2,192 research outputs found

    Sulphur monoxide exposes a potential molecular disk wind from the planet-hosting disk around HD100546

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    Sulphur-bearing volatiles are observed to be significantly depleted in interstellar and circumstellar regions. This missing sulphur is postulated to be mostly locked up in refractory form. With ALMA we have detected sulphur monoxide (SO), a known shock tracer, in the HD 100546 protoplanetary disk. Two rotational transitions: J=7ā‚‡-6ā‚† (301.286 GHz) and J=7ā‚ˆ-6ā‚‡ (304.078 GHz) are detected in their respective integrated intensity maps. The stacking of these transitions results in a clear 5Ļƒ detection in the stacked line profile. The emission is compact but is spectrally resolved and the line profile has two components. One component peaks at the source velocity and the other is blue-shifted by 5 km sā€¾Ā¹. The kinematics and spatial distribution of the SO emission are not consistent with that expected from a purely Keplerian disk. We detect additional blue-shifted emission that we attribute to a disk wind. The disk component was simulated using LIME and a physical disk structure. The disk emission is asymmetric and best fit by a wedge of emission in the north east region of the disk coincident with a `hot-spot' observed in the CO J=3-2 line. The favoured hypothesis is that a possible inner disk warp (seen in CO emission) directly exposes the north-east side of the disk to heating by the central star, creating locally the conditions to launch a disk wind. Chemical models of a disk wind will help to elucidate why the wind is particularly highlighted in SO emission and whether a refractory source of sulphur is needed. An alternative explanation is that the SO is tracing an accretion shock from a circumplanetary disk associated with the proposed protoplanet embedded in the disk at 50 au. We also report a non-detection of SO in the protoplanetary disk around HD 97048

    An introduction to clinical transplantation

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    First detections of HĀ¹Ā³CO+ and HCĀ¹āµN in the disk around HD 97048: Evidence for a cold gas reservoir in the outer disk

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    Observations of different molecular lines in protoplanetary disks provide valuable information on the gas kinematics, as well as constraints on the radial density and temperature structure of the gas. With ALMA we have detected HĀ¹Ā³CO+ (J = 4ā€“3) and HCĀ¹āµ N (J = 4ā€“3) in the HD 97048 protoplanetary disk for the first time. We compare these new detections to the ringed continuum mm-dust emission and the spatially resolved CO (J = 3ā€“2) and HCO+ (J = 4ā€“3) emission. The radial distributions of the HĀ¹Ā²CO+ and HCĀ¹āµN emission show hints of ringed sub-structure whereas, the optically thick tracers, CO and HCO+, do not. We calculate the HCO+/HĀ¹Ā³CO+ intensity ratio across the disk and find that it is radially constant (within our uncertainties). We use a physio-chemical parametric disk structure of the HD 97048 disk with an analytical prescription for the HCO+ abundance distribution to generate synthetic observations of the HCO+ and HĀ¹Ā³CO+ disk emission assuming LTE. The best by-eye fit models require radial variations in the HCO+/HĀ¹Ā³CO+ abundance ratio and an overall enhancement in HĀ¹Ā³CO+ relative to HCO+. This highlights the need to consider isotope selective chemistry and in particular low temperature carbon isotope exchange reactions. This also points to the presence of a reservoir of cold molecular gas in the outer disk (T ~ 10 K, R ~ 200 au). Chemical models are required to confirm that isotope-selective chemistry alone can explain the observations presented here. With these data, we cannot rule out that the known dust substructure in the HD 97048 disk is responsible for the observed trends in molecular line emission, and higher spatial resolution observations are required to fully explore the potential of optically thin tracers to probe planet-carved dust gaps. We also report non-detections of HĀ¹Ā³CO+ and HCĀ¹āµN in the HD 100546 protoplanetary disk

    Acute pancreatitis and hyperamylasemia in renal homograft recipients.

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    In a series of 301 renal homograft recipients, 17 (5.6%) had acute pancreatitis at some time after transplantation. Eleven of these patients died, for a mortality of 64.7%. In each instance, pancreatitis was a major factor in a complex chain of lethal events to which immunosuppression invariably contributed. An additional 43 patients (14.3%) developed asymptomatic hyperamylasemia after transplantation and, undoubtedly, some of these recipients also had pancreatitis. The factors causing pancreatitis in the renal transplantation patient include uremia, hyperparathyroidism, pancreatic injury by drugs, infections resulting from chronic immunosuppression, gallstones, and operative trauma to the pancreas. In cases of preexisting pancreatitis, transplantation is not necessarily precluded, but efforts should be made to find a specific cause of the pancreatitis and take corrective measures, such as biliary tract surgery or parathyroidectomy if indicated, in advance of transplantation

    An inherited complex organic molecule reservoir in a warm planet-hosting disk

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    Quantifying the composition of the material in protoplanetary disks is essential to determining the potential for exoplanetary systems to produce and support habitable environments. When considering potential habitability, complex organic molecules are relevant, key among which is methanol (CH3OH). Methanol primarily forms at low temperatures via the hydrogenation of CO ice on the surface of icy dust grains and is a necessary basis for the formation of more complex species such as amino acids and proteins. We report the detection of CH3OH in a disk around a young, luminous A-type star, HD 100546. This disk is warm and therefore does not host an abundant reservoir of CO ice. We argue that the CH3OH cannot form in situ, and hence that this disk has probably inherited complex-organic-molecule-rich ice from an earlier cold dark cloud phase. This is strong evidence that at least some interstellar organic material survives the disk-formation process and can then be incorporated into forming planets, moons and comets. Therefore, crucial pre-biotic chemical evolution already takes place in dark star-forming clouds

    Long-term lymphoid progenitors independently sustain naĆÆve T and NK cell production in humans.

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    Our mathematical model of integration site data in clinical gene therapy supported the existence of long-term lymphoid progenitors capable of surviving independently from hematopoietic stem cells. To date, no experimental setting has been available to validate this prediction. We here report evidence of a population of lymphoid progenitors capable of independently maintaining T and NK cellĀ production for 15 years in humans. The gene therapy patients of this study lack vector-positive myeloid/B cells indicating absence of engineered stem cells but retain gene marking in both T and NK. Decades after treatment, we can still detect and analyse transduced naĆÆve T cells whose production is likely maintained by a population of long-term lymphoid progenitors. By tracking insertional clonal markers overtime, we suggest that these progenitors can support both T and NK cell production. Identification of these long-term lymphoid progenitors could be utilised for the development of next generation gene- and cancer-immunotherapies

    Sulphur monoxide emission tracing an embedded planet in the HD 100546 protoplanetary disk

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    Molecular line observations are powerful tracers of the physical and chemical conditions across the different evolutionary stages of star, disk, and planet formation. The high angular resolution and unprecedented sensitivity of the Atacama Large Millimeter Array (ALMA) enables the current drive to detect small-scale gas structures in protoplanetary disks that can be attributed directly to forming planets. We report high angular resolution ALMA Band 7 observations of sulphur monoxide (SO) in the nearby planet-hosting disk around the Herbig star HD 100546. SO is rarely detected in evolved protoplanetary disks, but in other environments, it is most often used as a tracer of shocks. The SO emission from the HD 100546 disk primarily originates from gas within the ā‰ˆ20 au millimeter-dust cavity and shows a clear azimuthal brightness asymmetry of a factor of 2. In addition, the difference in the line profile shape is significant when these new Cycle 7 data are compared to Cycle 0 data of the same SO transitions. We discuss the different physical and chemical mechanisms that might cause this asymmetry and time variability, including disk winds, disk warps, and a shock triggered by a (forming) planet. We propose that SO is enhanced in the cavity by the presence of a giant planet. The SO asymmetry complements evidence for hot circumplanetary material around giant planet HD 100546 c that is traced via CO ro-vibrational emission. This work sets the stage for further observational and modelling efforts to detect and understand the chemical imprint of a forming planet on its parent disk

    In-cell NMR characterization of the secondary structure populations of a disordered conformation of Ī±-Synuclein within E. coli cells

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    Ī±-Synuclein is a small protein strongly implicated in the pathogenesis of Parkinsonā€™s disease and related neurodegenerative disorders. We report here the use of in-cell NMR spectroscopy to observe directly the structure and dynamics of this protein within E. coli cells. To improve the accuracy in the measurement of backbone chemical shifts within crowded in-cell NMR spectra, we have developed a deconvolution method to reduce inhomogeneous line broadening within cellular samples. The resulting chemical shift values were then used to evaluate the distribution of secondary structure populations which, in the absence of stable tertiary contacts, are a most effective way to describe the conformational fluctuations of disordered proteins. The results indicate that, at least within the bacterial cytosol, Ī±-synuclein populates a highly dynamic state that, despite the highly crowded environment, has the same characteristics as the disordered monomeric form observed in aqueous solution
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