemorrhage - 12.62% (-19.8 to -5.45), and calcification -2.43% (-9.97 to 4.73). Conclusions This study provides evidence that semi-automated segmentation of 3T/7T MRI techniques can help to determine atherosclerotic plaque composition. In particular, the high resolution of ex-vivo 7T data was able to highlight greater detail in the atherosclerotic plaque composition. High field MRI may therefore have advantages for in vivo carotid plaque MR imaging

    Occurrence of methicillin-resistant Staphylococcus aureus in surface waters near industrial hog operation spray fields

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    Industrial hog operations (IHOs) have been identified as a source of antibiotic-resistant Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA). However, few studies have investigated the presence of antibiotic-resistant S. aureus in the environment near IHOs, specifically surface waters proximal to spray fields where IHO liquid lagoon waste is sprayed. Surface water samples (n = 179) were collected over the course of approximately one year from nine locations in southeastern North Carolina and analyzed for the presence of presumptive MRSA using CHROMagar MRSA media. Culture-based, biochemical, and molecular tests, as well as matrix-assisted laser desorption/ionization-time of flight mass spectrometry were used to confirm that isolates that grew on CHROMagar MRSA media were S. aureus. Confirmed S. aureus isolates were then tested for susceptibility to 16 antibiotics and screened for molecular markers of MRSA (mecA, mecC) and livestock adaptation (absence of scn). A total of 12 confirmed MRSA were detected in 9 distinct water samples. Nine of 12 MRSA isolates were also multidrug-resistant (MDRSA [i.e., resistant to ≥ 3 antibiotic classes]). All MRSA were scn-positive and most (11/12) belonged to a staphylococcal protein A (spa) type t008, which is commonly associated with humans. Additionally, 12 confirmed S. aureus that were methicillin-susceptible (MSSA) were recovered, 7 of which belonged to spa type t021 and were scn-negative (a marker of livestock-adaptation). This study demonstrated the presence of MSSA, MRSA, and MDRSA in surface waters adjacent to IHO lagoon waste spray fields in southeastern North Carolina. To our knowledge, this is the first report of waterborne S. aureus from surface waters proximal to IHOs

    Self-Reported Truck Traffic on the Street of Residence and Symptoms of Asthma and Allergic Disease: A Global Relationship in ISAAC Phase 3

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    BACKGROUND: Associations between traffic pollution on the street of residence and a range of respiratory and allergic outcomes in children have been reported in developed countries, but little is known about such associations in developing countries. METHODS: The third phase of the International Study of Asthma and Allergies in Childhood (ISAAC) was carried out in 13- to 14-year-old and 6- to 7-year-old children across the world. A question about frequency of truck traffic on the street of residence was included in an additional questionnaire. We investigated the association between self-reported truck traffic on the street of residence and symptoms of asthma, rhinoconjunctivitis, and eczema with logistic regression. Adjustments were made for sex, region of the world, language, gross national income, and 10 other subject-specific covariates. RESULTS: Frequency of truck traffic on the street of residence was positively associated with the prevalence of symptoms of asthma, rhinoconjunctivitis, and eczema with an exposure-response relationship. Odds ratios (95% confidence intervals) for "current wheeze" and "almost the whole day" versus "never" truck traffic were 1.35 (1.23-1.49) for 13- to 14-year-olds and 1.35 (1.22-1.48) for 6- to 7-year-olds. CONCLUSIONS: Higher exposure to self-reported truck traffic on the street of residence is associated with increased reports of symptoms of asthma, rhinitis, and eczema in many locations in the world. These findings require further investigation in view of increasing exposure of the world's children to traffic

    Testing factorization in B -> D(*)X decays

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    In QCD the amplitude for B0 -> D(*)+pi- factorizes in the large Nc limit or in the large energy limit Q >> Lambda_QCD where Q = {m_b, m_c, m_b-m_c}. Data also suggests factorization in exclusive processes B-> D* pi+ pi- pi- pi0 and B-> D* omega pi-, however by themselves neither large Nc nor large Q can account for this. Noting that the condition for large energy release in B0-> D+ pi- is enforced by the SV limit, m_b, m_c >> m_b-m_c >> Lambda, we propose that the combined large Nc and SV limits justify factorization in B -> D(*) X. This combined limit is tested with the inclusive decay spectrum measured by CLEO. We also give exact large Nc relations among isospin amplitudes for B -> D(*)X and B -> D(*) D-bar(*)X, which can be used to test factorization through exclusive or inclusive measurements. Predictions for the modes B-> D(*) pi pi, B-> D(*)K K-bar and B-> D(*) D-bar(*) K are discussed using available data.Comment: 15 pages, 3 included .eps figures, minor change

    Improving distribution network model accuracy using impedance estimation from micro-synchrophasor data

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    An accurate network model is essential for performing detailed analysis of a power system. The quality of many distribution network models is very diverse, especially for low voltage (LV) networks. To help identify areas where the model is incomplete or incorrect, Micro Phasor Measurement Units (μPMUs) can be integrated into a network. These μPMUs would work together, with a trusted cloud back-end system. The basis for this paper is to determine how the data collected by μPMUs can be used, and what can be calculated from this data to help recognize areas where the network model is inaccurate and may need resurveyed. As a preliminary investigation to determine the feasibility of the approach, this paper discusses the calculation of the impedance of both a transformer and line, and compares the values obtained from μPMU data to the level of value expected on the network

    DNA single-strand break repair and spinocerebellar ataxia with axonal neuropathy-1

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    DNA single-strand breaks (SSBs) are the commonest DNA lesions arising spontaneously in cells, and if not repaired may block transcription or may be converted into potentially lethal/clastogenic DNA double-strand breaks (DSBs). Recently, evidence has emerged that defects in the rapid repair of SSBs preferentially impact the nervous system. In particular, spinocerebellar ataxia with axonal neuropathy (SCAN1) is a human disease that is associated with mutation of TDP1 (tyrosyl DNA phosphodiesterase 1) protein and with a defect in repairing certain types of SSBs. Although SCAN1 is a rare neurodegenerative disorder, understanding the molecular basis of this disease will lead to better understanding of neurodegenerative processes. Here we review recent progress in our understanding of TDP1, single-strand break repair (SSBR), and neurodegenerative disease

    Increasing the speed of automated ultrasonic inspection of as-built additive manufacturing components by the adoption of virtual source aperture

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    Wire + Arc Additive Manufacture (WAAM) is an economical manufacturing technique to build components. To maintain the commercial and technical benefits, inspection is desired at each layer of the build. New conformable phased array roller-probes offer the potential to inspect the as-built sample in-process or on completion. A challenge with such inspections is the refraction of the ultrasonic waves at multiple interfaces. The Synthetic Aperture Focusing Technique (SAFT) and Total Focusing Method (TFM), combined with Full Matrix Capture (FMC) acquisition enabled imaging through the as-built WAAM surface. However, single-element firings, associated with FMC are a limiting factor due to the lower energy at transmission, while the high number of firings and subsequent larger data size negatively affect inspection speed. This work introduces the concept of Virtual Source Aperture (VSA) for ultrasonic roller-probe inspection, through modelling of VSA on custom-designed calibration WAAM block. The concept is then demonstrated on a mock as-built WAAM sample inspection with reference defects. The results demonstrate that a markedly lower number of transmissions are required to match the performance of the FMC counterpart while increasing the energy levels. Moreover, an almost 50% reduction in the data size enabled a doubling of the inspection speed

    The Mw 5.1, 9 August 2020, Sparta Earthquake, North Carolina: The First Documented Seismic Surface Rupture in the Eastern United States

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    At 8:07 a.m. EDT on 9 Aug. 2020 a Mw 5.1 earthquake located ~3 km south of Sparta, North Carolina, USA, shook much of the eastern United States, producing the first documented surface rupture due to faulting east of the New Madrid seismic zone. The co-seismic surface rupture was identified along a 2-km-long traceable zone of predominantly reverse displacement, with folding and flexure generating a scarp averaging 8–10-cm-high with a maximum observed height of ~25 cm. Widespread deformation south of the main surface rupture includes cm-dm–long and mm-cm–wide fissures. Two trenches excavated across the surface rupture reveal that this earthquake propagated to the surface along a preexisting structure in the shallow bedrock, which had not been previously identified as an active fault. Surface ruptures by faulting are rarely reported for M <6 earthquakes, and hence the Sparta earthquake provides an opportunity to improve seismic hazard knowledge associated with these moderate events. Furthermore, this earthquake occurred in a very low strain rate intraplate setting, where earthquake surface deformation, regardless of magnitude, is sparse in time and rare to observe and characterize

    Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

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    A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results
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