15,745 research outputs found

    Spectroscopic evidence of charge exchange X-ray emission from galaxies

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    What are the origins of the soft X-ray line emission from non-AGN galaxies? XMM-Newton RGS spectra of nearby non-AGN galaxies (including starforming ones: M82, NGC 253, M51, M83, M61, NGC 4631, M94, NGC 2903, and the Antennae galaxies, as well as the inner bulge of M31) have been analyzed. In particular, the K{\alpha} triplet of O VII shows that the resonance line is typically weaker than the forbidden and/or inter-combination lines. This suggests that a substantial fraction of the emission may not arise directly from optically thin thermal plasma, as commonly assumed, and may instead originate at its interface with neutral gas via charge exchange. This latter origin naturally explains the observed spatial correlation of the emission with various tracers of cool gas in some of the galaxies. However, alternative scenarios, such as the resonance scattering by the plasma and the relic photo-ionization by AGNs in the recent past, cannot be ruled out, at least in some cases, and are being examined. Such X-ray spectroscopic studies are important to the understanding of the relationship of the emission to various high-energy feedback processes in galaxies.Comment: 5 pages, published in Astronomical Notes, for "Charge exchange in the Universe" workshop, Paris 201

    The Impact of IT spending and Vendor Interaction on Innovation Deployment in Hospitals

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    This paper examines the impact of financial investment and vendor interactions on the availability of electronic health record (EHR) systems to healthcare workers and patients, which in turn impacts technology usage and hospital performance. We used hospital‐level data from the American Hospital Association (AHA) IT Supplemental Survey, the AHA Annual Survey Database, and the Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) survey to test the EHR systems deployment model. The results show that both financial investment and vendor interactions significantly influence the availability of the HER in hospitals. Especially, collaboration with dominant vendors can lead to the high availability of the system and better performance

    microRNA-33a-5p increases radiosensitivity by inhibiting glycolysis in melanoma.

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    Glycolysis was reported to have a positive correlation with radioresistance. Our previous study found that the miR-33a functioned as a tumor suppressor in malignant melanoma by targeting hypoxia-inducible factor1-alpha (HIF-1α), a gene known to promote glycolysis. However, the role of miR-33a-5p in radiosensitivity remains to be elucidated. We found that miR-33a-5p was downregulated in melanoma tissues and cells. Cell proliferation was downregulated after overexpression of miR-33a-5p in WM451 cells, accompanied by a decreased level of glycolysis. In contrast, cell proliferation was upregulated after inhibition of miR-33a-5p in WM35 cells, accompanied by increased glycolysis. Overexpression of miR-33a-5p enhanced the sensitivity of melanoma cells to X-radiation by MTT assay, while downregulation of miR-33a-5p had the opposite effects. Finally, in vivo experiments with xenografts in nude mice confirmed that high expression of miR-33a-5p in tumor cells increased radiosensitivity via inhibiting glycolysis. In conclusions, miR-33a-5p promotes radiosensitivity by negatively regulating glycolysis in melanoma
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