26 research outputs found
A Galaxy-scale Fountain of Cold Molecular Gas Pumped by a Black Hole
We present Atacama Large Millimeter/submillimeter Array and Multi-Unit Spectroscopic Explorer observations of the brightest cluster galaxy in Abell 2597, a nearby (z = 0.0821) cool core cluster of galaxies. The data map the kinematics of a three billion solar mass filamentary nebula that spans the innermost 30 kpc of the galaxy's core. Its warm ionized and cold molecular components are both cospatial and comoving, consistent with the hypothesis that the optical nebula traces the warm envelopes of many cold molecular clouds that drift in the velocity field of the hot X-ray atmosphere. The clouds are not in dynamical equilibrium, and instead show evidence for inflow toward the central supermassive black hole, outflow along the jets it launches, and uplift by the buoyant hot bubbles those jets inflate. The entire scenario is therefore consistent with a galaxy-spanning "fountain," wherein cold gas clouds drain into the black hole accretion reservoir, powering jets and bubbles that uplift a cooling plume of low-entropy multiphase gas, which may stimulate additional cooling and accretion as part of a self-regulating feedback loop. All velocities are below the escape speed from the galaxy, and so these clouds should rain back toward the galaxy center from which they came, keeping the fountain long lived. The data are consistent with major predictions of chaotic cold accretion, precipitation, and stimulated feedback models, and may trace processes fundamental to galaxy evolution at effectively all mass scales
A galaxy-scale fountain of cold molecular gas pumped by a black hole
We present ALMA and MUSE observations of the Brightest Cluster Galaxy in Abell 2597, a nearby (z = 0:0821) cool core cluster of galaxies. The data map the kinematics of a three billion solar mass filamentary nebula that spans the innermost 30 kpc of the galaxyâs core. Its warm ionized and cold molecular components are both cospatial and comoving, consistent with the hypothesis that the optical nebula traces the warm envelopes of many cold molecular clouds that drift in the velocity field of the hot X-ray atmosphere. The clouds are not in dynamical equilibrium, and instead show evidence for inflow toward the central supermassive black hole, outflow along the jets it launches, and uplift by the buoyant hot bubbles those jets inflate. The entire scenario is therefore consistent with a galaxy-spanning âfountainâ, wherein cold gas clouds drain into the black hole accretion reservoir, powering jets and bubbles that uplift a cooling plume of low-entropy multiphase gas, which may stimulate additional cooling and accretion as part of a self-regulating feedback loop. All velocities are below the escape speed from the galaxy, and so these clouds should rain back toward the galaxy center from which they came, keeping the fountain long-lived. The data are consistent with major predictions of chaotic cold accretion, precipitation, and stimulated feedback models, and may trace processes fundamental to galaxy evolution at effectively all mass scale
Effect of Erbium:yttrium aluminum garnet laser on bond strength of a total-etch adhesive system to caries-affected dentin on gingival wall
Purpose: To assess the effect of the erbium:yttrium aluminum garnet (Er:YAG) laser on bond strength of a totalâetch adhesive system to the cariesâaffected dentin on the gingival wall.Materials and Methods: Ten human molars with proximal carious lesions were randomly divided into two groups. In the first group, the carious dentin was removed with a bur, whereas in the second group it was removed with the Er:YAG laser. Carious lesions were excavated with one of these two techniques until laser fluorescence values decreased to 15 in the center of the lesions. The teeth were then restored with a totalâetch adhesive system (Adper Single Bond 2) and composite resin (Filtek Z250). Five teeth from each group were sectioned to obtain 1 mm2 stickâshaped microtensile specimens from each tooth. Twentyâfive specimens were obtained for each group with using this technique. The data were analyzed in independentâsamples tâtest (α = 0.05). For each removal technique, one sample was analyzed using scanning electron microscopy.Results: No statistically significant differences were found between the bond strength of the Er:YAG laser and the burâtreated groups (P > 0.05).Conclusion: The Er:YAG laser treatment did not negatively affect the bonding performance of the totalâetch adhesive system to cariesâaffected dentin on the gingival wall.Keywords: Bond strength, bur, caries removing, dentin, erbium:yttrium aluminum garnet laser, gingival wal
Physical, morphological properties and raman spectroscopy of chestnut blight diseased Castanea sativa Mill. Wood [Propriedades fĂsicas e morfolĂłgicas e espectroscopia raman de madeira de Castanea sativa Mill. Afetada pelo cancro do castanheiro]
In this study, some of the physical and anatomical properties of Chestnut Blight Diseased (CBD) wood were investigated, and the study also included observations using Raman spectroscopy. The objective of these investigations was to determine the extent of the damage that is done to the wood of the diseased chestnut trees, which must be removed from the forest and used in the manufacture of industrial products. It was indicated that most of the adverse effects of the disease were in the vascular cambium. There was a clear indication of deterioration of the wood in the last growth ring next to vascular cambium. In the diseased secondary xylem region next to vascular cambium; vessel diameter, vessel frequency and vessel element length had a decrease, and vessel and other cells were irregular compared to healthy wood. Spores were detected and identified as Cryphonectria parasitica (Murrill). Annual ring properties (annual growth ring width, latewood percentage, etc.) were similar in diseased wood compared to healthy wood. The Raman spectroscopy results showed no significant changes in the structure of the cell wall or its components. After removing the diseased parts, unlimited usage of formerly wood is possible. Heat treatment of the wood is suggested before use in the interest of sanitation and dimensional stability. © 2016, Federal University of Lavras. All rights reserved
Left ventricular mechanics after arterial switch operation: A speckle-Tracking echocardiography study
The arterial switch operation (ASO) is nowadays the standard procedure for the repair of dextro-transposition of the great arteries (d-TGA). Reduced exercise capacity, coronary artery abnormalities, and reversible myocardial perfusion defects have been demonstrated in patients who have undergone ASO. Despite this, indices of systolic function, assessed by standard echocardiography, are within the normal range. Speckle-tracking echocardiography (STE) can detect early subclinical myocardial abnormalities in several diseases even in the presence of normal left ventricular (LV) ejection fraction.Background The arterial switch operation (ASO) is nowadays the standard procedure for the repair of dextro-Transposition of the great arteries (d-TGA). Reduced exercise capacity, coronary artery abnormalities, and reversible myocardial perfusion defects have been demonstrated in patients who have undergone ASO. Despite this, indices of systolic function, assessed by standard echocardiography, are within the normal range. Speckle-Tracking echocardiography (STE) can detect early subclinical myocardial abnormalities in several diseases even in the presence of normal left ventricular (LV) ejection fraction. Aim To assess LV systolic myocardial deformation and torsion in asymptomatic ASO patients with normal LV ejection fraction (â„55%) by using STE. Methods We studied 62 asymptomatic patients (26 women) who have undergone single-stage ASO for simple d-TGA, aged 8.5±5.7 years, with a normal LV ejection fraction (â„55%); 31 age and sex comparable controls (14 women), aged 7.9±4.9 years. Results In patients who have undergone ASO, global LV longitudinal strain was significantly lower than that in controls (-19.2±2.9% vs.-22.7±2.4%, respectively, P<0.0001). Longitudinal deformation was significantly impaired in the anterior and both anterior and posterior septal walls. In patients who have undergone ASO global circumferential strain and LV torsion were similar to controls. At multivariate analysis global LV longitudinal strain was significantly correlated only with age at surgery (P=0.005). Conclusion We demonstrated a significant reduction in longitudinal myocardial deformation correlated with the age at surgical repair, despite a normal LV ejection fraction, in the largest series of asymptomatic ASO patients by using STE. Our findings suggest early (â€7 days) operation on d-TGA patients and continued monitoring of ventricular function by STE