140 research outputs found

    Fabrication and Cold-Flow Testing of Subscale Space-Based Laser Geometry

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    The objectives of this research were to build a facility that could simulate the expected fluid flow properties in the conceptual Space Based Laser Integrated Flight Experiment (SBL IFX) gas dynamic laser using cold-flow, and to investigate the performance of the model. A 1/5th scale model was fabricated and mated to a blow-down/vacuum wind tunnel. Using rapid data acquisition and schlieren photography the diffuser was determined to initially produce similar fluid flow to the SBL IFX, but rapidly became subsonic due to a transient normal shock wave formed when the wind tunnel was started

    Sodium channel gene family: epilepsy mutations, gene interactions and modifier effects

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    The human sodium channel family includes seven neuronal channels that are essential for the initiation and propagation of action potentials in the CNS and PNS. In view of their critical role in neuronal firing and their strong sequence conservation during evolution, it is not surprising that mutations in the sodium channel genes are responsible for a growing spectrum of channelopathies. Nearly 700 mutations of the SCN1A gene have been identified in patients with Dravet's syndrome (severe myoclonic epilepsy of infancy), making this the most commonly mutated gene in human epilepsy. A small number of mutations have been found in SCN2A , SCN3A and SCN9A , and studies in the mouse suggest that SCN8A may also contribute to seizure disorders. Interactions between genetic variants of SCN2A and KCNQ2 in the mouse and variants of SCN1A and SCN9A in patients provide models of potential genetic modifier effects in the more common human polygenic epilepsies. New methods for generating induced pluripotent stem cells and neurons from patients will facilitate functional analysis of amino acid substitutions in channel proteins. Whole genome sequencing and exome sequencing in patients with epilepsy will soon make it possible to detect multiple variants and their interactions in the genomes of patients with seizure disorders.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/79388/1/jphysiol.2010.188482.pd

    Solid-State Protein Junctions:Cross-Laboratory Study Shows Preservation of Mechanism at Varying Electronic Coupling

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    Successful integration of proteins in solid-state electronics requires contacting them in a non-invasive fashion, with a solid conducting surface for immobilization as one such contact. The contacts can affect and even dominate the measured electronic transport. Often substrates, substrate treatments, protein immobilization, and device geometries differ between laboratories. Thus the question arises how far results from different laboratories and platforms are comparable and how to distinguish genuine protein electronic transport properties from platform-induced ones. We report a systematic comparison of electronic transport measurements between different laboratories, using all commonly used large-area schemes to contact a set of three proteins of largely different types. Altogether we study eight different combinations of molecular junction configurations, designed so that Ageo of junctions varies from 105 to 10−3 μm2. Although for the same protein, measured with similar device geometry, results compare reasonably well, there are significant differences in current densities (an intensive variable) between different device geometries. Likely, these originate in the critical contact-protein coupling (∼contact resistance), in addition to the actual number of proteins involved, because the effective junction contact area depends on the nanometric roughness of the electrodes and at times, even the proteins may increase this roughness. On the positive side, our results show that understanding what controls the coupling can make the coupling a design knob. In terms of extensive variables, such as temperature, our comparison unanimously shows the transport to be independent of temperature for all studied configurations and proteins. Our study places coupling and lack of temperature activation as key aspects to be considered in both modeling and practice of protein electronic transport experiments

    Review of particle physics

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    This biennial Review summarizes much of particle physics. Using data from previous editions, plus 2658 new measurements from 644 papers, we list, evaluate, and average measured properties of gauge bosons, leptons, quarks, mesons, and baryons. We summarize searches for hypothetical particles such as Higgs bosons, heavy neutrinos, and supersymmetric particles. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and reviews of topics such as the Standard Model, particle detectors, probability, and statistics. Among the 112 reviews are many that are new or heavily revised including those on Heavy-Quark and Soft-Collinear Effective Theory, Neutrino Cross Section Measurements, Monte Carlo Event Generators, Lattice QCD, Heavy Quarkonium Spectroscopy, Top Quark, Dark Matter, Vcb& Vub, Quantum Chromodynamics, High-Energy Collider Parameters, Astrophysical Constants, Cosmological Parameters, and Dark Matter. A booklet is available containing the Summary Tables and abbreviated versions of some of the other sections of this full Review. All tables, listings, and reviews (and errata) are also available on the Particle Data Group website: http://pdg.lbl.gov/. The 2012 edition of Review of Particle Physics is published for the Particle Data Group as article 010001 in volume 86 of Physical Review D. This edition should be cited as: J. Beringer et al. (Particle Data Group), Phys. Rev. D 86, 010001 (2012). © 2012 Regents of the University of California

    Role of the tachykinin NK1 receptor in a murine model of cigarette smoke-induced pulmonary inflammation

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    <p>Abstract</p> <p>Background</p> <p>The tachykinins, substance P and neurokinin A, present in sensory nerves and inflammatory cells such as macrophages and dendritic cells, are considered as pro-inflammatory agents. Inflammation of the airways and lung parenchyma plays a major role in the pathogenesis of chronic obstructive pulmonary disease (COPD) and increased tachykinin levels are recovered from the airways of COPD patients. The aim of our study was to clarify the involvement of the tachykinin NK<sub>1 </sub>receptor, the preferential receptor for substance P, in cigarette smoke (CS)-induced pulmonary inflammation and emphysema in a mouse model of COPD.</p> <p>Methods</p> <p>Tachykinin NK<sub>1 </sub>receptor knockout (NK<sub>1</sub>-R<sup>-/-</sup>) mice and their wild type controls (all in a mixed 129/sv-C57BL/6 background) were subjected to sub acute (4 weeks) or chronic (24 weeks) exposure to air or CS. 24 hours after the last exposure, pulmonary inflammation and development of emphysema were evaluated.</p> <p>Results</p> <p>Sub acute and chronic exposure to CS resulted in a substantial accumulation of inflammatory cells in the airways of both WT and NK<sub>1</sub>-R<sup>-/- </sup>mice. However, the CS-induced increase in macrophages and dendritic cells was significantly impaired in NK<sub>1</sub>-R<sup>-/- </sup>mice, compared to WT controls, and correlated with an attenuated release of MIP-3α/CCL20 and TGF-β1. Chronic exposure to CS resulted in development of pulmonary emphysema in WT mice. NK<sub>1</sub>-R<sup>-/- </sup>mice showed already enlarged airspaces upon air-exposure. Upon CS-exposure, the NK<sub>1</sub>-R<sup>-/- </sup>mice did not develop additional destruction of the lung parenchyma. Moreover, an impaired production of MMP-12 by alveolar macrophages upon CS-exposure was observed in these KO mice. In a pharmacological validation experiment using the NK<sub>1 </sub>receptor antagonist RP 67580, we confirmed the protective effect of absence of the NK<sub>1 </sub>receptor on CS-induced pulmonary inflammation.</p> <p>Conclusion</p> <p>These data suggest that the tachykinin NK<sub>1 </sub>receptor is involved in the accumulation of macrophages and dendritic cells in the airways upon CS-exposure and in the development of smoking-induced emphysema. As both inflammation of the airways and parenchymal destruction are important characteristics of COPD, these findings may have implications in the future treatment of this devastating disease.</p

    Mouse models to unravel the role of inhaled pollutants on allergic sensitization and airway inflammation

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    Air pollutant exposure has been linked to a rise in wheezing illnesses. Clinical data highlight that exposure to mainstream tobacco smoke (MS) and environmental tobacco smoke (ETS) as well as exposure to diesel exhaust particles (DEP) could promote allergic sensitization or aggravate symptoms of asthma, suggesting a role for these inhaled pollutants in the pathogenesis of asthma. Mouse models are a valuable tool to study the potential effects of these pollutants in the pathogenesis of asthma, with the opportunity to investigate their impact during processes leading to sensitization, acute inflammation and chronic disease. Mice allow us to perform mechanistic studies and to evaluate the importance of specific cell types in asthma pathogenesis. In this review, the major clinical effects of tobacco smoke and diesel exhaust exposure regarding to asthma development and progression are described. Clinical data are compared with findings from murine models of asthma and inhalable pollutant exposure. Moreover, the potential mechanisms by which both pollutants could aggravate asthma are discussed

    Review of Particle Physics (2010)

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    A booklet is available containing the Summary Tables and abbreviated versions of some of the other sections of this full Review. All tables, listings, and reviews (and errata) are also available on the Particle Data Group website: pdg.lbl.gov.This biennial Review summarizes much of particle physics. Using data from previous editions, plus 2158 new measurements from 551 papers, we list, evaluate, and average measured properties of gauge bosons, leptons, quarks, mesons, and baryons. We also summarize searches for hypothetical particles such as Higgs bosons, heavy neutrinos, and supersymmetric particles. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and reviews of topics such as the Standard Model, particle detectors, probability, and statistics. Among the 108 reviews are many that are new or heavily revised including those on neutrino mass, mixing, and oscillations, QCD, top quark, CKM quark-mixing matrix, Vud & Vus, Vcb & Vub, fragmentation functions, particle detectors for accelerator and non-accelerator physics, magnetic monopoles, cosmological parameters, and big bang cosmology.MICINN, Spain (FPA2009-07264-E). The publication of the Review of Particle Physics is supported by the Director, Office of Science, Office of High Energy and Nuclear Physics, the Division of High Energy Physics of the U.S. Department of Energy under Contract No. DE–AC02–05CH11231; by the U.S. National Science Foundation under Agreement No. PHY-0652989; by the European Laboratory for Particle Physics (CERN); by an implementing arrangement between the governments of Japan (MEXT: Ministry of Education, Culture, Sports, Science and Technology) and the United States (DOE) on cooperative research and development; and by the Italian National Institute of Nuclear Physics (INFN)

    The relationship of university press inventory evaluation to management decisions

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    Includes bibliographical references.Problem. Inventory evaluation of university presses had not evolved into one accepted method. It was the purpose of this study to compare several methods used to evaluate inventory and ascertain their relationship to various management functions. The following hypotheses were formulated: 1. Over a period of fifteen years there is a significant difference in total net sales resulting from the use of any of the six different methods of inventory evaluation. 2. There will be a positive coefficient of correlation between net sales and cash flow in each of the different methods of inventory evaluation. 3. There will be a positive coefficient of correlation between recorded inventory value and inventory value computed by multiplying physical count by a per volume value which reflects all assignable costs. Procedures for this study were as follows: 1. Operating data for a hypothetical university press were devised from A.A.U.A., U.P.S. statistical report along with patterns developed by experts. 2. Operating statements for fifteen years were devised for each of six inventory evaluation methods. 3. The results of the six methods along with cash flow need of the manufacturing operation and the inventory values at cost for each of the fifteen years were summarized. 4. The summarized data were statistically analyzed. Findings and Conclusions The first hypothesis was rejected with reservation. The second and third were both accepted with a large significance probability. The following conclusions were made: 1. The correlation coefficient between net sales and cash flow was highest in the method which assigned an early write off in the years of greatest cash flow needs. 2. The correlation coefficient between recorded inventory and inventory value was highest in the methods which did not record inventory write off expense directly to the inventory account. 3. Because of the long term rate of inventory turnover there is a need for further study of funding methods.M.S. (Master of Science

    Panorama view of Two Harbors, Minn.

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    Copyright deposit; Carl E. Bergren; September 1, 1917
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