9,354 research outputs found

    Catalytic reaction between adsorbed oxygen and hydrogen on Rh(111)

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    Evaluation of Mobility Modes on Lunar Exploration Traverses - Marius Hills, Copernicus Peaks, and Hadley Apennines Missions

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    Energy and time costs of lunar walking or riding traverses, and scientific tasks on J-type missions, and capabilities of A7L suits and life support system

    Calculation of AGARD Wing 445.6 Flutter Using Navier-Stokes Aerodynamics

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    An unsteady, 3D, implicit upwind Euler/Navier-Stokes algorithm is here used to compute the flutter characteristics of Wing 445.6, the AGARD standard aeroelastic configuration for dynamic response, with a view to the discrepancy between Euler characteristics and experimental data. Attention is given to effects of fluid viscosity, structural damping, and number of structural model nodes. The flutter characteristics of the wing are determined using these unsteady generalized aerodynamic forces in a traditional V-g analysis. The V-g analysis indicates that fluid viscosity has a significant effect on the supersonic flutter boundary for this wing

    Multiscalar cellular automaton simulates in-vivo tumour-stroma patterns calibrated from in-vitro assay data

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    Background: The tumour stroma -or tumour microenvironment- is an important constituent of solid cancers and it is thought to be one of the main obstacles to quantitative translation of drug activity between the preclinical and clinical phases of drug development. The tumour-stroma relationship has been described as being both pro- and antitumour in multiple studies. However, the causality of this complex biological relationship between the tumour and stroma has not yet been explored in a quantitative manner in complex tumour morphologies.Methods: To understand how these stromal and microenvironmental factors contribute to tumour physiology and how oxygen distributes within them, we have developed a lattice-based multiscalar cellular automaton model. This model uses principles of cytokine and oxygen diffusion as well as cell motility and plasticity to describe tumour-stroma landscapes. Furthermore, to calibrate the model, we propose an innovative modelling platform to extract model parameters from multiple in-vitro assays. This platform provides a novel way to extract meta-data that can be used to complement in-vivo studies and can be further applied in other contexts.Results: Here we show the necessity of the tumour-stroma opposing relationship for the model simulations to successfully describe the in-vivo stromal patterns of the human lung cancer cell lines Calu3 and Calu6, as models of clinical and preclinical tumour-stromal topologies. This is especially relevant to drugs that target the tumour microenvironment, such as antiangiogenics, compounds targeting the hedgehog pathway or immune checkpoint inhibitors, and is potentially a key platform to understand the mechanistic drivers for these drugs.Conclusion: The tumour-stroma automaton model presented here enables the interpretation of complex in-vitro data and uses it to parametrise a model for in-vivo tumour-stromal relationships

    Identification of mixed-symmetry states in an odd-mass nearly-spherical nucleus

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    The low-spin structure of 93Nb has been studied using the (n,n' gamma) reaction at neutron energies ranging from 1.5 to 3.0 MeV and the 94Zr(p,2n gamma)93Nb reaction at bombarding energies from 11.5 to 19 MeV. States at 1779.7 and 1840.6 keV, respectively, are proposed as mixed-symmetry states associated with the coupling of a proton hole in the p_1/2 orbit to the 2+_1,ms state in 94Mo. These assignments are derived from the observed M1 and E2 transition strengths to the symmetric one-phonon states, energy systematics, spins and parities, and comparison with shell model calculations.Comment: 5 pages, 3 figure

    Development and Performance of the Nanoworkbench: A Four Tip STM for Electrical Conductivity Measurements Down to Sub-micrometer Scales

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    A multiple-tip ultra-high vacuum (UHV) scanning tunneling microscope (MT-STM) with a scanning electron microscope (SEM) for imaging and molecular-beam epitaxy growth capabilities has been developed. This instrument (nanoworkbench) is used to perform four-point probe conductivity measurements at micrometer spatial dimension. The system is composed of four chambers, the multiple-tip STM/SEM chamber, a surface analysis and preparation chamber, a molecular-beam epitaxy chamber and a load-lock chamber for fast transfer of samples and probes. The four chambers are interconnected by a unique transfer system based on a sample box with integrated heating and temperature-measuring capabilities. We demonstrate the operation and the performance of the nanoworkbench with STM imaging on graphite and with four-point-probe conductivity measurements on a silicon-on-insulator (SOI) crystal. The creation of a local FET, whose dimension and localization are respectively determined by the spacing between the probes and their position on the SOI surface, is demonstrated.Comment: 39 pages, 15 figure

    Changes in myoblast responsiveness to TNFα and IL-6 contribute to decreased skeletal muscle mass in intrauterine growth restricted fetal sheep

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    Intrauterine growth restriction (IUGR) is a leading cause of perinatal morbidity and mortality (Alisi et al., 2011). Skeletal muscle growth is disproportionately reduced in IUGR fetuses and offspring (Padoan et al. 2004; Yates et al. 2014). These individuals present with reduced muscle mass and increased risk for metabolic disorders at all stages of life (Godfrey and Barker, 2000; Yates et al. 2016.). Muscle growth requires proliferation, differentiation, and fusion of myoblasts (muscle stem cells) to form muscle fibers early in gestation and to increase myonuclear content of existing fibers during late gestation and after birth (Yates et al., 2014). These processes can be disrupted by inflammation, which is a potential factor in impaired muscle development in the IUGR fetus (Yates et al., 2012; Cadaret et al., 2017). Tumor necrosis factor-alpha (TNFα) and interleukin 6 (IL-6) are potent multifunctional cytokines involved in inflammatory and noninflammatory skeletal muscle disorders (Tüzün et al., 2006). We recently found that changes in gene expression of these cytokines and muscle sensitivity to them differed between IUGR and control rats (Cadaret et al., 2017), and that maternal inflammation induced fetal leukocyte adaptations, increasing gene expression of TNFα and its receptor TNFR1, but decreasing gene expression of IL-6 receptor. Both cytokines also regulate myoblast proliferation and differentiation outside of inflammatory states (Al-Shanti et al., 2008). These findings indicate TNFα and IL-6 are essential factors in proper growth and development of muscle, and thus, we postulate that expression and sensitivity changes contribute to decreased muscle growth capacity in IUGR fetuses. The objective of this study was to determine the effects of cytokines on fetal myoblast function and to determine if altered responsiveness is intrinsic in IUGR myoblasts, which would represent a potential adaptive mechanism for reduced muscle mass in IUGR offspring

    Inelastic Neutron Scattering Cross Section Measurements for \u3csup\u3e134,136\u3c/sup\u3eXe of Relevance to Neutrinoless Double-\u3cem\u3eβ\u3c/em\u3e Decay Searches

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    Neutrinoless double-β decay (0νββ) searches typically involve large-scale experiments for which backgrounds can be complex. One possible source of background near the 0νββ signature in the observed spectra is γ rays arising from inelastic neutron scattering from the materials composing or surrounding the detector. In relation to searches for the 0νββ of 136Xe to 136Ba, such as the EXO-200 and KamLAND-Zen projects, inelastic neutron scattering γ-ray production cross sections for 136Xe and 134Xe are of importance for characterizing such γ rays that may inhibit the unambiguous identification of this yet-to-be-observed process. These cross sections have been measured at the University of Kentucky Accelerator Laboratory at neutron energies from 2.5 to 4.5 MeV

    Ligament Tissue Engineering and Its Potential Role in Anterior Cruciate Ligament Reconstruction

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    Tissue engineering is an emerging discipline that combines the principle of science and engineering. It offers an unlimited source of natural tissue substitutes and by using appropriate cells, biomimetic scaffolds, and advanced bioreactors, it is possible that tissue engineering could be implemented in the repair and regeneration of tissue such as bone, cartilage, tendon, and ligament. Whilst repair and regeneration of ligament tissue has been demonstrated in animal studies, further research is needed to improve the biomechanical properties of the engineered ligament if it is to play an important part in the future of human ligament reconstruction surgery. We evaluate the current literature on ligament tissue engineering and its role in anterior cruciate ligament reconstruction
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