62 research outputs found

    The HI Chronicles of LITTLE THINGS BCDs: Evidence for External Perturbations in the Morphology and Kinematics of Haro 29 and Haro 36

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    We analyze high angular and velocity resolution HI-line data of two LITTLE THINGS (1) blue compact dwarfs (BCDs): Haro 29 and Haro 36. Both of these BCDs are disturbed morphologically and kinematically. Haro 29's HI data reveal a kinematic major axis that is offset from the optical major axis, and a disturbed outer HI component, indicating that Haro 29 may have had a past interaction. Position-velocity diagrams of Haro 36 indicate that it has two kinematically separate components at its center and a likely tidal tail in front of the galaxy. We find that Haro 36 most likely had an interaction in the past, is currently interacting with an unknown companion, or is a merger remnant. (1) "Local Irregulars That Trace Luminosity Extremes The HI Nearby Galaxy Survey" http://www2.lowell.edu/users/dah/littlethings/index.htmlComment: To be published in The Astronomical Journa

    The HI Chronicles of LITTLE THINGS BCDs II: The Origin of IC 10's HI Structure

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    In this paper we analyze Very Large Array (VLA) telescope and Green Bank Telescope (GBT) atomic hydrogen (HI) data for the LITTLE THINGS(1) blue compact dwarf galaxy IC 10. The VLA data allow us to study the detailed HI kinematics and morphology of IC 10 at high resolution while the GBT data allow us to search the surrounding area at high sensitivity for tenuous HI. IC 10's HI appears highly disturbed in both the VLA and GBT HI maps with a kinematically distinct northern HI extension, a kinematically distinct southern plume, and several spurs in the VLA data that do not follow the general kinematics of the main disk. We discuss three possible origins of its HI structure and kinematics in detail: a current interaction with a nearby companion, an advanced merger, and accretion of intergalactic medium. We find that IC 10 is most likely an advanced merger or a galaxy undergoing accretion. 1:Local Irregulars That Trace Luminosity Extremes, The HI Nearby Galaxy Survey; https://science.nrao.edu/science/surveys/littlethingsComment: 36 pages, 17 figures, accepted for publication in The Astronomical Journa

    VII ZW 403, STRUCTURE RESOLVED IN A BLUE COMPACT DWARF GALAXY

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    ABSTRACT VII Zw 403 is a blue compact dwarf galaxy, with one unresolved x-ray source. The galaxy was previously observed with the Very Large Array Radio Telescope in Socorro, New Mexico while in the C and D configurations; the data being analyzed in this paper are from the B-configuration. With these data, we have found some previously unresolved structure in the atomic hydrogen (H I) around an X-ray point source and other regions of the galaxy because of the higher resolution offered by the B-configuration. We are also able to see two differently oriented axes of rotation in the galaxy when the B, C, and D data are combined. One question that still needs to be explored is whether or not the x-ray source is the cause of some or all of the hole-like structure in the northeast section of the H I of the galaxy. This work may also shed light on how blue compact dwarf galaxies undergo starbursts without an obvious instigator

    VII Zw 403: H I structure in a blue compact dwarf galaxy

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    ‘In these times, during the rise in the popularity of institutional repositories, the Society does not forbid authors from depositing their work in such repositories. However, the AAS regards the deposit of scholarly work in such repositories to be a decision of the individual scholar, as long as the individual's actions respect the diligence of the journals and their reviewers.’ Original article can be found at : http://iopscience.iop.org/ Copyright American Astronomical SocietyWe present optical (UBVJ), ultraviolet (FUV, NUV), and high-resolution atomic hydrogen (H I) observations of the nearby blue compact dwarf (BCD), VII Zw 403. We find that VII Zw 403 has a relatively high H I mass-to-light ratio for a BCD. The rotation velocity is nominally 10-15 km s(-1), but rises to similar to 20 km s(-1) after correction for the similar to 8-10 km s(-1) random motions present in the gas. The velocity field is complex, including a variation in the position angle of the major axis going from the northeast to the southwest parts of the galaxy. Our high-resolution Hi maps reveal structure in the central gas, including a large, low-density Hi depression or hole between the southern and northern halves of the galaxy, coincident with an unresolved X-ray source. Although interactions have been proposed as the triggering mechanism for the vigorous star formation occurring in BCDs, VII Zw 403 does not seem to have been tidally triggered by an external interaction, as we have found no nearby possible perturbers. It also does not appear to fall in the set of galaxies that exhibit a strong central mass density concentration, as its optical scale length is large in comparison to similar systems. However, there are some features that are compatible with an accretion event: optical/Hi axis misalignment, a change in position angle of the kinematic axis, and a complex velocity field.Peer reviewe

    A Narrative Review of the Applications of Ex-vivo Human Liver Perfusion

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    Ex-vivo perfusion describes the extra-corporeal delivery of fluid to an organ or tissue. Although it has been widely studied in the context of organ preservation and transplantation, it has also proven to be an invaluable tool in the development of novel models for translational pre-clinical research. Here, we review the literature reporting ex-vivo human liver perfusion experiments to further understand current perfusion techniques and protocols together with their applications. A computerised search was made of Ovid, MEDLINE, and Embase using the search words “ex-vivo liver or hepatic perfusion”. All relevant studies in English describing experiments using ex-vivo perfusion of human livers between 2016 and 2021, inclusive, were included. Of 21 reviewed studies, 19 used ex-vivo human liver perfusion in the context of allogeneic liver transplantation. The quality and size of the studies varied considerably. Human liver perfusion was almost exclusively limited to whole organs and “split” livers, although one study did describe the successful perfusion of tissue sections following a partial hepatectomy. This review of recent literature involving ex vivo human liver perfusion demonstrates that the technique is not limited to whole liver perfusion. Split liver perfusion is extremely valuable allowing one lobe to act as a control and increasing the number available for research. This review also highlights the present lack of any reports of segmental liver perfusion. The discarded donor liver is a scarce resource, and the successful use of segmental perfusion has the potential to expand the available experimental models to facilitate pre-clinical experimentation

    Diverse metallicities of Fermi bubble clouds indicate dual origins in the disk and halo

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    The Galactic Center is surrounded by two giant plasma lobes known as the Fermi Bubbles, extending ~10 kpc both above and below the Galactic plane. Spectroscopic observations of Fermi Bubble directions at radio, ultraviolet, and optical wavelengths have detected multi-phase gas clouds thought to be embedded within the bubbles referred to as Fermi Bubble high-velocity clouds (FB HVCs). While these clouds have kinematics that can be modeled by a biconical nuclear wind launched from the Galactic center, their exact origin is unknown because, until now, there has been little information on their heavy-metal abundance (metallicity). Here we show that FB HVCs have a wide range of metallicities from <20% solar to ~320% solar. This result is based on the first metallicity survey of FB HVCs. These metallicities challenge the previously accepted tenet that all FB HVCs are launched from the Galactic center into the Fermi Bubbles with solar or super-solar metallicities. Instead, we suggest that FB HVCs originate in both the Milky Way's disk and halo. As such, some of these clouds may characterize circumgalactic medium that the Fermi Bubbles expand into, rather than material carried outward by the nuclear wind, changing the canonical picture of FB HVCs. More broadly, these results reveal that nuclear outflows from spiral galaxies can operate by sweeping up gas in their halos while simultaneously removing gas from their disks.Comment: This version of the article has been accepted for publication on Nature Astronomy after peer review. This version is not the Version of Record (https://doi.org/10.1038/s41550-022-01720-0) and does not reflect post-acceptance improvements, or any correction

    Nano-ablative immunotherapy for cancer treatment

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    Immunotherapy has provided a new avenue to treat metastatic cancers, which result in ∼90% of cancer related deaths. However, current immunotherapies, such as immune checkpoint therapy (ICT), have met with limited success, primarily due to tumor intrinsic and extrinsic factors that inhibit antitumor immune responses. To overcome the immune suppression of the tumor microenvironment (TME) and enhance the tumoricidal activity of ICT, phototherapy, particularly photothermal therapy (PTT), combined with nanomedicine has become a viable option. PTT disrupts target tumor homeostasis, releasing tumor associated antigens (TAAs), tumor specific antigens (TSAs), danger associated molecular patterns (DAMPs), and scarce nutrients required to “feed” activated antitumor immune cells. While nanoparticles localize and specify the phototherapeutic effect, they can also be loaded with immune stimulants, TME modulators, and/or chemotherapeutic agents to greatly enhance immune stimulation and tumor killing. Combining these three technologies, which we term nano-ablative immunotherapy (NAIT), with ICT can greatly enhance their therapeutic effects. In this review, we will discuss the successes and limitations of NAIT + ICT. Specifically, we will discuss how the TME limits tumoricidal activity and what should be considered to overcome these limitations.This work was supported in part by grants R01CA205348 from the National Cancer Institution (doi.org/10.13039/100008569) and HR16-085 and HF20-019 from the Oklahoma Center for the Advancement of Science and Technology (doi.org/10.13039/100008569). Open Access fees paid for in whole or in part by the University of Oklahoma Libraries.Ye
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