| 2571. |
- Rubbia, C, et al.
(författare)
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Underground operation of the ICARUS T600 LAr-TPC : first results
- 2011
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Ingår i: Journal of Instrumentation. ; 6:07
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Tidskriftsartikel (refereegranskat)abstract
- Important open questions are still present in fundamental Physics and Cosmology, like the nature of Dark Matter, the matter-antimatter asymmetry and the validity of the Standard Model of particle interactions. Addressing these questions requires a new generation of massive particle detectors to explore the subatomic and astrophysical worlds. ICARUS T600 is the first large mass (760 tons) example of a new generation of detectors able to combine the imaging capabilities of the old famous “bubble chamber” with the excellent energy measurement of huge electronic detectors. ICARUS T600 now operates at the Gran Sasso underground laboratory and is used to study cosmic rays, neutrino oscillations and the proton decay. The potential for doing physics of this novel telescope is presented through a few examples of neutrino interactions reconstructed with unprecedented detail. Detector design and early operation are also reported.
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| 2572. |
- Rudy, Delaunay, et al.
(författare)
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Molecular growth inside polycyclic aromatic hydrocarbon clusters induced by ion collisions
- 2015
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Ingår i: Journal of Physical Chemistry Letters. - : American Chemical Society (ACS). - 1948-7185 .- 1948-7185. ; 6:9, s. 1536-1542
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Tidskriftsartikel (refereegranskat)abstract
- The present work combines experimental and theoretical studies of the collision between keV ion projectiles and clusters of pyrene, one of the simplest polycyclic aromatic hydrocarbons (PAHs). Intracluster growth processes induced by ion collisions lead to the formation of a wide range of new molecules with masses larger than that of the pyrene molecule. The efficiency of these processes is found to strongly depend on the mass and velocity of the incoming projectile. Classical molecular dynamics simulations of the entire collision process-from the ion impact (nuclear scattering) to the formation of new molecular species-reproduce the essential features of the measured molecular growth process and also yield estimates of the related absolute cross sections. More elaborate density functional tight binding calculations yield the same growth products as the classical simulations. The present results could be relevant to understand the physical chemistry of the PAH-rich upper atmosphere of Saturn’s moon Titan.
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| 2573. |
- Rushton, A. P., et al.
(författare)
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Resolved, expanding jets in the Galactic black hole candidate XTE J1908+094
- 2017
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Ingår i: Monthly Notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 468:3, s. 2788-2802
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Tidskriftsartikel (refereegranskat)abstract
- Black hole X-ray binaries undergo occasional outbursts caused by changing inner accretion flows. Here we report high angular resolution radio observations of the 2013 outburst of the black hole candidate X-ray binary system XTE J1908+094, using data from the Very Long Baseline Array and European VLBI Network. We show that following a hard-to-soft state transition, we detect moving jet knots that appear asymmetric in morphology and brightness, and expand to become laterally resolved as they move away from the core, along an axis aligned approximately -11. east of north. We initially see only the southern component, whose evolution gives rise to a 15-mJy radio flare and generates the observed radio polarization. This fades and becomes resolved out after 4 days, after which a second component appears to the north, moving in the opposite direction. From the timing of the appearance of the knots relative to the X-ray state transition, a 90. swing of the inferred magnetic field orientation, the asymmetric appearance of the knots, their complex and evolving morphology, and their low speeds, we interpret the knots as working surfaces where the jets impact the surrounding medium. This would imply a substantially denser environment surrounding XTE J1908+094 than has been inferred to exist around the microquasar sources GRS 1915+105 and GRO J1655-40.
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| 2574. |
- Ryder, JW, et al.
(författare)
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Use of a novel impermeable biotinylated photolabeling reagent to assess insulin- and hypoxia-stimulated cell surface GLUT4 content in skeletal muscle from type 2 diabetic patients
- 2000
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Ingår i: Diabetes. - : American Diabetes Association. - 0012-1797 .- 1939-327X. ; 49:4, s. 647-654
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Tidskriftsartikel (refereegranskat)abstract
- Cell surface GLUT4 levels in skeletal muscle from nine type 2 diabetic subjects and nine healthy control subjects have been assessed by a new technique that involves the use of a biotinylated photo-affinity label. A profound impairment in GLUT4 translocation to the skeletal muscle cell surface in response to insulin was observed in type 2 diabetic patients. Levels of insulin-stimulated cell surface GLUT4 above basal in type 2 diabetic patients were only approximately 10% of those observed in healthy subjects. The magnitude of the defect in GLUT4 translocation in type 2 diabetic patients was greater than that observed for glucose transport activity, which was approximately 50% of that in healthy subjects. Reduced GLUT4 translocation is therefore a major contributor to the impaired glucose transport activity in skeletal muscle from type 2 diabetic subjects. When a marked impairment in GLUT4 translocation occurs, the contribution of other transporters to transport activity becomes apparent. In response to hypoxia, marked reductions in skeletal muscle cell surface GLUT4 levels were also observed in type 2 diabetic patients. Therefore, a defect in a common late stage in signal transduction and/or a direct impairment in the GLUT4 translocation process accounts for reduced glucose transport in type 2 diabetic patients.
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| 2575. |
- Sacchet, Matthew D., et al.
(författare)
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Large-scale hypoconnectivity between resting-state functional networks in unmedicated adolescent major depressive disorder
- 2016
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Ingår i: Neuropsychopharmacology. - London : Nature Publishing Group. - 0893-133X .- 1740-634X. ; 41:12, s. 2951-2960
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Tidskriftsartikel (refereegranskat)abstract
- Major depressive disorder (MDD) often emerges during adolescence, a critical period of brain development. Recent resting-state fMRI studies of adults suggest that MDD is associated with abnormalities within and between resting-state networks (RSNs). Here we tested whether adolescent MDD is characterized by abnormalities in interactions among RSNs. Participants were 55 unmedicated adolescents diagnosed with MDD and 56 matched healthy controls. Functional connectivity was mapped using resting-state fMRI. We used the network-based statistic (NBS) to compare large-scale connectivity between groups and also compared the groups on graph metrics. We further assessed whether group differences identified using nodes defined from functionally defined RSNs were also evident when using anatomically defined nodes. In addition, we examined relations between network abnormalities and depression severity and duration. Finally, we compared intranetwork connectivity between groups and assessed the replication of previously reported MDD-related abnormalities in connectivity. The NBS indicated that, compared with controls, depressed adolescents exhibited reduced connectivity (p<0.024, corrected) between a specific set of RSNs, including components of the attention, central executive, salience, and default mode networks. The NBS did not identify group differences in network connectivity when using anatomically defined nodes. Longer duration of depression was significantly correlated with reduced connectivity in this set of network interactions (p=0.020, corrected), specifically with reduced connectivity between components of the dorsal attention network. The dorsal attention network was also characterized by reduced intranetwork connectivity in the MDD group. Finally, we replicated previously reported abnormal connectivity in individuals with MDD. In summary, adolescents with MDD show hypoconnectivity between large-scale brain networks compared with healthy controls. Given that connectivity among these networks typically increases during adolescent neurodevelopment, these results suggest that adolescent depression is associated with abnormalities in neural systems that are still developing during this critical period.
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| 2576. |
- Saeed, M, et al.
(författare)
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Age and founder effect of SOD1 A4V mutation causing ALS.
- 2009
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Ingår i: Neurology. - : American Academy of Neurology. - 0028-3878 .- 1526-632X. ; 72:19, s. 1634-1639
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The alanine to valine mutation at codon 4 (A4V) of SOD1 causes a rapidly progressive dominant form of amyotrophic lateral sclerosis (ALS) with exclusively lower motor neuron disease and is responsible for 50% of SOD1 mutations associated with familial ALS in North America. This mutation is rare in Europe. The authors investigated the origin (geographic and time) of the A4V mutation. METHODS: Several cohorts were genotyped: North American patients with confirmed A4V mutation (n = 54), Swedish (n = 3) and Italian (n = 6) A4V patients, patients with ALS with SOD1 non-A4V mutations (n = 66) and patients with sporadic ALS (n = 96), healthy white (n = 96), African American (n = 17), Chinese (n = 53), Amerindian (n = 11), and Hispanic (n = 12) subjects. High-throughput SNP genotyping was performed using Taqman assay in 384-well format. A novel biallelic CA repeat in exon 5 of SOD1, tightly linked to A4V, was genotyped on sequencing gels. Association statistics were estimated using Haploview. p Values less than 0.05 were considered significant. Age of A4V was estimated using a novel method based on r(2) degeneration with genetic distance and a Bayesian method incorporated in DMLE+. RESULTS: A single haplotype of 10 polymorphisms across a 5.86-cM region was associated with A4V (p = 3.0e-11) when white controls were used, suggesting a founder effect. The strength of association of this haplotype progressively decreased when African American, Chinese, Hispanic, and Amerindian subjects were used as controls. The associated European haplotype was different from the North American haplotype, indicating two founder effects for A4V (Amerindian and European). The estimated age of A4V with the r(2) degeneration method was 458 +/- 59 years (range 398-569) and in agreement with the Bayesian method (554-734 years with 80-90% posterior probability). CONCLUSIONS: North American SOD1 alanine to valine mutation at codon 4 descended from two founders (Amerindian and European) 400-500 years ago.
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| 2577. |
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| 2578. |
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| 2579. |
- Sand, U., et al.
(författare)
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Control of Gas Bubbles and Slag Layer in a Ladle Furnace by Electromagnetic Stirring
- 2009
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Ingår i: Iron & Steel Technology. - 1547-0423. ; 6:7, s. 49-59
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Tidskriftsartikel (refereegranskat)abstract
- A study was conducted to present the numerical model and simulation results of electromagnetic and gas stirring (EMGAS) and compare with that of a water model. The new features of EMGAS regarding the gas plume, stirring energy, velocity, and mixing time were introduced. Fluent© was employed to develop the numerical modeling of the system and model the melt, slag, and gaseous atmosphere in the ladle top was conducted using the Volume of Fluid (VOF) approach. The turbulence of the flow system was modeled using the Reynolds stresses model that accounted for six equations, including one for each Reynolds stress component and the turbulent dissipation equation. The water model investigations were based on visualization using an advanced video camera. The model cases were designed to be analogous with the corresponding simulated cases. The visualization investigations focused mainly on the flow pattern and the gas plume structure.
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| 2580. |
- Sand, U., et al.
(författare)
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Numerical and Experimental Study on Fluid Dynamic Features of Combined Gas and Electromagnetic Stirring in Ladle Furnace
- 2009
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Ingår i: Steel Research Int.. ; 80:6, s. 441-449
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Tidskriftsartikel (refereegranskat)abstract
- Basic fluid dynamic features of combined electromagnetic stirring, EMS, and gas stirring (EMGAS) have been studied In the present work. A transient and turbulent multiphase numerical flow model was built. Simulations of a real size ladle furnace were conducted for 7 cases, operating with and without combined stirring and varying the argon gas inlet plug position. The results of these simulations are compared considering melt velocity, melt turbulence, melt/slag-interface turbulence and dispersion of gas bubbles. An experimental water model was also built to simulate the effects of combined stirring. The water model was numerically simulated and visual comparison of the gas plume shape and flow pattern in the numerical and in the experimental model was also done for 3 flow situations. The results show that EMGAS has a strong flexibility regarding the flow velocity, gas plume, stirring energy, mixing time, slag layer, etc.
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