201 research outputs found

    Effects of bronchodilators on dynamic hyperinflation following hyperventilation in patients with COPD

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    ‘The definitive version is available at www.blackwell-synergy.com '.ArticleRespirology. 12(1): 93-99 (2007)journal articl

    Molecular Clouds associated with the Type Ia SNR N103B in the Large Magellanic Cloud

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    N103B is a Type Ia supernova remnant (SNR) in the Large Magellanic Cloud (LMC). We carried out new 12^{12}CO(JJ = 3-2) and 12^{12}CO(JJ = 1-0) observations using ASTE and ALMA. We have confirmed the existence of a giant molecular cloud (GMC) at VLSRV_\mathrm{LSR} \sim245 km s1^{-1} towards the southeast of the SNR using ASTE 12^{12}CO(JJ = 3-2) data at an angular resolution of \sim25"" (\sim6 pc in the LMC). Using the ALMA 12^{12}CO(JJ = 1-0) data, we have spatially resolved CO clouds along the southeastern edge of the SNR with an angular resolution of \sim1.8"" (\sim0.4 pc in the LMC). The molecular clouds show an expanding gas motion in the position-velocity diagram with an expansion velocity of 5\sim5 km s1^{-1}. The spatial extent of the expanding shell is roughly similar to that of the SNR. We also find tiny molecular clumps in the directions of optical nebula knots. We present a possible scenario that N103B exploded in the wind-bubble formed by the accretion winds from the progenitor system, and is now interacting with the dense gas wall. This is consistent with a single-degenerate scenario.Comment: 12 pages, 1 table, 8 figures, accepted for publication in The Astrophysical Journal (ApJ

    Discovery of possible molecular counterparts to the infrared Double Helix Nebula in the Galactic center

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    We have discovered two molecular features at radial velocities of -35 km/s and 0 km/s toward the infrared Double Helix Nebula (DHN) in the Galactic center with NANTEN2. The two features show good spatial correspondence with the DHN. We have also found two elongated molecular ridges at these two velocities distributed vertically to the Galactic plane over 0.8 degree. The two ridges are linked by broad features in velocity and are likely connected physically with each other. The ratio between the 12CO J=2-1 and J=1-0 transitions is 0.8 in the ridges which is larger than the average value 0.5 in the foreground gas, suggesting the two ridges are in the Galactic center. An examination of the K band extinction reveals a good coincidence with the CO 0 km/s ridge and is consistent with a distance of 8 +/-2 kpc. We discuss the possibility that the DHN was created by a magnetic phenomenon incorporating torsional Alfv\'en waves launched from the circumnuclear disk (Morris, Uchida & Do 2006) and present a first estimate of the mass and energy involved in the DHN.Comment: 32 pages, 23 figures, Accepted by Ap

    ALMA CO Observations of Supernova Remnant N63A in the Large Magellanic Cloud: Discovery of Dense Molecular Clouds Embedded within Shock-Ionized and Photoionized Nebulae

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    We carried out new 12^{12}CO(JJ = 1-0, 3-2) observations of a N63A supernova remnant (SNR) from the LMC using ALMA and ASTE. We find three giant molecular clouds toward the northeast, east, and near the center of the SNR. Using the ALMA data, we spatially resolved clumpy molecular clouds embedded within the optical nebulae in both the shock-ionized and photoionized lobes discovered by previous Hα\alpha and [S II] observations. The total mass of the molecular clouds is \sim800800 MM_{\odot} for the shock-ionized region and \sim17001700 MM_{\odot} for the photoionized region. Spatially resolved X-ray spectroscopy reveals that the absorbing column densities toward the molecular clouds are \sim1.51.5-6.0×10216.0\times10^{21} cm2^{-2}, which are \sim1.51.5-1515 times less than the averaged interstellar proton column densities for each region. This means that the X-rays are produced not only behind the molecular clouds, but also in front of them. We conclude that the dense molecular clouds have been completely engulfed by the shock waves, but have still survived erosion owing to their high-density and short interacting time. The X-ray spectrum toward the gas clumps is well explained by an absorbed power-law or high-temperature plasma models in addition to the thermal plasma components, implying that the shock-cloud interaction is efficiently working for both the cases through the shock ionization and magnetic field amplification. If the hadronic gamma-ray is dominant in the GeV band, the total energy of cosmic-ray protons is calculated to be \sim0.30.3-1.4×10491.4\times10^{49} erg with the estimated ISM proton density of \sim190±90190\pm90 cm3^{-3}, containing both the shock-ionized gas and neutral atomic hydrogen.Comment: 18 pages, 4 tables, 8 figures, accepted for publication in The Astrophysical Journal (ApJ

    Toxic tau oligomer formation blocked by capping of cysteine residues with 1,2-dihydroxybenzene groups

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    Neurofibrillary tangles, composed of hyperphosphorylated tau fibrils, are a pathological hallmark of Alzheimer's disease; the neurofibrillary tangle load correlates strongly with clinical progression of the disease. A growing body of evidence indicates that tau oligomer formation precedes the appearance of neurofibrillary tangles and contributes to neuronal loss. Here we show that tau oligomer formation can be inhibited by compounds whose chemical backbone includes 1,2-dihydroxybenzene. Specifically, we demonstrate that 1,2-dihydroxybenzene-containing compounds bind to and cap cysteine residues of tau and prevent its aggregation by hindering interactions between tau molecules. Further, we show that orally administered DL-isoproterenol, an adrenergic receptor agonist whose skeleton includes 1,2-dihydroxybenzene and which penetrates the brain, reduces the levels of detergent-insoluble tau, neuronal loss and reverses neurofibrillary tangle-associated brain dysfunction. Thus, compounds that target the cysteine residues of tau may prove useful in halting the progression of Alzheimer's disease and other tauopathies
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