138 research outputs found

    Air Retention under Water by the Floating Fern Salvinia: The Crucial Role of a Trapped Air Layer as a Pneumatic Spring

    Get PDF
    The ability of floating ferns Salvinia to keep a permanent layer of air under water is of great interest, e.g., for drag‐reducing ship coatings. The air‐retaining hairs are superhydrophobic, but have hydrophilic tips at their ends, pinning the air–water interface. Here, experimental and theoretical approaches are used to examine the contribution of this pinning effect for air‐layer stability under pressure changes. By applying the capillary adhesion technique, the adhesion forces of individual hairs to the water surface is determined to be about 20 µN per hair. Using confocal microscopy and fluorescence labeling, it is found that the leaves maintain a stable air layer up to an underpressure of 65 mbar. Combining both results, overall pinning forces are obtained, which account for only about 1% of the total air‐retaining force. It is suggested that the restoring force of the entrapped air layer is responsible for the remaining 99%. This model of the entrapped air acting is verified as a pneumatic spring (“air‐spring”) by an experiment shortcircuiting the air layer, which results in immediate air loss. Thus, the plant enhances its air‐layer stability against pressure fluctuations by a factor of 100 by utilizing the entrapped air volume as an elastic spring

    Vehicle Integrated Prognostic Reasoner (VIPR) 2010 Annual Final Report

    Get PDF
    Honeywell's Central Maintenance Computer Function (CMCF) and Aircraft Condition Monitoring Function (ACMF) represent the state-of-the art in integrated vehicle health management (IVHM). Underlying these technologies is a fault propagation modeling system that provides nose-to-tail coverage and root cause diagnostics. The Vehicle Integrated Prognostic Reasoner (VIPR) extends this technology to interpret evidence generated by advanced diagnostic and prognostic monitors provided by component suppliers to detect, isolate, and predict adverse events that affect flight safety. This report describes year one work that included defining the architecture and communication protocols and establishing the user requirements for such a system. Based on these and a set of ConOps scenarios, we designed and implemented a demonstration of communication pathways and associated three-tiered health management architecture. A series of scripted scenarios showed how VIPR would detect adverse events before they escalate as safety incidents through a combination of advanced reasoning and additional aircraft data collected from an aircraft condition monitoring system. Demonstrating VIPR capability for cases recorded in the ASIAS database and cross linking them with historical aircraft data is planned for year two

    Percutaneous coronary intervention of chronic total occlusions involving a bifurcation: Insights from the PROGRESS-CTO registry

    Get PDF
    BACKGROUND: The impact of bifurcations at the proximal or distal cap on the outcomes of chronic total occlusion (CTO) percutaneous coronary intervention (PCI) has received limited study. METHODS: We analyzed the clinical, angiographic, and procedural data of 4,584 cases performed in patients between 2012 and 2020 in a global CTO PCI registry. We compared 4 groups according to the bifurcation location: proximal cap, distal cap, proximal and distal cap, and no bifurcation. RESULTS: The CTO involved a bifurcation in 67% cases, as follows: proximal cap (n = 1451, 33%), distal cap (n = 622, 14%), or both caps (n = 954, 21%). Proximal and distal cap cases had higher J-CTO compared with proximal cap, distal cap, and no bifurcation cases (2.9 ± 1.1 vs 2.5 ± 1.1 vs 2.4 ± 1.2 vs 2.0 ± 1.2, P \u3c 0.0001), and they were also associated with a lower technical success rate (79% vs 85% vs 85% vs 90%, P \u3c 0.0001), higher pericardiocentesis rate (1% vs 1% vs 0.2% vs 0.3%, P = 0.02), and higher emergency coronary artery bypass graft surgery rate (0.3% vs 0% vs 0% vs 0%, P = 0.01). CONCLUSION: More than two-thirds of CTO PCIs involve a bifurcation, which is associated with lower technical success and higher risk of complications

    Investigation of pre-structured GaAs surfaces for subsequent site-selective InAs quantum dot growth

    Get PDF
    In this study, we investigated pre-structured (100) GaAs sample surfaces with respect to subsequent site-selective quantum dot growth. Defects occurring in the GaAs buffer layer grown after pre-structuring are attributed to insufficient cleaning of the samples prior to regrowth. Successive cleaning steps were analyzed and optimized. A UV-ozone cleaning is performed at the end of sample preparation in order to get rid of remaining organic contamination

    A single tRNA base pair mediates bacterial tRNA-dependent biosynthesis of asparagine

    Get PDF
    In many prokaryotes and in organelles asparagine and glutamine are formed by a tRNA-dependent amidotransferase (AdT) that catalyzes amidation of aspartate and glutamate, respectively, mischarged on tRNA(Asn) and tRNA(Gln). These pathways supply the deficiency of the organism in asparaginyl- and glutaminyl-tRNA synthtetases and provide the translational machinery with Asn-tRNA(Asn) and Gln-tRNA(Gln). So far, nothing is known about the structural elements that confer to tRNA the role of a specific cofactor in the formation of the cognate amino acid. We show herein, using aspartylated tRNA(Asn) and tRNA(Asp) variants, that amidation of Asp acylating tRNA(Asn) is promoted by the base pair U(1)–A(72) whereas the G(1)–C(72) pair and presence of the supernumerary nucleotide U(20A) in the D-loop of tRNA(Asp) prevent amidation. We predict, based on comparison of tRNA(Gln) and tRNA(Glu) sequence alignments from bacteria using the AdT-dependent pathway to form Gln-tRNA(Gln), that the same combination of nucleotides also rules specific tRNA-dependent formation of Gln. In contrast, we show that the tRNA-dependent conversion of Asp into Asn by archaeal AdT is mainly mediated by nucleotides G(46) and U(47) of the variable region. In the light of these results we propose that bacterial and archaeal AdTs use kingdom-specific signals to catalyze the tRNA-dependent formations of Asn and Gln

    Towards a Digital Twin of the Earth System: Geo-Soft-CoRe, a Geoscientific Software & Code Repository

    Get PDF
    [Abstract] The immense advances in computer power achieved in the last decades have had a significant impact in Earth science, providing valuable research outputs that allow the simulation of complex natural processes and systems, and generating improved forecasts. The development and implementation of innovative geoscientific software is currently evolving towards a sustainable and efficient development by integrating models of different aspects of the Earth system. This will set the foundation for a future digital twin of the Earth. The codification and update of this software require great effort from research groups and therefore, it needs to be preserved for its reuse by future generations of geoscientists. Here, we report on Geo-Soft-CoRe, a Geoscientific Software & Code Repository, hosted at the archive DIGITAL.CSIC. This is an open source, multidisciplinary and multiscale collection of software and code developed to analyze different aspects of the Earth system, encompassing tools to: 1) analyze climate variability; 2) assess hazards, and 3) characterize the structure and dynamics of the solid Earth. Due to the broad range of applications of these software packages, this collection is useful not only for basic research in Earth science, but also for applied research and educational purposes, reducing the gap between the geosciences and the society. By providing each software and code with a permanent identifier (DOI), we ensure its self-sustainability and accomplish the FAIR (Findable, Accessible, Interoperable and Reusable) principles. Therefore, we aim for a more transparent science, transferring knowledge in an easier way to the geoscience community, and encouraging an integrated use of computational infrastructure.This research has been funded by the Projects EPOS IP 676564, EPOS SP 871121, SERA 730900, GeoCAM (PGC2018-095154-B-I00, Spanish Government) and the Center of Excellence for Exascale in Solid Earth (ChEESE) under the Grant Agreement 823844. IDF was funded by a FEDER-Junta de Castilla y León Postdoctoral contract (SA0084P20). JA and M-GL are funded by the Spanish Ministry of Science and Innovation through the Juan de la Cierva fellowship (IJC 2018-036074-I and IJC 2018-036826-I, respectively), funded by MCIN/AEI /10.13039/501100011033. AH is grateful for his Ramón y Cajal contract (RYC 2020-029253-I). Additional funding was provided by the Spanish Ministry of Science and Innovation (RTI 2018-095594-B-I00, PGC 2018-095154-B-100) and the Generalitat de Catalunya (AGAUR, 2017SGR1022). AP’s work was supported by: a Science Foundation Ireland Career Development Award (17/CDA/4695); an investigator award (16/IA/4520); a Marine Research Programme funded by the Irish Government, co-financed by the European Regional Development Fund (Grant-Aid Agreement No. PBA/CC/18/01); European Union’s Horizon 2020 research and innovation programme InnoVar under grant agreement No 818144; SFI Centre for Research Training in Foundations of Data Science 18/CRT/6049, and SFI Research Centre awards I-Form 16/RC/3872 and Insight 12/RC/2289_P2. AH and SG thank the Spanish research project PaleoModes (CGL2016-75281-C2-1-R) which provided some of their financial support. JF is supported by an Atracción de Talento senior fellowship (2018-T1/AMB/11493) funded by Comunidad Autonoma de Madrid (Spain), and a project funded by the Spanish Ministry of Science and Innovation (PID2020-114854GB-C22)Junta de Castilla y León; SA0084P20Generalitat de Catalunya; 2017SGR1022Science Foundation Ireland; 17/CDA/4695Science Foundation Ireland; 16/IA/4520Ireland. Marine Institute; PBA/CC/18/01Science Foundation Ireland; 18/CRT/6049Science Foundation Ireland; 16/RC/3872Science Foundation Ireland; 12/RC/2289_P2Comunidad Autonoma de Madrid; 2018-T1/AMB/1149

    Prognostic relevance of MOG antibodies in children with an acquired demyelinating syndrome

    Get PDF
    Objective: To assess the prognostic value of MOG antibodies (abs) in the differential diagnosis of acquired demyelinating syndromes (ADS). Methods: Clinical course, MRI, MOG-abs, AQP4-abs, and CSF cells and oligoclonal bands (OCB) in children with ADS and 24 months of follow-up were reviewed in this observational prospective multicenter hospital-based study. Results: Two hundred ten children with ADS were included and diagnosed with acute disseminated encephalomyelitis (ADEM) (n = 60), neuromyelitis optica spectrum disorder (NMOSD) (n = 12), clinically isolated syndrome (CIS) (n = 101), and multiple sclerosis (MS) (n = 37) after the first episode. MOG-abs were predominantly found in ADEM (57%) and less frequently in NMOSD (25%), CIS (25%), or MS (8%). Increased MOG-ab titers were associated with younger age (p = 0.0001), diagnosis of ADEM (p = 0.005), increased CSF cell counts (p = 0.011), and negative OCB (p = 0.012). At 24-month follow-up, 96 children had no further relapses. Thirtyfive children developed recurrent non-MS episodes (63% MOG-, 17% AQP4-abs at onset). Seventy-nine children developed MS (4% MOG-abs at onset). Recurrent non-MS episodes were associated with high MOG-ab titers (p = 0.0003) and older age at onset (p = 0.024). MS was predicted by MS-like MRI (p = 1:1,280 predicted a non-MS course with a sensitivity of 47% and a specificity of 100% and a recurrent non-MS course with a sensitivity of 46% and a specificity of 86%. Conclusions: Our results show that the presence of MOG-abs strongly depends on the age at disease onset and that high MOG-ab titers were associated with a recurrent non-MS disease course
    corecore