216 research outputs found

    A new microvertebrate assemblage from the Mussentuchit Member, Cedar Mountain Formation: insights into the paleobiodiversity and paleobiogeography of early Late Cretaceous ecosystems in western North America

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    The vertebrate fauna of the Late Cretaceous Mussentuchit Member of the Cedar Mountain Formation has been studied for nearly three decades, yet the fossil-rich unit continues to produce new information about life in western North America approximately 97 million years ago. Here we report on the composition of the Cliffs of Insanity (COI) microvertebrate locality, a newly sampled site containing perhaps one of the densest concentrations of microvertebrate fossils yet discovered in the Mussentuchit Member. The COI locality preserves osteichthyan, lissamphibian, testudinatan, mesoeucrocodylian, dinosaurian, metatherian, and trace fossil remains and is among the most taxonomically rich microvertebrate localities in the Mussentuchit Member. To better refine taxonomic identifications of isolated theropod dinosaur teeth, we used quantitative analyses of taxonomically comprehensive databases of theropod tooth measurements, adding new data on theropod tooth morphodiversity in this poorly understood interval. We further provide the first descriptions of tyrannosauroid premaxillary teeth and document the earliest North American record of adocid remains, extending the appearance of this ancestrally Asian clade by 5 million years in western North America and supporting studies of pre-Cenomaninan Laurasian faunal exchange across Beringia. The overabundance of mesoeucrocodylian remains at the COI locality produces a comparatively low measure of relative biodiversity when compared to other microvertebrate sites in the Mussentuchit Member using both raw and subsampling methods. Much more microvertebrate research is necessary to understand the roles of changing ecology and taphonomy that may be linked to transgression of the Western Interior Seaway or microhabitat variation

    A Bitter Taste Receptor as a Novel Molecular Target on Cancer-Associated Fibroblasts in Pancreatic Ductal Adenocarcinoma

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    Cancer-associated fibroblasts (CAFs) execute diverse and complex functions in cancer progression. While reprogramming the crosstalk between CAFs and cancer epithelial cells is a promising avenue to evade the adverse effects of stromal depletion, drugs are limited by their suboptimal pharmacokinetics and off-target effects. Thus, there is a need to elucidate CAF-selective cell surface markers that can improve drug delivery and efficacy. Here, functional proteomic pulldown with mass spectrometry was used to identify taste receptor type 2 member 9 (TAS2R9) as a CAF target. TAS2R9 target characterization included binding assays, immunofluorescence, flow cytometry, and database mining. Liposomes conjugated to a TAS2R9-specific peptide were generated, characterized, and compared to naked liposomes in a murine pancreatic xenograft model. Proof-of-concept drug delivery experiments demonstrate that TAS2R9-targeted liposomes bind with high specificity to TAS2R9 recombinant protein and exhibit stromal colocalization in a pancreatic cancer xenograft model. Furthermore, the delivery of a CXCR2 inhibitor by TAS2R9-targeted liposomes significantly reduced cancer cell proliferation and constrained tumor growth through the inhibition of the CXCL-CXCR2 axis. Taken together, TAS2R9 is a novel cell-surface CAF-selective target that can be leveraged to facilitate small-molecule drug delivery to CAFs, paving the way for new stromal therapies

    An Infrared Coronagraphic Survey for Substellar Companions

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    We have used the F160W filter (1.4-1.8 um) and the coronagraph on the Near-InfraRed Camera and Multi-Object Spectrometer (NICMOS) on the Hubble Space Telescope (HST) to survey 45 single stars with a median age of 0.15 Gyr, an average distance of 30 pc, and an average H-magnitude of 7 mag. For the median age we were capable of detecting a 30 M_Jup companion at separations between 15 and 200 AU. A 5 M_Jup object could have been detected at 30 AU around 36% of our primaries. For several of our targets that were less than 30 Myr old, the lower mass limit was as low as a Jupiter mass, well into the high mass planet region. Results of the entire survey include the proper motion verification of five low-mass stellar companions, two brown dwarfs (HR7329B and TWA5B) and one possible brown dwarf binary (Gl 577B/C).Comment: 11 figures, accepted by A

    Aerospace Fuels From Nonpetroleum Raw Materials

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    Recycling human metabolic and plastic wastes minimizes cost and increases efficiency by reducing the need to transport consumables and return trash, respectively, from orbit to support a space station crew. If the much larger costs of transporting consumables to the Moon and beyond are taken into account, developing waste recycling technologies becomes imperative and possibly mission enabling. Reduction of terrestrial waste streams while producing energy and/or valuable raw materials is an opportunity being realized by a new generation of visionary entrepreneurs; several relevant technologies are briefly compared, contrasted and assessed for space applications. A two-step approach to nonpetroleum raw materials utilization is presented; the first step involves production of supply or producer gas. This is akin to synthesis gas containing carbon oxides, hydrogen, and simple hydrocarbons. The second step involves production of fuel via the Sabatier process, a methanation reaction, or another gas-to-liquid technology, typically Fischer-Tropsch processing. Optimization to enhance the fraction of product stream relevant to transportation fuels via catalytic (process) development at NASA Glenn Research Center is described. Energy utilization is a concern for production of fuels whether for operation on the lunar or Martian surface, or beyond. The term green relates to not only mitigating excess carbon release but also to the efficiency of energy usage. For space, energy usage can be an essential concern. Another issue of great concern is minimizing impurities in the product stream(s), especially those that are potential health risks and/or could degrade operations through catalyst poisoning or equipment damage; technologies being developed to remove heteroatom impurities are discussed. Alternative technologies to utilize waste fluids, such as a propulsion option called the resistojet, are discussed. The resistojet is an electric propulsion technology with a powered thruster to vaporize and heat a propellant to high temperature, hot gases are subsequently passed through a converging-diverging nozzle expanding gases to supersonic velocities. A resistojet can accommodate many different fluids, including various reaction chamber (by-)products

    The higher-level phylogeny of Archosauria (Tetrapoda:Diapsida)

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    Crown group Archosauria, which includes birds, dinosaurs, crocodylomorphs, and several extinct Mesozoic groups, is a primary division of the vertebrate tree of life. However, the higher-level phylogenetic relationships within Archosauria are poorly resolved and controversial, despite years of study. The phylogeny of crocodile-line archosaurs (Crurotarsi) is particularly contentious, and has been plagued by problematic taxon and character sampling. Recent discoveries and renewed focus on archosaur anatomy enable the compilation of a new dataset, which assimilates and standardizes character data pertinent to higher-level archosaur phylogeny, and is scored across the largest group of taxa yet analysed. This dataset includes 47 new characters (25% of total) and eight taxa that have yet to be included in an analysis, and total taxonomic sampling is more than twice that of any previous study. This analysis produces a well-resolved phylogeny, which recovers mostly traditional relationships within Avemetatarsalia, places Phytosauria as a basal crurotarsan clade, finds a close relationship between Aetosauria and Crocodylomorpha, and recovers a monophyletic Rauisuchia comprised of two major subclades. Support values are low, suggesting rampant homoplasy and missing data within Archosauria, but the phylogeny is highly congruent with stratigraphy. Comparison with alternative analyses identifies numerous scoring differences, but indicates that character sampling is the main source of incongruence. The phylogeny implies major missing lineages in the Early Triassic and may support a Carnian-Norian extinction event.Marshall Scholarship for study in the United KingdomJurassic FoundationUniversity of BristolPaleontological Societ

    Cerium Oxide Nanoparticles Protect Cardiac Progenitor Cells from Oxidative Stress

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    Cardiac progenitor cells (CPCs) are a promising autologous source of cells for cardiac regenerative medicine. However, CPC culture in vitro requires the presence of microenvironmental conditions (a complex array of bioactive substance concentration, mechanostructural factors, and physicochemical factors) closely mimicking the natural cell surrounding in vivo, including the capability to uphold reactive oxygen species (ROS) within physiological levels in vitro. Cerium oxide nanoparticles (nanoceria) are redox-active and could represent a potent tool to control the oxidative stress in isolated CPCs. Here, we report that 24 h exposure to 5, 10, and 50 !g/mL of nanoceria did not a!ect cell growth and function in cardiac progenitor cells, while being able to protect CPCs from H2O2-induced cytotoxicity for at least 7 days, indicating that nanoceria in an e!ective antioxidant. Therefore, these "ndings con"rm the great potential of nanoceria for controlling ROS-induced cell damage

    The 4D nucleome project

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