Science.gov

Sample records for 8-ft-diameter barrel test

  1. Design of 8-ft-Diameter Barrel Test Article Attachment Rings for Shell Buckling Knockdown Factor Project

    NASA Technical Reports Server (NTRS)

    Lovejoy, Andrew E.; Hilburger, Mark W.

    2010-01-01

    The Shell Buckling Knockdown Factor (SBKF) project includes the testing of sub-scale cylinders to validate new shell buckling knockdown factors for use in the design of the Ares-I and Ares-V launch vehicles. Test article cylinders represent various barrel segments of the Ares-I and Ares-V vehicles, and also include checkout test articles. Testing will be conducted at Marshall Space Flight Center (MSFC) for test articles having an eight-foot diameter outer mold line (OML) and having lengths that range from three to ten feet long. Both ends of the test articles will be connected to the test apparatus using attachment rings. Three multiple-piece and one single-piece design for the attachment rings were developed and analyzed. The single-piece design was chosen and will be fabricated from either steel or aluminum (Al) depending on the required safety factors (SF) for test hardware. This report summarizes the design and analysis of these attachment ring concepts.

  2. First testing of the CALIFA Barrel Demonstrator

    NASA Astrophysics Data System (ADS)

    Pietras, B.; Winkel, M.; Alvarez-Pol, H.; Bendel, M.; Casarejos, E.; Cederkäll, J.; Cortina-Gil, D.; Fernandez, G.; Gernhäuser, R.; Golubev, P.; González, D.; Hartig, A.; Izquierdo, P.; Klenze, P.; Le Bleis, T.; Nácher, E.; Perea, A.; Remmels, P.; Ribeiro, G.; Teubig, P.; Vilan, J.; Yañez, P.

    2016-04-01

    Advancement of the CALIFA calorimeter project has reached a new milestone with the construction of the first modules of the CALIFA Demonstrator, ultimately to be integrated into the final calorimeter. Aspects and methods of detector optimisation will be discussed, along with characterisation using proton beams of 70 test of each component's performance. A study of caesium iodide quenching over the available proton energy range has been performed, to accompany a method for proton calibration scaled from the measured gamma-ray energies.

  3. 49 CFR 178.607 - Cooperage test for bung-type wooden barrels.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... FOR PACKAGINGS Testing of Non-bulk Packagings and Packages § 178.607 Cooperage test for bung-type wooden barrels. (a) Number of samples. One barrel is required for each different packaging. (b) Method of... 49 Transportation 2 2010-10-01 2010-10-01 false Cooperage test for bung-type wooden barrels....

  4. The Common Cryogenic Test Facility for the ATLAS Barrel and End-Cap Toroid Magnets

    SciTech Connect

    Delruelle, N.; Haug, F.; Junker, S.; Passardi, G.; Pengo, R.; Pirotte, O.

    2004-06-23

    The large ATLAS toroidal superconducting magnet made of the Barrel and two End-Caps needs extensive testing at the surface of the individual components prior to their final assembly into the underground cavern of LHC. A cryogenic test facility specifically designed for cooling sequentially the eight coils making the Barrel Toroid (BT) has been fully commissioned and is now ready for final acceptance of these magnets. This facility, originally designed for testing individually the 46 tons BT coils, will be upgraded to allow the acceptance tests of the two End-Caps, each of them having a 160 tons cold mass. The integrated system mainly comprises a 1.2 kW at 4.5 K refrigerator, a 10 kW liquid-nitrogen precooler, two cryostats housing liquid helium centrifugal pumps of respectively 80 g/s and 600 g/s nominal flow and specific instrumentation to measure the thermal performances of the magnets. This paper describes the overall facility with particular emphasis to the cryogenic features adopted to match the specific requirements of the magnets in the various operating scenarios.

  5. Preliminary results from the multishot opening switch and barrel testing at ARDC

    NASA Astrophysics Data System (ADS)

    Berg, R.; Breitenstein, A.; Carr, S.; Coffman, L.; Cook, H.

    1986-11-01

    Design features and test data are summarized for a multishot switch and barrel of an electromagnetic launch system which has undergone trials at the Armament R&D Center (ARDC). The system features a 12 MJ homopolar generator, a 4.5 micro-H storage inductor and two circularly mounted parallel copper conductors separated by 2.5 cm. Tests focused on the performance of the opening switch with currents up to 500 kA. THe effects of the tests on the condition of the brush and on the operation of the switch are delineated, noting the deformations induced on the brush fingers by magnetic pressure, reducing contact force when the brush was in the input region of the switch. Design changes being implemented to alleviate the problem are outlined.

  6. Barrels XXIX: Barrels go Hollywood.

    PubMed

    Evans, Mathew H; Brumberg, Joshua C

    2017-03-01

    Barrels XXIX brought together researchers focusing on the rodent barrel cortex and associated systems. The meeting revolved around three themes: thalamocortical interactions in motor control, touch in rodent, monkey, and humans, and the nature of the multisensory computations the brain makes. Over two days these topics were covered as well as many more presentations that focused on the physiology, behavior, and development of the rodent whisker-to-barrel cortex system.

  7. Cooling Tests of an Air-Cooled Engine Cylinder with Copper Fins on the Barrel

    DTIC Science & Technology

    1942-07-01

    of the piston thermo- couples aro shown in figures 3 and 4. The locations of the cylinder-surface tiernocc-~ples are shown In figure 5. The crankshaft ...the =esult of improvsd fin design shows that the outside barrel temperature may be a poor crite- rion for barrel cooling. ~or example, at 0.7...dimensions in the L . aluminum-muff design Is reetrieted by limits imposed In maohiriing the fins. With aluminum fins, ae with copper fins, the fin

  8. The Fabrication and Testing of Glass Matrix Composite Cylinders for Gun Barrel Liner Applications

    DTIC Science & Technology

    1982-02-01

    completely seal the com- posite from the HIP gas environment. Metal HIP Containers - The use of a stainless steel metal envelope is another approach to...catastrophic failure was exhibited. INTRODUCTION AND BACKGROUND Current state-of-the-art gun barrels are fabricated from stellite lined chrome...plated steel tubes. Due to their high percentage of the critical ele- ments cobalt and chromium, they are becoming increasingly expensive to manu

  9. Boron Nanotubes/Nanofibers in Propellant Material Formulations: Testing and Characterization for Gun Barrel Protection

    DTIC Science & Technology

    2011-01-13

    GFS Chemicals) powder as the primary catalyst, and mesostructured hexagonal framework MCM- 41(Sigma Aldrich) zeolite powder as the template for guiding...the MCM-41 zeolite is evident in the left image. The image on the right shows that nearly all the MCM-41 is removed from the sample. 3...during propellant firing to protect gun barrel surfaces. Also since the nitrogen doped nanostructures remain highly electrically and thermally

  10. Field Developmental Test of the Dual Barrel Automatic Injector, MARK II.

    DTIC Science & Technology

    1986-04-01

    criteria OCCURRENCE - a detected event 2-PAM-CL BARREL - the larger black-tipped cylinder contained within the autoinjector housing SAFETY PIN - the...yellow plastic protrusion from the safety cap which prevents injector activation SAFETY SCREW - the metal screw which attaches the safety pin to the...2 0 0 (1.1) (1.0) loose safety pin 164 27 10 13 (11.0) (10.7) (18.8) (21.7) NO DEFECTS NOTED 1184 209 42 35 (76.5) (82.9) (70.0) (58.0) UNKNOWN

  11. OPTIMIZING CENTRIFUGAL BARREL POLISHING FOR MIRROR FINISH SRF CAVITY AND RF TESTS AT JEFFERSON LAB

    SciTech Connect

    Ari Palczewski, Rongli Geng, Hui Tian

    2012-07-01

    We performed Centrifugal Barrel Polishing (CBP) on a 1.3 GHz fine grain TESLA single cell cavity and 1.5 GHz fine grain CEBAF high gradient superconducting radio frequency (SRF) single cell cavity following a modified recipe originally developed at Fermi National Accelerator Lab (FNAL). We were able to obtain a mirror like surface similar to that obtained at FNAL, while reducing the number of CBP steps and total processing time. This paper will discuss the change in surface and subsequent cavity performance post CBP, after a 800 C bake (no pre-bake chemistry) and minimal controlled electro-polishing (10 micron). In addition to Q vs. E{sub ACC} thermometry mapping with preheating characteristics and optical inspection of the cavity after CBP will also be shown.

  12. Development of an advanced electromagnetic gun barrel

    NASA Astrophysics Data System (ADS)

    Hurn, T. W.; D'Aoust, J.; Sevier, L.; Johnson, R.; Wesley, J.

    1993-01-01

    An advanced EM gun (AEMG) barrel was developed for the USAF Wright Laboratory to repetitively accelerate large-mass projectiles. The AEMG barrel employed 5-m rails, had a 50 mm square bore, and was designed to operate at a peak current of 1.5 MA (bore pressure 25 ksi). Key technical achievements included (1) an efficient barrel containment structure that weighs approximately 25 percent of a similarly rated clamped barrel, (2) an insulator material that retains surface resistivity after repeated firings, and (3) a high-velocity water cooling system designed to remove a peak heat flux of 5 MJ/sq m per shot. The AEMG barrel's thermal management system employed a 500 psi blowdown system that generated high velocity coolant flow rates in five axial coolant channels within each rail. Innovative fabrication processes were used to develop the barrel. A 2-m prototype of the AEMG barrel was tested in the General Atomics 4 MJ EM launcher test facility.

  13. Clean fog rapid procedure test of artificially and naturally polluted HVDC porcelain barrel insulators

    SciTech Connect

    Vlastos, A.E. )

    1992-07-01

    The first question asked in this paper refers to the variation of the peak leakage current prior to the flashover and the variation of the time prior to flashover in the test of artificially polluted insulators when using the up-and-down method. To answer this question sums up the test procedure used in the up-and-down method. For each trial represented the insulator was again polluted artificially and then dried following the procedure described in the paper. Then the insulator was transported into the fog chamber and the voltage and fog was switched on simultaneously. In these experiments a low fog injection rate was used.

  14. Radiation Hardness Tests of SiPMs for the JLab Hall D Barrel Calorimeter

    SciTech Connect

    Yi Qiang, Carl Zorn, Fernando Barbosa, Elton Smith

    2013-01-01

    We report on the measurement of the neutron radiation hardness of silicon photomultipliers (SiPMs) manufactured by Hamamatsu Corporation in Japan and SensL in Ireland. Samples from both companies were irradiated by neutrons created by a 1 GeV electron beam hitting a thin lead target at Jefferson Lab Hall A. More tests regarding the temperature dependence of the neutron radiation damage and self-annealing were performed on Hamamatsu SiPMs using a calibrated Am–Be neutron source from the Jefferson Lab Radiation Control group. As the result of irradiation both dark current and dark rate increase linearly as a function of the 1 MeV equivalent neutron fluence and a temperature dependent self-annealing effect is observed

  15. Buckling Testing and Analysis of Honeycomb Sandwich Panel Arc Segments of a Full-Scale Fairing Barrel: Comparison of In- and Out-of-Autoclave Facesheet Configurations

    NASA Technical Reports Server (NTRS)

    Pineda, Evan Jorge; Myers, David E.; Kosareo, Daniel N.; Zalewski, Bart F.; Kellas, Sotiris; Dixon, Genevieve D.; Krivanek, Thomas M.; Gyekenyesi, Thomas G.

    2014-01-01

    Four honeycomb sandwich panels, representing 1/16th arc segments of a 10-m diameter barrel section of the Heavy Lift Launch Vehicle, were manufactured and tested under the NASA Composites for Exploration and the NASA Constellation Ares V programs. Two configurations were chosen for the panels: 6-ply facesheets with 1.125 in. honeycomb core and 8-ply facesheets with 1.0 in. honeycomb core. Additionally, two separate carbon fiber/epoxy material systems were chosen for the facesheets: in-autoclave IM7/977-3 and out-of-autoclave T40-800b/5320-1. Smaller 3 ft. by 5 ft. panels were cut from the 1/16th barrel sections and tested under compressive loading. Furthermore, linear eigenvalue and geometrically nonlinear finite element analyses were performed to predict the compressive response of each 3 ft. by 5 ft. panel. To improve the robustness of the geometrically nonlinear finite element model, measured surface imperfections were included in the geometry of the model. Both the linear and nonlinear models yielded good qualitative and quantitative predictions. Additionally, it was correctly predicted that the panel would fail in buckling prior to failing in strength. Furthermore, several imperfection studies were performed to investigate the influence of geometric imperfections, fiber angle misalignments, and three-dimensional effects on the compressive response of the panel.

  16. Buckling Testing and Analysis of Honeycomb Sandwich Panel Arc Segments of a Full-Scale Fairing Barrel. Part 3; 8-ply Out-of-Autoclave Facesheets

    NASA Technical Reports Server (NTRS)

    Pineda, Evan J.; Myers, David E.; Kosareo, Daniel N.; Kellas, Sotiris

    2014-01-01

    Four honeycomb sandwich panels, representing 1/16th arc segments of a 10 m diameter barrel section of the heavy lift launch vehicle, were manufactured under the NASA Composites for Exploration program and the NASA Constellation Ares V program. Two configurations were chosen for the panels: 6-ply facesheets with 1.125 in. honeycomb core and 8-ply facesheets with 1.000 in. honeycomb core. Additionally, two separate carbon fiber/epoxy material systems were chosen for the facesheets: inautoclave IM7/977-3 and out-of-autoclave T40-800B/5320-1. Smaller 3- by 5-ft panels were cut from the 1/16th barrel sections. These panels were tested under compressive loading at the NASA Langley Research Center. Furthermore, linear eigenvalue and geometrically nonlinear finite element analyses were performed to predict the compressive response of the 3- by 5-ft panels. This manuscript summarizes the experimental and analytical modeling efforts pertaining to the panel composed of 8-ply, T40-800B/5320-1 facesheets (referred to as Panel C). To improve the robustness of the geometrically nonlinear finite element model, measured surface imperfections were included in the geometry of the model. Both the linear and nonlinear, two-dimensional (2-D) and three-dimensional (3-D), models yield good qualitative and quantitative predictions. Additionally, it was predicted correctly that the panel would fail in buckling prior to failing in strength.

  17. The PANDA Barrel DIRC

    NASA Astrophysics Data System (ADS)

    Dzhygadlo, R.; Schwarz, C.; Belias, A.; Gerhardt, A.; Götzen, K.; Kalicy, G.; Krebs, M.; Lehmann, D.; Nerling, F.; Patsyuk, M.; Peters, K.; Schepers, G.; Schmitt, L.; Schwiening, J.; Traxler, M.; Zühlsdorf, M.; Britting, A.; Eyrich, W.; Lehmann, A.; Pfaffinger, M.; Uhlig, F.; Düren, M.; Etzelmüller, E.; Föhl, K.; Hayrapetyan, A.; Kröck, B.; Merle, O.; Rieke, J.; Schmidt, M.; Cowie, E.; Keri, T.; Achenbach, P.; Cardinali, M.; Hoek, M.; Lauth, W.; Schlimme, S.; Sfienti, C.; Thiel, M.

    2016-05-01

    The PANDA detector at the international accelerator Facility for Antiproton and Ion Research in Europe (FAIR) addresses fundamental questions of hadron physics. Experiments concerning charmonium spectroscopy, the search for hybrids and glueballs and the interaction of hidden and open charm particles with nucleons and nuclei will be performed with antiproton beams impinging on hydrogen or nuclear targets. Cooled beams allow the precision scan of resonances in formation experiments. The momentum range of the antiproton beam between 1.5 GeV/c and 15 GeV/c tests predictions by perturbation theory and will reveal deviations originating from strong QCD . An excellent hadronic particle identification will be accomplished by DIRC (Detection of Internally Reflected Cherenkov light) counters. The design for the barrel region is based on the successful BaBar DIRC with several key improvements, such as fast photon timing and a compact imaging region. DIRC designs based on different radiator geometries with several focusing options were studied in simulation. The performance of each design was characterized in terms of photon yield and single photon Cherenkov angle resolution. Selected design options were implemented in prototypes and tested with hadronic particle beams at GSI and CERN.

  18. Buckling Testing and Analysis of Honeycomb Sandwich Panel Arc Segments of a Full-Scale Fairing Barrel. Part 2; 6-Ply In-Autoclave Facesheets

    NASA Technical Reports Server (NTRS)

    Pineda, Evan J.; Meyers, David E.; Kosareo, Daniel N.; Zalewski, Bart F.; Dixon, Genevieve D.

    2013-01-01

    Four honeycomb sandwich panel types, representing 1/16th arc segments of a 10-m diameter barrel section of the Heavy Lift Launch Vehicle (HLLV), were manufactured and tested under the NASA Composites for Exploration program and the NASA Constellation Ares V program. Two configurations were chosen for the panels: 6-ply facesheets with 1.125 in. honeycomb core and 8-ply facesheets with 1.000 in. honeycomb core. Additionally, two separate carbon fiber/epoxy material systems were chosen for the facesheets: in-autoclave IM7/977-3 and out-of-autoclave T40-800b/5320-1. Smaller 3- by 5-ft panels were cut from the 1/16th barrel sections. These panels were tested under compressive loading at the NASA Langley Research Center (LaRC). Furthermore, linear eigenvalue and geometrically nonlinear finite element analyses were performed to predict the compressive response of each 3- by 5-ft panel. This manuscript summarizes the experimental and analytical modeling efforts pertaining to the panels composed of 6-ply, IM7/977-3 facesheets (referred to as Panels B-1 and B-2). To improve the robustness of the geometrically nonlinear finite element model, measured surface imperfections were included in the geometry of the model. Both the linear and nonlinear models yield good qualitative and quantitative predictions. Additionally, it was correctly predicted that the panel would fail in buckling prior to failing in strength. Furthermore, several imperfection studies were performed to investigate the influence of geometric imperfections, fiber angle misalignments, and three-dimensional (3-D) effects on the compressive response of the panel.

  19. Multi-rail barrel design and performance

    NASA Astrophysics Data System (ADS)

    Maas, Brian L.; Bauer, David P.; Challita, Antonios

    1993-01-01

    Railgun barrels containing multiple isolated rail pairs can be used to control armature current distribution and/or to obtain independent circuits for use with specialized power supplies. Armature current control can be used to effectively distribute acceleration forces for improved projectile launch. Independent rail 'load' circuits are attractive for use with some power supplies such as a polyphase compulsator. We have built and tested a 30 mm barrel containing three distinct rail pairs. These three rail pairs were powered by separate power supplies. This paper describes issues associated with multi-rail barrel design and our band design and performance. Rail alignment, isolation, and construction are described. The effect of multiple rail pairs on the effective inductance gradient of the band is described and test results are provided.

  20. BARREL Team Launching 20 Balloons

    NASA Video Gallery

    A movie made by the NASA-Funded Balloon Array for Radiation belt Relativistic Electron Losses, or BARREL, team on their work launching 20 balloons in Antarctica during the Dec. 2013/Jan. 2014 campa...

  1. Variant M4 Barrel Characterization

    DTIC Science & Technology

    2009-07-01

    an Instron Wilson-Tukon micro hardness - tester using a Knoop indenter with a 200g load. Knoop hardness values where then converted to 3 Rockwell ...relatively thin and localized to wide cracks and surfaces where the chromium has been completely removed. All fired barrels show extensive copper ...barrels had large deposits of copper at the root of the lands; in addition to collecting copper and firing debris at surface cracks and disparities

  2. OSIRIS camera barrel optomechanical design

    NASA Astrophysics Data System (ADS)

    Farah, Alejandro; Tejada, Carlos; Gonzalez, Jesus; Cobos, Francisco J.; Sanchez, Beatriz; Fuentes, Javier; Ruiz, Elfego

    2004-09-01

    A Camera Barrel, located in the OSIRIS imager/spectrograph for the Gran Telescopio Canarias (GTC), is described in this article. The barrel design has been developed by the Institute for Astronomy of the University of Mexico (IA-UNAM), in collaboration with the Institute for Astrophysics of Canarias (IAC), Spain. The barrel is being manufactured by the Engineering Center for Industrial Development (CIDESI) at Queretaro, Mexico. The Camera Barrel includes a set of eight lenses (three doublets and two singlets), with their respective supports and cells, as well as two subsystems: the Focusing Unit, which is a mechanism that modifies the first doublet relative position; and the Passive Displacement Unit (PDU), which uses the third doublet as thermal compensator to maintain the camera focal length and image quality when the ambient temperature changes. This article includes a brief description of the scientific instrument; describes the design criteria related with performance justification; and summarizes the specifications related with misalignment errors and generated stresses. The Camera Barrel components are described and analytical calculations, FEA simulations and error budgets are also included.

  3. Superior Barrel & Drum, Elk Township, New Jersey

    EPA Pesticide Factsheets

    The Superior Barrel and Drum Superfund site is a 5.5-acre property located in Elk Township, Gloucester County, New Jersey. Superior Barrel and Drum is listed as a drum reconditioning business. These facilities typically clean and recondition metal

  4. Use of Electroplated Chromium in Gun Barrels

    DTIC Science & Technology

    2006-05-01

    Temperature; oF S t r e s s R e t a i n e d ; % 50% swage 75% swage Residual stress retained following 2 hr furnace heating of 120mm M256 gun barrels... Swage Autofrettage LARGE CALIBER GUN BARREL STRENGTH Coating Process Temperature Limitations Autofrettage allows gun barrels to be lighter and

  5. Drag Measurements of a Protruding .50-caliber Machine Gun with Barrel Jacket Removed

    NASA Technical Reports Server (NTRS)

    Luoma, Arvo A.

    1943-01-01

    Tests were made in 8-ft high-speed wind tunnel to determine the drag reduction possible by eliminating the barrel jacket of a protruding 50-caliber aircraft gun. It was found that the drag of a standard aircraft gun protruding into the air stream at right angles to the flow can be reduced by 23% by discarding the barrel jacket. At 300 mph and sea-level conditions, this amounts to a decrease in drag of from 83 to 64 pounds. A rough surface finish on the barrel was found to have no adverse effects on the drag of the barrel, the drag being actually less at high Mach Numbers.

  6. 15 CFR 241.2 - Legal standard barrels.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ..., VEGETABLES AND OTHER DRY COMMODITIES, AND FOR CRANBERRIES § 241.2 Legal standard barrels. (a) Any barrel..., other than cranberries, in section 1 of the standard-barrel law, or any barrel or a subdivision thereof... than cranberries, or a legal subdivision thereof. No other barrel or subdivision in barrel form is...

  7. 15 CFR 241.2 - Legal standard barrels.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ..., VEGETABLES AND OTHER DRY COMMODITIES, AND FOR CRANBERRIES § 241.2 Legal standard barrels. (a) Any barrel..., other than cranberries, in section 1 of the standard-barrel law, or any barrel or a subdivision thereof... than cranberries, or a legal subdivision thereof. No other barrel or subdivision in barrel form is...

  8. 15 CFR 241.2 - Legal standard barrels.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ..., VEGETABLES AND OTHER DRY COMMODITIES, AND FOR CRANBERRIES § 241.2 Legal standard barrels. (a) Any barrel..., other than cranberries, in section 1 of the standard-barrel law, or any barrel or a subdivision thereof... than cranberries, or a legal subdivision thereof. No other barrel or subdivision in barrel form is...

  9. 15 CFR 241.2 - Legal standard barrels.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ..., VEGETABLES AND OTHER DRY COMMODITIES, AND FOR CRANBERRIES § 241.2 Legal standard barrels. (a) Any barrel..., other than cranberries, in section 1 of the standard-barrel law, or any barrel or a subdivision thereof... than cranberries, or a legal subdivision thereof. No other barrel or subdivision in barrel form is...

  10. 15 CFR 241.2 - Legal standard barrels.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ..., VEGETABLES AND OTHER DRY COMMODITIES, AND FOR CRANBERRIES § 241.2 Legal standard barrels. (a) Any barrel..., other than cranberries, in section 1 of the standard-barrel law, or any barrel or a subdivision thereof... than cranberries, or a legal subdivision thereof. No other barrel or subdivision in barrel form is...

  11. Buckling Testing and Analysis of Honeycomb Sandwich Panel Arc Segments of a Full-Scale Fairing Barrel Part 1: 8-Ply In-Autoclave Facesheets. Part 1; 8-Ply In-Autoclave Facesheets

    NASA Technical Reports Server (NTRS)

    Myers, David E.; Pineda, Evan J.; Zalewski, Bart F.; Kosareo, Daniel N.; Kellas, Sotiris

    2013-01-01

    Four honeycomb sandwich panels, representing 1/16th arc segments of a 10-m diameter barrel section of the heavy lift launch vehicle, were manufactured under the NASA Composites for Exploration program and the NASA Space Launch Systems program. Two configurations were chosen for the panels: 6-ply facesheets with 1.125 in. honeycomb core and 8-ply facesheets with 1.000 in. honeycomb core. Additionally, two separate carbon fiber/epoxy material systems were chosen for the facesheets: inautoclave IM7/977-3 and out-of-autoclave T40-800b/5320-1. Smaller 3.00- by 5.00-ft panels were cut from the 1/16th barrel sections. These panels were tested under compressive loading at the NASA Langley Research Center. Furthermore, linear eigenvalue and geometrically nonlinear finite element analysis was performed to predict the compressive response of the 3.00- by 5.00-ft panels. This manuscript summarizes the experimental and analytical modeling efforts pertaining to the panel composed of 8-ply, IM7/977-3 facesheets (referred to Panel A). To improve the robustness of the geometrically nonlinear finite element model, measured surface imperfections were included in the geometry of the model. Both the linear and nonlinear models yield good qualitative and quantitative predictions. Additionally, it was predicted correctly that the panel would fail in buckling prior to failing in strength. Furthermore, several imperfection studies were performed to investigate the influence of geometric imperfections, fiber misalignments, and three-dimensional (3 D) effects on the compressive response of the panel.

  12. Calibration and operation of the PNL Barrel Assayer

    SciTech Connect

    Arthur, R J

    1991-07-01

    Pacific Northwest Laboratory operates a Barrel Assayer to measure the radionuclide content of 208-liter waste drums. This mobile apparatus is designed to provide quantitative information on each radioisotope in a drum and to recognize and locate hot spots within the drum. A lead-collimated intrinsic-germanium detector mounted on a moveable platform vertically scans a rotating drum for gamma-ray activity while 62 stationary {sup 10}BF{sub 3} tubes measure neutrons emitted by transuranic isotopes within the waste. Several approaches have been used to document the controls under which the Barrel Assayer has been operated from February 1989 through December 1990. Resin-filled 208-1 calibration barrels containing known quantities of {sup 60}Co, {sup 137}Cs, and {sup 134}Cs were measured by the Barrel Assayer and found to be well within 25% of the known values. A thorium nitrate standard that served as the secondary, or field, standard verified that the detector has been within calibration during the period from February 1989 through December 1990. In previous testing, 23 waste drums were assayed at several commercial nuclear power plants. Subsequently, aliquots from the top, middle, and bottom of the barrels were analyzed. The ratio of grab-sample concentration to direct-assay concentration averaged {minus}1.6 for one plant and +1.3 for another. Results using the Barrel Assayer were also comparable to those obtained using Safeguards Security's Segmented Gamma-ray Scanner (SGS) system in a cross-calibration experiment performed by a third party on several drums containing TRU wastes. 6 refs., 6 figs., 9 tabs.

  13. Postsynaptic Deregulation in GAP-43 Heterozygous Mouse Barrel Cortex

    PubMed Central

    Kelly, Emily A.; Tremblay, Marie-Ève; McCasland, James S.

    2010-01-01

    Formation of whisker-related barrels in primary somatosensory cortex (S1) requires communication between presynaptic thalamocortical afferents (TCAs) and postsynaptic cortical neurons. GAP-43 is crucially involved in targeting TCAs to postsynaptic S1 neurons but its influence on the interactions between these 2 elements has not been explored. Here, we tested the hypothesis that reduced early expression of presynaptic GAP-43 (GAP-43 heterozygous [HZ] mice) alters postsynaptic differentiation of barrel cells. We found a transient increase in cytochrome oxidase staining between P6 and P14 in HZ animals, indicative of increased metabolic activity in barrel cortex during this time. Golgi impregnation and microtubule-associated protein 2 immunohistochemistry showed anomalous dendritic patterning in GAP-43 HZ cortex at P5, with altered dendritic length and branching and abnormal retention of dendrites that extend into developing septa. This deficiency was no longer apparent at P7, suggesting partial recovery of dendritic pruning processes. Finally, we showed early defects in synaptogenesis from P4 to P5 with increased colocalization of NR1 and GluR1 staining in HZ mice. By P7, this colocalization had normalized to wild type levels. Taken together, our findings suggest abnormal postsynaptic differentiation in GAP-43 HZ cortex during early barrel development, followed by adaptive compensation and partial phenotypic rescue. PMID:19915093

  14. Excitatory neuronal connectivity in the barrel cortex

    PubMed Central

    Feldmeyer, Dirk

    2012-01-01

    Neocortical areas are believed to be organized into vertical modules, the cortical columns, and the horizontal layers 1–6. In the somatosensory barrel cortex these columns are defined by the readily discernible barrel structure in layer 4. Information processing in the neocortex occurs along vertical and horizontal axes, thereby linking individual barrel-related columns via axons running through the different cortical layers of the barrel cortex. Long-range signaling occurs within the neocortical layers but also through axons projecting through the white matter to other neocortical areas and subcortical brain regions. Because of the ease of identification of barrel-related columns, the rodent barrel cortex has become a prototypical system to study the interactions between different neuronal connections within a sensory cortical area and between this area and other cortical as well subcortical regions. Such interactions will be discussed specifically for the feed-forward and feedback loops between the somatosensory and the somatomotor cortices as well as the different thalamic nuclei. In addition, recent advances concerning the morphological characteristics of excitatory neurons and their impact on the synaptic connectivity patterns and signaling properties of neuronal microcircuits in the whisker-related somatosensory cortex will be reviewed. In this context, their relationship between the structural properties of barrel-related columns and their function as a module in vertical synaptic signaling in the whisker-related cortical areas will be discussed. PMID:22798946

  15. CALIFA Barrel prototype detector characterisation

    NASA Astrophysics Data System (ADS)

    Pietras, B.; Gascón, M.; Álvarez-Pol, H.; Bendel, M.; Bloch, T.; Casarejos, E.; Cortina-Gil, D.; Durán, I.; Fiori, E.; Gernhäuser, R.; González, D.; Kröll, T.; Le Bleis, T.; Montes, N.; Nácher, E.; Robles, M.; Perea, A.; Vilán, J. A.; Winkel, M.

    2013-11-01

    Well established in the field of scintillator detection, Caesium Iodide remains at the forefront of scintillators for use in modern calorimeters. Recent developments in photosensor technology have lead to the production of Large Area Avalanche Photo Diodes (LAAPDs), a huge advancement on traditional photosensors in terms of high internal gain, dynamic range, magnetic field insensitivity, high quantum efficiency and fast recovery time. The R3B physics programme has a number of requirements for its calorimeter, one of the most challenging being the dual functionality as both a calorimeter and a spectrometer. This involves the simultaneous detection of ∼300 MeV protons and gamma rays ranging from 0.1 to 20 MeV. This scintillator - photosensor coupling provides an excellent solution in this capacity, in part due to the near perfect match of the LAAPD quantum efficiency peak to the light output wavelength of CsI(Tl). Modern detector development is guided by use of Monte Carlo simulations to predict detector performance, nonetheless it is essential to benchmark these simulations against real data taken with prototype detector arrays. Here follows an account of the performance of two such prototypes representing different polar regions of the Barrel section of the forthcoming CALIFA calorimeter. Measurements were taken for gamma-ray energies up to 15.1 MeV (Maier-Leibnitz Laboratory, Garching, Germany) and for direct irradiation with a 180 MeV proton beam (The Svedberg Laboratoriet, Uppsala, Sweden). Results are discussed in light of complementary GEANT4 simulations.

  16. Mitochondria can recognize and assemble fragments of a β-barrel structure

    PubMed Central

    Müller, Jonas E.N.; Papic, Drazen; Ulrich, Thomas; Grin, Iwan; Schütz, Monika; Oberhettinger, Philipp; Tommassen, Jan; Linke, Dirk; Dimmer, Kai S.; Autenrieth, Ingo B.; Rapaport, Doron

    2011-01-01

    β-barrel proteins are found in the outer membranes of eukaryotic organelles of endosymbiotic origin as well as in the outer membrane of Gram-negative bacteria. Precursors of mitochondrial β-barrel proteins are synthesized in the cytosol and have to be targeted to the organelle. Currently, the signal that assures their specific targeting to mitochondria is poorly defined. To characterize the structural features needed for specific mitochondrial targeting and to test whether a full β-barrel structure is required, we expressed in yeast cells the β-barrel domain of the trimeric autotransporter Yersinia adhesin A (YadA). Trimeric autotransporters are found only in prokaryotes, where they are anchored to the outer membrane by a single 12-stranded β-barrel structure to which each monomer is contributing four β-strands. Importantly, we found that YadA is solely localized to the mitochondrial outer membrane, where it exists in a native trimeric conformation. These findings demonstrate that, rather than a linear sequence or a complete β-barrel structure, four β-strands are sufficient for the mitochondria to recognize and assemble a β-barrel protein. Remarkably, the evolutionary origin of mitochondria from bacteria enables them to import and assemble even proteins belonging to a class that is absent in eukaryotes. PMID:21460184

  17. NASA Marshall Space Flight Center Barrel-Shaped Asymmetrical Capacitor

    NASA Technical Reports Server (NTRS)

    Campbell, J. W.; Carruth, M. R.; Edwards, D. L.; Finchum, A.; Maxwell, G.; Nabors, S.; Smalley, L.; Huston, D.; Ila, D.; Zimmerman, R.

    2004-01-01

    The NASA Barrel-Shaped Asymmetrical Capacitor (NACAP) has been extensively tested at NASA Marshall Space Flight Center and the National Space Science and Technology Center. Trichel pulse emission was first discovered here. The NACAP is a magnetohydrodynamic device for electric propulsion. In air it requires no onboard propellant nor any moving parts. No performance was observed in hard vacuum. The next step shall be optimizing the technology for future applications.

  18. Cobalt-Base Alloy Gun Barrel Study

    DTIC Science & Technology

    2014-07-01

    Cobalt -Base Alloy Gun Barrel Study by William S. de Rosset and Jonathan S. Montgomery ARL-RP-0491 July 2014 A reprint...21005-5069 ARL-RP-0491 July 2014 Cobalt -Base Alloy Gun Barrel Study William S. de Rosset and Jonathan S. Montgomery Weapons and Materials...DATE (DD-MM-YYYY) July 2014 2. REPORT TYPE Reprint 3. DATES COVERED (From - To) October–November 2013 4. TITLE AND SUBTITLE Cobalt -Base Alloy

  19. Lightweight optical barrel assembly structures for large deployable space telescopes

    NASA Astrophysics Data System (ADS)

    Warren, Peter A.; Silver, Mark J.; Dobson, Benjamin J.

    2009-08-01

    Future space based telescopes will need apertures and focal lengths that exceed the dimensions of the launch vehicle shroud. In addition to deploying the primary mirror and secondary mirror support structure, these large telescopes must also deploy the stray light and thermal barriers needed to ensure proper telescope performance. The authors present a deployable light and thermal optical barrel assembly approach for a very large telescope with a variable sun angle and fast slew rate. The Strain Energy Deployable Optical Barrel Assembly (SEDOBA) uses elastic composite hinges to power the deployment of a hierarchical truss structure that supports the thermal and stray light shroud material that form the overall system. The paper describes the overall design approach, the key component technologies, and the design and preliminary testing of a self deploying scale model prototype.

  20. Effect of Barrel Material on Critical Current Measurements of High-Jc RRP Nb3Sn Wires

    SciTech Connect

    Ghosh, A.

    2011-08-03

    Nb{sub 3}Sn strands extracted from a 20-strand rectangular Rutherford cable were reacted on either stainless steel or Ti-alloy barrels and the critical current, I{sub c}, in the field range of 8-11.5 T was measured on ITER-type barrels made from Ti-6Al-4V alloy, 304 stainless steel and G-10. Measurements on the 'standard' Ti-alloy barrel using the test procedure employed at BNL are shown to reproduce I{sub c} for extracted strands to {+-}2%. The I{sub c} data for the sample mounted on the 'standard' Ti-alloy are fit to the deviatoric strain scaling model developed for Nb{sub 3}Sn by the University of Twente group using an arbitrary pre-strain. Using the parameters for this fit, the I{sub c} data for the other barrels are fitted by only adjusting the strain. Using this procedure, the strain difference due to the barrel material is determined. Assuming a thermal pre-strain of -0.2% for the sample measured on the Ti-alloy barrel, the use of stainless steel barrel increases the compressive strain by -0.07%, that of G-10 by -0.10%. With the wire soldered to the stainless steel barrel, the strain increases to -0.15%. Details of this study are presented.

  1. Rain Barrels: A Catalyst for Change?

    ERIC Educational Resources Information Center

    Bakacs, Michele E.; Haberland, Mike; Mangiafico, Salvatore S.; Winquist, Aileen; Obropta, Christopher C.; Boyajian, Amy; Mellor, Sara

    2013-01-01

    Over the past 4 years, rain barrel programming for residents has been implemented in both Northern Virginia and New Jersey as a method for educating the public about stormwater management and water conservation. Program participants demonstrated a significant increase in knowledge of water resource issues. Follow-up surveys showed 58% of New…

  2. 49 CFR 178.510 - Standards for wooden barrels.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... PACKAGINGS Non-bulk Performance-Oriented Packaging Standards § 178.510 Standards for wooden barrels. (a) The... intended use of the barrel. (3) Staves and heads must be sawn or cleft with the grain so that no...

  3. Silicon photomultiplier characterization for the GlueX barrel calorimeter

    SciTech Connect

    F. Barbosa, J.E. McKisson, J. McKisson, Y. Qiang, E. Smith, C. Zorn

    2012-12-01

    GlueX is a new detector being constructed at Jefferson Laboratory to study gluonic excitations and confinement via the detection of exotic meson states. The hermetic detector includes a barrel calorimeter where the photodetectors must operate in a high magnetic field exceeding 0.5 T. After extensive tests with a variety of sensors, the chosen photodetector will be a custom silicon photomultiplier (SiPM) array manufactured by Hamamatsu Corporation. This paper will focus on the characterization of the first 80 production samples of these SiPMs, including dark rate, photodetection efficiency (PDE), crosstalk, response uniformity and radiation tolerance.

  4. Barrel cortex and whisker-mediated behaviors.

    PubMed

    Brecht, Michael

    2007-08-01

    Neural networks of the rodent barrel cortex are particularly tractable for developing a quantitative understanding of response transformations in a cortical column. A column in barrel cortex consists of approximately 10 compartments. Two thalamic input pathways, a sensory lemniscal one and sensorimotor paralemniscal one, are transformed to approximately 7 population outputs, each with distinct spatiotemporal response characteristics. Granular and supragranular layers are sites of segregated processing in lemniscal and paralemniscal pathways, whereas infragranular layers are sites of intracolumnar, lemniscal/paralemniscal integration. Individual thalamocortical connections are relatively weak, and a considerable fraction of thalamocortical afferents contributes to each sensory response. Intracortically, relatively few but strong synaptic connections contribute to sensory responses, and responses are rapidly terminated by inhibition. Overall cortical population activity is very low. Whiskers mediate a wide range of behaviors and many natural tactile behaviors occur very rapidly. Vibrissal object recognition can be size invariant and motion invariant and is based on the tactile 'Gestaltwahrnehmung' of shape.

  5. Barrel calorimeter of the CMD-3 detector

    SciTech Connect

    Shebalin, V. E. Anisenkov, A. V.; Aulchenko, V. M.; Bashtovoy, N. S.; Epifanov, D. A.; Epshteyn, L. B.; Grebenuk, A. A.; Ignatov, F. V.; Erofeev, A. L.; Kovalenko, O. A.; Kozyrev, A. N.; Kuzmin, A. S.; Logashenko, I. B.; Mikhailov, K. Yu.; Razuvaev, G. P.; Ruban, A. A.; Shwartz, B. A.; Talyshev, A. A.; Titov, V. M.; Yudin, Yu. V.

    2015-12-15

    The structure of the barrel calorimeter of the CMD-3 detector is presented in this work. The procedure of energy calibration of the calorimeter and the method of photon energy restoration are described. The distinctive feature of this barrel calorimeter is its combined structure; it is composed of two coaxial subsystems: a liquid xenon calorimeter and a crystalline CsI calorimeter. The calorimeter spatial resolution of the photon conversion point is about 2 mm, which corresponds to an angular resolution of ∼6 mrad. The energy resolution of the calorimeter is about 8% for photons with energy of 200 MeV and 4% for photons with energy of 1 GeV.

  6. Studies of hadron-electron separators for the ZEUS barrel calorimeter

    SciTech Connect

    Ambats, I.; Bortz, D.; Connolly, A.

    1995-05-25

    Two possible upgrades, a shower maximum detector and a presampler, designed to improve the low energy electron/hadron separation capabilities of the ZEUS barrel calorimeter are described and test-beam results are reported. The presampler can also be used to correct for energy loss of particles traversing the dead material in front of the calorimeter.

  7. Real-time monitoring of barrel thickness and barrel/screw separation using ultrasound

    NASA Astrophysics Data System (ADS)

    Jen, Cheng-Kuei; Zun, Zhigang; Kobayashi, Makiko

    2005-03-01

    Ultrasonic sensors together with a fast data acquisition system have been used to monitor the barrel thickness and barrel/screw separation during low-density polyethylene as well as high-density polyethylene extrusion in 30 mm and 50 mm twin-screw extruders. The sensors include sol-gel sprayed high temperature (HT) piezoelectric thick ceramic film ultrasonic transducers (UTs), stand-alone HTUTs and air-cooled buffer rod type sensors consisting of a room temperature UT and a non-clad or clad buffer rod to which the room temperature UT is attached. The installation and use of these sensors are non-intrusive to the extruder and non-destructive to the polymers being processed. This study has demonstrated the capability of appropriately designed ultrasonic sensors in monitoring the barrel and screw integrity at the melting, mixing and pumping zones of the extruder via barrel or flange. The merits and limitations of these sensors are discussed. The measurement speed and analysis of the sensitivity for quantitative wear measurements are also presented.

  8. 1. EXTERIOR, SIDE OF PICKLE BARREL RESTAURANT AND ADJOINING STORE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. EXTERIOR, SIDE OF PICKLE BARREL RESTAURANT AND ADJOINING STORE - Silverton Historic District, East Thirteenth & Green Streets (Commercial Building), East Thirteenh & Green Streets, Silverton, San Juan County, CO

  9. Parametric modeling of zoom lens barrels

    NASA Astrophysics Data System (ADS)

    Pierce, Charles W.

    2001-12-01

    Today's customer requires zoom lens designs that are compact, inexpensive, and at six-sigma quality levels. While incorporating these customer requirements, a design team must often work within compressed design cycles and minimal product development budgets. These customer and project constraints, coupled with the inherent complexity of a zoom lens module, force the design team to try new and innovative techniques to deliver their products. This paper presents the methods used to develop lens barrels for several zoom lens module projects at Eastman Kodak Company. The lens barrel, a critical interface between the mechanical and optical systems, presented a technical barrier from both an engineering analysis and manufacturing perspective. The method used to overcome these barriers consisted of identifying several key functional parameters, creating a parameter-driven 3-D solid model in a commercially available CAD system, and then using the model to make iterative, data-driven design decisions while leveraging the model to create engineering drawings and the necessary prototypes and production tooling. As a result, the designs were able to meet their size, cost, and design cycle time requirements while realizing a better than anticipated first pass yield and quality level.

  10. Observations of a solar storm from the stratosphere: The BARREL Mission

    NASA Astrophysics Data System (ADS)

    Halford, Alexa

    2016-07-01

    During the Balloon Array for Radiation belt Relativistic Electron Losses (BARREL) second campaign, BARREL observed with a single primary instrument, a 3"x3" NaI spectrometer measuring 20 keV - 10 MeV X-rays [Woodger et al 2015 JGR], portions of an entire solar storm. This very small event, in terms of geomagnetic activity, or one of the largest of the current solar cycle, in terms of solar energetic particle events, has given us a very clear set of observations of the response of the day side magnetosphere to the arrival of an interplanetary coronal mass ejection shock. The BARREL mission of opportunity working in tandem with the Van Allen Probes was designed to study the loss of radiation belt electrons to the ionosphere and upper atmosphere. However BARREL is able to see X-rays from a multitude of sources. During the second campaign, the Sun produced, and BARREL observed, an X-class flare [McGregor et al in prep.]. This was followed by BARREL observations of X-rays, gamma-rays, and directly injected protons from the solar energetic particle (SEP) event associated with the eruption from the Sun while simultaneously the Van Allen Probes observed the SEP protons in the inner magnetosphere [Halford et al 2016 submitted JGR]. Two days later the shock generated by the interplanetary coronal mass ejection (ICME-shock) hit the Earth while BARREL was in conjunction with the Van Allen Probes and GOES [Halford et al 2015 JGR]. Although this was a Mars directed CME and the Earth only received a glancing blow [Möstl et al 2015 Nat. Commun., Mays et al 2015 ApJ], the modest compression led to the formation of ultra low frequency (ULF) waves, electromagnetic ion cyclotron (EMIC) waves, and very low frequency (VLF) whistler mode waves [Halford and Mann 2016 submitted to JGR]. The combination of these waves and the enhancement of the local particle population led to precipitation of electrons remotely observed by BARREL. This was not a Halloween, Bastille Day, or one of the now

  11. An outbreak of norovirus-associated acute gastroenteritis associated with contaminated barrelled water in many schools in Zhejiang, China

    PubMed Central

    Sheng, Minyang; Song, Jianqiang; He, Fan; Qiu, Yinwei; Wu, Haocheng; Lu, Qinbao; Feng, Yan; Lin, Junfen; Chen, Enfu; Chai, Chengliang

    2017-01-01

    Objectives More than 900 students and teachers at many schools in Jiaxing city developed acute gastroenteritis in February 2014. An immediate epidemiological investigation was conducted to identify the pathogen, infection sources and route of transmission. Methods The probable cases and confirmed cases were defined as students or teachers with diarrhoea or vomiting present since the term began in February 2014. An active search was conducted for undiagnosed cases among students and teachers. Details such as demographic characteristics, gastrointestinal symptoms, and drinking water preference and frequency were collected via a uniform epidemiological questionnaire. A case-control study was implemented, and odds ratios (ORs) and 95% confidence intervals were calculated. Rectal swabs from several patients, food handlers and barrelled water factory workers, as well as water and food samples, were collected to test for potential bacteria and viruses. Results A total of 924 cases fit the definition of the probable case, including 8 cases of laboratory-confirmed norovirus infection at 13 schools in Jiaxing city between February 12 and February 21, 2014. The case-control study demonstrated that barrelled water was a risk factor (OR: 20.15, 95% CI: 2.59–156.76) and that bottled water and boiled barrelled water were protective factors (OR: 0.31, 95% CI: 0.13–0.70, and OR: 0.36, 95% CI: 0.16–0.77). A total of 11 rectal samples and 8 barrelled water samples were detected as norovirus-positive, and the genotypes of viral strains were the same (GII). The norovirus that contaminated the barrelled water largely came from the asymptomatic workers. Conclusions This acute gastroenteritis outbreak was caused by barrelled water contaminated by norovirus. The outbreak was controlled after stopping the supply of barrelled water. The barrelled water supply in China represents a potential source of acute gastroenteritis outbreaks due to the lack of surveillance and supervision

  12. The CMS Level-1 Trigger Barrel Track Finder

    NASA Astrophysics Data System (ADS)

    Ero, J.; Evangelou, I.; Flouris, G.; Foudas, C.; Guiducci, L.; Loukas, N.; Manthos, N.; Papadopoulos, I.; Paradas, E.; Sotiropoulos, S.; Sphicas, P.; Triossi, A.; Wulz, C.

    2016-03-01

    The design and performance of the upgraded CMS Level-1 Trigger Barrel Muon Track Finder (BMTF) is presented. Monte Carlo simulation data as well as cosmic ray data from a CMS muon detector slice test have been used to study in detail the performance of the new track finder. The design architecture is based on twelve MP7 cards each of which uses a Xilinx Virtex-7 FPGA and can receive and transmit data at 10 Gbps from 72 input and 72 output fibers. According to the CMS Trigger Upgrade TDR the BMTF receives trigger primitive data which are computed using both RPC and DT data and transmits data from a number of muon candidates to the upgraded Global Muon Trigger. Results from detailed studies of comparisons between the BMTF algorithm results and the results of a C++ emulator are also presented. The new BMTF will be commissioned for data taking in 2016.

  13. OMPcontact: An Outer Membrane Protein Inter-Barrel Residue Contact Prediction Method.

    PubMed

    Zhang, Li; Wang, Han; Yan, Lun; Su, Lingtao; Xu, Dong

    2017-03-01

    In the two transmembrane protein types, outer membrane proteins (OMPs) perform diverse important biochemical functions, including substrate transport and passive nutrient uptake and intake. Hence their 3D structures are expected to reveal these functions. Because experimental structures are scarce, predicted 3D structures are more adapted to OMP research instead, and the inter-barrel residue contact is becoming one of the most remarkable features, improving prediction accuracy by describing the structural information of OMPs. To predict OMP structures accurately, we explored an OMP inter-barrel residue contact prediction method: OMPcontact. Multiple OMP-specific features were integrated in the method, including residue evolutionary covariation, topology-based transmembrane segment relative residue position, OMP lipid layer accessibility, and residue evolution conservation. These features describe the properties of a residue pair in different respects: sequential, structural, evolutionary, and biochemical. Within a 3-residues slide window, a Support Vector Machine (SVM) could accurately determinate the inter-barrel contact residue pair using above features. A 5-fold cross-valuation process was applied in testing the OMPcontact performance against a non-redundant OMP set with 75 samples inside. The tests compared four evolutionary covariation methods and screen analyzed the adaptive ones for inter-barrel contact prediction. The results showed our method not only efficiently realized the prediction, but also scored the possibility for residue pairs reliably. This is expected to improve OMP tertiary structure prediction. Therefore, OMPcontact will be helpful in compiling a structural census of outer membrane protein.

  14. 27 CFR 25.141 - Barrels and kegs.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Barrels and kegs. 25.141 Section 25.141 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS BEER Marks, Brands, and Labels § 25.141 Barrels and kegs. (a)...

  15. Twenty years of barrel-stave flextensional transducer technology in Canada

    NASA Astrophysics Data System (ADS)

    Jones, Dennis F.

    2005-04-01

    The barrel-stave flextensional transducer, a compact underwater sound source, was conceived at DRDC Atlantic in 1986 [G. W. McMahon and D. F. Jones, U.S. Patent No. 4,922,470 (1 May 1990); Canadian Patent No. 1,285,646 (2 July 1991)]. Over the years, five barrel-stave designs belonging to three flextensional classes were built and tested at DRDC Atlantic. Three Class I transducers with operating frequencies ranging from 800 to 1600 Hz were integrated into submarine communications buoys, low frequency active horizontal projector arrays, and a broadband sonar towbody. A high-power Class II and broadband (1-7 kHz) Class III transducer were deployed under the ice in the Lincoln Sea for research related to rapidly deployable surveillance systems. These barrel-stave flextensional transducers have also supported a variety of marine mammal studies including vocal mimicry in long-finned pilot whales, coda dialects in sperm whales, and the R&D of acoustic detection and tracking systems for endangered northern right whales. In August 2004 a barrel-stave transducer was used to lure a trapped juvenile humpback whale to the sluice gates of a tidal generating station on the Annapolis River in Nova Scotia by transmitting humpback whale calls underwater. The acoustic performance parameters for all 5 transducers will be presented.

  16. Superior long-term stability of a glucose biosensor based on inserted barrel plating gold electrodes.

    PubMed

    Hsu, Cheng-Teng; Hsiao, Hung-Chan; Fang, Mei-Yen; Zen, Jyh-Myng

    2009-10-15

    Disposable one shot usage blood glucose strips are routinely used in the diagnosis and management of diabetes mellitus and their performance can vary greatly. In this paper we critically evaluated the long-term stability of glucose strips made of barrel plating gold electrodes. Compared to other glucose biosensing platforms of vapor deposited palladium and screen printed carbon electrodes, the proposed glucose biosensor was found to show the best stability among the three biosensing platforms in thermal acceleration experiments at 40 degrees C for 6 months with an average bias of 3.4% at glucose concentrations of 5-20 mM. The precision test of this barrel plating gold glucose biosensor also showed the best performance (coefficients of variation in the range of 1.4-2.4%) in thermal acceleration experiments at 40 degrees C, 50 degrees C and 70 degrees C for 27 days. Error grid analysis revealed that all measurements fell in zone A and zone B. Regression analysis showed no significant difference between the proposed biosensor and the reference method at 99% confidence level. The amperometric glucose biosensor fabricated by inserting two barrel plating gold electrodes onto an injection-molding plastic base followed by immobilizing with a bio-reagent layer and membrane was very impressive with a long-term stability up to 2.5 years at 25 degrees C. Overall, these results indicated that the glucose oxidase/barrel plating gold biosensing platform is ideal for long-term accurate glycemic control.

  17. Effects of Dimethyl Sulfoxide on Neuronal Response Characteristics in Deep Layers of Rat Barrel Cortex

    PubMed Central

    Soltani, Narjes; Mohammadi, Elham; Allahtavakoli, Mohammad; Shamsizadeh, Ali; Roohbakhsh, Ali; Haghparast, Abbas

    2016-01-01

    Introduction: Dimethyl sulfoxide (DMSO) is a chemical often used as a solvent for water-insoluble drugs. In this study, we evaluated the effect of intracerebroventricular (ICV) administration of DMSO on neural response characteristics (in 1200–1500 μm depth) of the rat barrel cortex. Methods: DMSO solution was prepared in 10% v/v concentration and injected into the lateral ventricle of rats. Neuronal spontaneous activity and neuronal responses to deflection of the principal whisker (PW) and adjacent whisker (AW) were recorded in barrel cortex. A condition test ratio (CTR) was used to measure inhibitory receptive fields in barrel cortex. Results: The results showed that both PW and AW evoked ON and OFF responses, neuronal spontaneous activity and inhibitory receptive fields did not change following ICV administration of DMSO. Conclusion: Results of this study suggest that acute ICV administration of 10% DMSO did not modulate the electrophysiological characteristics of neurons in the l deep ayers of rat barrel cortex. PMID:27563414

  18. All-atom 3D structure prediction of transmembrane β-barrel proteins from sequences

    PubMed Central

    Hayat, Sikander; Sander, Chris; Marks, Debora S.

    2015-01-01

    Transmembrane β-barrels (TMBs) carry out major functions in substrate transport and protein biogenesis but experimental determination of their 3D structure is challenging. Encouraged by successful de novo 3D structure prediction of globular and α-helical membrane proteins from sequence alignments alone, we developed an approach to predict the 3D structure of TMBs. The approach combines the maximum-entropy evolutionary coupling method for predicting residue contacts (EVfold) with a machine-learning approach (boctopus2) for predicting β-strands in the barrel. In a blinded test for 19 TMB proteins of known structure that have a sufficient number of diverse homologous sequences available, this combined method (EVfold_bb) predicts hydrogen-bonded residue pairs between adjacent β-strands at an accuracy of ∼70%. This accuracy is sufficient for the generation of all-atom 3D models. In the transmembrane barrel region, the average 3D structure accuracy [template-modeling (TM) score] of top-ranked models is 0.54 (ranging from 0.36 to 0.85), with a higher (44%) number of residue pairs in correct strand–strand registration than in earlier methods (18%). Although the nonbarrel regions are predicted less accurately overall, the evolutionary couplings identify some highly constrained loop residues and, for FecA protein, the barrel including the structure of a plug domain can be accurately modeled (TM score = 0.68). Lower prediction accuracy tends to be associated with insufficient sequence information and we therefore expect increasing numbers of β-barrel families to become accessible to accurate 3D structure prediction as the number of available sequences increases. PMID:25858953

  19. All-atom 3D structure prediction of transmembrane β-barrel proteins from sequences.

    PubMed

    Hayat, Sikander; Sander, Chris; Marks, Debora S; Elofsson, Arne

    2015-04-28

    Transmembrane β-barrels (TMBs) carry out major functions in substrate transport and protein biogenesis but experimental determination of their 3D structure is challenging. Encouraged by successful de novo 3D structure prediction of globular and α-helical membrane proteins from sequence alignments alone, we developed an approach to predict the 3D structure of TMBs. The approach combines the maximum-entropy evolutionary coupling method for predicting residue contacts (EVfold) with a machine-learning approach (boctopus2) for predicting β-strands in the barrel. In a blinded test for 19 TMB proteins of known structure that have a sufficient number of diverse homologous sequences available, this combined method (EVfold_bb) predicts hydrogen-bonded residue pairs between adjacent β-strands at an accuracy of ∼70%. This accuracy is sufficient for the generation of all-atom 3D models. In the transmembrane barrel region, the average 3D structure accuracy [template-modeling (TM) score] of top-ranked models is 0.54 (ranging from 0.36 to 0.85), with a higher (44%) number of residue pairs in correct strand-strand registration than in earlier methods (18%). Although the nonbarrel regions are predicted less accurately overall, the evolutionary couplings identify some highly constrained loop residues and, for FecA protein, the barrel including the structure of a plug domain can be accurately modeled (TM score = 0.68). Lower prediction accuracy tends to be associated with insufficient sequence information and we therefore expect increasing numbers of β-barrel families to become accessible to accurate 3D structure prediction as the number of available sequences increases.

  20. Software development for the P¯ANDA barrel DIRC

    NASA Astrophysics Data System (ADS)

    Dutta, Dipanwita; P¯ANDA Cherenkov Group

    2011-05-01

    The charged particle identification in the barrel region of the P¯ANDA detector in the future FAIR facility at GSI is planned with a very thin Cherenkov detector using the DIRC principle. Due to a very compact design of the barrel DIRC with focusing optics, the reconstruction of the Cherenkov angle is quite challenging. In this contribution, the possible reconstruction algorithm of the barrel DIRC will be discussed, with emphasis on the possibility to include the DIRC in the trigger decision and the correction of the chromatic dispersion with fast timing information.

  1. 8. VIEW NORTHWEST OF EAST ELEVATION SOUTH BARREL ARCH. NOTE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. VIEW NORTHWEST OF EAST ELEVATION SOUTH BARREL ARCH. NOTE STONE WORK, 1920 CONCRETE REPAIRS, AND STEEL BRACES ADDED BY THE NATIONAL PARK SERVICE CIRCA 1962. - Chesapeake & Ohio Canal, Conococheague Creek Aqueduct, Milepost 99.80, Williamsport, Washington County, MD

  2. Staining in firearm barrels after experimental contact shots.

    PubMed

    Schyma, C; Bauer, K; Brünig, J; Courts, C; Madea, B

    2017-04-01

    After contact shots to the head biological traces inside firearm barrels can be found. This study was conducted to simulate and to evaluate such staining. Five current handguns of four inch barrel length in the calibre .22 long rifle, 7.65mm Browning, 9mm Luger and .38 special were used to perform 24 contact shots on silicone coated, gelatine filled box models using the triple contrast method. The staining was documented by endoscopy and swabs gathered from both ends of the barrel were analysed by quantitative PCR. With the exception of the .22 revolver, all firearms showed distinct staining which decreased from the muzzle to the rear end of the barrel. The pattern was varied, showing droplets, elongated forms or stripes. In 14 of 24 shots, staining reached the chamber. The staining results were comparable to real suicide cases.

  3. Allen Auditorium attic looking from southeast corner. Wine barrels with ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Allen Auditorium attic looking from southeast corner. Wine barrels with scrap used for counterweight material for lift up walls no longer in use - Sheldon Jackson College, Richard H. Allen Memorial Hall, Lincoln Street, Sitka, Sitka Borough, AK

  4. 18. CONSTRUCTION PROGRESS PHOTO SHOWING SURPLUS GUN BARRELS IN PLACE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    18. CONSTRUCTION PROGRESS PHOTO SHOWING SURPLUS GUN BARRELS IN PLACE TO BE USED AS PIPE TUNNELS. INEEL PHOTO NUMBER NRTS-59-925. - Idaho National Engineering Laboratory, Old Waste Calcining Facility, Scoville, Butte County, ID

  5. 16. CONSTRUCTION PROGRESS PHOTO SHOWING SURPLUS GUN BARREL BEING LOWERED ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    16. CONSTRUCTION PROGRESS PHOTO SHOWING SURPLUS GUN BARREL BEING LOWERED INTO PLACE FOR USE AS PIPE TUNNEL. INEEL PHOTO NUMBER NRTS-59-709. - Idaho National Engineering Laboratory, Old Waste Calcining Facility, Scoville, Butte County, ID

  6. Finite element analysis of the SDC barrel and endcap calorimeters

    SciTech Connect

    Guarino, V.; Hill, N.; Nasiakta, J.

    1992-03-11

    In designing the SCD barrel and endcap calorimeters, the inter-module connecting forces must be known in order to determine the required size and number of connecting links between modules, and in order to understand how individual modules will be affected by these forces when assembled to form a full barrel and endcap. The connecting forces were found by analyzing three-dimensional Finite Element Models of both the barrel and endcap. This paper is divided into two parts, the first part will describe in detail the results of the barrel analysis and the second part will describe the results obtained from the endcap analysis. A similar approach was used in constructing the models for both analysis.

  7. 49 CFR 178.510 - Standards for wooden barrels.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) SPECIFICATIONS FOR PACKAGINGS Non... of the barrel. (3) Staves and heads must be sawn or cleft with the grain so that no annual...

  8. 3. BARREL VIEW, LOOKING DOWN LENGTH OF BRIDGE, SHOWING MAKER'S ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. BARREL VIEW, LOOKING DOWN LENGTH OF BRIDGE, SHOWING MAKER'S PLATE, DECORATIVE SCROLLWORK AND URN FINIALS ON NORTHEAST PORTAL - "Forder" Pratt Through Truss Bridge, Spanning Maumee River at County Route 73, Antwerp, Paulding County, OH

  9. INTERIOR VIEW, DETAIL OF BARREL ROOF STRUCTURE, FACING NORTHEAST. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    INTERIOR VIEW, DETAIL OF BARREL ROOF STRUCTURE, FACING NORTHEAST. - Southern Branch of the National Home for Disabled Volunteer Soldiers, Building 13, Harris Avenue at its intersection of Black Avenue and Woodfin Street, Hampton, Hampton, VA

  10. Performance of Prototypes for the Barrel Part of the ANDA Electromagnetic Calorimeter

    NASA Astrophysics Data System (ADS)

    Rosenbaum, Christoph; Diehl, S.; Dormenev, V.; Drexler, P.; Kavatsyuk, M.; Kuske, T.; Nazarenko, S.; Novotny, R.; Rosier, P.; Ryazantsev, A.; Wieczorek, P.; Wilms, A.; Zaunick, H.-G.; P¯ANDA Collaboration

    2016-08-01

    The performance of the most recent prototypes of the ANDA barrel electromagnetic calorimeter (EMC) will be compared. The first large scale prototype PROTO60 was designed to test the performance of the improved tapered lead tungstate crystals (PWO-II). The PROTO60 which consists of 6 × 10 crystals was tested at various accelerator facilities over the complete envisaged energy range fulfilling the requirements of the TDR of the ANDA EMC in terms of energy, position and time resolution. To realize the final barrel geometry and to test the final front end electronics, a second prototype PROTO120 has been constructed. It represents a larger section of a barrel slice, containing the most tapered crystals and the close to final components for the ANDA EMC. The performance of both prototypes will be compared with a focus on the analysis procedure including the signal extraction, noise rejection, calibration and the energy resolution. In addition, the influence of the non-uniformity of the crystal on the energy resolution will be discussed.

  11. Plasticity-Related Gene 1 Affects Mouse Barrel Cortex Function via Strengthening of Glutamatergic Thalamocortical Transmission.

    PubMed

    Unichenko, Petr; Kirischuk, Sergei; Yang, Jenq-Wei; Baumgart, Jan; Roskoden, Thomas; Schneider, Patrick; Sommer, Angela; Horta, Guilherme; Radyushkin, Konstantin; Nitsch, Robert; Vogt, Johannes; Luhmann, Heiko J

    2016-07-01

    Plasticity-related gene-1 (PRG-1) is a brain-specific protein that modulates glutamatergic synaptic transmission. Here we investigated the functional role of PRG-1 in adolescent and adult mouse barrel cortex both in vitro and in vivo. Compared with wild-type (WT) animals, PRG-1-deficient (KO) mice showed specific behavioral deficits in tests assessing sensorimotor integration and whisker-based sensory discrimination as shown in the beam balance/walking test and sandpaper tactile discrimination test, respectively. At P25-31, spontaneous network activity in the barrel cortex in vivo was higher in KO mice compared with WT littermates, but not at P16-19. At P16-19, sensory evoked cortical responses in vivo elicited by single whisker stimulation were comparable in KO and WT mice. In contrast, at P25-31 evoked responses were smaller in amplitude and longer in duration in WT animals, whereas KO mice revealed no such developmental changes. In thalamocortical slices from KO mice, spontaneous activity was increased already at P16-19, and glutamatergic thalamocortical inputs to Layer 4 spiny stellate neurons were potentiated. We conclude that genetic ablation of PRG-1 modulates already at P16-19 spontaneous and evoked excitability of the barrel cortex, including enhancement of thalamocortical glutamatergic inputs to Layer 4, which distorts sensory processing in adulthood.

  12. Composting barrel for sustainable organic waste management in Bangladesh.

    PubMed

    Moqsud, Md Azizul; Bushra, Quazi Sifat; Rahman, M H

    2011-12-01

    To ensure quick and uniform aerobic stabilization of biowaste through domestic composting and to prevent malodorous emissions, two modifications were made to a conventional steel barrel composter by: (1) providing 0.0125 m diameter openings throughout the sides and (2) placing a 0.0254 m diameter perforated polyvinyl chloride (PVC) pipe in the middle portion of the barrel. The volume of composting waste before modification of the composting barrel was 40% of the original volume and it was 70%, 4 weeks following the modifications. In addition, the nutrients in the compost were found to be in a more suitable range after modification of the composting barrel. The carbon-nitrogen ratio (C/N) of the compost was in the ideal range of 11-15 in the modified composting reactor but it was quite high (24-25) in the conventional barrel. This modified barrel composting plant proved to be an efficient, eco-friendly, cost-effective solution for the management of organic solid waste materials in developing and technologically less sophisticated countries such as Bangladesh.

  13. Emissions of polynuclear aromatic hydrocarbons from the open burning of household waste in barrels. Report for July--December 1997

    SciTech Connect

    Lutes, C.C.; Lemieux, P.M.; Abbott, J.A.; Aldous, K.M.

    1997-12-31

    The paper discusses emissions of polynuclear aromatic hydrocarbons (PAHs) from the open burning of household waste in barrels. Using a waste mixture designed to simulate waste generated by an avid cycler and a non-cycler, the emissions of volatile and semivolatile organic compounds, metals, acid gases, and respirable particulates were measured from a 55-gal. (208-L) burn barrel at EPA`s open burning test facility. Total measured PAH emissions ranged from 24 (avid recycler) to 82 mg/kg (non-recycler) of a waste burned. This study provides important data on a potentially significant source of emissions of air toxics.

  14. Lens barrel design of the NIRST IR Camera

    NASA Astrophysics Data System (ADS)

    Côté, Patrice; Leclerc, Mélanie; Châteauneuf, François; Marraco, Hugo

    2009-08-01

    The use of uncooled microbolometer detectors for space infrared (IR) imaging application requires high optical throughput, which leads to very fast optical design (~f/1). This directly translates into stringent requirements for components, assembly and alignment. The Institut National d'Optique (INO) in Quebec City, Canada, designed such a system for the NIRST IR Camera. The instrument is part of the Aquarius/SAC-D satellite, a cooperative mission conducted jointly by NASA and the Comisión Nacional de Actividades Espaciales (CONAE) of Argentina. Due to the tight volume and mass allocation, the NIRST camera module is an all refractive design. Since the Camera is made of two lens barrels co-registered to cover the same ground area at different wavelength bands, it also adds coregistration alignment constraints. This paper presents the optomechanical solutions and alignment scheme that enabled the successful design and flight qualification. Trade-off study between thermally induced stress and structural stiffness of the lens RTV bond is discussed. Special attention is given to lens subcell alignment integrity under random vibration encountered during launch. Detailed Finite Element Analysis (FEA) is used to check early design assumptions. Test results of the final vibration campaign are also presented.

  15. Compressibility and Heating Effects on Pressure Loss and Cooling of a Baffled Cylinder Barrel

    NASA Technical Reports Server (NTRS)

    Goldstein, Arthur W.; Ellerbrock, Herman H., Jr.

    1944-01-01

    Theoretical investigations have shown that, because air is compressible, the pressure-drop requirements for cooling an air-cooled engine will be much greater at high altitudes and high speeds than at sea level and low speeds. Tests were conducted by the NACA to obtain some experimental confirmation of the effect of air compressibility on cooling and pressure loss of a baffled cylinder barrel and to evaluate various methods of analysis. The results reported in the present paper are regarded as preliminary to tests on single-cylinder and multi-cylinder engines. Tests were conducted over a wide range of air flows and density altitudes.

  16. Compressibility and Heating Effects on Pressure Loss and Cooling of a Baffled Cylinder Barrel

    NASA Technical Reports Server (NTRS)

    Goldstein, Arthur W; Ellerbrock, Herman H , Jr

    1944-01-01

    Theoretical investigations have shown that, because air is compressible, the pressure-drop requirements for cooling an air-cooled engine will be much greater at high altitudes and high speeds than at sea level and low speeds. Tests were conducted by the NACA to obtain some experimental confirmation of the effect of air compressibility on cooling and pressure loss of a baffled cylinder barrel and to evaluate various methods of analysis. The results reported in the present paper are regarded as preliminary to tests on single-cylinder and multicylinder engines. Tests were conducted over a wide range of air flows and density altitudes.

  17. Aroma potential of oak battens prepared from decommissioned oak barrels.

    PubMed

    Li, Sijing; Crump, Anna M; Grbin, Paul R; Cozzolino, Daniel; Warren, Peter; Hayasaka, Yoji; Wilkinson, Kerry L

    2015-04-08

    During barrel maturation, volatile compounds are extracted from oak wood and impart aroma and flavor to wine, enhancing its character and complexity. However, barrels contain a finite pool of extractable material, which diminishes with time. As a consequence, most barrels are decommissioned after 5 or 6 years. This study investigated whether or not decommissioned barrels can be "reclaimed" and utilized as a previously untapped source of quality oak for wine maturation. Oak battens were prepared from staves of decommissioned French and American oak barrels, and their composition analyzed before and after toasting. The oak lactone glycoconjugate content of untoasted reclaimed oak was determined by liquid chromatography-tandem mass spectrometry, while the concentrations of cis- and trans-oak lactone, guaiacol, 4-methlyguaiacol, vanillin, eugenol, furfural, and 5-methylfurfural present in toasted reclaimed oak were determined by gas chromatography-mass spectrometry. Aroma potential was then evaluated by comparing the composition of reclaimed oak with that of new oak. Comparable levels of oak lactone glycoconjugates and oak volatiles were observed, demonstrating the aroma potential of reclaimed oak and therefore its suitability as a raw material for alternative oak products, i.e., chips or battens, for the maturation of wine. The temperature profiles achieved during toasting were also measured to evaluate the viability of any yeast or bacteria present in reclaimed oak.

  18. β-Barrel membrane protein assembly by the Bam complex.

    PubMed

    Hagan, Christine L; Silhavy, Thomas J; Kahne, Daniel

    2011-01-01

    β-barrel membrane proteins perform important functions in the outer membranes (OMs) of Gram-negative bacteria and of the mitochondria and chloroplasts of eukaryotes. The protein complexes that assemble these proteins in their respective membranes have been identified and shown to contain a component that has been conserved from bacteria to humans. β-barrel proteins are handled differently from α-helical membrane proteins in the cell in order to efficiently transport them to their final locations in unfolded but folding-competent states. The mechanism by which the assembly complex then binds, folds, and inserts β-barrels into the membrane is not well understood, but recent structural, biochemical, and genetic studies have begun to elucidate elements of how the complex provides a facilitated pathway for β-barrel assembly. Ultimately, studies of the mechanism of β-barrel assembly and comparison to the better-understood process of α-helical membrane protein assembly will reveal whether there are general principles that guide the folding and insertion of all membrane proteins.

  19. Amyloid β-Protein C-Terminal Fragments: Formation of Cylindrins and β-Barrels.

    PubMed

    Do, Thanh D; LaPointe, Nichole E; Nelson, Rebecca; Krotee, Pascal; Hayden, Eric Y; Ulrich, Brittany; Quan, Sarah; Feinstein, Stuart C; Teplow, David B; Eisenberg, David; Shea, Joan-Emma; Bowers, Michael T

    2016-01-20

    In order to evaluate potential therapeutic targets for treatment of amyloidoses such as Alzheimer's disease (AD), it is essential to determine the structures of toxic amyloid oligomers. However, for the amyloid β-protein peptide (Aβ), thought to be the seminal neuropathogenetic agent in AD, its fast aggregation kinetics and the rapid equilibrium dynamics among oligomers of different size pose significant experimental challenges. Here we use ion-mobility mass spectrometry, in combination with electron microscopy, atomic force microscopy, and computational modeling, to test the hypothesis that Aβ peptides can form oligomeric structures resembling cylindrins and β-barrels. These structures are hypothesized to cause neuronal injury and death through perturbation of plasma membrane integrity. We show that hexamers of C-terminal Aβ fragments, including Aβ(24-34), Aβ(25-35) and Aβ(26-36), have collision cross sections similar to those of cylindrins. We also show that linking two identical fragments head-to-tail using diglycine increases the proportion of cylindrin-sized oligomers. In addition, we find that larger oligomers of these fragments may adopt β-barrel structures and that β-barrels can be formed by folding an out-of-register β-sheet, a common type of structure found in amyloid proteins.

  20. Amyloid β-Protein C-terminal Fragments: Formation of Cylindrins and β-barrels

    PubMed Central

    Do, Thanh D.; LaPointe, Nichole E.; Nelson, Rebecca; Krotee, Pascal; Hayden, Eric Y.; Ulrich, Brittany; Quan, Sarah; Feinstein, Stuart C.; Teplow, David B.; Eisenberg, David; Shea, Joan-Emma; Bowers, Michael T.

    2016-01-01

    In order to evaluate potential therapeutic targets for treatment of amyloidoses such as Alzheimer’s disease (AD), it is essential to determine the structures of toxic amyloid oligomers. However, for the amyloid β-protein peptide (Aβ), thought to be the seminal neuropathogenetic agent in AD, its fast aggregation kinetics and the rapid equilibrium dynamics among oligomers of different size pose significant experimental challenges. Here we use ion-mobility mass spectrometry, in combination with electron microscopy, atomic force microscopy, and computational modeling, to test the hypothesis that Aβ peptides can form oligomeric structures resembling cylindrins and β-barrels. These structures are hypothesized to cause neuronal injury and death through perturbation of plasma membrane integrity. We show that hexamers of C-terminal Aβ fragments, including Aβ(24-34), Aβ(25-35) and Aβ(26-36), have collision cross-sections similar to those of cylindrins. We also show that linking two identical fragments head-to-tail using di-glycine increases the proportion of cylindrin-sized oligomers. In addition, we find that larger oligomers of these fragments may adopt β-barrel structures and that β-barrels can be formed by folding an out-of-register β-sheet, a common type of structure found in amyloid proteins. PMID:26700445

  1. Early bilateral sensory deprivation blocks the development of coincident discharge in rat barrel cortex.

    PubMed

    Ghoshal, Ayan; Pouget, Pierre; Popescu, Maria; Ebner, Ford

    2009-02-25

    Several theories have proposed a functional role for synchronous neuronal firing in generating the neural code of a sensory perception. Synchronous neural activity develops during a critical postnatal period of cortical maturation, and severely reducing neural activity in a sensory pathway during this period could interfere with the development of coincident discharge among cortical neurons. Loss of such synchrony could provide a fundamental mechanism for the degradation of acuity shown in behavioral studies. We tested the hypothesis that synchronous discharge of barrel cortex neurons would fail to develop after sensory deprivation produced by bilateral whisker trimming from birth to postnatal day 60. By studying the correlated discharge of cortical neuron pairs, we found evidence for strong correlated firing in control animals, and this synchrony was almost absent among pairs of cortical barrel neurons in deprived animals. The degree of synchrony impairment was different in subregions of rat barrel cortex. The model that best fits the data is that cortical neurons receiving direct inputs from the primary sensory (lemniscal) pathway show the greatest decrement in synchrony following sensory deprivation, while neurons with diverse inputs from other areas of thalamus and cortex are relatively less affected in this dimension of cortical function.

  2. Mapping plasticity in the forepaw digit barrel subfield of rat brains using functional MRI

    PubMed Central

    Weng, Jun-Cheng; Chuang, Kai-Hsiang; Goloshevsky, Artem; Dodd, Stephen J.; Sharer, Kathryn

    2012-01-01

    The topographic organization of the forepaw barrel subfield in layer IV of rat primary somatosensory cortex (S1) is a good model for studying neural function and plasticity. The goal of this study was to test the feasibility of functional MRI (fMRI) to map the forepaw digit representations in the S1 of the rat and its plasticity after digit amputation. Three dimentional echo-planar imaging with 300 micron isotropic resolution at 11.7 T was used to achieve high signal-to-noise ratios and laminar layer resolution. By alternating electrical stimulation of the 2nd (D2) and 4th (D4) digits, functional activation in layer IV of the barrel subfields could be distinguished using a differential analysis. Furthermore, two and a half months after the amputation of the 3rd digit in baby rats, the overlapping area between D2 and D4 representations was increased. This indicates that the forepaw barrel subfield previously associated with the ablated digit is now associated with the representation of nearby digits, which is consistent with studies using electrophysiology and cytochrome oxidase staining. PMID:20804851

  3. Small arms mini-fire control system: fiber-optic barrel deflection sensor

    SciTech Connect

    Rajic, Slobodan; Datskos, Panos G

    2012-01-01

    Traditionally the methods to increase firearms accuracy, particularly at distance, have concentrated on barrel isolation (free floating) and substantial barrel wall thickening to gain rigidity. This barrel stiffening technique did not completely eliminate barrel movement but the problem was significantly reduced to allow a noticeable accuracy enhancement. This process, although highly successful, came at a very high weight penalty. Obviously the goal would be to lighten the barrel (firearm), yet achieve even greater accuracy. Thus, if lightweight barrels could ultimately be compensated for both their static and dynamic mechanical perturbations, the result would be very accurate, yet significantly lighter weight, weapons. We discuss our development of a barrel reference sensor system that is designed to accomplish this ambitious goal. Our optical fiber-based sensor monitors the barrel muzzle position and autonomously compensates for any induced perturbations. The reticle is electronically adjusted in position to compensate for the induced barrel deviation in real time.

  4. Small arms mini-fire control system: fiber-optic barrel deflection sensor

    NASA Astrophysics Data System (ADS)

    Rajic, S.; Datskos, P.; Lawrence, W.; Marlar, T.; Quinton, B.

    2012-06-01

    Traditionally the methods to increase firearms accuracy, particularly at distance, have concentrated on barrel isolation (free floating) and substantial barrel wall thickening to gain rigidity. This barrel stiffening technique did not completely eliminate barrel movement but the problem was significantly reduced to allow a noticeable accuracy enhancement. This process, although highly successful, came at a very high weight penalty. Obviously the goal would be to lighten the barrel (firearm), yet achieve even greater accuracy. Thus, if lightweight barrels could ultimately be compensated for both their static and dynamic mechanical perturbations, the result would be very accurate, yet significantly lighter weight, weapons. We discuss our development of a barrel reference sensor system that is designed to accomplish this ambitious goal. Our optical fiber-based sensor monitors the barrel muzzle position and autonomously compensates for any induced perturbations. The reticle is electronically adjusted in position to compensate for the induced barrel deviation in real time.

  5. The impact of acceleration on barrel/launch package design

    SciTech Connect

    Ang, J.A. ); Hauze, G. )

    1991-01-01

    This paper discusses the impact of launch acceleration on the design of electromagnetic launcher barrels and on the design of associated launch packages. This is of particular interest because launch package size and mass directly affect the overall armament system size and mass. A common design approach is to use as the peak launch acceleration, the maximum acceleration which the projectile can be designed to withstand. While this approach will minimize barrel length, it may also yield an excessively large overall system size and mass, especially for the long, slender projectile configurations which are desired for high aero-thermal and terminal ballistics performance. An alternate design approach is described which balances the goals of reducing barrel length with reducing launch package mass. Results illustrate the benefits of this balanced design approach on overall armament system size and mass.

  6. Simultaneous visualization of cortical barrels and horseradish peroxidase-injected layer 5b vibrissa neurones in the rat.

    PubMed Central

    Ito, M

    1992-01-01

    1. Using diaminobenzidine (DAB) as a chromagen, horseradish peroxidase-injected neurones and cytochrome oxidase-stained barrels were visualized simultaneously in the rat vibrissa cortex. Neurones were initially tested during extracellular recording for responses to whisker deflections. This was followed by intracellular injection of the soma with horseradish peroxidase (HRP) and histological processing to visualize the HRP-stained neurone in an incubation solution which contained, in addition to DAB, cytochrome C for cytochrome oxidase (CO) reaction of the barrels. 2. Recording and intracellular staining were made in layer 5b under urethane anaesthesia. CO-stained barrels were observed in layer 4. Physiologically and morphologically characterized neurones were mostly large pyramidal neurones that responded to more than one whisker and displayed transient-type responses. 3. In tangential sections, the apical dendrite of the HRP-filled neurone was followed from the soma level upward as it ascended through the barrelfield in layer 4. The cross-section of the apical dendrite was found in the periphery of the CO-stained barrel. Using the apical dendrite as a guide, the basal dendritic field of the layer 5b pyramidal neurone was aligned on the pattern of layer 4 barrels. The soma was seen to project basal dendrites in all directions, involving one or two neighbouring barrels/columns. 4. In sixteen neurones examined in tangential sections, a complete spatial tuning map constructed by measuring sensitivity of the neurone to different whiskers could be compared to the basal dendritic field in relation to the pattern of overlying layer 4 barrels. The mean receptive field size in terms of the number of effective whiskers was 5.8 whereas the mean dendritic field size in terms of the number of barrels/columns involved was 2.2. In addition to the well-documented role of intracortical connectivity in elaboration of multi-whisker receptor fields in the cortical neurones, the role

  7. 14. Interior view, grain tanks (bins). Barrel view of tunnel ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. Interior view, grain tanks (bins). Barrel view of tunnel for load-out belt conveyor system located below tanks. Square, numbered spouts gravity-feed grain from overhead bins onto belt. - Saint Anthony Elevator No. 3, 620 Malcom Avenue, Southeast, Minneapolis, Hennepin County, MN

  8. New results in meson spectroscopy from the crystal barrel experiment

    SciTech Connect

    Meyer, C.A.

    1994-04-01

    Recent observations by the Crystal Barrel experiment of two scalar resonances, f{sub o}(1365) and a{sub o}(1450) have allowed the authors to clarify the members of the scalar nonet. In addition, a third scalar, f{sub o}(1500), appears to be supernumerary, and is a candidate for the scalar glueball expected near 1500 MeV.

  9. 4. AERIAL 'BARREL' SHOT OF THE PATH TRANSIT SYSTEM BRIDGE, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. AERIAL 'BARREL' SHOT OF THE PATH TRANSIT SYSTEM BRIDGE, LOOKING SOUTHEAST TOWARDS JERSEY CITY. TO THE RIGHT ARE THE NEWARK TURNPIKE AND THE CONRAIL BRIDGE (HAER No. NJ-43). THE PULASKI SKYWAY (HAER No. NJ-34) IS IN THE BACKGROUND TO THE RIGHT - Path Transit System Bridge, Spanning Hackensack River, Kearny, Hudson County, NJ

  10. 27 CFR 25.144 - Rebranding barrels and kegs.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... BUREAU, DEPARTMENT OF THE TREASURY LIQUORS BEER Marks, Brands, and Labels § 25.144 Rebranding barrels and... permanently remove or durably cover the original marks and brands after notifying the appropriate TTB officer... the original marks and brands if the brewer: (1) Adopts a trade name substantially identical to...

  11. Centrifugal Barrel Finishing Of Turbine-Blade "Fir Trees"

    NASA Technical Reports Server (NTRS)

    Mandel, Johnny L.

    1990-01-01

    Modified centrifugal barrel-finishing machine imparts desired residual compressive stresses to "fir trees" of turbine blades. Centrifugal forces generate compressive stresses, which are transmitted to turbine blades through abrasive slurries in which suspended. Eliminates need for shot peening, rounding of edges and burrs caused by shot peening and, consequently, need for mass finishing operations to remove burrs. Improves surface finish of "fir trees".

  12. 1. INTERIOR VIEW WITH NAVE, BARREL VAULTED SOLEA, ICONOSTAS WITH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. INTERIOR VIEW WITH NAVE, BARREL VAULTED SOLEA, ICONOSTAS WITH ICON AND SANCTUARY. IN ARCH ABOVE THE SANCTUARY IS THE TABLE OF ABRAHAM. THE ICONOSTAS INCLUDES ICONS OF THE ARCHANGEL MICHAEL, THE HOLY TRINITY, MOTHER OF GOD HOLDING THE CHRIST CHILD, JESUS. - Holy Trinity-Holy Cross Greek Orthodox Church, 200 Nineteenth Street South, Birmingham, Jefferson County, AL

  13. Barrelettes without barrels in the American water shrew.

    PubMed

    Catania, Kenneth C; Catania, Elizabeth H; Sawyer, Eva K; Leitch, Duncan B

    2013-01-01

    Water shrews (Sorex palustris) depend heavily on their elaborate whiskers to navigate their environment and locate prey. They have small eyes and ears with correspondingly small optic and auditory nerves. Previous investigations have shown that water shrew neocortex is dominated by large representations of the whiskers in primary and secondary somatosensory cortex (S1 and S2). Flattened sections of juvenile cortex processed for cytochrome oxidase revealed clear borders of the whisker pad representation in S1, but no cortical barrels. We were therefore surprised to discover prominent barrelettes in brainstem of juvenile water shrews in the present investigation. These distinctive modules were found in the principal trigeminal nucleus (PrV), and in two of the three spinal trigeminal subnuclei (interpolaris--SpVi and caudalis--SpVc). Analysis of the shrew's whisker pad revealed the likely relationship between whiskers and barrelettes. Barrelettes persisted in adult water shrew PrV, but barrels were also absent from adult cortex. Thus in contrast to mice and rats, which have obvious barrels in primary somatosensory cortex and less clear barrelettes in the principal nucleus, water shrews have clear barrelettes in the brainstem and no barrels in the neocortex. These results highlight the diverse ways that similar mechanoreceptors can be represented in the central nervous systems of different species.

  14. 9. Generator Barrel and Rotor of Unit 1, view to ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. Generator Barrel and Rotor of Unit 1, view to the southeast, showing part of the rotor and generator coils along top of photograph and southeast entry stairwell and doors in lower center of photograph. - Washington Water Power Clark Fork River Noxon Rapids Hydroelectric Development, Powerhouse, South bank of Clark Fork River at Noxon Rapids, Noxon, Sanders County, MT

  15. 13. Interior view, grain tanks (bins). Barrel view of overhead ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    13. Interior view, grain tanks (bins). Barrel view of overhead (fill) conveyor gallery bridge extending through tops of tanks just below roofs. Grain tripper straddles belt conveyor at mid-view. - Saint Anthony Elevator No. 3, 620 Malcom Avenue, Southeast, Minneapolis, Hennepin County, MN

  16. VIEW, LOOKING SOUTHWEST OF GOLD AMALGAMATION ROOM, SHOWING AMALGAMATION BARREL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW, LOOKING SOUTHWEST OF GOLD AMALGAMATION ROOM, SHOWING AMALGAMATION BARREL AT CENTER FOREGROUND, BULLION FURNACE IN LARGE HOOD BEHIND IT, AND GOLD RETORT IN BACKGROUND HOOD. NOTE OVERHEAD MONORAIL FOR MATERIALS HANDLING. - Shenandoah-Dives Mill, 135 County Road 2, Silverton, San Juan County, CO

  17. A summary of the BARREL campaigns: Technique for studying electron precipitation.

    PubMed

    Woodger, L A; Halford, A J; Millan, R M; McCarthy, M P; Smith, D M; Bowers, G S; Sample, J G; Anderson, B R; Liang, X

    2015-06-01

    BARREL observed electron precipitation over wide range of energy and timescalesPrecipitating electron distribution is determined using spectroscopy for 19 January 2013 eventBARREL timing data has accuracy within sampling interval of 0.05 s.

  18. Getting Over the Barrel- Achieving Independence from Foreign Oil in 2018

    DTIC Science & Technology

    2009-02-03

    The USGS’s 1998 assessment of area 1002 in the Alaskan National Wildlife Refuge ( ANWR ) estimates there are almost 21 billion barrels of technically...recoverable at $40 a barrel. ANWR area 1002 is expected to produce 780,000 barrels per day in 2018.27 The technological developments in oil...economically recoverable oil. Between them the Outer Continental Shelf, Bakken formation and ANWR area 1002 possess an estimated 109 billion barrels of

  19. Subscale and Full-Scale Testing of Buckling-Critical Launch Vehicle Shell Structures

    NASA Technical Reports Server (NTRS)

    Hilburger, Mark W.; Haynie, Waddy T.; Lovejoy, Andrew E.; Roberts, Michael G.; Norris, Jeffery P.; Waters, W. Allen; Herring, Helen M.

    2012-01-01

    New analysis-based shell buckling design factors (aka knockdown factors), along with associated design and analysis technologies, are being developed by NASA for the design of launch vehicle structures. Preliminary design studies indicate that implementation of these new knockdown factors can enable significant reductions in mass and mass-growth in these vehicles and can help mitigate some of NASA s launch vehicle development and performance risks by reducing the reliance on testing, providing high-fidelity estimates of structural performance, reliability, robustness, and enable increased payload capability. However, in order to validate any new analysis-based design data or methods, a series of carefully designed and executed structural tests are required at both the subscale and full-scale level. This paper describes recent buckling test efforts at NASA on two different orthogrid-stiffened metallic cylindrical shell test articles. One of the test articles was an 8-ft-diameter orthogrid-stiffened cylinder and was subjected to an axial compression load. The second test article was a 27.5-ft-diameter Space Shuttle External Tank-derived cylinder and was subjected to combined internal pressure and axial compression.

  20. The design and performance of a twenty barrel hydrogen pellet injector for Alcator C-Mod

    SciTech Connect

    Urbahn, John A.

    1994-05-01

    A twenty barrel hydrogen pellet injector has been designed, built and tested both in the laboratory and on the Alcator C-Mod Tokamak at MIT. The injector functions by firing pellets of frozen hydrogen or deuterium deep into the plasma discharge for the purpose of fueling the plasma, modifying the density profile and increasing the global energy confinement time. The design goals of the injector are: (1) Operational flexibility, (2) High reliability, (3) Remote operation with minimal maintenance. These requirements have lead to a single stage, pipe gun design with twenty barrels. Pellets are formed by in- situ condensation of the fuel gas, thus avoiding moving parts at cryogenic temperatures. The injector is the first to dispense with the need for cryogenic fluids and instead uses a closed cycle refrigerator to cool the thermal system components. The twenty barrels of the injector produce pellets of four different size groups and allow for a high degree of flexibility in fueling experiments. Operation of the injector is under PLC control allowing for remote operation, interlocked safety features and automated pellet manufacturing. The injector has been extrusively tested and shown to produce pellets reliably with velocities up to 1400 m/sec. During the period from September to November of 1993, the injector was successfully used to fire pellets into over fifty plasma discharges. Experimental results include data on the pellet penetration into the plasma using an advanced pellet tracking diagnostic with improved time and spatial response. Data from the tracker indicates pellet penetrations were between 30 and 86 percent of the plasma minor radius.

  1. Resilience to disturbance despite limited dispersal and self-recruitment in tropical barrel sponges: implications for conservation and management.

    PubMed

    Bell, James J; Smith, David; Hannan, Danielle; Haris, Abdul; Jompa, Jamaludin; Thomas, Luke

    2014-01-01

    While estimates of connectivity are important for effective management, few such estimates are available for reef invertebrates other than for corals. Barrel sponges are one of the largest and most conspicuous members of the coral reef fauna across the Indo-Pacific and given their large size, longevity and ability to process large volumes of water, they have a major role in reef functioning. Here we used a panel of microsatellite markers to characterise the genetic structure of two barrel sponge species, Xestospongia testudinaria and a currently undescribed Xestospongia species. We sampled across seven populations in the Wakatobi Marine National Park, SE Sulawesi (Indonesia) spanning a spatial scale of approximately 2 to 70 km, and present the first estimates of demographic connectivity for coral reef sponges. Genetic analyses showed high levels of genetic differentiation between all populations for both species, but contrasting patterns of genetic structuring for the two species. Autocorrelation analyses showed the likely dispersal distances of both species to be in the order of 60 and 140 m for Xestopongia sp. and Xestospongia testudinaria, respectively, which was supported by assignment tests that showed high levels of self-recruitment (>80%). We also found consistently high inbreeding coefficients across all populations for both species. Our study highlights the potential susceptibility of barrel sponges to environmental perturbations because they are generally long-lived, slow growing, have small population sizes and are likely to be reliant on self-recruitment. Surprisingly, despite these features we actually found the highest abundance of both barrel sponge species (although they were generally smaller) at a site that has been severely impacted by humans over the last fifty years. This suggests that barrel sponges exhibit environmental adaptation to declining environmental quality and has important implications for the management and conservation of these

  2. Triple-barrel aorta: dissection of a healed aortic dissection.

    PubMed

    Lie, J T

    1982-08-01

    An unusual case of a triple-barrel aorta in a 51-year-old woman is described. The patient first had a spontaneous type I dissection of the aorta and acute aortic insufficiency, for which she underwent aortic valve replacement and Dacron graft replacement of the ascending aorta. She remained asymptomatic for five years with a healed aortic dissection (double-barrel aorta) distal to the graft. She then underwent a second operation for repair and poppet replacement of the malfunctioned prosthesis. Postoperative cardiac failure necessitated the use of a counterpulsation intra-aortic balloon catheter, which entered and dissected the wall of the false lumen, thus creating a triple-lumen aorta.

  3. Barrel cortex membrane potential dynamics in social touch.

    PubMed

    Lenschow, Constanze; Brecht, Michael

    2015-02-18

    The impact of social stimuli on the membrane potential dynamics of barrel cortex neurons is unknown. We obtained in vivo whole-cell recordings in the barrel cortex of head-restrained rats while they interacted with conspecifics. Social touch was associated with a depolarization and large membrane potential fluctuations locked to the rat's whisking. Both depolarization and membrane potential fluctuations were already observed prior to contact and did not occur during free whisking. This anticipatory pre-contact depolarization was not seen in passive social touch in anesthetized animals. The membrane potential fluctuations locked to the rat's whisking observed in interactions with awake conspecifics were larger than those seen for whisking onto nonconspecific stimuli (stuffed rats, objects, and the experimenter's hand). Responses did not correlate with whisker movement parameters. We conclude that responses to social touch differ from conventional tactile responses in (1) amplitude, (2) locking to whisking, and (3) pre-contact membrane potential changes.

  4. Simulation and reconstruction of the PANDA Barrel DIRC

    NASA Astrophysics Data System (ADS)

    Dzhygadlo, R.; Gerhardt, A.; Go¨tzen, K.; Hohler, R.; Kalicy, G.; Kumawat, H.; Lehmann, D.; Lewandowski, B.; Patsyuk, M.; Peters, K.; Schepers, G.; Schmitt, L.; Schwarz, C.; Schwiening, J.; Traxler, M.; Zühlsdorf, M.; Dodokhov, V. Kh.; Britting, A.; Eyrich, W.; Lehmann, A.; Uhlig, F.; Düren, M.; Fo¨hl, K.; Hayrapetyan, A.; Kro¨ck, B.; Merle, O.; Rieke, J.; Cowie, E.; Keri, T.; Montgomery, R.; Rosner, G.; Achenbach, P.; Cardinali, M.; Hoek, M.; Lauth, W.; Sfienti, C.; Thiel, M.; Bühler, P.; Gruber, L.; Marton, J.; Suzuki, K.

    2014-12-01

    Hadronic particle identification (PID) in the barrel region of the PANDA experiment at the new Facility for Antiproton and Ion Research in Europe (FAIR) at GSI, Darmstadt will be provided by a DIRC (Detection of Internally Reflected Cherenkov light) counter. To optimize the performance and reduce the detector cost, detailed simulations of different design elements, such as the width of the radiators, the shape of the expansion volume, and the type of focusing system, were performed using Geant. Custom reconstruction algorithms were developed to match the detector geometry. We will discuss the single photon resolution and photon yield as well as the PID performance for the Barrel DIRC baseline design and several detector design options.

  5. Upgrade of the CMS muon trigger system in the barrel region

    NASA Astrophysics Data System (ADS)

    Rabady, Dinyar; Ero, Janos; Flouris, Giannis; Fulcher, Jonathan; Loukas, Nikitas; Paradas, Evangelos; Reis, Thomas; Sakulin, Hannes; Wulz, Claudia-Elisabeth

    2017-02-01

    To maintain the excellent performance shown during the LHC's Run-1 the Level-1 Trigger of the Compact Muon Solenoid experiment underwent a significant upgrade. One part of this upgrade is the re-organization of the muon trigger path from a subsystem-centric view in which hits in the drift tubes (DT), the cathode strip chambers (CSC), and the resistive plate chambers (RPC) were treated separately in dedicated track-finding systems to one in which complementary detector systems for a given region (barrel, overlap, and endcap) are merged at the track-finding level. This fundamental restructuring of the muon trigger system required the development of a system to receive track candidates from the track-finding layer, remove potential duplicate tracks, and forward the best candidates to the global decision layer. An overview will be given of the new track-finder system for the barrel region, the Barrel Muon Track Finder (BMTF), as well as the cancel-out and sorting layer: the upgraded Global Muon Trigger (μGMT). Both the BMTF and μGMT have been implemented in a Xilinx Virtex-7 card utilizing the microTCA architecture. While the BMTF improves on the proven and well-tested algorithms used in the Drift Tube Track Finder during Run-1, the μGMT is an almost complete re-development due to the re-organization of the underlying systems from track-finders for a specific detector to regional track finders covering a given area of the whole detector. Additionally the μGMT calculates a muon's isolation using energy information received from the calorimeter trigger. This information is added to the muon objects forwarded to the global decision layer, the so-called Global Trigger.

  6. Refractory Metal Liner Processing for M242 Medium Caliber Barrels

    DTIC Science & Technology

    2013-01-01

    public release; distribution unlimited. 13. SUPPLEMENTARY NOTES 14. ABSTRACT The process for attaching a refractory metal liner to a gun tube...known as Gun Liner Emplacement with an Elastomeric Material (GLEEM) has been developed for the 25 mm Bushmaster medium caliber cannon. Stellite 25 liners...liner stretching. 15. SUBJECT TERMS refractory metal, gun tube liner, M242 barrel, elastomer, liner processing 16. SECURITY CLASSIFICATION OF: 17

  7. Cellular organization of cortical barrel columns is whisker-specific.

    PubMed

    Meyer, Hanno S; Egger, Robert; Guest, Jason M; Foerster, Rita; Reissl, Stefan; Oberlaender, Marcel

    2013-11-19

    The cellular organization of the cortex is of fundamental importance for elucidating the structural principles that underlie its functions. It has been suggested that reconstructing the structure and synaptic wiring of the elementary functional building block of mammalian cortices, the cortical column, might suffice to reverse engineer and simulate the functions of entire cortices. In the vibrissal area of rodent somatosensory cortex, whisker-related "barrel" columns have been referred to as potential cytoarchitectonic equivalents of functional cortical columns. Here, we investigated the structural stereotypy of cortical barrel columns by measuring the 3D neuronal composition of the entire vibrissal area in rat somatosensory cortex and thalamus. We found that the number of neurons per cortical barrel column and thalamic "barreloid" varied substantially within individual animals, increasing by ∼2.5-fold from dorsal to ventral whiskers. As a result, the ratio between whisker-specific thalamic and cortical neurons was remarkably constant. Thus, we hypothesize that the cellular architecture of sensory cortices reflects the degree of similarity in sensory input and not columnar and/or cortical uniformity principles.

  8. Development and Critical Period Plasticity of the Barrel Cortex

    PubMed Central

    Erzurumlu, Reha S.; Gaspar, Patricia

    2012-01-01

    In primary sensory neocortical areas of the mammals, the distribution of sensory receptors is mapped with topographic precision and amplification in proportion to the peripheral receptor density. The visual, somatosensory and auditory cortical maps are established during a critical period in development. Throughout this window in time, the developing cortical maps are vulnerable to deleterious effects of sense organ damage or sensory deprivation. The rodent barrel cortex offers an invaluable model system to investigate mechanisms underlying the formation of topographic maps and their plasticity during development. Five rows of mystacial vibrissa (whisker) follicles on the snout and an array of sinus hairs are represented by layer IV neural modules (“barrels”) and thalamocortical axon terminals in the primary somatosensory cortex. Perinatal damage to the whiskers or the sensory nerve innervating them irreversibly alters the structural organization of the barrels. Earlier studies emphasized the role of sensory periphery in dictating whisker-specific brain maps and patterns. Recent advances in molecular genetics and analyses of genetically altered mice allow new insights into neural pattern formation in the neocortex and the mechanisms underlying critical period plasticity. Here we review the development and patterning of the barrel cortex and the critical period plasticity. PMID:22607000

  9. The representation of social facial touch in rat barrel cortex.

    PubMed

    Bobrov, Evgeny; Wolfe, Jason; Rao, Rajnish P; Brecht, Michael

    2014-01-06

    Controlled presentation of stimuli to anesthetized [1] or awake [2] animals suggested that neurons in sensory cortices respond to elementary features [3, 4], but we know little about neuronal responses evoked by social interactions. Here we investigate processing in the barrel cortex of rats engaging in social facial touch [5, 6]. Sensory stimulation by conspecifics differs from classic whisker stimuli such as deflections, contact poles [7, 8], or textures [9, 10]. A large fraction of barrel cortex neurons responded to facial touch. Social touch responses peaked when animals aligned their faces and contacted each other by multiple whiskers with small, irregular whisker movements. Object touch was associated with larger, more regular whisker movements, and object responses were weaker than social responses. Whisker trimming abolished responses. During social touch, neurons in males increased their firing on average by 44%, while neurons in females increased their firing by only 19%. In females, socially evoked and ongoing firing rates were more than 1.5-fold higher in nonestrus than in estrus. Barrel cortex represented socially different contacts by distinct firing rates, and the variation of activity with sex and sexual status could contribute to the generation of gender-specific neural constructs of conspecifics.

  10. Rapid, learning-induced inhibitory synaptogenesis in murine barrel field

    PubMed Central

    Jasinska, M.; Siucinska, E.; Cybulska-Klosowicz, A.; Pyza, E.; Furness, D.N.; Kossut, M.; Glazewski, S.

    2010-01-01

    The structure of neurones changes during development and in response to injury or alteration in sensory experience. Changes occur in the number, shape and dimensions of dendritic spines together with their synapses. However, precise data on these changes in response to learning are sparse. Here, we show using quantitative transmission electron microscopy that a simple form of learning involving mystacial vibrissae results in about 70% increase in the density of inhibitory synapses on spines of neurones located in layer IV barrels that represent the stimulated vibrissae. The spines contain one asymmetrical (excitatory) and one symmetrical (inhibitory) synapse (double-synapse spines) and their density increases 3-fold due to learning with no apparent change in the density of asymmetrical synapses. This effect seems to be specific for learning as pseudoconditioning (where the conditioned and unconditioned stimuli are delivered at random) does not lead to the enhancement of symmetrical synapses, but instead results in an up-regulation of asymmetrical synapses on spines. Symmetrical synapses of cells located in barrels receiving the conditioned stimulus show also a greater concentration of γ-amino-butyric acid (GABA) in their presynaptic terminals. These results indicate that the immediate effect of classical conditioning in the ‘conditioned’ barrels is rapid, pronounced and inhibitory. PMID:20089926

  11. The barrel DIRC detector for the P¯ ANDA experiment at FAIR

    NASA Astrophysics Data System (ADS)

    Schwiening, J.; P¯ Group; ANDA Cherenkov Group

    2011-05-01

    The P¯ANDA experiment at FAIR will perform high precision experiments in the charmed quark sector using cooled antiproton beams of unprecedented intensities of L=2×10 32 cm -2 s -1 in the momentum range of 1-15 GeV/ c. The charged particle identification in the barrel region needs a thin detector operating in a strong magnetic field. A ring imaging Cherenkov detector using the DIRC principle is an excellent match to those requirements. This article describes aspects of the design and R&D for the P¯ANDA barrel DIRC detector. The availability of highly pixelated fast photon detectors allows several key improvements compared to the successful BaBar-DIRC detector, some of which were tested in a proton beam at GSI. The optical properties of the radiator bars, made from synthetic fused silica, are critical to the success of the DIRC. Measurements of the attenuation length and reflection coefficient allow the determination of the surface roughness of prototype radiator bars.

  12. Modeling Beta-Traces for Beta-Barrels from Cryo-EM Density Maps.

    PubMed

    Si, Dong; He, Jing

    2017-01-01

    Cryo-electron microscopy (cryo-EM) has produced density maps of various resolutions. Although α-helices can be detected from density maps at 5-8 Å resolutions, β-strands are challenging to detect at such density maps due to close-spacing of β-strands. The variety of shapes of β-sheets adds the complexity of β-strands detection from density maps. We propose a new approach to model traces of β-strands for β-barrel density regions that are extracted from cryo-EM density maps. In the test containing eight β-barrels extracted from experimental cryo-EM density maps at 5.5 Å-8.25 Å resolution, StrandRoller detected about 74.26% of the amino acids in the β-strands with an overall 2.05 Å 2-way distance between the detected β-traces and the observed ones, if the best of the fifteen detection cases is considered.

  13. Modeling Beta-Traces for Beta-Barrels from Cryo-EM Density Maps

    PubMed Central

    Si, Dong

    2017-01-01

    Cryo-electron microscopy (cryo-EM) has produced density maps of various resolutions. Although α-helices can be detected from density maps at 5–8 Å resolutions, β-strands are challenging to detect at such density maps due to close-spacing of β-strands. The variety of shapes of β-sheets adds the complexity of β-strands detection from density maps. We propose a new approach to model traces of β-strands for β-barrel density regions that are extracted from cryo-EM density maps. In the test containing eight β-barrels extracted from experimental cryo-EM density maps at 5.5 Å–8.25 Å resolution, StrandRoller detected about 74.26% of the amino acids in the β-strands with an overall 2.05 Å 2-way distance between the detected β-traces and the observed ones, if the best of the fifteen detection cases is considered. PMID:28164115

  14. Recent advances in the evaluation of the oxygen transfer rate in oak barrels.

    PubMed

    del Alamo-Sanza, María; Nevares, Ignacio

    2014-09-03

    The entry of atmospheric oxygen into wine barrels is a desirable characteristic of the wine aging process. The oxygen transfer rate regulates changes in wine affecting aging rates because some barrels may undergo a greater wine oxygenation. This study measured the transfer rate and oxygen distribution within a barrel. The analysis confirmed the presence of a dissolved oxygen concentration gradient in the liquid, with greater concentrations near the bung. The study of the transfer rate of oxygen over time, in 12 barrels of different types, showed that wetting wood reduces oxygen diffusion and the oxygen transfer rate (OTR). These results are the first to determine the kinetics of oxygen entry into wine barrels and can be used to quantify the annual rate of oxygen entry into wine barrels.

  15. Barrel maturation, oak alternatives and micro-oxygenation: influence on red wine aging and quality.

    PubMed

    Oberholster, A; Elmendorf, B L; Lerno, L A; King, E S; Heymann, H; Brenneman, C E; Boulton, R B

    2015-04-15

    The impact of micro-oxygenation (MOX) in conjunction with a variety of oak alternatives on phenolic composition and red wine aging was investigated and compared with traditional barrel aging. Although several studies concluded that MOX give similar results to barrel aging, few have compared them directly and none directly compared MOX with and without wood alternatives and barrel aging. Results confirmed that MOX had a positive effect on colour density, even after 5 months of bottle aging. This is supported by an increase in polymeric phenol and pigment content not only with aging but in the MOX compared to barrel matured wine treatments. Descriptive analysis showed that MOX in combination with wood alternatives such as oak chips and staves could mimic short term (six months) barrel aging in new American and French oak barrels in regards to sensory characteristics.

  16. Repair of Erosion Defects in Gun Barrels by Direct Laser Deposition

    NASA Astrophysics Data System (ADS)

    Nowotny, Steffen; Spatzier, Joerg; Kubisch, Frank; Scharek, Siegfried; Ortner, Jens; Beyer, Eckhard

    2012-12-01

    In recent years the development of functional carbide coatings follows the trend to use composite powders with fine grained hard particles. In addition to thermal spraying, laser cladding is a suitable surface technology in particular for dynamically loaded components, and it is widely used for the manufacturing of coatings as well as complex 3D structures. The paper presents an application addressing the repair of erosion defects in large gun barrels using a novel internal diameter laser cladding head. The most promising material systems are TiC- and VC-based metal-matrix composites. Samples were evaluated in a special erosion test that emulates realistic load conditions. In this test, the materials are exposed to extreme stresses by temperature and pressure shocks, a very reactive atmosphere and erosive particles. As result, TiC-based coatings showed the best performance, and they are applicable for both repair and surface protection of inner surfaces of components and tools.

  17. Processing of Niobium-Lined M240 Machine Gun Barrels

    DTIC Science & Technology

    2014-11-01

    produce at least a 0.001 inch (0.025 mm) expansion of the steel cylinder to allow the mandrel to fit inside the liner . The other dimensions were...barrel blank and niobium liner is shown in Fig. 2. 4 Fig. 2 Gun tube and niobium- liner hardware 3. Experimental Approach 3.1 Load Cylinder ...The load cylinder outer diameter was taken to be 0.308 inch (7.82 mm), giving enough clearance between it and the niobium liner to ensure easy

  18. Innovative active control of gun barrels using smart materials

    NASA Astrophysics Data System (ADS)

    Mattice, Michael S.; LaVigna, Chris

    1997-06-01

    The accuracy of stabilized, turreted gun systems like the 120mm gun on the M1A2 Abrams tank and the 30mm gun on the Apache helicopter are limited by, among other things, structural flexure of the gun barrel and support structure. An advanced actuation system based on piezoelectric translators and an optical fiber strain sensing system are described in conjunction with a rapid prototyping workstation for the design of distributed parameter control systems to actively minimize the effects of vibrations caused by traversing rough terrain or weapon firing.

  19. Optical System of the STAR Barrel Electromagnetic Calorimeter

    NASA Astrophysics Data System (ADS)

    Grachov, O. A.

    2000-04-01

    The STAR Barrel Electromagnetic Calorimeter(BEMC) is a sampling calorimeter and the core of structure consist of a lead-scintillator plate stack. The plastic scintillator in the form of Mega-tile with 40 optically isolated tiles in each layer. The tile/fiber system uses a wavelength shifting fiber to read out the signal of a tile and a optical clear fiber carry the light through the magnet structure to the electronic-PMT box. A discription of the Optical system of BEMC is presented along with a current status of the quality control program of the calorimeter production.

  20. Theoretical Exploration of Barrel-Shaped Drops on Cactus Spines.

    PubMed

    Luo, Cheng

    2015-11-03

    To survive an arid environment, desert cacti are capable of harvesting water from fog by transporting condensed water drops using their spines. Cactus spines have a conical shape. In this work, on the basis of the difference of liquid pressure, a new theoretical model has been developed for a barrel-shaped liquid drop on a conical wire. This model is further simplified to interpret the effects of contact angles, conical angle, surface microgrooves, and gravity on the drop movement along a cactus spine.

  1. Creation of active TIM barrel enzymes through genetic fusion of half-barrel domain constructs derived from two distantly related glycosyl hydrolases.

    PubMed

    Sharma, Prerna; Kaila, Pallavi; Guptasarma, Purnananda

    2016-12-01

    Diverse unrelated enzymes that adopt the beta/alpha (or TIM) barrel topology display similar arrangements of beta/alpha units placed in a radial eight-fold symmetry around the barrel's axis. The TIM barrel was originally thought to be a single structural domain; however, it is now thought that TIM barrels arose from duplication and fusion of smaller half-barrels consisting of four beta/alpha units. We describe here the design, expression and purification, as well as characterization of folding, activity and stability, of chimeras of two TIM barrel glycosyl hydrolases, made by fusing different half-barrel domains derived from an endoglucanase from Clostridium cellulolyticum, CelCCA and a beta-glucosidase from Pyrococcus furiosus, CelB. We show that after refolding following purification from inclusion bodies, the two half-barrel fusion chimeras (CelCCACelB and CelBCelCCA) display catalytic activity although they assemble into large soluble oligomeric aggregated species containing chains of mixed beta and alpha structure. CelBCelCCA displays hyperthermophile-like structural stability as well as significant stability to chemical denaturation (Cm of 2.6 m guanidinium hydrochloride), whereas CelCCACelB displays mesophile-like stability (Tm of ~ 71 °C). The endoglucanase activities of both chimeras are an order of magnitude lower than those of CelB or CelCCA, whereas the beta-glucosidase activity of CelBCelCCA is about two orders of magnitude lower than that of CelB. The chimera CelCCACelB shows no beta-glucosidase activity. Our results demonstrate that half-barrel domains from unrelated sources can fold, assemble and function, with scope for improvement.

  2. Oak Stave Oxygen Permeation: A New Tool To Make Barrels with Different Wine Oxygenation Potentials.

    PubMed

    Nevares, Ignacio; Del Alamo-Sanza, María

    2015-01-22

    The aim of this study was to classify rough staves according to their permeability to oxygen by measuring their transmission rate to assess the capacity to build barrels with high and low oxygen transmission rates (OTRs). The ability to assess the OTR would be important for better understanding and controlling the aging process of wine in barrels. To accomplish this, we built a device that measures the OTR of rough staves under the same conditions as those in a full barrel, in which the stave is in contact with a liquid solution on one face and with a diffusing gas on the opposite face. A total of 69 rough staves were classified to yield a high-OTR group, with a mean 2.6 times higher than the mean of the low-OTR group. A high-OTR barrel and a low-OTR barrel were constructed, and we confirmed that the stave OTR decreased between 3- and 4.5-fold in the barrels and that the high-OTR barrel allowed the entry of twice the concentration of oxygen compared to the low-OTR barrel. These results confirmed the capacity to classify rough staves and build barrels with different OTRs.

  3. Parallel access alignment network with barrel switch implementation for d-ordered vector elements

    NASA Technical Reports Server (NTRS)

    Barnes, George H. (Inventor)

    1980-01-01

    An alignment network between N parallel data input ports and N parallel data outputs includes a first and a second barrel switch. The first barrel switch fed by the N parallel input ports shifts the N outputs thereof and in turn feeds the N-1 input data paths of the second barrel switch according to the relationship X=k.sup.y modulo N wherein x represents the output data path ordering of the first barrel switch, y represents the input data path ordering of the second barrel switch, and k equals a primitive root of the number N. The zero (0) ordered output data path of the first barrel switch is fed directly to the zero ordered output port. The N-1 output data paths of the second barrel switch are connected to the N output ports in the reverse ordering of the connections between the output data paths of the first barrel switch and the input data paths of the second barrel switch. The second switch is controlled by a value m, which in the preferred embodiment is produced at the output of a ROM addressed by the value d wherein d represents the incremental spacing or distance between data elements to be accessed from the N input ports, and m is generated therefrom according to the relationship d=k.sup.m modulo N.

  4. Dynamic response of a lightweight gun barrel during a firing-pressure transient

    SciTech Connect

    McGrath, S.V.; Phillips, L.P. Jr.

    1990-04-01

    This report presents the results of a nonlinear, dynamic structural analysis of a gun barrel design during a firing-pressure transient. The final design was defined by an iterative design/analysis process in which the effects of design modifications were compared with established design criteria. The ADINA finite element code was used to analyze the titanium/carbon composite gun barrel assembly for a maximum transient pressure of 29,000 psi. The gun barrel weighs 42 lb; however, a significant potential exists for weight savings in future gun barrel designs. 2 refs., 41 figs.

  5. Double Barrel In Situ Recanalization of Thrombosed Nonretrievable IVC filter.

    PubMed

    Banerjee, Shubhabrata; Patel, Hiten M; Sheorain, Virender K; Grover, Tarun; Parakh, Rajiv

    2016-05-01

    We report a case of endovascular recanalization of complete thrombotic occlusion of the inferior vena cava (IVC) and bilateral iliac veins using the architectural knowledge of the in situ permanent IVC filter in a 23-year-old male. The infrarenal permanent IVC filter was TRAPEASE permanent vena cava filter (Cordis) placed at an outstation hospital for pulmonary embolism. Being permanent variant of filter, percutaneous removal was not possible. The patient had severe venous claudication and an attempt to recanalize the blocked filter was considered, in view of the age no justifiable indication for a long-term filter. After pharmacomechanical catheter-directed thrombolysis, there was residual focal flow-limiting thrombus within the filter. The design of the Trapease Cordis filter was instrumental in our decision to attempt to recanalize the filter in situ using 2 parallel stents with the filter struts as anchoring pillars in a double-barrel alignment. In similar cases of persistent Trapease filter-related thrombotic occlusion of the IVC, this double barrel in situ recanalization shall be a viable alternative to the well-described technique of crushing the filter and recanalizing it with a single stent.

  6. EMIC Waves Observed in Conjunction with BARREL Electron Precipitation

    NASA Astrophysics Data System (ADS)

    Weaver, C.; Engebretson, M. J.; Lessard, M.; Halford, A. J.; Millan, R. M.; Horne, R. B.; Singer, H. J.

    2013-05-01

    Electromagnetic ion-cyclotron (EMIC) waves have been detected at Halley, Antarctica coinciding with observations of electron precipitation on high altitude balloons from the Balloon Array for RBSP Relativistic Electron Losses (BARREL) campaign launched in early 2013 from SANAE IV and Halley Station. The balloons were launched such that both spatial and temporal properties of electron precipitation might be examined. With a magnetic foot point mapped to the radiation belts, Halley is an ideal location to capture ground based signatures that coincide with electron precipitation. EMIC waves have been shown, both theoretically and through statistical surveys, to pitch angle scatter energetic protons and relativistic electrons via cyclotron resonance and contribute to radiation belt dynamics. EMIC waves were detected at Halley Station 23 times from 12 Jan - 4 Feb with 17 of those waves occurring during times when at least one BARREL balloon observed precipitation in one or more energy channels. High resolution magnetometer data from GOES 13 (which has a magnetic foot point near WAIS Divide, Antarctica-located about 2.5 hours, in MLT, west of Halley) show similar EMIC wave structure and frequency to 9 waves observed at Halley, suggesting the source region extended to at least the longitude and L value of GOES 13 during some events. The ground observed waves appeared in all local times and during both quiet and disturbed intervals.

  7. Dosimetry assessments for the reactor pressure vessel and core barrel in UK PWR plant

    SciTech Connect

    Thornton, D.A.; Allen, D.A.; Huggon, A.P.; Picton, D.J.; Robinson, A.T.; Steadman, R.J.; Seren, T.; Lipponen, M.; Kekki, T.

    2011-07-01

    Specimens for the Sizewell B reactor pressure vessel (RPV) inservice steels surveillance program are irradiated inside eight capsules located within the reactor pressure vessel and loaded prior to commissioning. The periodic removal of these capsules and testing of their contents provides material properties data at intervals during the lifetime of the plant. Neutron activation measurements and radiation transport calculations play an essential role in assessing the neutron exposure of the specimens and RPV. Following the most recent withdrawal, seven capsules have now been removed covering nine cycles of reactor operation. This paper summarizes the dosimetry results of the Sizewell B surveillance program obtained to date. In addition to an overview of the calculational methodology it includes a review of the measurements. Finally, it describes an extension of the methodology to provide dosimetry recommendations for the core barrel and briefly discusses the results that were obtained. (authors)

  8. Tapered laser rods as a means of minimizing the path length of trapped barrel mode rays

    DOEpatents

    Beach, Raymond J.; Honea, Eric C.; Payne, Stephen A.; Mercer, Ian; Perry, Michael D.

    2005-08-30

    By tapering the diameter of a flanged barrel laser rod over its length, the maximum trapped path length of a barrel mode can be dramatically reduced, thereby reducing the ability of the trapped spontaneous emission to negatively impact laser performance through amplified spontaneous emission (ASE). Laser rods with polished barrels and flanged end caps have found increasing application in diode array end-pumped laser systems. The polished barrel of the rod serves to confine diode array pump light within the rod. In systems utilizing an end-pumping geometry and such polished barrel laser rods, the pump light that is introduced into one or both ends of the laser rod, is ducted down the length of the rod via the total internal reflections (TIRs) that occur when the light strikes the rod's barrel. A disadvantage of using polished barrel laser rods is that such rods are very susceptible to barrel mode paths that can trap spontaneous emission over long path lengths. This trapped spontaneous emission can then be amplified through stimulated emission resulting in a situation where the stored energy available to the desired lasing mode is effectively depleted, which then negatively impacts the laser's performance, a result that is effectively reduced by introducing a taper onto the laser rod.

  9. Performance of the ATLAS electromagnetic calorimeter barrel module 0

    NASA Astrophysics Data System (ADS)

    Aubert, B.; Ballansat, J.; Bazan, A.; Beaugiraud, B.; Boniface, J.; Chollet, F.; Colas, J.; Delebecque, P.; di Ciaccio, L.; Dumont-Dayot, N.; El Kacimi, M.; Gaumer, O.; Ghez, P.; Girard, C.; Gouanère, M.; Kambara, H.; Jérémie, A.; Jézéquel, S.; Lafaye, R.; Leflour, T.; Le Maner, C.; Lesueur, J.; Massol, N.; Moynot, M.; Neukermans, L.; Perrodo, P.; Perrot, G.; Poggioli, L.; Prast, J.; Przysiezniak, H.; Riccadona, X.; Sauvage, G.; Thion, J.; Wingerter-Seez, I.; Zitoun, R.; Zolnierowski, Y.; Chen, H.; Citterio, M.; Farrell, J.; Gordon, H.; Hackenburg, B.; Hoffman, A.; Kierstead, J.; Lanni, F.; Leite, M.; Lissauer, D.; Ma, H.; Makowiecki, D.; Radeka, V.; Rahm, D.; Rajagopalan, S.; Rescia, S.; Stumer, I.; Takai, H.; Yip, K.; Benchekroun, D.; Driouichi, C.; Hoummada, A.; Hakimi, M.; Stroynowski, R.; Ye, J.; Beck Hansen, J.; Belymam, A.; Bremer, J.; Chevalley, J. L.; Fassnacht, P.; Gianotti, F.; Hervas, L.; Marin, C. P.; Pailler, P.; Schilly, P.; Seidl, W.; Vossebeld, J.; Vuillemin, V.; Clark, A.; Efthymiopoulos, I.; Moneta, L.; Belhorma, B.; Collot, J.; de Saintignon, P.; Dzahini, D.; Ferrari, A.; Gallin-Martel, M. L.; Hostachy, J. Y.; Martin, P.; Muraz, J. F.; Ohlsson-Malek, F.; Saboumazrag, S.; Ban, J.; Cartiglia, N.; Cunitz, H.; Dodd, J.; Gara, A.; Leltchouk, M.; Negroni, S.; Parsons, J. A.; Seman, M.; Simion, S.; Sippach, W.; Willis, W.; Barreiro, F.; Garcia, G.; Labarga, L.; Rodier, S.; Del Peso, J.; Alexa, C.; Barrillon, P.; Benchouk, C.; Chekhtman, A.; Dinkespiler, B.; Djama, F.; Duval, P. Y.; Henry-Couannier, F.; Hinz, L.; Jevaud, M.; Karst, P.; Le van Suu, A.; Martin, L.; Martin, O.; Mirea, A.; Monnier, E.; Nagy, E.; Nicod, D.; Olivier, C.; Pralavorio, P.; Repetti, B.; Raymond, M.; Sauvage, D.; Tisserant, S.; Toth, J.; Wielers, M.; Battistoni, G.; Bonivento, W.; Carminati, L.; Cavalli, D.; Costa, G.; Delmastro, M.; Fanti, M.; Mandelli, L.; Mazzanti, M.; Perini, L.; Resconi, S.; Tartarelli, G. F.; Aulchenko, V.; Kazanin, V.; Kolachev, G.; Malyshev, V.; Maslennikov, A.; Pospelov, G.; Snopkov, R.; Shousharo, A.; Talyshev, A.; Tikhonov, Yu.; Augé, E.; Bourdarios, C.; Breton, D.; Cros, P.; de La Taille, C.; Falleau, I.; Fournier, D.; Guilhem, G.; Hassani, S.; Jacquier, Y.; Kordas, K.; Macé, G.; Merkel, B.; Noppe, J. M.; Parrour, G.; Pétroff, P.; Puzo, P.; Richer, J. P.; Rousseau, D.; Seguin-Moreau, N.; Serin, L.; Tocut, V.; Veillet, J. J.; Zerwas, D.; Astesan, F.; Bertoli, W.; Camard, A.; Canton, B.; Fichet, S.; Hubaut, F.; Imbault, D.; Lacour, D.; Laforge, B.; Le Dortz, O.; Martin, D.; Nikolic-Audit, I.; Orsini, F.; Rossel, F.; Schwemling, P.; Cleland, W.; McDonald, J.; Abouelouafa, E. M.; Ben Mansour, A.; Cherkaoui, R.; El Mouahhidi, Y.; Ghazlane, H.; Idrissi, A.; Belorgey, J.; Bernard, R.; Chalifour, M.; Le Coroller, A.; Ernwein, J.; Mansoulié, B.; Renardy, J. F.; Schwindling, J.; Taguet, J.-P.; Teiger, J.; Clément, C.; Lund-Jensen, B.; Lundqvist, J.; Megner, L.; Pearce, M.; Rydstrom, S.; Egdemir, J.; Engelmann, R.; Hoffman, J.; McCarthy, R.; Rijssenbeek, M.; Steffens, J.; Atlas Electromagnetic Liquid Argon Calorimeter Group

    2003-03-01

    The construction and performance of the barrel pre-series module 0 of the future ATLAS electromagnetic calorimeter at the LHC is described. The signal reconstruction and performance of ATLAS-like electronics has been studied. The signal to noise ratio for muons has been found to be 7.11±0.07. An energy resolution of better than 9.5% GeV1/2/ E (sampling term) has been obtained with electron beams of up to 245 GeV. The uniformity of the response to electrons in an area of Δ η×Δ φ=1.2×0.075 has been measured to be better than 0.8%.

  10. Modeling of gun barrel surface erosion: Historic perspective

    SciTech Connect

    Buckingham, A.C.

    1996-08-01

    Results and interpretations of numerical simulations of some dominant processes influencing gun barrel propellant combustion and flow-induced erosion are presented. Results include modeled influences of erosion reduction techniques such as solid additives, vapor phase chemical modifications, and alteration of surface solid composition through use of thin coatings. Precedents and historical perspective are provided with predictions from traditional interior ballistics compared to computer simulations. Accelerating reactive combustion flow, multiphase and multicomponent transport, flow-to-surface thermal/momentum/phase change/gas-surface chemical exchanges, surface and micro-depth subsurface heating/stress/composition evolution and their roles in inducing surface cracking, spall, ablation, melting, and vaporization are considered. Recognition is given to cyclic effects of previous firing history on material preconditioning. Current perspective and outlook for future are based on results of a US Army-LLNL erosion research program covering 7 y in late 1970s. This is supplemented by more recent research on hypervelocity electromagnetic projectile launchers.

  11. Alcohol dehydrogenase polymorphism in barrel cactus populations of Drosophila mojavensis.

    PubMed

    Cleland, S; Hocutt, G D; Breitmeyer, C M; Markow, T A; Pfeiler, E

    1996-07-01

    Starch gel electrophoresis revealed that the alcohol dehydrogenase (ADH-2) locus was polymorphic in two populations (from Agua Caliente, California and the Grand Canyon, Arizona) of cactophilic Drosophila mojavensis that utilize barrel cactus (Ferocactus acanthodes) as a host plant. Electromorphs representing products of a slow (S) and a fast (F) allele were found in adult flies. The frequency of the slow allele was 0.448 in flies from Agua Caliente and 0.659 in flies from the Grand Canyon. These frequencies were intermediate to those of the low (Baja California peninsula, Mexico) and high (Sonora, Mexico and southern Arizona) frequency Adh-2S populations of D. mojavensis that utilize different species of host cacti.

  12. Neuronal activity in rat barrel cortex underlying texture discrimination.

    PubMed

    von Heimendahl, Moritz; Itskov, Pavel M; Arabzadeh, Ehsan; Diamond, Mathew E

    2007-11-01

    Rats and mice palpate objects with their whiskers to generate tactile sensations. This form of active sensing endows the animals with the capacity for fast and accurate texture discrimination. The present work is aimed at understanding the nature of the underlying cortical signals. We recorded neuronal activity from barrel cortex while rats used their whiskers to discriminate between rough and smooth textures. On whisker contact with either texture, firing rate increased by a factor of two to ten. Average firing rate was significantly higher for rough than for smooth textures, and we therefore propose firing rate as the fundamental coding mechanism. The rat, however, cannot take an average across trials, but must make an immediate decision using the signals generated on each trial. To estimate single-trial signals, we calculated the mutual information between stimulus and firing rate in the time window leading to the rat's observed choice. Activity during the last 75 ms before choice transmitted the most informative signal; in this window, neuronal clusters carried, on average, 0.03 bits of information about the stimulus on trials in which the rat's behavioral response was correct. To understand how cortical activity guides behavior, we examined responses in incorrect trials and found that, in contrast to correct trials, neuronal firing rate was higher for smooth than for rough textures. Analysis of high-speed films suggested that the inappropriate signal on incorrect trials was due, at least in part, to nonoptimal whisker contact. In conclusion, these data suggest that barrel cortex firing rate on each trial leads directly to the animal's judgment of texture.

  13. Surround suppression and sparse coding in visual and barrel cortices

    PubMed Central

    Sachdev, Robert N. S.; Krause, Matthew R.; Mazer, James A.

    2012-01-01

    During natural vision the entire retina is stimulated. Likewise, during natural tactile behaviors, spatially extensive regions of the somatosensory surface are co-activated. The large spatial extent of naturalistic stimulation means that surround suppression, a phenomenon whose neural mechanisms remain a matter of debate, must arise during natural behavior. To identify common neural motifs that might instantiate surround suppression across modalities, we review models of surround suppression and compare the evidence supporting the competing ideas that surround suppression has either cortical or sub-cortical origins in visual and barrel cortex. In the visual system there is general agreement lateral inhibitory mechanisms contribute to surround suppression, but little direct experimental evidence that intracortical inhibition plays a major role. Two intracellular recording studies of V1, one using naturalistic stimuli (Haider et al., 2010), the other sinusoidal gratings (Ozeki et al., 2009), sought to identify the causes of reduced activity in V1 with increasing stimulus size, a hallmark of surround suppression. The former attributed this effect to increased inhibition, the latter to largely balanced withdrawal of excitation and inhibition. In rodent primary somatosensory barrel cortex, multi-whisker responses are generally weaker than single whisker responses, suggesting multi-whisker stimulation engages similar surround suppressive mechanisms. The origins of suppression in S1 remain elusive: studies have implicated brainstem lateral/internuclear interactions and both thalamic and cortical inhibition. Although the anatomical organization and instantiation of surround suppression in the visual and somatosensory systems differ, we consider the idea that one common function of surround suppression, in both modalities, is to remove the statistical redundancies associated with natural stimuli by increasing the sparseness or selectivity of sensory responses. PMID:22783169

  14. Assembly of 5.5-Meter Diameter Developmental Barrel Segments for the Ares I Upper Stage

    NASA Technical Reports Server (NTRS)

    Carter, Robert W.

    2011-01-01

    Full scale assembly welding of Ares I Upper Stage 5.5-Meter diameter cryogenic tank barrel segments has been performed at the Marshall Space Flight Center (MSFC). One full-scale developmental article produced under the Ares 1 Upper Stage project is the Manufacturing Demonstration Article (MDA) Barrel. This presentation will focus on the welded assembly of this barrel section, and associated lessons learned. Among the MDA articles planned on the Ares 1 Program, the Barrel was the first to be completed, primarily because the process of manufacture from piece parts (barrel panels) utilized the most mature friction stir process planned for use on the Ares US program: Conventional fixed pin Friction Stir Welding (FSW). This process is in use on other space launch systems, including the Shuttle s External Tank, the Delta IV common booster core, the Delta II, and the Atlas V rockets. The goals for the MDA Barrel development were several fold: 1) to prove out Marshall Space Flight Center s new Vertical Weld Tool for use in manufacture of cylindrical barrel sections, 2) to serve as a first run for weld qualification to a new weld specification, and 3) to provide a full size cylindrical section for downstream use in precision cleaning and Spray-on Foam Insulation development. The progression leading into the welding of the full size barrel included sub scale panel welding, subscale cylinder welding, a full length confidence weld, and finally, the 3 seamed MDA barrel processing. Lessons learned on this MDA program have been carried forward into the production tooling for the Ares 1 US Program, and in the use of the MSFC VWT in processing other large scale hardware, including two 8.4 meter diameter Shuttle External Tank barrel sections that are currently being used in structural analysis to validate shell buckling models.

  15. The TIM Barrel Architecture Facilitated the Early Evolution of Protein-Mediated Metabolism.

    PubMed

    Goldman, Aaron David; Beatty, Joshua T; Landweber, Laura F

    2016-01-01

    The triosephosphate isomerase (TIM) barrel protein fold is a structurally repetitive architecture that is present in approximately 10% of all enzymes. It is generally assumed that this ubiquity in modern proteomes reflects an essential historical role in early protein-mediated metabolism. Here, we provide quantitative and comparative analyses to support several hypotheses about the early importance of the TIM barrel architecture. An information theoretical analysis of protein structures supports the hypothesis that the TIM barrel architecture could arise more easily by duplication and recombination compared to other mixed α/β structures. We show that TIM barrel enzymes corresponding to the most taxonomically broad superfamilies also have the broadest range of functions, often aided by metal and nucleotide-derived cofactors that are thought to reflect an earlier stage of metabolic evolution. By comparison to other putatively ancient protein architectures, we find that the functional diversity of TIM barrel proteins cannot be explained simply by their antiquity. Instead, the breadth of TIM barrel functions can be explained, in part, by the incorporation of a broad range of cofactors, a trend that does not appear to be shared by proteins in general. These results support the hypothesis that the simple and functionally general TIM barrel architecture may have arisen early in the evolution of protein biosynthesis and provided an ideal scaffold to facilitate the metabolic transition from ribozymes, peptides, and geochemical catalysts to modern protein enzymes.

  16. Organization of myelin in the mouse somatosensory barrel cortex and the effects of sensory deprivation.

    PubMed

    Barrera, Kyrstle; Chu, Philip; Abramowitz, Jason; Steger, Robert; Ramos, Raddy L; Brumberg, Joshua C

    2013-04-01

    In rodents, the barrel cortex is a specialized area within the somatosensory cortex that processes signals from the mystacial whiskers. We investigated the normal development of myelination in the barrel cortex of mice, as well as the effects of sensory deprivation on this pattern. Deprivation was achieved by trimming the whiskers on one side of the face every other day from birth. In control mice, myelin was not present until postnatal day 14 and did not show prominence until postnatal day 30; adult levels of myelination were reached by the end of the second postnatal month. Unbiased stereology was used to estimate axon density in the interbarrel septal region and barrel walls as well as the barrel centers. Myelin was significantly more concentrated in the interbarrel septa/barrel walls than in the barrel centers in both control and sensory-deprived conditions. Sensory deprivation did not impact the onset of myelination but resulted in a significant decrease in myelinated axons in the barrel region and decreased the amount of myelin ensheathing each axon. Visualization of the oligodendrocyte nuclear marker Olig2 revealed a similar pattern of myelin as seen using histochemistry, but with no significant changes in Olig2+ nuclei following sensory deprivation. Consistent with the anatomical results showing less myelination, local field potentials revealed slower rise times following trimming. Our results suggest that myelination develops relatively late and can be influenced by sensory experience.

  17. Structural insight into the biogenesis of β-barrel membrane proteins.

    PubMed

    Noinaj, Nicholas; Kuszak, Adam J; Gumbart, James C; Lukacik, Petra; Chang, Hoshing; Easley, Nicole C; Lithgow, Trevor; Buchanan, Susan K

    2013-09-19

    β-barrel membrane proteins are essential for nutrient import, signalling, motility and survival. In Gram-negative bacteria, the β-barrel assembly machinery (BAM) complex is responsible for the biogenesis of β-barrel membrane proteins, with homologous complexes found in mitochondria and chloroplasts. Here we describe the structure of BamA, the central and essential component of the BAM complex, from two species of bacteria: Neisseria gonorrhoeae and Haemophilus ducreyi. BamA consists of a large periplasmic domain attached to a 16-strand transmembrane β-barrel domain. Three structural features shed light on the mechanism by which BamA catalyses β-barrel assembly. First, the interior cavity is accessible in one BamA structure and conformationally closed in the other. Second, an exterior rim of the β-barrel has a distinctly narrowed hydrophobic surface, locally destabilizing the outer membrane. And third, the β-barrel can undergo lateral opening, suggesting a route from the interior cavity in BamA into the outer membrane.

  18. Prenatal alcohol exposure delays the development of the cortical barrel field in neonatal rats.

    PubMed

    Margret, Cecilia P; Li, Cheng X; Chappell, Tyson D; Elberger, Andrea J; Matta, Shannon G; Waters, Robert S

    2006-06-01

    In-utero alcohol exposure produces sensorimotor developmental abnormalities that often persist into adulthood. The rodent cortical barrel field associated with the representation of the body surface was used as our model system to examine the effect of prenatal alcohol exposure (PAE) on early somatosensory cortical development. In this study, pregnant female rats were intragastrically gavaged daily with high doses of alcohol (6 gm/kg body weight) throughout the first 20 days of pregnancy. Blood alcohol levels were measured in the pregnant dams on gestational days 13 (G13) and G20. The ethanol treated group (EtOH) was compared to the normal control chowfed (CF) group, nutritionally matched pairfed (PF) group, and cross-foster (XF) group. Cortical barrel development was examined in pups across all treatment groups from G25, corresponding to postnatal day 2 (P2), to G32 corresponding to P9. The EtOH and control group pups were weighed, anesthetized, and perfused. Brains were removed and weighed with, and without cerebellum and olfactory bulbs, and neocortex was removed and weighed. Cortices were then flattened, sectioned tangentially, and stained with a metabolic marker, cytochrome oxidase (CO) to reveal the barrel field. Progression of barrel development was distinguished into three categories: (a) absent, (b) cloudy barrel-like pattern, and (c) well-formed barrels with intervening septae. The major findings are: (1) PAE delayed barrel field development by one or more days, (2) the barrel field first appeared as a cloudy pattern that gave way on subsequent days to an adult-like pattern with clearly demarcated intervening septal regions, (3) the barrel field developed differentially in a lateral-to-medial gradient in both alcohol and control groups, (4) PAE delayed birth by one or more days in 53% of the pups, (5) regardless of whether pups were born on G23 (normal expected birth date for non-alcohol controls) or as in the case for the alcohol-delayed pups born as

  19. [The composition and characteristics of the spread of the shot products from a gas-barrel weapon].

    PubMed

    Isakov, V D; Babakhanian, R V; Kuznetsov, Iu D; Sigalov, F A

    1998-01-01

    Chemical composition and diffusion of additional factors of a shot from barrel gun supplied with a standard chemical cartridge are studied. Experimental shots from gas pistols of three designs were made. During shots from gas barrel guns the victim is exposed to additional factors characteristic of both fire arms and gas barrel guns, namely, fragments of plastic cartridge container and pads, magnesium particles, and lacquer powder. The characteristics of the short range zone for gas barrel guns correspond to those of short barrel fire arms.

  20. Dynamically tuned shroud for gun barrel vibration attenuation

    NASA Astrophysics Data System (ADS)

    Littlefield, Andrew G.; Kathe, Eric L.; Durocher, Robert

    2002-06-01

    Modern tank guns, such as the one on the Abrams, are stabilized to allow fire on the move while traversing uneven terrain. The current barrel is short enough that treating as a rigid beam allows engagement of another tank at ranges of over a kilometer. However, as the length of the tube is extended, to meet required muzzle exit velocities, the terrain induced vibrations lead to increased muzzle pointing errors. A method to reduce these vibrations is to use the forward thermal shroud as part of a mass tuned damper. In this case the system under study is an extended length version of the gun currently fielded. This extended length increases its susceptibility to terrain-induced vibrations. The forward thermal shroud has been shortened and additional mass has been added onto its forward collar. This collar is then supported by springs, which are preloaded so that they stay in contact through the full range of the shroud's movement. Varying the stiffness of these springs allows for tuning of the absorber. Different types of springs and attachments have been tried. The current version uses leaf springs and a wedge collar. This system has been modeled and experiments conducted to validate the model.

  1. 15 CFR 241.6 - Classes of barrels for tolerance application.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... FRUITS, VEGETABLES AND OTHER DRY COMMODITIES, AND FOR CRANBERRIES § 241.6 Classes of barrels for... other dry commodities other than cranberries, are hereby divided into two classes as follows: (a)...

  2. 15 CFR 241.6 - Classes of barrels for tolerance application.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... FRUITS, VEGETABLES AND OTHER DRY COMMODITIES, AND FOR CRANBERRIES § 241.6 Classes of barrels for... other dry commodities other than cranberries, are hereby divided into two classes as follows: (a)...

  3. 15 CFR 241.6 - Classes of barrels for tolerance application.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... FRUITS, VEGETABLES AND OTHER DRY COMMODITIES, AND FOR CRANBERRIES § 241.6 Classes of barrels for... other dry commodities other than cranberries, are hereby divided into two classes as follows: (a)...

  4. 15 CFR 241.6 - Classes of barrels for tolerance application.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... FRUITS, VEGETABLES AND OTHER DRY COMMODITIES, AND FOR CRANBERRIES § 241.6 Classes of barrels for... other dry commodities other than cranberries, are hereby divided into two classes as follows: (a)...

  5. 15 CFR 241.6 - Classes of barrels for tolerance application.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... FRUITS, VEGETABLES AND OTHER DRY COMMODITIES, AND FOR CRANBERRIES § 241.6 Classes of barrels for... other dry commodities other than cranberries, are hereby divided into two classes as follows: (a)...

  6. Beta 2-adrenergic receptors are colocalized and coregulated with whisker barrels in rat somatosensory cortex

    SciTech Connect

    Vos, P.; Kaufmann, D.; Hand, P.J.; Wolfe, B.B. )

    1990-07-01

    Autoradiography has been used to visualize independently the subtypes of beta-adrenergic receptors in rat somatosensory cortex. Beta 2-adrenergic receptors, but not beta 1-adrenergic receptors colocalize with whisker barrels in this tissue. Thus, each whisker sends a specific multisynaptic pathway to the somatosensory cortex that can be histochemically visualized and only one subtype of beta-adrenergic receptor is specifically associated with this cortical representation. Additionally, neonatal lesion of any or all of the whisker follicles results in loss of the corresponding barrel(s) as shown by histochemical markers. This loss is paralleled by a similar loss in the organization of beta 2-adrenergic receptors in the somatosensory cortex. Other results indicate that these beta 2-adrenergic receptors are not involved in moment-to-moment signal transmission in this pathway and, additionally, are not involved in a gross way in the development of whisker-barrel array.

  7. External barrel temperature of a small bore olympic rifle and shooting precision.

    PubMed

    Gladyszewska, B; Baranowski, P; Mazurek, W; Wozniak, J; Gladyszewski, G

    2013-03-01

    Investigations on changes in a rifle's barrel temperature during shooting in a rhythm typical for practitioners of Olympic shooting sports are presented. Walther KK300 (cal. 5.6 mm), a typical rifle often used in Olympic competitions, R50 RWS ammunition and a high speed thermographic camera were used in the study. Altair version 5 software was used to process thermal images and a stationary wavelet transform was applied to denoise signals for all the studied points. It was found that the temperature of the rifle barrel does not exceed 0.3°C after one shot whereas the total temperature increase does not exceed 5°C after taking 40 shots and does not affect the position of the hitting point on a target. In fact, contrary to popular belief, the so-called "warming shots" are not done for barrel heating but for cleaning of remnants in the barrel.

  8. A radial map of multi-whisker correlation selectivity in the rat barrel cortex

    PubMed Central

    Estebanez, Luc; Bertherat, Julien; Shulz, Daniel E.; Bourdieu, Laurent; Léger, Jean- François

    2016-01-01

    In the barrel cortex, several features of single-whisker stimuli are organized in functional maps. The barrel cortex also encodes spatio-temporal correlation patterns of multi-whisker inputs, but so far the cortical mapping of neurons tuned to such input statistics is unknown. Here we report that layer 2/3 of the rat barrel cortex contains an additional functional map based on neuronal tuning to correlated versus uncorrelated multi-whisker stimuli: neuron responses to uncorrelated multi-whisker stimulation are strongest above barrel centres, whereas neuron responses to correlated and anti-correlated multi-whisker stimulation peak above the barrel–septal borders, forming rings of multi-whisker synchrony-preferring cells. PMID:27869114

  9. Carbon fiber plates production for the CMS tracker outer barrel detector

    SciTech Connect

    Lanfranco, Giobatta; /Fermilab

    2001-03-01

    The production methods together with the achieved flatness and thickness of the composite support structures of the CMS tracker outer barrel (TOB) detector are presented. Possible areas of improvement in the process and in the materials used are also suggested.

  10. Perilous proximity: Does the Janzen-Connell hypothesis explain the distribution of giant barrel sponges on a Florida coral reef?

    NASA Astrophysics Data System (ADS)

    Deignan, Lindsey K.; Pawlik, Joseph R.

    2015-06-01

    One popular concept used to explain the high biodiversity of some ecosystems is the Janzen-Connell hypothesis, which states that the distribution of conspecifics is controlled by species-specific pathogens or predators that are attracted to adults or to their reproductive output. The distribution of the affected species would then display a distinct pattern, with survivorship increasing at greater distance from the conspecific adult (negative density dependence), leaving a vacant area around the adult where other species can survive. The giant barrel sponge, Xestospongia muta, is an abundant and long-lived sponge on Caribbean coral reefs that is actively grazed by sponge-eating fishes and is susceptible to disease. We tested the Janzen-Connell hypothesis on barrel sponges on Conch Reef, Florida, by examining their distribution as a function of size using spatial point pattern analyses. Clark and Evans tests and a series of Ripley's K function analyses revealed no consistent distribution pattern, with most analyses resulting in a random pattern of sponge distribution. While predation by sponge-eating fishes has recently been discovered to structure sponge communities on reefs across the Caribbean, these top-down effects do not translate to spatial distributions of X. muta that support Janzen-Connell predictions.

  11. Yeast Mitochondria as a Model System to Study the Biogenesis of Bacterial β-Barrel Proteins.

    PubMed

    Ulrich, Thomas; Oberhettinger, Philipp; Autenrieth, Ingo B; Rapaport, Doron

    2015-01-01

    Beta-barrel proteins are found in the outer membrane of Gram-negative bacteria, mitochondria, and chloroplasts. The evolutionary conservation in the biogenesis of these proteins allows mitochondria to assemble bacterial β-barrel proteins in their functional form. In this chapter, we describe exemplarily how the capacity of yeast mitochondria to process the trimeric autotransporter YadA can be used to study the role of bacterial periplasmic chaperones in this process.

  12. Functionally independent columns of rat somatosensory barrel cortex revealed with voltage-sensitive dye imaging.

    PubMed

    Petersen, C C; Sakmann, B

    2001-11-01

    Whisker movement is somatotopically represented in rodent neocortex by electrical activity in clearly defined barrels, which can be visualized in living brain slices. The functional architecture of this part of the cortex can thus be mapped in vitro with respect to its physiological input and compared with its anatomical architecture. The spatial extent of excitation was measured at high temporal resolution by imaging optical signals from voltage-sensitive dye evoked by stimulation of individual barrels in layer 4. The optical signals correlated closely with subthreshold EPSPs recorded simultaneously from excitatory neurons in layer 4 and layer 2/3, respectively. Excitation was initially (<2 msec) limited to the stimulated barrel and subsequently (>3 msec) spread in a columnar manner into layer 2/3 and then subsided in both layers after approximately 50 msec. The lateral extent of the response was limited to the cortical column defined structurally by the barrel in layer 4. Two experimental interventions increased the spread of excitation. First, blocking GABA(A) receptor-mediated synaptic inhibition caused excitation to spread laterally throughout wide regions of layer 2/3 and layer 5 but not into neighboring barrels, suggesting that the local excitatory connections within layer 4 are restricted to single barrels and that inhibitory neurons control spread in supragranular and infragranular layers. Second, NMDA receptor-dependent increase of the spread of excitation was induced by pairing repetitive stimulation of a barrel column with coincident stimulation of layer 2/3 in a neighboring column. Such plasticity in the spatial extent of excitation in a barrel column could underlie changes in cortical map structure induced by alterations of sensory experience.

  13. The serotonin reuptake inhibitor citalopram suppresses activity in the neonatal rat barrel cortex in vivo.

    PubMed

    Akhmetshina, Dinara; Zakharov, Andrei; Vinokurova, Daria; Nasretdinov, Azat; Valeeva, Guzel; Khazipov, Roustem

    2016-06-01

    Inhibition of serotonin uptake, which causes an increase in extracellular serotonin levels, disrupts the development of thalamocortical barrel maps in neonatal rodents. Previous in vitro studies have suggested that the disruptive effect of excessive serotonin on barrel map formation involves a depression at thalamocortical synapses. However, the effects of serotonin uptake inhibitors on the early thalamocortical activity patterns in the developing barrel cortex in vivo remain largely unknown. Here, using extracellular recordings of the local field potentials and multiple unit activity (MUA) we explored the effects of the selective serotonin reuptake inhibitor (SSRI) citalopram (10-20mg/kg, intraperitoneally) on sensory evoked activity in the barrel cortex of neonatal (postnatal days P2-5) rats in vivo. We show that administration of citalopram suppresses the amplitude and prolongs the delay of the sensory evoked potentials, reduces the power and frequency of the early gamma oscillations, and suppresses sensory evoked and spontaneous neuronal firing. In the adolescent P21-29 animals, citalopram affected neither sensory evoked nor spontaneous activity in barrel cortex. We suggest that suppression of the early thalamocortical activity patterns contributes to the disruption of the barrel map development caused by SSRIs and other conditions elevating extracellular serotonin levels.

  14. Cortical damping: analysis of thalamocortical response transformations in rodent barrel cortex.

    PubMed

    Pinto, David J; Hartings, Jed A; Brumberg, Joshua C; Simons, Daniel J

    2003-01-01

    In the whisker-barrel system, layer IV excitatory neurons respond preferentially to high-velocity deflections of their principal whisker, and these responses are inhibited by deflections of adjacent whiskers. Thalamic input neurons are amplitude and velocity sensitive and have larger excitatory and weaker inhibitory receptive fields than cortical neurons. Computational models based on known features of barrel circuitry capture these and other differences between thalamic and cortical neuron response properties. The models' responses are highly sensitive to thalamic firing synchrony, a finding subsequently confirmed in real barrels by in vivo experiments. Here, we use dynamic systems analysis to examine how barrel circuitry attains its sensitivity to input timing, and how this sensitivity explains the transformation of receptive fields between thalamus and cortex. We find that strong inhibition renders the net effect of intracortical connections suppressive or damping, distinguishing it from previous amplifying models of cortical microcircuits. In damping circuits, recurrent excitation enhances response tuning not by amplifying responses to preferred inputs, but by enabling them to better withstand strong inhibitory influences. Dense interconnections among barrel neurons result in considerable response homogeneity. Neurons outside the barrel layer respond more heterogeneously, possibly reflecting diverse networks and multiple transformations within the cortical output layers.

  15. Evolutions of volatile sulfur compounds of Cabernet Sauvignon wines during aging in different oak barrels.

    PubMed

    Ye, Dong-Qing; Zheng, Xiao-Tian; Xu, Xiao-Qing; Wang, Yun-He; Duan, Chang-Qing; Liu, Yan-Lin

    2016-07-01

    The evolution of volatile sulfur compounds (VSCs) in Cabernet Sauvignon wines from seven regions of China during maturation in oak barrels was investigated. The barrels were made of different wood grains (fine and medium) and toasting levels (light and medium). Twelve VSCs were quantified by GC/FPD, with dimethyl sulfide (DMS) and methionol exceeding their sensory thresholds. Most VSCs tended to decline during the aging, while DMS was found to increase. After one year aging, the levels of DMS, 2-methyltetrahy-drothiophen-3-one and sulfur-containing esters were lower in the wines aged in oak barrels than in stainless steel tanks. The wood grain and toasting level of oak barrels significantly influenced the concentration of S-methyl thioacetate and 2-methyltetrahy-drothiophen-3-one. This study reported the evolution of VSCs in wines during oak barrel aging for the first time and evaluated the influence of barrel types, which would provide wine-makers with references in making proposals about wine aging.

  16. Functional diversity of supragranular GABAergic neurons in the barrel cortex

    PubMed Central

    Gentet, Luc J.

    2012-01-01

    Although the neocortex forms a distributed system comprised of several functional areas, its vertical columnar organization is largely conserved across areas and species, suggesting the existence of a canonical neocortical microcircuit. In order to elucidate the principles governing the organization of such a cortical diagram, a detailed understanding of the dynamics binding different types of cortical neurons into a coherent algorithm is essential. Within this complex circuitry, GABAergic interneurons, while forming approximately only 15–20% of all cortical neurons, appear critical in maintaining a dynamic balance between excitation and inhibition. Despite their importance, cortical GABAergic neurons have not been extensively studied in vivo and their precise role in shaping the local microcircuit sensory response still remains to be determined. Their paucity, combined with their molecular, anatomical, and physiological diversity, has made it difficult to even establish a consensual nomenclature. However, recent technological advances in microscopy and mouse genetics have fostered a renewed interest in neocortical interneurons by putting them within “visible” reach of experimenters. The anatomically well-defined whisker-to-barrel pathway of the rodent is particularly amenable to studies attempting to link cortical circuit dynamics to behavior. To each whisker corresponds a discrete cortical unit equivalent to a single column, specialized in the encoding and processing of the sensory information it receives. In this review, we will focus on the functional role that each subtype of supragranular GABAergic neuron embedded within such a single neocortical unit may play in shaping the dynamics of the local circuit during somatosensory integration. PMID:22912602

  17. Comparison Between Malolactic Fermentation Container and Barrel Toasting Effects on Phenolic, Volatile and Sensory Profile of Red Wines.

    PubMed

    González-Centeno, María Reyes; Chira, Kleopatra; Teissedre, Pierre-Louis

    2017-04-01

    Ellagitannin and anthocyanin profiles, woody volatile composition and sensory properties of wines in which malolactic fermentation (MLF) took place in barrels or stainless steel tanks, have been compared after 12 months of barrel ageing. Three different barrel toastings were evaluated. Barrel-fermented wines generally presented 1.2-fold higher total phenolics, whereas tank-fermented wines exhibited 1.1 and 1.2-fold greater total proanthocyanidin and anthocyanin contents, respectively. Concerning ellagitannin composition, barrel toasting effect seemed to be more important than differences due to MLF-container. Certain woody and fruity volatiles varied significantly (p < 0.05) depending on whether MLF occurred in barrels or tanks. Barrel-fermented wines were preferred in mouth, while olfactory preference depended on barrel toasting. This is the first study that evaluates the impact of oak wood during MLF on ellagitannin composition of wine, as well as the barrel toasting effect on wine attributes during ageing when MLF occurred whether in barrels or tanks.

  18. Performance prospects for the CMS electromagnetic calorimeter barrel avalanche photodiodes for LHC phase I and phase II: Radiation hardness and longevity

    NASA Astrophysics Data System (ADS)

    Addesa, F.; Cavallari, F.

    2015-07-01

    The electromagnetic calorimeter of the Compact Muon Solenoid (CMS) experiment at the LHC is a hermetic, fine-grained, homogeneous calorimeter, comprising 75,848 lead tungstate scintillating crystals. Avalanche photodiodes produced by Hamamatsu are used as sensors for the electromagnetic barrel calorimeter. These devices were tested for radiation hardness assuming an integrated luminosity of 500 fb-1, which corresponds to a neutron fluence of 2- 4 ×1013 n /cm2, depending on the detector location. Beginning in 2022, a new phase of the LHC is foreseen to exploit the full potential of the accelerator, which will deliver 3000 fb-1 of integrated luminosity. Irradiation studies up to a fluence of 1.5 ×1014 n /cm2 have been performed to qualify the avalanche photodiodes for radiation hardness. We present measurements of gain, quantum efficiency and noise, and discuss the implications for the CMS electromagnetic barrel calorimeter performance.

  19. Time-course and mechanisms of homeostatic plasticity in layers 2/3 and 5 of the barrel cortex

    PubMed Central

    2017-01-01

    Recent studies have shown that ocular dominance plasticity in layer 2/3 of the visual cortex exhibits a form of homeostatic plasticity that is related to synaptic scaling and depends on TNFα. In this study, we tested whether a similar form of plasticity was present in layer 2/3 of the barrel cortex and, therefore, whether the mechanism was likely to be a general property of cortical neurons. We found that whisker deprivation could induce homeostatic plasticity in layer 2/3 of barrel cortex, but not in a mouse strain lacking synaptic scaling. The time-course of homeostatic plasticity in layer 2/3 was similar to that of L5 regular spiking (RS) neurons (L5RS), but slower than that of L5 intrinsic bursting (IB) neurons (L5IB). In layer 5, the strength of evoked whisker responses and ex vivo miniature excitatory post-synaptic currents (mEPSCs) amplitudes showed an identical time-course for homeostatic plasticity, implying that plasticity at excitatory synapses contacting layer 5 neurons is sufficient to explain the changes in evoked responses. Spontaneous firing rate also showed homeostatic behaviour for L5IB cells, but was absent for L5RS cells over the time-course studied. Spontaneous firing rate homeostasis was found to be independent of evoked response homeostasis suggesting that the two depend on different mechanisms. This article is part of the themed issue ‘Integrating Hebbian and homeostatic plasticity’. PMID:28093546

  20. Aβ42 assembles into specific β-barrel pore-forming oligomers in membrane-mimicking environments

    PubMed Central

    Serra-Batiste, Montserrat; Ninot-Pedrosa, Martí; Bayoumi, Mariam; Gairí, Margarida; Maglia, Giovanni; Carulla, Natàlia

    2016-01-01

    The formation of amyloid-β peptide (Aβ) oligomers at the cellular membrane is considered to be a crucial process underlying neurotoxicity in Alzheimer’s disease (AD). Therefore, it is critical to characterize the oligomers that form within a membrane environment. To contribute to this characterization, we have applied strategies widely used to examine the structure of membrane proteins to study the two major Aβ variants, Aβ40 and Aβ42. Accordingly, various types of detergent micelles were extensively screened to identify one that preserved the properties of Aβ in lipid environments—namely the formation of oligomers that function as pores. Remarkably, under the optimized detergent micelle conditions, Aβ40 and Aβ42 showed different behavior. Aβ40 aggregated into amyloid fibrils, whereas Aβ42 assembled into oligomers that inserted into lipid bilayers as well-defined pores and adopted a specific structure with characteristics of a β-barrel arrangement that we named β-barrel pore-forming Aβ42 oligomers (βPFOsAβ42). Because Aβ42, relative to Aβ40, has a more prominent role in AD, the higher propensity of Aβ42 to form βPFOs constitutes an indication of their relevance in AD. Moreover, because βPFOsAβ42 adopt a specific structure, this property offers an unprecedented opportunity for testing a hypothesis regarding the involvement of βPFOs and, more generally, membrane-associated Aβ oligomers in AD. PMID:27621459

  1. Time-course and mechanisms of homeostatic plasticity in layers 2/3 and 5 of the barrel cortex.

    PubMed

    Glazewski, Stanislaw; Greenhill, Stuart; Fox, Kevin

    2017-03-05

    Recent studies have shown that ocular dominance plasticity in layer 2/3 of the visual cortex exhibits a form of homeostatic plasticity that is related to synaptic scaling and depends on TNFα. In this study, we tested whether a similar form of plasticity was present in layer 2/3 of the barrel cortex and, therefore, whether the mechanism was likely to be a general property of cortical neurons. We found that whisker deprivation could induce homeostatic plasticity in layer 2/3 of barrel cortex, but not in a mouse strain lacking synaptic scaling. The time-course of homeostatic plasticity in layer 2/3 was similar to that of L5 regular spiking (RS) neurons (L5RS), but slower than that of L5 intrinsic bursting (IB) neurons (L5IB). In layer 5, the strength of evoked whisker responses and ex vivo miniature excitatory post-synaptic currents (mEPSCs) amplitudes showed an identical time-course for homeostatic plasticity, implying that plasticity at excitatory synapses contacting layer 5 neurons is sufficient to explain the changes in evoked responses. Spontaneous firing rate also showed homeostatic behaviour for L5IB cells, but was absent for L5RS cells over the time-course studied. Spontaneous firing rate homeostasis was found to be independent of evoked response homeostasis suggesting that the two depend on different mechanisms.This article is part of the themed issue 'Integrating Hebbian and homeostatic plasticity'.

  2. The CMS barrel calorimeter response to particle beams from 2-GeV/c to 350-GeV/c

    SciTech Connect

    Abdullin, S.; Abramov, V.; Acharya, B.; Adam, N.; Adams, M.; Adzic, P.; Akchurin, N.; Akgun, U.; Albayrak, E.; Alemany-Fernandez, R.; Almeida, N.; /Lisbon, LIFEP /Democritos Nucl. Res. Ctr. /Virginia U. /Iowa State U.

    2009-01-01

    The response of the CMS barrel calorimeter (electromagnetic plus hadronic) to hadrons, electrons and muons over a wide momentum range from 2 to 350 GeV/c has been measured. To our knowledge, this is the widest range of momenta in which any calorimeter system has been studied. These tests, carried out at the H2 beam-line at CERN, provide a wealth of information, especially at low energies. The analysis of the differences in calorimeter response to charged pions, kaons, protons and antiprotons and a detailed discussion of the underlying phenomena are presented. We also show techniques that apply corrections to the signals from the considerably different electromagnetic (EB) and hadronic (HB) barrel calorimeters in reconstructing the energies of hadrons. Above 5 GeV/c, these corrections improve the energy resolution of the combined system where the stochastic term equals 84.7 {+-} 1.6% and the constant term is 7.4 {+-} 0.8%. The corrected mean response remains constant within 1.3% rms.

  3. Thalamic adenylyl cyclase 1 is required for barrel formation in the somatosensory cortex.

    PubMed

    Suzuki, A; Lee, L-J; Hayashi, Y; Muglia, L; Itohara, S; Erzurumlu, R S; Iwasato, T

    2015-04-02

    Cyclic AMP signaling is critical for activity-dependent refinement of neuronal circuits. Global disruption of adenylyl cyclase 1 (AC1), the major calcium/calmodulin-stimulated adenylyl cyclase in the brain, impairs formation of whisker-related discrete neural modules (the barrels) in cortical layer 4 in mice. Since AC1 is expressed both in the thalamus and the neocortex, the question of whether pre- or postsynaptic (or both) AC1 plays a role in barrel formation has emerged. Previously, we generated cortex-specific AC1 knockout (Cx-AC1KO) mice and found that these animals develop histologically normal barrels, suggesting a potentially more prominent role for thalamic AC1 in barrel formation. To determine this, we generated three new lines of mice: one in which AC1 is disrupted in nearly half of the thalamic ventrobasal nucleus cells in addition to the cortical excitatory neurons (Cx/pTh-AC1KO mouse), and another in which AC1 is disrupted in the thalamus but not in the cortex or brainstem nuclei of the somatosensory system (Th-AC1KO mouse). Cx/pTh-AC1KO mice show severe deficits in barrel formation. Th-AC1KO mice show even more severe disruption in barrel patterning. In these two lines, single thalamocortical (TC) axon labeling revealed a larger lateral extent of TC axons in layer 4 compared to controls. In the third line, all calcium-stimulated adenylyl cyclases (both AC1 and AC8) are deleted in cortical excitatory neurons. These mice have normal barrels. Taken together, these results indicate that thalamic AC1 plays a major role in patterning and refinement of the mouse TC circuitry.

  4. Long-term sensory deprivation selectively rearranges functional inhibitory circuits in mouse barrel cortex.

    PubMed

    Li, Peijun; Rudolph, Uwe; Huntsman, Molly M

    2009-07-21

    Long-term whisker removal alters the balance of excitation and inhibition in rodent barrel cortex, yet little is known about the contributions of individual cells and synapses in this process. We studied synaptic inhibition in four major types of neurons in live tangential slices that isolate layer 4 in the posteromedial barrel subfield. Voltage-clamp recordings of layer 4 neurons reveal that fast decay of synaptic inhibition requires alpha1-containing GABA(A) receptors. After 7 weeks of deprivation, we found that GABA(A)-receptor-mediated inhibitory postsynaptic currents (IPSCs) in the inhibitory low-threshold-spiking (LTS) cell recorded in deprived barrels exhibited faster decay kinetics and larger amplitudes in whisker-deprived barrels than those in nondeprived barrels in age-matched controls. This was not observed in other cell types. Additionally, IPSCs recorded in LTS cells from deprived barrels show a marked increase in zolpidem sensitivity. To determine if the faster IPSC decay in LTS cells from deprived barrels indicates an increase in alpha1 subunit functionality, we deprived alpha1(H101R) mutant mice with zolpidem-insensitive alpha1-containing GABA(A) receptors. In these mice and matched wild-type controls, IPSC decay kinetics in LTS cells were faster after whisker removal; however, the deprivation-induced sensitivity to zolpidem was reduced in alpha1(H101R) mice. These data illustrate a change of synaptic inhibition in LTS cells via an increase in alpha1-subunit-mediated function. Because alpha1 subunits are commonly associated with circuit-specific plasticity in sensory cortex, this switch in LTS cell synaptic inhibition may signal necessary circuit changes required for plastic adjustments in sensory-deprived cortex.

  5. Barrel time-of-flight detector for the PANDA experiment at FAIR

    NASA Astrophysics Data System (ADS)

    Gruber, L.; Brunner, S. E.; Marton, J.; Orth, H.; Suzuki, K.

    2016-07-01

    The barrel time-of-flight detector for the PANDA experiment at FAIR is foreseen as a Scintillator Tile (SciTil) Hodoscope based on several thousand small plastic scintillator tiles read-out with directly attached Silicon Photomultipliers (SiPMs). The main tasks of the system are an accurate determination of the time origin of particle tracks to avoid event mixing at high collision rates, relative time-of-flight measurements as well as particle identification in the low momentum regime. The main requirements are the use of a minimum material amount and a time resolution of σ < 100 ps. We have performed extensive optimization studies and prototype tests to prove the feasibility of the SciTil design and finalize the R&D phase. In a 2.7 GeV/c proton beam at Forschungszentrum Jülich a time resolution of about 80 ps has been achieved using SiPMs from KETEK and Hamamatsu with an active area of 3 × 3mm2. Employing the Digital Photon Counter from Philips a time resolution of about 30 ps has been reached.

  6. Unusual mode of firearm injury from the recoiled rear end of a gun barrel.

    PubMed

    Agrawal, A; Malla, G; Joshi, S; Kumar, A; Koirala, S

    2008-09-01

    Atypical gunshot wounds are caused by a diverse set of parameters relating to weapons and ammunition. We report a previously-unreported and atypical mode of gunshot wound produced by a detached rear end of the barrel of a gun following accidental gun fire, and discuss the difficulties in the management. A 36-year-old man presented to the emergency department with an alleged history of injury on the forehead with the rear end of a gun barrel following accidental gunfire while cleaning the nozzle. Since the time of injury, the patient was in an altered sensorium and had weakness on the right side of the body. There was minimal but continuous bleeding from the wound, with extrusion of brain matter. Skull radiograph showed that the rear end of the barrel had entered the left frontal bone, with associated depressed fracture of the frontal bone. The patient underwent a bicoronal, bifrontal craniotomy with a T-shaped extension towards the barrel to facilitate the reflection of the scalp flap and to avoid any movement of the barrel as it might further injure the brain. Necrotic brain, dura and bone pieces were removed. The patient was doing well at follow-up except for mild residual motor deficits. This case illustrates that while working with limited facilities, particularly in underdeveloped countries, a careful clinical assessment, interpretation of available images and a judicious operative approach can help to save the patient.

  7. RORβ Induces Barrel-like Neuronal Clusters in the Developing Neocortex

    PubMed Central

    Jabaudon, Denis; J. Shnider, Sara; J. Tischfield, David; J. Galazo, Maria

    2012-01-01

    Neurons in layer IV of the rodent whisker somatosensory cortex are tangentially organized in periodic clusters called barrels, each of which is innervated by thalamocortical axons transmitting sensory information from a single principal whisker, together forming a somatotopic map of the whisker pad. Proper thalamocortical innervation is critical for barrel formation during development, but the molecular mechanisms controlling layer IV neuron clustering are unknown. Here, we investigate the role in this mapping of the nuclear orphan receptor RORβ, which is expressed in neurons in layer IV during corticogenesis. We find that RORβ protein expression specifically increases in the whisker barrel cortex during barrel formation and that in vivo overexpression of RORβ is sufficient to induce periodic barrel-like clustering of cortical neurons. Remarkably, this clustering can be induced as early as E18, prior to innervation by thalamocortical afferents and whisker derived-input. At later developmental stages, these ectopic neuronal clusters are specifically innervated by thalamocortical axons, demonstrated by anterograde labeling from the thalamus and by expression of thalamocortical-specific synaptic markers. Together, these data indicate that RORβ expression levels control cytoarchitectural patterning of neocortical neurons during development, a critical process for the topographical mapping of whisker input onto the cortical surface. PMID:21799210

  8. Angular tuning and velocity sensitivity in different neuron classes within layer 4 of rat barrel cortex.

    PubMed

    Lee, Soo-Hyun; Simons, Daniel J

    2004-01-01

    Local circuitry within layer IV whisker-related barrels is preferentially sensitive to thalamic population firing synchrony, and neurons respond most vigorously to stimuli, such as high-velocity whisker deflections, that evoke it. Field potential recordings suggest that thalamic barreloid neurons having similar angular preferences fire synchronously. To examine whether angular tuning of cortical neurons might also be affected by thalamic firing synchrony, we characterized responses of layer IV units to whisker deflections that varied in angular direction and velocity. Barrel regular-spike units (RSUs) became more tuned for deflection angle with slower whisker movements. Deflection amplitude had no affect. Barrel fast-spike units (FSUs) were poorly tuned for deflection angle, and their responses remained constant with different deflection velocity. The dependence of angular tuning on deflection velocity among barrel RSUs appears to reflect the same underlying response dynamics that determine their velocity sensitivity and receptive field focus. Unexpectedly, septal RSUs and FSUs are largely similar to their barrel counterparts despite available evidence suggesting that they receive different afferent inputs and are embedded within different local circuits.

  9. Adaptation to sensory stimulation in the Rat Barrel Cortex

    NASA Astrophysics Data System (ADS)

    Heiss, Jaime

    Sustained stimulation of sensory organs results in adaptation of the neuronal response along the sensory pathway. Whether or not cortical adaptation affects equally excitatory and inhibitory inputs is poorly understood. This question was examined using patch recordings of neurons in the barrel cortex of anesthetized rats while repetitively stimulating the principal whisker. After characterizing the excitation and inhibition evoked either by single or double whisker deflection or by different stimulation strengths, it was found that inhibition, unlike excitation, sums linearly and adapts more, causing the balance between these inputs to shift towards excitation. A comparison of the latency of thalamic firing and evoked synaptic inputs in the cortex strongly suggests that adaptation of inhibition results mostly from depression of inhibitory synapses rather than reduction in the firing of inhibitory cells. A similar change in the balance was reproduced by a simple feedforward model. The differential adaptation of the synaptic inputs that shifts the balance toward excitation may act as a gain mechanism which enhances the subthreshold response during sustained stimulation, despite a reduction in excitation. Natural sensory stimulation rarely arrives in an isolated manner, but in a context of several stimulations, like when a rat sweeps its whisker along a surface with a given texture. It was shown that individual single cells sporadically fail to respond, in a very variable fashion from trial to trial. Whether or not adaptation is correlated among neighboring neurons or is it a private, independent phenomenon was investigated by performing simultaneous recordings. Neighboring neurons presented a highly correlated responsiveness to repetitive stimulation, which strongly varied from trial to trial in a synchronized way. Population averages of a single trial obtained by LFP recordings and VSD imaging differed considerably from the time average but was highly correlated to

  10. Distributed Wireless Monitoring System for Ullage and Temperature in Wine Barrels

    PubMed Central

    Zhang, Wenqi; Skouroumounis, George K.; Monro, Tanya M.; Taylor, Dennis K.

    2015-01-01

    This paper presents a multipurpose and low cost sensor for the simultaneous monitoring of temperature and ullage of wine in barrels in two of the most important stages of winemaking, that being fermentation and maturation. The distributed sensor subsystem is imbedded within the bung of the barrel and runs on battery for a period of at least 12 months and costs around $27 AUD for all parts. In addition, software was designed which allows for the remote transmission and easy visual interpretation of the data for the winemaker. Early warning signals can be sent when the temperature or ullage deviates from a winemakers expectations so remedial action can be taken, such as when topping is required or the movement of the barrels to a cooler cellar location. Such knowledge of a wine’s properties or storage conditions allows for a more precise control of the final wine quality. PMID:26266410

  11. Network mechanisms of spindle-burst oscillations in the neonatal rat barrel cortex in vivo.

    PubMed

    Minlebaev, Marat; Ben-Ari, Yehezkel; Khazipov, Rustem

    2007-01-01

    Early in development, cortical networks generate particular patterns of activity that participate in cortical development. The dominant pattern of electrical activity in the neonatal rat neocortex in vivo is a spatially confined spindle-burst. Here, we studied network mechanisms of generation of spindle-bursts in the barrel cortex of neonatal rats using a superfused cortex preparation in vivo. Both spontaneous and sensory-evoked spindle-bursts were present in the superfused barrel cortex. Pharmacological analysis revealed that spindle-bursts are driven by glutamatergic synapses with a major contribution of AMPA/kainate receptors, but slight participation of NMDA receptors and gap junctions. Although GABAergic synapses contributed minimally to the pacing the rhythm of spindle-burst oscillations, surround GABAergic inhibition appeared to be crucial for their compartmentalization. We propose that local spindle-burst oscillations, driven by glutamatergic synapses and spatially confined by GABAergic synapses, contribute to the development of barrel cortex during the critical period of developmental plasticity.

  12. Beta-Barrel Scaffold of Fluorescent Proteins: Folding, Stability and Role in Chromophore Formation

    PubMed Central

    Stepanenko, Olesya V.; Stepanenko, Olga V.; Kuznetsova, Irina M.; Verkhusha, Vladislav V.; Turoverov, Konstantin K.

    2013-01-01

    This review focuses on the current view of the interaction between the β-barrel scaffold of fluorescent proteins and their unique chromophore located in the internal helix. The chromophore originates from the polypeptide chain and its properties are influenced by the surrounding protein matrix of the β-barrel. On the other hand, it appears that a chromophore tightens the β-barrel scaffold and plays a crucial role in its stability. Furthermore, the presence of a mature chromophore causes hysteresis of protein unfolding and refolding. We survey studies measuring protein unfolding and refolding using traditional methods as well as new approaches, such as mechanical unfolding and reassembly of truncated fluorescent proteins. We also analyze models of fluorescent protein unfolding and refolding obtained through different approaches, and compare the results of protein folding in vitro to co-translational folding of a newly synthesized polypeptide chain. PMID:23351712

  13. HHrep: de novo protein repeat detection and the origin of TIM barrels

    PubMed Central

    Söding, Johannes; Remmert, Michael; Biegert, Andreas

    2006-01-01

    HHrep is a web server for the de novo identification of repeats in protein sequences, which is based on the pairwise comparison of profile hidden Markov models (HMMs). Its main strength is its sensitivity, allowing it to detect highly divergent repeat units in protein sequences whose repeats could as yet only be detected from their structures. Examples include sequences with β-propellor fold, ferredoxin-like fold, double psi barrels or (βα)8 (TIM) barrels. We illustrate this with proteins from four superfamilies of TIM barrels by revealing a clear 4- and 8-fold symmetry, which we detect solely from their sequences. This symmetry might be the trace of an ancient origin through duplication of a βαβα or βα unit. HHrep can be accessed at . PMID:16844977

  14. HHrep: de novo protein repeat detection and the origin of TIM barrels.

    PubMed

    Söding, Johannes; Remmert, Michael; Biegert, Andreas

    2006-07-01

    HHrep is a web server for the de novo identification of repeats in protein sequences, which is based on the pairwise comparison of profile hidden Markov models (HMMs). Its main strength is its sensitivity, allowing it to detect highly divergent repeat units in protein sequences whose repeats could as yet only be detected from their structures. Examples include sequences with beta-propellor fold, ferredoxin-like fold, double psi barrels or (betaalpha)8 (TIM) barrels. We illustrate this with proteins from four superfamilies of TIM barrels by revealing a clear 4- and 8-fold symmetry, which we detect solely from their sequences. This symmetry might be the trace of an ancient origin through duplication of a betaalphabetaalpha or betaalpha unit. HHrep can be accessed at http://hhrep.tuebingen.mpg.de.

  15. [Automatic polishing of dental prostheses. 1. Development of a centrifugal barrel finishing apparatus].

    PubMed

    Tamaki, Y; Miyazaki, T; Aoyama, N; Suzuki, E; Miyaji, T

    1990-09-01

    A centrifugal barrel finishing apparatus with a variable turn table rotational speed (250-1,000 rpm) was newly developed and barrel finishing of Ni-Cr casting plates (10 x 10 x 2 mm) was performed using alumina base chips. When using the sample with a mirror face the amount of polishing and the surface roughness increased and the surface gloss decreased with the increase in rotation speed. A high rotational speed was useful for coarse polishing and low rotational speed was useful for fine polishing. The continuous barrel polishing was trially performed using the sample prepared by the carborundum wheel under variable rotational speed. Automatic polishing to fine polishing could be done using this apparatus.

  16. Lewin estimates 2 billion barrels of US tar sand recoverable at mid $20/bbl

    SciTech Connect

    Not Available

    1986-12-01

    In 1983, Lewin and Associates prepared a report which established that the US tar sands resource amounts to over 60 billion barrels of bitumen in-place. However, no estimate was made of the technically or economically recoverable portion of this resource. More recent work carried out by Lewin for the US Department of Energy presents an appraisal of technically and economically recoverable tar sands. The paper describes the tar sand resource in-place, tar sand recovery models used in the study, engineering cost models, the economics of the steam soak prospect, and the economics of a surface mining prospect. The results of the Lewin study show that 5.7 billion barrels of domestic tar sand are technically recoverable, using cyclic steam injection and surface extractive mining. Of this, 4.9 billion barrels are technically recoverable from surface mining methods, with 0.8 billion recoverable from steam soak applications. 1 figure, 3 tables.

  17. Persistence of biological traces in gun barrels--an approach to an experimental model.

    PubMed

    Courts, Cornelius; Madea, Burkhard; Schyma, Christian

    2012-05-01

    Traces of backspatter in gun barrels after homicidal or suicidal contact shots may be a valuable source of forensic evidence. Yet, a systematic investigation of the persistence and durability of DNA from biological traces in gun barrels is lacking. Our aim was to generate a realistic model to emulate blood and tissue spatters in gun barrels generated by contact gunshots at biological targets and to analyse the persistence and typability of DNA recovered from such stains. Herein, we devise and evaluate three different models for the emulation of backspatter from contact shots: a gelatine-based model with embedded blood bags, a model based on a spongious matrix soaked with blood and covered with a thin plastic membrane and a head model consisting of an acrylic half sphere filled with ballistic gelatine and with blood bags attached to the sphere under a 3-mm silicone layer. The sampling procedure for all three models: a first shot was fired with several types of guns at each model construction and subsequently a second shot was fired at a backstop. Blood samples were collected after each shot by probing the inner surface of the front and rear end of the respective gun barrel with a sterile swab. DNA was then extracted and quantified and up to 20 different short tandem repeat (STR) systems were amplified to generate DNA profiles. Although DNA quantity and STR typing results were heterogenous between the models, all models succeeded in delivering full STR profiles even after more than one shot. We conclude that biological traces in gun barrels are robust and accessible to forensic analysis and that systematic examination of the inside of gun barrels may be advisable for forensic casework.

  18. Quantitative/Statistical Approach to Bullet-to-Firearm Identification with Consecutively Manufactured Barrels

    SciTech Connect

    Peter Striupaitis; R.E. Gaensslen

    2005-01-30

    Efforts to use objective image comparison and bullet scanning technologies to distinguish bullets from consecutively manufactured handgun barrels from two manufacturers gave mixed results. The ability of a technology to reliably distinguish between matching and non-matching bullets, where the non-matching bullets were as close in pattern to the matching ones as is probably possible, would provide evidence that the distinctions could be made ''objectively'', and independently of human eyes. That evidence is identical or very close to what seems to be needed to satisfy Daubert standards. It is fair to say that the FTI IBIS image comparison technology correctly distinguished between all the Springfield barrel bullets, and between most but not all of the HiPoint barrel bullets. In the HiPoint cases that were not distinguished 100% of the time, they would he distinguished correctly at least 83% of the time. These results, although obviously limited to the materials used in the comparisons, provide strong evidence that barrel-to-bullet matching is objectively reliable. The results with SciClops were less compelling. The results do not mean that bullet-to-barrel matching is not objectively reliable--rather, they mean that this version of the particular technology could not quite distinguish between these extremely similar yet different bullets as well as the image comparison technology did. In a number of cases, the numerical results made the correct distinctions, although they were close to one another. It is hard to say from this data that this technology differs in its ability to make distinctions between the manufacturers, because the results are very similar with both. The human examiner results were as expected. We did not expect any misidentifications, and there were not any. It would have been preferable to have a higher return rate, and thus more comparisons in the overall sample. As noted, the ''consecutively manufactured barrel exercise'' has been done before

  19. 27 CFR 25.160 - Tax adjustment for brewers who produce more than 2,000,000 barrels of beer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... who produce more than 2,000,000 barrels of beer. 25.160 Section 25.160 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY ALCOHOL BEER Tax on Beer Determination of Tax § 25.160 Tax adjustment for brewers who produce more than 2,000,000 barrels of beer....

  20. 27 CFR 25.160 - Tax adjustment for brewers who produce more than 2,000,000 barrels of beer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... who produce more than 2,000,000 barrels of beer. 25.160 Section 25.160 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS BEER Tax on Beer Determination of Tax § 25.160 Tax adjustment for brewers who produce more than 2,000,000 barrels of beer....

  1. 27 CFR 25.160 - Tax adjustment for brewers who produce more than 2,000,000 barrels of beer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... who produce more than 2,000,000 barrels of beer. 25.160 Section 25.160 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY ALCOHOL BEER Tax on Beer Determination of Tax § 25.160 Tax adjustment for brewers who produce more than 2,000,000 barrels of beer....

  2. 27 CFR 25.160 - Tax adjustment for brewers who produce more than 2,000,000 barrels of beer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... who produce more than 2,000,000 barrels of beer. 25.160 Section 25.160 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS BEER Tax on Beer Determination of Tax § 25.160 Tax adjustment for brewers who produce more than 2,000,000 barrels of beer....

  3. An improved method for constructing and selectively silanizing double-barreled, neutral liquid-carrier, ion-selective microelectrodes

    PubMed Central

    Deveau, Jason S.T.; Grodzinski, Bernard

    2005-01-01

    We describe an improved, efficient and reliable method for the vapour-phase silanization of multi-barreled, ion-selective microelectrodes of which the silanized barrel(s) are to be filled with neutral liquid ion-exchanger (LIX). The technique employs a metal manifold to exclusively and simultaneously deliver dimethyldichlorosilane to only the ion-selective barrels of several multi-barreled microelectrodes. Compared to previously published methods the technique requires fewer procedural steps, less handling of individual microelectrodes, improved reproducibility of silanization of the selected microelectrode barrels and employs standard borosilicate tubing rather than the less-conventional theta-type glass. The electrodes remain stable for up to 3 weeks after the silanization procedure. The efficacy of a double-barreled electrode containing a proton ionophore in the ion-selective barrel is demonstrated in situ in the leaf apoplasm of pea (Pisum) and sunflower (Helianthus). Individual leaves were penetrated to depth of ~150 μm through the abaxial surface. Microelectrode readings remained stable after multiple impalements without the need for a stabilizing PVC matrix. PMID:16136222

  4. Involvement and necessity of the Cpx regulon in the event of aberrant β-barrel outer membrane protein assembly

    PubMed Central

    Gerken, Henri; Leiser, Owen P.; Bennion, Drew; Misra, Rajeev

    2010-01-01

    Summary The Cpx and σE regulons help maintain outer membrane integrity; the Cpx pathway monitors the biogenesis of cell surface structures, such as pili, while the σE pathway monitors the biogenesis of β-barrel outer membrane proteins (OMPs). In this study we revealed the importance of the Cpx regulon in the event of β-barrel OMP mis-assembly, by utilizing mutants expressing either a defective β-barrel OMP assembly machinery (Bam) or assembly defective β-barrel OMPs. Analysis of specific mRNAs showed that ΔcpxR bam double mutants failed to induce degP expression beyond the wild type level, despite activation of the σE pathway. The synthetic conditional lethal phenotype of ΔcpxR in mutant Bam or β-barrel OMP backgrounds was reversed by wild type DegP expressed from a heterologous plasmid promoter. Consistent with the involvement of the Cpx regulon in the event of aberrant β-barrel OMP assembly, the expression of cpxP, the archetypal member of the cpx regulon, was upregulated in defective Bam backgrounds or in cells expressing a single assembly-defective β-barrel OMP species. Together, these results showed that both the Cpx and σE regulons are required to reduce envelope stress caused by aberrant β-barrel OMP assembly, with the Cpx regulon principally contributing by controlling degP expression. PMID:20487295

  5. 27 CFR 25.160 - Tax adjustment for brewers who produce more than 2,000,000 barrels of beer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... who produce more than 2,000,000 barrels of beer. 25.160 Section 25.160 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS BEER Tax on Beer Determination of Tax § 25.160 Tax adjustment for brewers who produce more than 2,000,000 barrels of beer....

  6. Antifungal properties of Japanese cedar essential oil from waste wood chips made from used sake barrels.

    PubMed

    Takao, Yoshifumi; Kuriyama, Isoko; Yamada, Tasuku; Mizoguchi, Haruhiko; Yoshida, Hiromi; Mizushina, Yoshiyuki

    2012-05-01

    In this study, we prepared essential oil (EO) from waste wood chips made from used sake barrels (USBs) of Japanese cedar (i.e., EO-USB) by steam distillation. We found that EO-USB and three commercially purchased EOs derived from xylem tissue of Japanese woods, such as Japanese cedar (Cryptomeria japonica), Japanese cypress (Chamaecyparis obtusa) and false arborvitae (Thujopsis dolabrata), suppressed fungal growth activity against Trichophyton rubrum, which is the cause of tinea disease. The magnitude of the suppressive effects of the EOs ranked as follows: T. dolabrata > USB = C. japonica > C. obtusa. These EOs also inhibited the activity of DNA polymerase in an extract from T. rubrum mycelia with the following ranking: T. dolabrata > USB = C. japonica > C. obtusa. In addition, 50 µg/ml of EO-USB showed antifungal properties, killing T. rubrum mycelia at 27-42˚C in 20 min. By gas chromatography/mass spectrometry analysis, the main sesquiterpenes in EO-USB were δ-cadinene (25.94%) and epi-cubenol (11.55%), and the composition of EO-USB was approximately the same as that of EO-C. japonica. Three prepared sesquiterpenes, δ-cadinene, epi-cubenol and β-eudesmol, inhibited the fungal growth and DNA polymerase activities of T. rubrum, and epi-cubenol showed the strongest inhibition among the compounds tested. These sesquiterpenes had no inhibitory effects on the activities of other DNA metabolic enzymes, such as DNA topoisomerase II, IMP dehydrogenase, polynucleotide kinase and deoxyribonuclease from T. rubrum. Taken together, these results suggest that EO-USB containing epi-cubenol may be useful for its anti-tinea disease properties, which are based on DNA polymerase inhibition.

  7. Optimizing nanodiscs and bicelles for solution NMR studies of two β-barrel membrane proteins

    PubMed Central

    Kucharska, Iga; Edrington, Thomas C.; Liang, Binyong

    2015-01-01

    Solution NMR spectroscopy has become a robust method to determine structures and explore the dynamics of integral membrane proteins. The vast majority of previous studies on membrane proteins by solution NMR have been conducted in lipid micelles. Contrary to the lipids that form a lipid bilayer in biological membranes, micellar lipids typically contain only a single hydrocarbon chain or two chains that are too short to form a bilayer. Therefore, there is a need to explore alternative more bilayer-like media to mimic the natural environment of membrane proteins. Lipid bicelles and lipid nanodiscs have emerged as two alternative membrane mimetics that are compatible with solution NMR spectroscopy. Here, we have conducted a comprehensive comparison of the physical and spectroscopic behavior of two outer membrane proteins from Pseudomonas aeruginosa, OprG and OprH, in lipid micelles, bicelles, and nanodiscs of five different sizes. Bicelles stabilized with a fraction of negatively charged lipids yielded spectra of almost comparable quality as in the best micellar solutions and the secondary structures were found to be almost indistinguishable in the two environments. Of the five nanodiscs tested, nanodiscs assembled from MSP1D1ΔH5 performed the best with both proteins in terms of sample stability and spectral resolution. Even in these optimal nanodiscs some broad signals from the membrane embedded barrel were severely overlapped with sharp signals from the flexible loops making their assignments difficult. A mutant OprH that had two of the flexible loops truncated yielded very promising spectra for further structural and dynamical analysis in MSP1D1ΔH5 nanodiscs. PMID:25869397

  8. Volatile compounds and sensorial characterisation of red wine aged in cherry, chestnut, false acacia, ash and oak wood barrels.

    PubMed

    Fernández de Simón, B; Martínez, J; Sanz, M; Cadahía, E; Esteruelas, E; Muñoz, A M

    2014-03-15

    The wood-related volatile profile of wines aged in cherry, acacia, ash, chestnut and oak wood barrels was studied by GC-MS, and could be a useful tool to identify the wood specie used. Thus, 2,4-dihydroxybenzaldehyde in wines aged in acacia barrels, and ethyl-2-benzoate in cherry barrels could be used as chemical markers of these wood species, for authenticity purposes. Also, the quantitative differences obtained in the volatile profiles allow a good classification of all wines regarding wood species of barrels, during all aging time, and they contributed with different intensities to aromatic and gustative characteristics of aged wines. Wines aged in oak were the best valuated during all aging time, but the differences were not always significant. The lowest scores were assigned to wines aged in cherry barrels from 6 months of aging, so this wood could be more suitable in short aging times.

  9. Polyphenols in red wine aged in acacia (Robinia pseudoacacia) and oak (Quercus petraea) wood barrels.

    PubMed

    Sanz, Miriam; Fernández de Simón, Brígida; Esteruelas, Enrique; Muñoz, Angel Ma; Cadahía, Estrella; Hernández, Ma Teresa; Estrella, Isabel; Martinez, Juana

    2012-06-30

    Polyphenolic composition of two Syrah wines aged during 6 or 12 months in medium toasting acacia and oak 225L barrels was studied by LC-DAD-ESI/MS. A total of 43 nonanthocyanic phenolic compounds were found in all wines, and other 15 compounds only in the wines from acacia barrels. Thus, the nonanthocyanic phenolic profile could be a useful tool to identify the wines aged in acacia barrels. Among all of them the dihydrorobinetin highlights because of its high levels, but also robinetin, 2,4-dihydroxybenzaldehyde, a tetrahydroxydihydroflavonol, fustin, butin, a trihydroxymethoxydihydroflavonol and 2,4-dihydroxybenzoic acid were detected at appreciable levels in wines during aging in acacia barrels, and could be used as phenolic markers for authenticity purposes. Although longer contact time with acacia wood mean higher concentrations of phenolic markers found in wines, the identification of these wines will also be easy after short aging times due the high levels reached by these compounds, even after only 2 months of aging.

  10. 27 CFR 478.113a - Importation of firearm barrels by nonlicensees.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 3 2013-04-01 2013-04-01 false Importation of firearm barrels by nonlicensees. 478.113a Section 478.113a Alcohol, Tobacco Products, and Firearms BUREAU OF ALCOHOL, TOBACCO, FIREARMS, AND EXPLOSIVES, DEPARTMENT OF JUSTICE FIREARMS AND AMMUNITION COMMERCE...

  11. 27 CFR 478.113a - Importation of firearm barrels by nonlicensees.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 3 2012-04-01 2010-04-01 true Importation of firearm barrels by nonlicensees. 478.113a Section 478.113a Alcohol, Tobacco Products, and Firearms BUREAU OF ALCOHOL, TOBACCO, FIREARMS, AND EXPLOSIVES, DEPARTMENT OF JUSTICE FIREARMS AND AMMUNITION COMMERCE...

  12. 27 CFR 478.113a - Importation of firearm barrels by nonlicensees.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 3 2010-04-01 2010-04-01 false Importation of firearm barrels by nonlicensees. 478.113a Section 478.113a Alcohol, Tobacco Products, and Firearms BUREAU OF ALCOHOL, TOBACCO, FIREARMS, AND EXPLOSIVES, DEPARTMENT OF JUSTICE FIREARMS AND AMMUNITION COMMERCE...

  13. 27 CFR 478.113a - Importation of firearm barrels by nonlicensees.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 3 2011-04-01 2010-04-01 true Importation of firearm barrels by nonlicensees. 478.113a Section 478.113a Alcohol, Tobacco Products, and Firearms BUREAU OF ALCOHOL, TOBACCO, FIREARMS, AND EXPLOSIVES, DEPARTMENT OF JUSTICE FIREARMS AND AMMUNITION COMMERCE...

  14. 27 CFR 478.113a - Importation of firearm barrels by nonlicensees.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 3 2014-04-01 2014-04-01 false Importation of firearm barrels by nonlicensees. 478.113a Section 478.113a Alcohol, Tobacco Products, and Firearms BUREAU OF ALCOHOL, TOBACCO, FIREARMS, AND EXPLOSIVES, DEPARTMENT OF JUSTICE FIREARMS AND AMMUNITION COMMERCE...

  15. Assessment of Residential Rain Barrel Water Quality and Use in Cincinnati, Ohio

    EPA Science Inventory

    The collection, storage, and reuse of rainwater collected in rain barrels from urban rooftop areas assists municipalities in achieving stormwater management objectives and in some areas also serves as an adjunct resource for domestic water supplies. In this study, rainwater reuse...

  16. Determination of Heat Transfer Coefficient in a Gun Barrel from Experimental Data

    DTIC Science & Technology

    1985-01-01

    Barrels, BRL-R- 1740, September 1974. AD #BOOO71L. Mark W. Zemansky , Heat and Thermodynamics, McGraw-Hill Book Company Inc., New York, 1957. 3 Max Jacob...September 1974. AD #BOO17lL. 2. Mark W. Zemansky , Heat and Thermodynamics, McGraw-Hill Book Company Inc., New York, 1957. 3. Max Jacob, Heat Transfer, Vol. 1

  17. 77 FR 37321 - Safety Zone, Barrel Recovery, Lake Superior; Duluth, MN

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-21

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone, Barrel Recovery, Lake Superior; Duluth, MN... in the 1960's in a portion of Lake Superior approximately between Stoney Point and Brighton Beach... munitions waste materials dumped offshore in a portion of Lake Superior approximately 50 years ago....

  18. Metal dust deposition in a shotgun wound associated with barrel modification.

    PubMed

    Williams, Andrew S; Bowes, Matthew J

    2016-03-01

    Contact-range gunshot wounds commonly demonstrate deposition of black soot in and around the wound. Deposition of other visible pigments originating from the firearm has not been specifically described. In the current case, an adult male was found dead adjacent to a shotgun fixed in a vice grip with a modified, shortened barrel. A handheld, powered, metal grinding wheel was nearby. Autopsy revealed an intraoral gunshot wound, including soot deposition in and around the mouth and within the wound track. In addition, there was a peculiar, gray, lustrous film on the lips, gingiva, and anterior teeth. The material was concentrated around the most severe areas of injury in the anterior mouth and easily rubbed off with a cotton swab. It was not visualized in the rest of the mouth and not present in the larynx, or the esophagus. Overall, our opinion is that this unique, gray, lustrous film represents deposition of fine metallic dust that accumulated in the barrel of the shotgun during its modification with the grinding wheel. This type of unique pigment deposition should be recognized by forensic pathologists as possibly being related to the discharge of a firearm with a recently modified barrel or other cause for fine metallic dust accumulation within the barrel. Depending on the circumstances of the case, collection of samples of such metal dust deposits could be indicated for subsequent analysis.

  19. Analysis of Fibular Single Graft and Fibular Double-barrel Graft for Mandibular Reconstruction

    PubMed Central

    Shimizu, Yusuke; Ihara, Jyun; Kishi, Kazuo

    2016-01-01

    Background: High-quality mandibular reconstruction using vascularized free fibular graft is necessary to provide an osseointegrated dental implant and fixed denture. An appropriate crown–implant ratio is needed, and a good match between bones is extremely important. There are no articles describing the analysis and evaluation of both the fibula and mandible in the same patients. Methods: Computed tomography images of both mandible and fibula of 80 patients were selected in a random manner. We measured bone height of the fibula and mandible at specified points and evaluated the difference of bone height between the fibula and mandible using fibular single or double-barrel grafts. Results: The percentage of patients who had a “good” result for a fibular single graft was only 13.8%. There was no significant difference in bone heights when analyzed by gender. Whether patients were dentulous or not had a large influence on the difference between fibular and mandibular bone heights. Most young patients, but only half of older patients, needed fibular double-barrel grafts. Overweight patients with a high body mass index more often needed fibular double-barrel grafts. Conclusions: For mandibular reconstruction using a fibular graft, preoperative analysis of the patient’s profile and proper use of a fibular single or double-barrel graft contribute to minimizing the difference between the height of the grafted fibula and native mandible and are keys to an ideal reconstruction with good cosmetics and function. PMID:27622091

  20. 7 CFR 58.425 - Conveyor for moving and draining block or barrel cheese.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 3 2011-01-01 2011-01-01 false Conveyor for moving and draining block or barrel cheese. 58.425 Section 58.425 Agriculture Regulations of the Department of Agriculture (Continued... and Grading Service 1 Equipment and Utensils § 58.425 Conveyor for moving and draining block or...

  1. 7 CFR 58.425 - Conveyor for moving and draining block or barrel cheese.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Conveyor for moving and draining block or barrel cheese. 58.425 Section 58.425 Agriculture Regulations of the Department of Agriculture (Continued... and Grading Service 1 Equipment and Utensils § 58.425 Conveyor for moving and draining block or...

  2. 7 CFR 58.425 - Conveyor for moving and draining block or barrel cheese.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 3 2014-01-01 2014-01-01 false Conveyor for moving and draining block or barrel cheese. 58.425 Section 58.425 Agriculture Regulations of the Department of Agriculture (Continued... and Grading Service 1 Equipment and Utensils § 58.425 Conveyor for moving and draining block or...

  3. 7 CFR 58.425 - Conveyor for moving and draining block or barrel cheese.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 3 2012-01-01 2012-01-01 false Conveyor for moving and draining block or barrel cheese. 58.425 Section 58.425 Agriculture Regulations of the Department of Agriculture (Continued... and Grading Service 1 Equipment and Utensils § 58.425 Conveyor for moving and draining block or...

  4. 7 CFR 58.425 - Conveyor for moving and draining block or barrel cheese.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 3 2013-01-01 2013-01-01 false Conveyor for moving and draining block or barrel cheese. 58.425 Section 58.425 Agriculture Regulations of the Department of Agriculture (Continued... and Grading Service 1 Equipment and Utensils § 58.425 Conveyor for moving and draining block or...

  5. Evaluation of mRNA Localization Using Double Barrel Scanning Ion Conductance Microscopy.

    PubMed

    Nashimoto, Yuji; Takahashi, Yasufumi; Zhou, Yuanshu; Ito, Hidenori; Ida, Hiroki; Ino, Kosuke; Matsue, Tomokazu; Shiku, Hitoshi

    2016-07-26

    Information regarding spatial mRNA localization in single cells is necessary for a better understanding of cellular functions in tissues. Here, we report a method for evaluating localization of mRNA in single cells using double-barrel scanning ion conductance microscopy (SICM). Two barrels in a nanopipette were filled with aqueous and organic electrolyte solutions and used for SICM and as an electrochemical syringe, respectively. We confirmed that the organic phase barrel could be used to collect cytosol from living cells, which is a minute but sufficient amount to assess cellular status using qPCR analysis. The water phase barrel could be used for SICM to image topography with subcellular resolution, which could be used to determine positions for analyzing mRNA expression. This system was able to evaluate mRNA localization in single cells. After puncturing the cellular membrane in a minimally invasive manner, using SICM imaging as a guide, we collected a small amount cytosol from different positions within a single cell and showed that mRNA expression depends on cellular position. In this study, we show that SICM imaging can be utilized for the analysis of mRNA localization in single cells. In addition, we fully automated the pipet movement in the XYZ-directions during the puncturing processes, making it applicable as a high-throughput system for collecting cytosol and analyzing mRNA localization.

  6. Npas4 Expression in Two Experimental Models of the Barrel Cortex Plasticity

    PubMed Central

    Kaliszewska, Aleksandra; Kossut, Malgorzata

    2015-01-01

    Npas4 has recently been identified as an important factor in brain plasticity, particularly in mechanisms of inhibitory control. Little is known about Npas4 expression in terms of cortical plasticity. In the present study expressions of Npas4 and the archetypal immediate early gene (IEG) c-Fos were investigated in the barrel cortex of mice after sensory deprivation (sparing one row of whiskers for 7 days) or sensory conditioning (pairing stimulation of one row of whiskers with aversive stimulus). Laser microdissection of individual barrel rows allowed for analysis of IEGs expression precisely in deprived and nondeprived barrels (in deprivation study) or stimulated and nonstimulated barrels (in conditioning study). Cortex activation by sensory conditioning was found to upregulate the expression of both Npas4 and c-Fos. Reorganization of cortical circuits triggered by removal of selected rows of whiskers strongly affected c-Fos but not Npas4 expression. We hypothesize that increased inhibitory synaptogenesis observed previously after conditioning may be mediated by Npas4 expression. PMID:25785202

  7. Fabrication of a glucose biosensor based on inserted barrel plating gold electrodes.

    PubMed

    Hsu, Cheng-Teng; Chung, Hsieh-Hsun; Tsai, Dong-Mung; Fang, Mei-Yen; Hsiao, Hung-Chan; Zen, Jyh-Myng

    2009-01-01

    We demonstrate here the application of barrel plating gold electrodes for fabricating a new type of disposable amperometric glucose biosensor. It is prepared by inserting two barrel plating gold electrodes onto an injection molding plastic base followed by immobilizing with a bioreagent layer and membrane on the electrode surface. The primary function of barrel plating is to provide an economical way to electroplate manufactured parts. The manufacture procedure is simple and can increase the fabrication precision for automation in mass production. At the two-electrode system, the detection of glucose is linear up to 800 mg/dL (i.e., 44.5 mM, r(2) > 0.99) in pH 7.4 PBS with a sensitivity of 0.71 microA/mM. Excellent sensor-to-sensor reproducibility shows coefficients of variation of only 0.8-1.4% for the detection of 56.5-561.0 mg/dL glucose. In laboratory trials 176 capillary blood samples with a range of 30-572 mg/dL glucose are used to evaluate the clinical application of the biosensor. A good linear correlation is observed between the measured values of the proposed biosensor and laboratory reference. Error grid analysis verifies that the proposed technique is promising in fabricating biosensor strips on a mass scale. As successfully demonstrated by using whole blood glucose as a model analyte, the fabrication technique can extend into other barrel plating noble metal electrodes for various applications.

  8. 33 CFR 135.103 - Levy and payment of barrel fee on OCS oil.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... OCS oil. 135.103 Section 135.103 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE POLLUTION FINANCIAL RESPONSIBILITY AND COMPENSATION OFFSHORE OIL POLLUTION COMPENSATION FUND Levy of Fees § 135.103 Levy and payment of barrel fee on OCS oil. (a) A fee of $.03...

  9. VARIABLES AFFECTING EMISSIONS OF PCDDS/FS FROM UNCONTROLLED COMBUSTION OF HOUSEHOLD WASTE IN BARRELS

    EPA Science Inventory

    The uncontrolled burning of household waste in barrels has recently been implicated as a major source of airborne emissions of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDDs/Fs). Based on the need to generate a more accurate emission factor for burn ba...

  10. High speed machining of space shuttle external tank liquid hydrogen barrel panel

    NASA Technical Reports Server (NTRS)

    Hankins, J. D.

    1983-01-01

    Actual and projected optimum High Speed Machining data for producing shuttle external tank liquid hydrogen barrel panels of aluminum alloy 2219-T87 are reported. The data included various machining parameters; e.g., spindle speeds, cutting speed, table feed, chip load, metal removal rate, horsepower, cutting efficiency, cutter wear (lack of) and chip removal methods.

  11. EVALUATION OF EMISSIONS FROM THE OPEN BURNING OF HOUSEHOLD WASTES IN BARRELS - VOLUME 2. APPENDICES

    EPA Science Inventory

    The report gives results of a detailed emissions characterization study undertaken to examine, characterize, and quantify emissions from the simulated burning of household waste in barrels. The study evaluated two waste streams: that of an avid recycler, who removed most of the r...

  12. EVALUATION OF EMISSIONS FROM THE OPEN BURNING OF HOUSEHOLD WASTE IN BARRELS - VOLUME 1. TECHNICAL REPORT

    EPA Science Inventory

    The report gives results of a detailed emissions characterization study undertaken to examine, characterize, and quantify emissions from the simulated burning of household waste in barrels. The study evaluated two waste streams: that of an avid recycler, who removed most of the r...

  13. Simulations and Experiments of Hot Forging Design and Evaluation of the Aircraft Landing Gear Barrel Al Alloy Structure

    NASA Astrophysics Data System (ADS)

    Ram Prabhu, T.

    2016-04-01

    In the present study, the hot forging design of a typical landing gear barrel was evolved using finite element simulations and validated with experiments. A DEFORM3D software was used to evolve the forging steps to obtain the sound quality part free of defects with minimum press force requirements. The hot forging trial of a barrel structure was carried out in a 30 MN hydraulic press based on the simulation outputs. The tensile properties of the part were evaluated by taking samples from all three orientations (longitudinal, long transverse, short transverse). The hardness and microstructure of the part were also investigated. To study the soundness of the product, fluorescent penetrant inspection and ultrasonic testing were performed in order to identify any potential surface or internal defects in the part. From experiments, it was found that the part was formed successfully without any forging defects such as under filling, laps, or folds that validated the effectiveness of the process simulation. The tensile properties of the part were well above the specification limit (>10%) and the properties variation with respect to the orientation was less than 2.5%. The part has qualified the surface defects level of Mil Std 1907 Grade C and the internal defects level of AMS 2630 Class A (2 mm FBh). The microstructure shows mean grain length and width of 167 and 66 µm in the longitudinal direction. However, microstructure results revealed that the coarse grain structure was observed on the flat surface near the lug region due to the dead zone formation. An innovative and simple method of milling the surface layer after each pressing operation was applied to solve the problem of the surface coarse grain structure.

  14. A wireline piston core barrel for sampling cohesionless sand and gravel below the water table

    USGS Publications Warehouse

    Zapico, Michael M.; Vales, Samuel; Cherry, John A.

    1987-01-01

    A coring device has been developed to obtain long and minimally disturbed samples of saturated cohesionless sand and gravel. The coring device, which includes a wireline and piston, was developed specifically for use during hollow-stem auger drilling but it also offers possibilities for cable tool and rotary drilling. The core barrel consists of an inner liner made of inexpensive aluminum or plastic tubing, a piston for core recovery, and an exterior steel housing that protects the liner when the core barrel is driven into the aquifer. The core barrel, which is approximately 1.6m (5.6 feet) long, is advanced ahead of the lead auger by hammering at the surface on drill rods that are attached to the core barrel. After the sampler has been driven 1.5m (5 feet), the drill rods are detached and a wireline is used to hoist the core barrel, with the sample contained in the aluminum or plastic liner, to the surface. A vacuum developed by the piston during the coring operation provides good recovery of both the sediment and aquifer fluids contained in the sediment. In the field the sample tubes can be easily split along their length for on-site inspection or they can be capped with the pore water fluids inside and transported to the laboratory. The cores are 5cm (2 inches) in diameter by 1.5m (5 feet) long. Core acquisition to depths of 35m (115 feet), with a recovery greater than 90 percent, has become routine in University of Waterloo aquifer studies. A large diameter (12.7cm [5 inch]) version has also been used successfully. Nearly continuous sample sequences from sand and gravel aquifers have been obtained for studies of sedimentology, hydraulic conductivity, hydrogeochemistry and microbiology.

  15. Consumer demand for green stormwater management technology in an urban setting: The case of Chicago rain barrels

    NASA Astrophysics Data System (ADS)

    Ando, Amy W.; Freitas, Luiz P. C.

    2011-12-01

    Hydrological disruption and water pollution from urbanization can be reduced if households in urban areas adopt decentralized storm water controls. We study a citywide municipal subsidized rain-barrel program in the third biggest city in the United States, Chicago, to explore what factors influence whether households purchase this sort of green storm water management technology in an urban setting. Specifically, we regress census-tract level data on the number of rain barrels adopted in different parts of the city on socioeconomic variables, data on local flood frequency, and features of the housing stock. We find that rain-barrel purchases are not correlated with local levels of flooding, even though city residents were told by program managers that rain barrels could alleviate local flooding. Instead, rain barrels are heavily concentrated in places with high-income attitudinally green populations. We do find more rain barrels were adopted in places close to rain-barrel distribution points and near sites of hydrological information campaigns; thus, policy makers might increase green-technology adoption in areas where they can do the most good by reducing transaction costs and providing education programs to those areas. Finally, our results indicate that owner occupancy is positively correlated with green-technology adoption. Low-rise rental housing may have inefficiently low levels of adoption, such that city managers might want to develop programs to encourage storm water management investments by landlords who do not live in their own properties.

  16. Cobalamin-Independent Methionine Synthase (MetE): A Face-to-Face Double Barrel that Evolved by Gene Duplication

    SciTech Connect

    Pejcha, Robert; Ludwig, Martha L.

    2010-03-08

    Cobalamin-independent methionine synthase (MetE) catalyzes the transfer of a methyl group from methyltetrahydrofolate to L-homocysteine (Hcy) without using an intermediate methyl carrier. Although MetE displays no detectable sequence homology with cobalamin-dependent methionine synthase (MetH), both enzymes require zinc for activation and binding of Hcy. Crystallographic analyses of MetE from T. maritima reveal an unusual dual-barrel structure in which the active site lies between the tops of the two ({beta}{alpha}){sub 8} barrels. The fold of the N-terminal barrel confirms that it has evolved from the C-terminal polypeptide by gene duplication; comparisons of the barrels provide an intriguing example of homologous domain evolution in which binding sites are obliterated. The C-terminal barrel incorporates the zinc ion that binds and activates Hcy. The zinc-binding site in MetE is distinguished from the (Cys){sub 3}Zn site in the related enzymes, MetH and betaine-homocysteine methyltransferase, by its position in the barrel and by the metal ligands, which are histidine, cysteine, glutamate, and cysteine in the resting form of MetE. Hcy associates at the face of the metal opposite glutamate, which moves away from the zinc in the binary E {center_dot} Hcy complex. The folate substrate is not intimately associated with the N-terminal barrel; instead, elements from both barrels contribute binding determinants in a binary complex in which the folate substrate is incorrectly oriented for methyl transfer. Atypical locations of the Hcy and folate sites in the C-terminal barrel presumably permit direct interaction of the substrates in a ternary complex. Structures of the binary substrate complexes imply that rearrangement of folate, perhaps accompanied by domain rearrangement, must occur before formation of a ternary complex that is competent for methyl transfer.

  17. The New APD Based Readout for the Crystal Barrel Calorimeter

    NASA Astrophysics Data System (ADS)

    Urban, M.; Honisch, Ch; Steinacher, M.; CBELSA/TAPS Collaboration

    2015-02-01

    The CBELSA/TAPS experiment at ELSA measures double polarization observables in meson photoproduction off protons and neutrons. To be able to measure purely neutral reactions off polarized neutrons with high efficiency, the main calorimeter has to be integrated into the first level trigger. This requires to exchange the existing PIN photo diode by a new avalanche photo diode (APD) readout. The newly developed readout electronics will provide an energy resolution compatible to the previous set-up and a fast trigger signal down to 10 MeV energy deposit per crystal. After the successful final tests with a 3x3 CsI crystal matrix in Bonn at ELSA and in Mainz at MAMI all front-end electronics were produced in fall 2013. Automated test routines for the front-end electronics were developed and the characterization measurements of all APDs were successfully accomplished in Bonn. The project is supported by the Deutsche Forschungsgemeinschaft (SFB/TR16) and Schweizerischer Nationalfonds.

  18. Correlation of fitness landscapes from three orthologous TIM barrels originates from sequence and structure constraints

    PubMed Central

    Chan, Yvonne H.; Venev, Sergey V.; Zeldovich, Konstantin B.; Matthews, C. Robert

    2017-01-01

    Sequence divergence of orthologous proteins enables adaptation to environmental stresses and promotes evolution of novel functions. Limits on evolution imposed by constraints on sequence and structure were explored using a model TIM barrel protein, indole-3-glycerol phosphate synthase (IGPS). Fitness effects of point mutations in three phylogenetically divergent IGPS proteins during adaptation to temperature stress were probed by auxotrophic complementation of yeast with prokaryotic, thermophilic IGPS. Analysis of beneficial mutations pointed to an unexpected, long-range allosteric pathway towards the active site of the protein. Significant correlations between the fitness landscapes of distant orthologues implicate both sequence and structure as primary forces in defining the TIM barrel fitness landscape and suggest that fitness landscapes can be translocated in sequence space. Exploration of fitness landscapes in the context of a protein fold provides a strategy for elucidating the sequence-structure-fitness relationships in other common motifs. PMID:28262665

  19. Synaptic molecular imaging in spared and deprived columns of mouse barrel cortex with array tomography

    PubMed Central

    Weiler, Nicholas C; Collman, Forrest; Vogelstein, Joshua T; Burns, Randal; Smith, Stephen J

    2014-01-01

    A major question in neuroscience is how diverse subsets of synaptic connections in neural circuits are affected by experience dependent plasticity to form the basis for behavioral learning and memory. Differences in protein expression patterns at individual synapses could constitute a key to understanding both synaptic diversity and the effects of plasticity at different synapse populations. Our approach to this question leverages the immunohistochemical multiplexing capability of array tomography (ATomo) and the columnar organization of mouse barrel cortex to create a dataset comprising high resolution volumetric images of spared and deprived cortical whisker barrels stained for over a dozen synaptic molecules each. These dataset has been made available through the Open Connectome Project for interactive online viewing, and may also be downloaded for offline analysis using web, Matlab, and other interfaces. PMID:25977797

  20. Synaptic molecular imaging in spared and deprived columns of mouse barrel cortex with array tomography.

    PubMed

    Weiler, Nicholas C; Collman, Forrest; Vogelstein, Joshua T; Burns, Randal; Smith, Stephen J

    2014-01-01

    A major question in neuroscience is how diverse subsets of synaptic connections in neural circuits are affected by experience dependent plasticity to form the basis for behavioral learning and memory. Differences in protein expression patterns at individual synapses could constitute a key to understanding both synaptic diversity and the effects of plasticity at different synapse populations. Our approach to this question leverages the immunohistochemical multiplexing capability of array tomography (ATomo) and the columnar organization of mouse barrel cortex to create a dataset comprising high resolution volumetric images of spared and deprived cortical whisker barrels stained for over a dozen synaptic molecules each. These dataset has been made available through the Open Connectome Project for interactive online viewing, and may also be downloaded for offline analysis using web, Matlab, and other interfaces.

  1. Gamma ray scanner systems for nondestructive assay of heterogeneous waste barrels

    SciTech Connect

    Martz, H.E.; Roberson, G.P.; Decman, D.J.; Camp, D.C.; Levai, F.

    1997-08-01

    Traditional gamma measurement errors are related to non-uniform measurement responses associated with unknown radioactive source and matrix material distributions. These errors can be reduced by application of tomographic techniques that measure these distributions. LLNL has developed two tomographic-based waste assay systems. They use external radioactive sources and tomography-protocol to map the attenuation within a waste barrel as a function of mono-energetic gamma-ray energy in waste containers. Passive tomography is used to localize and identify specific radioactive waste contents within the same waste containers. Reconstruction of the passive data via the active images allows internal waste radioactivities in a barrel to be corrected for any overlying heterogeneous materials, thus yielding an absolute assay of the waste radioactivities. Calibration of both systems requires only point source measurements and are independent of matrix materials.

  2. A Barrel IFR Instrumented With Limited Streamer Tubes for BABAR Experiment

    SciTech Connect

    Andreotti, M.; /Ferrara U. /INFN, Ferrara

    2006-11-15

    The new barrel Instrumented Flux Return (IFR) of BABAR detector will be reported here. Limited Streamer Tubes (LSTs) have been chosen to replace the existing RPCs as active elements of the barrel IFR. The layout of the new detector will be discussed: in particular, a cell bigger than the standard one has been used to improve efficiency and reliability. The extruded profile is coated with a resistive layer of graphite having a typical surface resistivity between 0.2 and 0.4 MOhm/square. The tubes are assembled in modules and installed in 12 active layers of each sextant of the IFR detector. R&D studies to choose the final design and Quality Control procedure adopted during the tube production will be briefly discussed. Finally the performances of installed LSTs into 2/3 of IFR after 8 months of operations will be reported.

  3. a Barrel Ifr Instrumented with Limited Streamer Tubes for Babar Experiment

    NASA Astrophysics Data System (ADS)

    Andreotti, Mirco

    2006-04-01

    The new barrel Instrumented Flux Return (IFR) of BABAR detector will be reported here. Limited Streamer Tubes (LSTs) have been chosen to replace the existing RPCs as active elements of the barrel IFR. The layout of the new detector will be discussed: in particular, a cell bigger than the standard one has been used to improve efficiency and reliability. The extruded profile is coated with a resistive layer of graphite having a typical surface resistivity between 0.2 and 0.4 MOhm/square. The tubes are assembled in modules and installed in 12 active layers of each sextant of the IFR detector. R&D studies to choose the final design and Quality Control procedure adopted during the tube production will be briefly discussed. Finally the performances of installed LSTs into 2/3 of IFR after 8 months of operations will be reported.

  4. a Barrel Ifr Instrumented with Limited Streamer Tubes for Babar Experiment

    NASA Astrophysics Data System (ADS)

    Cibinetto, Gianluigi

    The new barrel Instrumented Flux Return (IFR) of BABAR detector will be reported here. Limited Stramer Tubes (LSTs) have been chosen to replace the existing RPCs as active elements of the barrel IFR. The layout of the new detector will be discussed: in particular, a cell bigger than the standard one has been used to improve efficiency and reliability. The extruded profile is coated with a resistive layer of graphite having a typical surface resistivity between 0.2 and 0.4 MOhm/square. The tubes are assembled in modules and installed in 12 active layers of each sextant of the IFR detector. R&D studies which have been done to choose the final design will be discussed, as well as the Quality Control procedure adopted during the tube production to assure high performances of the detector.

  5. Spatiotemporal evolution of excitation and inhibition in the rat barrel cortex investigated with multielectrode arrays.

    PubMed

    Wirth, Corina; Lüscher, Hans-R

    2004-04-01

    We investigated the spatiotemporal evolution of activity in the rat barrel cortex using multielectrode arrays (MEAs). In acute brain slices, field potentials were recorded simultaneously from 60 electrodes with high spatial and temporal resolution. This new technique allowed us to map functionally discrete barrels and to observe the interplay between the excitatory and inhibitory network. The local field potentials (LFPs) were elicited by focal electrical stimulation in layer 4 (L4). Excitation recorded in a single barrel was first confined to the stimulated barrel and subsequently spread in a columnar manner to layer 2/3 (L2/3). This excitation in L4 and lower L2/3 was followed by inhibition curtailing excitation to a short period lasting only approximately 2 ms. In the uppermost layer, a long-lasting (approximately 10 ms), laterally spreading band of excitation remained active. Blockade of GABAA-receptors resulted in a long-lasting and diffuse activation of L4 and lower L2/3 and abolition of activation of the upper L2/3. Thus inhibition not only shaped the spatial-temporal map of excitation in L4 and lower L2/3 but also resulted indirectly in an excitatory action in the superficial layers. Stimulation in L6 revealed a feedforward inhibition to L4 and subsequently an excitatory L6-L4-L6 loop. The complex interplay between excitation and inhibition opens two spatial windows of excitation in the infra- and supragranular layers. They may prepare the L5 pyramidal neuron for associating top-down input from other cortical regions with bottom-up input from the whisker pad to generate behaviorally relevant output.

  6. Altered somatosensory barrel cortex refinement in the developing brain of Mecp2-null mice.

    PubMed

    Moroto, M; Nishimura, A; Morimoto, M; Isoda, K; Morita, T; Yoshida, M; Morioka, S; Tozawa, T; Hasegawa, T; Chiyonobu, T; Yoshimoto, K; Hosoi, H

    2013-11-06

    Rett syndrome (RTT) is a neurodevelopmental disorder caused by mutations in the methyl-CpG binding protein 2 (MeCP2) gene. In previous studies, monoaminergic dysfunctions have been detected in patients with RTT and in a murine model of RTT, the Mecp2-null mouse. Therefore, the pathogenesis of RTT is thought to involve impairments in the monoaminergic systems. However, there have been limited data showing that the impairment of monoamines leads to early symptoms during development. We used histochemistry to study the somatosensory barrel cortex in the B6.129P2(C)-Mecp2(tm1.1Bird) mouse model of RTT. The barrel cortex is widely used to investigate neuronal development and its regulation by various neurotransmitters including 5-HT. 5-HT levels were measured by high performance liquid chromatography with electrochemical detection (HPLC/EC), and serotonin transporter (SERT) and 5-HT1B receptor mRNAs were measured in the somatosensory cortex, thalamus and striatum on postnatal days (P) 10, P20 and P40. Mecp2-null mice (Mecp2-/y) had significantly smaller barrel fields than age-matched wild-type controls (Mecp2+/y) on P10 and P40, but the topographic map was accurately formed. Levels of 5-HT, and SERT and 5-HT1B receptor mRNA expression in the somatosensory cortex did not differ significantly between the Mecp2-null and wild-type mice on P10. However, thalamic 5-HT was reduced in Mecp2-null mice. Our data indicate that a lack of MeCP2 may disturb the refinement of the barrel cortex in the early postnatal period. Our findings suggest that a decrease in thalamic 5-HT might be involved in this phenomenon.

  7. Cofilin1 Controls Transcolumnar Plasticity in Dendritic Spines in Adult Barrel Cortex

    PubMed Central

    Tsubota, Tadashi; Okubo-Suzuki, Reiko; Ohashi, Yohei; Tamura, Keita; Ogata, Koshin; Yaguchi, Masae; Matsuyama, Makoto; Inokuchi, Kaoru; Miyashita, Yasushi

    2015-01-01

    During sensory deprivation, the barrel cortex undergoes expansion of a functional column representing spared inputs (spared column), into the neighboring deprived columns (representing deprived inputs) which are in turn shrunk. As a result, the neurons in a deprived column simultaneously increase and decrease their responses to spared and deprived inputs, respectively. Previous studies revealed that dendritic spines are remodeled during this barrel map plasticity. Because cofilin1, a predominant regulator of actin filament turnover, governs both the expansion and shrinkage of the dendritic spine structure in vitro, it hypothetically regulates both responses in barrel map plasticity. However, this hypothesis remains untested. Using lentiviral vectors, we knocked down cofilin1 locally within layer 2/3 neurons in a deprived column. Cofilin1-knocked-down neurons were optogenetically labeled using channelrhodopsin-2, and electrophysiological recordings were targeted to these knocked-down neurons. We showed that cofilin1 knockdown impaired response increases to spared inputs but preserved response decreases to deprived inputs, indicating that cofilin1 dependency is dissociated in these two types of barrel map plasticity. To explore the structural basis of this dissociation, we then analyzed spine densities on deprived column dendritic branches, which were supposed to receive dense horizontal transcolumnar projections from the spared column. We found that spine number increased in a cofilin1-dependent manner selectively in the distal part of the supragranular layer, where most of the transcolumnar projections existed. Our findings suggest that cofilin1-mediated actin dynamics regulate functional map plasticity in an input-specific manner through the dendritic spine remodeling that occurs in the horizontal transcolumnar circuits. These new mechanistic insights into transcolumnar plasticity in adult rats may have a general significance for understanding reorganization of

  8. Nitrobindin: An Ubiquitous Family of All β-Barrel Heme-proteins.

    PubMed

    De Simone, Giovanna; Ascenzi, Paolo; Polticelli, Fabio

    2016-06-01

    Rhodnius prolixus nitrophorins (Rp-NPs), Arabidopsis thaliana nitrobindin (At-Nb), and Homo sapiens THAP4 (Hs-THAP4) are the unique known proteins that use a β-barrel fold to bind ferric heme, which is devoted to NO transport and/or catalysis. The eight-stranded antiparallel β-barrel Rp-NPs, which represent the only heme-binding lipocalins, are devoted to deliver NO into the blood vessel of the host and to scavenge histamine during blood sucking. Regarding Nbs, crystallographic data suggest the ability of At-Nb and Hs-THAP4 to bind ferric heme; however, no data are available with respect to these functions in the natural host. Here, a bioinformatics investigation based on the amino acid sequences and three-dimensional structures of At-Nb and Hs-THAP4 suggests a conservation of the 10-stranded antiparallel β-barrel Nb structural module in all life kingdoms of the evolutionary ladder. In particular, amino acid residues involved in the heme recognition and in the structure stabilization of the Nb structural module are highly conserved (identity > 29%; homology > 83%). Moreover, molecular models of putative Nbs from different organisms match very well with each other and known three-dimensional structures of Nbs. Furthermore, phylogenetic tree reconstruction indicates that NPs and Nbs group in distinct clades. These data indicate that 10-stranded β-barrel Nbs constitute a new ubiquitous heme protein family spanning from bacteria to Homo sapiens. © 2016 IUBMB Life, 68(6):423-428, 2016.

  9. Particle contamination from Martin Optical Black. [in design of barrel baffle of Infrared Astronomical Satellite

    NASA Technical Reports Server (NTRS)

    Young, P. J.; Noll, R.; Andreozzi, L.; Hope, J.

    1981-01-01

    The design of the barrel baffle of the Infrared Astronomical Satellite (IRAS) Optical Subsystem to minimize production of particulate contamination is described. The configuration of the 50-inch long, 28.5-inch diameter baffle required pop-rivet assembly after coating with Martin Optical Black for stray light suppression. An experiment to determine the contamination produced at assembly led to the modification of the baffle construction to preclude such damage to the coated surfaces.

  10. Reversibility and two state behaviour in the thermal unfolding of oligomeric TIM barrel proteins.

    PubMed

    Romero-Romero, Sergio; Costas, Miguel; Rodríguez-Romero, Adela; Alejandro Fernández-Velasco, D

    2015-08-28

    Temperature is one of the main variables that modulate protein function and stability. Thermodynamic studies of oligomeric proteins, the dominant protein natural form, have been often hampered because irreversible aggregation and/or slow reactions are common. There are no reports on the reversible equilibrium thermal unfolding of proteins composed of (β/α)8 barrel subunits, albeit this "TIM barrel" topology is one of the most abundant and versatile in nature. We studied the eponymous TIM barrel, triosephosphate isomerase (TIM), belonging to five species of different bacterial taxa. All of them were found to be catalytically efficient dimers. The three-dimensional structure of four enzymes was solved at high/medium resolution. Irreversibility and kinetic control were observed in the thermal unfolding of two TIMs, while for the other three the thermal unfolding was found to follow a two-state equilibrium reversible process. Shifts in the global stability curves of these three proteins are related to the organismal temperature range of optimal growth and modulated by variations in maximum stability temperature and in the enthalpy change at that temperature. Reversibility appears to correlate with the low isoelectric point, the absence of a residual structure in the unfolded state, small cavity volume in the native state, low conformational stability and a low melting temperature. Furthermore, the strong coupling between dimer dissociation and monomer unfolding may reduce aggregation and favour reversibility. It is therefore very thought-provoking to find that a common topological ensemble, such as the TIM barrel, can unfold/refold in the Anfinsen way, i.e. without the help of the cellular machinery.

  11. Destiny of a drop on a fiber: from barrel to clamshell and back

    NASA Astrophysics Data System (ADS)

    Eral, Burak; de Ruiter, J.; de Ruiter, R.; Oh, J. M.; Semprebon, C.; Brinkman, M.; Mugele, F.

    2011-11-01

    Drops on cylindrical fibers are a familiar sight, for instance in the form of dew drops on spider webs. They can exist in two competing morphologies, a cylindrically symmetric barrel state completely engulfing the fiber and an asymmetric clamshell state, in which the drop sits on the side of the fiber. Despite their omnipresence and their practical relevance the physical mechanisms governing the stability of the two morphologies remained elusive. Using electrowetting-functionalized fibers we determined of the stability limits of both morphologies as a function of the two relevant control parameters, the contact angle and the liquid volume. While clamshells are found to prevail for large contact angles and small volumes, and barrels prevail for small angles and large volumes, there is also a wide range of intermediate parameter values, for which both morphologies are mechanically stable. Mapping out the energy landscape of the system by numerical minimization of the free energy we find that the barrel state is easily deformed by non-axisymmetric perturbations. From a general perspective, the demonstration of electrowetting-based reversible switching of liquid morphologies on fibers opens up opportunities for designing functional textiles and porous materials. We thank the Chemical Sciences division of the Netherlands Organization for Scientific Research (NWO-CW) for financial support.

  12. Improving the resistance of a eukaryotic β-barrel protein to thermal and chemical perturbations.

    PubMed

    Gessmann, Dennis; Mager, Frauke; Naveed, Hammad; Arnold, Thomas; Weirich, Sara; Linke, Dirk; Liang, Jie; Nussberger, Stephan

    2011-10-14

    β-Barrel membrane proteins have regular structures with extensive hydrogen-bond networks between their transmembrane (TM) β-strands, which stabilize their protein fold. Nevertheless, weakly stable TM regions, which are important for the protein function and interaction with other proteins, exist. Here, we report on the apparent stability of human Tom40A, a member of the "mitochondrial porin family" and main constituent of the mitochondrial protein-conducting channel TOM (translocase of the outer membrane). Using a physical interaction model, TmSIP, for β-barrel membrane proteins, we have identified three unfavorable β-strands in the TM domain of the protein. Substitution of key residues inside these strands with hydrophobic amino acids results in a decreased sensitivity of the protein to chemical and/or thermal denaturation. The apparent melting temperature observed when denatured at a rate of 1 °C per minute is shifted from 73 to 84 °C. Moreover, the sensitivity of the protein to denaturant agents is significantly lowered. Further, we find a reduced tendency for the mutated protein to form dimers. We propose that the identified weakly stable β-strands 1, 2 and 9 of human Tom40A play an important role in quaternary protein-protein interactions within the mammalian TOM machinery. Our results show that the use of empirical energy functions to model the apparent stability of β-barrel membrane proteins may be a useful tool in the field of nanopore bioengineering.

  13. Improving the Resistance of a Eukaryotic β-Barrel Protein to Thermal and Chemical Perturbation

    PubMed Central

    Gessmann, Dennis; Mager, Frauke; Naveed, Hammad; Arnold, Thomas; Weirich, Sara; Linke, Dirk; Liang, Jie; Nussberger, Stephan

    2013-01-01

    Beta-barrel membrane proteins have regular structures with extensive hydrogen bonding networks between their transmembrane (TM) β-strands, which stabilize their protein fold. Nevertheless, weakly stable TM regions exist, which are important for the protein function and interaction with other proteins. Here, we report on the apparent stability of human Tom40A, a member of the ‘mitochondrial porin family’ and main constituent of the mitochondrial protein-conducting channel TOM. Using a physical interaction model TmSIP for β-barrel membrane proteins, we have identified three β-strands unfavorable in the TM domain of the protein. Substitution of key residues inside these strands with hydrophobic amino acids results in a decreased sensitivity of the protein to chemical and/or thermal denaturation. The apparent melting temperature observed when denatured at a rate of one degree per minute, is shifted from 73 to 84 °C. Moreover, the sensitivity of the protein to denaturant agents is significantly lowered. Further, we find a reduced tendency for the mutated protein to form dimers. We propose that the identified weakly stable β-strands 1, 2 and 9 of human Tom40A play an important role in quaternary protein-protein interactions within the mammalian TOM machinery. Our results show that the use of empirical energy functions to model the apparent stability of β-barrel membrane proteins may be a useful tool in the field of nanopore bioengineering. PMID:21835183

  14. A Novel Mitosomal β-Barrel Outer Membrane Protein in Entamoeba

    PubMed Central

    Santos, Herbert J.; Imai, Kenichiro; Makiuchi, Takashi; Tomii, Kentaro; Horton, Paul; Nozawa, Akira; Ibrahim, Mohamed; Tozawa, Yuzuru; Nozaki, Tomoyoshi

    2015-01-01

    Entamoeba possesses a highly divergent mitochondrion-related organelle known as the mitosome. Here, we report the discovery of a novel protein in Entamoeba, which we name Mitosomal β-barrel Outer Membrane Protein of 30 kDa (MBOMP30). Initially identified through in silico analysis, we experimentally confirmed that MBOMP30 is indeed a β-barrel protein. Circular dichroism analysis showed MBOMP30 has a predominant β-sheet structure. Localization to Entamoeba histolytica mitosomes was observed through Percoll-gradient fractionation and immunofluorescence assay. Mitosomal membrane integration was demonstrated by carbonate fractionation, proteinase K digestion, and immunoelectron microscopy. Interestingly, the deletion of the putative β-signal, a sequence believed to guide β-barrel outer membrane protein (BOMP) assembly, did not affect membrane integration, but abolished the formation of a ~240 kDa complex. MBOMP30 represents only the seventh subclass of eukaryotic BOMPs discovered to date and lacks detectable homologs outside Entamoeba, suggesting that it may be unique to Entamoeba mitosomes. PMID:25711150

  15. Effects of sensory deprivation on columnar organization of neuronal circuits in the rat barrel cortex.

    PubMed

    Schierloh, Anja; Eder, Matthias; Zieglgänsberger, Walter; Dodt, Hans-Ulrich

    2004-08-01

    We examined whether sensory deprivation during formation of the cortical circuitry influences the pattern of intracortical single-cell connections in rat barrel cortex. Excitatory postsynaptic potentials (EPSPs) from layer 2/3 (L2/3) pyramidal neurons were recorded in vitro using patch-clamp techniques. In order to evoke EPSPs, presynaptic neurons were stimulated by photolytically applied glutamate, thus generating action potentials. Synaptic connections between the stimulated and the recorded neuron were identified by the occurrence of PSPs following photostimulation. Sensory deprivation changed the pattern of projections from L4 and L2/3 neurons to L2/3 pyramidal cells. In slices of non-deprived rats 86% of the total presynaptic neurons were located in the first and only 10% in the second barrel column. Deprivation changed these values to 67% and 26%, respectively. Therefore, the probability of presynaptic cells projecting to L2/3 neurons was shifted from adjacent to more remote barrel columns. These results indicate that deprivation of sensory input influences the pattern of intracortical connections.

  16. Lateral opening in the intact β-barrel assembly machinery captured by cryo-EM

    PubMed Central

    Iadanza, Matthew G.; Higgins, Anna J.; Schiffrin, Bob; Calabrese, Antonio N.; Brockwell, David J.; Ashcroft, Alison E.; Radford, Sheena E.; Ranson, Neil A.

    2016-01-01

    The β-barrel assembly machinery (BAM) is a ∼203 kDa complex of five proteins (BamA–E), which is essential for viability in E. coli. BAM promotes the folding and insertion of β-barrel proteins into the outer membrane via a poorly understood mechanism. Several current models suggest that BAM functions through a ‘lateral gating' motion of the β-barrel of BamA. Here we present a cryo-EM structure of the BamABCDE complex, at 4.9 Å resolution. The structure is in a laterally open conformation showing that gating is independent of BamB binding. We describe conformational changes throughout the complex and interactions between BamA, B, D and E, and the detergent micelle that suggest communication between BAM and the lipid bilayer. Finally, using an enhanced reconstitution protocol and functional assays, we show that for the outer membrane protein OmpT, efficient folding in vitro requires lateral gating in BAM. PMID:27686148

  17. Orofacial Neuropathic Pain Leads to a Hyporesponsive Barrel Cortex with Enhanced Structural Synaptic Plasticity

    PubMed Central

    Thibault, Karine; Rivière, Sébastien; Lenkei, Zsolt

    2016-01-01

    Chronic pain is a long-lasting debilitating condition that is particularly difficult to treat due to the lack of identified underlying mechanisms. Although several key contributing processes have been described at the level of the spinal cord, very few studies have investigated the supraspinal mechanisms underlying chronic pain. Using a combination of approaches (cortical intrinsic imaging, immunohistochemical and behavioural analysis), our study aimed to decipher the nature of functional and structural changes in a mouse model of orofacial neuropathic pain, focusing on cortical areas involved in various pain components. Our results show that chronic neuropathic orofacial pain is associated with decreased haemodynamic responsiveness to whisker stimulation in the barrel field cortex. This reduced functional activation is likely due to the increased basal neuronal activity (measured indirectly using cFos and phospho-ERK immunoreactivity) observed in several cortical areas, including the contralateral barrel field, motor and cingulate cortices. In the same animals, immunohistochemical analysis of markers for active pre- or postsynaptic elements (Piccolo and phospho-Cofilin, respectively) revealed an increased immunofluorescence in deep cortical layers of the contralateral barrel field, motor and cingulate cortices. These results suggest that long-lasting orofacial neuropathic pain is associated with exacerbated neuronal activity and synaptic plasticity at the cortical level. PMID:27548330

  18. CREB Regulates Experience-Dependent Spine Formation and Enlargement in Mouse Barrel Cortex

    PubMed Central

    Pignataro, Annabella; Borreca, Antonella; Ammassari-Teule, Martine; Middei, Silvia

    2015-01-01

    Experience modifies synaptic connectivity through processes that involve dendritic spine rearrangements in neuronal circuits. Although cAMP response element binding protein (CREB) has a key function in spines changes, its role in activity-dependent rearrangements in brain regions of rodents interacting with the surrounding environment has received little attention so far. Here we studied the effects of vibrissae trimming, a widely used model of sensory deprivation-induced cortical plasticity, on processes associated with dendritic spine rearrangements in the barrel cortex of a transgenic mouse model of CREB downregulation (mCREB mice). We found that sensory deprivation through prolonged whisker trimming leads to an increased number of thin spines in the layer V of related barrel cortex (Contra) in wild type but not mCREB mice. In the barrel field controlling spared whiskers (Ipsi), the same trimming protocol results in a CREB-dependent enlargement of dendritic spines. Last, we demonstrated that CREB regulates structural rearrangements of synapses that associate with dynamic changes of dendritic spines. Our findings suggest that CREB plays a key role in dendritic spine dynamics and synaptic circuits rearrangements that account for new brain connectivity in response to changes in the environment. PMID:26075101

  19. EMISSIONS OF POLYCHLORINATED DIBENZO-P-DIOXINS AND POLYCHLORINATED DIBENZOFURANS FROM THE OPEN BURNING OF HOUSEHOLD WASTE IN BARRELS

    EPA Science Inventory

    Backyard burning of household waste in barrels is a common waste disposal practice for which pollutant emissions have not been well characterized. This study measured the emissions of several pollutants, including polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofura...

  20. Shifts in Developmental Timing, and Not Increased Levels of Experience-Dependent Neuronal Activity, Promote Barrel Expansion in the Primary Somatosensory Cortex of Rats Enucleated at Birth

    PubMed Central

    Fetter-Pruneda, Ingrid; Ibarrarán-Viniegra, Ana Sofía; Martínez-Martínez, Eduardo; Sandoval-Velasco, Marcela; Uribe-Figueroa, Laura; Padilla-Cortés, Patricia; Mercado-Célis, Gabriela; Gutiérrez-Ospina, Gabriel

    2013-01-01

    Birth-enucleated rodents display enlarged representations of whiskers (i.e., barrels of the posteromedial subfield) in the primary somatosensory cortex. Although the historical view maintains that barrel expansion is due to incremental increases in neuronal activity along the trigeminal pathway during postnatal development, recent evidence obtained in experimental models of intramodal plasticity challenges this view. Here, we re-evaluate the role of experience-dependent neuronal activity on barrel expansion in birth-enucleated rats by combining various anatomical methods and sensory deprivation paradigms. We show that barrels in birth-enucleated rats were already enlarged by the end of the first week of life and had levels of metabolic activity comparable to those in control rats at different ages. Dewhiskering after the postnatal period of barrel formation did not prevent barrel expansion in adult, birth-enucleated rats. Further, dark rearing and enucleation after barrel formation did not lead to expanded barrels in adult brains. Because incremental increases of somatosensory experience did not promote barrel expansion in birth-enucleated rats, we explored whether shifts of the developmental timing could better explain barrel expansion during the first week of life. Accordingly, birth-enucleated rats show earlier formation of barrels, accelerated growth of somatosensory thalamocortical afferents, and an earlier H4 deacetylation. Interestingly, when H4 deacetylation was prevented with a histone deacetylases inhibitor (valproic acid), barrel specification timing returned to normal and barrel expansion did not occur. Thus, we provide evidence supporting that shifts in developmental timing modulated through epigenetic mechanisms, and not increased levels of experience dependent neuronal activity, promote barrel expansion in the primary somatosensory cortex of rats enucleated at birth. PMID:23372796

  1. Fabrication and Tests of M240 Machine Gun Barrels Lined with Stellite 25

    DTIC Science & Technology

    2016-04-01

    UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) US Army Research Laboratory ATTN: RDRL-WMM-F Aberdeen Proving Ground, MD 21005...5069 8. PERFORMING ORGANIZATION REPORT NUMBER ARL-TR-7662 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR’S

  2. A barrel-related interneuron in layer 4 of rat somatosensory cortex with a high intrabarrel connectivity.

    PubMed

    Koelbl, Christian; Helmstaedter, Moritz; Lübke, Joachim; Feldmeyer, Dirk

    2015-03-01

    Synaptic connections between identified fast-spiking (FS), parvalbumin (PV)-positive interneurons, and excitatory spiny neurons in layer 4 (L4) of the barrel cortex were investigated using patch-clamp recordings and simultaneous biocytin fillings. Three distinct clusters of FS L4 interneurons were identified based on their axonal morphology relative to the barrel column suggesting that these neurons do not constitute a homogeneous interneuron population. One L4 FS interneuron type had an axonal domain strictly confined to a L4 barrel and was therefore named "barrel-confined inhibitory interneuron" (BIn). BIns established reliable inhibitory synaptic connections with L4 spiny neurons at a high connectivity rate of 67%, of which 69% were reciprocal. Unitary IPSPs at these connections had a mean amplitude of 0.9 ± 0.8 mV with little amplitude variation and weak short-term synaptic depression. We found on average 3.7 ± 1.3 putative inhibitory synaptic contacts that were not restricted to perisomatic areas. In conclusion, we characterized a novel type of barrel cortex interneuron in the major thalamo-recipient layer 4 forming dense synaptic networks with L4 spiny neurons. These networks constitute an efficient and powerful inhibitory feedback system, which may serve to rapidly reset the barrel microcircuitry following sensory activation.

  3. A Barrel-Related Interneuron in Layer 4 of Rat Somatosensory Cortex with a High Intrabarrel Connectivity

    PubMed Central

    Koelbl, Christian; Helmstaedter, Moritz; Lübke, Joachim; Feldmeyer, Dirk

    2015-01-01

    Synaptic connections between identified fast-spiking (FS), parvalbumin (PV)-positive interneurons, and excitatory spiny neurons in layer 4 (L4) of the barrel cortex were investigated using patch-clamp recordings and simultaneous biocytin fillings. Three distinct clusters of FS L4 interneurons were identified based on their axonal morphology relative to the barrel column suggesting that these neurons do not constitute a homogeneous interneuron population. One L4 FS interneuron type had an axonal domain strictly confined to a L4 barrel and was therefore named “barrel-confined inhibitory interneuron” (BIn). BIns established reliable inhibitory synaptic connections with L4 spiny neurons at a high connectivity rate of 67%, of which 69% were reciprocal. Unitary IPSPs at these connections had a mean amplitude of 0.9 ± 0.8 mV with little amplitude variation and weak short-term synaptic depression. We found on average 3.7 ± 1.3 putative inhibitory synaptic contacts that were not restricted to perisomatic areas. In conclusion, we characterized a novel type of barrel cortex interneuron in the major thalamo-recipient layer 4 forming dense synaptic networks with L4 spiny neurons. These networks constitute an efficient and powerful inhibitory feedback system, which may serve to rapidly reset the barrel microcircuitry following sensory activation. PMID:24076498

  4. Volatile compounds in a spanish red wine aged in barrels made of Spanish, French, and American oak wood.

    PubMed

    De Simón, Brígida Fernández; Cadahía, Estrella; Jalocha, Jerzy

    2003-12-17

    A red Rioja wine was aged in barrels made of Spanish oak wood (Quercus robur, Quercus petraea,Quercus pyrenaica, and Quercus faginea) during 21 months. The concentrations of some volatile compounds [syringaldehyde, vanillin, eugenol, maltol, guaiacol, 4-ethylphenol, cis and trans isomers of beta-methyl-gamma-octalactone, 2-furfuraldehyde, 5-methyl-2-furfuraldehyde, 5-(hydroxymethyl)-2-furfuraldehyde, and furfuryl alcohol] were studied in these wines and compared with those of the same wine aged in barrels made from French oak of Q. robur (Limousin, France) and Q. petraea (Allier, France) and American oak of Quercus alba (Missouri). Similar concentrations of these compounds were found in wines aged in Spanish and French oak wood barrels, and significantly different concentrations were found with respect to wines aged in barrels made of American oak wood, indicating a different behavior. Thus, wines with different characteristics were obtained, depending on the kind of wood. Also, the kind of wood had an important influence on sensory characteristics of wine during the aging process. Spanish oak wood from Q. robur, Q. petraea, and Q. pyrenaica can be considered to be suitable for barrel production for quality wines, because a wine aged in barrels made of these Spanish oak woods showed similar and intermediate characteristics to those of the same wine aged in French and American oak woods usually used in cooperage.

  5. Test Operations Procedure (TOP) 04-4-004A Natural Cold Weather Environment Test of Ammunition, Small Arms

    DTIC Science & Technology

    2012-05-30

    smoke, muzzle flash, ice fog, and sound of the test ammunition when fired under natural cold environmental conditions. d. Manpack Mobility. The...barrels Barrels chambered for the specific test ammunition and ported for electronic or crusher type pressure gauges. b. Table 2 presents...a. When firing in temperatures below 29 ºC (-20 ºF), tracer observation may be obscured by the occurrence of ice fog from the muzzle blast. Ice fog

  6. Comparing the performance of IBIS and BulletTRAX-3D technology using bullets fired through 10 consecutively rifled barrels.

    PubMed

    Brinck, Toni B

    2008-05-01

    This study evaluates the abilities of the Integrated Ballistics Identification System (IBIS) and BulletTRAX-3D electronic imaging systems to identify bullets fired by the same weapon in a large database of images. Ten consecutively rifled handgun barrels were test fired to obtain reference sample and known match sample pairs for upload onto both bullet acquisition systems. Both copper-jacketed and lead bullets were uploaded, to account for variations in the manner in which markings are reproduced on the different metal compositions. Ranked correlation lists were examined and evaluated. For copper-jacketed bullet correlations, both IBIS and BulletTRAX-3D identified all reference samples to their known matches within the top 10 positions. For lead bullets, BulletTRAX-3D identified all reference samples to their known match in the top 10 positions while IBIS identified only 30%. For inter composition comparisons, BulletTRAX-3D was more successful than IBIS, identifying 100% of reference samples to their known match in the top 20 for copper-jacketed to lead comparisons and 90% for lead to copper-jacketed comparisons. These results suggest that BulletTRAX-3D is more effective than IBIS in the analysis of a wider range of bullet types and it was also found to produce images of superior quality.

  7. Effect of limited proteolysis in the 8th loop of the barrel and of antibodies on porcine pancreas amylase activity.

    PubMed

    Desseaux, V; Payan, F; Ajandouz, E H; Svensson, B; Haser, R; Marchis-Mouren, G

    1991-11-15

    The porcine pancreatic alpha-amylase is a (beta/alpha)8-barrel protein, containing domains A and B (peptide sequence 1-403) and a distinct C-domain (peptide sequence 404-496). Separation of the terminal C-domain from the A and B domains has been attempted by limited proteolysis in the hinge region. Subtilisin was found to hydrolyse amylase between residues 369 and 370 situated in the loop between the eighth beta-strand and alpha-helix. The cleaved amylase was isolated by chromatofocusing and found to retain about 60% of the activity of the native enzyme, while the isolated fragments were inactive. Antigen binding fragments prepared from polyclonal antibodies to native amylase and the CNBr-fragment P1 (peptide sequence 395-496) respectively, were tested for influence on the enzyme activity. Antibodies directed against P1 had no effect whereas antibodies against the peptide sequence 1-394 and amylase respectively inhibited hydrolysis of substrates having four or more glucose residues but not of shorter oligomaltosides. Crystallographic analysis revealed that changes in the region of residue 369 might affect the conformation of the active site as well as of a second binding site. This site, located on the enzyme surface, is proposed to be required for the hydrolysis of larger substrates.

  8. R&D progress in SRF surface preparation with centrifugal barrel polishing (cbp) for both Nb and Cu

    SciTech Connect

    Palczewski, Ari

    2013-09-01

    Centrifugal Barrel polishing (CBP) is becoming a common R&D tool for SRF cavity preparation around the world. During the CBP process a cylindrically symmetric SRF cavity is filled with relatively cheap and environmentally friendly abrasive and sealed. The cavity is then spun around a cylindrically symmetric axis at high speeds uniformly conditioning the inner surface. This uniformity is especially relevant for SRF application because many times a single manufacturing defects limits cavity?s performance well below it?s theoretical limit. In addition CBP has created surfaces with roughness?s on the order of 10?s of nm which create a unique surface for wet chemistry or thin film deposition. CBP is now being utilized at Jefferson Laboratory, Fermi Laboratory and Cornell University in the US, Deutsches Elektronen-Synchrotron in Germany, Laboratori Nazionali di Legnaro in Italy, and Raja Ramanna Centre for Advanced Technology in India. In this talk we will present current CBP research from each lab including equipment, baseline recipes, cavity removal rates and subsequent cryogenic cavity tests on niobium as well as copper cavities where available.

  9. Rapid plasticity follows whisker pairing in barrel cortex of the awake rat.

    PubMed

    Sellien, Heike; Ebner, Ford F

    2007-02-01

    Synaptic plasticity can be induced easily throughout life in the rodent somatic sensory cortex. Trimming all but two whiskers on one side of an adult rat's face, called 'whisker pairing', causes the active (intact) whiskers to develop a stronger drive on cortical cells in their respective barrel columns, while inactive (trimmed) whisker efficacy is down-regulated. To date, this type of activity-dependent plasticity has been induced by trimming all but two whiskers, letting the rats explore their environment from 1 day to 1 month, after which cortical responses were analyzed physiologically under anesthesia. Such studies have enhanced our understanding of cortical plasticity, but the anesthesia complicates the examination of changes that occur in the first few hours after whisker trimming. Here we assayed the short-term changes that occur in alert, active animals over a period of hours after whisker trimming. The magnitude of barrel cortex evoked responses was measured in response to stimulation of the cut and paired whiskers of rats under several conditions: (a) whisking in air (control), (b) active whisking of an object by the rat, and (c) epochs of passive whisker stimulation to identify the onset of whisker pairing plasticity changes in cortex. The main difference between whisking in air without contact and passive whisker stimulation is that the former condition induces an increased response to stimulation of inactive cut whiskers, while the latter condition increases the responses to the stimulated whiskers. The results support the conclusion that whisker pairing plasticity in barrel cortex occurs within 4 h after whisker trimming in an awake, alert animal.

  10. Quad-barrel multifunctional electrochemical and ion conductance probe for voltammetric analysis and imaging.

    PubMed

    Nadappuram, Binoy Paulose; McKelvey, Kim; Byers, Joshua C; Güell, Aleix G; Colburn, Alex W; Lazenby, Robert A; Unwin, Patrick R

    2015-04-07

    The fabrication and use of a multifunctional electrochemical probe incorporating two independent carbon working electrodes and two electrolyte-filled barrels, equipped with quasi-reference counter electrodes (QRCEs), in the end of a tapered micrometer-scale pipet is described. This "quad-probe" (4-channel probe) was fabricated by depositing carbon pyrolytically into two diagonally opposite barrels of a laser-pulled quartz quadruple-barrelled pipet. After filling the open channels with electrolyte solution, a meniscus forms at the end of the probe and covers the two working electrodes. The two carbon electrodes can be used to drive local electrochemical reactions within the meniscus while a bias between the QRCEs in the electrolyte channels provides an ion conductance signal that is used to control and position the meniscus on a surface of interest. When brought into contact with a surface, localized high resolution amperometric imaging can be achieved with the two carbon working electrodes with a spatial resolution defined by the meniscus contact area. The substrate can be an insulating material or (semi)conductor, but herein, we focus mainly on conducting substrates that can be connected as a third working electrode. Studies using both aqueous and ionic liquid electrolytes in the probe, together with gold and individual single walled carbon nanotube samples, demonstrate the utility of the technique. Substrate generation-dual tip collection measurements are shown to be characterized by high collection efficiencies (approaching 100%). This hybrid configuration of scanning electrochemical microscopy (SECM) and scanning electrochemical cell microscopy (SECCM) should be powerful for future applications in electrode mapping, as well as in studies of insulating materials as demonstrated by transient spot redox-titration measurements at an electrostatically charged Teflon surface and at a pristine calcite surface, where a functionalized probe is used to follow the

  11. Classifying β-Barrel Assembly Substrates by Manipulating Essential Bam Complex Members

    PubMed Central

    Mahoney, Tara F.; Ricci, Dante P.

    2016-01-01

    ABSTRACT The biogenesis of the outer membrane (OM) of Escherichia coli is a conserved and vital process. The assembly of integral β-barrel outer membrane proteins (OMPs), which represent a major component of the OM, depends on periplasmic chaperones and the heteropentameric β-barrel assembly machine (Bam complex) in the OM. However, not all OMPs are affected by null mutations in the same chaperones or nonessential Bam complex members, suggesting there are categories of substrates with divergent requirements for efficient assembly. We have previously demonstrated two classes of substrates, one comprising large, low-abundance, and difficult-to-assemble substrates that are heavily dependent on SurA and also Skp and FkpA, and the other comprising relatively simple and abundant substrates that are not as dependent on SurA but are strongly dependent on BamB for assembly. Here, we describe novel mutations in bamD that lower levels of BamD 10-fold and >25-fold without altering the sequence of the mature protein. We utilized these mutations, as well as a previously characterized mutation that lowers wild-type BamA levels, to reveal a third class of substrates. These mutations preferentially cause a marked decrease in the levels of multimeric proteins. This susceptibility of multimers to lowered quantities of Bam machines in the cell may indicate that multiple Bam complexes are needed to efficiently assemble multimeric proteins into the OM. IMPORTANCE The outer membrane (OM) of Gram-negative bacteria, such as Escherichia coli, serves as a selective permeability barrier that prevents the uptake of toxic molecules and antibiotics. Integral β-barrel proteins (OMPs) are assembled by the β-barrel assembly machine (Bam), components of which are conserved in mitochondria, chloroplasts, and all Gram-negative bacteria, including many clinically relevant pathogenic species. Bam is essential for OM biogenesis and accommodates a diverse array of client proteins; however, a

  12. Design studies for the Phase II upgrade of the CMS Barrel Electromagnetic Calorimeter

    NASA Astrophysics Data System (ADS)

    Bornheim, A.

    2017-03-01

    The High Luminosity LHC (HL-LHC) aims to reach the unprecedented integrated luminosity of 3 ab‑1 with an instantaneous luminosity up to 5 × 1034 cm‑2 s‑1. This poses stringent requirements on the radiation resistance of detector components and on the latency of the trigger system. The barrel region of the CMS Electromagnetic Calorimeter will be able to retain the current lead tungstate crystals and avalanche photo diode detectors which will meet the performance requirements throughout the operational lifetime of the HL-LHC. The new front-end electronics and very front-end system required at high luminosities will be described.

  13. Subintimal Double-Barrel Restenting of an Occluded Primary Stented Superficial Femoral Artery

    PubMed Central

    Lohle, Paul N.M.; Lampmann, Leo E.H.

    2007-01-01

    In-stent re-stenosis is a frequent complication of endovascular stents, especially in the superficial femoral artery (SFA). Endovascular re-intervention of in- or peri-stent occlusive disease consists of recanilization through the occluded stent. In our case report, we describe the endovascular treatment of a previously placed stent in the SFA. We unintentionally passed the affected stent subintimally, in a double barrel fashion next to the first stent. The procedure was without any complications and with a successfull angiographic result. At one year follow-up the patient still has no complaints and the stent is still patent. PMID:17410397

  14. Barrel-Clamshell analog in the capillary bridges between two solid spheres

    NASA Astrophysics Data System (ADS)

    Bird, James; Farmer, Timothy

    2014-11-01

    Sessile drops on a wire are known to adopt one of two topological configurations, referred to as a barrel or a clamshell, depending on the volume and contact angle. Here we report on an analogous topological transition for the capillary bridge between two contacting solid spheres. We characterize the transition by numerically computing the bridge shapes that minimize surface energy for a variety of contact angles and volumes. Finally, we are able to develop an exact solution to the non-axisymmetric bridge shapes by relying on symmetries of the geometry.

  15. High precision, low disturbance calibration system for the CMS Barrel Electromagnetic Calorimeter High Voltage apparatus

    NASA Astrophysics Data System (ADS)

    Fasanella, G.

    2017-01-01

    The CMS Electromagnetic Calorimeter utilizes scintillation lead tungstate crystals, with avalanche photodiodes (APD) as photo-detectors in the barrel part. 1224 HV channels bias groups of 50 APD pairs, each at a voltage of about 380 V. The APD gain dependence on the voltage is 3%/V. A stability of better than 60 mV is needed to have negligible impact on the calorimeter energy resolution. Until 2015 manual calibrations were performed yearly. A new calibration system was deployed recently, which satisfies the requirement of low disturbance and high precision. The system is discussed in detail and first operational experience is presented.

  16. Precise mapping of the magnetic field in the CMS barrel yoke using cosmic rays

    SciTech Connect

    Chatrchyan, S.; et al.,

    2010-03-01

    The CMS detector is designed around a large 4 T superconducting solenoid, enclosed in a 12000-tonne steel return yoke. A detailed map of the magnetic field is required for the accurate simulation and reconstruction of physics events in the CMS detector, not only in the inner tracking region inside the solenoid but also in the large and complex structure of the steel yoke, which is instrumented with muon chambers. Using a large sample of cosmic muon events collected by CMS in 2008, the field in the steel of the barrel yoke has been determined with a precision of 3 to 8% depending on the location.

  17. Map transfer from the thalamus to the neocortex: inputs from the barrel field.

    PubMed

    Lokmane, Ludmilla; Garel, Sonia

    2014-11-01

    Sensory perception relies on the formation of stereotyped maps inside the brain. This feature is particularly well illustrated in the mammalian neocortex, which is subdivided into distinct cortical sensory areas that comprise topological maps, such as the somatosensory homunculus in humans or the barrel field of the large whiskers in rodents. How somatosensory maps are formed and relayed into the neocortex remain essential questions in developmental neuroscience. Here, we will present our current knowledge on whisker map transfer in the mouse model, with the goal of linking embryonic and postnatal studies into a comprehensive framework.

  18. Endocannabinoid-Dependent Long-Term Potentiation of Synaptic Transmission at Rat Barrel Cortex.

    PubMed

    Maglio, Laura Eva; Noriega-Prieto, José Antonio; Maraver, Maria Jesús; Fernández de Sevilla, David

    2017-03-01

    Brain-derived neurotrophic factor (BDNF) plays a critical role in modulating plasticity in sensory cortices. Indeed, a BDNF-dependent long-term potentiation (LTP) at distal basal excitatory synapses of Layer 5 pyramidal neurons (L5PNs) has been demonstrated in disinhibited rat barrel cortex slices. Although it is well established that this LTP requires the pairing of excitatory postsynaptic potentials (PSPs) with Ca2+ spikes, its induction when synaptic inhibition is working remains unexplored. Here we show that low-frequency stimulation at basal dendrites of L5PNs is able to trigger a PSP followed by an action potential (AP) and a slow depolarization (termed PSP-Ca2+ response) in thalamocortical slices without blocking synaptic inhibition. We demonstrate that AP barrage-mediated release of endocannabinoids (eCBs) from the recorded L5PNs induces PSP-Ca2+ response facilitation and BDNF-dependent LTP. Indeed, this LTP requires the type 1 cannabinoid receptors activation, is prevented by postsynaptic intracellular 1,2-bis(2-aminophenoxy) ethane-N,N,N,N'-tetraacetic acid (BAPTA) or the anandamide membrane transporter inhibitor AM404, and only occurs in L5PNs neurons showing depolarization-induced suppression of inhibition. Additionally, electrical stimulation at the posteromedial thalamic nucleus induced similar response and LTP. These results reveal a novel form of eCB-dependent LTP at L5PNs that could be relevant in the processing of sensory information in the barrel cortex.

  19. Revisiting the oligomerization mechanism of Vibrio cholerae cytolysin, a beta-barrel pore-forming toxin.

    PubMed

    Rai, Anand Kumar; Chattopadhyay, Kausik

    2016-06-03

    Vibrio cholerae cytolysin (VCC) is a membrane-damaging beta-barrel pore-forming toxin (beta-PFT). VCC causes permeabilization of the target membranes by forming transmembrane oligomeric beta-barrel pores. Oligomerization is a key step in the mode of action of any beta-PFT, including that of VCC. Earlier studies have identified some of the key residues in VCC that are directly involved in the generation of the inter-protomer contacts, thus playing critical roles in the oligomerization of the membrane-bound toxin. Analysis of the VCC oligomeric pore structure reveals a potential hydrogen-bond network that appears to connect the sidechain of an asparagine residue (Asn582; located within an inter-domain linker sequence) from one protomer to the backbone CO- and NH-groups of the neighbouring protomer, indirectly through water molecules at most of the inter-protomer interfaces. In the present study, we show that the mutation of Asn582Ala affects the oligomerization and the pore-forming activity of VCC in the membrane lipid bilayer of the synthetic lipid vesicles, while the replacement of Asn582Gln results into the restoration of the oligomeric pore-forming ability of the toxin. Using a number of truncated variants of VCC, having deletion in the C-terminal region of the toxin starting from the Asn582 residue or beyond, we also show that the presence of Asn582 is critically required for the oligomerization of the truncated form of the protein.

  20. Structural (betaalpha)8 TIM barrel model of 3-hydroxy-3-methylglutaryl-coenzyme A lyase.

    PubMed

    Casals, Núria; Gómez-Puertas, Paulino; Pié, Juan; Mir, Cecilia; Roca, Ramón; Puisac, Beatriz; Aledo, Rosa; Clotet, Josep; Menao, Sebastián; Serra, Dolors; Asins, Guillermina; Till, Jacqueline; Elias-Jones, Alun C; Cresto, Juan C; Chamoles, Nestor A; Abdenur, Jose E; Mayatepek, Ertan; Besley, Guy; Valencia, Alfonso; Hegardt, Fausto G

    2003-08-01

    This study describes three novel homozygous missense mutations (S75R, S201Y, and D204N) in the 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) lyase gene, which caused 3-hydroxy-3-methylglutaric aciduria in patients from Germany, England, and Argentina. Expression studies in Escherichia coli show that S75R and S201Y substitutions completely abolished the HMG-CoA lyase activity, whereas D204N reduced catalytic efficiency to 6.6% of the wild type. We also propose a three-dimensional model for human HMG-CoA lyase containing a (betaalpha)8 (TIM) barrel structure. The model is supported by the similarity with analogous TIM barrel structures of functionally related proteins, by the localization of catalytic amino acids at the active site, and by the coincidence between the shape of the substrate (HMG-CoA) and the predicted inner cavity. The three novel mutations explain the lack of HMG-CoA lyase activity on the basis of the proposed structure: in S75R and S201Y because the new amino acid residues occlude the substrate cavity, and in D204N because the mutation alters the electrochemical environment of the active site. We also report the localization of all missense mutations reported to date and show that these mutations are located in the beta-sheets around the substrate cavity.

  1. Morphology and physiology of excitatory neurons in layer 6b of the somatosensory rat barrel cortex.

    PubMed

    Marx, Manuel; Feldmeyer, Dirk

    2013-12-01

    Neocortical lamina 6B (L6B) is a largely unexplored layer with a very heterogeneous cellular composition. To date, only little is known about L6B neurons on a systematic and quantitative basis. We investigated the morphological and electrophysiological properties of excitatory L6B neurons in the rat somatosensory barrel cortex using whole-cell patch-clamp recordings and simultaneous biocytin fillings. Subsequent histological processing and computer-assisted 3D reconstructions provided the basis for a classification of excitatory L6B neurons according to their structural and functional characteristics. Three distinct clusters of excitatory L6B neurons were identified: (C1) pyramidal neurons with an apical dendrite pointing towards the pial surface, (C2) neurons with a prominent, "apical"-like dendrite not oriented towards the pia, and (C3) multipolar spiny neurons without any preferential dendritic orientation. The second group could be further subdivided into three categories termed inverted, "tangentially" oriented and "horizontally" oriented neurons. Furthermore, based on the axonal domain two subcategories of L6B pyramidal cells were identified that had either a more barrel-column confined or an extended axonal field. The classification of excitatory L6B neurons provided here may serve as a basis for future studies on the structure, function, and synaptic connectivity of L6B neurons.

  2. Changes in the sotolon content of dry white wines during barrel and bottle aging.

    PubMed

    Lavigne, Valérie; Pons, Alexandre; Darriet, Philippe; Dubourdieu, Denis

    2008-04-23

    GC-MS in electron ionization mode (EI) was used as a simple, sensitive method for assaying sotolon [4,5-dimethyl-3-hydroxy-2(5) H-furanone] in various dry white wines. The impact of barrel-aging conditions, that is, whether yeast lees were present or not, on the formation of sotolon in dry white wines was then studied. The sotolon content was highest in dry white wines aged in new barrels without lees, often exceeding the perception threshold (8 microg/L). These results demonstrated that yeast lees were capable of minimizing the formation of sotolon in dry white wines during aging. The sotolon and oxygen contents of several bottle of the same white wine were also compared 7 years after bottling. At the range of dissolved oxygen concentrations generally measured, between 5 and 100 microg/L, the sotolon content remained below its perception threshold in wine. The perception threshold was exceeded only in wines with oxygen concentrations above 500 microg/L. The presence of dissolved oxygen in the wine samples analyzed also resulted in a decrease in their free sulfur dioxide content.

  3. Evolution of outer membrane beta-barrels from an ancestral beta beta hairpin.

    PubMed

    Remmert, M; Biegert, A; Linke, D; Lupas, A N; Söding, J

    2010-06-01

    Outer membrane beta-barrels (OMBBs) are the major class of outer membrane proteins from Gram-negative bacteria, mitochondria, and plastids. Their transmembrane domains consist of 8-24 beta-strands forming a closed, barrel-shaped beta-sheet around a central pore. Despite their obvious structural regularity, evidence for an origin by duplication or for a common ancestry has not been found. We use three complementary approaches to show that all OMBBs from Gram-negative bacteria evolved from a single, ancestral beta beta hairpin. First, we link almost all families of known single-chain bacterial OMBBs with each other through transitive profile searches. Second, we identify a clear repeat signature in the sequences of many OMBBs in which the repeating sequence unit coincides with the structural beta beta hairpin repeat. Third, we show that the observed sequence similarity between OMBB hairpins cannot be explained by structural or membrane constraints on their sequences. The third approach addresses a longstanding problem in protein evolution: how to distinguish between a very remotely homologous relationship and the opposing scenario of "sequence convergence." The origin of a diverse group of proteins from a single hairpin module supports the hypothesis that, around the time of transition from the RNA to the protein world, proteins arose by amplification and recombination of short peptide modules that had previously evolved as cofactors of RNAs.

  4. Ground and satellite EMIC wave observations in conjunction with BARREL electron precipitation

    NASA Astrophysics Data System (ADS)

    Weaver, C.; Lessard, M.; Engebretson, M. J.; Millan, R. M.; Halford, A.; Horne, R. B.; Singer, H. J.; Green, J. C.

    2013-12-01

    Ground-based and satellite observations of electromagnetic ion-cyclotron (EMIC) waves are presented in conjunction with electron precipitation detected by high altitude balloons from the Balloon Array for RBSP Relativistic Electron Losses (BARREL) campaign. On 17 Jan 2013, a high density solar wind compressed the magnetosphere and four satellites (GOES 13 & 15, Van Allen Probes A & B) as well as several ground stations (Dawson City, Canada and Halley, Antarctica) detected simultaneous EMIC waves across the night sector for about 2.5 hours during the compression (0130 - 0400 UT). The satellites and ground stations cover approximately 10 hours of magnetic local time and four L-shells, suggesting the generation region(s) covers the same extended area. At the strongest point of the compression (around 0300 UT with proton density 50 n/cc, flow pressure 20 nPa, SYM/H 50 nT) BARREL balloon 1G, which magnetically mapped close to GOES 13, detected relativistic electron precipitation concurrently with enhanced EMIC wave activity on GOES 13, which may show a direct observation of EMIC waves scattering relativistic electrons.

  5. Sam37 is crucial for formation of the mitochondrial TOM–SAM supercomplex, thereby promoting β-barrel biogenesis

    PubMed Central

    Wenz, Lena-Sophie; Ellenrieder, Lars; Qiu, Jian; Bohnert, Maria; Zufall, Nicole; van der Laan, Martin; Becker, Thomas

    2015-01-01

    Biogenesis of mitochondrial β-barrel proteins requires two preprotein translocases, the general translocase of the outer membrane (TOM) and the sorting and assembly machinery (SAM). TOM and SAM form a supercomplex that promotes transfer of β-barrel precursors. The SAM core complex contains the channel protein Sam50, which cooperates with Sam35 in precursor recognition, and the peripheral membrane protein Sam37. The molecular function of Sam37 has been unknown. We report that Sam37 is crucial for formation of the TOM–SAM supercomplex. Sam37 interacts with the receptor domain of Tom22 on the cytosolic side of the mitochondrial outer membrane and links TOM and SAM complexes. Sam37 thus promotes efficient transfer of β-barrel precursors to the SAM complex. We conclude that Sam37 functions as a coupling factor of the translocase supercomplex of the mitochondrial outer membrane. PMID:26416958

  6. A circularly permuted alpha-amylase-type alpha/beta-barrel structure in glucan-synthesizing glucosyltransferases.

    PubMed

    MacGregor, E A; Jespersen, H M; Svensson, B

    1996-01-15

    A motif of amino acid residues, located at the active site and specific beta-strands in alpha-amylases, is recognized in alpha-1,3- and alpha-1,6-glucan-synthesizing glucosyltransferases, leading to the conclusion that these enzymes contain an alpha/beta-barrel closely related to the (beta/alpha)8-fold of the alpha-amylase superfamily. The secondary structure elements of the transferase barrel, however, are circularly permuted to start with an alpha-helix equivalent to helix 3 in the alpha-amylases. Thus, the transferase counterpart of the long third beta-->alpha connection--constituting a domain in the alpha-amylases--is divided to precede and succeed the barrel. This architectural arrangement may be coupled to sucrose scission and glucosyl transfer. The involvement in the mechanism in glucosyltransferases of active site residues recurring in amylolytic enzymes is discussed.

  7. Developmental decline in modulation of glutamatergic synapses in layer IV of the barrel cortex by group II metabotropic glutamate receptors.

    PubMed

    Mateo, Z; Porter, J T

    2015-04-02

    Previously, we demonstrated that group II metabotropic glutamate receptors (mGluRs) reduce glutamate release from thalamocortical synapses during early postnatal development (P7-11). To further examine the role of group II mGluRs in the modulation of somatosensory circuitry, we determined whether group II mGluRs continue to modulate thalamocortical synapses until adulthood and whether these receptors also modulate intra-cortical synapses in the barrel cortex. To address these issues, we examined the effect of the group II mGluR agonists on thalamocortical excitatory postsynaptic currents (EPSCs) and intra-barrel EPSCs in slices from animals of different ages (P7-53). We found that the depression of thalamocortical EPSCs by group II mGluRs rapidly declined after the second postnatal week. In contrast, adenosine continued to depress thalamocortical EPSCs via a presynaptic mechanism in young adult mice (P30-50). Activation of group II mGluRs also reduced intra-barrel EPSCs through a postsynaptic mechanism in young mice (P7-11). Similar to the thalamocortical synapses, the group II mGluR modulation of intra-barrel excitatory synapses declined with development. In young adult animals (P30-50), group II mGluR stimulation had little effect on intra-barrel EPSCs but did hyperpolarize the neurons. Together our results demonstrate that group II mGluRs modulate barrel cortex circuitry by presynaptic and postsynaptic mechanisms depending on the source of the synapse and that this modulation declines with development.

  8. Effectiveness of low impact development practices in two urbanized watersheds: retrofitting with rain barrel/cistern and porous pavement.

    PubMed

    Ahiablame, Laurent M; Engel, Bernard A; Chaubey, Indrajeet

    2013-04-15

    The impacts of urbanization on hydrology and water quality can be minimized with the use of low impact development (LID) practices in urban areas. This study assessed the performance of rain barrel/cistern and porous pavement as retrofitting technologies in two urbanized watersheds of 70 and 40 km(2) near Indianapolis, Indiana. Six scenarios consisting of the watershed existing condition, 25% and 50% implementation of rain barrel/cistern and porous pavement, and 25% rain barrel/cistern combined with 25% porous pavement were evaluated using a proposed LID modeling framework and the Long-Term Hydrologic Impact Assessment (L-THIA)-LID model. The model was calibrated for annual runoff from 1991 to 2000, and validated from 2001 to 2010 for the two watersheds. For the calibration period, R(2) and NSE values were greater than 0.60 and 0.50 for annual runoff and streamflow. Baseflow was not calibrated in this study. During the validation period, R(2) and NSE values were greater than 0.50 for runoff and streamflow, and 0.30 for baseflow in the two watersheds. The various application levels of barrel/cistern and porous pavement resulted in 2-12% reduction in runoff and pollutant loads for the two watersheds. Baseflow loads slightly increased with increase in baseflow by more than 1%. However, reduction in runoff led to reduction in total streamflow and associated pollutant loads by 1-9% in the watersheds. The results also indicate that the application of 50% rain barrel/cistern, 50% porous pavement and 25% rain barrel/cistern combined with 25% porous pavement are good retrofitting options in these watersheds. The L-THIA-LID model can be used to inform management and decision-making for implementation of LID practices at the watershed scale.

  9. The Effects of CO2 Injection and Barrel Temperatures on the Physiochemical and Antioxidant Properties of Extruded Cereals

    PubMed Central

    Thin, Thazin; Myat, Lin; Ryu, Gi-Hyung

    2016-01-01

    The effects of CO2 injection and barrel temperatures on the physiochemical and antioxidant properties of extruded cereals (sorghum, barley, oats, and millet) were studied. Extrusion was carried out using a twin-screw extruder at different barrel temperatures (80, 110, and 140°C), CO2 injection (0 and 500 mL/min), screw speed of 200 rpm, and moisture content of 25%. Extrusion significantly increased the total flavonoid content (TFC) of extruded oats, and β-glucan and protein digestibility (PD) of extruded barley and oats. In contrast, there were significant reductions in 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, PD of extruded sorghum and millet, as well as resistant starch (RS) of extruded sorghum and barley, and total phenolic content (TPC) of all extrudates, except extruded millet. At a barrel temperature of 140°C, TPC in extruded barley was significantly increased, and there was also an increase in DPPH and PD in extruded millet with or without CO2 injection. In contrast, at a barrel temperature of 140°C, the TPC of extruded sorghum decreased, TFC of extruded oats decreased, and at a barrel temperature of 110°C, PD of extruded sorghum without CO2 decreased. Some physical properties [expansion ratio (ER), specific length, piece density, color, and water absorption index] of the extrudates were significantly affected by the increase in barrel temperature. The CO2 injection significantly affected some physical properties (ER, specific length, piece density, water solubility index, and water absorption index), TPC, DPPH, β-glucan, and PD. In conclusion, extruded barley and millet had higher potential for making value added cereal-based foods than the other cereals. PMID:27752504

  10. Double anterograde tracing of outputs from adjacent "barrel columns" of rat somatosensory cortex. Neostriatal projection patterns and terminal ultrastructure.

    PubMed

    Wright, A K; Norrie, L; Ingham, C A; Hutton, E A; Arbuthnott, G W

    1999-01-01

    The sensory input to the neostriatum from groups of cortical cells related to individual facial vibrissae has been investigated at both light- and electron-microscopic resolution. The purpose of the study was to establish the extent to which corticostriatal input maintains the anatomical coding of spatial information that is present in cortex. A double anterograde tracing method was used to identify the output projections from groups of adjacent neurons in different barrel columns, so that the anatomical relationships between two groups could be studied throughout their length. Adjacent whiskers are represented in adjoining cortical barrels and an examination of corticostriatal projections from these reveals two patterns of projection. In one, the anatomical topography is partially preserved; the barrels are represented in adjoining, discrete, areas of the somatosensory neostriatum. In the second projection pattern, the neostriatal innervation is diffuse and adjacent barrels are represented in overlapping regions of the neostriatum. Moreover, the fibres are thinner, have smaller boutons, and are present in both the ipsilateral and contralateral neostriatum. The two systems also enter the neostriatal neuropile separately. The discrete topographic system enters the adjacent neostriatum as collaterals which leave the descending corticofugal fibres at right angles, while the diffuse system enters directly from the corpus callosum at an acute angle. Examination of the neostriatal terminal fields by correlated light and electron microscopy, shows that characteristic axospinous terminals on spiny neurons are made by both groups of cortical fibres, although they differ in their size and morphology. It is concluded that at least two corticostriatal pathways arise from the barrel cortex. One connection maintains some of the anatomical code implicit in the barrel pattern of primary somatosensory cortex, but another, more diffuse, system is overlaid upon it which may carry

  11. The Effects of CO2 Injection and Barrel Temperatures on the Physiochemical and Antioxidant Properties of Extruded Cereals.

    PubMed

    Thin, Thazin; Myat, Lin; Ryu, Gi-Hyung

    2016-09-01

    The effects of CO2 injection and barrel temperatures on the physiochemical and antioxidant properties of extruded cereals (sorghum, barley, oats, and millet) were studied. Extrusion was carried out using a twin-screw extruder at different barrel temperatures (80, 110, and 140°C), CO2 injection (0 and 500 mL/min), screw speed of 200 rpm, and moisture content of 25%. Extrusion significantly increased the total flavonoid content (TFC) of extruded oats, and β-glucan and protein digestibility (PD) of extruded barley and oats. In contrast, there were significant reductions in 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, PD of extruded sorghum and millet, as well as resistant starch (RS) of extruded sorghum and barley, and total phenolic content (TPC) of all extrudates, except extruded millet. At a barrel temperature of 140°C, TPC in extruded barley was significantly increased, and there was also an increase in DPPH and PD in extruded millet with or without CO2 injection. In contrast, at a barrel temperature of 140°C, the TPC of extruded sorghum decreased, TFC of extruded oats decreased, and at a barrel temperature of 110°C, PD of extruded sorghum without CO2 decreased. Some physical properties [expansion ratio (ER), specific length, piece density, color, and water absorption index] of the extrudates were significantly affected by the increase in barrel temperature. The CO2 injection significantly affected some physical properties (ER, specific length, piece density, water solubility index, and water absorption index), TPC, DPPH, β-glucan, and PD. In conclusion, extruded barley and millet had higher potential for making value added cereal-based foods than the other cereals.

  12. Molecular correlates of cortical network modulation by long-term sensory experience in the adult rat barrel cortex

    PubMed Central

    Vallès, Astrid; Granic, Ivica; De Weerd, Peter; Martens, Gerard J.M.

    2014-01-01

    Modulation of cortical network connectivity is crucial for an adaptive response to experience. In the rat barrel cortex, long-term sensory stimulation induces cortical network modifications and neuronal response changes of which the molecular basis is unknown. Here, we show that long-term somatosensory stimulation by enriched environment up-regulates cortical expression of neuropeptide mRNAs and down-regulates immediate-early gene (IEG) mRNAs specifically in the barrel cortex, and not in other brain regions. The present data suggest a central role of neuropeptides in the fine-tuning of sensory cortical circuits by long-term experience. PMID:25171421

  13. Removal of GABAergic inhibition alters subthreshold input in neurons in forepaw barrel subfield (FBS) in rat first somatosensory cortex (SI) after digit stimulation.

    PubMed

    Li, Cheng X; Callaway, Joseph C; Waters, Robert S

    2002-08-01

    Our objective was to test the hypothesis that suppression of GABAergic inhibition results in an enhancement of responses to stimulation of the surround receptive field. Neurons in the forepaw barrel subfield (FBS) in rat first somatosensory cortex (SI) receive short latency suprathreshold input from a principal location on the forepaw and longer latency subthreshold input from surrounding forepaw skin regions. Input from principal and surround receptive field sites was examined before, during, and after administration of the GABA(A) receptor blocker bicuculline methiodide (BMI) (in 165 mM NaCl at pH 3.3-3.5). In vivo extracellular recording was used to first identify the location of the glabrous forepaw digit representation within the FBS. In vivo intracellular recording and labeling techniques were then used to impale single FBS neurons in layer IV as well as neurons in layers III and V, determine the receptive field of the cell, and fill the cell with biocytin for subsequent morphological identification. The intracellular recording electrode was fastened with dental wax to a double-barrel pipette for BMI iontophoresis and current balance. A stimulating probe, placed on the glabrous forepaw skin surface, was used to identify principal and surround components of the receptive field. Once a cell was impaled and a stable recording was obtained, a stimulating probe was placed at a selected site within the surround receptive field. Single-pulse stimulation (1 Hz) was then delivered through the skin probe and the percentage of spikes occurring in 1-min intervals before BMI onset was used as a baseline measure. BMI was then iontophoresed while the periphery was simultaneously stimulated, and spike percentage measured during and after BMI ejection was compared with the pre-BMI baseline. The major findings are: (1) suppression of GABAergic inhibition enhanced evoked responses to firing level from sites in surround receptive fields in 65% of the cells ( n=17); (2) evoked

  14. Detailed Surface Analysis Of Incremental Centrifugal Barrel Polishing (CBP) Of Single-Crystal Niobium Samples

    SciTech Connect

    Palczewski, Ari D.; Tian, Hui; Trofimova, Olga; Reece, Charles E.

    2011-07-01

    We performed Centrifugal Barrel Polishing (CBP) on single crystal niobium samples/coupons housed in a stainless steel sample holder following the polishing recipe developed at Fermi Lab (FNAL) in 2011 \\cite{C. A. Cooper 2011}. Post CBP, the sample coupons were analyzed for surface roughness, crystal composition and structure, and particle contamination. Following the initial analysis each coupon was high pressure rinsed (HRP) and analyzed for the effectiveness of contamination removal. We were able to obtain the mirror like surface finish after the final stage of tumbling, although some defects and embedded particles remained. In addition, standard HPR appears to have little effect on removing embedded particles which remain after each tumbling step, although final polishing media removal was partially affected by standard/extended HPR.

  15. Twenty barrel in situ pipe gun type solid hydrogen pellet injector for the Large Helical Device.

    PubMed

    Sakamoto, Ryuichi; Motojima, Gen; Hayashi, Hiromi; Inoue, Tomoyuki; Ito, Yasuhiko; Ogawa, Hideki; Takami, Shigeyuki; Yokota, Mitsuhiro; Yamada, Hiroshi

    2013-08-01

    A 20 barrel solid hydrogen pellet injector, which is able to inject 20 cylindrical pellets with a diameter and length of between 3.0 and 3.8 mm at the velocity of 1200 m/s, has been developed for the purpose of direct core fueling in LHD (Large Helical Device). The in situ pipe gun concept with the use of compact cryo-coolers enables stable operation as a fundamental facility in plasma experiments. The combination of the two types of pellet injection timing control modes, i.e., pre-programing mode and real-time control mode, allows the build-up and sustainment of high density plasma around the density limit. The pellet injector has demonstrated stable operation characteristics during the past three years of LHD experiments.

  16. A mutant with bilateral whisker to barrel inputs unveils somatosensory mapping rules in the cerebral cortex.

    PubMed

    Renier, Nicolas; Dominici, Chloe; Erzurumlu, Reha S; Kratochwil, Claudius F; Rijli, Filippo M; Gaspar, Patricia; Chédotal, Alain

    2017-03-28

    In mammals, tactile information is mapped topographically onto the contralateral side of the brain in the primary somatosensory cortex (S1). Here we describe that in Robo3 mouse mutants a sizeable fraction of the trigemino-thalamic inputs project ipsilaterally rather than contralaterally. The resulting mixture of crossed and uncrossed sensory inputs creates bilateral whisker maps in the thalamus and cortex. Surprisingly, these maps are segregated resulting in a duplication of whisker representations and a doubling of the number of barrels without changes of the S1 size. Sensory deprivation shows competitive interactions between the ipsi/contralateral whisker maps. This study reveals that the somatosensory system can form a somatotopic map to integrate bilateral sensory inputs but organizes the maps in a different way than in the visual, or auditory systems. Therefore, while the molecular pre-patterning constrains their orientation and position, the preservation of the continuity of inputs defines the layout of the somatosensory maps.

  17. Phenolic and Aroma Composition of White Wines Produced by Prolonged Maceration and Maturation in Wooden Barrels

    PubMed Central

    Jedrejčić, Nikolina; Ganić, Karin Kovačević; Staver, Mario; Peršurić, Đordano

    2015-01-01

    Summary To investigate the phenolic and aroma composition of Malvazija istarska (Vitis vinifera L.) white wines produced by an unconventional technology comprising prolonged maceration followed by maturation in wooden barrels, representative samples were subjected to analysis by UV/Vis spectrometry, high-performance liquid chromatography, and gas chromatography-mass spectrometry. When compared to standard wines, the investigated samples contained higher levels of dry extract, volatile acidity, lactic acid, phenols, colour intensity, antioxidant activity, majority of monoterpenes, C13-norisoprenoids, methanol, higher alcohols, ethyl acetate, branched-chain esters and esters of hydroxy and dicarboxylic acids, ethylphenols, furans, and acetals, as well as lower levels of malic acid, β-damascenone, straight-chain fatty acids, ethyl and acetate esters. It was estimated that maceration had a stronger influence on phenols, and maturation on volatile aromas. Despite different vintages and technological details, the investigated wines showed a relative homogeneity in the composition, representing a clear and distinctive type. PMID:27904375

  18. Light yield of Kuraray SCSF-78MJ scintillating fibers for the Gluex barrel calorimeter

    SciTech Connect

    Beattie, T D; Fischer, A P; Krueger, S T; Lolos, G J; Papandreou, Z; Plummer, E L; Semenov, A Yu; Semenova, I A; Sichello, L M; Teigro, L A; Smith, E S

    2014-09-01

    Over three quarters of a million 1-mm-diameter 4-m-long Kuraray double-clad SCSF-78MJ (blue-green) scintillating fibers have been used in the construction of the GlueX electromagnetic barrel calorimeter for the Hall D experimental program at Jefferson Lab. The quality of a random sample of 4,750 of these fibers was evaluated by exciting the fibers at their mid point using a 90Sr source in order to determine the light yield using a calibrated vacuum photomultiplier as the photosensor. A novel methodology was developed to extract the number of photoelectrons detected for measurements where individual photoelectron peaks are not discernible. The average number of photoelectrons from this sample of fibers was 9.17±0.6 at a source distance of 200 cm from the PMT.

  19. Microcircuits of excitatory and inhibitory neurons in layer 2/3 of mouse barrel cortex.

    PubMed

    Avermann, Michael; Tomm, Christian; Mateo, Celine; Gerstner, Wulfram; Petersen, Carl C H

    2012-06-01

    Synaptic interactions between nearby excitatory and inhibitory neurons in the neocortex are thought to play fundamental roles in sensory processing. Here, we have combined optogenetic stimulation, whole cell recordings, and computational modeling to define key functional microcircuits within layer 2/3 of mouse primary somatosensory barrel cortex. In vitro optogenetic stimulation of excitatory layer 2/3 neurons expressing channelrhodopsin-2 evoked a rapid sequence of excitation followed by inhibition. Fast-spiking (FS) GABAergic neurons received large-amplitude, fast-rising depolarizing postsynaptic potentials, often driving action potentials. In contrast, the same optogenetic stimulus evoked small-amplitude, subthreshold postsynaptic potentials in excitatory and non-fast-spiking (NFS) GABAergic neurons. To understand the synaptic mechanisms underlying this network activity, we investigated unitary synaptic connectivity through multiple simultaneous whole cell recordings. FS GABAergic neurons received unitary excitatory postsynaptic potentials with higher probability, larger amplitudes, and faster kinetics compared with NFS GABAergic neurons and other excitatory neurons. Both FS and NFS GABAergic neurons evoked robust inhibition on postsynaptic layer 2/3 neurons. A simple computational model based on the experimentally determined electrophysiological properties of the different classes of layer 2/3 neurons and their unitary synaptic connectivity accounted for key aspects of the network activity evoked by optogenetic stimulation, including the strong recruitment of FS GABAergic neurons acting to suppress firing of excitatory neurons. We conclude that FS GABAergic neurons play an important role in neocortical microcircuit function through their strong local synaptic connectivity, which might contribute to driving sparse coding in excitatory layer 2/3 neurons of mouse barrel cortex in vivo.

  20. Water relations and photosynthesis of a barrel cactus, Ferocactus acanthodes, in the Colorado desert.

    PubMed

    Nobel, Park S

    1977-06-01

    The structural characteristics, water relations, and photosynthesis of Ferocactus acanthodes (Lemaire) Britton and Rose, a barrel cactus exhibiting Crassulacean acid metabolism (CAM), were examined in its native habitat in the western Colorado desert. Water storage in its succulent stem permitted nighttime stomatal opening ot continue for about 40 days after the soil water potential became less than that of the stem, a period whe the plant would be unable to extract water from the soil. After 7 months of drought and consequent unreplenished water loss from a plant, diurnal stomatal activity was not observed and the stem osmotic pressure was 6.4 bars, more than double the value measured during wet periods with nighttime stomatal opening. F. acanthodes had a shallow root system (mean depth of 8 cm) which responded within 24 h to rainfall.When the nocturnal stem surface temperature was raised from 8.0° C to 35.0° C, the stomatal resistance increased 4-fold, indicating that cool nighttime temperatures are advantageous for gas exchange by F. acanthodes. Moreover, the optimal temperature for CO2 uptake in the dark was only 12.6° C. CO2 uptake at night became maximal for 3.0 mEinsteins cm(-2) of photosynthetically active radiation incident during the preceding day, and the minimum number of incident quanta absorbed per CO2 fixed was 68. The transpiration ratio (mass of water transpired/mass of CO2 fixed) had the relatively low value of 70 for an entire year, consistent with values obtained for other CAM plants. The total amount of water annually diverted to the floral structures was about 6% of the stem wet weight. The annual growth increment estimated from the net CO2 assimilation corresponded to about 10% of the stem mass for barrel cacti 34 cm tall, in agreement with measured dimension changes, and indicated that such plants were about 26 years old.

  1. Lhx2 regulates a cortex-specific mechanism for barrel formation

    PubMed Central

    Shetty, Ashwin S.; Godbole, Geeta; Maheshwari, Upasana; Padmanabhan, Hari; Chaudhary, Rahul; Muralidharan, Bhavana; Hou, Pei-Shan; Monuki, Edwin S.; Kuo, Hung-Chih; Rema, V.; Tole, Shubha

    2013-01-01

    LIM homeodomain transcription factors are critical regulators of early development in multiple systems but have yet to be examined for a role in circuit formation. The LIM homeobox gene Lhx2 is expressed in cortical progenitors during development and also in the superficial layers of the neocortex in maturity. However, analysis of Lhx2 function at later stages of cortical development has been hampered by severe phenotypes associated with early loss of function. We identified a particular Cre-recombinase line that acts in the cortical primordium after its specification is complete, permitting an analysis of Lhx2 function in neocortical lamination, regionalization, and circuit formation by selective elimination of Lhx2 in the dorsal telencephalon. We report a profound disruption of cortical neuroanatomical and molecular features upon loss of Lhx2 in the cortex from embryonic day 11.5. A unique feature of cortical circuitry, the somatosensory barrels, is undetectable, and molecular patterning of cortical regions appears disrupted. Surprisingly, thalamocortical afferents innervate the mutant cortex with apparently normal regional specificity. Electrophysiological recordings reveal a loss of responses evoked by stimulation of individual whiskers, but responses to simultaneous stimulation of multiple whiskers were present, suggesting that thalamic afferents are unable to organize the neurocircuitry for barrel formation because of a cortex-specific requirement of Lhx2. We report that Lhx2 is required for the expression of transcription factor paired box gene 6, axon guidance molecule Ephrin A5, and the receptor NMDA receptor 1. These genes may mediate Lhx2 function in the formation of specialized neurocircuitry necessary for neocortical function. PMID:24262147

  2. Insights into the Fold Organization of TIM Barrel from Interaction Energy Based Structure Networks

    PubMed Central

    Vijayabaskar, M. S.; Vishveshwara, Saraswathi

    2012-01-01

    There are many well-known examples of proteins with low sequence similarity, adopting the same structural fold. This aspect of sequence-structure relationship has been extensively studied both experimentally and theoretically, however with limited success. Most of the studies consider remote homology or “sequence conservation” as the basis for their understanding. Recently “interaction energy” based network formalism (Protein Energy Networks (PENs)) was developed to understand the determinants of protein structures. In this paper we have used these PENs to investigate the common non-covalent interactions and their collective features which stabilize the TIM barrel fold. We have also developed a method of aligning PENs in order to understand the spatial conservation of interactions in the fold. We have identified key common interactions responsible for the conservation of the TIM fold, despite high sequence dissimilarity. For instance, the central beta barrel of the TIM fold is stabilized by long-range high energy electrostatic interactions and low-energy contiguous vdW interactions in certain families. The other interfaces like the helix-sheet or the helix-helix seem to be devoid of any high energy conserved interactions. Conserved interactions in the loop regions around the catalytic site of the TIM fold have also been identified, pointing out their significance in both structural and functional evolution. Based on these investigations, we have developed a novel network based phylogenetic analysis for remote homologues, which can perform better than sequence based phylogeny. Such an analysis is more meaningful from both structural and functional evolutionary perspective. We believe that the information obtained through the “interaction conservation” viewpoint and the subsequently developed method of structure network alignment, can shed new light in the fields of fold organization and de novo computational protein design. PMID:22615547

  3. Interplay between Drying and Stability of a TIM Barrel Protein: A Combined Simulation-Experimental Study

    PubMed Central

    Das, Payel; Kapoor, Divya; Halloran, Kevin T.; Zhou, Ruhong; Matthews, C. Robert

    2013-01-01

    Recent molecular dynamics simulations have suggested important roles for nanoscale dewetting on the stability, function, and folding dynamics of proteins. Using a synergistic simulation-experimental approach on the αTS TIM barrel protein, we validate this hypothesis by revealing the occurrence of drying inside hydrophobic amino acid clusters and its manifestation on experimental measures of protein stability and structure. Cavities created within three clusters of branched aliphatic amino acids, isoleucines, leucines and valines (ILV), were found to experience strong water density fluctuations or intermittent dewetting transitions in simulations. Individually substituting 10 residues in the large ILV cluster at the N-terminus with the less hydrophobic alanine showed a weakening or diminishing effect on dewetting that depended on the site of the mutation. Our simulations also demonstrated that replacement of buried leucines with the isosteric and polar asparagine enhanced the wetting of the N- and C-terminal clusters. Experimental results on the stability, secondary structure and compactness of the native and intermediate states for the asparagine variants are consistent with the preferential drying of the large N-terminal cluster in the intermediate. By contrast, the region encompassing the small C-terminal cluster only experiences partial drying in the intermediate and its structure and stability are unaffected by the asparagine substitution. Surprisingly, the structural distortions required to accommodate the replacement of leucine by asparagine in the N-terminal cluster revealed the existence of alternative stable folds in the native basin. This combined simulation-experimental study demonstrates the critical role of drying in hydrophobic ILV clusters to the folding and stability of the αTS TIM barrel. PMID:23293932

  4. Material wear and failure mode analysis of breakfast cereal extruder barrels and screw elements

    NASA Astrophysics Data System (ADS)

    Mastio, Michael Joseph, Jr.

    2005-11-01

    Nearly seventy-five years ago, the single screw extruder was introduced as a means to produce metal products. Shortly after that, the extruder found its way into the plastics industry. Today much of the world's polymer industry utilizes extruders to produce items such as soda bottles, PVC piping, and toy figurines. Given the significant economical advantages of extruders over conventional batch flow systems, extruders have also migrated into the food industry. Food applications include the meat, pet food, and cereal industries to name just a few. Cereal manufacturers utilize extruders to produce various forms of Ready-to-Eat (RTE) cereals. These cereals are made from grains such as rice, oats, wheat, and corn. The food industry has been incorrectly viewed as an extruder application requiring only minimal energy control and performance capability. This misconception has resulted in very little research in the area of material wear and failure mode analysis of breakfast cereal extruders. Breakfast cereal extruder barrels and individual screw elements are subjected to the extreme pressures and temperatures required to shear and cook the cereal ingredients, resulting in excessive material wear and catastrophic failure of these components. Therefore, this project focuses on the material wear and failure mode analysis of breakfast cereal extruder barrels and screw elements, modeled as a Discrete Time Markov Chain (DTMC) process in which historical data is used to predict future failures. Such predictive analysis will yield cost savings opportunities by providing insight into extruder maintenance scheduling and interchangeability of screw elements. In this DTMC wear analysis, four states of wear are defined and a probability transition matrix is determined based upon 24,041 hours of operational data. This probability transition matrix is used to predict when an extruder component will move to the next state of wear and/or failure. This information can be used to determine

  5. Characterizing radiation belt electron precipitation losses using BARREL (Balloon Array for RBSP Relativistic Electron Losses) data.

    NASA Astrophysics Data System (ADS)

    Bowers, G. S.; Smith, D. M.; Millan, R. M.; Sample, J. G.; McCarthy, M.; Woodger, L. A.; Halford, A. J.; Liang, X.

    2015-12-01

    Precipitation loss is a process whereby charged particles trapped in the radiation belts scatter into the Earth's atmosphere and are removed from the belt population. Balloon-borne x-ray detectors and satellites like SAMPEX have generally observed precipitation losses of three types, here characterized by their MLT distribution and related e-folding energy of the inferred precipitating electron energy spectrum, the third characterized by its burstiness and brief duration: soft (isotropic in MLT with e-folding for balloons between 50-100 keV, for SAMPEX between 100-300 keV), hard (concentrated in the dusk-to-midnight sector with e-folding for balloons > 200 keV, for SAMPEX > 400 keV), and microbursts (concentrated in the dawn-to-noon sector, bursty and very short temporal structure < 1s). Soft precipitation occurs much more often than the others, but has received less attention in the literature even though recent analysis of observed SAMPEX losses has shown that soft precipitation may account for the greatest electron loss from the quiet time radiation belts. The goal of this project is to compare/reconcile the different spectral characterizations of soft precipitation observed by BARREL and SAMPEX, and seek to understand the wave scattering mechanisms responsible for these losses.For this work we will present the 2013/2014 observed BARREL precipitation events cataloged according to type, (soft, hard, microburst), MLT and L distribution, and geomagnetic/space weather conditions. In particular, we will use Van Allen Probe data to define the state of the belts and the position of the balloon relative to the plasmapause and trapping boundary before and after precipitation events.

  6. Determination of local optical properties of the rat barrel cortex during neural activation: Monte-Carlo approach to light propagation

    NASA Astrophysics Data System (ADS)

    Migacheva, E. V.; Chamot, S. R.; Seydoux, O.; Weber, B.; Depeursinge, C.; Marquet, P.; Magistretti, P. J.

    2010-04-01

    Spatially-spectrally-resolved reflectance measurements allow in vivo measuring the optical coefficients of absorption and scattering within the cortical tissue. This method, if applied to neural tissue during enhanced activity, could allow a straightforward monitoring of the blood oxygen saturation changes occurring in the brain cortex during hemodynamic responses. Furthermore, it may provide valuable information on possible absorption and scattering changes occurring during stimulation. The feasibility of such measurements was investigated by carrying a preliminary numerical study using a Monte-Carlo light propagation routine. Experimental parameters such as the geometry of the optical probe, baseline cortex optical coefficients retrieved from the literature and anatomical characteristics of the rat barrel cortex were used as an input for the simulations. The sensitivity of the probe to the local variations of optical coefficients was investigated with this numerical approach. Additionally, the influence of the barrel cortex dimensions and the probe positioning relatively to the activated region were studied for instrumental optimization purpose. It was found that typical variations of optical coefficients can be detected if the activated region of barrel cortex has a volume of typically 1 mm3 or larger. The decay of the probe sensitivity to changes was studied as a function of the depth of the activated region. The results showed that the best sensitivity is achieved by placing the light injection fiber of the optical probe aligned onto the center of the cylindrical barrel.

  7. Molecular Correlates of Cortical Network Modulation by Long-Term Sensory Experience in the Adult Rat Barrel Cortex

    ERIC Educational Resources Information Center

    Vallès, Astrid; Granic, Ivica; De Weerd, Peter; Martens, Gerard J. M.

    2014-01-01

    Modulation of cortical network connectivity is crucial for an adaptive response to experience. In the rat barrel cortex, long-term sensory stimulation induces cortical network modifications and neuronal response changes of which the molecular basis is unknown. Here, we show that long-term somatosensory stimulation by enriched environment…

  8. Construction of Ag/AgCl Reference Electrode from Used Felt-Tipped Pen Barrel for Undergraduate Laboratory

    ERIC Educational Resources Information Center

    Inamdar, Shaukatali N.; Bhat, Mohsin A.; Haram, Santosh K.

    2009-01-01

    A reference electrode is one of the prerequisites of electrochemical investigations. Many electrodes are commercially available but are expensive and prone to accidental breakage by students. Here we report a simple, easy-to-fabricate, inexpensive, reliable, unbreakable, and reproducible Ag/AgCl reference electrode. The empty barrel of a…

  9. Texture coarseness responsive neurons and their mapping in layer 2–3 of the rat barrel cortex in vivo

    PubMed Central

    Garion, Liora; Dubin, Uri; Rubin, Yoav; Khateb, Mohamed; Schiller, Yitzhak; Azouz, Rony; Schiller, Jackie

    2014-01-01

    Texture discrimination is a fundamental function of somatosensory systems, yet the manner by which texture is coded and spatially represented in the barrel cortex are largely unknown. Using in vivo two-photon calcium imaging in the rat barrel cortex during artificial whisking against different surface coarseness or controlled passive whisker vibrations simulating different coarseness, we show that layer 2–3 neurons within barrel boundaries differentially respond to specific texture coarsenesses, while only a minority of neurons responded monotonically with increased or decreased surface coarseness. Neurons with similar preferred texture coarseness were spatially clustered. Multi-contact single unit recordings showed a vertical columnar organization of texture coarseness preference in layer 2–3. These findings indicate that layer 2–3 neurons perform high hierarchical processing of tactile information, with surface coarseness embodied by distinct neuronal subpopulations that are spatially mapped onto the barrel cortex. DOI: http://dx.doi.org/10.7554/eLife.03405.001 PMID:25233151

  10. Production of transgenic barrel medic (Medicago truncatula Gaernt.) using the ipt-type MAT vector system and impairment of Recombinase-mediated excision events.

    PubMed

    Scaramelli, L; Balestrazzi, A; Bonadei, M; Piano, E; Carbonera, D; Confalonieri, M

    2009-02-01

    Expression of the uidA reporter gene was tested in transformation experiments of barrel medic (Medicago truncatula Gaertn.) with the ipt-type control vectors pIPT5, pIPT10 and pIPT20 and distinct in vitro culture conditions. The highest GUS expression levels were obtained with the pIPT10 construct carrying the ipt gene under the control of the native ipt promoter and using kanamycin as selective agent. The ipt-shooty transformants, characterized by the absence of both rooting ability and apical dominance associated with vitrification, were easily identified by visual selection. Using only the ipt gene as selectable marker, we obtained a stable transformation frequency of 9.8% with pIPT10 construct. The ipt-type MAT vector pEXM2 was then used to monitor the excision events mediated by the yeast Recombinase and the consequent production of ipt marker-free transgenic plants. Transgenic ipt-shooty lines were recovered at a frequency of 7.9% in the absence of kanamycin-based selection. The ipt-shooty phenotype was maintained in all the transgenic lines and no reversion to the normal phenotype occurred. PCR analysis revealed the presence of the 'hit and run' cassette in the genome of all the regenerated ipt-shooty lines while RT-PCR experiments confirmed the expression of the R gene, encoding the yeast Recombinase. A detailed molecular investigation, carried out to verify the integrity of the RS sites, revealed that these regions were intact in most cases. Our results with barrel medic suggest that the MAT system must be carefully evaluated and discussed on a case by case basis.

  11. Summary of types of radiation belt electron precipitation observed by BARREL

    NASA Astrophysics Data System (ADS)

    Halford, Alexa

    2016-07-01

    The Balloon Array for Relativistic Radiation belt Electron Loss (BARREL) was able to infer precipitation of radiation belt electrons on multiple time scales and due to multiple loss mechanisms. One storm will be specifically highlighted which occurred on 26 January 2013 when a solar wind shock hit the Earth. Although MeV electrons were observed to be lost due to an EMIC wave event [Zhang et al in prep], and multiple periods of electron loss during substorms were observed [Rae et al submitted JGR, Mann et al in prep], we will consider an event period where loss associated with multiple time scales, and thus possibly different loss mechanisms was observed from 1000 - 1200 UT on 26 January 2013. At about 1005 UT on 26 January 2013 an injection of radiation belt electrons followed by drift echoes for energies of ˜80 - 400 keV. BARREL observed X-rays with energies less than 180 keV associated with multiple temporal structures during the drift echo event period. The Van Allen Probes were at similar L-values but upwards of 2 hours away in MLT. Upper band chorus and ULF waves were observed during the event period. Throughout the beginning of the event period, microbursts were clearly observed. During this time lower band chorus waves as well as time domain structures were observed at Van Allen Probe A located upwards of 2 hours away in MLT. This large difference in MLT meant that neither potential loss mechanism was able to be clearly associated with the microbursts. As the lower band chorus and time domain structures were observed to recede, the microbursts were also observed to subside. ULF time scale modulation of the X-rays was also observed throughout most of the event period. We will examine if the ULF waves are the cause of the precipitation themselves, or are modulating the loss of particles from a secondary loss mechanism [Brito et al 2015 JGR, Rae et al Submitted JGR]. Although the 100s ms and ULF time scales are clearly observed, there is an ˜20 minute

  12. Patterns of population structure and dispersal in the long-lived "redwood" of the coral reef, the giant barrel sponge ( Xestospongia muta)

    NASA Astrophysics Data System (ADS)

    Richards, Vincent P.; Bernard, Andrea M.; Feldheim, Kevin A.; Shivji, Mahmood S.

    2016-09-01

    Sponges are one of the dominant fauna on Florida and Caribbean coral reefs, with species diversity often exceeding that of scleractinian corals. Despite the key role of sponges as structural components, habitat providers, and nutrient recyclers in reef ecosystems, their dispersal dynamics are little understood. We used ten microsatellite markers to study the population structure and dispersal patterns of a prominent reef species, the giant barrel sponge ( Xestospongia muta), the long-lived "redwood" of the reef, throughout Florida and the Caribbean. F-statistics, exact tests of population differentiation, and Bayesian multi-locus genotype analyses revealed high levels of overall genetic partitioning ( F ST = 0.12, P = 0.001) and grouped 363 individuals collected from the Bahamas, Honduras, US Virgin Islands, Key Largo (Florida), and the remainder of the Florida reef tract into at minimum five genetic clusters ( K = 5). Exact tests, however, revealed further differentiation, grouping sponges sampled from five locations across the Florida reef tract (~250 km) into three populations, suggesting a total of six genetic populations across the eight locations sampled. Assignment tests showed dispersal over ecological timescales to be limited to relatively short distances, as the only migration detected among populations was within the Florida reef tract. Consequently, populations of this major coral reef benthic constituent appear largely self-recruiting. A combination of levels of genetic differentiation, genetic distance, and assignment tests support the important role of the Caribbean and Florida currents in shaping patterns of contemporary and historical gene flow in this widespread coral reef species.

  13. Lipid Bilayer-Bound Conformation of an Integral Membrane Beta Barrel Protein by Multidimensional MAS NMR

    PubMed Central

    Eddy, Matthew T.; Su, Yongchao; Silvers, Robert; Andreas, Loren; Clark, Lindsay; Wagner, Gerhard; Pintacuda, Guido; Emsley, Lyndon; Griffin, Robert G.

    2015-01-01

    The human voltage dependent anion channel 1 (VDAC) is a 32 kDa β-barrel integral membrane protein that controls the transport of ions across the outer mitochondrial membrane. Despite the determination of VDAC solution and diffraction structures, a structural basis for the mechanism of its function is not yet fully understood. Biophysical studies suggest VDAC requires a lipid bilayer to achieve full function, motivating the need for atomic resolution structural information of VDAC in a membrane environment. Here we report an essential step toward that goal: extensive assignments of backbone and side chain resonances for VDAC in DMPC lipid bilayers via magic angle spinning nuclear magnetic resonance (MAS NMR). VDAC reconstituted into DMPC lipid bilayers spontaneously forms 2-dimensional lipid crystals, showing remarkable spectral resolution (0.5–0.3 ppm for 13C line width and less than 0.5 ppm 15N line widths at 750 MHz). In addition to the benefits of working in a lipid bilayer, several distinct advantages are observed with the lipid crystalline preparation. First, the strong signals and sharp line widths facilitated extensive NMR resonance assignments for an integral membrane β-barrel protein in lipid bilayers by MAS NMR. Second, a large number of residues in loop regions were readily observed and assigned, which can be challenging in detergent-solubilized membrane proteins where loop regions are often not detected due to line broadening from conformational exchange. Third, complete backbone and side chain chemical shift assignments could be obtained for the first 25 residues, which comprise the functionally important N-terminus. The reported assignments allow us to compare predicted torsion angles for VDAC prepared in DMPC 2D lipid crystals, DMPC liposomes, and LDAO-solubilized samples to address the possible effects of the membrane mimetic environment on the conformation of the protein. Concluding, we discuss the strengths and weaknesses of the reported

  14. Lipid bilayer-bound conformation of an integral membrane beta barrel protein by multidimensional MAS NMR.

    PubMed

    Eddy, Matthew T; Su, Yongchao; Silvers, Robert; Andreas, Loren; Clark, Lindsay; Wagner, Gerhard; Pintacuda, Guido; Emsley, Lyndon; Griffin, Robert G

    2015-04-01

    The human voltage dependent anion channel 1 (VDAC) is a 32 kDa β-barrel integral membrane protein that controls the transport of ions across the outer mitochondrial membrane. Despite the determination of VDAC solution and diffraction structures, a structural basis for the mechanism of its function is not yet fully understood. Biophysical studies suggest VDAC requires a lipid bilayer to achieve full function, motivating the need for atomic resolution structural information of VDAC in a membrane environment. Here we report an essential step toward that goal: extensive assignments of backbone and side chain resonances for VDAC in DMPC lipid bilayers via magic angle spinning nuclear magnetic resonance (MAS NMR). VDAC reconstituted into DMPC lipid bilayers spontaneously forms two-dimensional lipid crystals, showing remarkable spectral resolution (0.5-0.3 ppm for (13)C line widths and <0.5 ppm (15)N line widths at 750 MHz). In addition to the benefits of working in a lipid bilayer, several distinct advantages are observed with the lipid crystalline preparation. First, the strong signals and sharp line widths facilitated extensive NMR resonance assignments for an integral membrane β-barrel protein in lipid bilayers by MAS NMR. Second, a large number of residues in loop regions were readily observed and assigned, which can be challenging in detergent-solubilized membrane proteins where loop regions are often not detected due to line broadening from conformational exchange. Third, complete backbone and side chain chemical shift assignments could be obtained for the first 25 residues, which comprise the functionally important N-terminus. The reported assignments allow us to compare predicted torsion angles for VDAC prepared in DMPC 2D lipid crystals, DMPC liposomes, and LDAO-solubilized samples to address the possible effects of the membrane mimetic environment on the conformation of the protein. Concluding, we discuss the strengths and weaknesses of the reported

  15. Health physics activities in support of the thermal shield removal/disposal and core support barrel repair at the St. Lucie Nuclear Power Plant.

    PubMed

    Maisler, J J; Buchanan, H F

    1988-02-01

    The health physics activities related to the removal and disposal of a thermal shield at a nuclear power plant and subsequent repairs to the core support barrel required increased planning relative to a normal refueling/maintenance outage. The repair of the core support barrel was a "first" in the nuclear power industry. Pre-job planning was of great concern because of extremely high radiation levels associated with the irradiated stainless steel thermal shield and core support barrel. ALARA techniques used in the preparation of the thermal shield for removal and shipment to the disposal site are discussed.

  16. Tactile Experience Induces c-fos Expression in Rat Barrel Cortex

    PubMed Central

    Filipkowski, Robert K.; Rydz, Marek; Berdel, Bozena; Morys, Janusz; Kaczmarek, Leszek

    2000-01-01

    Understanding gene expression that is responsive to sensory stimulation is central to elucidate molecular mechanisms underlying neuronal plasticity. In this study we demonstrate two new methods of stimulating whiskers that provide major sensory input to rat neocortex. In the first paradigm, animals were placed on the top of a cylinder and their vibrissae were brushed by hand. In the second paradigm, animals were placed for a brief period of time into a new, wired cage resulting in vibrissae stimulation when they explored the new environment. Both approaches induced c-Fos expression in barrel cortex corresponding to the stimulated vibrissae, especially in layer IV. Layers II/III and V/VI also showed c-Fos induction, but there were no detectable changes in layer VIb. The majority of c-Fos-expressing cells are probably not inhibitory neurons, because they do not show parvalbumin staining. Both paradigms, in contrast to the previous methods, are simple to use and do not require anesthesia, restraint of animals, or elaborate experimental setups. PMID:10753978

  17. Oral creatine supplementation on performance of Quarter Horses used in barrel racing.

    PubMed

    Teixeira, F A; Araújo, A L; Ramalho, L O; Adamkosky, M S; Lacerda, T F; Coelho, C S

    2016-06-01

    The aim of this study was to evaluate the effects of oral creatine supplementation on the athletic performance of equines used for barrel racing. Ten healthy Quarter Horses, or Quarter Horse crossbred, weighing 429.7 ± 25.3 kg and with mean age of 3.8 ± 1.2 years, were used. Animals were evaluated in four different moments (M1, M2, M3, M4), and between M3 and M4, they were supplemented with 28 g of creatine/100 kg of body weight, orally, for 45 days. Although significant alterations for LDH activity, plasma glucose and packed cell volume were observed, it was possible to conclude that there was no improvement in the athletic performance for the animals used on the experiment, as there were no changes in time scores, heart rate and plasma lactate, variables considered as performance indicators, before and after supplementation.

  18. Coordinated Plasticity between Barrel Cortical Glutamatergic and GABAergic Neurons during Associative Memory

    PubMed Central

    Yan, Fenxia; Gao, Zilong; Chen, Pin; Huang, Li; Wang, Dangui; Chen, Na; Wu, Ruixiang; Feng, Jing; Cui, Shan; Lu, Wei

    2016-01-01

    Neural plasticity is associated with memory formation. The coordinated refinement and interaction between cortical glutamatergic and GABAergic neurons remain elusive in associative memory, which we examine in a mouse model of associative learning. In the mice that show odorant-induced whisker motion after pairing whisker and odor stimulations, the barrel cortical glutamatergic and GABAergic neurons are recruited to encode the newly learnt odor signal alongside the innate whisker signal. These glutamatergic neurons are functionally upregulated, and GABAergic neurons are refined in a homeostatic manner. The mutual innervations between these glutamatergic and GABAergic neurons are upregulated. The analyses by high throughput sequencing show that certain microRNAs related to regulating synapses and neurons are involved in this cross-modal reflex. Thus, the coactivation of the sensory cortices through epigenetic processes recruits their glutamatergic and GABAergic neurons to be the associative memory cells as well as drive their coordinated refinements toward the optimal state for the storage of the associated signals. PMID:28070425

  19. Variable Temporal Integration of Stimulus Patterns in the Mouse Barrel Cortex.

    PubMed

    Pitas, Anna; Albarracín, Ana Lía; Molano-Mazón, Manuel; Maravall, Miguel

    2016-02-01

    Making sense of the world requires distinguishing temporal patterns and sequences lasting hundreds of milliseconds or more. How cortical circuits integrate over time to represent specific sensory sequences remains elusive. Here we assessed whether neurons in the barrel cortex (BC) integrate information about temporal patterns of whisker movements. We performed cell-attached recordings in anesthetized mice while delivering whisker deflections at variable intervals and compared the information carried by neurons about the latest interstimulus interval (reflecting sensitivity to instantaneous frequency) and earlier intervals (reflecting integration over timescales up to several hundred milliseconds). Neurons carried more information about the latest interval than earlier ones. The amount of temporal integration varied with neuronal responsiveness and with the cortical depth of the recording site, that is, with laminar location. A subset of neurons in the upper layers displayed the strongest integration. Highly responsive neurons in the deeper layers encoded the latest interval but integrated particularly weakly. Under these conditions, BC neurons act primarily as encoders of current stimulation parameters; however, our results suggest that temporal integration over hundreds of milliseconds can emerge in some neurons within BC.

  20. Detergent-associated Solution Conformations of Helical and Beta-barrel Membrane Proteins

    SciTech Connect

    Mo, Yiming; Lee, Byung-Kwon; Ankner, John Francis; Becker, Jeffrey Marvin; Heller, William T

    2008-01-01

    Membrane proteins present major challenges for structural biology. In particular, the production of suitable crystals for high-resolution structural determination continues to be a significant roadblock for developing an atomic-level understanding of these vital cellular systems. The use of detergents for extracting membrane proteins from the native membrane for either crystallization or reconstitution into model lipid membranes for further study is assumed to leave the protein with the proper fold with a belt of detergent encompassing the membrane-spanning segments of the structure. Small-angle X-ray scattering was used to probe the detergent-associated solution conformations of three membrane proteins, namely bacteriorhodopsin (BR), the Ste2p G-protein coupled receptor from Saccharomyces cerevisiae, and the Escherichia coli porin OmpF. The results demonstrate that, contrary to the traditional model of a detergent-associated membrane protein, the helical proteins BR and Ste2p are not in the expected, compact conformation and associated with detergent micelles, while the ?-barrel OmpF is indeed embedded in a disk-like micelle in a properly folded state. The comparison provided by the BR and Ste2p, both members of the 7TM family of helical membrane proteins, further suggests that the interhelical interactions between the transmembrane helices of the two proteins differ, such that BR, like other rhodopsins, can properly refold to crystallize, while Ste2p continues to prove resistant to crystallization from an initially detergent-associated state.

  1. The impact of development and sensory deprivation on dendritic protrusions in the mouse barrel cortex.

    PubMed

    Chen, Chia-Chien; Bajnath, Adesh; Brumberg, Joshua C

    2015-06-01

    Dendritic protrusions (spines and filopodia) are structural indicators of synapses that have been linked to neuronal learning and memory through their morphological alterations induced by development and experienced-dependent activities. Although previous studies have demonstrated that depriving sensory experience leads to structural changes in neocortical organization, the more subtle effects on dendritic protrusions remain unclear, mostly due to focus on only one specific cell type and/or age of manipulation. Here, we show that sensory deprivation induced by whisker trimming influences the dendritic protrusions of basilar dendrites located in thalamocortical recipient lamina (IV and VI) of the mouse barrel cortex in a layer-specific manner. Following 1 month of whisker trimming after birth, the density of dendritic protrusions increased in layer IV, but decreased in layer VI. Whisker regrowth for 1 month returned protrusion densities to comparable level of age-matched controls in layer VI, but not in layer IV. In adults, chronic sensory deprivation led to an increase in protrusion densities in layer IV, but not in layer VI. In addition, chronic pharmacological blockade of N-methyl-d-aspartate receptors (NMDARs) increased protrusion density in both layers IV and VI, which returned to the control level after 1 month of drug withdrawal. Our data reveal that different cortical layers respond to chronic sensory deprivation in different ways, with more pronounced effects during developmental critical periods than adulthood. We also show that chronically blocking NMDARs activity during developmental critical period also influences the protrusion density and morphology in the cerebral cortex.

  2. A lipoprotein/β-barrel complex monitors lipopolysaccharide integrity transducing information across the outer membrane

    PubMed Central

    Konovalova, Anna; Mitchell, Angela M; Silhavy, Thomas J

    2016-01-01

    Lipoprotein RcsF is the OM component of the Rcs envelope stress response. RcsF exists in complexes with β-barrel proteins (OMPs) allowing it to adopt a transmembrane orientation with a lipidated N-terminal domain on the cell surface and a periplasmic C-terminal domain. Here we report that mutations that remove BamE or alter a residue in the RcsF trans-lumen domain specifically prevent assembly of the interlocked complexes without inactivating either RcsF or the OMP. Using these mutations we demonstrate that these RcsF/OMP complexes are required for sensing OM outer leaflet stress. Using mutations that alter the positively charged surface-exposed domain, we show that RcsF monitors lateral interactions between lipopolysaccharide (LPS) molecules. When these interactions are disrupted by cationic antimicrobial peptides, or by the loss of negatively charged phosphate groups on the LPS molecule, this information is transduced to the RcsF C-terminal signaling domain located in the periplasm to activate the stress response. DOI: http://dx.doi.org/10.7554/eLife.15276.001 PMID:27282389

  3. Informational basis of sensory adaptation: entropy and single-spike efficiency in rat barrel cortex.

    PubMed

    Adibi, Mehdi; Clifford, Colin W G; Arabzadeh, Ehsan

    2013-09-11

    We showed recently that exposure to whisker vibrations enhances coding efficiency in rat barrel cortex despite increasing correlations in variability (Adibi et al., 2013). Here, to understand how adaptation achieves this improvement in sensory representation, we decomposed the stimulus information carried in neuronal population activity into its fundamental components in the framework of information theory. In the context of sensory coding, these components are the entropy of the responses across the entire stimulus set (response entropy) and the entropy of the responses conditional on the stimulus (conditional response entropy). We found that adaptation decreased response entropy and conditional response entropy at both the level of single neurons and the pooled activity of neuronal populations. However, the net effect of adaptation was to increase the mutual information because the drop in the conditional entropy outweighed the drop in the response entropy. The information transmitted by a single spike also increased under adaptation. As population size increased, the information content of individual spikes declined but the relative improvement attributable to adaptation was maintained.

  4. A dynamic model for generating actuator specifications for small arms barrel active stabilization

    NASA Astrophysics Data System (ADS)

    Pathak, Anupam; Brei, Diann; Luntz, Jonathan; Lavigna, Chris

    2006-03-01

    Due to stresses encountered in combat, it is known that soldier marksmanship noticeably decreases regardless of prior training. Active stabilization systems in small arms have potential to address this problem to increase soldier survivability and mission effectiveness. The key to success is proper actuator design, but this is highly dependent on proper specification which is challenging due to the human/weapon interaction. This paper presents a generic analytical dynamic model which is capable of defining the necessary actuation specifications for a wide range of small arms platforms. The model is unique because it captures the human interface--shoulder and arm--that introduces the jitter disturbance in addition to the geometry, inertial properties and active stabilization stiffness of the small arms platform. Because no data to date is available for actual shooter-induced disturbance in field conditions, a method is given using the model to back-solve from measured shooting range variability data the disturbance amplitude information relative to the input source (arm or shoulder). As examples of the applicability of the model to various small arms systems, two different weapon systems were investigated: the M24 sniper weapon and the M16 assault rifle. In both cases, model based simulations provided valuable insight into impact on the actuation specifications (force, displacement, phase, frequency) due to the interplay of the human-weapon-active stabilization interface including the effect of shooter-disturbance frequency, disturbance location (shoulder vs. arm), and system parameters (stiffness, barrel rotation).

  5. Whisker row deprivation affects the flow of sensory information through rat barrel cortex.

    PubMed

    Jacob, Vincent; Mitani, Akinori; Toyoizumi, Taro; Fox, Kevin

    2017-01-01

    Whisker trimming causes substantial reorganization of neuronal response properties in barrel cortex. However, little is known about experience-dependent rerouting of sensory processing following sensory deprivation. To address this, we performed in vivo intracellular recordings from layers 2/3 (L2/3), layer 4 (L4), layer 5 regular-spiking (L5RS), and L5 intrinsically bursting (L5IB) neurons and measured their multiwhisker receptive field at the level of spiking activity, membrane potential, and synaptic conductance before and after sensory deprivation. We used Chernoff information to quantify the "sensory information" contained in the firing patterns of cells in response to spared and deprived whisker stimulation. In the control condition, information for flanking-row and same-row whiskers decreased in the order L4, L2/3, L5IB, L5RS. However, after whisker-row deprivation, spared flanking-row whisker information was reordered to L4, L5RS, L5IB, L2/3. Sensory information from the trimmed whiskers was reduced and delayed in L2/3 and L5IB neurons, whereas sensory information from spared whiskers was increased and advanced in L4 and L5RS neurons. Sensory information from spared whiskers was increased in L5IB neurons without a latency change. L5RS cells exhibited the largest changes in sensory information content through an atypical plasticity combining a significant decrease in spontaneous activity and an increase in a short-latency excitatory conductance.

  6. Baryon spectroscopy: Recent results from the Crystal Barrel/TAPS experiment at ELSA

    SciTech Connect

    Thoma, U.

    2010-08-05

    To understand the spectrum and the properties of baryon resonances, the CBELSA/TAPS experiment at ELSA investigates the photoproduction of single- and multi-meson final states off the nucleon. In the latter final states baryon cascades via Dp and Dh and also via higher mass baryon resonances are clearly observed. A partial wave analysis based on single and double meson photoproduction data as well as data from other reactions allows a first determination of resonance properties including partial decay widths of various N* and {Delta}* states. Those include also the decays into the different p{pi}{sup 0{pi}0} and p{pi}{sup 0{eta}} decay channels resulting partly in unexpected results. Recently not only single but also double polarisation experiments have been performed, which are absolutelly necessary to resolve ambiguities in the partial wave analyses (PWA) used to extract the resonances from the data; without the measurement of polarisation observables a model-independent PWA will not be possible. Polarisation observables have been investigated using linearly, circularly polarized or unpolarized photons impinging on an longitudinally polarized or unpolarized target. Given the angular coverage of the Crystal-Barrel/TAPS experiment this data cover almost the full angular range and phase space. This data will provide key information for the partial wave analyses and brings us one step closer towards the needed complete experiment.

  7. Man-In-The-Barrel. A Case of Cervical Spinal Cord Infarction and Review of the Literature

    PubMed Central

    Antelo, María José García; Facal, Teresa Lema; Sánchez, Tamara Pablos; Facal, María Soledad López; Nazabal, Eduardo Rubio

    2013-01-01

    Introduction: Man-in-the-barrel syndrome was initially observed in patients with signs of serious cerebral hypoperfusion, in the border zone of the anterior and medial cerebral artery, but other causes were communicated later. Methods: a healthy 43-year-old woman who showed intense cervical pain, irradiating over both shoulders and arms. Physical examination on admission highlighted notable brachial diparesis, tacto-algesic hypoesthesia of both arms and sensory level C4-D9. Results: cervical Magnetic Resonance Imaging (MRI) on admission revealed a hyperintense intramedullar lesion at C3-C7 level, due to a cervical cord infarction. Conclusions: our case reveals that conventional neurological consideration about the specific anatomical location of man-in-the-barrel syndrome in the brain should be extended to other locations such as the cervical column and not only the brain area. PMID:23407685

  8. Methods for Studying Interactions of Detergents and Lipids withα-Helical and β-Barrel Integral Membrane Proteins

    PubMed Central

    Hasan, S. Saif; Baniulis, Danas; Yamashita, Eiki; Zhalnina, Mariya V.; Zakharov, Stanislav D.; Stofleth, Jason T.; Cramer, William A.

    2014-01-01

    Methods for studying interactions of protein with lipids and detergents are described for representatives of two major classes of membrane proteins: (1) the α-helical heterooligomeric integral cytochrome b6f complex of oxygenic photosynthesis from cyanobacteria, and (2) the outer membrane β-barrel proteins BtuB and OmpF from Gram-negative Escherichia coli bacteria. Details are presented on the use of detergents for purification and crystallization of the b6f complex as well as a method for lipid exchange. The positions of detergent and lipid molecules, which define eight potential lipid-binding sites in the b6f complex, are described. Differences in detergent strategies for isolation and crystallization of β-barrel proteins relative to those for oligomeric helical membrane proteins are discussed, and purification and assessment of protein quality by circular dichroism (CD) is presented. PMID:24510648

  9. Total Maxillary Reconstruction Using a Double-Barreled and Double Skin Paddle Fibular Flap after Total Maxillectomy

    PubMed Central

    Sanchez, Gerardo; Lopez, Jaime; Perez, Adrian; Naal, Norberto

    2013-01-01

    Chondroblastomas are rare entities accounting for approximately 1% of all primary bone tumors. We describe a case of a 7-year-old girl with a giant chondroblastoma of the maxilla, treated with bilateral class III maxillectomy and reconstruction with a double-barreled and double skin paddle fibular free flap. We show evidence of an excellent aesthetic outcome at 6 months' follow up with no evidence of tumor recurrence. PMID:24286054

  10. Total maxillary reconstruction using a double-barreled and double skin paddle fibular flap after total maxillectomy.

    PubMed

    de la Parra, Miguel; Sanchez, Gerardo; Lopez, Jaime; Perez, Adrian; Naal, Norberto

    2013-11-01

    Chondroblastomas are rare entities accounting for approximately 1% of all primary bone tumors. We describe a case of a 7-year-old girl with a giant chondroblastoma of the maxilla, treated with bilateral class III maxillectomy and reconstruction with a double-barreled and double skin paddle fibular free flap. We show evidence of an excellent aesthetic outcome at 6 months' follow up with no evidence of tumor recurrence.

  11. Fear learning increases the number of polyribosomes associated with excitatory and inhibitory synapses in the barrel cortex.

    PubMed

    Jasinska, Malgorzata; Siucinska, Ewa; Jasek, Ewa; Litwin, Jan A; Pyza, Elzbieta; Kossut, Malgorzata

    2013-01-01

    Associative fear learning, resulting from whisker stimulation paired with application of a mild electric shock to the tail in a classical conditioning paradigm, changes the motor behavior of mice and modifies the cortical functional representation of sensory receptors involved in the conditioning. It also induces the formation of new inhibitory synapses on double-synapse spines of the cognate barrel hollows. We studied density and distribution of polyribosomes, the putative structural markers of enhanced synaptic activation, following conditioning. By analyzing serial sections of the barrel cortex by electron microscopy and stereology, we found that the density of polyribosomes was significantly increased in dendrites of the barrel activated during conditioning. The results revealed fear learning-induced increase in the density of polyribosomes associated with both excitatory and inhibitory synapses located on dendritic spines (in both single- and double-synapse spines) and only with the inhibitory synapses located on dendritic shafts. This effect was accompanied by a significant increase in the postsynaptic density area of the excitatory synapses on single-synapse spines and of the inhibitory synapses on double-synapse spines containing polyribosomes. The present results show that associative fear learning not only induces inhibitory synaptogenesis, as demonstrated in the previous studies, but also stimulates local protein synthesis and produces modifications of the synapses that indicate their potentiation.

  12. Effects of long-term sensory deprivation on asymmetric synapses in the whisker barrel field of the adult rat.

    PubMed

    Machín, Raquel; Pérez-Cejuela, César G; Bjugn, Roger; Avendaño, Carlos

    2006-08-30

    Whisker trimming deprives the cortical barrel field from the patterned sensory input that derives from active touch but leaves passive tactile signals unaltered. We have studied in the rat barrel field, by stereological procedures, the effects of a sustained period of unilateral deprivation by whisker clipping during adolescence and early adulthood on (1) the surface density (SV) of asymmetric synapses, as determined from measuring the presynaptic membrane specializations, and (2) the numerical density of asymmetric synaptic profiles (NA), classified according to their postsynaptic target and their apparent curvature. Compared to control rats, the procedure did not change the overall volume of the region, the volume fraction occupied by each cortical layer, or the volume fraction occupied by unmyelinated axons and boutons. However, the deprived barrel cortex displayed an increase in SV in layers I and II, and an increase in NA in layer I and in the cortex as a whole, mainly due to an increase in profiles with a convex shape. Layer IV was the least affected by the deprivation. These results point to a net increase, rather than a decrease, of excitatory synapses in the deprived cortex, which could result from a deprivation-induced decrease in the rate of normal synapse loss. This effect occurs specifically in superficial layers, more involved in intracortical and cortico-cortical, rather than thalamo-cortical, processing.

  13. transFold: a web server for predicting the structure and residue contacts of transmembrane beta-barrels.

    PubMed

    Waldispühl, J; Berger, Bonnie; Clote, Peter; Steyaert, Jean-Marc

    2006-07-01

    Transmembrane beta-barrel (TMB) proteins are embedded in the outer membrane of Gram-negative bacteria, mitochondria and chloroplasts. The cellular location and functional diversity of beta-barrel outer membrane proteins makes them an important protein class. At the present time, very few non-homologous TMB structures have been determined by X-ray diffraction because of the experimental difficulty encountered in crystallizing transmembrane (TM) proteins. The transFold web server uses pairwise inter-strand residue statistical potentials derived from globular (non-outer-membrane) proteins to predict the supersecondary structure of TMB. Unlike all previous approaches, transFold does not use machine learning methods such as hidden Markov models or neural networks; instead, transFold employs multi-tape S-attribute grammars to describe all potential conformations, and then applies dynamic programming to determine the global minimum energy supersecondary structure. The transFold web server not only predicts secondary structure and TMB topology, but is the only method which additionally predicts the side-chain orientation of transmembrane beta-strand residues, inter-strand residue contacts and TM beta-strand inclination with respect to the membrane. The program transFold currently outperforms all other methods for accuracy of beta-barrel structure prediction. Available at http://bioinformatics.bc.edu/clotelab/transFold.

  14. Ellagitannin content, volatile composition and sensory profile of wines from different countries matured in oak barrels subjected to different toasting methods.

    PubMed

    González-Centeno, M R; Chira, K; Teissedre, P-L

    2016-11-01

    Ellagitannins and aromatic compounds evolution in Cabernet Sauvignon wines macerated in oak barrels for a year was studied. Identical barrels with different toastings (medium toasting, medium toasting with watering, Noisette) were used in French, Italian and USA cellars. Ellagitannins increased by 84-96% with aging time, as did woody volatiles, by 86-91% in French wines and 23-35% in Italian wines, while fruity aroma compounds declined by 50-57% in the French and Italian wines over a 12-months period. Nevertheless, other behaviors and different kinetics rates for these compounds were observed depending on barrel toasting, wine matrix and their interactions. Perceived overall woody intensity was closely related to trans-whiskey lactone, guaiacol and vanillin, whereas astringency and bitterness were significantly linked to ellagitannins (p<0.05). This is the first study that evaluates the toasting effect on wines from different countries matured in the same oak barrels.

  15. Variations in oxygen and ellagitannins, and organoleptic properties of red wine aged in French oak barrels classified by a near infrared system.

    PubMed

    Michel, Julien; Albertin, Warren; Jourdes, Michael; Le Floch, Alexandra; Giordanengo, Thomas; Mourey, Nicolas; Teissedre, Pierre-Louis

    2016-08-01

    During wine aging in barrels, antioxidant molecules from wood, such as ellagitannins, are solubilized and react with wine molecules and oxygen. However, their concentrations are highly variable. Oxygen is an important factor, as it plays a role in wine parameters and organoleptic perceptions. Five barrel modalities were used; three polyphenol indices (IP), classified using the NIRS procedure, and three grain qualities. Barrels were equipped with windows to measure the oxygen using luminescence technology. The ellagitannin concentrations in the wine and its organoleptic properties were monitored. Oxygen concentrations decreased quickly during the first 8days of aging and this phenomenon was significantly more marked in barrels with a higher IP and medium grain. The ellagitannin concentrations were believed to be correlated with wood classification and oxygen consumption. Furthermore, the organoleptic properties were significantly impacted, as the wine with the lowest ellagitannin level was described as less astringent, bitter, woody, and smoky/toasty.

  16. A 3-dimensional trimeric β-barrel model for Chlamydia MOMP contains conserved and novel elements of Gram-negative bacterial porins.

    PubMed

    Feher, Victoria A; Randall, Arlo; Baldi, Pierre; Bush, Robin M; de la Maza, Luis M; Amaro, Rommie E

    2013-01-01

    Chlamydia trachomatis is the most prevalent cause of bacterial sexually transmitted diseases and the leading cause of preventable blindness worldwide. Global control of Chlamydia will best be achieved with a vaccine, a primary target for which is the major outer membrane protein, MOMP, which comprises ~60% of the outer membrane protein mass of this bacterium. In the absence of experimental structural information on MOMP, three previously published topology models presumed a16-stranded barrel architecture. Here, we use the latest β-barrel prediction algorithms, previous 2D topology modeling results, and comparative modeling methodology to build a 3D model based on the 16-stranded, trimeric assumption. We find that while a 3D MOMP model captures many structural hallmarks of a trimeric 16-stranded β-barrel porin, and is consistent with most of the experimental evidence for MOMP, MOMP residues 320-334 cannot be modeled as β-strands that span the entire membrane, as is consistently observed in published 16-stranded β-barrel crystal structures. Given the ambiguous results for β-strand delineation found in this study, recent publications of membrane β-barrel structures breaking with the canonical rule for an even number of β-strands, findings of β-barrels with strand-exchanged oligomeric conformations, and alternate folds dependent upon the lifecycle of the bacterium, we suggest that although the MOMP porin structure incorporates canonical 16-stranded conformations, it may have novel oligomeric or dynamic structural changes accounting for the discrepancies observed.

  17. NEW GUN CAPABILITY WITH INTERCHANGABLE BARRELS TO INVESTIGATE LOW VELOCITY IMPACT REGIMES AT THE LAWRENCE LIVERMORE NATIONAL LABORATORY HIGH EXPLOSIVES APPLICATIONS FACILITY

    SciTech Connect

    Vandersall, K S; Behn, A; Gresshoff, M; Jr., L F; Chiao, P I

    2009-09-16

    A new gas gun capability is being activated at Lawrence Livermore National Laboratories located in the High Explosives Applications Facility (HEAF). The single stage light gas (dry air, nitrogen, or helium) gun has interchangeable barrels ranging from 25.4 mm to 76.2 mm in diameter with 1.8 meters in length and is being fabricated by Physics Applications, Inc. Because it is being used for safety studies involving explosives, the gun is planned for operation inside a large enclosed firing tank, with typical velocities planned in the range of 10-300 m/s. Three applications planned for this gun include: low velocity impact of detonator or detonator/booster assemblies with various projectile shapes, the Steven Impact test that involves impact initiation of a cased explosive target, and the Taylor impact test using a cylindrical explosive sample impacted onto a rigid anvil for fracture studies of energetic materials. A highlight of the gun features, outline on work in progress for implementing this capability, and discussion of the planned areas of research will be included.

  18. Production summary for extended barrel module fabrication at Argonne for the ATLAS tile calorimeter.

    SciTech Connect

    Guarino, V.; Hill, N.; Petereit, E.; Skrzecz, F.; Wood, K.; Proudfoot, J.; Anderson, S.; Caird, A.; Keyser, C.; Kocenko, L.; Matijas, Z.; Nephew, T.; Stanek, R.; Franchini, F.; High Energy Physics

    2007-11-14

    The Tile Calorimeter is one of the main hadronic calorimeters to be used in the ATLAS experiment at CERN [1,2]. It is a steel/scintillator sampling calorimeter which is built by stacking 64 segments in azimuth and 3 separate cylinders to provide a total structure whose length is approximately 12m and whose diameter is a little over 8.4m. It has a total weight of about 2630 metric tons. Important features of this calorimeter are: A minimum gap (1.5mm) between modules in azimuth; Pockets in the structure to hold the scintillator tiles; Recessed channels at the edges of the module into which the readout fibers will sit; and Holes in the structure through which a radioactive source will pass. The mechanical structure for one of the 3 calorimeter sections, the Extended Barrel (EBA) was constructed at Argonne. A schematic of the calorimeter sampling structure and the layout of one of the 64 segments, termed a module, are shown in figure 1. Each module comprises mechanically of a precision machined, structural girder to which 10 submodules are bolted. One of these submodules, the ITC, has a customized shape to accommodate services for other detector elements. Each submodule weighs 850Kg and the assembled mechanical structure of the module weighs approximately 9000Kg (a fully instrumented Extended Barrel modules weighs {approx}9600Kg). A crucial issue for the tile calorimeter assembly is the minimization of the un-instrumented gap between modules when they are stacked on top of each other during final assembly. The design goal was originally 1mm gap which was eventually relaxed to 1.5mm following a careful evaluation of all tolerances in the construction and assembly process as shown in figure 2 [3]. Submodules for this assembly were produced at 4 locations [4] using tooling and procedures which were largely identical [5]. An important issue was the height of each submodule on the stacking fixture on which they were fabricated as this defines the length along the girder

  19. The β-Barrel Outer Membrane Protein Assembly Complex of Neisseria meningitidis▿

    PubMed Central

    Volokhina, Elena B.; Beckers, Frank; Tommassen, Jan; Bos, Martine P.

    2009-01-01

    The evolutionarily conserved protein Omp85 is required for outer membrane protein (OMP) assembly in gram-negative bacteria and in mitochondria. Its Escherichia coli homolog, designated BamA, functions with four accessory lipoproteins, BamB, BamC, BamD, and BamE, together forming the β-barrel assembly machinery (Bam). Here, we addressed the composition of this machinery and the function of its components in Neisseria meningitidis, a model organism for outer membrane biogenesis studies. Analysis of genome sequences revealed homologs of BamC, BamD (previously described as ComL), and BamE and a second BamE homolog, Mlp. No homolog of BamB was found. As in E. coli, ComL/BamD appeared essential for viability and for OMP assembly, and it could not be replaced by its E. coli homolog. BamE was not essential but was found to contribute to the efficiency of OMP assembly and to the maintenance of OM integrity. A bamC mutant showed only marginal OMP assembly defects, but the impossibility of creating a bamC bamE double mutant further indicated the function of BamC in OMP assembly. An mlp mutant was unaffected in OMP assembly. The results of copurification assays demonstrated the association of BamC, ComL, and BamE with Omp85. Semi-native gel electrophoresis identified the RmpM protein as an additional component of the Omp85 complex, which was confirmed in copurification assays. RmpM was not required for OMP folding but stabilized OMP complexes. Thus, the Bam complex in N. meningitidis consists of Omp85/BamA plus RmpM, BamC, ComL/BamD, and BamE, of which ComL/BamD and BamE appear to be the most important accessory components for OMP assembly. PMID:19767435

  20. Transcriptional activity of the giant barrel sponge, Xestospongia muta Holobiont: molecular evidence for metabolic interchange

    PubMed Central

    Fiore, Cara L.; Labrie, Micheline; Jarett, Jessica K.; Lesser, Michael P.

    2015-01-01

    Compared to our understanding of the taxonomic composition of the symbiotic microbes in marine sponges, the functional diversity of these symbionts is largely unknown. Furthermore, the application of genomic, transcriptomic, and proteomic techniques to functional questions on sponge host-symbiont interactions is in its infancy. In this study, we generated a transcriptome for the host and a metatranscriptome of its microbial symbionts for the giant barrel sponge, Xestospongia muta, from the Caribbean. In combination with a gene-specific approach, our goals were to (1) characterize genetic evidence for nitrogen cycling in X. muta, an important limiting nutrient on coral reefs (2) identify which prokaryotic symbiont lineages are metabolically active and, (3) characterize the metabolic potential of the prokaryotic community. Xestospongia muta expresses genes from multiple nitrogen transformation pathways that when combined with the abundance of this sponge, and previous data on dissolved inorganic nitrogen fluxes, shows that this sponge is an important contributor to nitrogen cycling biogeochemistry on coral reefs. Additionally, we observed significant differences in gene expression of the archaeal amoA gene, which is involved in ammonia oxidation, between coral reef locations consistent with differences in the fluxes of dissolved inorganic nitrogen previously reported. In regards to symbiont metabolic potential, the genes in the biosynthetic pathways of several amino acids were present in the prokaryotic metatranscriptome dataset but in the host-derived transcripts only the catabolic reactions for these amino acids were present. A similar pattern was observed for the B vitamins (riboflavin, biotin, thiamin, cobalamin). These results expand our understanding of biogeochemical cycling in sponges, and the metabolic interchange highlighted here advances the field of symbiont physiology by elucidating specific metabolic pathways where there is high potential for host

  1. Volcanic stratigraphy of the Barrel Springs--Wild Cherry Formations, Davis Mountains, Trans-Pecos Texas

    SciTech Connect

    Parker, D.F. . Dept. Geology); Henry, C.D. . Bureau of Economic Geology); Kunk, M.J. )

    1993-02-01

    Detailed mapping, stratigraphy, [sup 40]Ar/[sup 39]Ar ages, and geochemistry allow, for the first time, a coherent volcanic history of the Barrel Springs--Wild Cherry (BS-WC) units, the most widespread of the Davis Mountains volcanic field (DMVF). These units erupted dominantly from the [approximately] 20 km-diameter Paradise Mountain caldera (PMC), in the west-central DMVF, where thick, locally silicified and kaolinized intracaldera tuffs and interbedded lavas were resurgently domed by an 8 x 5-km-diameter syenitic intrusion. BS-WC units, all rhyolites, consist dominantly of a lower, moderately porphyritic ash-flow tuff; a petrographically similar, middle ash-flow tuff; and an upper group of voluminous, abundantly porphyritic lavas. The lower ash-flow tuff is strongly rheomorphic throughout its occurrence. The middle ash-flow is also rheomorphic in thick outcrops near the PMC but not in thin ([<=]10m), distal outcrops. These three units are interbedded with lavas lithologically similar to the tuffs near the PMC and with volcaniclastic sedimentary rocks in more distal area. The two ash-flow tuffs are separated by strongly porphyritic trachyte lavas of the Mount Locke Formation in the vicinity of the PMC. Sources and extents of individual flows of the upper lavas have not been positively identified. [sup 40]Ar/[sup 39]Ar ages of alkali feldspar phenocrysts from thirteen samples constrain most BS-WC to a 300 ka span. The lower tuff erupted about 35.6 Ma. The middle tuff and part of the voluminous lava package erupted at 35.3 Ma. Ages of two lavas are 35.1 Ma, which suggests prolonged eruption. Correlations based on lithology and age relations are supplemented by trace element and mineral studies that confirm close geochemical affinities.

  2. Structural coalescence underlies the aggregation propensity of a β-barrel protein motif

    PubMed Central

    Angelani, Carla R.; Caramelo, Julio J.; Curto, Lucrecia M.; Delfino, José M.

    2017-01-01

    A clear understanding of the structural foundations underlying protein aggregation is an elusive goal of central biomedical importance. A step toward this aim is exemplified by the β-barrel motif represented by the intestinal fatty acid binding protein (IFABP) and two abridged all-β sheet forms (Δ98Δ and Δ78Δ). At odds with the established notion that a perturbation of the native fold should necessarily favor a buildup of intermediate forms with an enhanced tendency to aggregate, the intrinsic stability (ΔG°H2O) of these proteins does not bear a straightforward correlation with their trifluoroethanol (TFE)-induced aggregation propensity. In view of this fact, we found it more insightful to delve into the connection between structure and stability under sub-aggregating conditions (10% TFE). In the absence of the co-solvent, the abridged variants display a common native-like region decorated with a disordered C-terminal stretch. Upon TFE addition, an increase in secondary structure content is observed, assimilating them to the parent protein. In this sense, TFE perturbs a common native like region while exerting a global compaction effect. Importantly, in all cases, fatty acid binding function is preserved. Interestingly, energetic as well as structural diversity in aqueous solution evolves into a common conformational ensemble more akin in stability. These facts reconcile apparent paradoxical findings related to stability and rates of aggregation. This scenario likely mimics the accrual of aggregation-prone species in the population, an early critical event for the development of fibrillation. PMID:28187186

  3. Structural coalescence underlies the aggregation propensity of a β-barrel protein motif.

    PubMed

    Angelani, Carla R; Caramelo, Julio J; Curto, Lucrecia M; Delfino, José M

    2017-01-01

    A clear understanding of the structural foundations underlying protein aggregation is an elusive goal of central biomedical importance. A step toward this aim is exemplified by the β-barrel motif represented by the intestinal fatty acid binding protein (IFABP) and two abridged all-β sheet forms (Δ98Δ and Δ78Δ). At odds with the established notion that a perturbation of the native fold should necessarily favor a buildup of intermediate forms with an enhanced tendency to aggregate, the intrinsic stability (ΔG°H2O) of these proteins does not bear a straightforward correlation with their trifluoroethanol (TFE)-induced aggregation propensity. In view of this fact, we found it more insightful to delve into the connection between structure and stability under sub-aggregating conditions (10% TFE). In the absence of the co-solvent, the abridged variants display a common native-like region decorated with a disordered C-terminal stretch. Upon TFE addition, an increase in secondary structure content is observed, assimilating them to the parent protein. In this sense, TFE perturbs a common native like region while exerting a global compaction effect. Importantly, in all cases, fatty acid binding function is preserved. Interestingly, energetic as well as structural diversity in aqueous solution evolves into a common conformational ensemble more akin in stability. These facts reconcile apparent paradoxical findings related to stability and rates of aggregation. This scenario likely mimics the accrual of aggregation-prone species in the population, an early critical event for the development of fibrillation.

  4. Eukaryote-wide sequence analysis of mitochondrial β-barrel outer membrane proteins

    PubMed Central

    2011-01-01

    Background The outer membranes of mitochondria are thought to be homologous to the outer membranes of Gram negative bacteria, which contain 100's of distinct families of β-barrel membrane proteins (BOMPs) often forming channels for transport of nutrients or drugs. However, only four families of mitochondrial BOMPs (MBOMPs) have been confirmed to date. Although estimates as high as 100 have been made in the past, the number of yet undiscovered MBOMPs is an open question. Fortunately, the recent discovery of a membrane integration signal (the β-signal) for MBOMPs gave us an opportunity to look for undiscovered MBOMPs. Results We present the results of a comprehensive survey of eukaryotic protein sequences intended to identify new MBOMPs. Our search employs recent results on β-signals as well as structural information and a novel BOMP predictor trained on both bacterial and mitochondrial BOMPs. Our principal finding is circumstantial evidence suggesting that few MBOMPs remain to be discovered, if one assumes that, like known MBOMPs, novel MBOMPs will be monomeric and β-signal dependent. In addition to this, our analysis of MBOMP homologs reveals some exceptions to the current model of the β-signal, but confirms its consistent presence in the C-terminal region of MBOMP proteins. We also report a β-signal independent search for MBOMPs against the yeast and Arabidopsis proteomes. We find no good candidates MBOMPs in yeast but the Arabidopsis results are less conclusive. Conclusions Our results suggest there are no remaining MBOMPs left to discover in yeast; and if one assumes all MBOMPs are β-signal dependent, few MBOMP families remain undiscovered in any sequenced organism. PMID:21272379

  5. Morphological Characteristics of Electrophysiologically Characterized Layer Vb Pyramidal Cells in Rat Barrel Cortex

    PubMed Central

    Loucif, Alexandre J. C.; Schubert, Dirk; Möck, Martin

    2016-01-01

    Layer Vb pyramidal cells are the major output neurons of the neocortex and transmit the outcome of cortical columnar signal processing to distant target areas. At the same time they contribute to local tactile information processing by emitting recurrent axonal collaterals into the columnar microcircuitry. It is, however, not known how exactly the two types of pyramidal cells, called slender-tufted and thick-tufted, contribute to the local circuitry. Here, we investigated in the rat barrel cortex the detailed quantitative morphology of biocytin-filled layer Vb pyramidal cells in vitro, which were characterized for their intrinsic electrophysiology with special emphasis on their action potential firing pattern. Since we stained the same slices for cytochrome oxidase, we could also perform layer- and column-related analyses. Our results suggest that in layer Vb the unambiguous action potential firing patterns "regular spiking (RS)" and "repetitive burst spiking (RB)" (previously called intrinsically burst spiking) correlate well with a distinct morphology. RS pyramidal cells are somatodendritically of the slender-tufted type and possess numerous local intralaminar and intracolumnar axonal collaterals, mostly reaching layer I. By contrast, their transcolumnar projections are less well developed. The RB pyramidal cells are somatodendritically of the thick-tufted type and show only relatively sparse local axonal collaterals, which are preferentially emitted as long horizontal or oblique infragranular collaterals. However, contrary to many previous slice studies, a substantial number of these neurons also showed axonal collaterals reaching layer I. Thus, electrophysiologically defined pyramidal cells of layer Vb show an input and output pattern which suggests RS cells to be more "locally segregating" signal processors whereas RB cells seem to act more on a "global integrative" scale. PMID:27706253

  6. Thermal Energy Exchange Model and Water Loss of a Barrel Cactus, Ferocactus acanthodes.

    PubMed

    Lewis, D A; Nobel, P S

    1977-10-01

    The influences of various diurnal stomatal opening patterns, spines, and ribs on the stem surface temperature and water economy of a CAM succulent, the barrel cactus Ferocactus acanthodes, were examined using an energy budget model. To incorporate energy exchanges by shortwave and longwave irradiation, latent heat, conduction, and convection as well as the heat storage in the massive stem, the plant was subdivided into over 100 internal and external regions in the model. This enabled the average surface temperature to be predicted within 1 C of the measured temperature for both winter and summer days.Reducing the stem water vapor conductance from the values observed in the field to zero caused the average daily stem surface temperature to increase only 0.7 C for a winter day and 0.3 C for a summer day. Thus, latent heat loss does not substantially reduce stem temperature. Although the surface temperatures averaged 18 C warmer for the summer day than for the winter day for a plant 41 cm tall, the temperature dependence of stomatal opening caused the simulated nighttime water loss rates to be about the same for the 2 days.Spines moderated the amplitude of the diurnal temperature changes of the stem surface, since the daily variation was 17 C for the winter day and 25 C for the summer day with spines compared with 23 C and 41 C, respectively, in their simulated absence. Ribs reduced the daytime temperature rise by providing 54% more area for convective heat loss than for a smooth circumscribing surface. In a simulation where both spines and ribs were eliminated, the daytime average surface temperature rose by 5 C.

  7. Thermal Energy Exchange Model and Water Loss of a Barrel Cactus, Ferocactus acanthodes1

    PubMed Central

    Lewis, Donald A.; Nobel, Park S.

    1977-01-01

    The influences of various diurnal stomatal opening patterns, spines, and ribs on the stem surface temperature and water economy of a CAM succulent, the barrel cactus Ferocactus acanthodes, were examined using an energy budget model. To incorporate energy exchanges by shortwave and longwave irradiation, latent heat, conduction, and convection as well as the heat storage in the massive stem, the plant was subdivided into over 100 internal and external regions in the model. This enabled the average surface temperature to be predicted within 1 C of the measured temperature for both winter and summer days. Reducing the stem water vapor conductance from the values observed in the field to zero caused the average daily stem surface temperature to increase only 0.7 C for a winter day and 0.3 C for a summer day. Thus, latent heat loss does not substantially reduce stem temperature. Although the surface temperatures averaged 18 C warmer for the summer day than for the winter day for a plant 41 cm tall, the temperature dependence of stomatal opening caused the simulated nighttime water loss rates to be about the same for the 2 days. Spines moderated the amplitude of the diurnal temperature changes of the stem surface, since the daily variation was 17 C for the winter day and 25 C for the summer day with spines compared with 23 C and 41 C, respectively, in their simulated absence. Ribs reduced the daytime temperature rise by providing 54% more area for convective heat loss than for a smooth circumscribing surface. In a simulation where both spines and ribs were eliminated, the daytime average surface temperature rose by 5 C. PMID:16660148

  8. Identifying the structural boundaries of independent folding domains in the alpha subunit of tryptophan synthase, a beta/alpha barrel protein.

    PubMed Central

    Zitzewitz, J. A.; Gualfetti, P. J.; Perkons, I. A.; Wasta, S. A.; Matthews, C. R.

    1999-01-01

    Two equilibrium intermediates have previously been observed in the urea denaturation of the alpha subunit of tryptophan synthase (alphaTS) from Escherichia coli, an eight-stranded beta/alpha barrel protein. In the current study, a series of amino-terminal fragments were characterized to probe the elementary folding units that may be in part responsible for this complex behavior. Stop-codon mutagenesis was used to produce eight fragments ranging in size from 105-214 residues and containing incremental elements of secondary structure. Equilibrium studies by circular dichroism indicate that all of these fragments are capable of adopting secondary structure. All except for the shortest fragment fold cooperatively. The addition of the fourth, sixth, and eighth beta-strands leads to distinct increases in structure, cooperativity, and/or stability, suggesting that folding involves the modular assembly of betaalphabeta supersecondary structural elements. One-dimensional NMR titrations at high concentrations of urea, probing the environment around His92, were also performed to test for the presence of residual structure in the fragments. All fragments that contained the first four betaalpha units of structure exhibited a cooperative unfolding transition at high concentrations of urea with significant but reduced stability relative to the full-length protein. These results suggest that the residual structure in alphaTS requires the participation of hydrophobic residues in multiple beta-strands that span the entire sequence. PMID:10386870

  9. Whisker row deprivation affects the flow of sensory information through rat barrel cortex

    PubMed Central

    Jacob, Vincent; Mitani, Akinori; Toyoizumi, Taro

    2016-01-01

    Whisker trimming causes substantial reorganization of neuronal response properties in barrel cortex. However, little is known about experience-dependent rerouting of sensory processing following sensory deprivation. To address this, we performed in vivo intracellular recordings from layers 2/3 (L2/3), layer 4 (L4), layer 5 regular-spiking (L5RS), and L5 intrinsically bursting (L5IB) neurons and measured their multiwhisker receptive field at the level of spiking activity, membrane potential, and synaptic conductance before and after sensory deprivation. We used Chernoff information to quantify the “sensory information” contained in the firing patterns of cells in response to spared and deprived whisker stimulation. In the control condition, information for flanking-row and same-row whiskers decreased in the order L4, L2/3, L5IB, L5RS. However, after whisker-row deprivation, spared flanking-row whisker information was reordered to L4, L5RS, L5IB, L2/3. Sensory information from the trimmed whiskers was reduced and delayed in L2/3 and L5IB neurons, whereas sensory information from spared whiskers was increased and advanced in L4 and L5RS neurons. Sensory information from spared whiskers was increased in L5IB neurons without a latency change. L5RS cells exhibited the largest changes in sensory information content through an atypical plasticity combining a significant decrease in spontaneous activity and an increase in a short-latency excitatory conductance. NEW & NOTEWORTHY Sensory cortical plasticity is usually quantified by changes in evoked firing rate. In this study we quantified plasticity by changes in sensory detection performance using Chernoff information and receiver operating characteristic analysis. We found that whisker deprivation causes a change in information flow within the cortical layers and that layer 5 regular-spiking cells, despite showing only a small potentiation of short-latency input, show the greatest increase in information content for

  10. Barrel organ of plate tectonics - a new tool for outreach and education

    NASA Astrophysics Data System (ADS)

    Broz, Petr; Machek, Matěj; Šorm, Zdar

    2016-04-01

    Plate tectonics is the major geological concept to explain dynamics and structure of Earth's outer shell, the lithosphere. In the plate tectonic theory processes in the Earth lithosphere and its dynamics is driven by the relative motion and interaction of lithospheric plates. Geologically most active regions on Earth often correlate with the lithospheric plate boundaries. Thus for explaining the earth surface evolution, mountain building, volcanism and earthquake origin it is important to understand processes at the plate boundaries. However these processes associated with plate tectonics usually require significant period of time to take effects, therefore, their entire cycles cannot be directly observed in the nature by humans. This makes a challenge for scientists studying these processes, but also for teachers and popularizers trying to explain them to students and to the general public. Therefore, to overcome this problem, we developed a mechanical model of plate tectonics enabling demonstration of most important processes associated with plate tectonics in real time. The mechanical model is a wooden box, more specifically a special type of barrel organ, with hand painted backdrops in the front side. These backdrops are divided into several components representing geodynamic processes associated with plate tectonics, specifically convective currents occurring in the mantle, sea-floor spreading, a subduction of the oceanic crust under the continental crust, partial melting and volcanism associated with subduction, a formation of magmatic stripes, an ascent of mantle plume throughout the mantle, a volcanic activity associated with hot spots, and a formation and degradation of volcanic islands on moving lithospheric plate. All components are set in motion by a handle controlled by a human operator, and the scene is illuminated with colored lights controlled automatically by an electric device embedded in the box. Operation of the model may be seen on www

  11. Characterization of a novel β-barrel protein (AtOM47) from the mitochondrial outer membrane of Arabidopsis thaliana

    PubMed Central

    Li, Lu; Kubiszewski-Jakubiak, Szymon; Radomiljac, Jordan; Wang, Yan; Law, Simon R.; Keech, Olivier; Narsai, Reena; Berkowitz, Oliver; Duncan, Owen; Murcha, Monika W.; Whelan, James

    2016-01-01

    In plant cells, mitochondria are major providers of energy and building blocks for growth and development as well as abiotic and biotic stress responses. They are encircled by two lipid membranes containing proteins that control mitochondrial function through the import of macromolecules and metabolites. Characterization of a novel β-barrel protein, OUTER MEMBRANE PROTEIN 47 (OM47), unique to the green lineage and related to the voltage-dependent anion channel (VDAC) protein family, showed that OM47 can complement a VDAC mutant in yeast. Mutation of OM47 in Arabidopsis thaliana by T-DNA insertion had no effect on the import of proteins, such as the β-barrel proteins translocase of the outer membrane 40 (TOM40) or sorting and assembly machinery 50 (SAM50), into mitochondria. Molecular and physiological analyses revealed a delay in chlorophyll breakdown, higher levels of starch, and a delay in the induction of senescence marker genes in the mutant lines. While there was a reduction of >90% in OM47 protein in mitochondria isolated from 3-week-old om47 mutants, in mitochondria isolated from 8-week-old plants OM47 levels were similar to that of the wild type. This recovery was achieved by an up-regulation of OM47 transcript abundance in the mutants. Combined, these results highlight a role in leaf senescence for this plant-specific β-barrel protein, probably mediating the recovery and recycling of chloroplast breakdown products by transporting metabolic intermediates into and out of mitochondria. PMID:27811077

  12. Apparatus and method for quantitative assay of samples of transuranic waste contained in barrels in the presence of matrix material

    DOEpatents

    Caldwell, J.T.; Herrera, G.C.; Hastings, R.D.; Shunk, E.R.; Kunz, W.E.

    1987-08-28

    Apparatus and method for performing corrections for matrix material effects on the neutron measurements generated from analysis of transuranic waste drums using the differential-dieaway technique. By measuring the absorption index and the moderator index for a particular drum, correction factors can be determined for the effects of matrix materials on the ''observed'' quantity of fissile and fertile material present therein in order to determine the actual assays thereof. A barrel flux monitor is introduced into the measurement chamber to accomplish these measurements as a new contribution to the differential-dieaway technology. 9 figs.

  13. Genetic analysis of posterior medial barrel subfield (PMBSF) size in somatosensory cortex (SI) in recombinant inbred strains of mice

    PubMed Central

    Jan, Taha A; Lu, Lu; Li, Cheng-Xiang; Williams, Robert W; Waters, Robert S

    2008-01-01

    Background Quantitative trait locus (QTL) mapping is an important tool for identifying potential candidate genes linked to complex traits. QTL mapping has been used to identify genes associated with cytoarchitecture, cell number, brain size, and brain volume. Previously, QTL mapping was utilized to examine variation of barrel field size in the somatosensory cortex in a limited number of recombinant inbred (RI) strains of mice. In order to further elucidate the underlying natural variation in mouse primary somatosensory cortex, we measured the size of the posterior medial barrel subfield (PMBSF), associated with the representation of the large mystacial vibrissae, in an expanded sample set that included 42 BXD RI strains, two parental strains (C57BL/6J and DBA/2J), and one F1 strain (B6D2F1). Cytochrome oxidase labeling was used to visualize barrels within the PMBSF. Results We observed a 33% difference between the largest and smallest BXD RI strains with continuous variation in-between. Using QTL linkage analysis from WebQTL, we generated linkage maps of raw total PMBSF and brain weight adjusted total PMBSF areas. After removing the effects of brain weight, we detected a suggestive QTL (likelihood ratio statistic [LRS]: 14.20) on the proximal arm of chromosome 4. Candidate genes under the suggestive QTL peak for PMBSF area were selected based on the number of single nucleotide polymorphisms (SNPs) present and the biological relevance of each gene. Among the candidate genes are Car8 and Rab2. More importantly, mRNA expression profiles obtained using GeneNetwork indicated a strong correlation between total PMBSF area and two genes (Adcy1 and Gap43) known to be important in mouse cortex development. GAP43 has been shown to be critical during neurodevelopment of the somatosensory cortex, while knockout Adcy1 mice have disrupted barrel field patterns. Conclusion We detected a novel suggestive QTL on chromosome 4 that is linked to PMBSF size. The present study is an

  14. Our Treatment Approaches in Severe Maxillofacial Injuries Occurring After Failed Suicide Attempts Using Long-Barreled Guns.

    PubMed

    Kucuker, Ismail; Şimşek, Tekin; Keles, Musa Kemal; Yosma, Engin; Aksakal, Ibrahim Alper; Demir, Ahmet

    2016-03-01

    Maxillofacial traumas with long-barreled guns may sometimes cause catastrophic results by means of smashing in facial structures. In these patients, reconstruction strategies of both fragmented/lost soft and hard tissues still remain controversial. In their clinic, the authors treated 5 patients with severely injured face after failed suicide attempt between 2008 and 2013. In this study, the authors aimed to present their clinical experiences on these severely injured maxillofacial gunshot traumas and offer a treatment algorithm to gain a result as possible as satisfactory in terms of functionality and appearance.

  15. Associations of Unilateral Whisker and Olfactory Signals Induce Synapse Formation and Memory Cell Recruitment in Bilateral Barrel Cortices: Cellular Mechanism for Unilateral Training Toward Bilateral Memory

    PubMed Central

    Gao, Zilong; Chen, Lei; Fan, Ruicheng; Lu, Wei; Wang, Dangui; Cui, Shan; Huang, Li; Zhao, Shidi; Guan, Sudong; Zhu, Yan; Wang, Jin-Hui

    2016-01-01

    Somatosensory signals and operative skills learned by unilateral limbs can be retrieved bilaterally. In terms of cellular mechanism underlying this unilateral learning toward bilateral memory, we hypothesized that associative memory cells in bilateral cortices and synapse innervations between them were produced. In the examination of this hypothesis, we have observed that paired unilateral whisker and odor stimulations led to odorant-induced whisker motions in bilateral sides, which were attenuated by inhibiting the activity of barrel cortices. In the mice that showed bilateral cross-modal responses, the neurons in both sides of barrel cortices became to encode this new odor signal alongside the innate whisker signal. Axon projections and synapse formations from the barrel cortex, which was co-activated with the piriform cortex, toward its contralateral barrel cortex (CBC) were upregulated. Glutamatergic synaptic transmission in bilateral barrel cortices was upregulated and GABAergic synaptic transmission was downregulated. The associative activations of the sensory cortices facilitate new axon projection, glutamatergic synapse formation and GABAergic synapse downregulation, which drive the neurons to be recruited as associative memory cells in the bilateral cortices. Our data reveal the productions of associative memory cells and synapse innervations in bilateral sensory cortices for unilateral training toward bilateral memory. PMID:28018178

  16. Mitochondrial-bacterial hybrids of BamA/Tob55 suggest variable requirements for the membrane integration of β-barrel proteins

    PubMed Central

    Pfitzner, Anna-Katharina; Steblau, Nadja; Ulrich, Thomas; Oberhettinger, Philipp; Autenrieth, Ingo B.; Schütz, Monika; Rapaport, Doron

    2016-01-01

    β-Barrel proteins are found in the outer membrane (OM) of Gram-negative bacteria, chloroplasts and mitochondria. The assembly of these proteins into the corresponding OM is facilitated by a dedicated protein complex that contains a central conserved β-barrel protein termed BamA in bacteria and Tob55/Sam50 in mitochondria. BamA and Tob55 consist of a membrane-integral C-terminal domain that forms a β-barrel pore and a soluble N-terminal portion comprised of one (in Tob55) or five (in BamA) polypeptide transport-associated (POTRA) domains. Currently the functional significance of this difference and whether the homology between BamA and Tob55 can allow them to replace each other are unclear. To address these issues we constructed hybrid Tob55/BamA proteins with differently configured N-terminal POTRA domains. We observed that constructs harboring a heterologous C-terminal domain could not functionally replace the bacterial BamA or the mitochondrial Tob55 demonstrating species-specific requirements. Interestingly, the various hybrid proteins in combination with the bacterial chaperones Skp or SurA supported to a variable extent the assembly of bacterial β-barrel proteins into the mitochondrial OM. Collectively, our findings suggest that the membrane assembly of various β-barrel proteins depends to a different extent on POTRA domains and periplasmic chaperones. PMID:27982054

  17. Revisiting the membrane interaction mechanism of a membrane-damaging β-barrel pore-forming toxin Vibrio cholerae cytolysin.

    PubMed

    Rai, Anand Kumar; Chattopadhyay, Kausik

    2015-09-01

    Vibrio cholerae cytolysin (VCC) permeabilizes target cell membranes by forming transmembrane oligomeric β-barrel pores. VCC has been shown to associate with the target membranes via amphipathicity-driven spontaneous partitioning into the membrane environment. More specific interaction(s) of VCC with the membrane components have also been documented. In particular, specific binding of VCC with the membrane lipid components is believed to play a crucial role in determining the efficacy of the pore-formation process. However, the structural basis and the functional implications of the VCC interaction with the membrane lipids remain unclear. Here we show that the distinct loop sequences within the membrane-proximal region of VCC play critical roles to determine the functional interactions of the toxin with the membrane lipids. Alterations of the loop sequences via structure-guided mutagenesis allow amphipathicity-driven partitioning of VCC to the membrane lipid bilayer. Alterations of the loop sequences, however, block specific interactions of VCC with the membrane lipids and abort the oligomerization, membrane insertion, pore-formation and cytotoxic activity of the toxin. Present study identifies the structural signatures in VCC implicated for its functional interactions with the membrane lipid components, a process that presumably acts to drive the subsequent steps of the oligomeric β-barrel pore-formation and cytotoxic responses.

  18. [Confusing injury findings in a suicidal gunshot fired to the chest from a carbine with a sawed-off barrel].

    PubMed

    Perdekamp, Markus Grosse; Bohnert, Michael; Braunwarth, Roland; Pollak, Stefan

    2006-01-01

    The stellate bullet entrance wound is one of the facultative features of a contact shot. For the formation of a star-shaped wound two factors are of special importance: first, an extensive bony support underlying the skin in the entrance region, and second, a strong propellant charge of the cartridge fired. Contact shots to the precordial region usually do not cause stellate entrance wounds, even if high-powered rifle ammunition is used. In the reported case, an injury pattern was observed that was not in line with normal findings and seemed confusing at first. Following a suicidal gunshot to the chest from a sawed-off carbine 98a (cal. 8 x 57 Js), a 4.5 cm wide, gaping bullet entrance wound with radiating tears was found. Instead of the usual pocket, the anterior thoracic wall showed a fist-sized area of destruction with extensive undermining of the subcutis. Not far from the entrance hole, a rib fragment had become displaced retrogradely thus perforating the skin from the inside out. The unusual pattern of findings could be explained by the fact that the barrel had been sawed off: as a result of this manipulation, a considerable part of the propellant charge had been converted outside the barrel, i.e. in the initial section of the bullet path.

  19. Feedforward motor information enhances somatosensory responses and sharpens angular tuning of rat S1 barrel cortex neurons

    PubMed Central

    Khateb, Mohamed; Schiller, Jackie; Schiller, Yitzhak

    2017-01-01

    The primary vibrissae motor cortex (vM1) is responsible for generating whisking movements. In parallel, vM1 also sends information directly to the sensory barrel cortex (vS1). In this study, we investigated the effects of vM1 activation on processing of vibrissae sensory information in vS1 of the rat. To dissociate the vibrissae sensory-motor loop, we optogenetically activated vM1 and independently passively stimulated principal vibrissae. Optogenetic activation of vM1 supra-linearly amplified the response of vS1 neurons to passive vibrissa stimulation in all cortical layers measured. Maximal amplification occurred when onset of vM1 optogenetic activation preceded vibrissa stimulation by 20 ms. In addition to amplification, vM1 activation also sharpened angular tuning of vS1 neurons in all cortical layers measured. Our findings indicated that in addition to output motor signals, vM1 also sends preparatory signals to vS1 that serve to amplify and sharpen the response of neurons in the barrel cortex to incoming sensory input signals. DOI: http://dx.doi.org/10.7554/eLife.21843.001 PMID:28059699

  20. Formation and Degradation of Furfuryl Alcohol, 5-Methylfurfuryl Alcohol, Vanillyl Alcohol, and Their Ethyl Ethers in Barrel-Aged Wines.

    PubMed

    Spillman; Pollnitz; Liacopoulos; Pardon; Sefton

    1998-02-16

    Furfural, 5-methylfurfural, and vanillin co-occurred in 64 barrel-aged red, white, and model wines with the reduction products, furfuryl alcohol, 5-methylfurfuryl alcohol, and vanillyl alcohol, and with the corresponding ethyl ethers of these alcohols. Hydrolytic studies in a model wine have shown that 5-methylfurfuryl ethyl ether is formed rapidly from 5-methylfurfuryl alcohol, but both decomposed quickly under the conditions. Vanillyl ethyl ether was also formed relatively rapidly, and both this ether and vanillyl alcohol were stable in the model wine. The formation of furfuryl ethyl ether from furfuryl alcohol and the subsequent decomposition of these two compounds were comparatively slow. The relative concentration of these aromatic alcohols and ethers in the barrel-aged wines was consistent with the observed stability of the furan derivatives, but low concentrations of vanillyl alcohol and vanillyl ethyl ether observed in all samples showed that factors other than solvolytic degradation were responsible for reducing the concentration of these compounds in wine. Furfuryl ethyl ether, which had an aroma threshold of 430 µg/L in a white wine, was found at approximate concentrations of up to 230 µg/L in the wines.

  1. Novel β-Barrel Fold in the Nuclear Magnetic Resonance Structure of the Replicase Nonstructural Protein 1 from the Severe Acute Respiratory Syndrome Coronavirus▿

    PubMed Central

    Almeida, Marcius S.; Johnson, Margaret A.; Herrmann, Torsten; Geralt, Michael; Wüthrich, Kurt

    2007-01-01

    The nonstructural protein 1 (nsp1) of the severe acute respiratory syndrome coronavirus has 179 residues and is the N-terminal cleavage product of the viral replicase polyprotein that mediates RNA replication and processing. The specific function of nsp1 is not known. Here we report the nuclear magnetic resonance structure of the nsp1 segment from residue 13 to 128, which represents a novel α/β-fold formed by a mixed parallel/antiparallel six-stranded β-barrel, an α-helix covering one opening of the barrel, and a 310-helix alongside the barrel. We further characterized the full-length 179-residue protein and show that the polypeptide segments of residues 1 to 12 and 129 to 179 are flexibly disordered. The structure is analyzed in a search for possible correlations with the recently reported activity of nsp1 in the degradation of mRNA. PMID:17202208

  2. Visualization and process understanding of material behavior in the extrusion barrel during a hot-melt extrusion process using Raman spectroscopy.

    PubMed

    Saerens, Lien; Vervaet, Chris; Remon, Jean-Paul; De Beer, Thomas

    2013-06-04

    The aim of this research was to improve understanding of material behavior in pharmaceutical hot-melt extrusion by implementing a Raman probe in each section of the barrel. Fourier-transform infrared spectroscopy measurements were performed to confirm the Raman observations. Metoprolol tartrate (MPT) concentration (10 and 40% in Eudragit RSPO), extrusion temperature (100, 120, and 140 °C), and screw speed (80 and 160 rpm) were varied to examine their influence on polymer-drug solid state throughout the barrel. When extruding a formulation with a 40% MPT concentration, the broadening of MPT peaks indicates melting of MPT between sections 2 and 3, caused by the first kneading zone. Decreasing the concentration to 10% shows an additional spectral difference (i.e., peak shifts indicating interactions between MPT and the carrier) between sections 5 and 6, due to formation of a solid solution. At a 10% MPT load, increasing the extrusion temperature does not influence the solid state or the barrel section where the final solid state is obtained. At a drug load of 40%, the solid state of the end product is reached further down the barrel when the temperature decreases. Doubling the screw speed when processing a 10% MPT formulation does not affect the solid state of the product or the location where it is obtained. In contrast, at a 40% drug load, the section where the final product is produced, is situated earlier in the barrel, when applying a higher speed. The Raman spectra provide real-time information about polymer-drug behavior throughout the barrel, facilitating process understanding and optimization.

  3. Acoustic and visual remote sensing of barrels of radioactive waste: Application of civilian and military technology to environmental management of the oceans

    SciTech Connect

    Karl, H.A.; Chin, J.L.; Maher, N.M.; Chavez, P.S. Jr.; Ueber, E.; Van Peeters, W.; Curl, H.

    1995-04-01

    As part of an ongoing strategic research project to find barrels of radioactive waste off San Francisco, the U.S. Navy (USN), the U.S. Geological Survey (USGS), and the Gulf of the Farallones National Marine Sanctuary (GFNMS) pooled their expertise, resources, and technology to form a partnership to verify new computer enhancement techniques developed for detecting targets the size of 55 gallon barrels on sidescan sonar images. Between 1946 and 1970, approximately 47,800 large barrels and other containers of radioactive waste were dumped in the ocean west of San Francisco; the containers litter an area of the sea floor of at least 1400 km {sup 2} knows as the Farallon Island Radioactive Waste Dump. The exact location of the containers and the potential hazard the containers pose to the environment is unknown. The USGS developed computer techniques and contracted with private industry to enhance sidescan data, collected in cooperation with the GFNMS, to detect objects as small as 55 gallon steel barrels while conducting regional scale sidescan sonar surveys. Using a subset of the regional sonar survey, images were plotted over a 125 km {sub 2} area. The acoustic interpretations were verified visually using the USN DSV Sea Cliff and the unmanned Advanced Tethered Vehicle (ATV). Barrels and other physical features were found where image enhancement had indicated they would be found. The interagency cooperation among the USN, USGS, and GFNMS has led to develop a cost effective and time efficient method to locate the barrels of radioactive waste. This method has universal application for locating containers of hazardous waste over a regional scale in other ocean areas such as Boston Harbor and the Kara Sea in the Arctic. This successful application of military and civilian expertise and technology has provided scientific information to help formulate policy decisions that affect the environmental management and quality of the ocean.

  4. Flow tests of the Gladys McCall well

    SciTech Connect

    Randolph, P.L.; Hayden, C.G.; Rogers, L.A. )

    1992-04-01

    This report pulls together the data from all of the geopressured-geothermal field research conducted at the Gladys McCall well. The well produced geopressured brine containing dissolved natural gas from the Lower Miocene sands at a depth of 15,150 to 16,650 feet. More than 25 million barrels of brine and 727 million standard cubic feet of natural gas were produced in a series of flow tests between December 1982 and October 1987 at various brine flow rates up to 28,000 barrels per day. Initial short-term flow tests for the Number 9 Sand found the permeability to be 67 to 85 md (millidarcies) for a brine volume of 85 to 170 million barrels. Initial short-term flow tests for the Number 8 Sand found a permeability of 113 to 132 md for a reservoir volume of 430 to 550 million barrels of brine. The long-term flow and buildup test of the Number 8 Sand found that the high-permeability reservoir connected to the wellbore (measured by the short-term flow test) was connected to a much larger, low-permeability reservoir. Numerical simulation of the flow and buildup tests required this large connected reservoir to have a volume of about 8 billion barrels (two cubic miles of reservoir rock) with effective permeabilities in the range of 0.2 to 20 md. Calcium carbonate scale formation in the well tubing and separator equipment was a problem. During the first 2 years of production, scale formation was prevented in the surface equipment by injection of an inhibitor upstream of the choke. Starting in 1985, scale formation in the production tubing was successfully prevented by injecting inhibitor pills'' directly into the reservoir. Corrosion and/or erosion of surface piping and equipment, as well as disposal well tubing, was also significant.

  5. Environmental assessment: US Department of Energy's financial incentives for production of 60,000 barrels per dya of ethanol

    SciTech Connect

    Not Available

    1981-01-01

    This document is an environmental assessment (EA) of the Department of Energy's Financial Incentives Program for Production of 60,000 barrels per day (B/D) of ethanol for use as a transportation fuel when blended with gasoline. Its purpose is to evaluate all phases of ethanol production and compare program alternatives to ensure that environmental effects are considered at the earliest meaningful point in the decision-making process, to determine the need for a programmatic environmental impact statement (EIS), and to provide an information base for the preparation of site-specific EA's and EIS's if these are necessary. Based on the findings of this environmental assessment, it is expected that the production and use of 60,000 B/D of ethanol should produce no major environmental effects. Environmental residuals, health and safety concerns, and institutional issues associated with the conversion, distribution, and end use of ethanol are discussed.

  6. Algorithm and implementation of muon trigger and data transmission system for barrel-endcap overlap region of the CMS detector

    NASA Astrophysics Data System (ADS)

    Zabolotny, W. M.; Byszuk, A.

    2016-03-01

    The CMS experiment Level-1 trigger system is undergoing an upgrade. In the barrel-endcap transition region, it is necessary to merge data from 3 types of muon detectors—RPC, DT and CSC. The Overlap Muon Track Finder (OMTF) uses the novel approach to concentrate and process those data in a uniform manner to identify muons and their transversal momentum. The paper presents the algorithm and FPGA firmware implementation of the OMTF and its data transmission system in CMS. It is foreseen that the OMTF will be subject to significant changes resulting from optimization which will be done with the aid of physics simulations. Therefore, a special, high-level, parameterized HDL implementation is necessary.

  7. Bad apples, bad cases, and bad barrels: meta-analytic evidence about sources of unethical decisions at work.

    PubMed

    Kish-Gephart, Jennifer J; Harrison, David A; Treviño, Linda Klebe

    2010-01-01

    As corporate scandals proliferate, practitioners and researchers alike need a cumulative, quantitative understanding of the antecedents associated with unethical decisions in organizations. In this meta-analysis, the authors draw from over 30 years of research and multiple literatures to examine individual ("bad apple"), moral issue ("bad case"), and organizational environment ("bad barrel") antecedents of unethical choice. Findings provide empirical support for several foundational theories and paint a clearer picture of relationships characterized by mixed results. Structural equation modeling revealed the complexity (multidetermined nature) of unethical choice, as well as a need for research that simultaneously examines different sets of antecedents. Moderator analyses unexpectedly uncovered better prediction of unethical behavior than of intention for several variables. This suggests a need to more strongly consider a new "ethical impulse" perspective in addition to the traditional "ethical calculus" perspective. Results serve as a data-based foundation and guide for future theoretical and empirical development in the domain of behavioral ethics.

  8. The Outer Membrane Protein OmpW Forms an Eight-Stranded beta-Barrel with a Hydrophobic Channel

    SciTech Connect

    Hong,H.; Patel, D.; Tamm, L.; van den Berg, B.

    2006-01-01

    Escherichia coli OmpW belongs to a family of small outer membrane (OM) proteins that are widespread in Gram-negative bacteria. Their functions are unknown, but recent data suggest that they may be involved in the protection of bacteria against various forms of environmental stress. In order to gain insight into the function of these proteins we have determined the crystal structure of Escherichia coli OmpW to 2.7 Angstroms resolution. The structure shows that OmpW forms an eight-stranded beta-barrel with a long and narrow hydrophobic channel that contains a bound LDAO detergent molecule. Single channel conductance experiments show that OmpW functions as an ion channel in planar lipid bilayers. The channel activity can be blocked by the addition of LDAO. Taken together, the data suggest that members of the OmpW family could be involved in the transport of small hydrophobic molecules across the bacterial OM.

  9. Transcriptome response to infraorbital nerve transection in the gonadally intact male rat barrel cortex: RNA-seq.

    PubMed

    Orczyk, John J; Sethia, Rishabh; Doster, Dominique; Garraghty, Preston E

    2016-01-01

    The effects of infraorbital nerve (ION) transection on gene expression in the adult male rat barrel cortex were investigated using RNA sequencing. After a 24-hour survival duration, 98 genes were differentially regulated by ION transection. Differentially expressed genes suggest changes in neuronal activity, excitability, and morphology. The production of mRNA for neurotrophins, including brain-derived neurotrophin factor (BNDF), was decreased following ION transection. Several potassium channels showed decreased mRNA production, whereas a sodium channel (Na(V)β4) associated with burst firing showed increased mRNA production. The results may have important implications for phantom-limb pain and complex regional pain syndrome. Future experiments should determine the extent to which changes in RNA result in changes in protein expression, in addition to utilizing laser capture microdissection techniques to differentiate between neuronal and glial cells.

  10. Silicification of wood adopted for barrel production using pure silicon alkoxides in gas phase to avoid microbial colonisation.

    PubMed

    Guzzon, Raffaele; Widmann, Giacomo; Bertoldi, Daniela; Nardin, Tiziana; Callone, Emanuela; Nicolini, Giorgio; Larcher, Roberto

    2015-02-01

    The paper presents a new approach, covering wood with silica-based material in order to protect it from spoilage due to microbial colonisation and avoiding the loss of the natural features of the wood. Wood specimens derived from wine barrels were treated with methyltriethoxysilane in gas phase, leading to the deposition of a silica nanofilm on the surface. (29)Si and (13)C solid state Nuclear Magnetic Resonance and Scanning Electron Microscope-Energy Dispersive X-ray analysis observations showed the formation of a silica polymeric film on the wood samples, directly bonding with the wood constituents. Inductively Coupled Plasma-Mass Spectroscopy quantification of Si showed a direct correlation between the treatment time and silica deposition on the surface of the wood. The silica-coated wood counteracted colonisation by the main wine spoilage microorganisms, without altering the migration from wood to wine of 21 simple phenols measured using a HPLC-Electrochemical Coulometric Detection.

  11. Enhancement of postsynaptic GABAA and extrasynaptic NMDA receptor-mediated responses in the barrel cortex of Mecp2-null mice

    PubMed Central

    Lo, Fu-Sun; Blue, Mary E.

    2015-01-01

    Rett syndrome (RTT) is a neurodevelopmental disorder that results from mutations in the X-linked gene for methyl-CpG-binding protein 2 (MECP2). The underlying cellular mechanism for the sensory deficits in patients with RTT is largely unknown. This study used the Bird mouse model of RTT to investigate sensory thalamocortical synaptic transmission in the barrel cortex of Mecp2-null mice. Electrophysiological results showed an excitation/inhibition imbalance, biased toward inhibition, due to an increase in efficacy of postsynaptic GABAA receptors rather than alterations in inhibitory network and presynaptic release properties. Enhanced inhibition impaired the transmission of tonic sensory signals from the thalamus to the somatosensory cortex. Previous morphological studies showed an upregulation of NMDA receptors in the neocortex of both RTT patients and Mecp2-null mice at early ages [Blue ME, Naidu S, Johnston MV. Ann Neurol 45: 541–545, 1999; Blue ME, Kaufmann WE, Bressler J, Eyring C, O'Driscoll C, Naidu S, Johnston MV. Anat Rec (Hoboken) 294: 1624–1634, 2011]. Although AMPA and NMDA receptor-mediated excitatory synaptic transmission was not altered in the barrel cortex of Mecp2-null mice, extrasynaptic NMDA receptor-mediated responses increased markedly. These responses were blocked by memantine, suggesting that extrasynaptic NMDA receptors play an important role in the pathogenesis of RTT. The results suggest that enhancement of postsynaptic GABAA and extrasynaptic NMDA receptor-mediated responses may underlie impaired somatosensation and that pharmacological blockade of extrasynaptic NMDA receptors may have therapeutic value for RTT. PMID:26683074

  12. Loss of sensory input increases the intrinsic excitability of layer 5 pyramidal neurons in rat barrel cortex.

    PubMed

    Breton, Jean-Didier; Stuart, Greg J

    2009-11-01

    Development of the cortical map is experience dependent, with different critical periods in different cortical layers. Previous work in rodent barrel cortex indicates that sensory deprivation leads to changes in synaptic transmission and plasticity in layer 2/3 and 4. Here, we studied the impact of sensory deprivation on the intrinsic properties of layer 5 pyramidal neurons located in rat barrel cortex using simultaneous somatic and dendritic recording. Sensory deprivation was achieved by clipping all the whiskers on one side of the snout. Loss of sensory input did not change somatic active and resting membrane properties, and did not influence dendritic action potential (AP) backpropagation. In contrast, sensory deprivation led to an increase in the percentage of layer 5 pyramidal neurons showing burst firing. This was associated with a reduction in the threshold for generation of dendritic calcium spikes during high-frequency AP trains. Cell-attached recordings were used to assess changes in the properties and expression of dendritic HCN channels. These experiments indicated that sensory deprivation caused a decrease in HCN channel density in distal regions of the apical dendrite. To assess the contribution of HCN down-regulation on the observed increase in dendritic excitability following sensory deprivation, we investigated the impact of blocking HCN channels. Block of HCN channels removed differences in dendritic calcium electrogenesis between control and deprived neurons. In conclusion, these observations indicate that sensory loss leads to increased dendritic excitability of cortical layer 5 pyramidal neurons. Furthermore, they suggest that increased dendritic calcium electrogenesis following sensory deprivation is mediated in part via down-regulation of dendritic HCN channels.

  13. Floral visitation by the Argentine ant reduces pollinator visitation and seed set in the coast barrel cactus, Ferocactus viridescens.

    PubMed

    LeVan, Katherine E; Hung, Keng-Lou James; McCann, Kyle R; Ludka, John T; Holway, David A

    2014-01-01

    Mounting evidence indicates that trade-offs between plant defense and reproduction arise not only from resource allocation but also from interactions among mutualists. Indirect costs of plant defense by ants, for example, can outweigh benefits if ants deter pollinators. Plants can dissuade ants from occupying flowers, but such arrangements may break down when novel ant partners infiltrate mutualisms. Here, we examine how floral visitation by ants affects pollination services when the invasive Argentine ant (Linepithema humile) replaces a native ant species in a food-for-protection mutualism with the coast barrel cactus (Ferocactus viridescens), which, like certain other barrel cacti, produces extrafloral nectar. We compared the effects of floral visitation by the Argentine ant with those of the most prevalent native ant species (Crematogaster californica). Compared to C. californica, the Argentine ant was present in higher numbers in flowers. Cactus bees (Diadasia spp.), the key pollinators in this system, spent less time in flowers when cacti were occupied by the Argentine ant compared to when cacti were occupied by C. californica. Presumably as a consequence of decreased duration of floral visits by Diadasia, cacti occupied by L. humile set fewer seeds per fruit and produced fewer seeds overall compared to cacti occupied by C. californica. These data illustrate the importance of mutualist identity in cases where plants balance multiple mutualisms. Moreover, as habitats become increasingly infiltrated by introduced species, the loss of native mutualists and their replacement by non-native species may alter the shape of trade-offs between plant defense and reproduction.

  14. Enhancement of postsynaptic GABAA and extrasynaptic NMDA receptor-mediated responses in the barrel cortex of Mecp2-null mice.

    PubMed

    Lo, Fu-Sun; Blue, Mary E; Erzurumlu, Reha S

    2016-03-01

    Rett syndrome (RTT) is a neurodevelopmental disorder that results from mutations in the X-linked gene for methyl-CpG-binding protein 2 (MECP2). The underlying cellular mechanism for the sensory deficits in patients with RTT is largely unknown. This study used the Bird mouse model of RTT to investigate sensory thalamocortical synaptic transmission in the barrel cortex of Mecp2-null mice. Electrophysiological results showed an excitation/inhibition imbalance, biased toward inhibition, due to an increase in efficacy of postsynaptic GABAA receptors rather than alterations in inhibitory network and presynaptic release properties. Enhanced inhibition impaired the transmission of tonic sensory signals from the thalamus to the somatosensory cortex. Previous morphological studies showed an upregulation of NMDA receptors in the neocortex of both RTT patients and Mecp2-null mice at early ages [Blue ME, Naidu S, Johnston MV. Ann Neurol 45: 541-545, 1999; Blue ME, Kaufmann WE, Bressler J, Eyring C, O'Driscoll C, Naidu S, Johnston MV. Anat Rec (Hoboken) 294: 1624-1634, 2011]. Although AMPA and NMDA receptor-mediated excitatory synaptic transmission was not altered in the barrel cortex of Mecp2-null mice, extrasynaptic NMDA receptor-mediated responses increased markedly. These responses were blocked by memantine, suggesting that extrasynaptic NMDA receptors play an important role in the pathogenesis of RTT. The results suggest that enhancement of postsynaptic GABAA and extrasynaptic NMDA receptor-mediated responses may underlie impaired somatosensation and that pharmacological blockade of extrasynaptic NMDA receptors may have therapeutic value for RTT.

  15. A triple-barreled microelectrode for simultaneous measurements of intracellular Na+ and K+ activities and membrane potential in biological cells.

    PubMed

    Fujimoto, M; Honda, M

    1980-01-01

    A triple-barreled Na+, K+-selective microelectrode was constructed with liquid ion exchangers for Na+ (monensin) and K+ (Corning #477317) to measure the intracellular Na+ and K+ activities ((Na)i and (K)i) of a single cell and its membrane potential (EM), simultaneously. The tip of the triple-barreled assembly was made less than 0.6 micron in outside diameter. Prior to in vivo measurements, some physiochemical properties of microelectrodes were examined in vitro for the slope constant, selectivity coefficient, electrical resistance, and pH effect, as well as measurements of the activity coefficient on ions in blood serum and Ringer solution. Carrying out direct micropunctures on single cells of the sartorius muscle and renal proximal tubule of bullfrogs in vivo, we obtained the following results: (1) In sartorius muscle, the average (Na)i was 14.8 mEq/liter, the (K)i 64.5 mEq/liter, and the EM -86.2 mV. (2) In proximal tubule cells, the average (Na)i, (K)i and EM were 16.8, 63.0 mEq/liter and -65.9 mV, respectively. (3) There were significant correlations in the proximal tubule between (K)i and EM, and inversely between (Na)i and EM, and between (Na)i and (K)i. These facts may somehow be related to both the activity of Na+-K+ exchange pump and the osmotic equilibrium of water across the membrane. Further, several problems inherent in the multibarreled microelectrode were discussed from the practical point of view.

  16. Trypanosomal TAC40 constitutes a novel subclass of mitochondrial β-barrel proteins specialized in mitochondrial genome inheritance.

    PubMed

    Schnarwiler, Felix; Niemann, Moritz; Doiron, Nicholas; Harsman, Anke; Käser, Sandro; Mani, Jan; Chanfon, Astrid; Dewar, Caroline E; Oeljeklaus, Silke; Jackson, Christopher B; Pusnik, Mascha; Schmidt, Oliver; Meisinger, Chris; Hiller, Sebastian; Warscheid, Bettina; Schnaufer, Achim C; Ochsenreiter, Torsten; Schneider, André

    2014-05-27

    Mitochondria cannot form de novo but require mechanisms allowing their inheritance to daughter cells. In contrast to most other eukaryotes Trypanosoma brucei has a single mitochondrion whose single-unit genome is physically connected to the flagellum. Here we identify a β-barrel mitochondrial outer membrane protein, termed tripartite attachment complex 40 (TAC40), that localizes to this connection. TAC40 is essential for mitochondrial DNA inheritance and belongs to the mitochondrial porin protein family. However, it is not specifically related to any of the three subclasses of mitochondrial porins represented by the metabolite transporter voltage-dependent anion channel (VDAC), the protein translocator of the outer membrane 40 (TOM40), or the fungi-specific MDM10, a component of the endoplasmic reticulum-mitochondria encounter structure (ERMES). MDM10 and TAC40 mediate cellular architecture and participate in transmembrane complexes that are essential for mitochondrial DNA inheritance. In yeast MDM10, in the context of the ERMES, is postulated to connect the mitochondrial genomes to actin filaments, whereas in trypanosomes TAC40 mediates the linkage of the mitochondrial DNA to the basal body of the flagellum. However, TAC40 does not colocalize with trypanosomal orthologs of ERMES components and, unlike MDM10, it regulates neither mitochondrial morphology nor the assembly of the protein translocase. TAC40 therefore defines a novel subclass of mitochondrial porins that is distinct from VDAC, TOM40, and MDM10. However, whereas the architecture of the TAC40-containing complex in trypanosomes and the MDM10-containing ERMES in yeast is very different, both are organized around a β-barrel protein of the mitochondrial porin family that mediates a DNA-cytoskeleton linkage that is essential for mitochondrial DNA inheritance.

  17. Trypanosomal TAC40 constitutes a novel subclass of mitochondrial β-barrel proteins specialized in mitochondrial genome inheritance

    PubMed Central

    Schnarwiler, Felix; Niemann, Moritz; Doiron, Nicholas; Harsman, Anke; Käser, Sandro; Mani, Jan; Chanfon, Astrid; Dewar, Caroline E.; Oeljeklaus, Silke; Jackson, Christopher B.; Pusnik, Mascha; Schmidt, Oliver; Meisinger, Chris; Hiller, Sebastian; Warscheid, Bettina; Schnaufer, Achim C.; Ochsenreiter, Torsten; Schneider, André

    2014-01-01

    Mitochondria cannot form de novo but require mechanisms allowing their inheritance to daughter cells. In contrast to most other eukaryotes Trypanosoma brucei has a single mitochondrion whose single-unit genome is physically connected to the flagellum. Here we identify a β-barrel mitochondrial outer membrane protein, termed tripartite attachment complex 40 (TAC40), that localizes to this connection. TAC40 is essential for mitochondrial DNA inheritance and belongs to the mitochondrial porin protein family. However, it is not specifically related to any of the three subclasses of mitochondrial porins represented by the metabolite transporter voltage-dependent anion channel (VDAC), the protein translocator of the outer membrane 40 (TOM40), or the fungi-specific MDM10, a component of the endoplasmic reticulum–mitochondria encounter structure (ERMES). MDM10 and TAC40 mediate cellular architecture and participate in transmembrane complexes that are essential for mitochondrial DNA inheritance. In yeast MDM10, in the context of the ERMES, is postulated to connect the mitochondrial genomes to actin filaments, whereas in trypanosomes TAC40 mediates the linkage of the mitochondrial DNA to the basal body of the flagellum. However, TAC40 does not colocalize with trypanosomal orthologs of ERMES components and, unlike MDM10, it regulates neither mitochondrial morphology nor the assembly of the protein translocase. TAC40 therefore defines a novel subclass of mitochondrial porins that is distinct from VDAC, TOM40, and MDM10. However, whereas the architecture of the TAC40-containing complex in trypanosomes and the MDM10-containing ERMES in yeast is very different, both are organized around a β-barrel protein of the mitochondrial porin family that mediates a DNA–cytoskeleton linkage that is essential for mitochondrial DNA inheritance. PMID:24821793

  18. Self-assembly of the beta2-microglobulin NHVTLSQ peptide using a coarse-grained protein model reveals a beta-barrel species.

    PubMed

    Song, Wei; Wei, Guanghong; Mousseau, Normand; Derreumaux, Philippe

    2008-04-10

    Although a wide variety of proteins can assemble into amyloid fibrils, the structure of the early oligomeric species on the aggregation pathways remains unknown at an atomic level of detail. In this paper we report, using molecular dynamics simulations with the OPEP coarse-grained force field, the free energy landscape of a tetramer and a heptamer of the beta2-microglobulin NHVTLSQ peptide. On the basis of a total of more than 17 ns trajectories started from various states, we find that both species are in equilibrium between amorphous and well-ordered aggregates with cross-beta-structure, a perpendicular bilayer beta-sheet, and, for the heptamer, six- or seven-stranded closed and open beta-barrels. Moreover, analysis of the heptamer trajectories shows that the perpendicular bilayer beta-sheet is one possible precursor of the beta-barrel, but that this barrel can also be formed from a twisted monolayer beta-sheet with successive addition of chains. Comparison with previous aggregation simulations and the fact that nature constructs transmembrane beta-sheet proteins with pores open the possibility that beta-barrels with small inner diameters may represent a common intermediate during the early steps of aggregation.

  19. Volatile compounds and sensorial characterization of wines from four Spanish denominations of origin, aged in Spanish Rebollo (Quercus pyrenaica Willd.) oak wood barrels.

    PubMed

    Fernández de Simón, Brígida; Cadahía, Estrella; Sanz, Miriam; Poveda, Pilar; Perez-Magariño, Silvia; Ortega-Heras, Miriam; González-Huerta, Carlos

    2008-10-08

    The evolution of almost 40 oak-related volatile compounds and the sensorial characteristics of red wines from four Spanish denominations of origin (DOs) (Bierzo, Toro, Ribera de Duero, and Rioja) during aging in barrels made of Rebollo oak wood, Quercus pyrenaica, were studied and compared to the same wines aged in American and French oak barrels. Each oak wood added unique and special characteristics to the wine, and in addition, each wine showed a different ability to extract the compounds, which result in these characteristics from the oak wood. In general, wines aged in Q. pyrenaica wood were characterized by high levels of eugenol, guaiacol, and other volatile phenols. In regards to compounds like cis-whiskylactone or maltol, the behavior of this wood is very similar to that of American oaks. When considering phenolic aldehydes and ketones, the levels of these compounds are intermediate between those of French and American woods and depend greatly on the type of wine. The type of oak, on the other hand, does not affect the chromatic characteristics of the wines. In sensory analysis, the biggest differences are found in the olfactory phase. Among the four DOs studied, wine aged in Q. pyrenaica presented the highest notes of wood, with more aromas of roasting, toasting, milky coffee, spices, or wine-wood interactions. The wines aged in barrels made of Q. pyrenaica wood were highly regarded, and preference was shown for them over those same wines when they had been aged in barrels of American or French oak.

  20. Functional recovery of neuronal activity in rat whisker-barrel cortex sensory pathway from freezing injury after transplantation of adult bone marrow stromal cells.

    PubMed

    Mori, Kentaro; Iwata, Junko; Miyazaki, Masahiro; Nakao, Yasuaki; Maeda, Minoru

    2005-07-01

    The effect of transplantation of adult bone marrow stromal cells (MSCs) into the freeze-lesioned left barrel field cortex in the rat was investigated by measurement of local cerebral glucose utilization (lCMR(glc)) in the anatomic structures of the whisker-to-barrel cortex sensory pathway. Bone marrow stromal cells or phosphate-buffered saline (PBS) were injected intracerebrally into the boundary zone 1 h after induction of the freezing cortical lesion. Three weeks after surgery, the 2-[(14)C]deoxyglucose method was used to measure lCMR(glc) during right whisker stimulation. The volume of the primary necrotic freezing lesion was significantly reduced (P<0.05), and secondary retrograde degeneration in the left ventral posteromedial (VPM) thalamic nucleus was diminished in the MSC-treated group. Local cerebral glucose utilization measurements showed that the freezing cortical lesion did not alter the metabolic responses to stimulation in the brain stem trigeminal nuclei, but eliminated the responses in the left VPM nucleus and periphery of the barrel cortex in the PBS-treated group. The left/right (stimulated/unstimulated) lCMR(glc) ratios were significantly improved in both the VPM nucleus and periphery of the barrel cortex in the MSC-treated group compared with the PBS-treated group (P<0.05). These results indicate that MSC transplantation in adults may stimulate metabolic and functional recovery in injured neuronal pathways.

  1. Dissociation of synaptic zinc level and zinc transporter 3 expression during postnatal development and after sensory deprivation in the barrel cortex of mice.

    PubMed

    Liguz-Lecznar, Monika; Nowicka, Dorota; Czupryn, Artur; Skangiel-Kramska, Jolanta

    2005-07-30

    In the neocortex, synaptic zinc level is regulated by sensory experience. Previously, we found that trimming of mystacial vibrissae resulted in an increase of synaptic zinc level in corresponding deprived barrels in the cortex of mice. The present study focused on the relationship between synaptic zinc and zinc transporter 3 (ZnT3) protein expression in the barrel cortex of mice during postnatal development and after sensory deprivation of selected vibrissae. Using immunocytochemistry and western blot analysis, we found that ZnT3 expression is delayed as compared with the onset of synaptic zinc and presynaptic markers, such as synapsin I and synaptophysin. Further, neither long-term deprivation in young mice nor short deprivation in adult mice, that resulted in an increase of synaptic zinc level, produced alterations in ZnT3, synapsin I or synaptophysin expression in deprived barrels. These results suggest that in the barrel cortex ZnT3, synapsin I or synaptophysin are not determinant for the activity-dependent regulation of the synaptic zinc level.

  2. Hemolytic lectin CEL-III heptamerizes via a large structural transition from α-helices to a β-barrel during the transmembrane pore formation process.

    PubMed

    Unno, Hideaki; Goda, Shuichiro; Hatakeyama, Tomomitsu

    2014-05-02

    CEL-III is a hemolytic lectin isolated from the sea cucumber Cucumaria echinata. This lectin is composed of two carbohydrate-binding domains (domains 1 and 2) and one oligomerization domain (domain 3). After binding to the cell surface carbohydrate chains through domains 1 and 2, domain 3 self-associates to form transmembrane pores, leading to cell lysis or death, which resembles other pore-forming toxins of diverse organisms. To elucidate the pore formation mechanism of CEL-III, the crystal structure of the CEL-III oligomer was determined. The CEL-III oligomer has a heptameric structure with a long β-barrel as a transmembrane pore. This β-barrel is composed of 14 β-strands resulting from a large structural transition of α-helices accommodated in the interface between domains 1 and 2 and domain 3 in the monomeric structure, suggesting that the dissociation of these α-helices triggered their structural transition into a β-barrel. After heptamerization, domains 1 and 2 form a flat ring, in which all carbohydrate-binding sites remain bound to cell surface carbohydrate chains, stabilizing the transmembrane β-barrel in a position perpendicular to the plane of the lipid bilayer.

  3. Neurons in the barrel cortex turn into processing whisker and odor signals: a cellular mechanism for the storage and retrieval of associative signals

    PubMed Central

    Wang, Dangui; Zhao, Jun; Gao, Zilong; Chen, Na; Wen, Bo; Lu, Wei; Lei, Zhuofan; Chen, Changfeng; Liu, Yahui; Feng, Jing; Wang, Jin-Hui

    2015-01-01

    Associative learning and memory are essential to logical thinking and cognition. How the neurons are recruited as associative memory cells to encode multiple input signals for their associated storage and distinguishable retrieval remains unclear. We studied this issue in the barrel cortex by in vivo two-photon calcium imaging, electrophysiology, and neural tracing in our mouse model that the simultaneous whisker and olfaction stimulations led to odorant-induced whisker motion. After this cross-modal reflex arose, the barrel and piriform cortices connected. More than 40% of barrel cortical neurons became to encode odor signal alongside whisker signal. Some of these neurons expressed distinct activity patterns in response to acquired odor signal and innate whisker signal, and others encoded similar pattern in response to these signals. In the meantime, certain barrel cortical astrocytes encoded odorant and whisker signals. After associative learning, the neurons and astrocytes in the sensory cortices are able to store the newly learnt signal (cross-modal memory) besides the innate signal (native-modal memory). Such associative memory cells distinguish the differences of these signals by programming different codes and signify the historical associations of these signals by similar codes in information retrievals. PMID:26347609

  4. A methodology for fast assessments to the electrical activity of barrel fields in vivo: from population inputs to single unit outputs

    PubMed Central

    Riera, Jorge J.; Goto, Takakuni; Kawashima, Ryuta

    2014-01-01

    Here we propose a methodology to analyze volumetric electrical activity of neuronal masses in the somatosensory barrel field of Wistar rats. The key elements of the proposed methodology are a three-dimensional microelectrode array, which was customized by our group to observe extracellular recordings from an extended area of the barrel field, and a novel method for the current source density analysis. By means of this methodology, we were able to localize single barrels from their event-related responses to single whisker deflection. It was also possible to assess the spatiotemporal dynamics of neuronal aggregates in several barrels at the same time with the resolution of single neurons. We used simulations to study the robustness of our methodology to unavoidable physiological noise and electrode configuration. We compared the accuracy to reconstruct neocortical current sources with that obtained with a previous method. This constitutes a type of electrophysiological microscopy with high spatial and temporal resolution, which could change the way we analyze the activity of cortical neurons in the future. PMID:24550785

  5. Alternative splice variants in TIM barrel proteins from human genome correlate with the structural and evolutionary modularity of this versatile protein fold.

    PubMed

    Ochoa-Leyva, Adrián; Montero-Morán, Gabriela; Saab-Rincón, Gloria; Brieba, Luis G; Soberón, Xavier

    2013-01-01

    After the surprisingly low number of genes identified in the human genome, alternative splicing emerged as a major mechanism to generate protein diversity in higher eukaryotes. However, it is still not known if its prevalence along the genome evolution has contributed to the overall functional protein diversity or if it simply reflects splicing noise. The (βα)8 barrel or TIM barrel is one of the most frequent, versatile, and ancient fold encountered among enzymes. Here, we analyze the structural modifications present in TIM barrel proteins from the human genome product of alternative splicing events. We found that 87% of all splicing events involved deletions; most of these events resulted in protein fragments that corresponded to the (βα)2, (βα)4, (βα)5, (βα)6, and (βα)7 subdomains of TIM barrels. Because approximately 7% of all the splicing events involved internal β-strand substitutions, we decided, based on the genomic data, to design β-strand and α-helix substitutions in a well-studied TIM barrel enzyme. The biochemical characterization of one of the chimeric variants suggests that some of the splice variants in the human genome with β-strand substitutions may be evolving novel functions via either the oligomeric state or substrate specificity. We provide results of how the splice variants represent subdomains that correlate with the independently folding and evolving structural units previously reported. This work is the first to observe a link between the structural features of the barrel and a recurrent genetic mechanism. Our results suggest that it is reasonable to expect that a sizeable fraction of splice variants found in the human genome represent structurally viable functional proteins. Our data provide additional support for the hypothesis of the origin of the TIM barrel fold through the assembly of smaller subdomains. We suggest a model of how nature explores new proteins through alternative splicing as a mechanism to diversify the

  6. Alternative Splice Variants in TIM Barrel Proteins from Human Genome Correlate with the Structural and Evolutionary Modularity of this Versatile Protein Fold

    PubMed Central

    Ochoa-Leyva, Adrián; Montero-Morán, Gabriela; Saab-Rincón, Gloria; Brieba, Luis G.; Soberón, Xavier

    2013-01-01

    After the surprisingly low number of genes identified in the human genome, alternative splicing emerged as a major mechanism to generate protein diversity in higher eukaryotes. However, it is still not known if its prevalence along the genome evolution has contributed to the overall functional protein diversity or if it simply reflects splicing noise. The (βα)8 barrel or TIM barrel is one of the most frequent, versatile, and ancient fold encountered among enzymes. Here, we analyze the structural modifications present in TIM barrel proteins from the human genome product of alternative splicing events. We found that 87% of all splicing events involved deletions; most of these events resulted in protein fragments that corresponded to the (βα)2, (βα)4, (βα)5, (βα)6, and (βα)7 subdomains of TIM barrels. Because approximately 7% of all the splicing events involved internal β-strand substitutions, we decided, based on the genomic data, to design β-strand and α-helix substitutions in a well-studied TIM barrel enzyme. The biochemical characterization of one of the chimeric variants suggests that some of the splice variants in the human genome with β-strand substitutions may be evolving novel functions via either the oligomeric state or substrate specificity. We provide results of how the splice variants represent subdomains that correlate with the independently folding and evolving structural units previously reported. This work is the first to observe a link between the structural features of the barrel and a recurrent genetic mechanism. Our results suggest that it is reasonable to expect that a sizeable fraction of splice variants found in the human genome represent structurally viable functional proteins. Our data provide additional support for the hypothesis of the origin of the TIM barrel fold through the assembly of smaller subdomains. We suggest a model of how nature explores new proteins through alternative splicing as a mechanism to diversify the

  7. Identification, amounts, and kinetics of extraction of C-glucosidic ellagitannins during wine aging in oak barrels or in stainless steel tanks with oak chips.

    PubMed

    Jourdes, Michaël; Michel, Julien; Saucier, Cédric; Quideau, Stéphane; Teissedre, Pierre-Louis

    2011-09-01

    The C-glucosidic ellagitannins are found in wine as a result of its aging in oak barrels or in stainless steel tanks with oak chips. Once dissolved in this slightly acidic solution, the C-glucosidic ellagitannins vescalagin can react with nucleophilic entities present in red wine, such as ethanol, catechin, and epicatechin, to generate condensed hybrid products such as the β-1-O-ethylvescalagin and the flavano-ellagitannins (acutissimin A/B and epiacutissimin A/B), respectively. During this study, we first monitored the extraction kinetic and the evolution of the eight major oak-derived C-glucosidic ellagitannins in red wines aged in oak barrels or in stainless steel tank with oak chips. Their extraction rates appeared to be faster during red wine aging in stainless steel tanks with oak chips. However, their overall concentrations in wines were found higher in the wine aged in barrels. The formation rates of the vescalagin-coupled derivatives were also estimated for the first time under both red wine aging conditions (i.e., oak barrels or stainless steel tanks with oak chips). As observed for the oak-native C-glucosidic ellagitannins, the concentrations of these vescalagin derivatives were higher in the red wine aged in oak barrels than in stainless steel tanks with oak chips. Despite these differences, their relative composition was similar under both red wine aging conditions. Finally, the impact of the oak chips size and toasting level on the C-glucosidic ellagitannins concentration in wine was also investigated.

  8. Fuel Retrieval Sub Project (FRS) Stuck Fuel Station Performance Test Data Report

    SciTech Connect

    THIELGES, J.R.

    2000-02-23

    This document provides the test data report for Stuck Fuel Station Performance Testing in support of the Fuel Retrieval Sub-Project. The stuck fuel station was designed to provide a means of cutting open a canister barrel to release fuel elements, etc.

  9. Experience in testing of a solution mined storage cavern. [Strategic Petroleum Reserve

    SciTech Connect

    Goin, K.L.

    1982-01-01

    Recertification tests were made of the Department of Energy/Strategic Petroleum Reserve oil storage cavern number 6 in the West Hackberry, Louisiana Salt Dome. The cavern has a volume of 8,600,000 barrels. Tests included hydrostatic tests of the brine filled cavern and nitrogen leak tests of the three wells entering the cavern. Test procedures are described and test results are discussed.

  10. Electrical Discharge Machining (EDM) Gun Barrel Bore and Rifling Feasibility Study

    DTIC Science & Technology

    1974-09-01

    Thf ^Tl B - =— whieh glows when the high sc"e ifuaed^ ndT ^" ^ f "* Hght glows when the low scale is in use Th/f green Ilght "hich... stroke limitations. 3.3 EDM ELECTRODE DEVELOPMENT A series of test cuts were made to determine the electroue material and EDM cutting parameters

  11. Gas Chemistry Effects on Gun Barrel Erosion. A Shock Tube Gun Investigation

    DTIC Science & Technology

    1982-06-01

    microprocessor, programmed to print out time versus both temperature and total heat input for both data channels. Figure S is an example of plotted data...8.1. To delineate the effects of temperature and C02 or CO concentration ,ith erosivity,data from these four test groups were plotted as functions of CO...Tech Lib ATTN: G. Wolken White Sands Missile Range, Columbus, OH 43201 NM 88002 1 Lawrence Livermore Laboratory Commander ATTN: J. Kury US Army Air

  12. Low- but Not High-Frequency LFP Correlates with Spontaneous BOLD Fluctuations in Rat Whisker Barrel Cortex

    PubMed Central

    Lu, Hanbing; Wang, Leiming; Rea, William W.; Brynildsen, Julia K.; Jaime, Saul; Zuo, Yantao; Stein, Elliot A.; Yang, Yihong

    2016-01-01

    Resting-state magnetic resonance imaging (rsMRI) is thought to reflect ongoing spontaneous brain activity. However, the precise neurophysiological basis of rsMRI signal remains elusive. Converging evidence supports the notion that local field potential (LFP) signal in the high-frequency range correlates with fMRI response evoked by a task (e.g., visual stimulation). It remains uncertain whether this relationship extends to rsMRI. In this study, we systematically modulated LFP signal in the whisker barrel cortex (WBC) by unilateral deflection of rat whiskers. Results show that functional connectivity between bilateral WBC was significantly modulated at the 2 Hz, but not at the 4 or 6 Hz, stimulus condition. Electrophysiologically, only in the low-frequency range (<5 Hz) was the LFP power synchrony in bilateral WBC significantly modulated at 2 Hz, but not at 4- or 6-Hz whisker stimulation, thus distinguishing these 2 experimental conditions, and paralleling the findings in rsMRI. LFP power synchrony in other frequency ranges was modulated in a way that was neither unique to the specific stimulus conditions nor parallel to the fMRI results. Our results support the hypothesis that emphasizes the role of low-frequency LFP signal underlying rsMRI. PMID:25331598

  13. Bidirectional Hebbian Plasticity Induced by Low-Frequency Stimulation in Basal Dendrites of Rat Barrel Cortex Layer 5 Pyramidal Neurons.

    PubMed

    Díez-García, Andrea; Barros-Zulaica, Natali; Núñez, Ángel; Buño, Washington; Fernández de Sevilla, David

    2017-01-01

    According to Hebb's original hypothesis (Hebb, 1949), synapses are reinforced when presynaptic activity triggers postsynaptic firing, resulting in long-term potentiation (LTP) of synaptic efficacy. Long-term depression (LTD) is a use-dependent decrease in synaptic strength that is thought to be due to synaptic input causing a weak postsynaptic effect. Although the mechanisms that mediate long-term synaptic plasticity have been investigated for at least three decades not all question have as yet been answered. Therefore, we aimed at determining the mechanisms that generate LTP or LTD with the simplest possible protocol. Low-frequency stimulation of basal dendrite inputs in Layer 5 pyramidal neurons of the rat barrel cortex induces LTP. This stimulation triggered an EPSP, an action potential (AP) burst, and a Ca(2+) spike. The same stimulation induced LTD following manipulations that reduced the Ca(2+) spike and Ca(2+) signal or the AP burst. Low-frequency whisker deflections induced similar bidirectional plasticity of action potential evoked responses in anesthetized rats. These results suggest that both in vitro and in vivo similar mechanisms regulate the balance between LTP and LTD. This simple induction form of bidirectional hebbian plasticity could be present in the natural conditions to regulate the detection, flow, and storage of sensorimotor information.

  14. First Approach to the Analytical Characterization of
Barrel-Aged Grape Marc Distillates Using Phenolic Compounds and Colour Parameters

    PubMed Central

    Rodríguez-Solana, Raquel; Salgado, José Manuel; Domínguez, José Manuel

    2014-01-01

    Summary Phenolic compounds (benzoic and cinnamic acid derivatives) were determined by high-performance liquid chromatography with multiple wavelength detector (HPLC- -MWD) in grape marc distillates aged in Quercus petraea, Quercus robur and Quercus alba wooden barrels. In addition to colour indices and evaluable polyphenols, all samples were described by sensorial analysis. There were significant differences in the mean concentrations of the majority of phenolic compounds among the samples. Gallic and benzoic acids were the most abundant and samples aged in Q. robur from Galicia (NW of Spain) had the highest concentration of most of the determined phenols. Grape marc distillates aged in Q. robur obtained the highest values of all sensorial attributes, whereas samples aged in Q. petraea and Q. alba obtained similar scores. Principal component analysis accounted for 88.32% of total variance, showing a good separation of aged distillates in terms of phenolic compounds and colour characteristics, according to the species and origin of the oak wood used in the ageing process. PMID:27904312

  15. Free Body Dynamics of a Spinning Cylinder With Planar Restraint (a.k.a. Barrel of Fun)

    NASA Technical Reports Server (NTRS)

    Moraru, Laurentiu; Dimofte, Florin; Hendricks, Robert C.

    2006-01-01

    The dynamic motion of a cylinder on a floor or hard surface is both entertaining and instructive. With maintenance torques, motion can be sustained and controlled as illustrated in a video clip that can be viewed in the PDF file of this document. The analysis of such a cylinder with and without end caps is burned on rotation about its center of mass and restrained by a plane normal to the axis passing through its center of mass at an angle alpha. For small values of alpha, the governing equations are simplified, and for symmetric bodies, stability requires rotation greater than [2 square root of(JWL*)]/J(sub X), where J is the transverse mass moment of inertia, W is the weight of the cylinder, L* is the cylinder length from the base to the center of mass, and JX is the mass moment of inertia about the longitudinal axis OX of the barrel. Comparisons to data are made and some applications are discussed.

  16. LFP-guided targeting of a cortical barrel column for in vivo two-photon calcium imaging

    PubMed Central

    Lee, Joon-Hyuk; Shin, Hee-Sup; Lee, Kwang-Hyung; Chung, Sooyoung

    2015-01-01

    Two-photon microscopy of bulk-loaded functional dyes is an outstanding physiological technique that enables simultaneous functional mapping of hundreds of brain cells in vivo at single-cell resolution. However, precise targeting of a specific cortical location is not easy due to its fine dimensionality. To enable precise targeting, intrinsic-signal optical imaging is often additionally performed. However, the intrinsic-signal optical imaging is not only time-consuming but also ineffective in ensuring precision. Here, we propose an alternative method for precise targeting based on local field potential (LFP) recording, a conventional electrophysiological method. The heart of this method lies in use of the same glass pipette to record LFPs and to eject calcium dye. After confirming the target area by LFP using a glass pipette, the calcium dye is ejected from the same pipette without a time delay or spatial adjustment. As a result, the calcium dye is loaded into the same ensemble of brain cells from which the LFP was obtained. As a validation of the proposed LFP-based method, we targeted and successfully loaded calcium dye into layer 2/3 of a mouse barrel column. PMID:26511063

  17. Improvement of the catalytic performance of a Bispora antennata cellulase by replacing the N-terminal semi-barrel structure.

    PubMed

    Zheng, Fei; Huang, Huoqing; Wang, Xiaoyu; Tu, Tao; Liu, Qiong; Meng, Kun; Wang, Yuan; Su, Xiaoyun; Xie, Xiangming; Luo, Huiying

    2016-10-01

    The aim of this work was to study the contribution of the N-terminal structure to cellulase catalytic performance. A wild-type cellulase (BaCel5) of glycosyl hydrolase (GH) family 5 from Bispora antennata and two hybrid enzymes (BaCel5(127) and BaCel5(167)) with replacement of the N-terminal (βα)3 (127 residues) or (βα)4 (167 residues)-barrel with the corresponding sequences of TeEgl5A from Talaromyces emersonii were produced in Pichia pastoris and biochemically characterized. BaCel5 exhibited optimal activity at pH 5.0 and 50°C but had low catalytic efficiency (25.4±0.8mLs(-1)mg(-1)). In contrast, BaCel5(127) and BaCel5(167) showed similar enzymatic properties but improved catalytic performance. When using CMC-Na, barley β-glucan, lichenan, and cellooligosaccharides as substrates, BaCel5(127) and BaCel5(167) had increased specific activities and catalytic efficiencies by ∼1.8-6.7-fold and ∼1.0-4.7-fold, respectively. The catalytic efficiency of BaCel5(167) was even higher than that of parental proteins. The underlying mechanism was analyzed by molecular docking and molecular dynamic simulation.

  18. Hydrophobization of polymer particles by tetrafluoromethane (CF4) plasma irradiation using a barrel-plasma-treatment system

    NASA Astrophysics Data System (ADS)

    Matsubara, Keisuke; Danno, Masato; Inoue, Mitsuhiro; Nishizawa, Hideki; Honda, Yuji; Abe, Takayuki

    2013-11-01

    In this study, tetrafluoromethane (CF4) plasma-treatments of polymethylmethacrylate (PMMA) powder were performed using a polygonal barrel-plasma-treatment system to improve the PMMA's hydrophobicity. Characterization of the treated samples showed that the PMMA particle surfaces were fluorinated by the CF4 treatment. The smooth surfaces of the particles changed into nano-sized worm-like structures after the plasma-treatment. The hydrophobicity of the treated PMMA samples was superior to that of the untreated samples. It was noted that the hydrophobicity of the treated samples and the surface fluorination level depended on the plasma-treatment time and radiofrequency (RF) power; high RF power increased the sample temperature, which in turn decreased the hydrophobicity of the treated samples and the surface fluorination because of the thermal decomposition of PMMA. The water-repellent effects were evaluated by using paper towels to show the application of the plasma-treated PMMA particles, with the result that the paper towel coated with the treated sample was highly water-repellent.

  19. LFP-guided targeting of a cortical barrel column for in vivo two-photon calcium imaging.

    PubMed

    Lee, Joon-Hyuk; Shin, Hee-Sup; Lee, Kwang-Hyung; Chung, Sooyoung

    2015-10-29

    Two-photon microscopy of bulk-loaded functional dyes is an outstanding physiological technique that enables simultaneous functional mapping of hundreds of brain cells in vivo at single-cell resolution. However, precise targeting of a specific cortical location is not easy due to its fine dimensionality. To enable precise targeting, intrinsic-signal optical imaging is often additionally performed. However, the intrinsic-signal optical imaging is not only time-consuming but also ineffective in ensuring precision. Here, we propose an alternative method for precise targeting based on local field potential (LFP) recording, a conventional electrophysiological method. The heart of this method lies in use of the same glass pipette to record LFPs and to eject calcium dye. After confirming the target area by LFP using a glass pipette, the calcium dye is ejected from the same pipette without a time delay or spatial adjustment. As a result, the calcium dye is loaded into the same ensemble of brain cells from which the LFP was obtained. As a validation of the proposed LFP-based method, we targeted and successfully loaded calcium dye into layer 2/3 of a mouse barrel column.

  20. Influence of wood barrels classified by NIRS on the ellagitannin content/composition and on the organoleptic properties of wine.

    PubMed

    Michel, Julien; Jourdes, Michael; Le Floch, Alexandra; Giordanengo, Thomas; Mourey, Nicolas; Teissedre, Pierre-Louis

    2013-11-20

    Ellagitannins are extracted from oak wood during wine aging in oak barrels. This research is based on the NIRS (Oakscan) oak wood classification according to their index polyphenolic (IP) (between 21.07 and 70.15). Their level in wood is very variable (between 5.95 and 32.91 mg/g dry wood) and influenced their concentration in red wine (between 2.30 and 32.56 mg/L after 24 months of aging) and thus their impact on wine organoleptic properties. The results show a good correlation between the NIRS classification and the chemical analysis (HPLC-UV-MS and acidic hydrolysis procedure) and with the wood ellagitannin level, the ellagitannin extraction kinetic, and the ellagitannins evolution in red wine (Cabernet Sauvignon). Moreover, a correlation between the NIRS classification and the increasing intensity of some wood aromas (woody, spicy, vanilla, and smoked/toasted), flavors (bitterness and astringency), and a decreasing intensity of fruitiness was also observed.

  1. Parvalbumin-Expressing GABAergic Neurons in Mouse Barrel Cortex Contribute to Gating a Goal-Directed Sensorimotor Transformation

    PubMed Central

    Sachidhanandam, Shankar; Sermet, B. Semihcan; Petersen, Carl C.H.

    2016-01-01

    Summary Sensory processing in neocortex is primarily driven by glutamatergic excitation, which is counterbalanced by GABAergic inhibition, mediated by a diversity of largely local inhibitory interneurons. Here, we trained mice to lick a reward spout in response to whisker deflection, and we recorded from genetically defined GABAergic inhibitory neurons in layer 2/3 of the primary somatosensory barrel cortex. Parvalbumin-expressing (PV), vasoactive intestinal peptide-expressing (VIP), and somatostatin-expressing (SST) neurons displayed distinct action potential firing dynamics during task performance. Whereas SST neurons fired at low rates, both PV and VIP neurons fired at high rates both spontaneously and in response to whisker stimulation. After an initial outcome-invariant early sensory response, PV neurons had lower firing rates in hit trials compared to miss trials. Optogenetic inhibition of PV neurons during this time period enhanced behavioral performance. Hence, PV neuron activity might contribute causally to gating the sensorimotor transformation of a whisker sensory stimulus into licking motor output. PMID:27149853

  2. Bidirectional Hebbian Plasticity Induced by Low-Frequency Stimulation in Basal Dendrites of Rat Barrel Cortex Layer 5 Pyramidal Neurons

    PubMed Central

    Díez-García, Andrea; Barros-Zulaica, Natali; Núñez, Ángel; Buño, Washington; Fernández de Sevilla, David

    2017-01-01

    According to Hebb's original hypothesis (Hebb, 1949), synapses are reinforced when presynaptic activity triggers postsynaptic firing, resulting in long-term potentiation (LTP) of synaptic efficacy. Long-term depression (LTD) is a use-dependent decrease in synaptic strength that is thought to be due to synaptic input causing a weak postsynaptic effect. Although the mechanisms that mediate long-term synaptic plasticity have been investigated for at least three decades not all question have as yet been answered. Therefore, we aimed at determining the mechanisms that generate LTP or LTD with the simplest possible protocol. Low-frequency stimulation of basal dendrite inputs in Layer 5 pyramidal neurons of the rat barrel cortex induces LTP. This stimulation triggered an EPSP, an action potential (AP) burst, and a Ca2+ spike. The same stimulation induced LTD following manipulations that reduced the Ca2+ spike and Ca2+ signal or the AP burst. Low-frequency whisker deflections induced similar bidirectional plasticity of action potential evoked responses in anesthetized rats. These results suggest that both in vitro and in vivo similar mechanisms regulate the balance between LTP and LTD. This simple induction form of bidirectional hebbian plasticity could be present in the natural conditions to regulate the detection, flow, and storage of sensorimotor information. PMID:28203145

  3. Sensory deprivation differentially impacts the dendritic development of pyramidal versus non-pyramidal neurons in layer 6 of mouse barrel cortex.

    PubMed

    Chen, Chia-Chien; Tam, Danny; Brumberg, Joshua C

    2012-04-01

    Early postnatal sensory experience can have profound impacts on the structure and function of cortical circuits affecting behavior. Using the mouse whisker-to-barrel system we chronically deprived animals of normal sensory experience by bilaterally trimming their whiskers every other day from birth for the first postnatal month. Brain tissue was then processed for Golgi staining and neurons in layer 6 of barrel cortex were reconstructed in three dimensions. Dendritic and somatic parameters were compared between sensory-deprived and normal sensory experience groups. Results demonstrated that layer 6 non-pyramidal neurons in the chronically deprived group showed an expansion of their dendritic arbors. The pyramidal cells responded to sensory deprivation with increased somatic size and basilar dendritic arborization but overall decreased apical dendritic parameters. In sum, sensory deprivation impacted on the neuronal architecture of pyramidal and non-pyramidal neurons in layer 6, which may provide a substrate for observed physiological and behavioral changes resulting from whisker trimming.

  4. Construction and testing of the SLD Cerenkov Ring Imaging Detector

    SciTech Connect

    Cavalli-Sforza, M.; Coyle, P.; Coyne, D.; Gagnon, P.; Williams, D.A.; Zucchelli, P. . Inst. for Particle Physics); Whitaker, J.S.; Wilson, R.J. . Dept. of Physics); Bean, A.; Caldwell, D.; Duboscq, J.; Huber, J.; Lu, A.; Mathys, L.; McHugh, S.; Morrison, R.; Witherell, M.; Yellin, S. . Dept. of Physics); Johns

    1990-01-01

    We report on the construction of the Cerenkov Ring Imaging Detector (CRID) for the SLD experiment at the SLAC Linear Collider and the testing of its components. We include results from testing the drift boxes, liquid radiator trays, and mirrors for the barrel CRID. We also discuss development of the support systems essential for the operation of the CRID: gas and liquid recirculator systems and monitoring. 15 refs., 9 figs.

  5. Acoustic mapping as an environmental management tool: I. detection of barrels of low-level radioactive waste, Gulf of the Farallones National Marine Sanctuary, California

    USGS Publications Warehouse

    Karl, Herman A.; Schwab, William C.; Wright, A. St. C.; Drake, David E.; Chin, John L.; Danforth, William W.; Ueber, Edward

    1994-01-01

    An example of the potential of this technique is summarized herein for the Gulf of the Farallones region. More than 47 800 drums (55 gallon) and other containers of low-level radioactive waste were dumped on the continental margin offshore the San Francisco Bay between 1946 and 1970. These drums now litter a large area (1200 km2) of the sea floor within the Gulf of the Farallones National Marine Sanctuary (GFNMS). The exact location of the drums and the potential hazard the drums pose to the environment are unknown. To evaluate the risk, samples of the sediment, biota and water must be collected near and distant from the concentrations of barrels. To do this the exact location of the barrels must be known prior to sampling. The USGS, through a cooperative research agreement with GFNMS, used sidescan sonar to map two areas within the sanctuary. Total sea-floor coverage was obtained and computer-processed sonographic mosaics were constructed on board ship. Many small nongeologic targets were distributed throughout the survey areas that covered about 70 km2 on the shelf and 120 km2 on the slope. Analysis of the sidescan data suggests that the targets are 55-gallon drums. This interpretation was confirmed at one site with an underwater video and 35-mm camera system. Data were collected with both a 30-kHz and a 120-kHz sidescan system within a 15-km2 area on the shelf. We found that the barrels were more easily detected with the mid-range 30-kHz system than with the higher resolution 120-kHz system. Maps of barrel distribution derived from the sonographs are being used to design sampling schemes to evaluate the risk that the radioactivity may have on the biota and environment.

  6. Pharmacological treatment of chronic systolic heart failure: are we scraping the bottom of the barrel?

    PubMed

    Abate, Elena; Sartor, Riccardo; Ceconi, Claudio; Boffa, Giovanni M

    2010-12-01

    Heart failure is a major health problem and its prevalence is growing, primarily as a consequence of the aging of the population. Recently, we have witnessed significant progress in reducing the mortality associated with chronic heart failure due to the introduction of renin-angiotensin-aldosterone system inhibitors, beta-blocking agents and the use of electrical devices. However, the prognosis of heart failure is still so disappointing that it remains the leading cause of death in developed countries. This grim record impels the search for new therapeutic strategies. The objective of this paper is to briefly review the results of some recent trials that have been put in place to test the effects of drugs that are deemed to be potentially capable of improving the prognosis of chronic systolic heart failure patients. Despite compelling theoretical premises, the results to date appear to be weak or even disappointing.

  7. Injection barrel with a tapered structure for a low speed and small size cryogenic hydrogen pellet in medium-sized plasma fusion devices

    NASA Astrophysics Data System (ADS)

    Motojima, G.; Sakamoto, R.; Okada, H.; Nagasaki, K.; Yamada, H.; Nakamura, Y.; Kado, S.; Kobayashi, S.; Konoshima, S.; Minami, T.; Ohshima, S.; Yamamoto, S.; Mizuuchi, T.; Mutoh, T.

    2016-10-01

    An injection barrel was designed and fabricated for a small size 0.8 mm cryogenic pellet with a low speed of 200-300 m/s in medium-sized plasma fusion devices. Pellet injection with pneumatic acceleration was examined using a conventional in situ technique. A tapered structure was applied in the downstream side of the injection barrel to satisfy the requirement of pellet speed reduction by expansion of the propellant gas. Shadowgraph and light gate measurements show that the intact pellets have speeds of 260 ± 30 m/s and a typical size of 1.1-1.2 mm. The pellet ablation code based on a neutral gas shielding model shows that the penetration depth of the measured pellet parameters does not cross the plasma center, even in medium-sized plasma devices such as the Heliotron J helical device. The injection barrel with a tapered structure developed in this study is feasible for low speed pellet injection.

  8. Small-Molecule Transport by CarO, an Abundant Eight-Stranded β-Barrel Outer Membrane Protein from Acinetobacter baumannii.

    PubMed

    Zahn, Michael; D'Agostino, Tommaso; Eren, Elif; Baslé, Arnaud; Ceccarelli, Matteo; van den Berg, Bert

    2015-07-17

    Outer membrane (OM) β-barrel proteins composed of 12-18 β-strands mediate cellular entry of small molecules in Gram-negative bacteria. Small OM proteins with barrels of 10 strands or less are not known to transport small molecules. CarO (carbapenem-associated outer membrane protein) from Acinetobacter baumannii is a small OM protein that has been implicated in the uptake of ornithine and carbapenem antibiotics. Here we report crystal structures of three isoforms of CarO. The structures are very similar and show a monomeric eight-stranded barrel lacking an open channel. CarO has a substantial extracellular domain resembling a glove that contains all the divergent residues between the different isoforms. Liposome swelling experiments demonstrate that full-length CarO and a "loop-less" truncation mutant mediate small-molecule uptake at low levels but that they are unlikely to mediate passage of carbapenem antibiotics. These results are confirmed by biased molecular dynamics simulations that allowed us to quantitatively model the transport of selected small molecules.

  9. Structure of Rhodococcus equi virulence-associated protein B (VapB) reveals an eight-stranded antiparallel β-barrel consisting of two Greek-key motifs

    SciTech Connect

    Geerds, Christina; Wohlmann, Jens; Haas, Albert; Niemann, Hartmut H.

    2014-06-18

    The structure of VapB, a member of the Vap protein family that is involved in virulence of the bacterial pathogen R. equi, was determined by SAD phasing and reveals an eight-stranded antiparallel β-barrel similar to avidin, suggestive of a binding function. Made up of two Greek-key motifs, the topology of VapB is unusual or even unique. Members of the virulence-associated protein (Vap) family from the pathogen Rhodococcus equi regulate virulence in an unknown manner. They do not share recognizable sequence homology with any protein of known structure. VapB and VapA are normally associated with isolates from pigs and horses, respectively. To contribute to a molecular understanding of Vap function, the crystal structure of a protease-resistant VapB fragment was determined at 1.4 Å resolution. The structure was solved by SAD phasing employing the anomalous signal of one endogenous S atom and two bound Co ions with low occupancy. VapB is an eight-stranded antiparallel β-barrel with a single helix. Structural similarity to avidins suggests a potential binding function. Unlike other eight- or ten-stranded β-barrels found in avidins, bacterial outer membrane proteins, fatty-acid-binding proteins and lysozyme inhibitors, Vaps do not have a next-neighbour arrangement but consist of two Greek-key motifs with strand order 41238567, suggesting an unusual or even unique topology.

  10. D-Ribulose 5-Phosphate 3-Epimerase: Functional and Structural Relationships to Members of the Ribulose-Phosphate Binding (beta/alpha)8-Barrel Superfamily

    SciTech Connect

    Akana,J.; Federov, A.; Federov, E.; Novak, W.; Babbitt, P.; Almo, S.; Gerlt, J.

    2006-01-01

    The 'ribulose phosphate binding' superfamily defined by the Structural Classification of Proteins (SCOP) database is considered the result of divergent evolution from a common ({beta}/{alpha}){sub 8}-barrel ancestor. The superfamily includes D-ribulose 5-phosphate 3-epimerase (RPE), orotidine 5'-monophosphate decarboxylase (OMPDC), and 3-keto-L-gulonate 6-phosphate decarboxylase (KGPDC), members of the OMPDC suprafamily, as well as enzymes involved in histidine and tryptophan biosynthesis that utilize phosphorylated metabolites as substrates. We now report studies of the functional and structural relationships of RPE to the members of the superfamily. As suggested by the results of crystallographic studies of the RPEs from rice and Plasmodium falciparum, the RPE from Streptococcus pyogenes is activated by Zn{sup 2+} which binds with a stoichiometry of one ion per polypeptide. Although wild type RPE has a high affinity for Zn{sup 2+} and inactive apoenzyme cannot be prepared, the affinity for Zn{sup 2+} is decreased by alanine substitutions for the two histidine residues that coordinate the Zn{sup 2+} ion (H34A and H67A); these mutant proteins can be prepared in an inactive, metal-free form and activated by exogenous Zn{sup 2+}. The crystal structure of the RPE was solved at 1.8 Angstroms resolution in the presence of D-xylitol 5-phosphate, an inert analogue of the D-xylulose 5-phosphate substrate. This structure suggests that the 2,3-enediolate intermediate in the 1,1-proton transfer reaction is stabilized by bidentate coordination to the Zn{sup 2+} that also is liganded to His 34, Asp 36, His 67, and Asp 176; the carboxylate groups of the Asp residues are positioned also to function as the acid/base catalysts. Although the conformation of the bound analogue resembles those of ligands bound in the active sites of OMPDC and KGPDC, the identities of the active site residues that coordinate the essential Zn{sup 2+} and participate as acid/base catalysts are not

  11. Synaptic responses to whisker deflections in rat barrel cortex as a function of cortical layer and stimulus intensity.

    PubMed

    Wilent, W Bryan; Contreras, Diego

    2004-04-21

    To study the synaptic and spike responses of barrel cortex neurons as a function of cortical layer and stimulus intensity, we recorded intracellularly in vivo from barbiturate anesthetized rats while increasing the velocity-acceleration of the whisker deflection. Granular (Gr; layer 4) cells had the EPSP with the shortest peak and onset latency, whereas supragranular (SGr; layers 2-3) cells had the EPSP with longest duration and slowest rate of rise. Infragranular (Igr; layers 5-6) cells had intermediate values, and thus each layer was unique. The spike response peak of Gr cells was followed by IGr and then by SGr cells. In all cells, depolarization reduced the duration and amplitude of the response, but only in Gr cells did it reveal an early IPSP that cut short the EPSP. This early IPSP was associated with a large decrease in input resistance and an apparent reversal potential below spike threshold; consequently, synaptic integration in Gr cells was limited to the initial 5-7 msec of the response. In contrast, in SGr and IGr cells, results suggest an overlap in time of the EPSP and IPSP, with a small drop in input resistance and an apparent reversal potential above spike threshold, facilitating input integration for up to 20 msec. Decreasing stimulus intensity (velocity-acceleration) reduced the amplitude and increased the peak latency of the response without altering its synaptic composition. We propose that layer 4 circuits are better suited to perform coincidence detection, whereas supra and infragranular circuits are better designed for input integration.

  12. TMB-Hunt: An amino acid composition based method to screen proteomes for beta-barrel transmembrane proteins

    PubMed Central

    Garrow, Andrew G; Agnew, Alison; Westhead, David R

    2005-01-01

    Background Beta-barrel transmembrane (bbtm) proteins are a functionally important and diverse group of proteins expressed in the outer membranes of bacteria (both gram negative and acid fast gram positive), mitochondria and chloroplasts. Despite recent publications describing reasonable levels of accuracy for discriminating between bbtm proteins and other proteins, screening of entire genomes remains troublesome as these molecules only constitute a small fraction of the sequences screened. Therefore, novel methods are still required capable of detecting new families of bbtm protein in diverse genomes. Results We present TMB-Hunt, a program that uses a k-Nearest Neighbour (k-NN) algorithm to discriminate between bbtm and non-bbtm proteins on the basis of their amino acid composition. By including differentially weighted amino acids, evolutionary information and by calibrating the scoring, an accuracy of 92.5% was achieved, with 91% sensitivity and 93.8% positive predictive value (PPV), using a rigorous cross-validation procedure. A major advantage of this approach is that because it does not rely on beta-strand detection, it does not require resolved structures and thus larger, more representative, training sets could be used. It is therefore believed that this approach will be invaluable in complementing other, physicochemical and homology based methods. This was demonstrated by the correct reassignment of a number of proteins which other predictors failed to classify. We have used the algorithm to screen several genomes and have discussed our findings. Conclusion TMB-Hunt achieves a prediction accuracy level better than other approaches published to date. Results were significantly enhanced by use of evolutionary information and a system for calibrating k-NN scoring. Because the program uses a distinct approach to that of other discriminators and thus suffers different liabilities, we believe it will make a significant contribution to the development of a

  13. Soil erosion and sediment yield, a double barrel problem in South Africa's only large river network without a dam

    NASA Astrophysics Data System (ADS)

    Le Roux, Jay

    2016-04-01

    Soil erosion not only involves the loss of fertile topsoil but is also coupled with sedimentation of dams, a double barrel problem in semi-arid regions where water scarcity is frequent. Due to increasing water requirements in South Africa, the Department of Water and Sanitation is planning water resource development in the Mzimvubu River Catchment, which is the only large river network in the country without a dam. Two dams are planned including a large irrigation dam and a hydropower dam. However, previous soil erosion studies indicate that large parts of the catchment is severely eroded. Previous studies, nonetheless, used mapping and modelling techniques that represent only a selection of erosion processes and provide insufficient information about the sediment yield. This study maps and models the sediment yield comprehensively by means of two approaches over a five-year timeframe between 2007 and 2012. Sediment yield contribution from sheet-rill erosion was modelled with ArcSWAT (a graphical user interface for SWAT in a GIS), whereas gully erosion contributions were estimated using time-series mapping with SPOT 5 imagery followed by gully-derived sediment yield modelling in a GIS. Integration of the sheet-rill and gully results produced a total sediment yield map, with an average of 5 300 t km-2 y-1. Importantly, the annual average sediment yield of the areas where the irrigation dam and hydropower dam will be built is around 20 000 t km-2 y-1. Without catchment rehabilitation, the life expectancy of the irrigation dam and hydropower dam could be 50 and 40 years respectively.

  14. Insulin-Independent GABAA Receptor-Mediated Response in the Barrel Cortex of Mice with Impaired Met Activity

    PubMed Central

    Lo, Fu-Sun; Erzurumlu, Reha S.

    2016-01-01

    Autism spectrum disorder (ASD) is a neurodevelopmental disorder caused by genetic variants, susceptibility alleles, and environmental perturbations. The autism associated gene MET tyrosine kinase has been implicated in many behavioral domains and endophenotypes of autism, including abnormal neural signaling in human sensory cortex. We investigated somatosensory thalamocortical synaptic communication in mice deficient in Met activity in cortical excitatory neurons to gain insights into aberrant somatosensation characteristic of ASD. The ratio of excitation to inhibition is dramatically increased due to decreased postsynaptic GABAA receptor-mediated inhibition in the trigeminal thalamocortical pathway of mice lacking active Met in the cerebral cortex. Furthermore, in contrast to wild-type mice, insulin failed to increase GABAA receptor-mediated response in the barrel cortex of mice with compromised Met signaling. Thus, lacking insulin effects may be a risk factor in ASD pathogenesis. SIGNIFICANCE STATEMENT A proposed common cause of neurodevelopmental disorders is an imbalance in excitatory neural transmission, provided by the glutamatergic neurons, and the inhibitory signals from the GABAergic interneurons. Many genes associated with autism spectrum disorders impair synaptic transmission in the expected cell type. Previously, inactivation of the autism-associated Met tyrosine kinase receptor in GABAergic interneurons led to decreased inhibition. In thus report, decreased Met signaling in glutamatergic neurons had no effect on excitation, but decimated inhibition. Further experiments indicate that loss of Met activity downregulates GABAA receptors on glutamatergic neurons in an insulin independent manner. These data provide a new mechanism for the loss of inhibition and subsequent abnormal excitation/inhibition balance and potential molecular candidates for treatment or prevention. PMID:27030755

  15. Evaluation of time-dose and fractionation for sup 252 Cf neutrons in preoperative bulky/barrel-cervix carcinoma radiotherapy

    SciTech Connect

    Maruyama, Y.; Wierzbicki, J. )

    1990-12-01

    Time-dose fractionation factors (TDF) were calculated for 252Cf (Cf) neutron therapy versus 137Cs for intracavitary use in the preoperative treatment of bulky/barrel-shaped Stage IB cervix cancers. The endpoint assessed was gross and microscopic tumor eradication from the hysterectomy specimen. We reviewed the data obtained in clinical trials between 1976-1987 at the University of Kentucky Medical Center. Preoperative photon therapy was approximately 45 Gy of whole pelvis irradiation in 5 weeks for both 137Cs and Cf treated patients. 137Cs implant was done after pelvic irradiation x1 to a mean dose of 2104 +/- 36 cGy at point A at a dose rate of 50.5 cGy/h. There were 37.5% positive specimens. Using Cf intracavitary implants, dose varied from 109 to 459 neutron cGy in 1-2 sessions. Specimens were more frequently cleared of tumor (up to 100% at appropriate dose) and showed a dose-response relationship, both by nominal dose and by TDF adjusted analysis of dose, dose-rate, number of sessions, and overall time. Limited understanding of relative biological effectiveness, schedule, effect of implants, and dose rate all made it difficult to use TDF to study neutron effects. Relative biological effectiveness (RBE) was estimated and showed that for Cf, RBE was a complex function of treatment variables. In the pilot clinical studies, a value of 6.0 had been assumed. The present findings of RBE for tumor destruction are larger than those assumed. Cf was effective for cervix tumor therapy and produced control without significant side effects due to the brachytherapy method used. The TDF model was of limited value in the present analysis and more information is still needed for RBE, dose-rate, and fractionation effects for Cf neutrons to develop a more sophisticated and relevant model.

  16. RX-26-AY/AF rifle bullet tests

    SciTech Connect

    Sharp, D.D.

    1980-11-01

    A series of rifle bullet tests was performed on two explosives, RX-26-AY and RX-26-AF, using the Pantex version of the Picatinny Arsenal Test (PA-2). With the exception of one test, both explosives displayed a relatively low sensitivity to bullet impact. However, a marked difference was noted in the average burn time duration between the two types of explosives being tested. A minor modification was made on the rifle barrel used at the test site in order to improve the sighting procedure.

  17. The Borrelia afzelii outer membrane protein BAPKO_0422 binds human factor-H and is predicted to form a membrane-spanning β-barrel

    PubMed Central

    Dyer, Adam; Brown, Gemma; Stejskal, Lenka; Laity, Peter R.; Bingham, Richard J.

    2015-01-01

    The deep evolutionary history of the Spirochetes places their branch point early in the evolution of the diderms, before the divergence of the present day Proteobacteria. As a spirochete, the morphology of the Borrelia cell envelope shares characteristics of both Gram-positive and Gram-negative bacteria. A thin layer of peptidoglycan, tightly associated with the cytoplasmic membrane, is surrounded by a more labile outer membrane (OM). This OM is rich in lipoproteins but with few known integral membrane proteins. The outer membrane protein A (OmpA) domain is an eight-stranded membrane-spanning β-barrel, highly conserved among the Proteobacteria but so far unknown in the Spirochetes. In the present work, we describe the identification of four novel OmpA-like β-barrels from Borrelia afzelii, the most common cause of erythema migrans (EM) rash in Europe. Structural characterization of one these proteins (BAPKO_0422) by SAXS and CD indicate a compact globular structure rich in β-strand consistent with a monomeric β-barrel. Ab initio molecular envelopes calculated from the scattering profile are consistent with homology models and demonstrate that BAPKO_0422 adopts a peanut shape with dimensions 25×45 Å (1 Å=0.1 nm). Deviations from the standard C-terminal signature sequence are apparent; in particular the C-terminal phenylalanine residue commonly found in Proteobacterial OM proteins is replaced by isoleucine/leucine or asparagine. BAPKO_0422 is demonstrated to bind human factor H (fH) and therefore may contribute to immune evasion by inhibition of the complement response. Encoded by chromosomal genes, these proteins are highly conserved between Borrelia subspecies and may be of diagnostic or therapeutic value. PMID:26181365

  18. Report of Findings: Lake Superior Classified Barrel Disposal Site. Defense Environmental Restoration Program for Formerly Used Defense Sites. Project No. E05MN025501

    DTIC Science & Technology

    1991-08-01

    either melting or operation in i9s " those barrels is medium carbon ste water dumping. (It was-,Ed.) and maybe some aluminum shaving" A blast funace was...Material involved was: " Ceramic . Concrete . Impregnated " Magnesium . Steel Paper/ Fiber - " Brass . Aluminum glass Tape Due to the lapsed time :and...airli,.Wsym v filg. rinmum". enuase of asbesft fibers back into tileswon ugi thatf -~rs repam- lake win the onmloo disposl, ate is azse& we In lin gov

  19. A conserved tryptophan (W91) at the barrel-lid junction modulates the packing and stability of Kunitz (STI) family of inhibitors.

    PubMed

    Majumder, Sudip; Khamrui, Susmita; Banerjee, Ramanuj; Bhowmik, Pallab; Sen, Udayaditya

    2015-01-01

    β-trefoil fold, consisting of a six stranded β-barrel capped at one end by a lid comprising of another six β-strands, is one of the most important folds among proteins. Important classes of proteins like Interleukins (ILs), Fibroblast Growth Factors (FGFs), Kunitz (STI) family of inhibitors etc. belong to this fold. Their core is packed by hydrophobic residues contributed by the 6 stranded β-barrel and three β-hairpins that make essential contacts with each other and keep the protein in 'topologically minimal frustrated state'. A complete database analysis of the core residues of the β-trefoil fold proteins presented here identified a conserved tryptophan (W91) residue in the Kunitz (STI) family of inhibitors that projects from the lid and interacts with the bottom layer residues of the barrel. This kind of interactions is unique in Kunitz (STI) family because no other families of β-trefoil fold have such a shear sized residue at the barrel lid junction; suggesting its possible importance in packing and stability. We took WCI as a representative of this family and prepared four cavity creating mutants W91F-WCI, W91M-WCI, W91I-WCI & W91A-WCI. CD experiments show that the secondary structure of the mutants remains indistinguishable with the wild type. Crystal structures of the mutants W91F-WCI, W91M-WCI & W91A-WCI also show the same feature. However, slight readjustments of the side chains around the site of mutation have been observed so as to minimize the cavity created due to mutation. Comparative stability of these mutants, estimated using heat denaturation CD spectroscopy, indicates that stability of the mutants inversely correlates with the size of the cavity inside the core. Interestingly, although we mutated at the core, mutants show varying susceptibility against tryptic digestion that grossly follow their instability determined by CD. Our findings suggest that the W91 residue plays an important role in determining the stability and packing of the

  20. Advanced Manufacturing Technologies (AMT): Additive Manufactured Hot Fire Planning and Testing in GRC Cell 32 Project

    NASA Technical Reports Server (NTRS)

    Fikes, John C.

    2014-01-01

    The objective of this project is to hot fire test an additively manufactured thrust chamber assembly TCA (injector and thrust chamber). GRC will install the additively manufactured Inconel 625 injector, two additively manufactured (SLM) water cooled Cu-Cr thrust chamber barrels and one additively manufactured (SLM) water cooled Cu-Cr thrust chamber nozzle on the test stand in Cell 32 and perform hot fire testing of the integrated TCA.

  1. pH-induced conformational change of the beta-barrel-forming protein OmpG reconstituted into native E. coli lipids.

    PubMed

    Mari, Stefania A; Köster, Stefan; Bippes, Christian A; Yildiz, Ozkan; Kühlbrandt, Werner; Muller, Daniel J

    2010-02-26

    A gating mechanism of the beta-barrel-forming outer membrane protein G (OmpG) from Escherichia coli was recently presented. The mechanism was based on X-ray structures revealed from crystals grown from solubilized OmpG at both neutral pH and acidic pH. To investigate whether these conformations represent the naturally occurring gating mechanism, we reconstituted OmpG in native E. coli lipids and applied high-resolution atomic force microscopy. The reconstituted OmpG molecules assembled into both monomers and dimers. Single monomeric and dimeric OmpG molecules showed open channel entrances at pH 7.5 and at room temperature. The extracellular loops connecting the beta-strands that form the transmembrane beta-barrel pore exhibited elevated structural flexibility. Upon lowering the pH to 5.0, the conformation of OmpG molecules changed to close the extracellular entrance of their channel. It appears that one or more of the extracellular loops collapsed onto the channel entrance. This conformational change was fully reversible. Our data confirm that the previously reported gating mechanism of OmpG occurs at physiological conditions in E. coli lipid membranes.

  2. Low molecular weight oligomers of amyloid peptides display β-barrel conformations: A replica exchange molecular dynamics study in explicit solvent

    NASA Astrophysics Data System (ADS)

    De Simone, Alfonso; Derreumaux, Philippe

    2010-04-01

    The self-assembly of proteins and peptides into amyloid fibrils is connected to over 40 pathological conditions including neurodegenerative diseases and systemic amyloidosis. Diffusible, low molecular weight protein and peptide oligomers that form in the early steps of aggregation appear to be the harmful cytotoxic species in the molecular etiology of these diseases. So far, the structural characterization of these oligomers has remained elusive owing to their transient and dynamic features. We here address, by means of full atomistic replica exchange molecular dynamics simulations, the energy landscape of heptamers of the amyloidogenic peptide NHVTLSQ from the beta-2 microglobulin protein. The simulations totaling 5 μs show that low molecular weight oligomers in explicit solvent consist of β-barrels in equilibrium with amorphous states and fibril-like assemblies. The results, also accounting for the influence of the pH on the conformational properties, provide a strong evidence of the formation of transient β-barrel assemblies in the early aggregation steps of amyloid-forming systems. Our findings are discussed in terms of oligomers cytotoxicity.

  3. Low molecular weight oligomers of amyloid peptides display beta-barrel conformations: a replica exchange molecular dynamics study in explicit solvent.

    PubMed

    De Simone, Alfonso; Derreumaux, Philippe

    2010-04-28

    The self-assembly of proteins and peptides into amyloid fibrils is connected to over 40 pathological conditions including neurodegenerative diseases and systemic amyloidosis. Diffusible, low molecular weight protein and peptide oligomers that form in the early steps of aggregation appear to be the harmful cytotoxic species in the molecular etiology of these diseases. So far, the structural characterization of these oligomers has remained elusive owing to their transient and dynamic features. We here address, by means of full atomistic replica exchange molecular dynamics simulations, the energy landscape of heptamers of the amyloidogenic peptide NHVTLSQ from the beta-2 microglobulin protein. The simulations totaling 5 micros show that low molecular weight oligomers in explicit solvent consist of beta-barrels in equilibrium with amorphous states and fibril-like assemblies. The results, also accounting for the influence of the pH on the conformational properties, provide a strong evidence of the formation of transient beta-barrel assemblies in the early aggregation steps of amyloid-forming systems. Our findings are discussed in terms of oligomers cytotoxicity.

  4. Integron-associated mobile gene cassettes code for folded proteins: the structure of Bal32a, a new member of the adaptable alpha+beta barrel family.

    PubMed

    Robinson, Andrew; Wu, Peter S-C; Harrop, Stephen J; Schaeffer, Patrick M; Dosztányi, Zsuzsanna; Gillings, Michael R; Holmes, Andrew J; Nevalainen, K M Helena; Stokes, H W; Otting, Gottfried; Dixon, Nicholas E; Curmi, Paul M G; Mabbutt, Bridget C

    2005-03-11

    The wide-ranging physiology and large genetic variability observed for prokaryotes is largely attributed, not to the prokaryotic genome itself, but rather to mechanisms of lateral gene transfer. Cassette PCR has been used to sample the integron/gene cassette metagenome from different natural environments without laboratory cultivation of the host organism, and without prior knowledge of any target protein sequence. Since over 90% of cassette genes are unrelated to any sequence in the current databases, it is not clear whether these genes code for folded functional proteins. We have selected a sample of eight cassette-encoded genes with no known homologs; five have been isolated as soluble protein products and shown by biophysical techniques to be folded. In solution, at least three of these proteins organise as stable oligomeric assemblies. The tertiary structure of one of these, Bal32a derived from a contaminated soil site, has been solved by X-ray crystallography to 1.8 A resolution. From the three-dimensional structure, Bal32a is found to be a member of the highly adaptable alpha+beta barrel family of transport proteins and enzymes. In Bal32a, the barrel cavity is unusually deep and inaccessible to solvent. Polar side-chains in its interior are reminiscent of catalytic sites of limonene-1,2-epoxide hydrolase and nogalonic acid methyl ester cyclase. These studies demonstrate the viability of direct sampling of mobile DNA as a route for the discovery of novel proteins.

  5. The time course of activity-regulated cytoskeletal (ARC) gene and protein expression in the whisker-barrel circuit using two paradigms of whisker stimulation.

    PubMed

    Khodadad, Aida; Adelson, P David; Lifshitz, Jonathan; Thomas, Theresa Currier

    2015-05-01

    Immediate early genes have previously demonstrated a rapid increase in gene expression after various behavioral paradigms. The main focus of this article is to identify a molecular marker of circuit activation after manual whisker stimulation or exploration of a novel environment. To this end, we investigated the dynamics of ARC transcription in adult male rats during whisker somatosensation throughout the whisker barrel circuit. At various time points, tissue was biopsied from the ventral posterior medial nucleus (VPM) of the thalamus, primary somatosensory barrel field (S1BF) cortex and hippocampus for quantification using real-time PCR and western blot. Our results show that there were no significant differences in ARC gene or protein expression in the VPM after both types of stimulation. However, manual whisker stimulation resulted in increased ARC gene expression at 15, 30, 60 and 300 min in the S1BF, and 15 min in the hippocampus (p<0.05). Also, exploration of a novel environment resulted in increased ARC mRNA expression at 15 and 30 min in the S1BF and at 15 min in the hippocampus (p<0.05). The type of stimulation (manual versus exploration of a novel environment) influenced the magnitude of ARC gene expression in the S1BF (p<0.05). These data are the first to demonstrate that ARC is a specific, quantifiable and input dependent molecular marker of circuit activation which can serve to quantify the impact of brain injury and subsequent rehabilitation on whisker sensation.

  6. Public health assessment for tri-cities Barrel Company, Inc. , Fenton, Broome County, New York, Region 2. CERCLIS No. NYD980509285. Preliminary report

    SciTech Connect

    Not Available

    1993-03-18

    The Tri-Cities Barrel Company, Inc., facility was included on the original New York State Registry of Hazardous Waste Sites in June 1980 when it was discovered that hazardous waste had been discharged to ground surface and to unlined lagoons. This site was later placed on the National Priorities List (NPL). Four monitoring wells were drilled and sampled during a preliminary site investigation. The on-site contamination of groundwater was documented by sampling of monitoring wells in 1986. One private well near the site showed low levels of ethylbenzene, meta-xylene and ortho-xylene; it is not clear, however, if this was related to the site. A second sample was taken from this well in 1990 and did not detect any contaminants. Since the preliminary report, additional waste lagoons have been identified and the site was expanded to include the entire 13 acres owned by the Tri-Cities Barrel Company. A remedial investigation is currently ongoing. Based on information reviewed, this site is an indeterminate public health hazard because the extent of contamination in groundwater has not been defined and contamination in areas north of I-88 has not been confirmed or defined. The primary health concern associated with exposure to chemicals at the site comes from their potential to cause cancer in humans or animals.

  7. Double-barrel Y-configuration Stenting for Flow Diversion of a Giant Recurrent Basilar Apex Aneurysm with the Pipeline Flex Embolization Device

    PubMed Central

    Ding, Dale; Starke, Robert M.; McGuinness, Ben; Brew, Stefan

    2016-01-01

    Giant basilar apex aneurysms are extremely challenging to successfully manage. The Pipeline Flex embolization device (PFED) is a new generation flow-diverting stent with a modified delivery system which allows resheathing of the stent after partial deployment. We describe a case of double-barrel Y-configuration stenting of a giant, recurrent basilar apex aneurysm using the PFED. A 73-year-old male was previously treated for an unruptured 11-mm basilar apex aneurysm with stent-assisted coiling using a Neuroform stent. The aneurysm was retreated twice with repeat coiling. After the third recurrence and persistent aneurysm growth into a giant, symptomatic lesion, we decided to proceed with flow diversion. We performed Y-stenting of the basilar bifurcation using three PFEDs, and was recoiled the aneurysm sac. Due to the low porosity of the flow diverters, a side-by-side double-barrel configuration was necessary in the basilar artery. Without the PFED's resheathable capability, it would not have been possible to perform Y-stenting with flow diverters. PMID:28163518

  8. Double-barrel Y-configuration Stenting for Flow Diversion of a Giant Recurrent Basilar Apex Aneurysm with the Pipeline Flex Embolization Device.

    PubMed

    Ding, Dale; Starke, Robert M; McGuinness, Ben; Brew, Stefan

    2016-12-01

    Giant basilar apex aneurysms are extremely challenging to successfully manage. The Pipeline Flex embolization device (PFED) is a new generation flow-diverting stent with a modified delivery system which allows resheathing of the stent after partial deployment. We describe a case of double-barrel Y-configuration stenting of a giant, recurrent basilar apex aneurysm using the PFED. A 73-year-old male was previously treated for an unruptured 11-mm basilar apex aneurysm with stent-assisted coiling using a Neuroform stent. The aneurysm was retreated twice with repeat coiling. After the third recurrence and persistent aneurysm growth into a giant, symptomatic lesion, we decided to proceed with flow diversion. We performed Y-stenting of the basilar bifurcation using three PFEDs, and was recoiled the aneurysm sac. Due to the low porosity of the flow diverters, a side-by-side double-barrel configuration was necessary in the basilar artery. Without the PFED's resheathable capability, it would not have been possible to perform Y-stenting with flow diverters.

  9. Effect of the aging on lees and other alternative techniques on the low molecular weight phenols of Tempranillo red wine aged in oak barrels.

    PubMed

    Del Barrio-Galán, Rubén; Pérez-Magariño, Silvia; Ortega-Heras, Miriam

    2012-06-30

    The effect of different alternative techniques to the traditional aging on lees on the low molecular weight phenolic compounds of red wines was study as well as their evolution during the aging in oak wood barrels for six months. The study was carried out with Tempranillo red grapes from two consecutive vintages. The techniques assayed were the traditional aging on lees with or without the addition of exogenous β-glucanase enzymes, the use of yeast derivative preparations also with or without the addition of exogenous β-glucanase enzymes, the micro-oxygenation applied together with the aging on lees, and the use of non-toasted oak wood chips. Hydroxycinnamic acids were the compounds most affected by these treatments, mainly in the wines treated with chips and commercial yeast derivative products, which showed higher concentrations of the free acids, compounds that play an important role in wine stabilization color since they can act as anthocyanin copigments. The differences found between the assayed treatments were more important in the 2007 vintage than in the 2008. However, a more significant effect of micro-oxygenation in the 2008 vintage was observed, which could be related to the fact that in this vintage the treatment was longer. In the 2008 vintage, the differences between treatments decreased along the aging in barrel. This vintage effect could be associated to the differences in the phenolic concentration of the initial wines. In this sense more research should be done to corroborate this fact.

  10. Phase II clinical trial using californium 252 fast neutron brachytherapy, external pelvic radiation, and extrafascial hysterectomy in the treatment of bulky, barrel-shaped stage IB cervical cancer.

    PubMed

    van Nagell, J R; Maruyama, Y; Donaldson, E S; Hanson, M B; Gallion, H H; Yoneda, J; Powell, D E; Kryscio, R J; Beach, J L

    1986-05-15

    From June 1977 to June 1983, 32 patients with bulky (greater than 4 cm diameter), barrel-shaped Stage IB cervical cancer were treated at the University of Kentucky Medical Center by a combination of outpatient neutron brachytherapy using californium 252 (252Cf) and external pelvic radiation followed by extrafascial hysterectomy. Nineteen patients had cervical tumors 4 to 6 cm in diameter, and 13 patients had lesions in excess of 6 cm in diameter. A dose of 4500 rad external photon therapy was given from a linear accelerator, and one or two 6-hour 252Cf implants were given during or immediately after external radiation. Extrafascial hysterectomy with bilateral salpingo-oophorectomy was performed 6 weeks after completion of radiation therapy. Complications during and after radiation were minimal and included vaginal stenosis (three) and proctitis (two). Tumor clearance in the hysterectomy specimen was complete in 23 patients (72%) and residual cervical tumor was present in 9 patients (28%). Two patients developed tumor recurrence and died of disease 15 and 27 months after therapy, respectively. Thirty patients remain free of disease 26 to 96 months (median, 52 months) after treatment, and none have been lost to follow-up. The actuarial survival of these patients is 97% at 2 years and 94% at 5 years. Intracavitary neutron therapy is well tolerated and is effective when combined with external radiation and hysterectomy in the treatment of bulky, barrel-shaped Stage IB cervical cancer.

  11. Attenuated sensory deprivation-induced changes of parvalbumin neuron density in the barrel cortex of FcγRllB-deficient mice.

    PubMed

    Watanabe, Makiko; Ueno, Hiroshi; Suemitsu, Shunsuke; Yokobayashi, Eriko; Matsumoto, Yosuke; Usui, Shinichi; Sujiura, Hiroko; Okamoto, Motoi

    2012-01-01

    Recent studies have demonstrated the important role of immune molecules in the development of neuronal circuitry and synaptic plasticity. We have detected the presence of FcγRllB protein in parvalbumin-containing inhibitory interneurons (PV neurons). In the present study, we examined the appearance of PV neurons in the barrel cortex and the effect of sensory deprivation in FcγRllB-deficient mice (FcγRllB-/-) and wild-type mice. There was no substantial difference in the appearance of PV neurons in the developing barrel cortex between FcγRllB-/- and wild-type mice. Sensory deprivation from immediately after birth (P0) or P7 to P12-P14 induced an increase in PV neurons. In contrast, sensory deprivation from P7 or P14 to P28, but not from P21 to P28, decreased PV neurons in wild-type mice. However, sensory deprivation from P0 or P7 to P12-P14 did not increase PV neurons and sensory deprivation from P7 or P14 to P28 did not decrease or only modestly decreased PV neurons in FcγRllB-/- mice. The results indicate that expression of PV is regulated by sensory experience and the second and third postnatal weeks are a sensitive period for sensory deprivation, and suggest that FcγRllB contributes to sensory experience-regulated expression of PV.

  12. Volatile compounds as markers of ageing in Tempranillo red wines from La Mancha D.O. stored in oak wood barrels.

    PubMed

    Castro-Vázquez, Lucía; Alañón, M Elena; Calvo, Elena; Cejudo, M Jesús; Díaz-Maroto, M Consuelo; Pérez-Coello, M Soledad

    2011-07-29

    Solid-phase extraction cartridges (SPE)-GC/MS method was used to analyse red wines aromas. The matrix effect was studied with chemicals standard prepared in synthetic wines with water/alcohol solutions (12% ethanol, v/v) following the procedure proposed. The method offers good reproducibility since the relative standard deviations (RSD%) for the volatile compounds levels were less than 9%. This method was used to differentiate the aroma of one hundred mono-varietal young, crianza, reserva and gran reserva La Mancha D.O. wines (cv. Tempranillo) on the basis of oak barrel contact period. Samples were checked at ten time points over 36 months. Sixty important wine odorants, such as volatile phenols, vanillin derivatives, lactones, norisoprenoids, benzene compounds, esters and terpenols, can be quantitatively determined in a single run. Results showed significant quantitative differences in the volatile profiles of wines depending on the length of time in contact with wood, even in wines belonging to the same commercial category. Stepwise multiple linear regression (SMLR) was used to obtain a model that predicted the time of barrel ageing to which wines were submitted in relation with the wine volatile composition. A successful function based on eight compounds with a mean deviation of 0.37 months in the predictions, was obtained.

  13. The Structure of a BamA-BamD Fusion Illuminates the Architecture of the β-Barrel Assembly Machine Core.

    PubMed

    Bergal, Hans Thor; Hopkins, Alex Hunt; Metzner, Sandra Ines; Sousa, Marcelo Carlos

    2016-02-02

    The β-barrel assembly machine (BAM) mediates folding and insertion of integral β-barrel outer membrane proteins (OMPs) in Gram-negative bacteria. Of the five BAM subunits, only BamA and BamD are essential for cell viability. Here we present the crystal structure of a fusion between BamA POTRA4-5 and BamD from Rhodothermus marinus. The POTRA5 domain binds BamD between its tetratricopeptide repeats 3 and 4. The interface structural elements are conserved in the Escherichia coli proteins, which allowed structure validation by mutagenesis and disulfide crosslinking in E. coli. Furthermore, the interface is consistent with previously reported mutations that impair BamA-BamD binding. The structure serves as a linchpin to generate a BAM model where POTRA domains and BamD form an elongated periplasmic ring adjacent to the membrane with a central cavity approximately 30 × 60 Å wide. We propose that nascent OMPs bind this periplasmic ring prior to insertion and folding by BAM.

  14. Esthetic and functional reconstruction of the posttumoral interrupted mandible with double-barrel fibular free flap graft: rationale for a microsurgical and prosthodontic approach.

    PubMed

    Paranque, Armand-Régis; Steve, Marc; Vazquez, Lydia; Bolleyn, Alain; Roze-Pellat, Marie-Andrée; Dohan Ehrenfest, David M

    2011-10-01

    Reconstruction after substantial osseous, cutaneous, and muscular tissue loss following a mandibular resection is a challenge. The use of a fibular free flap is an outstanding, but delicate, treatment option. These grafts, using the double-barrel technique, can achieve an almost complete reconstruction of the mandibular defect. The challenge posed by these treatments is to achieve an end result that is both functional and esthetically pleasing-an endeavor that requires a defined prosthetic plan prior to complete microsurgical reconstruction. Using a detailed clinical case, this article discusses the importance of planning the mandible reconstruction with double-barrel fibular graft in view of an implant-supported fixed partial denture. Immediate implant loading was even possible in this case. This approach allows improvement of the final esthetic and functional result of such a complex rehabilitation. Maxillofacial reconstructive surgery should seek to establish a near-as-normal anatomic situation that will allow a permanent implant rehabilitation that is both esthetic and durable.

  15. Test report -- Prototype core sampler

    SciTech Connect

    Linschooten, C.G.

    1995-01-17

    The purpose of this test is to determine the adequacy of the prototype sampler, provided to Westinghouse Hanford Company (WHC) by DOE-RL. The sampler was fabricated for DOE-RL by the Concord Company by request of DOE-RL. This prototype sampler was introduced as a technology that can be easily deployed (similar to the current auger system) and will reliably collect representative samples. The sampler is similar to the Universal Sampler i.e., smooth core barrel and piston with an O-ring seal, but lacks a rotary valve near the throat of the sampler. This makes the sampler inappropriate for liquid sampling, but reduces the outside diameter of the sampler considerably, which should improve sample recovery. Recovery testing was performed with the supplied sampler in three different consistencies of Kaolin sludge simulants.

  16. Single-Cylinder Engine Tests of Porous Chrome-Plated Cylinder Barrels with Special Bore Coatings for Radial Air-Cooled Engines

    DTIC Science & Technology

    1946-01-01

    sulphamate solution at room temperature having a hydrogen-ion concentration of 1.5. The cylinder was plated for 2 minutes with a current density of 40...for any metal combination (reference 3), engine friction may be reduced somewhat by the use of a silver overplate as a bearing material on the...Cooled Engines. NACA ARR No. E5L18, 1945. 3. Hoyt, Samuel L.: Metals and Alloys Data Book. Reinhold Pub. Corp., 1943, p. 281. 4. Downing, B. F

  17. Recurring sequence-structure motifs in (βα)8-barrel proteins and experimental optimization of a chimeric protein designed based on such motifs.

    PubMed

    Wang, Jichao; Zhang, Tongchuan; Liu, Ruicun; Song, Meilin; Wang, Juncheng; Hong, Jiong; Chen, Quan; Liu, Haiyan

    2017-02-01

    An interesting way of generating novel artificial proteins is to combine sequence motifs from natural proteins, mimicking the evolutionary path suggested by natural proteins comprising recurring motifs. We analyzed the βα and αβ modules of TIM barrel proteins by structure alignment-based sequence clustering. A number of preferred motifs were identified. A chimeric TIM was designed by using recurring elements as mutually compatible interfaces. The foldability of the designed TIM protein was then significantly improved by six rounds of directed evolution. The melting temperature has been improved by more than 20°C. A variety of characteristics suggested that the resulting protein is well-folded. Our analysis provided a library of peptide motifs that is potentially useful for different protein engineering studies. The protein engineering strategy of using recurring motifs as interfaces to connect partial natural proteins may be applied to other protein folds.

  18. Exploration of material removal rate of srf elliptical cavities as a function of media type and cavity shape on niobium and copper using centrifugal barrel polishing (cbp)

    SciTech Connect

    Palczewski, Ari; Ciovati, Gianluigi; Li, Yongming; Geng, Rongli

    2013-09-01

    Centrifugal barrel polishing (cbp) for SRF application is becoming more wide spread as the technique for cavity surface preparation. CBP is now being used in some form at SRF laboratories around the world including in the US, Europe and Asia. Before the process can become as mature as wet chemistry like eletro-polishing (EP) and buffered chemical polishing (BCP) there are many questions which remain unanswered. One of these topics includes the uniformity of removal as a function of cavity shape and material type. In this presentation we show CBP removal rates for various media types on 1.3 GHz TESLA and 1.5 GHz CEBAF large/fine grain niobium cavities, and 1.3GHz low surface field copper cavity. The data will also include calculated RF frequency shift modeling non-uniform removal as a function of cavity position and comparing them with CBP results.

  19. Inherent chaperone-like activity of aspartic proteases reveals a distant evolutionary relation to double-ψ barrel domains of AAA-ATPases

    PubMed Central

    Hulko, Michael; Lupas, Andrei N.; Martin, Jörg

    2007-01-01

    Chaperones and proteases share the ability to interact with unfolded proteins. Here we show that enzymatically inactive forms of the aspartic proteases HIV-1 protease and pepsin have inherent chaperone-like activity and can prevent the aggregation of denatured substrate proteins. In contrast to proteolysis, which requires dimeric enzymes, chaperone-like activity could be observed also with monomeric domains. The involvement of the active site cleft in the chaperone-like function was demonstrated by the inhibitory effect of peptide substrate inhibitors. The high structural similarity between aspartic proteases and the N-terminal double-ψ barrels of Cdc48-like proteins, which are involved in the unfolding and dissociation of proteins, suggests that they share a common ancestor. The latent chaperone-like activity in aspartic proteases can be seen as a relic that has further evolved to serve substrate binding in the context of proteolytic activity. PMID:17384229

  20. Conformational sampling and structure prediction of multiple interacting loops in soluble and β-barrel membrane proteins using multi-loop distance-guided chain-growth Monte Carlo method

    PubMed Central

    Tang, Ke; Wong, Samuel W.K.; Liu, Jun S.; Zhang, Jinfeng; Liang, Jie

    2015-01-01

    Motivation: Loops in proteins are often involved in biochemical functions. Their irregularity and flexibility make experimental structure determination and computational modeling challenging. Most current loop modeling methods focus on modeling single loops. In protein structure prediction, multiple loops often need to be modeled simultaneously. As interactions among loops in spatial proximity can be rather complex, sampling the conformations of multiple interacting loops is a challenging task. Results: In this study, we report a new method called multi-loop Distance-guided Sequential chain-Growth Monte Carlo (M-DiSGro) for prediction of the conformations of multiple interacting loops in proteins. Our method achieves an average RMSD of 1.93 Å for lowest energy conformations of 36 pairs of interacting protein loops with the total length ranging from 12 to 24 residues. We further constructed a data set containing proteins with 2, 3 and 4 interacting loops. For the most challenging target proteins with four loops, the average RMSD of the lowest energy conformations is 2.35 Å. Our method is also tested for predicting multiple loops in β-barrel membrane proteins. For outer-membrane protein G, the lowest energy conformation has a RMSD of 2.62 Å for the three extracellular interacting loops with a total length of 34 residues (12, 12 and 10 residues in each loop). Availability and implementation: The software is freely available at: tanto.bioe.uic.edu/m-DiSGro. Contact: jinfeng@stat.fsu.edu or jliang@uic.edu Supplementary information: Supplementary data are available at Bioinformatics online. PMID:25861965

  1. Enhanced triterpene saponin biosynthesis and root nodulation in transgenic barrel medic (Medicago truncatula Gaertn.) expressing a novel beta-amyrin synthase (AsOXA1) gene.

    PubMed

    Confalonieri, Massimo; Cammareri, Maria; Biazzi, Elisa; Pecchia, Paola; Fevereiro, Manuel Pedro Salema; Balestrazzi, Alma; Tava, Aldo; Conicella, Clara

    2009-02-01

    Triterpene saponins are a group of bioactive compounds abundant in the genus Medicago, and have been studied extensively for their biological and pharmacological properties. In this article, we evaluated the effects of the ectopic expression of AsOXA1 cDNA from Aster sedifolius on the production of triterpene saponins in barrel medic (Medicago truncatula Gaertn.). AsOXA1 cDNA encodes beta-amyrin synthase, a key enzyme involved in triterpene saponin biosynthesis. One of the four transgenic lines expressing AsOXA1 accumulated significantly larger amounts of some triterpenic compounds in leaf and root than did control plants. In particular, the leaf exhibited significantly higher levels of bayogenin, medicagenic acid and zanhic acid. The amounts of medicagenic acid and zanhic acid, which represent the core of the M. truncatula leaf saponins, were 1.7 and 2.1 times higher, respectively, than the amounts extracted from the control line. In root, the production of bayogenin, hederagenin, soyasapogenol E and 2beta-hydroxyoleanolic acid was increased significantly. The increase in the total amounts of triterpenic compounds observed in the leaves of transgenic lines correlated with the AsOXA1 expression level. Interestingly, the plants expressing AsOXA1 showed, under different growth conditions, improved nodulation when compared with the control line. Nodulation enhancement was also accompanied by a significant change in the soyasapogenol B content. Our results indicate that the ectopic expression of AsOXA1 in barrel medic leads to a greater accumulation of triterpene saponins and enhanced root nodulation.

  2. Analysis of mutations in Neurospora crassa ERMES components reveals specific functions related to β-barrel protein assembly and maintenance of mitochondrial morphology.

    PubMed

    Wideman, Jeremy G; Lackey, Sebastian W K; Srayko, Martin A; Norton, Kacie A; Nargang, Frank E

    2013-01-01

    The endoplasmic reticulum mitochondria encounter structure (ERMES) tethers the er to mitochondria and contains four structural components: Mmm1, Mdm12, Mdm10, and Mmm2 (Mdm34). The Gem1 protein may play a role in regulating ERMES function. Saccharomyces cerevisiae and Neurospora crassa strains lacking any of Mmm1, Mdm12, or Mdm10 are known to show a variety of phenotypic defects including altered mitochondrial morphology and defects in the assembly of β-barrel proteins into the mitochondrial outer membrane. Here we examine ERMES complex components in N. crassa and show that Mmm1 is an ER membrane protein containing a Cys residue near its N-terminus that is conserved in the class Sordariomycetes. The residue occurs in the ER-lumen domain of the protein and is involved in the formation of disulphide bonds that give rise to Mmm1 dimers. Dimer formation is required for efficient assembly of Tom40 into the TOM complex. However, no effects are seen on porin assembly or mitochondrial morphology. This demonstrates a specificity of function and suggests a direct role for Mmm1 in Tom40 assembly. Mutation of a highly conserved region in the cytosolic domain of Mmm1 results in moderate defects in Tom40 and porin assembly, as well as a slight morphological phenotype. Previous reports have not examined the role of Mmm2 with respect to mitochondrial protein import and assembly. Here we show that absence of Mmm2 affects assembly of β-barrel proteins and that lack of any ERMES structural component results in defects in Tom22 assembly. Loss of N. crassa Gem1 has no effect on the assembly of these proteins but does affect mitochondrial morphology.

  3. Bipartite Topology of Treponema pallidum Repeat Proteins C/D and I: OUTER MEMBRANE INSERTION, TRIMERIZATION, AND PORIN FUNCTION REQUIRE A C-TERMINAL β-BARREL DOMAIN.

    PubMed

    Anand, Arvind; LeDoyt, Morgan; Karanian, Carson; Luthra, Amit; Koszelak-Rosenblum, Mary; Malkowski, Michael G; Puthenveetil, Robbins; Vinogradova, Olga; Radolf, Justin D

    2015-05-08

    We previously identified Treponema pallidum repeat proteins TprC/D, TprF, and TprI as candidate outer membrane proteins (OMPs) and subsequently demonstrated that TprC is not only a rare OMP but also forms trimers and has porin activity. We also reported that TprC contains N- and C-terminal domains (TprC(N) and TprC(C)) orthologous to regions in the major outer sheath protein (MOSP(N) and MOSP(C)) of Treponema denticola and that TprC(C) is solely responsible for β-barrel formation, trimerization, and porin function by the full-length protein. Herein, we show that TprI also possesses bipartite architecture, trimeric structure, and porin function and that the MOSP(C)-like domains of native TprC and TprI are surface-exposed in T. pallidum, whereas their MOSP(N)-like domains are tethered within the periplasm. TprF, which does not contain a MOSP(C)-like domain, lacks amphiphilicity and porin activity, adopts an extended inflexible structure, and, in T. pallidum, is tightly bound to the protoplasmic cylinder. By thermal denaturation, the MOSP(N) and MOSP(C)-like domains of TprC and TprI are highly thermostable, endowing the full-length proteins with impressive conformational stability. When expressed in Escherichia coli with PelB signal sequences, TprC and TprI localize to the outer membrane, adopting bipartite topologies, whereas TprF is periplasmic. We propose that the MOSP(N)-like domains enhance the structural integrity of the cell envelope by anchoring the β-barrels within the periplasm. In addition to being bona fide T. pallidum rare outer membrane proteins, TprC/D and TprI represent a new class of dual function, bipartite bacterial OMP.

  4. Domain B protruding at the third beta strand of the alpha/beta barrel in barley alpha-amylase confers distinct isozyme-specific properties.

    PubMed

    Rodenburg, K W; Juge, N; Guo, X J; Søgaard, M; Chaix, J C; Svensson, B

    1994-04-01

    alpha-Amylases belong to the alpha/beta-barrel protein family in which the active site is created by residues located at the C-terminus of the beta strands and in the helix-connecting loops extending from these ends. In the alpha-amylase family, a small separate domain B protrudes at the C-terminus of the third beta strand of the (beta/alpha)8-barrel framework. The 80% identical barley alpha-amylase isozymes 1 and 2 (AMY1 and AMY2, respectively) differ in substrate affinity and turnover rate, CaCl2 stimulation of activity, sensitivity to the endogenous 21-kDa alpha-amylase/subtilisin inhibitor, and stability at low pH. To identify regions that confer these isozyme-specific variations, AMY1-AMY2 hybrid cDNAs were generated by in vivo homologous recombination in yeast. The hybrids AMY1-(1-90)-AMY2-(90-403) and AMY1-(1-161)-AMY2-(161-403) characterized in this study contain the 90-residue and 161-residue N-terminal sequences, respectively, of AMY1 and complementary C-terminal regions of AMY2. AMY1-(1-90)-AMY2-(90-403) comprises the 60-amino-acid domain B of AMY2 and resembles this isozyme in sensitivity to alpha-amylase/subtilisin inhibitor and its low affinity for the substrates p-nitrophenyl alpha-D-maltoheptaoside, amylose and the inhibitor acarbose. Only AMY1-(1-161)-AMY2-(161-403) and AMY1, which both share domain B, are stable at low pH. However, AMY2 and both hybrid AMY species, but not AMY1, show maximum enzyme activity on insoluble blue starch at approximately 10 mM CaCl2. Domain B thus determines several functional and stability properties that distinguish the barley alpha-amylase isozymes.

  5. Analysis of Mutations in Neurospora crassa ERMES Components Reveals Specific Functions Related to β-Barrel Protein Assembly and Maintenance of Mitochondrial Morphology

    PubMed Central

    Wideman, Jeremy G.; Lackey, Sebastian W. K.; Srayko, Martin A.; Norton, Kacie A.; Nargang, Frank E.

    2013-01-01

    The endoplasmic reticulum mitochondria encounter structure (ERMES) tethers the ER to mitochondria and contains four structural components: Mmm1, Mdm12, Mdm10, and Mmm2 (Mdm34). The Gem1 protein may play a role in regulating ERMES function. Saccharomyces cerevisiae and Neurospora crassa strains lacking any of Mmm1, Mdm12, or Mdm10 are known to show a variety of phenotypic defects including altered mitochondrial morphology and defects in the assembly of β-barrel proteins into the mitochondrial outer membrane. Here we examine ERMES complex components in N. crassa and show that Mmm1 is an ER membrane protein containing a Cys residue near its N-terminus that is conserved in the class Sordariomycetes. The residue occurs in the ER-lumen domain of the protein and is involved in the formation of disulphide bonds that give rise to Mmm1 dimers. Dimer formation is required for efficient assembly of Tom40 into the TOM complex. However, no effects are seen on porin assembly or mitochondrial morphology. This demonstrates a specificity of function and suggests a direct role for Mmm1 in Tom40 assembly. Mutation of a highly conserved region in the cytosolic domain of Mmm1 results in moderate defects in Tom40 and porin assembly, as well as a slight morphological phenotype. Previous reports have not examined the role of Mmm2 with respect to mitochondrial protein import and assembly. Here we show that absence of Mmm2 affects assembly of β-barrel proteins and that lack of any ERMES structural component results in defects in Tom22 assembly. Loss of N. crassa Gem1 has no effect on the assembly of these proteins but does affect mitochondrial morphology. PMID:23940790

  6. Flow tests of the Gladys McCall well. Appendix A, Gladys McCall Site (Cameron Parish, LA): Final report, October 1985--October 1990

    SciTech Connect

    Randolph, P.L.; Hayden, C.G.; Rogers, L.A.

    1992-04-01

    This report pulls together the data from all of the geopressured-geothermal field research conducted at the Gladys McCall well. The well produced geopressured brine containing dissolved natural gas from the Lower Miocene sands at a depth of 15,150 to 16,650 feet. More than 25 million barrels of brine and 727 million standard cubic feet of natural gas were produced in a series of flow tests between December 1982 and October 1987 at various brine flow rates up to 28,000 barrels per day. Initial short-term flow tests for the Number 9 Sand found the permeability to be 67 to 85 md (millidarcies) for a brine volume of 85 to 170 million barrels. Initial short-term flow tests for the Number 8 Sand found a permeability of 113 to 132 md for a reservoir volume of 430 to 550 million barrels of brine. The long-term flow and buildup test of the Number 8 Sand found that the high-permeability reservoir connected to the wellbore (measured by the short-term flow test) was connected to a much larger, low-permeability reservoir. Numerical simulation of the flow and buildup tests required this large connected reservoir to have a volume of about 8 billion barrels (two cubic miles of reservoir rock) with effective permeabilities in the range of 0.2 to 20 md. Calcium carbonate scale formation in the well tubing and separator equipment was a problem. During the first 2 years of production, scale formation was prevented in the surface equipment by injection of an inhibitor upstream of the choke. Starting in 1985, scale formation in the production tubing was successfully prevented by injecting inhibitor ``pills`` directly into the reservoir. Corrosion and/or erosion of surface piping and equipment, as well as disposal well tubing, was also significant.

  7. Structural Basis for Substrate Specificity in Phosphate Binding (beta/alpha)8-Barrels: D-Allulose 6-Phosphate 3-Epimerase from Escherichia coli K-12

    SciTech Connect

    Chan,K.; Fedorov, A.; Almo, S.; Gerlt, J.

    2008-01-01

    Enzymes that share the ({beta}/{alpha})8-barrel fold catalyze a diverse range of reactions. Many utilize phosphorylated substrates and share a conserved C-terminal ({beta}/a)2-quarter barrel subdomain that provides a binding motif for the dianionic phosphate group. We recently reported functional and structural studies of d-ribulose 5-phosphate 3-epimerase (RPE) from Streptococcus pyogenes that catalyzes the equilibration of the pentulose 5-phosphates d-ribulose 5-phosphate and d-xylulose 5-phosphate in the pentose phosphate pathway [J. Akana, A. A. Fedorov, E. Fedorov, W. R. P. Novack, P. C. Babbitt, S. C. Almo, and J. A. Gerlt (2006) Biochemistry 45, 2493-2503]. We now report functional and structural studies of d-allulose 6-phosphate 3-epimerase (ALSE) from Escherichia coli K-12 that catalyzes the equilibration of the hexulose 6-phosphates d-allulose 6-phosphate and d-fructose 6-phosphate in a catabolic pathway for d-allose. ALSE and RPE prefer their physiological substrates but are promiscuous for each other's substrate. The active sites (RPE complexed with d-xylitol 5-phosphate and ALSE complexed with d-glucitol 6-phosphate) are superimposable (as expected from their 39% sequence identity), with the exception of the phosphate binding motif. The loop following the eighth {beta}-strand in ALSE is one residue longer than the homologous loop in RPE, so the binding site for the hexulose 6-phosphate substrate/product in ALSE is elongated relative to that for the pentulose 5-phosphate substrate/product in RPE. We constructed three single-residue deletion mutants of the loop in ALSE, ?T196, ?S197 and ?G198, to investigate the structural bases for the differing substrate specificities; for each, the promiscuity is altered so that d-ribulose 5-phosphate is the preferred substrate. The changes in kcat/Km are dominated by changes in kcat, suggesting that substrate discrimination results from differential transition state stabilization. In both ALSE and RPE, the phosphate

  8. Reduced inhibitory gate in the barrel cortex of Neuroligin3R451C knock‐in mice, an animal model of autism spectrum disorders

    PubMed Central

    Cellot, Giada; Cherubini, Enrico

    2014-01-01

    Abstract Neuroligins are postsynaptic adhesion molecules that interacting with presynaptic neurexins ensure the cross‐talk between pre‐ and postsynaptic specializations. Rare mutations in neurexin–neuroligin genes have been linked to autism spectrum disorders (ASDs). One of these, the R451C mutation of the gene encoding for Neuroligin3 (Nlgn3), has been found in patients with familial forms of ASDs. Animals carrying this mutation (NL3R451C knock‐in mice) exhibit impaired social behaviors, reminiscent of those observed in ASD patients, associated with major alterations in both GABAergic and glutamatergic transmission, which vary among different brain regions and at different developmental stages. Here, pair recordings from parvalbumin‐ (PV) expressing basket cells and spiny neurons were used to study GABAergic synaptic signaling in layer IV barrel cortex of NL3R451C mutant mice. We found that the R451C mutation severely affects the probability of GABA release from PV‐expressing basket cells, responsible for controlling via thalamo‐cortical inputs the feed‐forward inhibition. No changes in excitatory inputs to parvalbumin‐positive basket cells or spiny neurons were detected. These data clearly show that primary targets of the NL3 mutation are PV‐expressing basket cells, independently of the brain region where they are localized. Changes in the inhibitory gate of layer IV somatosensory cortex may alter sensory processing in ASD patients leading to misleading sensory representations with difficulties to combine pieces of information into a unified perceptual whole. PMID:25347860

  9. MiAMP1, a novel protein from Macadamia integrifolia adopts a Greek key beta-barrel fold unique amongst plant antimicrobial proteins.

    PubMed

    McManus, A M; Nielsen, K J; Marcus, J P; Harrison, S J; Green, J L; Manners, J M; Craik, D J

    1999-10-29

    MiAMP1 is a recently discovered 76 amino acid residue, highly basic protein from the nut kernel of Macadamia integrifolia which possesses no sequence homology to any known protein and inhibits the growth of several microbial plant pathogens in vitro while having no effect on mammalian or plant cells. It is considered to be a potentially useful tool for the genetic engineering of disease resistance in transgenic crop plants and for the design of new fungicides. The three-dimensional structure of MiAMP1 was determined through homonuclear and heteronuclear ((15)N) 2D NMR spectroscopy and subsequent simulated annealing calculations with the ultimate aim of understanding the structure-activity relationships of the protein. MiAMP1 is made up of eight beta-strands which are arranged in two Greek key motifs. These Greek key motifs associate to form a Greek key beta-barrel. This structure is unique amongst plant antimicrobial proteins and forms a new class which we term the beta-barrelins. Interestingly, the structure of MiAMP1 bears remarkable similarity to a yeast killer toxin from Williopsis mrakii. This toxin acts by inhibiting beta-glucan synthesis and thereby cell wall construction in sensitive strains of yeast. The structural similarity of MiAMP1 and WmKT, which originate from plant and fungal phyla respectively, may reflect a similar mode of action.

  10. Investigation of EMIC wave scattering as the cause for the BARREL 17 January 2013 relativistic electron precipitation event: A quantitative comparison of simulation with observations

    SciTech Connect

    Li, Zan; Millan, Robyn M.; Hudson, Mary K.; Woodger, Leslie A.; Smith, David M.; Chen, Yue; Friedel, Reiner; Rodriguez, Juan V.; Engebretson, Mark J.; Goldstein, Jerry; Fennell, Joseph F.; Spence, Harlan E.

    2014-12-23

    Electromagnetic ion cyclotron (EMIC) waves were observed at multiple observatory locations for several hours on 17 January 2013. During the wave activity period, a duskside relativistic electron precipitation (REP) event was observed by one of the Balloon Array for Radiation belt Relativistic Electron Losses (BARREL) balloons and was magnetically mapped close to Geostationary Operational Environmental Satellite (GOES) 13. We simulate the relativistic electron pitch angle diffusion caused by gyroresonant interactions with EMIC waves using wave and particle data measured by multiple instruments on board GOES 13 and the Van Allen Probes. We show that the count rate, the energy distribution, and the time variation of the simulated precipitation all agree very well with the balloon observations, suggesting that EMIC wave scattering was likely the cause for the precipitation event. The event reported here is the first balloon REP event with closely conjugate EMIC wave observations, and our study employs the most detailed quantitative analysis on the link of EMIC waves with observed REP to date.

  11. Investigation of EMIC wave scattering as the cause for the BARREL 17 January 2013 relativistic electron precipitation event: A quantitative comparison of simulation with observations

    DOE PAGES

    Li, Zan; Millan, Robyn M.; Hudson, Mary K.; ...

    2014-12-23

    Electromagnetic ion cyclotron (EMIC) waves were observed at multiple observatory locations for several hours on 17 January 2013. During the wave activity period, a duskside relativistic electron precipitation (REP) event was observed by one of the Balloon Array for Radiation belt Relativistic Electron Losses (BARREL) balloons and was magnetically mapped close to Geostationary Operational Environmental Satellite (GOES) 13. We simulate the relativistic electron pitch angle diffusion caused by gyroresonant interactions with EMIC waves using wave and particle data measured by multiple instruments on board GOES 13 and the Van Allen Probes. We show that the count rate, the energy distribution,more » and the time variation of the simulated precipitation all agree very well with the balloon observations, suggesting that EMIC wave scattering was likely the cause for the precipitation event. The event reported here is the first balloon REP event with closely conjugate EMIC wave observations, and our study employs the most detailed quantitative analysis on the link of EMIC waves with observed REP to date.« less

  12. Effects of sponge bleaching on ammonia-oxidizing Archaea: distribution and relative expression of ammonia monooxygenase genes associated with the barrel sponge Xestospongia muta.

    PubMed

    López-Legentil, Susanna; Erwin, Patrick M; Pawlik, Joseph R; Song, Bongkeun

    2010-10-01

    Sponge-mediated nitrification is an important process in the nitrogen cycle, however, nothing is known about how nitrification and symbiotic Archaea may be affected by sponge disease and bleaching events. The giant barrel sponge Xestospongia muta is a prominent species on Caribbean reefs that contains cyanobacterial symbionts, the loss of which results in two types of bleaching: cyclic, a recoverable condition; and fatal, a condition associated with the disease-like sponge orange band (SOB) syndrome and sponge death. Terminal restriction fragment length polymorphism (TRFLP) analyses, clone libraries, and relative mRNA quantification of ammonia monooxygenase genes (amoA) were performed using a RNA transcript-based approach to characterize the active ammonia-oxidizing Archaea (AOA) community present in bleached, non-bleached, and SOB tissues of cyclically and fatally bleached sponges. We found that non-bleached and cyclically bleached tissues of X. muta harbored a unique Crenarchaeota community closely related to those reported for other sponges. In contrast, bleached tissue from the most degraded sponge contained a Crenarchaeota community that was more similar to those found in sediment and sand. Although there were no significant differences in amoA expression among the different tissues, amoA expression was higher in the most deteriorated tissues. Results suggest that a shift in the Crenarchaeota community precedes an increase in amoA gene expression in fatally bleached sponges, while cyclic bleaching did not alter the AOA community structure and its amoA gene expression.

  13. Exploring the Structure-Function Loop Adaptability of a (β/α)(8)-Barrel Enzyme through Loop Swapping and Hinge Variability.

    PubMed

    Ochoa-Leyva, Adrián; Barona-Gómez, Francisco; Saab-Rincón, Gloria; Verdel-Aranda, Karina; Sánchez, Filiberto; Soberón, Xavier

    2011-08-05

    Evolution of proteins involves sequence changes that are frequently localized at loop regions, revealing their important role in natural evolution. However, the development of strategies to understand and imitate such events constitutes a challenge to design novel enzymes in the laboratory. In this study, we show how to adapt loop swapping as semiautonomous units of functional groups in an enzyme with the (β/α)(8)-barrel and how this functional adaptation can be measured in vivo. To mimic the natural mechanism providing loop variability in antibodies, we developed an overlap PCR strategy. This includes introduction of sequence diversity at two hinge residues, which connect the new loops with the rest of the protein scaffold, and we demonstrate that this is necessary for a successful exploration of functional sequence space. This design allowed us to explore the sequence requirements to functional adaptation of each loop replacement that may not be sampled otherwise. Libraries generated following this strategy were evaluated in terms of their folding competence and their functional proficiency, an observation that was formalized as a Structure-Function Loop Adaptability value. Molecular details about the function and structure of some variants were obtained by enzyme kinetics and circular dichroism. This strategy yields functional variants that retain the original activity at higher frequencies, suggesting a new strategy for protein engineering that incorporates a more divergent sequence exploration beyond that limited to point mutations. We discuss how this approach may provide insights into the mechanism of enzyme evolution and function.

  14. Phenolic compounds and sensorial characterization of wines aged with alternative to barrel products made of Spanish oak wood (Quercus pyrenaica Willd.).

    PubMed

    Gallego, L; Del Alamo, M; Nevares, I; Fernández, J A; Fernández de Simón, B; Cadahía, E

    2012-04-01

    Wood of Quercus pyrenaica has suitable properties for the wine ageing process. However, the forest available for the barrel making from this particular type of tree is very limited. Nevertheless, it is highly advisable to use this kind of wood in order to manufacture alternative oak products. This study presents the results of ageing the same red wine using different pieces of wood (chips and staves) of Spanish oak (Q. pyrenaica), American oak (Quercus alba) and French oak (Quercus petraea) in conjunction with small, controlled amounts of oxygen. In addition, the phenolic parameters, colour and sensory analysis point out that wines aged with Q. pyrenaica pieces have similar enological characteristics to those aged with American or French oak pieces of wood (chips and staves). Furthermore, the total oxygen consumed and its relation with sensory properties also has been studied in this article in order to know how the oxygen behaves in these processes. Besides, it is going to put forward the fact that chips and staves from Q. pyrenaica oak are suitable for the ageing of red wines and better considered than American or French ones, showing higher aromatic intensity, complexity, woody, balsamic and cocoa. Finally, the tasters valued highly the wines with staves, pointing out its flavour and roundness in mouth.

  15. LL/ILW: Post-Qualification of Old Waste through Non-Destructive Extraction of Barrels from Cement Shields - 13535

    SciTech Connect

    Oehmigen, Steffen; Ambos, Frank

    2013-07-01

    Currently there is a large number of radioactive waste drums entombed in cement shields at German nuclear power plants. These concrete containers used in the past for the waste are not approved for the final repository. Compliance with current acceptance criteria of the final repository has to be proven by qualification measures on the waste. To meet these criteria, a new declaration and new packing is necessary. A simple non-destructive extraction of about 2000 drums from their concrete shields is not possible. So different methods were tested to find a way of non-destructive extraction of old waste drums from cement shields and therefore reduce the final repository volume and final repository costs by using a container accepted and approved for Konrad. The main objective was to build a mobile system to offer this service to nuclear plant stations. (authors)

  16. Internally damped, self-arresting vertical drop-weight impact test apparatus

    NASA Technical Reports Server (NTRS)

    Ambur, Damodar R. (Inventor); Prasad, Chunchu B. (Inventor); Waters, Jr., William A. (Inventor); Stockum, Robert W. (Inventor); Walter, Manfred A. (Inventor)

    1996-01-01

    A vertical dropped-weight impact test machine has a dropped-weight barrel vertically supported on upper and lower support brackets. The dropped-weight barrel is chambered to receive a dropped-weight assembly having a latch pin at its upper end, a damping unit in the middle, and a tup at its lower end. The tup is adapted for gathering data during impact testing. The latch pin releasably engages a latch pin coupling assembly. The latch pin coupling assembly is attached to a winch via a halyard for raising and lowering the dropped-weight assembly. The lower end of the dropped-weight barrel is provided with a bounce-back arresting mechanism which is activated by the descending passage of the dropped-weight assembly. After striking the specimen, the dropped-weight assembly rebounds vertically and is caught by the bounce-back arresting mechanism. The damping unit of the dropped-weight assembly serves to dissipate energy from the rebounding dropped-weight assembly and prevents the dropped-weight assembly from rebounding from the self-arresting mechanism.

  17. Internally damped, self-arresting vertical drop-weight impact test apparatus

    NASA Technical Reports Server (NTRS)

    Ambur, Damodar R. (Inventor); Prasad, Chunchu B. (Inventor); Waters, Jr., William A. (Inventor); Stockum, Robert W. (Inventor); Water, Manfred A. (Inventor)

    1995-01-01

    A vertical dropped-weight impact test machine has a dropped-weight barrel vertically supported on upper and lower support brackets. The dropped-weight barrel is chambered to receive a dropped-weight assembly having a latch pin at its upper end, a damping unit in the middle, and a tup at its lower end. The tup is adapted for gathering data during impact testing. The latch pin releasably engages a latch pin coupling assembly. The latch pin coupling assembly is attached to a winch via a halyard for raising and lowering the dropped-weight assembly. The lower end of the dropped-weight barrel is provided with a bounce-back arresting mechanism which is activated by the descending passage of the dropped-weight assembly. After striking the specimen, the dropped-weight assembly rebounds vertically and is caught by the bounce-back arresting mechanism. The damping unit of the dropped-weight assembly serves to dissipate energy from the rebounding dropped-weight assembly and prevents the dropped-weight assembly from rebounding from the self-arresting mechanism.

  18. Parametric analysis of thermal stratification during the Monju turbine trip test

    SciTech Connect

    Sofu, T.

    2012-07-01

    CFD-based simulation techniques are evaluated using a simplified symmetric Monju model to study multi-dimensional mixing and heat transfer in the upper plenum during a turbine trip test. When the test starts and core outlet temperatures drop due to reactor shutdown, the cooler sodium is trapped near the bottom of the vessel and the hotter (less dense) primary sodium at the higher elevations stays largely stagnant for an extended period of time inhibiting natural circulation. However, the secondary flow through a set of holes on the inner barrel bypasses the thermally stratified region as a shorter path to the intermediate heat exchanger and improves the natural circulation flow rate to cool the core. The calculations with strict adherence to benchmark specifications predict a much shorter duration for thermal stratification in the upper plenum than the experimental data indicates. In this paper, the results of a parametric analysis are presented to address this discrepancy. Specifically, the role of the holes on the inner barrel is reassessed in terms of their ability to provide larger by-pass flow. Assuming inner barrel holes with rounded edge produces results more consistent with the experiments. (authors)

  19. EXPERIMENTAL TARGET INJECTION AND TRACKING SYSTEM CONSTRUCTION AND SINGLE SHOT TESTING

    SciTech Connect

    PETZOLDT,R.W; ALEXANDER,N.B; DRAKE,T.J; GOODIN,D.T; JONESTRACK,K; VERMILLION,B.A

    2003-09-01

    Targets must be injected into an IFE power plant at a rate of approximately 5 to 10 Hz. Targets must be tracked very accurately to allow driver beams to be aligned with defined points on the targets with accuracy {+-} 150 {micro}m for indirect drive and {+-} 20 {micro}m for direct drive. An experimental target injection and tracking system has been constructed at General Atomics. The injector system will be used as a tool for testing the survivability of various target designs and provide feedback to the target designers. Helium gas propels the targets down an 8 m gun barrel up to 400 m/s. Direct-drive targets are protected in the barrel by sabots that are spring loaded to separate into two halves after acceleration. A sabot deflector directs the sabot halves away from the target injection path. Targets will be optically tracked with laser beams and line-scan cameras. Target position and arrival time will be predicted in real time based on early target position measurements. The system installation will be described. System testing to overcome excessive projectile wear and debris in the gun barrel is presented.

  20. Test Operations Procedure (TOP) 3-2-045 Small Arms - Hand and Shoulder Weapons and Machine Guns

    DTIC Science & Technology

    2007-09-17

    NDT ), such as magnetic particle or dye penetrant inspection, of components subjected to stress during firing (e.g., bolt, locking lugs, barrel, muzzle...Firing pin energy or indent (if specified in test plan). (3) Trigger pull (force and stroke required to manually operate the trigger...September 2007 15 4.3.2 Method. a. Hand and Shoulder Weapons. (1) Disassemble, thoroughly clean, inspect (including NDT of critical

  1. A review of sub acute subdural hematoma (SASDH) with our institutional experience and its management by double barrel technique (DbT): A novel technique

    PubMed Central

    Tripathy, Soubhagya R.; Swarnakar, Pankaj K.; Mishra, Sanjib; Mishra, Sudhanshu S.; Dhir, Manmath K.; Behera, Sanjay K.; Nath, Pratap C.; Jena, Somnath P.; Mohanta, Itibrata; Das, Deepak; Satapathy, Mani C.; Rout, Sitansu K.; Behera, Bikash R.; Parida, Deepak K.; Rath, Tanushree S.

    2016-01-01

    Background: Subacute subdural hematoma (SASDH) is an entity which is yet to capture the popular imagination among the neurosurgeons. Its management is often equated clinically to that of the chronic subdural hematoma (CSDH). However, their neurological deterioration is usually rapid, which seems to align them with acute subdural hematoma (ASDH). We proceed for their epidemiological evaluation. The advantages of a novel “double barrel technique (DbT)” over the conventional burrhole drainage are also presented. Methods: This retrospective study was conducted on all the patients having clinical and radiological evidence of SASDH, admitted to a tertiary care referral institute, during the period August 2013 to December 2015. Postoperatively, patients were followed-up for 3–24 months. Results: 46.87% of the patients belonged to the 35–54 year age group with a male predominance (3.6:1); 68.7% had a history of alcohol abuse, whereas aspirin users were 25%. 87.5% cases were unilateral, 18.75% were hemispheric, and 46.87% were present on the left side. Altered consciousness (100%) followed by headache (37.5%) were the most common presenting clinical features. Conclusion: SASDH is an uncommon neurosurgical entity (0.89% of traumatic brain injury cases in our study) and mimics both CSDH as well as ASDH. The true incidence of SASDH may have been underestimated due to its clinical imitation with CSDH. This study in a South Asian nation also provides the epidemiological data of this rare neurosurgical entity. Outcome of surgery is good; our retrospective study confirms that “DbT” is an adequate and safe treatment. However, a better designed, randomized control trial will be needed to reinforce our findings. PMID:27904759

  2. High-Affinity Binding of the Staphylococcal HarA Protein to Haptoglobin and Hemoglobin Involves a Domain with an Antiparallel Eight-Stranded β-Barrel Fold▿

    PubMed Central

    Dryla, Agnieszka; Hoffmann, Bernd; Gelbmann, Dieter; Giefing, Carmen; Hanner, Markus; Meinke, Andreas; Anderson, Annaliesa S.; Koppensteiner, Walter; Konrat, Robert; von Gabain, Alexander; Nagy, Eszter

    2007-01-01

    Iron scavenging from the host is essential for the growth of pathogenic bacteria. In this study, we further characterized two staphylococcal cell wall proteins previously shown to bind hemoproteins. HarA and IsdB harbor homologous ligand binding domains, the so called NEAT domain (for “near transporter”) present in several surface proteins of gram-positive pathogens. Surface plasmon resonance measurements using glutathione S-transferase (GST)-tagged HarAD1, one of the ligand binding domains of HarA, and GST-tagged full-length IsdB proteins confirmed high-affinity binding to hemoglobin and haptoglobin-hemoglobin complexes with equilibrium dissociation constants (KD) of 5 to 50 nM. Haptoglobin binding could be detected only with HarA and was in the low micromolar range. In order to determine the fold of this evolutionarily conserved ligand binding domain, the untagged HarAD1 protein was subjected to nuclear magnetic resonance spectroscopy, which revealed an eight-stranded, purely antiparallel β-barrel with the strand order (-β1↓-β2↑-β3↓-β6↑-β5↓-β4↑-β7↓-β8↑), forming two Greek key motifs. Based on structural-homology searches, the topology of the HarAD1 domain resembles that of the immunoglobulin (Ig) fold family, whose members are involved in protein-protein interactions, but with distinct structural features. Therefore, we consider that the HarAD1/NEAT domain fold is a novel variant of the Ig fold that has not yet been observed in other proteins. PMID:17041047

  3. Overexpression of human SOD1 in VDAC1-less yeast restores mitochondrial functionality modulating beta-barrel outer membrane protein genes.

    PubMed

    Magrì, Andrea; Di Rosa, Maria Carmela; Tomasello, Marianna Flora; Guarino, Francesca; Reina, Simona; Messina, Angela; De Pinto, Vito

    2016-06-01

    Cu/Zn Superoxide Dismutase (SOD1), the most important antioxidant defense against ROS in eukaryotic cells, localizes in cytosol and intermembrane space of mitochondria (IMS). Several evidences show a SOD1 intersection with both fermentative and respiratory metabolism. The Voltage Dependent Anion Channel (VDAC) is the main pore-forming protein in the mitochondrial outer membrane (MOM), and is considered the gatekeeper of mitochondrial metabolism. Saccharomyces cerevisiae lacking VDAC1 (Δpor1) is a very convenient model system, since it shows an impaired growth rate on non-fermentable carbon source. Transformation of Δpor1 yeast with human SOD1 completely restores the cell growth deficit in non-fermentative conditions and re-establishes the physiological levels of ROS, as well as the mitochondrial membrane potential. No similar result was found upon yeast SOD1 overexpression. A previous report highlighted the action of SOD1 as a transcription factor. Quantitative Real-Time PCR showed that β-barrel outer-membrane encoding-genes por2, tom40, sam50 are induced by hSOD1, but the same effect was not obtained in Δpor1Δpor2 yeast, indicating a crucial function for yVDAC2. Since the lack of VDAC1 in yeast can be considered a stress factor for the cell, hSOD1 could relieve it stimulating the expression of genes bringing to the recovery of the MOM function. Our results suggest a direct influence of SOD1 on VDAC.

  4. Impact Testing and Simulation of a Sinusoid Foam Sandwich Energy Absorber

    NASA Technical Reports Server (NTRS)

    Jackson, Karen E.; Fasanella, Edwin L; Littell, Justin D.

    2015-01-01

    A sinusoidal-shaped foam sandwich energy absorber was developed and evaluated at NASA Langley Research Center through multi-level testing and simulation performed under the Transport Rotorcraft Airframe Crash Testbed (TRACT) research project. The energy absorber, designated the "sinusoid," consisted of hybrid carbon- Kevlar® plain weave fabric face sheets, two layers for each face sheet oriented at +/-45deg with respect to the vertical or crush direction, and a closed-cell ELFOAM(TradeMark) P200 polyisocyanurate (2.0-lb/ft3) foam core. The design goal for the energy absorber was to achieve an average floor-level acceleration of between 25- and 40-g during the full-scale crash test of a retrofitted CH-46E helicopter airframe, designated TRACT 2. Variations in the design were assessed through quasi-static and dynamic crush testing of component specimens. Once the design was finalized, a 5-ft-long subfloor beam was fabricated and retrofitted into a barrel section of a CH-46E helicopter. A vertical drop test of the barrel section was conducted onto concrete to evaluate the performance of the energy absorber prior to retrofit into TRACT 2. Finite element models were developed of all test articles and simulations were performed using LSDYNA ®, a commercial nonlinear explicit transient dynamic finite element code. Test analysis results are presented for the sinusoid foam sandwich energy absorber as comparisons of load-displacement and acceleration-time-history responses, as well as predicted and experimental structural deformations and progressive damage for each evaluation level (component testing through barrel section drop testing).

  5. Cryogenic Tests of the ATLAS Liquid Argon Calorimeter

    NASA Astrophysics Data System (ADS)

    Bremer, J.; Chalifour, M.; Fabre, C.; Gonidec, A.; Passardi, G.

    2006-04-01

    The ATLAS liquid argon calorimeter consists of the barrel and two end-cap detectors housed in three independent cryostats filled with a total volume of 78 m3 of liquid argon. During cool-down the temperature differences in the composite structure of the detectors must be kept within strict limits to avoid excessive mechanical stresses and relative displacements. During normal operation the formation of gas bubbles, which are detrimental to the functioning of the detector, must be prevented and temperature gradients of less than 0.7 K across the argon bath are mandatory due to the temperature dependence of the energy measurements. Between April 2004 and May 2005 the barrel (120 t) and one end-cap (219 t) underwent qualification tests at the operating temperature of 87.3 K using a dedicated test facility at ground level. These tests provided a validation of the cooling methods to be adopted in the final underground configuration. In total 6.9 GJ and 15.7 GJ were extracted from the calorimeters and a temperature uniformity of the argon bath of less than 0.4 K was achieved.

  6. Pre-Test Analysis Predictions for the Shell Buckling Knockdown Factor Checkout Tests - TA01 and TA02

    NASA Technical Reports Server (NTRS)

    Thornburgh, Robert P.; Hilburger, Mark W.

    2011-01-01

    This report summarizes the pre-test analysis predictions for the SBKF-P2-CYL-TA01 and SBKF-P2-CYL-TA02 shell buckling tests conducted at the Marshall Space Flight Center (MSFC) in support of the Shell Buckling Knockdown Factor (SBKF) Project, NASA Engineering and Safety Center (NESC) Assessment. The test article (TA) is an 8-foot-diameter aluminum-lithium (Al-Li) orthogrid cylindrical shell with similar design features as that of the proposed Ares-I and Ares-V barrel structures. In support of the testing effort, detailed structural analyses were conducted and the results were used to monitor the behavior of the TA during the testing. A summary of predicted results for each of the five load sequences is presented herein.

  7. Supertyphoon Nepartak Barreling Towards Taiwan

    Atmospheric Science Data Center

    2016-12-30

    ... shows the central portion of Nepartak and the storm’s eye. The image is about 378 km (235 miles) across. The island of Manila in the ... miles south of Taiwan, is visible to the southwest of the eye. The image shows that Nepartak’s center is extremely compact, rather than ...

  8. Erosion in Large Gun Barrels

    DTIC Science & Technology

    1975-01-01

    Different propellants having the same flame temperature may cause variations in erosion by a factor of 4. Other aspects important to the mechanisms of...weights make for higher gun temperatures . Larger diameter gun tubes run cooler. Using the above, one may estimate the tube temperature for different ...Confronted with problems associated with the continual upgrading of field guns, reducing the number of different Items in supply and lowering overall costs

  9. Differential Inputs to the Perisomatic and Distal-Dendritic Compartments of VIP-Positive Neurons in Layer 2/3 of the Mouse Barrel Cortex

    PubMed Central

    Sohn, Jaerin; Okamoto, Shinichiro; Kataoka, Naoya; Kaneko, Takeshi; Nakamura, Kazuhiro; Hioki, Hiroyuki

    2016-01-01

    The recurrent network composed of excitatory and inhibitory neurons is fundamental to neocortical function. Inhibitory neurons in the mammalian neocortex are molecularly diverse, and individual cell types play unique functional roles in the neocortical microcircuit. Recently, vasoactive intestinal polypeptide-positive (VIP+) neurons, comprising a subclass of inhibitory neurons, have attracted particular attention because they can disinhibit pyramidal cells through inhibition of other types of inhibitory neurons, such as parvalbumin- (PV+) and somatostatin-positive (SOM+) inhibitory neurons, promoting sensory information processing. Although VIP+ neurons have been reported to receive synaptic inputs from PV+ and SOM+ inhibitory neurons as well as from cortical and thalamic excitatory neurons, the somatodendritic localization of these synaptic inputs has yet to be elucidated at subcellular spatial resolution. In the present study, we visualized the somatodendritic membranes of layer (L) 2/3 VIP+ neurons by injecting a newly developed adeno-associated virus (AAV) vector into the barrel cortex of VIP-Cre knock-in mice, and we determined the extensive ramification of VIP+ neuron dendrites in the vertical orientation. After immunohistochemical labeling of presynaptic boutons and postsynaptic structures, confocal laser scanning microscopy revealed that the synaptic contacts were unevenly distributed throughout the perisomatic (<100 μm from the somata) and distal-dendritic compartments (≥100 μm) of VIP+ neurons. Both corticocortical and thalamocortical excitatory neurons preferentially targeted the distal-dendritic compartment of VIP+ neurons. On the other hand, SOM+ and PV+ inhibitory neurons preferentially targeted the distal-dendritic and perisomatic compartments of VIP+ neurons, respectively. Notably, VIP+ neurons had few reciprocal connections. These observations suggest different inhibitory effects of SOM+ and PV+ neuronal inputs on VIP+ neuron activity

  10. Increased Stability and DNA Site Discrimination of Single Chain Variants of the Dimeric beta-Barrel DNA Binding Domain of the Human Papillomavirus E2 Transcriptional Regulator

    SciTech Connect

    Dellarole,M.; Sanchez, I.; Freire, E.; de Prat-Gay, G.

    2007-01-01

    Human papillomavirus infects millions of people worldwide and is a causal agent of cervical cancer in women. The HPV E2 protein controls the expression of all viral genes through binding of its dimeric C-terminal domain (E2C) to its target DNA site. We engineered monomeric versions of the HPV16 E2C, in order to probe the link of the dimeric {beta}-barrel fold to stability, dimerization, and DNA binding. Two single-chain variants, with 6 and 12 residue linkers (scE2C-6 and scE2C-12), were purified and characterized. Spectroscopy and crystallography show that the native structure is unperturbed in scE2C-12. The single chain variants are stabilized with respect to E2C, with effective concentrations of 0.6 to 6 mM. The early folding events of the E2C dimer and scE2C-12 are very similar and include formation of a compact species in the submillisecond time scale and a non-native monomeric intermediate with a half-life of 25 ms. However, monomerization changes the unfolding mechanism of the linked species from two-state to three-state, with a high-energy intermediate. Binding to the specific target site is up to 5-fold tighter in the single chain variants. Nonspecific DNA binding is up to 7-fold weaker in the single chain variants, leading to an overall 10-fold increased site discrimination capacity, the largest described so far for linked DNA binding domains. Titration calorimetric binding analysis, however, shows almost identical behavior for dimer and single-chain species, suggesting very subtle changes behind the increased specificity. Global analysis of the mechanisms probed suggests that the dynamics of the E2C domain, rather than the structure, are responsible for the differential properties. Thus, the plastic and dimeric nature of the domain did not evolve for a maximum affinity, specificity, and stability of the quaternary structure, likely because of regulatory reasons and for roles other than DNA binding played by partly folded dimeric or monomeric conformers.

  11. HYDRATE CORE DRILLING TESTS

    SciTech Connect

    John H. Cohen; Thomas E. Williams; Ali G. Kadaster; Bill V. Liddell

    2002-11-01

    -grain sand in ice. Results with this core showed that the viscosity of the drilling fluid must also be carefully controlled. When coarse sand was being cored, the core barrel became stuck because the drilling fluid was not viscous enough to completely remove the large grains of sand. These tests were very valuable to the project by showing the difficulties in coring permafrost or hydrates in a laboratory environment (as opposed to a field environment where drilling costs are much higher and the potential loss of equipment greater). Among the conclusions reached from these simulated hydrate coring tests are the following: Frozen hydrate core samples can be recovered successfully; A spring-finger core catcher works best for catching hydrate cores; Drilling fluid can erode the core and reduces its diameter, making it more difficult to capture the core; Mud must be designed with proper viscosity to lift larger cuttings; and The bottom 6 inches of core may need to be drilled dry to capture the core successfully.

  12. Effect of Lipid-Based Nanostructure on Protein Encapsulation within the Membrane Bilayer Mimetic Lipidic Cubic Phase Using Transmembrane and Lipo-proteins from the Beta-Barrel Assembly Machinery.

    PubMed

    van 't Hag, Leonie; Shen, Hsin-Hui; Lin, Tsung-Wu; Gras, Sally L; Drummond, Calum J; Conn, Charlotte E

    2016-11-29

    A fundamental understanding of the effect of amphiphilic protein encapsulation on the nanostructure of the bicontinuous cubic phase is crucial to progressing biomedical and biological applications of these hybrid protein-lipid materials, including as drug delivery vehicles, as biosensors, biofuel cells and for in meso crystallization. The relationship between the lipid nanomaterial and the encapsulated protein, however, remains poorly understood. In this study, we investigated the effect of incorporating the five transmembrane and lipo-proteins which make up the β-barrel assembly machinery from Gram-negative bacteria within a series of bicontinuous cubic phases. The transmembrane β-barrel BamA caused an increase in lattice parameter of the cubic phase upon encapsulation. By contrast, the mainly hydrophilic lipo-proteins BamB-E caused the cubic phase lattice parameters to decrease, despite their large size relative to the diameter of the cubic phase water channels. Analysis of the primary amino acid sequence was used to rationalize this effect, based on specific interactions between aromatic amino acids within the proteins and the polar-apolar interface. Other factors that were found to have an effect were lateral bilayer pressure and rigidity within the lipid bilayer, water channel diameter, and size and structure of the lipo-proteins. The data presented suggest that hydrophilic bioactive molecules can be selectively encapsulated within the cubic phase by using a lipid anchor or aromatic amino acids, for drug delivery or biosensing applications.

  13. Forelimb amputation-induced reorganization in the ventral posterior lateral nucleus (VPL) provides a substrate for large-scale cortical reorganization in rat forepaw barrel subfield (FBS).

    PubMed

    Li, Cheng X; Chappell, Tyson D; Ramshur, John T; Waters, Robert S

    2014-10-02

    In this study, we examined the role of the ventral posterior lateral nucleus (VPL) as a possible substrate for large-scale cortical reorganization in the forepaw barrel subfield (FBS) of primary somatosensory cortex (SI) that follows forelimb amputation. Previously, we reported that, 6 weeks after forelimb amputation in young adult rats, new input from the shoulder becomes expressed throughout the FBS that quite likely has a subcortical origin. Subsequent examination of the cuneate nucleus (CN) 1 to 30 weeks following forelimb amputation showed that CN played an insignificant role in cortical reorganization and led to the present investigation of VPL. As a first step, we used electrophysiological recordings in forelimb intact adult rats (n=8) to map the body representation in VPL with particular emphasis on the forepaw and shoulder representations and showed that VPL was somatotopically organized. We next used stimulation and recording techniques in forelimb intact rats (n=5) and examined the pattern of projection (a) from the forelimb and shoulder to SI, (b) from the forepaw and shoulder to VPL, and (c) from sites in the forepaw and shoulder representation in VPL to forelimb and shoulder sites in SI. The results showed that the projections were narrowly focused and homotopic. Electrophysiological recordings were then used to map the former forepaw representation in forelimb amputated young adult rats (n=5) at 7 to 24 weeks after amputation. At each time period, new input from the shoulder was observed in the deafferented forepaw region in VPL. To determine whether the new shoulder input in the deafferented forepaw VPL projected to a new shoulder site in the deafferented FBS, we examined the thalamocortical pathway in 2 forelimb-amputated rats. Stimulation of a new shoulder site in deafferented FBS antidromically-activated a cell in the former forepaw territory in VPL; however, similar stimulation from a site in the original shoulder representation, outside the

  14. Test Architecture, Test Retrofit

    ERIC Educational Resources Information Center

    Fulcher, Glenn; Davidson, Fred

    2009-01-01

    Just like buildings, tests are designed and built for specific purposes, people, and uses. However, both buildings and tests grow and change over time as the needs of their users change. Sometimes, they are also both used for purposes other than those intended in the original designs. This paper explores architecture as a metaphor for language…

  15. Research on structural design and test technologies for a three-chamber launching device.

    PubMed

    Jun, Wu; Qiushi, Yan; Ling, Xiao; Tieshuan, Zhuang; Chengyu, Yang

    2016-07-01

    A three-chamber launching device with improved acceleration is proposed and developed. As indicated by the damage generated during the pill and engineering protection tests, the proposed device is applicable as a high-speed launching platform for pills of different shapes and quality levels. Specifically, it can be used to investigate kinetic energy weapons and their highly destructive effects due to the resulting large bomb fragments. In the horizontal direction of the barrel, two auxiliary chambers are set at a certain distance from the main chamber. When the pill reaches the mouth of the auxiliary chambers, the charges in the auxiliary chambers are ignited by the high-temperature, high-pressure combustible gas trailing the pill. The combustible gas in the auxiliary chambers can resist the rear pressure of the pill and thus maintain the high pressure of the pill base. In this way, the required secondary acceleration of the pill is met. The proposed device features the advantage of launching a pill with high initial velocity under low bore pressure. Key techniques are proposed in the design of the device to address the problems related to the angle between the main chamber axis and the ancillary chamber axis, the overall design of a three-chamber barrel, the structural design of auxiliary propellant charge, the high-pressure combustible gas sealing technology, and the sabot and belt design. Results from the launching test verify the reasonable design of this device and its reliable structural sealing. Additionally, the stiffness and the strength of the barrel meet design requirements. Compared with the single-chamber launching device with the same caliber, the proposed device increases the average launching velocity by approximately 15% and the amount of muzzle kinetic energy by approximately 35%. Therefore, this equipment is capable of carrying out small-caliber, high-speed pill firing tests.

  16. Research on structural design and test technologies for a three-chamber launching device

    NASA Astrophysics Data System (ADS)

    Jun, Wu; Qiushi, Yan; Ling, Xiao; Tieshuan, Zhuang; Chengyu, Yang

    2016-07-01

    A three-chamber launching device with improved acceleration is proposed and developed. As indicated by the damage generated during the pill and engineering protection tests, the proposed device is applicable as a high-speed launching platform for pills of different shapes and quality levels. Specifically, it can be used to investigate kinetic energy weapons and their highly destructive effects due to the resulting large bomb fragments. In the horizontal direction of the barrel, two auxiliary chambers are set at a certain distance from the main chamber. When the pill reaches the mouth of the auxiliary chambers, the charges in the auxiliary chambers are ignited by the high-temperature, high-pressure combustible gas trailing the pill. The combustible gas in the auxiliary chambers can resist the rear pressure of the pill and thus maintain the high pressure of the pill base. In this way, the required secondary acceleration of the pill is met. The proposed device features the advantage of launching a pill with high initial velocity under low bore pressure. Key techniques are proposed in the design of the device to address the problems related to the angle between the main chamber axis and the ancillary chamber axis, the overall design of a three-chamber barrel, the structural design of auxiliary propellant charge, the high-pressure combustible gas sealing technology, and the sabot and belt design. Results from the launching test verify the reasonable design of this device and its reliable structural sealing. Additionally, the stiffness and the strength of the barrel meet design requirements. Compared with the single-chamber launching device with the same caliber, the proposed device increases the average launching velocity by approximately 15% and the amount of muzzle kinetic energy by approximately 35%. Therefore, this equipment is capable of carrying out small-caliber, high-speed pill firing tests.

  17. Vented Tank Resupply Experiment--Flight Test Results

    NASA Technical Reports Server (NTRS)

    Chato, David J.; Martin, Timothy A.

    1997-01-01

    This paper reports the results of the Vented Tank Resupply Experiment (VTRE) which was flown as a payload on STS 77. VTRE looks at the ability of vane Propellant Management Devices (PMD) to separate liquid and gas in low gravity. VTRE used two clear 0.8 cubic foot tanks one spherical and one with a short barrel section and transferred Refrigerant 113 between them as well as venting it to space. Tests included retention of liquid during transfer, liquid free venting, and recovery of liquid into the PMD after thruster firing. Liquid was retained successfully at the highest flow rate tested (2.73 gpm). Liquid free vents were achieved for both tanks, although at a higher flow rate (0.1591 cfm) for the spherical tank than the other (0.0400 cfm). Recovery from a thruster firing which moved the liquid to the opposite end of the tank from the PMD was achieved in 30 seconds.

  18. Testing geopressured geothermal reservoirs in existing wells. Saldana well No. 2, Zapata County, Texas. Volume I. Completion and testing. Final report

    SciTech Connect

    Not Available

    1981-10-07

    The Saldana Well No. 2, approximately 35 miles Southeast of the city of Laredo, Texas, was the sixth successful test of a geopressured-geothermal aquifer under the DOE Wells of Opportunity Program. The well was tested through the annulus between 7-inch casing and 2-3/8 inch tubing. The interval tested was from 9745 to 9820 feet. The geological section was the 1st Hinnant Sand, an upper member of the Wilcox Group. Produced water was injected into the Saldana Well No. 1, which was also acquired from Riddle Oil Company and converted to a disposal well. A Miocene salt water sand was perforated from 3005 to 3100 feet for disposal. One pressure drawdown flow test and one pressure buildup test were conducted during a 10-day period. A total of 9328 barrels of water was produced. The highest sustained flow rate was 1950 BWPD.

  19. Crystal structures of two bacterial 3-hydroxy-3-methylglutaryl-CoA lyases suggest a common catalytic mechanism among a family of TIM barrel metalloenzymes cleaving carbon-carbon bonds.

    PubMed

    Forouhar, Farhad; Hussain, Munif; Farid, Ramy; Benach, Jordi; Abashidze, Mariam; Edstrom, William C; Vorobiev, Sergey M; Xiao, Rong; Acton, Thomas B; Fu, Zhuji; Kim, Jung-Ja P; Miziorko, Henry M; Montelione, Gaetano T; Hunt, John F

    2006-03-17

    The enzyme 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) lyase catalyzes the terminal steps in ketone body generation and leucine degradation. Mutations in this enzyme cause a human autosomal recessive disorder called primary metabolic aciduria, which typically kills victims because of an inability to tolerate hypoglycemia. Here we present crystal structures of the HMG-CoA lyases from Bacillus subtilis and Brucella melitensis at 2.7 and 2.3 A resolution, respectively. These enzymes share greater than 45% sequence identity with the human orthologue. Although the enzyme has the anticipated triose-phosphate isomerase (TIM) barrel fold, the catalytic center contains a divalent cation-binding site formed by a cluster of invariant residues that cap the core of the barrel, contrary to the predictions of homology models. Surprisingly, the residues forming this cation-binding site and most of their interaction partners are shared with three other TIM barrel enzymes that catalyze diverse carbon-carbon bond cleavage reactions believed to proceed through enolate intermediates (4-hydroxy-2-ketovalerate aldolase, 2-isopropylmalate synthase, and transcarboxylase 5S). We propose the name "DRE-TIM metallolyases" for this newly identified enzyme family likely to employ a common catalytic reaction mechanism involving an invariant Asp-Arg-Glu (DRE) triplet. The Asp ligates the divalent cation, while the Arg probably stabilizes charge accumulation in the enolate intermediate, and the Glu maintains the precise structural alignment of the Asp and Arg. We propose a detailed model for the catalytic reaction mechanism of HMG-CoA lyase based on the examination of previously reported product complexes of other DRE-TIM metallolyases and induced fit substrate docking studies conducted using the crystal structure of human HMG-CoA lyase (reported in the accompanying paper by Fu, et al. (2006) J. Biol. Chem. 281, 7526-7532). Our model is consistent with extensive mutagenesis results and can

  20. Crystal Structures of Two Bacterial 3-Hydroxy-3-methylglutaryl-CoA Lyases Suggest a Common Catalytic Mechanism among a Family of TIM Barrel Metalloenzymes Cleaving Carbon-Carbon Bonds

    SciTech Connect

    Forouhar,F.; Hussain, M.; Farid, R.; Benach, J.; Abashidze, M.; Edstrom, W.; Vorobiev, S.; Montelione, G.; Hunt, J.; et al.

    2006-01-01

    The enzyme 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) lyase catalyzes the terminal steps in ketone body generation and leucine degradation. Mutations in this enzyme cause a human autosomal recessive disorder called primary metabolic aciduria, which typically kills victims because of an inability to tolerate hypoglycemia. Here we present crystal structures of the HMG-CoA lyases from Bacillus subtilis and Brucella melitensis at 2.7 and 2.3 {angstrom} resolution, respectively. These enzymes share greater than 45% sequence identity with the human orthologue. Although the enzyme has the anticipated triose-phosphate isomerase (TIM) barrel fold, the catalytic center contains a divalent cation-binding site formed by a cluster of invariant residues that cap the core of the barrel, contrary to the predictions of homology models. Surprisingly, the residues forming this cation-binding site and most of their interaction partners are shared with three other TIM barrel enzymes that catalyze diverse carbon-carbon bond cleavage reactions believed to proceed through enolate intermediates (4-hydroxy-2-ketovalerate aldolase, 2-isopropylmalate synthase, and transcarboxylase 5S). We propose the name 'DRE-TIM metallolyases' for this newly identified enzyme family likely to employ a common catalytic reaction mechanism involving an invariant Asp-Arg-Glu (DRE) triplet. The Asp ligates the divalent cation, while the Arg probably stabilizes charge accumulation in the enolate intermediate, and the Glu maintains the precise structural alignment of the Asp and Arg. We propose a detailed model for the catalytic reaction mechanism of HMG-CoA lyase based on the examination of previously reported product complexes of other DRE-TIM metallolyases and induced fit substrate docking studies conducted using the crystal structure of human HMG-CoA lyase (reported in the accompanying paper by Fu, et al. (2006) J. Biol. Chem. 281, 7526-7532). Our model is consistent with extensive mutagenesis results and

  1. Testing of Mortar Systems

    DTIC Science & Technology

    2010-03-11

    Measure chamber pressure through the use of external piezoelectric or copper- crusher gauges. The use of such gauges requires a mortar cannon/barrel...tube tapped to receive the gauges. If such a tube cannot be obtained, use other methods, such as strain gages or internal copper- crusher gauges to...measure chamber pressure. Refer to ITOP 3-2-810. Note: When employing external crusher gauges, it is important not to replace used gauges with new

  2. Test plan :

    SciTech Connect

    Dwyer, Stephen F.

    2013-05-01

    This test plan is a document that provides a systematic approach to the planned testing of rooftop structures to determine their actual load carrying capacity. This document identifies typical tests to be performed, the responsible parties for testing, the general feature of the tests, the testing approach, test deliverables, testing schedule, monitoring requirements, and environmental and safety compliance.

  3. Pinworm test

    MedlinePlus

    Oxyuriasis test; Enterobiasis test; Tape test ... diagnose this infection is to do a tape test. The best time to do this is in ... lay their eggs at night. Steps for the test are: Firmly press the sticky side of a ...

  4. Thyroid Tests

    MedlinePlus

    ... calories and how fast your heart beats. Thyroid tests check how well your thyroid is working. They ... thyroid diseases such as hyperthyroidism and hypothyroidism. Thyroid tests include blood tests and imaging tests. Blood tests ...

  5. Susceptibility Testing

    MedlinePlus

    ... Also known as: Sensitivity Testing; Drug Resistance Testing; Culture and Sensitivity; C & S; Antimicrobial Susceptibility Formal name: Bacterial and Fungal Susceptibility Testing Related tests: Urine Culture ; Blood Culture ; Bacterial Wound Culture ; AFB Testing ; MRSA ; ...

  6. Crystal structure of YwpF from Staphylococcus aureus reveals its architecture comprised of a β-barrel core domain resembling type VI secretion system proteins and a two-helix pair.

    PubMed

    Lee, Sang Jae; Lee, Kyu-Yeon; Lee, Ki-Young; Kim, Dong-Gyun; Kim, Soon-Jong; Lee, Bong-Jin

    2015-04-01

    The ywpF gene (SAV2097) of the Staphylococcus aureus strain Mu50 encodes the YwpF protein, which may play a role in antibiotic resistance. Here, we report the first crystal structure of the YwpF superfamily from S. aureus at 2.5-Å resolution. The YwpF structure consists of two regions: an N-terminal core β-barrel domain that shows structural similarity to type VI secretion system (T6SS) proteins (e.g., Hcp1, Hcp3, and EvpC) and a C-terminal two-helix pair. Although the monomer structure of S. aureus YwpF resembles those of T6SS proteins, the dimer/tetramer model of S. aureus YwpF is distinct from the functionally important hexameric ring of T6SS proteins. We therefore suggest that the S. aureus YwpF may have a different function compared to T6SS proteins.

  7. Functional outcome of en bloc resection of a giant cell tumour of the distal radius and arthrodesis of the wrist and distal ulna using an ipsilateral double barrel segmental ulna bone graft combined with a modified Sauve-Kapandji procedure.

    PubMed

    Zhang, W; Zhong, J; Li, D; Sun, C; Zhao, H; Gao, Y

    2016-08-25

    Giant cell tumour of the distal radius is a locally aggressive lesion. In this study, we performed a wrist arthrodesis reconstruction with an ipsilateral double barrel segmental ulnar bone graft combined with a modified Sauve-Kapandji procedure for a giant cell tumour of the distal radius. From January 2007 to September 2013, we followed eight patients for a mean duration of 36 months. One patient developed a recurrence and was treated by amputation; the other seven patients achieved radiological union in about 8 months. There was no wrist instability, deformation or dislocation; the mean range of motion of the forearm achieved 75° of supination and 70° of pronation. The patients could recover reasonable grip strength. This new operative procedure can excise the tumour with a low rate of recurrence, fewer functional deficits and fewer complications than reported for other procedures.

  8. Structure of L-Xylulose-5-Phosphate 3-Epimerase (UlaE) from the Anaerobic L-Ascorbate Utilization Pathway of Escherichia coli: Identification of a Novel Phosphate Binding Motif within a TIM Barrel Fold

    SciTech Connect

    Shi, Rong; Pineda, Marco; Ajamian, Eunice; Cui, Qizhi; Matte, Allan; Cygler, Miroslaw

    2009-01-15

    Three catabolic enzymes, UlaD, UlaE, and UlaF, are involved in a pathway leading to fermentation of L-ascorbate under anaerobic conditions. UlaD catalyzes a {beta}-keto acid decarboxylation reaction to produce L-xylulose-5-phosphate, which undergoes successive epimerization reactions with UlaE (L-xylulose-5-phosphate 3-epimerase) and UlaF (L-ribulose-5-phosphate 4-epimerase), yielding D-xylulose-5-phosphate, an intermediate in the pentose phosphate pathway. We describe here crystallographic studies of UlaE from Escherichia coli O157:H7 that complete the structural characterization of this pathway. UlaE has a triosephosphate isomerase (TIM) barrel fold and forms dimers. The active site is located at the C-terminal ends of the parallel {beta}-strands. The enzyme binds Zn{sup 2+}, which is coordinated by Glu155, Asp185, His211, and Glu251. We identified a phosphate-binding site formed by residues from the {beta}1/{alpha}1 loop and {alpha}3' helix in the N-terminal region. This site differs from the well-characterized phosphate-binding motif found in several TIM barrel superfamilies that is located at strands {beta}7 and {beta}8. The intrinsic flexibility of the active site region is reflected by two different conformations of loops forming part of the substrate-binding site. Based on computational docking of the L-xylulose 5-phosphate substrate to UlaE and structural similarities of the active site of this enzyme to the active sites of other epimerases, a metal-dependent epimerization mechanism for UlaE is proposed, and Glu155 and Glu251 are implicated as catalytic residues. Mutation and activity measurements for structurally equivalent residues in related epimerases supported this mechanistic proposal.

  9. Methodology for Mechanical Property Testing on Fuel Cladding Using an Expanded Plug Wedge Test

    SciTech Connect

    Wang, Jy-An John; Jiang, Hao

    2013-08-01

    compressive stresses were induced by clad bending deformation due to a clad bulging effect (or the barreling effect). The barreling effect caused very large localized shear stress in the clad and left testing material at a high risk of shear failure. The above combined effects will result in highly non-conservative predictions both in strength and ductility of the tested clad, and the associated mechanical properties as well. To overcome/mitigate the mentioned deficiencies associated with the current expansion plug test, systematic studies have been conducted. Through detailed parameter investigation on specific geometry designs, careful filtering of material for the expansion plug, as well as adding newly designed parts to the testing system, a method to reconcile the potential non-conservatism embedded in the expansion plug test system has been discovered. A modified expansion plug testing protocol has been developed based on the method. In order to closely resemble thin-wall theory, a general procedure was also developed to determine the hoop stress in the tested ring specimen. A scaling factor called -factor is defined to correlate the ring load P into hoop stress . , = . The generated stress-strain curve agrees very well with tensile test data in both the elastic and plastic regions.

  10. Pharmacogenomic Testing

    MedlinePlus

    ... Primary care providers Specialists Getting covered Research Basic science research Research in people ... screening Diagnostic testing Direct-to-consumer genetic testing Newborn screening Pharmacogenomic testing ...

  11. Predictive Testing

    MedlinePlus

    ... Primary care providers Specialists Getting covered Research Basic science research Research in people ... screening Diagnostic testing Direct-to-consumer genetic testing Newborn screening Pharmacogenomic testing ...

  12. Test results of high-precision large cryogenic lens holders

    NASA Astrophysics Data System (ADS)

    Gal, C.; Reutlinger, A.; Boesz, A.; Leberle, T.; Mottaghibonab, A.; Eckert, P.; Dubowy, M.; Gebler, H.; Grupp, F.; Geis, N.; Bode, A.; Katterloher, R.; Bender, R.

    2012-09-01

    For the Euclid mission a Pre-Development phase is implemented to prove feasibility of individual components of the system [1]. The Near Infrared Spectrometer and Photometer (NISP) of EUCLID requires high precision large lens holders (?170 mm) at cryogenic temperatures (150K). The four lenses of the optical system are made of different materials: fused silica, CaF2, and LF5G15 that are mounted in a separate lens barrel design. Each lens has its separate mechanical interface to the lens barrel, the so called adaption ring. The performance of the lens holder design is verified by adapted test equipment and test facility including an optical metrology system. The characterization of the lens deformation and displacement (decenter, tilt) due to mechanical loads of the holder itself as well as thermally induced loads are driven by the required submicron precision range and the operational thermal condition. The surface deformation of the lens and its holder is verified by interferometric measurements, while tilt and position accuracy are measured by in-situ fibre based distance sensors. The selected distance measurement sensors have the capability to measure in a few mm range with submicron resolution in ultra high vacuum, in vibration environments and at liquid nitrogen temperatures and below. The calibration of the measurement system is of crucial importance: impacts such as temperature fluctuation, surface roughness, surface reflectivity, straylight effects, etc. on the measured distance are carefully calibrated. Inbuilt thermal expansion effects of the fibre sensors are characterized and proven with lens dummy with quasi zero CTE. The paper presents the test results and measured performance of the high precision large cryogenic lens holders attained by the metrology system. These results are presented on behalf of the EUCLID consortium.

  13. Pregnancy Tests

    MedlinePlus

    ... Us Home A-Z Health Topics Pregnancy tests Pregnancy tests > A-Z Health Topics Pregnancy test fact ... To receive Publications email updates Enter email Submit Pregnancy tests If you think you may be pregnant , ...

  14. VDRL test

    MedlinePlus

    ... The VDRL test is a screening test for syphilis. It measures substances (proteins), called antibodies, that your ... come in contact with the bacteria that cause syphilis. How the Test is Performed The test is ...

  15. Coombs test

    MedlinePlus

    Direct antiglobulin test; Indirect antiglobulin test; Anemia - hemolytic ... No special preparation is necessary for this test. ... There are 2 types of the Coombs test: Direct Indirect The direct ... that are stuck to the surface of red blood cells. Many diseases ...

  16. Ham test

    MedlinePlus

    Acid hemolysin test; Paroxysmal nocturnal hemoglobinuria - Ham test; PNH - Ham test ... BJ. In: Chernecky CC, Berger BJ, eds. Laboratory Tests and Diagnostic Procedures . 6th ed. Philadelphia, PA: Elsevier ...

  17. Trichomonas Testing

    MedlinePlus

    ... Trichomonas vaginalis by Amplified Detection; Trichomonas vaginalis by Direct Fluorescent Antibody (DFA) Related tests: Pap Test , Chlamydia ... by one of the following methods: Molecular testing, direct DNA probes, or nucleic acid amplification tests (NAATs)— ...

  18. Tritium pellet injector design for tokamak fusion test reactor

    SciTech Connect

    Fisher, P.W.; Baylor, L.R.; Bryan, W.E.; Combs, S.K.; Easterly, C.E.; Lunsford, R.V.; Milora, S.L.; Schuresko, D.D.; White, J.A.; Williamson, D.H.

    1985-01-01

    A tritium pellet injector (TPI) system has been designed for the Tokamak Fusion Test Reactor (TFTR) Q approx. 1 phase of operation. The injector gun utilizes a radial design with eight independent barrels and a common extruder to minimize tritium inventory. The injection line contains guide tubes with intermediate vacuum pumping stations and fast valves to minimize propellant leakage to the torus. The vacuum system is designed for tritium compatibility. The entire injector system is contained in a glove box for secondary containment protection against tritium release. Failure modes and effects have been analyzed, and structural analysis has been performed for most intense predicted earthquake conditions. Details of the design and operation of this system are presented in this paper.

  19. Design and Analysis of Subscale and Full-Scale Buckling-Critical Cylinders for Launch Vehicle Technology Development

    NASA Technical Reports Server (NTRS)

    Hilburger, Mark W.; Lovejoy, Andrew E.; Thornburgh, Robert P.; Rankin, Charles

    2012-01-01

    NASA s Shell Buckling Knockdown Factor (SBKF) project has the goal of developing new analysis-based shell buckling design factors (knockdown factors) and design and analysis technologies for launch vehicle structures. Preliminary design studies indicate that implementation of these new knockdown factors can enable significant reductions in mass and mass-growth in these vehicles. However, in order to validate any new analysis-based design data or methods, a series of carefully designed and executed structural tests are required at both the subscale and full-scale levels. This paper describes the design and analysis of three different orthogrid-stiffeNed metallic cylindrical-shell test articles. Two of the test articles are 8-ft-diameter, 6-ft-long test articles, and one test article is a 27.5-ft-diameter, 20-ft-long Space Shuttle External Tank-derived test article.

  20. Vapor containment tests of the rapid response system glovebox. Final report, December 1995-April 1996

    SciTech Connect

    Arca, V.J.; Blewett, W.K.; Kinne, W.E.

    1996-10-01

    The Rapid Response System (RRS) is a trailer-mounted facility for demilitarizing Chemical Agent Identification Sets (CAIS), obsolete training kits containing ampules and/or bottles of chemical warfare agents (mustard and lewisite), or other industrial chemical compounds. The main component of the RRS is a glovebox divided into three areas - an airlock station, unpack station, and neutralization station, and the CAIS items are processed through each station by use of 11 glove ports. The glovebox is maintained at negative pressure differential by a gas-particulate filter-blower unit. To measure the performance of the glovebox in containing chemical vapors/gases, a series of tests was conducted on 811 April 1996 at Tooele Army Depot, UT, with methyl salicylate, a simulant for mustard. This testing addressed performance in steady state operation, airlock cycling, waste barrel changeout, and glove changeout. Two trials were also conducted in a simulated power-failure condition to determine the rate of leakage if system airflow is interrupted. The glovebox and its engineering controls provided a very high level of protection. Some procedural changes were recommended to increase the protection factor in glove and barrel changeout operations.

  1. Thyroid Tests

    MedlinePlus

    ... the thyroid, a computerized tomography (CT) scan, or nuclear medicine tests, to diagnose and find the cause ... is having the scan for other health problems. Nuclear medicine tests. Nuclear medicine tests of the thyroid ...

  2. Laboratory Tests

    MedlinePlus

    Laboratory tests check a sample of your blood, urine, or body tissues. A technician or your doctor ... compare your results to results from previous tests. Laboratory tests are often part of a routine checkup ...

  3. Lipase Test

    MedlinePlus

    ... known as: LPS Formal name: Lipase Related tests: Amylase , Trypsin , Trypsinogen At a Glance Test Sample The ... lipase is most often used, along with an amylase test , to help diagnose and monitor acute pancreatitis . ...

  4. IQ testing

    MedlinePlus

    IQ (intelligence quotient) testing is a series of exams used to determine your general intelligence in relation ... Many IQ tests are used today. Whether they measure actual intelligence or simply certain abilities is controversial. IQ tests ...

  5. Test Madness

    ERIC Educational Resources Information Center

    Hedrick, Wanda B., Ed.

    2007-01-01

    There's accountability and then there's the testing craze an iatrogenic practice that undermines real learning. Hedrick documents the negative effects of testing, giving teachers another weapon in their arsenal against mindless preparation for high-stakes tests.

  6. Chlamydia Testing

    MedlinePlus

    ... of testing for chlamydia. NAAT is a molecular test that detects the genetic material ( DNA ) of Chlamydia trachomatis . It is generally more sensitive and specific than other chlamydia tests and can be performed on a vaginal swab ...

  7. PILOT TESTING: PRETREATMENT OPTIONS TO ALLOW RE-USE OF FRAC FLOWBACK AND PRODUCED BRINE FOR GAS SHALE RESOURCE DEVELOPMENT

    SciTech Connect

    Burnett, David

    2012-12-31

    The goal of the A&M DOE NETL Project No. DE-FE0000847 was to develop a mobile, multifunctional water treatment capability designed specifically for “pre-treatment” of field waste brine. The project consisted of constructing s mobile “field laboratory” incorporating new technology for treating high salinity produced water and using the lab to conduct a side-by-side comparison between this new technology and that already existing in field operations. A series of four field trials were performed utilizing the mobile unit to demonstrate the effectiveness of different technology suitable for use with high salinity flow back brines and produced water. The design of the mobile unit was based on previous and current work at the Texas A&M Separation Sciences Pilot Plant. The several treatment techniques which have been found to be successful in both pilot plant and field tests had been tested to incorporate into a single multifunctional process train. Eight different components were evaluated during the trials, two types of oil and grease removal, one BTEX removal step, three micro-filters, and two different nanofilters. The performance of each technique was measured by its separation efficiency, power consumption, and ability to withstand fouling. The field trials were a success. Four different field brines were evaluated in the first trial in New York. Over 16,000 gallons of brine were processed. Using a power cost of $.10 per kWh, media pretreatment power use averaged $0.004 per barrel, solids removal $.04 per barrel and brine “softening” $.84 per barrel. Total power cost was approximately $1.00 per barrel of fluid treated. In Pennsylvania, brines collected from frac ponds were tested in two additional trials. Each of the brines was converted to an oil-free, solids-free brine with no biological activity. Brines were stable over time and would be good candidates for use as a make-up fluid in a subsequent fracturing fluid design. Reports on all of the field

  8. Testing Services

    NASA Technical Reports Server (NTRS)

    1993-01-01

    Trace Laboratories is an independent testing laboratory specializing in testing printed circuit boards, automotive products and military hardware. Technical information from NASA Tech Briefs and two subsequent JPL Technical Support packages have assisted Trace in testing surface insulation resistance on printed circuit board materials. Testing time was reduced and customer service was improved because of Jet Propulsion Laboratory technical support packages.

  9. RPR test

    MedlinePlus

    ... more specific test for syphilis, such as FTA-ABS . The FTA-ABS test will help distinguish between syphilis and other ... Elsevier Saunders; 2015:chap 239. Read More FTA-ABS test VDRL test Review Date 9/10/2015 ...

  10. Composite Testing

    DTIC Science & Technology

    2007-01-01

    Impact Test Matrix for Each Team Impact Tests Qty. Reqd. Per Team Dimensions Steel- GFRP Hybrid Specimen 3 40” x 12” GFRP Control...5: Tension Test Specimen Details Table 2: Tension Test Matrix for Each Team Tension Tests Qty. Reqd. Per Team Dimensions Steel- GFRP Hybrid...Specimen 6 12” L x 1-2” W GFRP Control Specimen 3 12” L x 1-2” W Numerical Modelling A detailed numerical model

  11. Physicochemical constraints of elevated pH affect efficient membrane interaction and arrest an abortive membrane-bound oligomeric intermediate of the beta-barrel pore-forming toxin Vibrio cholerae cytolysin.

    PubMed

    Rai, Anand Kumar; Kundu, Nidhi; Chattopadhyay, Kausik

    2015-10-01

    Vibrio cholerae cytolysin (VCC) is a potent membrane-damaging cytotoxic protein. VCC causes permeabilization of the target cell membranes by forming transmembrane oligomeric beta-barrel pores. Membrane pore formation by VCC involves following key steps: (i) membrane binding, (ii) formation of a pre-pore oligomeric intermediate, (iii) membrane insertion of the pore-forming motifs, and (iv) formation of the functional transmembrane pore. Membrane binding, oligomerization, and subsequent pore-formation process of VCC appear to be facilitated by multiple regulatory mechanisms that are only partly understood. Here, we have explored the role(s) of the physicochemical constraints, specifically imposed by the elevated pH conditions, on the membrane pore-formation mechanism of VCC. Elevated pH abrogates efficient interaction of VCC with the target membranes, and blocks its pore-forming activity. Under the elevated pH conditions, membrane-bound fractions of VCC remain trapped in the form of abortive oligomeric species that fail to generate the functional transmembrane pores. Such an abortive oligomeric assembly appears to represent a distinct, more advanced intermediate state than the pre-pore state. The present study offers critical insights regarding the implications of the physicochemical constraints for regulating the efficient membrane interaction and pore formation by VCC.

  12. Design and performance of serial powered single-sided modules within an integrated stave assembly for the ATLAS tracker barrel upgrade

    NASA Astrophysics Data System (ADS)

    Affolder, A.; Carrol, J.; Greenall, A.; Wormald, M.

    2010-12-01

    The design and performance of prototype single-sided modules with ABCN-25 front-end chips and 10x10 cm2 Hamamatsu silicon strip sensors is presented. A low mass module assembly has been achieved by gluing a single-sided flex circuit, with read out chips, directly onto the sensor. The design exploits the embedded shunt regulation within the ABCN-25 providing for a distributed and scalable powered architecture. This allows for multiple modules to be linked together serially to form larger stave structures of up to 12 modules. The stave's digital I/O is realised as a multi-drop LVDS bus flex cable glued to the stave core assembly using a custom receiver/transmitter ASIC (BCC). The results of preliminary electrical tests with 4 module stavelets will be presented.

  13. Research capabilities of the NASA Langley 8-foot high temperature tunnel

    NASA Technical Reports Server (NTRS)

    Puster, Richard L.

    1991-01-01

    The NASA Langley Research Center's 8-Foot High Temperature Tunnel (8' HTT) has been modified to facilitate the testing of hypersonic airbreathing propulsion systems in addition to aerothermal load definition and structural concept verification at Mach 4, 5, and 7. The 8' HTT simulates flight from 60 to 125 kft with run times of 1 to 2 min. The 8-ft diameter and 12-ft-long free jet length enables the testing of large engines or multiple subscale engines. Methane and air combustion products provide the true temperature environment; an oxygen system enriches the combustion products to the same volume fraction of oxygen as air to enable the testing of airbreathing engines. A hydrogen system provides model fuel for cooling and combustion. High use tunnel components have been upgraded or replaced.

  14. Pregnancy test

    MedlinePlus

    ... eds. Henry's Clinical Diagnosis and Management by Laboratory Methods . 22nd ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 25. Read More Ectopic pregnancy HCG blood test - qualitative HCG blood test - quantitative HCG in urine Miscarriage ...

  15. Prenatal Tests

    MedlinePlus

    ... may recommend you have an invasive test, like amniocentesis , to confirm the results. Chorionic villus sampling (also ... done at 15 to 22 weeks of pregnancy. Amniocentesis (also called amnio). Tests the amniotic fluid from ...

  16. Procalcitonin Test

    MedlinePlus

    ... Tests Online. AACC is a not-for-profit organization and does not endorse non-AACC products and services. Advertising & ... Complete Blood Count , Blood Culture , CSF Analysis All content on Lab Tests Online ...

  17. HPV Test

    MedlinePlus

    ... test for wider range of HPV types. 2009 Mar 13. US Food and Drug Administration. Available online ... approves two DNA tests to detect HPV. 2009 Mar 17. Infectious Disease News. Available online at http:// ...

  18. Potassium test

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/003484.htm Potassium test To use the sharing features on this ... enable JavaScript. This test measures the amount of potassium in the fluid portion (serum) of the blood. ...

  19. Kidney Tests

    MedlinePlus

    ... taking out waste products and making urine. Kidney tests check to see how well your kidneys are working. They include blood, urine, and imaging tests. Early kidney disease usually does not have signs ...

  20. Urodynamic Testing

    MedlinePlus

    ... the ability or inability to stop the urine flow in midstream. For precise measurements, imaging equipment takes pictures of the bladder filling ... postvoid residual measurement cystometric test leak point pressure measurement pressure flow ... urodynamic tests Uroflowmetry Uroflowmetry is ...