502 research outputs found

    Anti-inflammatory activity of Wnt signaling in enteric nervous system: in vitro preliminary evidences in rat primary cultures

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    Background: In the last years, Wnt signaling was demonstrated to regulate inflammatory processes. In particular, an increased expression of Wnts and Frizzled receptors was reported in inflammatory bowel disease (IBD) and ulcerative colitis to exert both anti- and pro-inflammatory functions regulating the intestinal activated nuclear factor \u3baB (NF-\u3baB), TNFa release, and IL10 expression. Methods: To investigate the role of Wnt pathway in the response of the enteric nervous system (ENS) to inflammation, neurons and glial cells from rat myenteric plexus were treated with exogenous Wnt3a and/or LPS with or without supporting neurotrophic factors such as basic fibroblast growth factor (bFGF), epithelial growth factor (EGF), and glial cell-derived neurotrophic factor (GDNF). The immunophenotypical characterization by flow cytometry and the protein and gene expression analysis by qPCR and Western blotting were carried out. Results: Flow cytometry and immunofluorescence staining evidenced that enteric neurons coexpressed Frizzled 9 and toll-like receptor 4 (TLR4) while glial cells were immunoreactive to TLR4 and Wnt3a suggesting that canonical Wnt signaling is active in ENS. Conclusions: The results of this study suggested the existence of neuronal surveillance through FZD9 and Wnt3a in enteric myenteric plexus. Moreover, experimental evidences were provided to clarify the correlation among soluble trophic factors, Wnt signaling, and anti-inflammatory protection of ENS

    Vibration Damping Measurement on Car Windshields

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    Knowledge of the damping properties of a windshield is a fundamental element of the acoustical characterization of a car. The measuring method of damping for a windshield is presented in the paper. The damping loss factor – as a basic measure of mechanical damping – was determined experimentally by two means: the reverberation time from impact hammer testing as well as the modal behavior from 3D laser scanning vibrometer measurements. The results proved that the modal shapes have a fundamental effect on the measured damping values

    Разработка и исследование возможностей кровати-трансформера для людей с ограниченными функциями

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    Магистерская диссертация посвящена разработке и исследованию медицинской кровати-трансформер. В процессе исследования физических возможностей человека, использующего и обслуживающего реабилитационную кровать, была спроектирована установка "Кровать-трансформер". В процессе создания установки было спроектировано несколько вариаций конструкции кровати с разным функционалом, а также в работе проведено исследование на сравнение приводов для трансформации кровати. В работе освещены такие темы как "Появление и трансформация с течением времени многофункциональных медицинских кроватей" и "Особенности больных с ограниченными возможностями". Проведены финансовые расчеты и исследования безопасности при производстве и эксплуатации конструкции.The master's thesis is devoted to the development and research of a medical transformer bed. In the process of studying the physical capabilities of a person using and servicing a rehabilitation bed, the “Transformer bed” installation was designed. In the process of creating the installation, several variations in the design of the bed with different functionalities were designed, and a study was conducted to compare the drives for transforming the bed. The work covers topics such as “The emergence and transformation over time of multifunctional medical beds” and “Features of patients with disabilities.” Conducted financial calculations and safety studies in the production and operation of the structure

    Investigation of the evaporation process of liquefied hydrocarbons in front of a compressor

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    International audienceInlet fogging and wet compression are well known methods to lower the inlet temperature of air compressors of gas turbines and in this way lead to a more efficient compression process. Injection of water into the gas stream is another established method to reduce the compressor stage inlet temperature during the compression of crack gas. The lower inlet temperature of the compressor stage reduces its power demand and additionally, the discharge temperature remains in a suitable range. Applying the method of liquid injection, all injected droplets should be evaporated before entering the compressor impeller to avoid damage at the blades. A good knowledge about the evaporation process of injected liquid in a free stream is necessary to determine the required distance for complete evaporation of all droplets. The aim of this paper is to provide clear statements on technical possibilities and requirements for an optimized and reliable compression process under liquid injection. The evaporation process of injected hydrocarbon droplets into a gas stream is investigated under realistic boundary conditions. Using conservation laws of mass and energy, a 1D numerical model is derived which allows the calculation of the liquid hydrocarbon evaporation in a free stream. The required fluid properties are taken from the National Institute of Standards and Technology (NIST). A comparison between the 1D model and a 3D Navier-Stokes solution for injected CH 4 droplets into a CH 4 gas stream shows good agreement regarding the decrease of the droplet diameter during the evaporation with respect to the amount of injected mass of liquid fluid and gives a good indication of the requested distance for complete evaporation. In addition, the 1D model predicts the temperature decrease of the gas during evaporation in good accordance to a 3D Navier-Stokes solver. Applying the simple 1D model, it is possible to evaluate the thermodynamic inlet parameters of a compressor for given boundary conditions quickly. In addition, the results allow a statement regarding the complete evaporation of all sizes of injected droplets at the compressor inlet and the formation of liquid films at the walls

    Gas Kinematics on GMC scales in M51 with PAWS: cloud stabilization through dynamical pressure

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    We use the high spatial and spectral resolution of the PAWS CO(1-0) survey of the inner 9 kpc of the iconic spiral galaxy M51 to examine the effect of gas streaming motions on the star-forming properties of individual GMCs. We compare our view of gas flows in M51 -- which arise due to departures from axi-symmetry in the gravitational potential (i.e. the nuclear bar and spiral arms) -- with the global pattern of star formation as traced by Halpha and 24\mu m emission. We find that the dynamical environment of GMCs strongly affects their ability to form stars, in the sense that GMCs situated in regions with large streaming motions can be stabilized, while similarly massive GMCs in regions without streaming go on to efficiently form stars. We argue that this is the result of reduced surface pressure felt by clouds embedded in an ambient medium undergoing large streaming motions, which prevents collapse. Indeed, the variation in gas depletion time expected based on the observed streaming motions throughout the disk of M51 quantitatively agrees with the variation in observed gas depletion time scale. The example of M51 shows that streaming motions, triggered by gravitational instabilities in the form of bars and spiral arms, can alter the star formation law; this can explain the variation in gas depletion time among galaxies with different masses and morphologies. In particular, we can explain the long gas depletion times in spiral galaxies compared to dwarf galaxies and starbursts. We suggest that adding a dynamical pressure term to the canonical free-fall time produces a single star formation law that can be applied to all star-forming regions and galaxies, across cosmic time.Comment: 28 pages, 14 figures, accepted for publication in Ap

    The PdBI Arcsecond Whirlpool Survey (PAWS): Environmental Dependence of Giant Molecular Cloud Properties in M51

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    Using data from the PdBI Arcsecond Whirlpool Survey (PAWS), we have generated the largest extragalactic Giant Molecular Cloud (GMC) catalog to date, containing 1,507 individual objects. GMCs in the inner M51 disk account for only 54% of the total 12CO(1-0) luminosity of the survey, but on average they exhibit physical properties similar to Galactic GMCs. We do not find a strong correlation between the GMC size and velocity dispersion, and a simple virial analysis suggests that 30% of GMCs in M51 are unbound. We have analyzed the GMC properties within seven dynamically-motivated galactic environments, finding that GMCs in the spiral arms and in the central region are brighter and have higher velocity dispersions than inter-arm clouds. Globally, the GMC mass distribution does not follow a simple power law shape. Instead, we find that the shape of the mass distribution varies with galactic environment: the distribution is steeper in inter-arm region than in the spiral arms, and exhibits a sharp truncation at high masses for the nuclear bar region. We propose that the observed environmental variations in the GMC properties and mass distributions are a consequence of the combined action of large-scale dynamical processes and feedback from high mass star formation. We describe some challenges of using existing GMC identification techniques for decomposing the 12CO(1-0) emission in molecule-rich environments, such as M51's inner disk.Comment: 73 pages, 18 figures, 14 tables, accepted for publication in Ap

    The PdBI Arcsecond Whirlpool Survey (PAWS): Multi-phase cold gas kinematic of M51

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    The kinematic complexity and the favorable position of M51 on the sky make this galaxy an ideal target to test different theories of spiral arm dynamics. Taking advantage of the new high resolution PdBI Arcsecond Whirlpool Survey (PAWS) data, we undertake a detailed kinematic study of M51 to characterize and quantify the origin and nature of the non-circular motions. Using a tilted-ring analysis supported by several other archival datasets we update the estimation of M51's position angle (PA=(173 +/- 3) deg) and inclination (i=(22 +/- 5) deg). Harmonic decomposition of the high resolution (40 pc) CO velocity field shows the first kinematic evidence of an m=3 wave in the inner disk of M51 with a corotation at R(CR,m=3)=1.1 +/- 0.1 kpc and a pattern speed of Omega_p(m=3) = 140 km/(s kpc). This mode seems to be excited by the nuclear bar, while the beat frequencies generated by the coupling between the m=3 mode and the main spiral structure confirm its density-wave nature. We observe also a signature of an m=1 mode that is likely responsible for the lopsidedness of M51 at small and large radii. We provide a simple method to estimate the radial variation of the amplitude of the spiral perturbation (Vsp) attributed to the different modes. The main spiral arm structure has =50-70 km/s, while the streaming velocity associated with the m=1 and m=3 modes is, in general, 2 times lower. Our joint analysis of HI and CO velocity fields at low and high spatial resolution reveals that the atomic and molecular gas phases respond differently to the spiral perturbation due to their different vertical distribution and emission morphology.Comment: 42 pages, 12 figures, accepted for publication in Ap

    A Comparative Study of Giant Molecular Clouds in M51, M33 and the Large Magellanic Cloud

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    We compare the properties of giant molecular clouds (GMCs) in M51 identified by the Plateau de Bure Interferometer Whirlpool Arcsecond Survey (PAWS) with GMCs identified in wide-field, high resolution surveys of CO emission in M33 and the Large Magellanic Cloud (LMC). We find that GMCs in M51 are larger, brighter and have higher velocity dispersions relative to their size than equivalent structures in M33 and the LMC. These differences imply that there are genuine variations in the average mass surface density of the different GMC populations. To explain this, we propose that the pressure in the interstellar medium surrounding the GMCs plays a role in regulating their density and velocity dispersion. We find no evidence for a correlation between size and linewidth in any of M51, M33 or the LMC when the CO emission is decomposed into GMCs, although moderately robust correlations are apparent when regions of contiguous CO emission (with no size limitation) are used. Our work demonstrates that observational bias remains an important obstacle to the identification and study of extragalactic GMC populations using CO emission, especially in molecule-rich galactic environments.Comment: 25 pages, 11 figures, accepted for publication in ApJ. Uses emulateapj LaTeX macros. For more information on PAWS, further papers and data, see http://www.mpia.de/PAWS

    Copious Amounts of Dust and Gas in a z=7.5 Quasar Host Galaxy

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    We present IRAM/NOEMA and JVLA observations of the quasar J1342+0928 at z=7.54 and report detections of copious amounts of dust and [CII] emission in the interstellar medium (ISM) of its host galaxy. At this redshift, the age of the universe is 690 Myr, about 10% younger than the redshift of the previous quasar record holder. Yet, the ISM of this new quasar host galaxy is significantly enriched by metals, as evidenced by the detection of the [CII] 158micron cooling line and the underlying far-infrared (FIR) dust continuum emission. To the first order, the FIR properties of this quasar host are similar to those found at a slightly lower redshift (z~6), making this source by far the FIR-brightest galaxy known at z>7.5. The [CII] emission is spatially unresolved, with an upper limit on the diameter of 7 kpc. Together with the measured FWHM of the [CII] line, this yields a dynamical mass of the host of <1.5x10^11 M_sun. Using standard assumptions about the dust temperature and emissivity, the NOEMA measurements give a dust mass of (0.6-4.3)x10^8 M_sun. The brightness of the [CII] luminosity, together with the high dust mass, imply active ongoing star formation in the quasar host. Using [CII]-SFR scaling relations, we derive star formation rates of 85-545 M_sun/yr in the host, consistent with the values derived from the dust continuum. Indeed, an episode of such past high star formation is needed to explain the presence of ~10^8 M_sun of dust implied by the observations.Comment: 8 pages, 4 figures. Published in ApJ Letter
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